Monday, March 31, 2008

It sure was great to hear from....

I don't usually post personal stuff on the weather blog, but it was great to hear from a dear friend from college who has been faithfully following God's call, ministering in Japan for many years! Susan, as a missionary to Japan, serves in Tokyo at various campuses in reaching, teaching, and training university students. She works with Global University, the Assemblies of God education arm throughout the world. She found my video of us singing at the Chinese New Year Festival at UA in 1992. It made my day, to say the least, to hear from her.

To make this a "legit" weather post, here is the weather for Tokyo. As of this post, it is 59 degrees under partly cloudy skies. During the next 5 days highs will be between 57 and 64. Lows will be between 42 and 50. No rain is expected. At the moment winds are gusting as high as 45 mph out of the NW.

Check out Susan's blog!

Here is the video from 1992. Please don't laugh at my big glasses!

How this thing began two years ago

I got into this blogging thing just thinking that I would write a general blog about my family. Soon it became apparent that blogging was an ideal outlet to share my interest in weather. After a few months of blogging in early 2006, it became evident by April 2006, that I must share weather with others. The readership of this weather blog has grown exponentially. For that I am grateful! I sincerely thank each of you who take time to read! Having said all of that, I must admit that this is a labor of love. I like to learn, study, observe, and share about the weather.

One thing I must say is that I have been extremely blessed by meeting people who have become really good friends through this blog! Thanks to you all!

It all began in early April 2006 during a severe weather episode here in North Alabama. On 4/7/06 I saw three hail events that evening, one near Hartselle and a few minutes later, at 10:49, I saw tennis ball sized hail one mile north of Falkville. Finally, I saw a hail storm just before midnight in downtown Cullman.

When I started this blog I had not yet discovered how video could tell the story. As a matter of fact, I don't think video embedding was an option.

One of my most interesting "chase" experiences was April 7, 2006 when I endured three severe hail storms. I must admit that as a storm spotter, I "blew it" big time. I was in the wrong place at the wrong time. I knew it, too. I have never been more scared than when I realized that a strong area of rotation (including a reported funnel cloud) was approaching my area.

I saw three different hail storms, two of which are on this video. The first part of the video is the hail storm that occurred in southern Morgan County, one mile north of I-65 Exit 322 at Falkville. The second part of the video was from later than night in downtown Cullman, AL on US Highway 31. Fortunately I was in an old vehicle. It has the scars to prove it was in a hailstorm. The largest hail I saw that night was approximately tennis ball sized, near Hartselle. I wish I had captured the bright green cloud to ground lightning to my north on video. Some areas close to me reported baseball sized hail. The radar at the end is from Dan Satterfield at WHNT 19 in Huntsville describing the storm in the first part of the video. The second report is from ABC 33/40 where my former classmate, Valorie Carter reported on the Cullman storm, which was in the second part of the video.

New weather and old weather

I hope those of you who visit with some degree of regularity will excuse me for not posting as much lately. Things have been fairly quiet weatherwise. I spend a lot of time on the computer (usually in lieu of watching television or watching movies, etc.). I try not to let it interfere with time with my children. Since they are usually with me on a regular schedule, I plan for that. They are the most important aspect of my life, other than my faith itself. Recently they have been with me more than usual, plus we have had other things to deal with.

Anyway, It looks like I will be back with more posting now. The weather looks really interesting this week. Today there is a moderate risk for severe weather in parts of Oklahoma, Texas, Arkansas, and Missouri. Tornado warnings have been issued frequently this morning and damage has been reported northwest of Edmund, OK.

As mentioned previously, tomorrow and Friday continue to look like our best chance of rain and thunderstorms. Most of the energy will be pulling well to our north tomorrow, so I do not expect a major outbreak. But with it being the first day of April, I cannot help but think we may see a few isolated severe storms.

Friday April 4 appears to be our greatest threat of severe weather here since at least the first week of March. A warm front will be pulling north and models are showing some impulses moving along that front may very well trigger some severe weather. It's still a little early to pinpoint, but now it seems that is definitely a day to keep your attention on the weather.

I recently uploaded a video (which my youngest son deemed boring), that only a weather geek would have the patience to sit and watch for all four minutes. Even if you are a CWG, you might not have time for it. Back in May of 1990 I lived in a small house in downtown Tuscaloosa. Those were the days, my friend. Anyway, I saw a fascinating dying severe thunderstorm to my west and northwest as the sun was setting over the city. So what did I do? Duh, you guessed it, I grabbed the video camera.



Have a great week and keep your eyes to the skies!

Friday, March 28, 2008

One of the main reasons...

I'm really looking forward to the MSU Symposium is to maybe see this:


The above picture of Alabama Weather Legend J.B. Elliott is courtesy of James Spann at Alabamawx.com and Chuck Biddinger at servicewithasmile.com

More Photos

It's been pretty quiet around here...

The good news is that we are in the heart of tornado season in Alabama and we are not having any life threatening weather. The bad news is that the weather is boring and dry.

During the first two and one half months of the year, we were holding our own and even making some slight progress in moving toward the end of the most severe drought in recorded history in Alabama. Now we are dipping below our average rainfall again in many parts of the state.

Looking into the future, the models are showing mostly quiet weather during the next 336 hours, or 2 weeks. The pattern is mostly a zonal, or west-to east flow and the main storm track seems to be to our north. This general pattern may occasionally get interrupted. As a matter of fact, there appears to be a chance of a little rain during the next 24 hours. Next week may have two disturbances, one on Tuesday and one on Friday. At this time the late week system shows the most rainfall potential. Another system around April 11th shows a little potential. We'll wait and see on that.

The system due in here at the end of next week may occur during the Mississippi State University's Southeast Severe Weather Symposium. I plan on registering for that today. I am really looking forward to it. I am on a very tight budget right now, but I have wanted to attend this for 7 years and I finally have a chance! I will certainly take a lot of notes and share what I learn here!

Despite the quiet pattern, let's keep our guard up. As mentioned before, we are in the heart of severe weather season in the South. VorTek LLC has published some very interesting scientific findings about geographic placement and frequency of tornadoes. Both Huntsville and Birmingham are in the top 10 cities for tornado frequency in April. Huntsville is actually the most tornado-prone city in the world, based on their research. Since I grew up there, it is no wonder that so many from there, including myself, are nearly obsessed with weather.

The above graphic is from VorTek.

Have a great weekend everyone!

Monday, March 24, 2008

All's quiet on the weather front...


Before I get into the weather, I am compelled mention the passing of a wonderful and Godly lady, Evelyn McDonald. I wrote a tribute here. I sincerely hope you read it! In it I also told about my last visit with her Saturday night, just hours before she passed away. I cannot imagine there being a sweeter person than "Mamaw". One of the things I always loved about her was her folksy sense of humor. I posted a clip of her telling a story that describes exactly what I mean. Pardon me while I preach one thing here: tell people you love them now! Don't wait until tomorrow. I almost did and I am so thankful that I didn't wait for the tomorrow that didn't come! Obituary

Alabama has been enjoying a much needed, and frankly deserved, break from the unsettled weather of the first 10 weeks of 2008. It seems as if we have had a tornado outbreak or snow almost every week for two months now. If you know me at all, you are aware that I can always find something to talk about weatherwise, though. Since late last week the weather can best be surprised as "severe clear". This morning's low was an unseasonably cold 29 at my house but we should be back in the 70's by Wednesday. Our next chance of rain is Saturday. At this time, severe weather does not seem to be likely.

I am really looking forward to attending the 2008 Southeast Severe Storms Symposium at Mississippi State University. I have wanted to attend this event for years but this is the first time that I didn't have a conflict. Usually I have my boys or I have had baseball practice for the team I coached. This year I plan on attending. The agenda looks very interesting. I am particularly interested in the presentations about the February 2008 Super Tuesday Outbreak. It seems like the folks attending know how to have fun and plenty of good food too! I hope to meet some of my weather heroes there and enjoy some great fellowship!

I had a great Easter. I had the opportunity to visit what was an historical event here in the county in which I live. Cullman County is relatively small, and there are churches everywhere you look. But in the 20 years or so that I have been around this area, I have never seen an event quite like I saw Sunday. Daystar Church conducted a special Easter Service at the Wallace State University Coliseum in Hanceville. The place holds 5000 people and it was at over half-full. Daystar, when I first visited 20 years ago, was known as Glory Hill Church of God. The attendance back then was around 50. Evidently God is doing some great things through that ministry. I was extremely impressed and thoroughly enjoyed the service, which incorporated music, preaching, teaching, drama, and video. One of my favorite parts was a little video clip of an 80-something year old lady who talked about the church's history. Kudos to the pastor for profiling her and honoring the faithfulness of her and others from the past!

Thursday, March 20, 2008

Killer Tornado Alley


This is not a distinction we want to have! Nevertheless, it is real and we need to work on changing it. Yes, North Alabama is in possibly one of the worst areas for hard-to-detect tornadoes. Due to high humidity, mountains, trees, and poor visibility, it is extremely difficult to spot tornadoes in this part of the country. That makes them much more dangerous.

Walker Ashley of Northern Illinois University tells us why things are so dangerous here.

Thankfully, Huntsville and North Alabama is blessed with an excellent NWS office and many very committed storm spotters.

My goal is to see this change! We cannot control the weather, but we CAN control our response.

NOAA weather radio will help a lot. If you read this, please buy yourself and every household that you know a weather radio! They can be found for only $29.99 now!

Wednesday, March 19, 2008

1.38 inches of liquid gold today...

This is how it happened...


Loop 9:06 to 9:25


9:20 a.m.

(09:07:58) .82 here so far with a strong storm headed this way

(09:21:01) very heavy rain and a minute-long period of winds gusting to 30 mph within the past 10 minutes

(09:22:17) now up to 1.12" (.30" in the last 15 minutes)

(09:24:29) ponding on the road near the school here

(09:27:53) winds have started gusting again now that the heavy rain has passed

(09:28:08) just heard a clap of thunder as the rain ended

(09:33:21) another brief heavy shower just moved through here after the main line passed by

(09:34:30) still a little thunder here

(09:38:13) 1.26" here.....63 degrees

Strong storms now...severe possible later


At 6:38 lightning began here in Vinemont and continues at 6:42. At 6: 42 heavy rain has begun as the boys and I are getting ready to get in the car (grrrr...).

---

The NWS Birmingham believes that the severe weather threat may hold off until 10 a.m. At 6:37 they issued a mesoscale discussion. Here is an excerpt:
WE ARE STILL WATCHING TRENDS CLOSELY FOR LATER THIS
MORNING...IN THE 15Z TO 17Z TIME FRAME. THERE ARE SOME
INDICATIONS IN BOTH THE NAM AND RUC OF SOME MID LEVEL
COOLING...WHICH COMBINED WITH SURFACE HEATING...MAY
SUFFICIENTLY DESTABILIZE THE ATMOSPHERE TO SUPPORT
CONVECTION. STILL THINKING THE MAIN THREAT WILL BE
THUNDERSTORM WINDS...BUT AT 15Z...RUC13 0-3KM SRH IN
EXCESS OF 300 M2/S2 AND BAND OF MUCAPE OF ABOUT 500
J/KG ROUGHLY ALONG A JASPER/TUSCALOOSA/ UNIONTOWN AXIS
INDICATE THE TORNADO THREAT IS STILL WORTH WATCHING.

Just got up...ready for wild weather


Winds roared last night and continue to roar at 5 a.m. Winds have gusted to 43 mph in my area.

I will be off work and will be storm spotting today.

This just in from the Storm Prediction Center (SPC):

LATEST RUC GUIDANCE IS SUGGESTIVE THAT SUPERCELLS NOW
NORTHEAST OF JACKSON...NEAR THE NORTHERN END OF NARROW
CONVECTIVE LINE...WILL ENCOUNTER INCREASING FORCING IN
EXIT REGION OF A 90 KT SOUTHWESTERLY 500 KT JET STREAK
WITHIN NEXT COUPLE OF HOURS. THIS STILL COULD CONTRIBUTE
TO FURTHER INTENSIFICATION AND INCREASING TORNADIC
POTENTIAL AS CELLS PROGRESS INTO AREAS NEAR/WEST AND
SOUTH OF STARKVILLE AND COLUMBUS BY AROUND 12Z. SLOW
WARMING/ MOISTENING OF THE BOUNDARY LAYER HAS BEEN
OCCURRING ACROSS THIS REGION...

Tuesday, March 18, 2008

Severe threat today and tomorrow in the South


There is a threat of severe weather across the South today and tomorrow. At lunchtime today, the SPC has two PDS (particularly dangerous situation) tornado watches in place to the west of Alabama. Part of the area covered by these watches is under a moderate risk for severe weather.

Tomorrow the threat moves east. I expect storms to approach Alabama in the early morning hours and exit the state around midday. At the moment the SPC has placed Alabama and points to the east under a slight risk for severe weather. I would not be shocked if a part of this area was upgraded to a moderate risk.

The big question with this storm system seems to be instability. Models have been consistently predicting a tremendous amount of sheer but they show very little CAPE (convective available potential energy).

It seems, though the models have been underestimating the fact that with sufficient wind shear, tornadoes can occur with limited instability. I understand that dewpoints were in the 50's when an EF2 tornado struck downtown Atlanta on Friday night, March 14. Of course instability depends not only on temperatures and moisture levels at the surface, but how that contrasts with the air aloft. There needs to be a strong contrast to help provide the upward lift for thunderstorms.

Even with minimal instability, many storms this season have been "low-topped" but produced tornadoes regardless, due to the tremendous amount of shear in the atmosphere.

My "gut" tells me that this will be yet another significant tornado outbreak in parts of the South. Temperatures have been fairly warm over the past few days and with the strong amount of shear, there will be some tornadoes. Of course the $64,ooo question is "where?" No one knows.
One limiting factor for Alabama will be that the storms will be arriving in the morning hours. Of course, storms do not care about the clock, and if conditions are "right" they can occur anywhere at any time.

This is a situation that should be monitored very closely across the South during the next 36 hours!

Monday, March 17, 2008

Crimson Tide Weather

The University of Alabama, my Alma Mater, has participated in several games when weather turned bad.

There was Kenny "Snake" Stabler's famous "run in the mud" against Auburn in 1967.

Snow fell in New Orleans prior to a Sugar Bowl in the 1960's.

There was a tornado warning and a severe thunderstorm during the 1983 Iron Bowl in Birmingham. A tornado was spawned by that same storm just to the northeast of the city.

Coach Bryant's last game in the Liberty Bowl in 1982 was bitterly cold with flurries earlier that day. I had the opportunity to attend that game with my Dad, Uncle, cousin, and a friend. Thanks to my Dad!

The Liberty Bowl in Memphis in (I think) 1959 was cold too.

I seem to remember a 3-0 game against LSU in Baton Rouge in the 1970's that was played in fog and drizzle. I remember listening on radio as I shot baskets in my driveway at night.

In 2003 a strong thunderstorm delayed the Alabama v Arkansas game in Tuscaloosa. There was a lot of lightning with that storm.

There have been others. Plus extreme heat is always an issue in those September games.

More from Georgia

There continues to be a lot of talk still about this weekend's tornado outbreak in Alabama, Georgia, and the Carolinas. Most of the buzz continues to revolve around the EF2 tornado that struck downtown Atlanta.

Slideshow of damage to Georgia Dome
from AtlantaFalcons.com

Atlanta Meteorologist Josh Johnson's photos

Talkweather.com forum discussion
of Georgia Dome Tornado

Video: "The shot that saved lives"



Talkweather.com discussion about "the shot that saved lives".

WeatherBrains


Note: This post was originally published January 29, 2008. If you enjoy weather and want to learn more, this is a must listen! Last week, on March 10, Episode 111, James Spann and J.B. Elliott mentioned me in relation to my question about the closet ever proximity between a tornado and snow.

---

It is way past time that I mention one of my favorite weather resources, WeatherBrains. WeatherBrains is a weekly netcast about all things weather, by a bunch of self-proclaimed weather geeks, led by ABC 33/40 Chief Meteorologist James Spann from Birmingham, Alabama.
WeatherBrains has been running weekly programs now for about two years and I have not missed one yet. This morning was the 105th episode. In addition to Spann, regulars include Kevin Selle, Brian Peters, J.B. Elliott, Bill Murray, and David Black.

According to their website, WeatherBrains “is a weekly netcast for weather enthusiasts. Originating from The Weather Company in Birmingham, Alabama, the WeatherBrains crew takes an in depth look at all sides of the weather scene. Interviews with news makers, detailed explanations of research, weather history, as well as how people deal with the weather, all with good humor and good fun. New shows are posted each Tuesday.”

If you are reading my blog you may have already heard of this program you may already be a listener, but if you are not, I highly recommend that you give it a try.

I can’t resist mentioning that I (yes, little ol’ me) have been mentioned on a few episodes. In Episode 58, the guys discuss the March 1, 2007 Enterprise, Alabama tornado. James Spann mentions some statistical data I sent to him about tornadoes and schools. In Episode 100 on December 24, 2007 a joke I shared was read at the email segment toward the end of the program. Also my idea about a new weather channel was mentioned in Episode 103 on January 14, 2008. I have asked a question on one or two other occasions that was addressed. In today’s episode, Brian Peters mentions Snowflake Bentley, which he read about on this blog recently.

Enough of the self-aggrandizement. This is a really educational and fun show. It’s great to listen to while working on other things on your computer and it is also available to Ipod users.

March 15, 2008 Tornado Outbreak

There were two tornadoes officially confirmed by the National Weather Service in Alabama on Saturday March 15, 2008; one in Blount County and one in Cherokee County.

The NWS in Birmingham rated the Blount County Tornado an EF2. According to the NWS, it touched down 5 miles southeast of Oneonta at 9:50 a.m. near Highland Lake and traveled northeastward, paralleling County Road 12 until it lifted near US 231 after being on the ground for six miles. A severe thunderstorm warning was issued at about 9:20 and a tornado warning was issued at 9:46 by the NWS Birmingham. The tornado was 675 yards wide at it's widest point. Dozens of chicken houses were damaged or destroyed. At least 25 homes received major damage. A few mobile homes were damaged and one was destroyed. At least six cows were killed by flying debris. A few feed silos were damaged and one was rolled one half mile by the tornado.

Photos of Blount County damage

Blount County radar shots between 9:21 and 9:58:






Blount County tornado coverage by Jason Simpson



The Cherokee County tornado was also rated an EF2 by the NWS Birmingham. This tornado touched down 4 miles north of Piedmont just before 11 a.m. A tornado warning was issued at 10:31 for Cherokee County. It was on the ground for 3 miles and was only 50 yards wide at it's widest point. Three homes were damaged by the tornado. This tornado passed within 1/2 mile of the terrible 1994 tornado that struck the Goshen United Methodist Church during Palm Sunday services.

Cherokee County damage photos.

Here is a photo of the Cherokee County tornado posted by James Spann at Alabamawx.com. This photo was taken by Shea Rowland near Spring Garden, Alabama.

Cherokee County tornado coverage by ABC 33/40 Meteorologist Jason Simpson



As the storm passed over St. Clair County this video was taken.

Awakend by storms!

On the morning of Saturday March 15 there were three bands of thunderstorms that moved through my area. These three storms occurred at 2:35, 5:49, and 8:49.

Fellow blogger Nathan, from Wisconsin, was kind enough to send me several radar capures of the first line as it moved though my area. I had taken a nap and was awakened by thunder as the storms approached. My boys all slept right through it! I was too groggy to post anything at the time so I appreciate him sharing these shots. Here are two of them.


2:31 a.m.


2:35 a.m.

I was awake enough to capture the one below, but I wish that I had been alert enough to pick up my camera or video camera!



There were two more lines:

5:49


8:49

Friday, March 14, 2008

Strong to severe storms today and tonight



See an excellent discussion about Alabama's weather situation by Tim Coleman here. Storms are rolling through as I write this, but with a temperature of 52, the air is not unstable enough to produce severe weather. The story may change this evening, especially if we get much sunshine.

Stay close to a source of weather today.

Sunday, March 09, 2008

ABC 33/40 viewer photos of 3/8/08 Alabama snow

ABC 33/40 Viewer Photos of 3/8/08 Alabama Snow. Twenty four Alabama counties were represented in these photos. It was a day of pure fun for kids of all ages and I think that is captured in these photos. Enjoy!

Saturday, March 08, 2008

Monte Sano snow

I took these photos this morning at Monte Sano State Park in Huntsville, Alabama.


Created with Admarket's flickrSLiDR.

Wreck on I-65 in Homewood, AL captured live








Snow!






Light snow accumulations have occurred throughout North Alabama.

Amounts are generally between a dusting and one inch.

Many photos from 33/40

Birmingham AL DOT Cameras

Interstate 65 closed in Downtown Birmingham

Memorial Pkwy closed in HSV

Friday, March 07, 2008

Snow updates continue...

8:37 - Michelle asked me to pass this report on: MMiklik, I'm here in HSV we are getting some a good heavy freezing rain/sleet

8:41 Snow flurries in NE Huntsville...33

8:44
moderate sleet in NE HSV began during the last 30 seconds

8:49 temp hit 32 in NE HSV

9:00
NE HSV lgt sleet/frz rain....32...sleet beginning to accum on windshield

Brian Peters live

9:09
Northport 39.2 and light light snow/mist

Snow begins in Alabama


6:15 Columbus Nexrad

Light Snow/drizzle being reported in the far northwest part of Marion County just after 6 p.m.
At 6:15 in Huntsville...light drizzle and 36.

Radar indicates that snow has entered western Franklin, Colbert, and Lauderdale counies as of 6 p.m.

At 7:10...
light snow falling on the west side of Hamilton

8" of snow in Marianna, AR

3" in downtown Memphis

7:20
Snowing in Millport-Lamar...35 with light wind from NW.

7:20
light snow falling in North Fork 8 miles nne of Hamilton

7:24
tornado warning - metro Atlanta

7:33 snowing good in Hamilton now big flakes

7:45 36 and Sleet in Fayette

7:45 34 in Millport with a pretty good snow shower, flakes getting bigger


7:04 to 7:53 Columbus Nexrad shows snow is increasing

8:00 Great post about current synoptics from meteorologist Tim Coleman

8:08 Temp is 33 in NE Huntsville; light dusting on cars in Hamilton

8:30 Hazardous wx outlook from NWS Huntsville:
"A MAJOR WINTER STORM WILL AFFECT THE TENNESSEE
VALLEY TONIGHT...
THROUGH MIDDAY SATURDAY...BRINGING SIGNIFICANT SNOWFALL AND GUSTY
NORTHERLY WINDS TO THE REGION. PRECIPITATION HAS ALREADY CHANGED
OVER TO SNOW ACROSS NORTHWEST ALABAMA.

AS THE COLD AIR CONTINUES TO FILTER IN FROM THE NORTHWEST
OVERNIGHT...THE RAIN AND SLEET ACROSS NORTH CENTRAL ALABAMA WILL
CHANGE OVER TO ALL SNOW. ONE TO THREE INCHES OF SNOWFALL WILL BE
POSSIBLE OVER MUCH OF THE TENNESSEE VALLEY...WITH ACCUMULATIONS
POSSIBLY REACHING FOUR TO FIVE INCHES IN PORTIONS OF NORTHWEST
ALABAMA."

Winter Storm Warning

The Huntsville NWS has placed North Alabama under a Winter Storm Warning for tonight and tomorrow morning. Accumulations will be greatest in Northwest Alabama, higher elevations of Northeast Alabama, and Tennessee. Here is part of the warning text and then a part of the forecast discussion:
HEAVIER CONVECTIVE SNOWBANDS MAY AFFECT THIS
REGION AS AN UPPER LEVEL LOW MOVES ALMOST
DIRECTLY OVERHEAD TONIGHT. AS A RESULT...
SNOWFALL ACCUMULATIONS OF TWO TO THREE INCHES
ARE POSSIBLE ACROSS NORTHWEST ALABAMA.


OUR THINKING IS THAT 2-3IN SEEMS LIKELY IN NW
AL...AROUND
2 IN THE HSV METRO...AND 2-4 IN
SRN MID TN/JACKSON CO. WILL TREND A BIT LOWER
IN OUR SE WHERE THE SNOW
CHANGEOVER WILL BE
DELAYED THE LONGEST...AND HIGHER IN
SOME OF
THE HIGHER ELEVATIONS WHERE
NWLY FLOW
UPSLOPING
WILL AID ACCUMULATIONS. THE BIGGEST
ISSUE WILL BE
MESOSCALE BANDING AS NOTED
EARLIER...AS THE 12Z
NAM DOES SHOW A DECENT
AREA OF POTENTIAL
VORTICITY AND MID-LVL
DEFORMATION MOVING INTO THE REGION JUST
BEHIND THE SNOW
CHANGEOVER /AND THIS IS
BACKED UP BY OBSERVED TRENDS TO
OUR WEST/.
IF THIS WERE TO OCCUR LOCALLY...OUR TOTALS

COULD VERY WELL BE ON THE LOW SIDE.

Mesoscale Discussion from SPC...


MODEL FORECASTS DO NOT APPEAR TO HAVE A HANDLE
ON WEAK ELEVATED INSTABILITY WHICH HAS CONTRIBUTED
TO ISOLATED TSTM DEVELOPMENT. HOWEVER...MODIFYING
FOR COOLER MID-LEVEL TEMPERATURES IN 12Z SHV RAOB
WOULD SUGGEST THERE IS SUFFICIENT INSTABILITY AND
CHARGE SEPARATION TO GENERATE LIGHTNING. THUS...
LOCALIZED CONVECTIVE BURSTS OF INTENSE SNOW/REF
2.5 IN PER HR OBSERVED RATE IN JEFFERSON COUNTY AR
AT 19Z/...OUGHT TO CONTINUE.

Winter Storm Watch / Heavy Snow Warning

At Noon, Huntsville and Birmingham NWS offices continue to predict a significant (for the South) winter storm to affect North and Central Alabama tonight and tomorrow evening. If anything, the confidence level is increasing with this forecast.

Huntsville continues the Winter Storm Watch for its entire county warning area. They are predicting 1 to 3 inches at this time with up to 5 inches in extreme Northwest Alabama and also in higher elevations. Later this afternoon portions of the area may be placed under a warning.

Birmingham has issued a Heavy Snow Warning for Marion, Lamar, Fayette, Winston, and Walker, Blount, Etowah, and Cherokee Counties. They are expecting accumulations up to 2.5 inches in these areas between 6 this evening and 10 tomorrow morning.

Birmingham has also issued a Heavy Snow Warning for numerous other counties in Central Alabama. Cities included in this warning include: Anniston, Tuscaloosa, Birmingham, Talladega, Moundville, Clanton, Demopolis, Selma, Prattville, Auburn, Montgomery, Troy, and Phenix City. Noth of the I-20 corridor accumulations will be up to 1.5" and accumulations of up to one-half an inch may occur in the southern part of the warned area.

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1221 PM CST FRI MAR 7 2008

...WINTER WEATHER LIKELY ACROSS THE TENNESSEE VALLEY TONIGHT...

.COLD AIR FILTERING INTO THE TENNESSEE VALLEY...COMBINED WITH AN
UPPER LEVEL STORM SYSTEM MOVING ACROSS THE AREA...WILL BRING SNOW
TO THE REGION TONIGHT. A BRIEF WINTRY MIX IS POSSIBLE AS THE
PRECIPITATION CHANGES FROM RAIN TO SNOW.

LAUDERDALE-COLBERT-FRANKLIN AL-LAWRENCE-LIMESTONE-MADISON-MORGAN-
JACKSON-MOORE-LINCOLN-FRANKLIN TN-
INCLUDING THE CITIES OF...FLORENCE...MUSCLE SHOALS...
RUSSELLVILLE...MOULTON...ATHENS...HUNTSVILLE...DECATUR...
SCOTTSBORO...LYNCHBURG...FAYETTEVILLE...WINCHESTER
1221 PM CST FRI MAR 7 2008

...WINTER STORM WATCH REMAINS IN EFFECT FROM 6 PM CST THIS
EVENING THROUGH SATURDAY MORNING...

A WINTER STORM WATCH REMAINS IN EFFECT FROM 6 PM CST THIS EVENING
THROUGH SATURDAY MORNING.

RAINFALL THIS EVENING IS EXPECTED TO CHANGE OVER TO ALL SNOW
DURING THE EVENING HOURS. TOTAL SNOWFALL ACCUMULATIONS OF 1 TO 3
INCHES ARE POSSIBLE...WITH ACCUMULATIONS UP TO 5 INCHES IN EXTREME
NORTHWEST ALABAMA AND AT HIGHER ELEVATIONS. LIGHT SNOW IS EXPECTED
TO PERSIST SATURDAY MORNING BEFORE TAPERING OFF SATURDAY
AFTERNOON.

PORTIONS OF THIS WATCH ARE LIKELY TO BE UPGRADED TO A WINTER STORM
WARNING LATER THIS AFTERNOON.

ROADS...BRIDGES...AND OVERPASSES IN THE WATCH AREA MAY BECOME
SLICK AND HAZARDOUS. EXERCISE EXTREME CAUTION IF TRAVEL IS
NECESSARY.

REMEMBER...A WINTER STORM WATCH MEANS CONDITIONS ARE FAVORABLE
FOR A HAZARDOUS WINTER WEATHER EVENT IN AND CLOSE TO THE WATCH
AREA.

STAY TUNED TO NOAA WEATHER RADIO OR OTHER LOCAL MEDIA OUTLETS FOR
FURTHER DETAILS OR UPDATES FROM THE NATIONAL WEATHER SERVICE IN
HUNTSVILLE.

Winter Storm Watch


From the NWS Huntsville

A Winter Storm Watch has been issued by the National Weather Service for North Alabama. I am predicting that accumulations of 2-4 inches are possible throughout the Tennessee Valley. The northwest part of the state may receive the greatest accumulation. The Winter Storm Watch is in effect from 6 p.m. until Noon tomorrow.

Models have consistently shown snow beginning in the NW corner of the state around 6 p.m. and exiting the state to the northeast tomorrow around midday.

THE SPECIFICS of this forecast could change. There are so many variables to consider when predicting snow in Alabama. Some accumulation is very likely in North Alabama. In addition, most of the state could see snowflakes overnight.

Please visit again for more details on this developing situation.


Strong storms blowing through



At 6 a.m. 38.7 degrees rain .60" so far

Winter weather map discussion

Wednesday, March 05, 2008

Snow in Alabama?

The GFS is showing a decent chance of snow in Alabama Friday night and Saturday Morning. This could even result in some accumulation, especially in the Tennessee Valley. The NAM is keeping the frozen precipitation mostly to the north of Alabama.

This is definitely one to watch.

The images below are from the 6 a.m. run of the GFS showing precipitation type. The last two images show the amount of precipitation (liquid equivalent). Notice how the NAM has much less snow accumulation in Alabama in comparison to the GFS. The snow accumulation map is the upper right map.

Tuesday, March 04, 2008

Two confirmed tornadoes in Alabama (so far)

Last night's storm system produced two confirmed tornadoes in Alabama overnight, according to the National Weather Service Office in Birmingham.

Eutaw, Greene Co, AL - NWS storm survey reported EF-1 tornado at 12:49 a.m. on March 4, 2008. Twenty five homes damaged, one home destroyed, and four homes sustained major damage. Hundreds of trees were snapped or downed. The path length was 5.6 miles.

4 miles NW of Samantha, Tuscaloosa Co, AL - NWS storm survey reported an EF-1 tornado which touched down just south of County Road 38 near Old Fayette Road. The path length was three quarters of a mile. Six homes were damaged, one home was heavily damaged, and several hundred trees snapped or downed.


Radar for Greene County at 12:49 a.m.

Photos of tornado damage in Eutaw in Greene County, from Alabamawx.com

Photos of tornado damage
in Samantha in Tuscaloosa County, from ABC 33/40, taken by Skywatcher Curtis Smith.

Monday, March 03, 2008

Tornado Watch

Storms continue to approach

There are still lots of tornado warnings to the west in Mississippi as of 9:30. A tornado watch will likely be issued soon for parts of Alabama, south of Tuscaloosa and Birmingham.


   MESOSCALE DISCUSSION 0336
NWS STORM PREDICTION CENTER NORMAN OK
0859 PM CST MON MAR 03 2008

AREAS AFFECTED...ERN MS...SWRN AL...WRN FL PANHANDLE

CONCERNING...TORNADO WATCH 92...

VALID 040259Z - 040400Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 92 CONTINUES.

...SEVERE THREAT WILL INCREASE ACROSS ERN MS INTO WRN/SRN AL INTO
THE FL PANHANDLE BY MIDNIGHT. TORNADO WATCH MAY BE REQUIRED BY
04Z...

MODIFIED GULF AIRMASS HAS RETURNED ACROSS SERN LA INTO SERN MS AND
EXTREME SRN AL...PER SFC DEW POINTS INTO THE MID 60S. THIS MOISTURE
RETURN WILL BE INSTRUMENTAL IN BOOSTING INSTABILITY FOR ROBUST
UPDRAFT DEVELOPMENT. ADDITIONALLY...STRONGER FORCING WILL SOON
SPREAD ATOP THIS HIGHER THETA-E AIRMASS WHICH WILL ENHANCE
ORGANIZATIONAL POTENTIAL. OVER THE LAST HOUR OR SO...CONVECTION
SOUTH OF I-20 IN MS HAS GRADUALLY INCREASED ALONG ADVANCING FRONTAL
ZONE. THIS TREND SHOULD CONTINUE AND A MORE FOCUSED SQUALL LINE
WILL LIKELY EVOLVE OVER THE NEXT FEW HOURS. NEEDLESS TO
SAY...STRONG LOW-MID LEVEL SHEAR WILL SUPPORT SUPERCELL
DEVELOPMENT...HOWEVER THE DOMINANT STORM MODE MAY BE LINEAR IN
NATURE...ALTHOUGH BOW-TYPE STRUCTURES MAY EVOLVE WITHIN THE LINE.
ISOLATED TORNADOES ARE ALSO POSSIBLE GIVEN THE INCREASE IN MOISTURE
AND STRONG SHEAR.

Storms are firing in MS


At 2:00 p.m. The SPC updated the moderate risk area to include much of southern and western Alabama, all of Mississippi and eastern Louisiana. A tornado watch is also in effect until 11 p.m. for practically all of Mississippi.


4:18 p.m. CT regional radar

Numerous tornado warnings have been issued in South Mississippi.

Severe weather will be approaching West Alabama by around 10 or 11 p.m. this evening.

Here is some information from the Huntsville NWS in a Special Weather Statement issued at 3:25:
A SQUALL LINE WITH EMBEDDED STRONG TO SEVERE THUNDERSTORMS WILL MOVE
ACROSS THE MISSISSIPPI RIVER BY THE EARLY EVENING. THIS SQUALL LINE
SHOULD REACH NORTHWEST ALABAMA AROUND MIDNIGHT TO 2 AM...THE
INTERSTATE 65 CORRIDOR 2 AM TO 4 AM...AND THEN AREAS FROM BRIDGEPORT
THROUGH FORT PAYNE AROUND 5 AM TO 7 AM. THE PRIMARY SEVERE WEATHER
THREAT CONSISTS OF DAMAGING WINDS IN EXCESS OF 60 MPH. BRIEF ISOLATED
TORNADOES MAY ALSO DEVELOP WITHIN STRONGER THUNDERSTORMS ALONG THE
LEADING EDGE OF THE SQUALL LINE.
Stay tuned for more updates.

A quick post...

Severe weather remains a threat in Alabama during the overnight hours. Parts of southern and western Alabama are under a moderate risk from the SPC.

Wind fields with this storm system continue to look impressive. The big question continues to be the dewpoints.

Much more to come later...

SPC, GFS, NAM



   DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1157 PM CST SUN MAR 02 2008

VALID 031200Z - 041200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS SERN AR...MUCH OF LA AND
MS...AND INTO EXTREME WRN FRINGES OF AL...

...THERE IS A SLGT RISK OF SVR TSTMS FROM E TX ACROSS THE LOWER AND
MID MS VALLEY INTO THE TN VALLEY/CENTRAL GULF COAST REGION...

...SYNOPSIS...
SIGNIFICANT SEVERE WEATHER EVENT CENTERED INVOF THE LOWER MS VALLEY
IS FORECAST THIS PERIOD -- INCLUDING THE POTENTIAL FOR
WIDESPREAD/DAMAGING WINDS AND SEVERAL/POTENTIALLY-SIGNIFICANT
TORNADOES.

LARGE MID-LEVEL TROUGH -- INITIALLY CONSISTING OF A PHASED NRN AND
SRN STREAM SYSTEM -- SHOULD EXTEND FROM MN SWWD ACROSS THE CENTRAL
PLAINS INTO NM AT THE START OF THE PERIOD. THIS TROUGH IS FORECAST
TO SHIFT EWD ACROSS THE PLAINS/UPPER MS VALLEY WITH TIME THROUGH THE
FIRST HALF OF THE PERIOD. DURING THE SECOND HALF OF THE
PERIOD...THE NRN STREAM FEATURE IS FORECAST TO ACCELERATE EWD ACROSS
THE GREAT LAKES AND EVENTUALLY INTO QUEBEC...WHILE THE SRN STREAM
FEATURE EVOLVES INTO A CLOSED LOW -- FORECAST TO MOVE INTO AR BY
04/12Z. THE SRN STREAM FEATURE WILL BE ACCOMPANIED BY A VERY
STRONG/INTENSIFYING DEEP-LAYER WIND FIELD...INCLUDING A 100-PLUS KT
SSWLY H5 JET STREAK.

AT THE SURFACE...COLD FRONT WILL SWEEP ACROSS THE MIDWEST AND INTO
THE NORTHEAST...WHILE A SURFACE LOW DEVELOPS ON THE TRAILING PORTION
OF THIS FRONT AS THE SRN STREAM FEATURE ALOFT STRENGTHENS. THIS LOW
-- FORECAST INVOF SRN AR/NRN LA/W CENTRAL MS AT 04/00Z -- IS
EXPECTED TO MOVE NEWD INTO MIDDLE TN BY THE END OF THE PERIOD AS
COLD FRONT SWEEPS ACROSS THE LOWER MS VALLEY AND INTO THE CENTRAL
GULF COAST REGION.

...E TX EWD ACROSS THE LOWER AND MID MS VALLEY INTO SRN KY/TN/NWRN
GA/AL/WRN AND CENTRAL FL PANHANDLE...
STORMS SHOULD BE ONGOING ALONG/AHEAD OF THE ADVANCING COLD FRONT AT
THE START OF THE PERIOD -- FROM SERN MO/AR SWWD ACROSS NERN AND INTO
CENTRAL TX. AS SRN STREAM UPPER FEATURE STRENGTHENS...SURFACE LOW
SHOULD DEVELOP/MOVE NEWD ALONG THE FRONT ACROSS E TX...ALLOWING THE
FRONT TO MOVE QUICKLY SEWD ACROSS TX. BY EARLY AFTERNOON...SLY FLOW
WITHIN THE WARM SECTOR FLOW ADVECTING LOW-LEVEL MOISTURE NWD...ALONG
WITH SOME HEATING...WILL RESULT IN MODEST DESTABILIZATION /AOB 1000
J/KG/...LIMITED BY WEAK LAPSE RATES ALOFT.

DESPITE THIS...VERY STRONG DEEP-LAYER WIND FIELD -- EXPECTED TO VEER
SUBSTANTIALLY AND INCREASE RAPIDLY WITH HEIGHT -- WILL RESULT IN
DEEP-LAYER SHEAR VERY FAVORABLE FOR SEVERE STORMS...AND LOW-LEVEL
SHEAR HIGHLY-SUPPORTIVE OF TORNADOES. THUS...EXPECT SEVERE THREAT
TO INCREASE THROUGH THE LATE MORNING INTO THE AFTERNOON. BY MID
AFTERNOON...A WELL-DEFINED LINE OF STORMS SHOULD BE MOVING TOWARD
THE LOWER MS RIVER...WITH AT LEAST SOME POTENTIAL FOR ISOLATED
STORMS DEVELOPING AHEAD OF THE MAIN CONVECTIVE LINE. WHILE LIMITED
DEGREE OF INSTABILITY RAISES SOME QUESTION AS TO THE EXTENT OF
ISOLATED/PRE-FRONTAL CELLULAR DEVELOPMENT...ATTM IT APPEARS THAT THE
POTENTIAL IS GREAT ENOUGH TO SUGGEST THE POSSIBILITY OF
MULTIPLE/POTENTIALLY-DAMAGING TORNADOES. TORNADOES WILL ALSO BE
POSSIBLE WITHIN THE MAIN CONVECTIVE LINE...THOUGH THE PRIMARY THREAT
WITH THIS LINE WILL LIKELY BE WIDESPREAD/POSSIBLY SIGNIFICANT WIND
DAMAGE.

AFTER DARK...A SLOW DECREASE IN INSTABILITY IS EXPECTED...BUT VERY
STRONG/VEERING WIND FIELD WILL LIKELY CONTINUE TO SUPPORT A THREAT
FOR DAMAGING WINDS AND TORNADOES. CONVECTION SHOULD SHIFT ACROSS MS
AND WRN PORTIONS OF TN AND KY DURING THE EVENING...AND THEN SPREAD
ACROSS THE REMAINDER OF KY...TN...AL...AND INTO THE FL PANHANDLE
THROUGH THE END OF THE PERIOD. WHILE THE SEVERE THREAT SHOULD
SLOWLY DECREASE INTO THE EARLY MORNING...SOME SEVERE POTENTIAL IS
EXPECTED TO PERSIST THROUGH THE END OF THE PERIOD.


Latest GFS output for Midnight tomorrow.


Latest NAM output for Midnight tomorrow.

Great summary from Tim Coleman at Alabamawx.com

Sunday, March 02, 2008

From Jackson, MS and Huntsville NWS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
835 PM CST SUN MAR 2 2008

...SIGNIFICANT SEVERE WEATHER OUTBREAK MONDAY LATE AFTERNOON
/EVENING INCLUDING TORNADOES...

.DISCUSSION...THINGS STILL ON TRACK FOR MON AFTERNOON/
EVENING AND LOOK VERY OMINOUS! NEW 00Z NAM HAS ARRIVED AND
IS NEARLY IDENTICAL TO THE PREV RUNS ON TIMING AND CONVECTIVE
EVOLUTION. IF ANY THING...IT IS A TAD STRONGER AS THE SFC LOW
IS DEEPER...THUS MAKING THE LLJ A TAD STRONGER. I`M NOT SURPRISED
THE SFC LOW IS A BIT DEEPER AND FULLY EXPECT THE 00Z GFS TO
FOLLOW SUIT. THIS IS TOO MUCH OF A POWER HOUSE SYSTEM TO KEEP
PRESSURE >1006-1009MB. I CAN EVEN SEE PRESSURE GET LOWER THAN
WHAT THE NAM/EURO ARE ADVERTISING WITH VALUES CLOSER TO 1000MB
ACROSS THE CWA.

I`M BECOMING VERY CONCERNED ABOUT THE 21-00Z WINDOW AS THE
NAM/GFS ALL INDICATE PRE-FRONTAL CONVECTION. YOU CAN VISUALIZE
THINGS BETTER WITH THE NAM B/C OF THE 21Z TIME STEP. THE MAIN
THING IS THEY BOTH INDICATE THE DEVELOPMENT OF SUPERCELLS IN
ADVANCE OF THE MAIN SQUALL LINE/FRONT AND MAY ACTUALLY BECOME A
LARGE FAMILY OF SUPERCELLS
THAT RAPIDLY TRACK NE INTO/ACROSS THE
CWA. I DID A LOCAL SVR WX CHECKLIST FOR MLU AT 21 USING GFS BUFR
SOUNDINGS AND GOT WHAT AMOUNTS TO THE HIGHEST RANKING (EXTREME)
WHICH IS RARE TO ACHIEVE (FEB 5 2008 ALSO HIT IT) WHICH HISTORICALLY
SUPPORTS A SIG RISK OF A HIGH END EVENT
WITH SIG TYPE TORNADOES.
WHAT ALSO GETS ME CONCERNED IS WHERE THE STORMS INITIATE...SW TO
CENTRAL LA. THEY THEN WILL QUICKLY TRACK ALMOST NNE INTO OUR W/SWCWA.
THIS GIVES ANY SUPERCELL TIME TO MATURE AND BECOME LONG LIVED.
THOSE ARE THE WORST AS FEB 5 HAS SHOWN. I CAN REALLY SEE A CORRIDOR
ALONG THE TRACE AND ABOUT 50 MILES EITHER SIDE OF THAT BEING EXTREMELY
FAVORABLE FOR SIG TORNADOES BETWEEN 4-9 PM. MON HAS THE POTENTIAL
TO BE A HISTORIC TYPE SVR WX DAY AND ALL NEED TO BE WX CONSCIOUS.

---

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
948 PM CST SUN MAR 2 2008

ALZ001>010-016-TNZ076-096-097-031200-
LAUDERDALE-COLBERT-FRANKLIN AL-LAWRENCE-LIMESTONE-MADISON-MORGAN-
MARSHALL-JACKSON-DE KALB-CULLMAN-MOORE-LINCOLN-FRANKLIN TN-
INCLUDING THE CITIES OF...FLORENCE...MUSCLE SHOALS...
RUSSELLVILLE...MOULTON...ATHENS...HUNTSVILLE...DECATUR...
GUNTERSVILLE...SCOTTSBORO...FORT PAYNE...CULLMAN...LYNCHBURG...
FAYETTEVILLE...WINCHESTER
948 PM CST SUN MAR 2 2008

...SEVERE WEATHER LIKELY ACROSS THE TENNESSEE VALLEY LATE MONDAY
NIGHT INTO TUESDAY MORNING...

A STRONG STORM SYSTEM AND COLD FRONT WILL BRING THE
POSSIBILITY OF STRONG TO SEVERE THUNDERSTORMS ACROSS THE
TENNESSEE VALLEY BY MONDAY NIGHT AND INTO TUESDAY MORNING. AT
THE MOMENT...THE ATMOSPHERE LOOKS TO STABLE FOR ANY WIDESPREAD
THUNDERSTORM ACTIVITY MONDAY AFTERNOON.

THE BEST TIME FOR SEVERE WEATHER WILL BE BETWEEN 10 PM AND 11 PM
OVER NORTHWEST ALABAMA...AROUND MIDNIGHT IN THE HUNTSVILLE AREA
AND MIDNIGHT TO 2 AM OVER NORTHEAST ALABAMA AND PORTIONS OF
SOUTHERN MIDDLE TENNESSEE. THE MAIN SEVERE WEATHER THREATS WILL BE
DAMAGING WINDS...HAIL UP TO THE SIZE OF QUARTERS AND LOCALIZED
HEAVY RAIN. THERE IS ALSO THE POSSIBILITY OF ISOLATED TORNADOES.

PERSONS ACROSS THE TENNESSEE VALLEY SHOULD MAKE PREPARATIONS NOW FOR
THIS LIKELY SEVERE WEATHER EVENT. TAKE TIME TO REVIEW YOUR SEVERE
WEATHER SAFETY PLANS...AND INSURE YOUR NOAA WEATHER RADIO IS WORKING
PROPERLY. SEVERE THUNDERSTORM OR TORNADO OCCURRENCES DURING THE
OVERNIGHT HOURS ARE ESPECIALLY DANGEROUS.

STAY TUNED TO NOAA WEATHER RADIO OR YOUR FAVORITE MEDIA OUTLET FOR
THE LATEST WEATHER INFORMATION REGARDING THIS SEVERE WEATHER
EVENT. YOU CAN ALSO GET THIS INFORMATION FROM THE NATIONAL WEATHER
SERVICE HUNTSVILLE WEBSITE AT: WWW.WEATHER.GOV/HUNTSVILLE.

Severe threat ahead for Alabama


The above image is the outlook for Monday March 3 from the Storm Prediction Center. This is the outlook that they issued early this morning.


This is the probability map associated with the above outlook. The greatest risk of severe weather in Alabama, according to the SPC, is in West Alabama, generally along and west of Interstate 65.


This is the latest from the GFS model that was issued at midnight last night. The 12z (or 6 a.m. CT update should be available soon).



The above is the most recent NAM output, issued at 12z (6 a.m.) today. As you can see, the NAM projects that this storm will be progressing slower and will arrive later than the GFS.

It now appears that we might be looking at another nighttime severe weather threat on Monday night. The projections for the wind field with this storm system are very impressive. The biggest question is whether instability will be enough to cause supercells to develop ahead of the main squall line. If they do, wind shear will be sufficient to cause the storms to rotate and produce tornadoes.

The timing of this event, if it moves in overnight, might serve to inhibit instability.

What to look for:

1. Dewpoints on Monday - If we see dewpoints above 60, there may be enough instability for a few tornadoes. If dewpoints make it to near 65, this may be a major tornado outbreak.

2. Sunshine on Monday - The more daytime heating we receive Monday, the more likely our dewpoints will be high enough to create the instability needed for convection ahead of the main line. Cloudiness on Monday would limit dewpoints, instability, and the threat for tornadoes.

3. Air temperature aloft. Part of the instability question has to do with temperatures aloft. Dewpoints will not have to be as high at the surface if the air aloft is cold enough. On the otherhand, if there is enough modified, warmer air aloft, dewpoints will have to be higher to provide the instability needed.

As I write, the 12z GFS data has rolled in.

This has the potential to be a very dangerous night time event. Please purchase a NOAA weather radio and be prepared to receive warnings Monday night! More to come on this developing situation.



From the SPC:
PRE-FRONTAL AIR MASS WILL DESTABILIZE THROUGH THE PERIOD OWING
LARGELY TO A MOISTENING BOUNDARY LAYER WITH DEWPOINTS INCREASING
THROUGH THE 60S FROM THE SABINE RIVER VALLEY EWD ACROSS MUCH OF THE
LOWER MS VALLEY INTO THE CNTRL/ERN GULF STATES. THE STRONGEST
INSTABILITY IS FORECAST ACROSS SERN TX...LA AND CNTRL/SRN MS WHERE
RICHER BOUNDARY LAYER MOISTURE WILL COMBINE WITH DIABATIC HEATING TO
SUPPORT MLCAPES OF 1000-1500 J/KG. INSTABILITY WILL TEND TO
DECREASE WITH NWD AND EWD EXTENT ACROSS THE REGION.

VERTICAL SHEAR WILL BE QUITE STRONG /MOST NOTABLY ALONG THE
MIGRATORY LLJ AXIS/ WHERE EFFECTIVE BULK SHEAR AND SRH VALUES SHOULD
EXCEED 45-50 KT AND 300-400 M2/S2 RESPECTIVELY. THUS POTENTIAL WILL
EXIST FOR SUPERCELLS /SOME LONG-LIVED/ EMBEDDED WITHIN LARGER-SCALE
QLCS AND/OR IN ADVANCE OF MAIN CONVECTIVE SYSTEM WITH A THREAT OF
SIGNIFICANT TORNADOES ALONG WITH HAIL. CORRIDORS OF DAMAGING WIND
ALSO APPEAR LIKELY /NAMELY WITH ANY LARGER-SCALE BOWS/ GIVEN
STRONG...AMBIENT WIND FIELDS AND RESULTANT FAST STORM MOTIONS.
From NWS Birmingham:

HE BIG SHOW COMES MONDAY NIGHT. SPC HAS US IN A SLIGHT RISK
AREA...ALTHOUGH WE ALSO NOTE THAT THE HATCHED 30 PERCENT AREA
EXTENDS ARE FAR EAST AS BHM AND ALMOST TO SELMA...AND THE MDT RISK
(AND THE HATCHED 45 PERCENT) IS RIGHT ON OUR DOORSTEP. THE
SYNOPTIC PATTERN PREDICTED BY THE MODELS CERTAINLY SUGGEST A
FAIRLY HIGH POTENTIAL FOR SEVERE WEATHER. MOISTURE AND LIFT WILL
NOT BE LACKING MONDAY NIGHT...AND A 70+ KNOT LOW LEVEL JET CANNOT
BE IGNORED. THERE`S SHEAR A-PLENTY...BUT THE MODELS ONCE AGAIN
SEEM TO HOLD BACK ON THE INSTABILITY. IF ONE WERE TO TWEAK THE
DEWPOINT AT BHM AT 21Z MONDAY FROM 58F (AS FORECAST) TO 62F (WHICH
IS CERTAINLY POSSIBLE)...THEN THE SBCAPE JUMPS FROM LESS THAN 700
TO MORE THAN 1600. I`M NOT ALL THAT COMFORTABLE IN ASSUMING THAT
DEWPOINTS WILL ONLY MAKE IT INTO THE 50S...AND EQUALLY UNEASY
ABOUT HOW MUCH TEMPS FALL AFTER SUNSET MONDAY (GIVEN THE STRENGTH
OF THE LOW LEVEL WINDS). NOT TO MENTION THAT IT IS MARCH...AND
CLIMATOLOGICALLY THIS BEGINS THE HEART OF OUR SEVERE WEATHER
SEASON.

SO...WE ARE EXPECTING A SEVERE STORM THREAT THAT COULD BEGIN AS
EARLY AS 8 PM MONDAY NIGHT (IN THE WEST)...AND COULD LAST AS LATE AS
8 AM TUESDAY MORNING (IN THE EAST). BUT THE PRIMARY THREAT TIME
(BASED ON CURRENT MODEL SOLUTIONS) IS PROBABLY CLOSER TO 10 PM TO 6
AM. ALL SEVERE WEATHER THREATS ARE IN PLAY...INCLUDING TORNADIC
SUPERCELLS JUST AHEAD OR ALONG THE EXPECTED QLCS.