Wednesday, April 28, 2010

April 24, 2010 Alabama Tornadoes

Storm surveys have been conducted this week in Alabama by the National Weather Service Offices in Huntsville and Birmingham in the wake of a series of significant tornadoes that raked north and central parts of the state Saturday night. Surveys were conducted Sunday, but due to the extensive nature of the damage, additional surveys have been conducted as the week has progressed. As of now, the following tornadoes have been confirmed:

From the NWS Huntsville:

1. Cullman County Tornado - EF2 - 115 mph - 6 mile long path - 300 yards wide - 7:13 p.m. Tornado touched down on US 31 and County Road 301 just south of Cullman and moved through the Phelan and Welti communities. Roofs of two businesses were destroyed. Numerous trees and power lines were blown down. Tin roofs from chicken houses were thrown over a mile. No injuries were reported. Approximately 6:51 p.m.

Storm survey by the NWS Huntsville, including radar images and damage photos.

Radar image as the storm approached Dodge City posted by Bill Murray at Alabamawx.com.

Blog post
by Dale Bader of WAAY 31.

Cullman Times article.

Cullman Times article. Note the comments about siren failure.

CBS 42 article and video.

WHNT 19 article.

2. Albertville - Gelraldine - Marshall/Dekalb counties - EF3 - 140 mph - 18.5 mile long path - 3/4 mile wide. In excess of 33 people were injured. Numerous buildings were damaged in Albertville, including the high school, large retail buildings, First Baptist Church, and numerous residences. Approximately 10:14 p.m.

NWS Huntsville storm survey including damage photos and radar images.

Blog post by Dan Satterfield of WHNT 19.

"Albertville Was Luckier Than Most" By Dan Satterfield of WHNT 19.

Radar image as the tornado was over Geraldine, posted by Bill Murray of Alabamawx.com.

Radar image after the storm passed Geraldine posted by Bill Murray at Alabamawx.com.

Video of damage at Albertville.

Damage pictures by Michelle Miklik on Alabamawx.com.

Scottsboro Daily Sentinal article.

Gadsden Times article.

Another Gadsden Times article.

WAAY 31 article, video.

Huntsville Times article.

Photos from the Huntsville Times.

3. Mentone - Dekalb County - EF3 - 140 mph - 2.0 mile long path - 1/4 mile wide. Several mobile homes were completely destroyed southeast of Mentone. Several injuries were reported but no exact number has been determined as of this time. Approximately 11:15 p.m.

Survey by NWS Huntsville, including damage pictures and radar images.

Damage pictures from Alabamawx.com.

4. Mount Vernon (near Collinsville) - Dekalb County - EF4 - 170 mph - 7.3 mile long path, 1/4 to 1/2 mile wide. This storm impacted the Mount Vernon and Dog Town communities in extreme SE Dekalb. The McNutt Memorial United Methodist Church and a house next to it were completely destroyed. There was structural damage to residences along County Rd. 79 and mobile homes on County Rd. 60 were destroyed. Several injuries were reported but an exact number is unknown at this time. Approxinately 11:48 p.m.

NWS Huntsville storm survey, including radar images and damage pictures.

Pictures by Robyn Henry of the damage at Mount Vernon.

Radar image at the time of the warning, posted by Bill Murray on Alabamawx.com.

Mount Vernon damage pictures from Alabamawx.com.

From the NWS Birmingham:

5. Walker/Jefferson/Blount Counties - EF3 - 140 mph - 29.5 mile long path, 400 yards wide - 10:04 p.m. - 10:55 p.m. 70-80 homes and businesses were damaged and one was destroyed. No people were injured or killed as a result of the storm, but a 50 year old woman died on her way to a storm shelter when she slipped and fell.

Video
of lightning associated with the tornadic storm.

Damage Photos
from Cordova by Sandra Short.

Radar image I saved as tornado was near Sumiton.

Radar image as the tornado was near Cordova posted by Bill Murray on Alabamawx.com.

Radar image as the tornado was over Sumiton posted by Bill Murray on Alabamawx.com.

Radar image of the storm as it crossed I-65 posted by Bill Murray on Alabamawx.com.

6. Marion County - EF0 - 80 mph, 7.22 mile long path - 200 yards wide - 4:27-4:38 p.m. Three homes, a vehicle, and out buildings were damaged. 40-60 hardwood trees were uprooted. Tornado was on the ground from just SE of Gu-Win and travelled NE. There were no injuries or fatalities.

Tuscaloosa News article summarizing the tornadoes in Alabama.

7. Blount/Marshall Counties - EF1 - 100 mph - 2.18 mile long path - 200 yards wide - 9:59-10:09 p.m. A tornado formed 4 miles NE of Brooksville and moved NE. A few homes were damaged and a barn was destroyed. Several hundred trees were snapped and uprooted. There were no injuries or fatalities.

8. Fayette County - EF1 - 100 mph - 6.6 mile long path - 200 yards wide - 8:06-8:17 p.m. A tornado travelled from 2 miles south of the intersection of Highway 43 and County Road 26 to just south of Berry. Four homes received minor damage and several hundred trees were snapped or uprooted.

9. Fayette/Walker Counties - EF1 - 100 mph - 4.6 mile long path - 400 yards wide - 8:21-8:35 p.m. Tornado formed northeast of Berry in southeast Fayette and travelled into Walker, dissipating five miles west of Oakman. A 100 foot radio tower was blown down and several hundred tress were snapped or uprooted.

10. Hale County - EF0 - 80 mph - 5.84 mile long path - 100 yards wide - 11:50 a.m.-12:03 p.m. Tornado formed 5 miles northeast of Greensboro and travelled northeast, dissipating near Hogglesville. Three homes experienced minor damage and one barn was destroyed. 30-40 trees were uprooted.

...

4/24/10 Yazoo, Mississippi EF4


I will add a few links periodically on this tornado in upcoming days. First I want to add a couple of very interesting chase accounts.

Eye of the Storm Blog by Greg Nordstrom

Forecastr Blog by Michael Carter

These are both excellent reads on the evolution of the storm that became the "Yazoo Tornado". They are definitely must reading for anyone interested in meteorology, severe weather, storm spotting, and storm chasing. Very educational.

April 23-24, 2010 Tornado Outbreak - NWS Jackson, Mississippi

Video
of the tornado from tornadovideos.net.

Amazing video of a band on the run getting hit by a tornado. WLBT 3 Jackson.

Another great home video of the Yazoo tornado.

....



...

A Thought on Saturday's Tornado Outbreak

I am super-happy and thank God that despite all of the strong to violent tornadoes (EF3's and even an EF4), that no one died directly because of the weather in Alabama Saturday. This is especially remarkable considering that it was a night time event!

The Storm Prediction Center, The NWS in Huntsville and Birmingham, local media, emergency management, and storm spotters all deserve to be congratulated on jobs well-done.

The real key to it all, though, is the fact that people evidently heeded the warnings and generally did an excellent job of taking safety precautions.

And based on a few stories I have read, I have to give credit to God for some miraculous supernatural protection in some cases. Prayers were answered.

...

Monday, April 26, 2010

Saturday, April 24, 2010

A Day to be Weather-Aware in Alabama



Looking at data from the SREF, or Short Range Ensemble Forecast from the SPC (Storm Prediction Center), it appears that the main window for severe weather in Alabama will be from 10 a.m. through 10 p.m., Saturday April 27, 2010. However, a few storms could be severe before or after that time. Also, there may be a lull in the action some of that time.

Parameters seem to be coming together favorably for the possibility of large tornadoes between 4 p.m. and 7 p.m. in West, North, and Central Alabama.


Having said the above, the best thing to do with this powerful and complex developing weather system is watch the weather closely as it develops throughout the day.

  • All outdoor events should be canceled.
  • All Alabamians should be close to a good source of weather information, including local media and NOAA Weather Radio. Please do not depend on sirens.
  • Every family should have a plan in the event a warning is issued for your area.
  • Every warning should be taken with a heightened level of seriousness.
  • If you see a storm in your area, assume that it could produce a tornado and take cover immediately.
  • Avoid mobile homes and driving cars as much as possible in areas with storms. Most people die in mobile homes and cars during tornadoes.
  • Basements and storm shelters provide the best protection. Otherwise, seek shelter on the lowest level of a building, near the middle, preferably a small room such as a closet, and stay away from windows.
  • Take personal responsibility for the safety of you and your family.
  • Stay calm, but remain alert to weather all day and night.
  • Let's make it a goal that regardless of the weather, residents of Alabama experience no serious injuries or death on Saturday.

...

HIGH RISK - Alabama and Mississippi


SPC Convective Outlook, Day One (Saturday 4/24/10)


Tornado Risk


Hail Risk


Severe Wind Risk
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1257 AM CDT SAT APR 24 2010

VALID 241200Z - 251200Z

...THERE IS A HIGH RISK OF SVR TSTMS PORTIONS SERN AR...NERN
LA...MS...CENTRAL/NRN AL...

...THERE IS A MDT RISK OF SVR TSTMS ELSEWHERE FROM PORTIONS E TX TO
CENTRAL/NRN LA...AL...WRN GA...TN...SRN/CENTRAL KY...EXTREME SERN
MO...CENTRAL/SRN/ERN AR....

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING MDT RISK...FROM
GULF COAST OF SE TX TO FL PANHANDLE...TO PORTIONS WV/OH...TO
PORTIONS LOWER MO VALLEY REGION...TO E TX....

OUTBREAK OF NUMEROUS SVR TSTMS IS EXPECTED TODAY...GREATEST
CONCENTRATION/INTENSITY OF WHICH SHOULD INCLUDE STG-VIOLENT TORNADO
THREAT AFFECTING MID-SOUTH...MS DELTA REGION...AND TN VALLEY.

...SYNOPSIS...
SPLIT-FLOW PATTERN IN MID-UPPER LEVELS FEATURES CYCLONE INITIALLY
LOCATED OVER CENTRAL HIGH PLAINS...FCST TO MOVE EWD ACROSS KS TO WRN
MO BY 25/00Z AND WEAKEN ALONG WITH ITS SFC MANIFESTATION.
MEANWHILE...STG SHORTWAVE TROUGH AND SPEED MAX ALOFT -- WHICH
COMPRISED MOST OF INITIAL UPPER CYCLONE OVER SWRN CONUS DURING
PREVIOUS FEW DAYS -- IS FCST TO EJECT NEWD FROM CENTRAL TX TO ERN
MO/SRN IL AREA BY 25/00Z...TAKING OVER AGAIN AS PRIMARY 500 MB LOW.
BY THAT TIME...CORRESPONDING SFC CYCLONE WILL FORM ALONG OCCLUSION
TRIPLE POINT E OF ORIGINAL...AND CLOSE TO NEWER MID-UPPER CYCLONE
CENTER. THIS PROCESS WILL RESULT IN REINFORCEMENT/ACCELERATION OF
INITIALLY STALLED FRONTAL SEGMENT NOW OVER SWRN/CENTRAL TX NNEWD
OVER ERN OK. FRONT SHOULD MOVE ACROSS MUCH OF LA...WRN MS AND WRN
PORTIONS TN/KY BY 25/00Z...TO FL PANHANDLE...AL...MIDDLE-ERN TN AND
ERN KY BY END OF PERIOD....WHEN MID-UPPER CYCLONE SHOULD BE OVER NRN
PORTIONS IL/INDIANA...AND SRN LM AREA.

...LOWER MS VALLEY...MID-SOUTH AND TN VALLEY REGIONS...
TSTMS SHOULD BE INCREASING IN COVERAGE/INTENSITY AROUND BEGINNING OF
PERIOD OVER E TX...LA AND ARKLATEX REGION. FOREGOING AIR MASS --
ALREADY MOISTENED/DESTABILIZED FAVORABLY BY PRIOR/OVERNIGHT THETAE
ADVECTION...WILL FURTHER DESTABILIZE AMIDST SFC DIABATIC HEATING.
AMOUNT OF HEATING IS SOMEWHAT IN QUESTION BECAUSE OF POTENTIAL FOR
CLOUD/ANVIL DEBRIS SPREADING DOWNSTREAM IN MID-UPPER LEVELS FROM
EARLY CONVECTION...PERHAPS INCLUDING TEMPORAL EXTENSION OF ACTIVITY
NOW OVER S TX. STILL...AWAY FROM EXISTING CONVECTION...EVERY
REASONABLE SCENARIO INDICATES THAT MLCINH GENERALLY WILL WEAKEN WITH
NWD EXTENT FROM GULF COAST...SUPPORTING EARLY AND RAPID DEVELOPMENT
AND INTENSIFICATION OF TSTMS FROM MID-MORNING THROUGH
MID-AFTERNOON...AND SUSTAINED THREAT SHIFTING EWD AND NEWD ACROSS
OUTLOOK AREA INTO EVENING/OVERNIGHT HOURS.

INTENSE VERTICAL WIND PROFILES WILL SPREAD ACROSS BROAD WARM/MOIST
SECTOR TODAY...MUCH OF WHICH ALREADY IS IN PLACE ACROSS MUCH OF
LA...MS AND COASTAL AL. THIS AIR MASS WILL SPREAD INLAND TOWARD TN
VALLEY AS CONVECTION/PRECIP NOW OVER TN/AL/GA SHIFTS NEWD. SFC DEW
POINTS WILL BE 70S INVOF GULF COAST...TRANSITIONING TO UPPER 60S AS
FAR N AS TN AND LOW-MID 60S TO OH VALLEY. WEAKENING LAPSE RATES
ALOFT AND BUOYANCY WITH NWD EXTENT...FROM TN VALLEY TO OH VALLEY AND
GREAT LAKES...RENDER PROGRESSIVELY MORE CONDITIONAL NATURE TO SVR
THREAT...THOUGH KINEMATIC PROFILES WILL BECOME FAVORABLE OVER VERY
LARGE AREA S OF GREAT LAKES BY EVENING/OVERNIGHT HOURS.

MULTIPLE CONVECTIVE EPISODES AND STORM MODES ARE EXPECTED IN THIS
SITUATION...AGGREGATE OF WHICH SHOULD YIELD DENSE CONCENTRATION OF
SVR EVENTS BY END OF PERIOD ACROSS MDT/HIGH CATEGORICAL RISK AREAS.
THOUGH DISCRETE/CYCLIC TORNADIC SUPERCELLS ARE MOST POTENTIALLY
DANGEROUS THREAT...ESPECIALLY OVER HIGH RISK AREA...CLUSTERED AND
QUASI-LINEAR CONVECTIVE ELEMENTS WITH EMBEDDED BOW/LEWP FORMATIONS
AND SUPERCELLS ALSO APPEAR PROBABLE. STRENGTHENING DEEP-LAYER WINDS
AND RELATED FAST STORM MOTIONS PORTEND LONG TRACKS FOR SUPERCELLS
AND FOR SOME OF THEIR TORNADOES...AS WELL AS FOR SWATHS OF DAMAGING
WIND WITH ANY BOW/LEWP FEATURES. THIS SUPPORTS RATHER ROBUST
PROBABILITIES FOR ALL SEVERE MODES.

PARAMETER SPACES IN FCST SOUNDINGS OVER HIGH RISK AREA -- SHIFTING
NEWD FROM LATE MORNING THROUGH AFTERNOON -- INCLUDE 50-60 KT LLJ
SUPPORTING VERY LARGE HODOGRAPHS WITH 0-1 AND 0-1 KM SRH 300-600
J/KG. ALSO EXPECT 50-60 KT EFFECTIVE SHEAR MAGNITUDES BENEATH
110-140 KT 250 MB JET MAX AND 60-90 KT 500 MB WINDS...POTENTIALLY
JUXTAPOSED WITH MLCAPE 1500-2500 J/KG.

SUPERCELL/TORNADO THREAT MAY CARRY INTO EVENING/OVERNIGHT HOURS OVER
CENTRAL/SRN APPALACHIANS REGION AND WRN GA BEFORE DIMINISHING.

...IA...MO VALLEY REGION...
SCATTERED STG-SVR TSTMS ARE EXPECTED TO DEVELOP ACROSS THIS AREA
INVOF LARGE CYCLONE ALOFT...AS STEEP MID-UPPER LEVEL LAPSE RATES
COLLOCATED WITH BROAD AREA OF LOW-LEVEL CONVERGENCE AND
DIABATIC/DIURNAL DESTABILIZATION OF BOUNDARY LAYER. MAIN CONCERN
WILL BE SVR HAIL...THOUGH POTENTIAL FOR DAMAGING GUSTS EXISTS. SVR
POTENTIAL SHOULD WANE SIGNIFICANTLY AFTER SUNSET.

..EDWARDS/GARNER.. 04/24/2010

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
CURRENT UTC TIME: 0614Z (1:14AM), RELOAD THIS PAGE TO UPDATE THE TIME

Friday, April 23, 2010

Special Wx Statement, NWS Huntsville

000
WWUS84 KHUN 231602
SPSHUN

SPECIAL WEATHER STATEMENT...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1102 AM CDT FRI APR 23 2010

ALZ001>010-016-TNZ076-096-097-240300-
LAUDERDALE-COLBERT-FRANKLIN AL-LAWRENCE-LIMESTONE-MADISON-MORGAN-
MARSHALL-JACKSON-DEKALB-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
1102 AM CDT FRI APR 23 2010

...TORNADO OUTBREAK POSSIBLE ON SATURDAY...
...SEVERE WEATHER POSSIBLE AS EARLY AS LATE TONIGHT...

A POTENTIALLY DANGEROUS WEATHER SITUATION MAY DEVELOP ON SATURDAY AS
A POWERFUL WEATHER SYSTEM TRACKS THROUGH THE LOWER MISSISSIPPI AND
TENNESSEE VALLEYS.

AN INITIAL ROUND OF STRONG TO POSSIBLY SEVERE THUNDERSTORMS ARE
EXPECTED EARLY THIS EVENING INTO SATURDAY MORNING AS A WARM FRONT
MOVES ACROSS THE REGION. THESE STORMS MAY PRODUCE HAIL AND LOCALLY
DAMAGING WINDS.

THE GREATEST RISK FOR SEVERE THUNDERSTORMS...INCLUDING
TORNADOES...IS EXPECTED FROM EARLY SATURDAY AFTERNOON THROUGH THE
EVENING HOURS. STORMS THAT DEVELOP AHEAD OF AN APPROACHING
SQUALL LINE SATURDAY AFTERNOON AND EVENING WILL HAVE THE HIGHEST
THREAT OF PRODUCING STRONG AND PERHAPS LONG-LIVED TORNADOES.

A FINAL ROUND OF SEVERE THUNDERSTORMS WILL OCCUR WITH A SQUALL LINE
SATURDAY NIGHT...WHICH WILL BE CAPABLE OF PRODUCING DAMAGING WINDS
AND ISOLATED TORNADOES.

RESIDENTS OF THE TENNESSEE VALLEY ARE URGED TO REVIEW THEIR TORNADO
SAFETY PLAN NOW...AND HAVE A WAY TO RECEIVE SEVERE WEATHER
INFORMATION. IT IS ALSO A GOOD IDEA TO MAKE SURE YOUR NOAA ALL
HAZARDS WEATHER RADIO HAS FRESH BATTERY POWER.

$$

KULA




Birmingham/Huntsville Morning AFD's

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
658 AM CDT FRI APR 23 2010

...DANGEROUS SEVERE WEATHER OUTBREAK EXPECTED ON SATURDAY...

.DISCUSSION...

LARGE SCALE UPPER AND SURFACE LOW CURRENTLY MOVING THROUGH THE
CENTRAL PLAINS IS ALREADY CAUSING HAVOC ACROSS MUCH OF THE
NATION'S HEARTLAND...AND AS IT TRANSITIONS INTO THE MS VALLEY MORE
DANGEROUS WEATHER IS EXPECTED LATER TODAY. THIS WILL BE THE FIRST
OF A SIGNIFICANT ONE-TWO PUNCH THAT IS EXPECTED ACROSS CENTRAL
ALABAMA OVER THE NEXT TWO DAYS.

MY FIRST CONCERN IS LATER TONIGHT AS THE LEFTOVERS APPROACH OUR
WESTERN COUNTIES...PROBABLY NEAR SUNSET. TONIGHT'S FORECAST
REMAINS CONFUSING...TO SAY THE LEAST...AS THERE IS A LOT OF
UNCERTAINTY TO WHETHER UPSTREAM CONVECTION WILL AFFECT THE WESTERN
HALF OF THE CWA. TO MAKE IT EVEN MORE COMPLEX...THE NUMBER TWO PUNCH
WILL BE GETTING ITSELF RAMPED UP SHORTLY AFTER MIDNIGHT AS A
DECENT WARM FRONT WILL BEGIN SETTING UP ACROSS AREAS OF CENTRAL
MS...EASTWARD INTO WESTERN AND CENTRAL ALABAMA. ALTHOUGH THE
INITIAL THREAT THIS EVENING AND TONIGHT LOOKS TO BE RATHER
MINIMAL...A FEW SURFACE BASED STORMS ARE POSSIBLE AS THEY ROLL
THROUGH CENTRAL AND SOUTHERN MS LATER TODAY...AND WILL BE ON OUR
DOORSTEP...LIKELY AFTER 6 PM OR SO. THEN LATER AS THE WARM FRONTAL
BOUNDARY BEGINS TO GET ESTABLISHED AFTER MIDNIGHT...ELEVATED
STORMS COULD THREATEN A GOOD PORTION OF THE WEST-CENTRAL AREA WITH
HAIL AND SOME DAMAGING WINDS. IT IS ALSO POSSIBLE...BUT NOT LIKELY
THAT A FEW OF THESE STORMS COULD GET SURFACE ROOTED...BUT WILL
REALLY HAVE TO WATCH THE MESOSCALE CLOSELY AS THIS PRELIMINARY
EVENT BEGINS TO UNFOLD.

THIS LEADS RIGHT INTO PUNCH NUMBER TWO...WHICH IS SLATED FOR MUCH
OF THE DAY SATURDAY AS A SHORTWAVE VORT MAX ROLLS AROUND THE
SOUTHERN EDGE OF THE MAIN UPPER LOW. THIS WILL CREATE A MORE THAN
IMPRESSIVE SURFACE LOW JUST TO OUR WEST THAT WILL MOVE AND DEEPEN
RAPIDLY ACROSS THE MID MS VALLEY AND EVENTUAL OHIO VALLEY. THIS
WILL CREATE AN ENVIRONMENT ACROSS CENTRAL ALABAMA THAT WILL BE
NOTHING SHORT OF A CLASSIC SEVERE WEATHER OUTBREAK. EXPECT OUR
OLD WARM FRONT TO LIFT RAPIDLY NORTHWARD THROUGH THE MORNING HOURS
ON SATURDAY...LEAVING THE AREA IN A HIGHLY UNSTABLE AND FAVORABLY
SHEARED AIRMASS FOR MUCH OF SATURDAY AFTERNOON....EVENING...AND AT
LEAST THE FIRST HALF OF THE OVERNIGHT HOURS. WHILE THE INSTABILITY
PARAMETERS REMAIN SOMEWHAT MARGINAL...BUT SIGNIFICANT ENOUGH TO
SUPPORT LONG-LIVED SUPERCELLS...THE BACKING SURFACE WINDS AND MID
AND UPPER JET WILL CERTAINLY BE CONDUCIVE FOR TORNADOES...SOME OF
WHICH WILL BE STRONG AND LONG-LIVED. NOT TO MENTION THE THREAT OF
HEAVY RAIN...LARGE HAIL...AND DAMAGING SURFACE WINDS WHICH WILL
ACCOMPANY THESE CELLS. THE DANGER WILL CONTINUE INTO THE EVENING
HOURS AS THE STEEP UPPER LAPSE RATES AND SOME MID LEVEL DRY AIR WILL
KEEP THE THREAT GOING UNTIL IT EXITS NORTH AND EAST THROUGH THE
OVERNIGHT HOURS.

THIS IS A HIGHLY DANGEROUS SITUATION THAT LOOMS FOR
SATURDAY...WHERE THE GREATEST THREAT WILL LIKELY REMAIN FROM AROUND
NOON UNTIL MIDNIGHT. PLEASE MAKE PREPARATIONS AND PLANS NOW IN THE
EVENT THAT SEVERE WEATHER WILL AFFECT YOU AT SOME POINT ON
SATURDAY. TAKE ALL NECESSARY PRECAUTIONS TO PROTECT YOUR LIFE AND
PROPERTY!

17/KLAWS

-----

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
652 AM CDT FRI APR 23 2010


.DISCUSSION... /ISSUED 437 AM CDT FRI APR 23 2010/

..SEVERE WEATHER OUTBREAK EXPECTED ACROSS THE TENNESSEE VALLEY...

LATEST WATER VAPOR IMAGERY AND H5 RUC ANALYSIS CONTINUE TO SHOW
AGGRESSIVE UPPER LEVEL CYCLONE OVER THE FOUR CORNERS REGION...WITH
BOTH THE MID AND UPPER LEVEL SPEED MAX ROUNDING THE BASE OF THE
TROUGH ATTM. AT THE SURFACE...A SQUALL LINE STRETCHES SOUTH INTO
TEXAS FROM THE CENTER OF THE LOW IN EAST COLORADO...WITH A WARM
FRONT EXTENDING INTO WEST TENNESSEE. CLOSER TO HOME...WINDS ARE
GENERALLY LIGHT AND SOUTHERLY WITH A FEW CLOUDS BRUSHING OVER THE
AREA. DEWPOINTS HAVE STEADILY BEEN CLIMBING...AND ARE NOW IN THE LOW
50S.

ATTENTION FOR THE FORECAST CONTINUES TO FOCUS UPON THE CYCLONE TO
THE WEST...AS THIS SYSTEM WILL BRING MULTIPLE ROUNDS OF SEVERE
WEATHER TO THE GREATER SOUTHEAST TODAY AND SATURDAY.

MUCH OF TODAY WILL BE QUIET AS WEAK UPPER LEVEL RIDGING REMAINS IN
PLACE THROUGH MIDDAY. HOWEVER AS TEMPERATURES CLIMB THIS AFTERNOON
INTO THE 80S /AND DEWPOINTS INCREASE INTO THE UPPER 50S/...SURFACE
BASED ISOLATED CONVECTION WILL DEVELOP THIS AFTERNOON IN THE WEST.
THESE STORMS WILL BE CAPABLE OF GUSTY WINDS...HAIL...AND LOCALLY
HEAVY RAINFALL. WHILE THE GFS SUGGESTS WE WILL REMAIN CAPPED THROUGH
THE AFTERNOON...DO NOT BUY INTO THAT SOLUTION ATTM GIVEN THE
EXPECTED DEGREE OF WARMING AT THE SURFACE.

HOWEVER THIS EVENING AS INSOLATION WANES AND WE DECOUPLE...ANY
LINGERING EVENING STORMS SHOULD BECOME MORE ELEVATED IN NATURE.
ADDITIONAL THUNDERSTORMS /ASSOCIATED WITH THE CURRENT SURFACE LOW/
SHOULD BREAK OUT ACROSS THE AREA...AND THESE WILL NEED TO BE
MONITORED FOR THEIR SEVERE POTENTIAL OF PRODUCING DAMAGING WINDS AND
HAIL. MEANWHILE TO OUR SOUTH...A SECONDARY SURFACE LOW WILL FORM
OVER SE TEXAS...AND RAPIDLY SHIFT TOWARD NORTHERN LOUISIANA BY 12Z
SATURDAY. LOCALLY RUN WRF INDICATES A BREAK IN THE THUNDERSTORMS
SATURDAY MORNING /AROUND 15Z/ FOR A FEW HOURS AS THIS SECOND SURFACE
LOW RAPIDLY SHIFTS TOWARD THE NORTHEAST.

MUCH OF THE SATURDAY FORECAST HINGES ON CONDITIONS EARLY SATURDAY
MORNING. FOR EXAMPLE...FRIDAY NIGHT THUNDERSTORMS MAY WORK OVER THE
ATMOSPHERE AND PRECLUDE CONVECTION INITIATION OVER THE CWFA UNTIL AT
LEAST MIDDAY SATURDAY. ON A CONTRARY...IF THERE ARE ANY BREAKS IN
THE CLOUDS ON SATURDAY MORNING...INSOLATION WILL RAPIDLY DESTABILIZE
THE ATMOSPHERE. FOR NOW...WILL HEDGE THE FORECAST TOWARD THE LOCALLY
RUN WRF...WHICH INITIALIZES DISCREET SUPERCELLS SOUTHWEST OF THE CWFA
SATURDAY MORNING...AND TRACK THEM ACROSS THE MS/AL BORDER AROUND
19Z SATURDAY. WHILE THIS HAS BEEN MENTIONED FOR SEVERAL FORECAST
DISCUSSIONS NOW IT BEARS REPEATING: ANY STORMS THAT DEVELOP ON
SATURDAY WILL BE CAPABLE OF PRODUCING TORNADOES...LARGE
HAIL...DAMAGING WINDS AND LOCALLY HEAVY RAINFALL. HODOGRAPHS AND LOW
LEVEL HELICITY CONTINUE TO BE IMPRESSIVE /WITH 0-3 SRH AROUND 7-800
M2/S2/ INDICATIVE OF THE VERY HIGH MID AND LOW LEVEL BULK SHEAR
VALUES PRESENT ACROSS THE AREA. THE LATEST OUTLOOK FROM THE STORM
PREDICTION CENTER /SPC/ PLACES THE TENNESSEE VALLEY IN A MODERATE
RISK FOR THE DAY...AND HIGHLIGHTS THE POTENTIALLY SERIOUS NATURE OF
THIS EVENT.

TOWARD DUSK ON SATURDAY...EXPECT A TRANSITION TOWARD A MORE LINEAR
TYPE OF STORM SYSTEM AHEAD OF THE MAIN COLD FRONT. LOCALLY RUN WRF
SUGGESTS THIS LINE WILL FORM IN THE WEST AROUND 00Z SUNDAY...AND
PUSH THROUGH THE CWFA DURING THE EVENING HOURS...EXITING NORTHEAST
ALABAMA AROUND MIDNIGHT. NAM INDICATES AN INSTABILITY AXIS
RESURGENCE ALONG THE LINE AND SHEAR SHOULD BECOME MORE
UNIDIRECTIONAL...INDICATING MOSTLY A DAMAGING WIND THREAT /ALONG
WITH THE CONTINUED THREAT OF TORNADOES WITHIN ANY LINE BREAK/.

STARTING TONIGHT THROUGH SATURDAY NIGHT...LOCALLY HEAVY RAINFALL IS
POSSIBLE GIVEN THE MOIST ENVIRONMENT /AS INDICATED BY THETAE AXIS
AND PWATS AOA 1.50IN/ AND THE MULTIPLE ROUNDS OF THUNDERSTORMS.
STORM TOTAL PRECIPITATION COULD BE AS HIGH AS 2 OR 3 INCHES IN SOME
LOCATIONS. AS AN ADDITIONAL HAZARD...GRADIENT WINDS ON SATURDAY WILL
BE VERY GUSTY GIVEN THE STRONG LOW LEVEL JET /35-45KT AT 2K
FT/...AND A WIND ADVISORY MAY BE NEEDED FOR PORTIONS OF THE AREA.

IF YOU HAVE NOT ALREADY DONE SO...TAKE THE TIME TODAY TO PREPARE FOR
SEVERE WEATHER...THIS INCLUDES KNOWING WHERE YOU WILL GO IN THE
EVENT A TORNADO WARNING IS ISSUED FOR YOUR AREA. OUR OFFICE WILL
CONTINUE TO HIGHLIGHT THIS SEVERE WEATHER THREAT IN OUR SPECIAL
WEATHER STATEMENT /SPS/ AND OUR HAZARDOUS WEATHER OUTLOOK
/HWO/...AND STAY IN CONSTANT CONTACT WITH OUR LOCAL PARTNERS AS WE
GEAR UP FOR THIS WEEKEND EVENT.

THE FORECAST PAST SUNDAY REMAINS LARGELY UNCHANGED...AS UNRULY
NORTHWEST FLOW ON THE BACKSIDE OF THE DEPARTING UPPER TROUGH SENDS
MULTIPLE SHORTWAVES ACROSS THE AREA. THE CHANCE FOR LIGHT RAIN
SHOWERS WILL PERSIST THROUGH TUESDAY ACROSS THE AREA BEFORE SURFACE
HIGH PRESSURE BUILDS INTO THE AREA ON WEDNESDAY. AS THE LOW LEVEL
FLOW BECOMES SOUTHERLY BY THURSDAY AND FRIDAY...TEMPERATURES AND
DEWPOINTS WILL WARM AHEAD OF A SYSTEM APPROACHING FROM THE WEST.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&

$$

DISCUSSION...JLL

Moderate Risk in Alabama Saturday




DAY 2 CONVECTIVE OUTLOOK    
NWS STORM PREDICTION CENTER NORMAN OK
1235 AM CDT FRI APR 23 2010

VALID 241200Z - 251200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF SWRN AND S-CNTRL
KY...WRN AND MIDDLE TN...ERN AR...NWRN LA...MUCH OF MS...WRN AND NRN
AL AND FAR NWRN GA...

...THERE IS A SLGT RISK OF SVR TSTMS FROM LOWER ELEVATIONS OF THE
CNTRL AND SRN PLAINS EWD TO THE CNTRL/SRN APPALACHIANS AND ERN GULF
STATES...

..SYNOPSIS


A DYNAMIC LARGE-SCALE PATTERN WILL CONTINUE THROUGH THE DAY TWO
PERIOD FEATURING A DEEP-LAYER CYCLONE WHICH WILL TRACK FROM THE
CNTRL PLAINS ENEWD THROUGH THE MID MS VALLEY BEFORE RE-DEVELOPING
INTO IL/IND BY SUNDAY MORNING. OF POTENTIALLY MORE SIGNIFICANCE IS
A VIGOROUS VORTICITY MAXIMUM AND ATTENDANT 80+ KT MIDLEVEL JET
STREAK WHICH ARE FORECAST TO ROUND THE LARGE-SCALE TROUGH BASE OVER
TX PRIOR TO ACCELERATING NEWD --AS A NEGATIVELY-TILTED WAVE--
THROUGH THE ARKLATEX/LOWER MS VALLEY AND EVENTUALLY INTO THE OH
VALLEY.

AT THE SURFACE...A CYCLONE ASSOCIATED WITH THE PRIMARY UPPER-LEVEL
LOW WILL DEVELOP SLOWLY EWD FROM THE MID MO VALLEY PRIOR TO
WEAKENING OVER IA. AN ASSOCIATED COLD FRONT WILL PUSH SEWD THROUGH
THE MID MO VALLEY AND CNTRL PLAINS...EVENTUALLY INTO THE MID MS
VALLEY. MEANWHILE...A SECONDARY CYCLOGENETIC LOW WILL DEVELOP
RAPIDLY NEWD FROM THE VICINITY OF THE ARKLATEX TO NEAR PAH BY MID
AFTERNOON AND INTO NRN IND BY THE END OF THE PERIOD. A COLD OR
PACIFIC FRONT ASSOCIATED WITH THIS LOW WILL SWEEP EWD THROUGH THE
MID/LOWER MS VALLEYS AND MUCH OF THE OH VALLEY SATURDAY INTO
SATURDAY NIGHT.

--TORNADO OUTBREAK POSSIBLE OVER PARTS OF THE LOWER MS AND TN
VALLEYS INTO CNTRL GULF STATES SATURDAY INTO SATURDAY NIGHT--

...THE LOWER OH/LOWER MS VALLEYS EWD INTO THE CNTRL/SRN APPALACHIANS
INTO THE ERN GULF STATES...

THE PRESENCE OF A BROAD...MOIST WARM SECTOR /I.E. BOUNDARY LAYER DEW
POINTS RANGING FROM AROUND 60 F NEAR THE OH RIVER...TO UPPER 60S TO
AROUND 70 F OVER THE LOWER MS VALLEY AND CNTRL GULF STATES/ WILL SET
THE STAGE FOR A SIGNIFICANT...AND WIDESPREAD OUTBREAK OF SEVERE
THUNDERSTORMS THROUGH MUCH OF THE DAY TWO PERIOD. THIS MOISTURE IN
CONJUNCTION WITH RELATIVELY STEEP MIDLEVEL LAPSE RATES AND DAYTIME
HEATING WILL CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS BY
AFTERNOON OVER THE LOWER MS VALLEY WHERE MLCAPE WILL APPROACH
1500-2000 J/KG. WHILE CONVECTIVE INSTABILITY WILL LIKELY DECREASE
WITH NWD EXTENT OWING TO MORE WIDESPREAD CLOUDS AND PERSISTENT
CONVECTIVE PRECIPITATION...IT WILL STILL BE SUFFICIENT TO SUPPORT
SEVERE STORMS.

CLUSTERS OF SEVERE TSTMS ARE FORECAST TO BE ONGOING SATURDAY MORNING
FROM THE VICINITY OF THE COLD FRONT OVER ERN TX EWD INTO THE LOWER
MS VALLEY. ACTIVITY WILL SPREAD NWD/NEWD THROUGH THE PERIOD IN
ADVANCE OF THE NEGATIVELY-TILTED MIDLEVEL TROUGH RAPIDLY LIFTING
NEWD THROUGH THE LOWER/MID MS VALLEYS. THE COMBINATION OF A 60-90
KT MIDLEVEL WIND FIELD AND A DEVELOPING 50-60 KT LLJ WILL RESULT IN
STRONG VERTICAL SHEAR ACROSS THE WARM SECTOR. THIS SUGGESTS A HIGH
LIKELIHOOD OF MULTIPLE BANDS/CLUSTERS OF SUPERCELLS CAPABLE OF
DAMAGING WINDS...LARGE HAIL AND TORNADOES PERSISTING THROUGH THE
PERIOD.

THE GREATEST THREAT FOR CYCLIC SUPERCELLS CAPABLE OF SIGNIFICANT
TORNADOES WILL EXIST FROM THE VICINITY OF THE SECONDARY LOW TRACK
SEWD INTO THE WARM SECTOR /I.E. LARGELY DELINEATED BY MDT RISK
AREA/. HERE...ENVIRONMENT WILL BE CHARACTERIZED BY DEEP EFFECTIVE
INFLOW LAYERS YIELDING EFFECTIVE SRH IN EXCESS OF 200-300+
M2/S2...MODERATE INSTABILITY AND 50-70 KT OF DEEP-LAYER SHEAR.
SEVERE STORMS CAPABLE OF MAINLY DAMAGING WINDS AND TORNADOES WILL
CONTINUE THROUGH THE NIGHT WITH THE THREAT EXTENDING NWD THROUGH THE
OH RIVER AND AS FAR E AS THE CNTRL/SRN APPALACHIANS AND ERN GULF
STATES.

..MID/LOWER MO VALLEYS INTO THE MID MS VALLEY


A SECONDARY CONCENTRATION OF STRONG TO SEVERE STORMS IS EXPECTED TO
DEVELOP DURING THE AFTERNOON ALONG AND AHEAD OF THE SECONDARY COLD
FRONT AND INVOF THE DEEP-LAYER CYCLONE SLOWLY SHIFTING ENEWD. HERE
RESIDUAL BOUNDARY LAYER DEW POINTS IN THE MID 40S TO MID 50S COUPLED
WITH DAYTIME HEATING AND COLD MIDLEVEL TEMPERATURES /I.E. -20 C AT
500 MB/ WILL YIELD POCKETS OF MODERATE INSTABILITY WHERE MLCAPE WILL
APPROACH 1000-1500 J/KG.

REGION WILL RESIDE ON THE INNER ENVELOPE OF STRONGER DEEP-LAYER
SHEAR ASSOCIATED WITH THE SYNOPTIC SYSTEM. AS SUCH...SETUP WILL BE
FAVORABLE FOR ORGANIZED MULTICELL OR SUPERCELL STRUCTURES CAPABLE OF
MAINLY SEVERE HAIL. ISOLATED TORNADOES WILL ALSO BE POSSIBLE NEAR
THE SURFACE LOW WHERE AMBIENT...VERTICAL VORTICITY WILL BE
MAXIMIZED.

..MEAD.. 04/23/2010

Thursday, April 22, 2010

Moderate Risk Tomorrow


Day Two (Friday) Probablities, from SPC


Day Two (Friday) Outlook, from SPC

DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK
1228 PM CDT THU APR 22 2010

VALID 231200Z - 241200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF AR AND NRN LA...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE LOWER MS VALLEY...SRN PLAINS...OZARKS...MID MO VALLEY AND SRN PLAINS...

...A SIGNIFICANT SEVERE WEATHER EVENT POSSIBLE LATE FRIDAY AFTERNOON INTO FRIDAY EVENING ACROSS PARTS OF AR AND NRN LA......THE START OF A TORNADO OUTBREAK POSSIBLE LATE FRIDAY NIGHT INTO SATURDAY MORNING POSSIBLE ACROSS THE ARKLATEX AND LOWER MS VALLEY...

...LOWER TO MID MS VALLEY...A WELL-DEVELOPED SYSTEM OVER THE CNTRL ROCKIES WILL MOVE INTO THE SRN PLAINS FRIDAY. AN IMPRESSIVE 80 TO 90 KT MID-LEVEL JET WILL ROUND THE BASE OF THE UPPER-LEVEL TROUGH MOVING QUICKLY NEWD INTO THE SRN PLAINS FRIDAY AFTERNOON. AS LARGE-SCALE ASCENT INCREASES ACROSS THE ARKLATEX...A LOW-LEVEL JET IS FORECAST TO STRENGTHEN AND MOVE NWD ACROSS LA INTO SRN AR. CONVECTION ASSOCIATED WITH THE LOW-LEVEL JET SHOULD INITIATE ACROSS NRN LA AND SRN AR FRIDAY AFTERNOON WITH THE STORMS EXPANDING QUICKLY IN COVERAGE ACROSS ERN AR...NRN MS AND SRN MO. FORECAST SOUNDINGS FRIDAY AFTERNOON IN NRN LA AND SRN AR SHOW MODERATE INSTABILITY...STRONG DEEP LAYER SHEAR WITH 0-1 KM SHEAR AROUND 30 KT. THIS ENVIRONMENT SHOULD BE FAVORABLE FOR SUPERCELLS WITH A POTENTIAL FOR TORNADOES ESPECIALLY IF THE DEVELOPING STORMS BECOME SFC-BASED BY LATE FRIDAY AFTERNOON. AN ISOLATED STRONG TORNADO ALONG WITH A SUBSTANTIAL WIND DAMAGE THREAT WILL BE POSSIBLE AS STORMS MOVE QUICKLY NEWD OUT OF NRN LA ACROSS ERN AR AND WRN MS FRIDAY EVENING.

DURING THE OVERNIGHT PERIOD...THE UPPER-LEVEL SYSTEM ACROSS THE GREAT PLAINS IS FORECAST TO BECOME INCREASINGLY ORGANIZED. MODEL FORECASTS DEVELOP A PRONOUNCED LOW-LEVEL JET ACROSS THE NW GULF OFMEXICO FRIDAY NIGHT...MOVING THIS FEATURE QUICKLY NNEWD ACROSS LA AROUND DAYBREAK SATURDAY. THUNDERSTORMS ARE FORECAST TO INITIATE ALONG THE WRN EDGE OF THE LOW-LEVEL JET ACROSS EAST TX AFTER MIDNIGHT WITH THIS CONVECTION SPREADING NEWD ACROSS THE ARKLATEX LATE FRIDAY NIGHT INTO SATURDAY MORNING. INCREASING LARGE-SCALE ASCENT ASSOCIATED WITH THE EXIT REGION OF AN APPROACHING MID-LEVELJET...STRONG VERTICAL SHEAR AND MODERATE INSTABILITY SHOULD MAKE CONDITIONS VERY FAVORABLE FOR SUPERCELLS ACROSS THE ARKLATEX LATE IN THE PERIOD. FORECAST SOUNDINGS ACROSS NRN LA AND SRN AR FROM 09Z TO12Z SATURDAY SUGGEST LOW-LEVEL SHEAR WILL RAPIDLY BECOME FAVORABLE FOR TORNADOES. THE SYNOPTIC SETUP ALONG WITH OUTPUT FROM VARIOUS SEVERE PARAMETERS SUGGEST THAT A TORNADO OUTBREAK MAY START LATE FRIDAY NIGHT ACROSS NRN LA...SRN AR...WRN MS AND POSSIBLY FAR NE TX. TORNADOES WILL BE POSSIBLE WITH THE MORE DOMINANT DISCRETE SUPERCELLS WITH A FEW STRONG TORNADOES POSSIBLE. IN ADDITION...LARGE HAIL AND WIND DAMAGE APPEARS LIKELY WITH SUPERCELLS THAT DEVELOP FRIDAY NIGHT.

THE MAIN UNCERTAINTY CONCERNING THE OUTBREAK POTENTIAL IS TIMING WITH THE LOW-LEVEL JET LATE IN THE PERIOD. AT THIS POINT...MODEL FORECASTS FOCUS THE LOW-LEVEL JET ACROSS THE ARKLATEX AND LOWER MS VALLEY JUST BEYOND 12Z ON SATURDAY SUGGESTING THE POTENTIAL FOR A TORNADO OUTBREAK COULD HOLD OFF UNTIL AFTER 12Z SATURDAY.

...MID-MO VALLEY...AN UPPER-LEVEL LOW IS FORECAST TO MOVE INTO THE CNTRL PLAINS FRIDAY AS A CORRIDOR OF LOW-LEVEL MOISTURE SETS UP FROM ERN KS NWWD ACROSS SRN NEB WHERE SFC DEWPOINTS SHOULD BE IN THE MID 50S TO LOWER 60S F. MODEL FORECASTS DEVELOP MODERATE INSTABILITY FROM CNTRL NEB SEWD ACROSS ERN KS AND WRN MO. THUNDERSTORMS APPEAR LIKELY TO INITIATE ALONG THE INSTABILITY AXIS LATE FRIDAY AFTERNOON WHERE FORECASTS SOUNDINGS SHOW STEEP MID-LEVEL LAPSE RATES AND MODERATE TO STRONG VERTICAL SHEAR SUGGESTING SUPERCELLS WITH LARGE HAIL WILL BE POSSIBLE. VERY LARGE HAIL MAY OCCUR WITH THE MORE DOMINANT SUPERCELLS ACROSS ERN NEB...FAR NE KS AND NW MO AS THE EXIT REGION OF A MID-LEVEL JET MOVES INTO THE REGION FROM THE SOUTH. THIS COMBINED WITH MLCAPE VALUES AROUND 2000 J/KG AND 850 TO 500 MB LAPSE RATES BETWEEN 7.0 AND 7.5 C/KM MAY BE SUFFICIENT FOR VERY LARGE HAIL. THIS THREAT FOR 2 INCH AND GREATER SIZE HAIL SHOULD BE FOCUSED WITH THE MORE DOMINANT SUPERCELLS ACROSS ERN NEB...FAR NE KS AND NW MO AS THE EXIT REGION OF A MID-LEVEL JET MOVES INTO THE REGION FROMTHE SOUTH LATE FRIDAY AFTERNOON.

..BROYLES.. 04/22/2010

Upcoming Severe Weather Threat


Significant Tornado Parameter >=5, Saturday at 7 p.m.

Excerpts from National Weather Service Area Forecast Discussions this morning:

HUNTSVILLE

THE ATMOSPHERE WILL DESTABILIZE RAPIDLY ON SATURDAY AS A STRONG LLJ /50-60KT/ BARES DOWN ON THE VALLEY...AND SUPERCELLS WILL DEVELOP THROUGH THE AFTERNOON HOURS. BULK SHEAR...LOW LEVEL HELICITY...AND INSTABILITY SUGGEST TORNADOES...DAMAGING WINDS...AND LARGE HAIL WILL BE POSSIBLE FROM THESE STORMS ON SATURDAY /ESPECIALLY IN THE WESTERN TWO-THIRDS OF THE CWFA

BIRMINGHAM, AL

BUT ALL SEVERE THREATS APPEAR TO BE IN THE CARDS. WHILE MOST OF THE UPPER PROFILES REMAIN SATURATED...IT DOES LOOK LIKE THE UPPER LAPSE RATES ARE STEEP ENOUGH TO CONTINUE TO INCLUDE A DAMAGING WIND AND LARGE HAIL THREAT FOR THE MORE ROBUST CELLS. MEANWHILE...THE LOWER LEVEL TURNING AND STRENGTHENING WIND FIELDS WILL BE SUPPORTIVE OF TORNADOES...INCLUDING THE THREAT FOR SOME STRONG AND LONG-LIVED TORNADOES. WE WILL NEED TO FOCUS THE ATTENTION EARLY JUST UPSTREAM FOR CELLS THAT FORM IN CENTRAL MS AND MOVE INTO WESTERN SECTIONS OF THE CWA...HOWEVER... IT IS STARTING TO LOOK MORE AND MORE LIKE WE WILL HAVE OUT OWN CELL DEVELOPMENT BY THE MIDDLE AFTERNOON AND EVENING HOURS.

JACKSON, MS

NUMEROUS SVR STORMS ARE EXPECTED TO BREAK OUT BETWEEN 5AM AND MID/LATE MORNING. IT APPEARS THE GREATEST RISK FOR SAT WILL BE FROM 5 AM TO 2PM. MULTIPLE SUPERCELLS ARE EXPECTED WITH A COUPLE CLUSTERS OF STORMS DEVELOPING. INSTABILITY WILL BE SOLID WITH MLCAPE IN THE 1500 J/KG RANGE. LOW LEVEL SHEAR WILL BE STRONG TO THE NOCTURNAL LL JET AND JUST THE PLAIN RESPONSE TO THE INTENSE SYSTEM APPROACHING. CONDITIONS WILL EXIST FOR A SIGNIFICANT SEVERE EVENT. IT APPEARS THAT THE STRONGEST TORNADO INGREDIENTS AND MOST FAVORABLE TIME FOR TORNADOES WILL BE BETWEEN 5-11AM. SUCH PARAMETERS WILL SUPPORT THE CHANCE FOR A FEW STRONG TORNADOES. IN ADDITION...QUARTER TO GOLF BALL WILL BE POSSIBLE WITH ANY STORM ALONG WITH DM WINDS. BY MID/LATE MORNING AND INTO THE AFTERNOON...THE MOST INTENSE FORCING WILL MOVE IN ALONG WITH A MID LEVEL DRY PUNCH. THIS LOOKS TO DRIVE A INTENSE SQUALL LINE. DM WINDS...SOME HIGH END...WILL BE POSSIBLE ALONG WITH TORNADOES AND HAIL WITH ANY BOWING SEGMENT. BY 3-7 PM...ACTIVITY SHOULD PUSH EAST AND THEN OUT OF THE AREA IT IS NOT OFTEN ONE FEELS CONFIDENT IN USING SUCH STRONGLY WORDED STATEMENTS IN A FORECAST. HOWEVER...THIS CASE SEEMS TO FIT AS ALL INDICATIONS...ALONG WITH LOCAL SVR WEATHER CHECKLIST OUTPUT...SUPPORT A HIGH END/SIGNIFICANT EVENT. WHILE THERE MAY BE LIMITING FACTORS...THERE ARE NOT MANY.

...

Wednesday, April 21, 2010

Quiet Start to Severe Weather Season


Graphic courtesy of Sciencenews.org
Thus far, the Spring severe weather season has been relatively quiet in Alabama. Don't let that cause you to let your guard down, however. A new study by Greg Carbin of the SPC illustrates that "making a prediction of tornado activity in May, based on the character of the season to date through April, would be a tricky bet."

A potentially strong severe weather outbreak is certainly possible in the South later this week. The NWS Jackson, Mississippi is particularly concerned about a potential outbreak Friday afternoon through Saturday. Although predicting specifics this far in advance are very difficult, Jackson's morning forecast discussion today indicated that they are expecting a "high end" type severe threat. The SPC, in their latest Day4-8 outlook stated that widespread severe weather seems likely in portions of Arkansas, Louisiana, Mississippi, Western Tennessee, and NW Alabama Friday into Saturday.

Although 2010 has been relatively quiet in regard to severe weather in Alabama so far, that is not to say there hasn't been any. The NWS Birmingham has posted their Storm Data article for January 2010 here.

One final note:

There was an interesting article in ScienceNews.org recently which cited a study by Michael Frates of the University of Akron in Ohio that points out that the "tornado alley" of the Plains is not necessarily the location of the greatest number of strong to violent tornadoes.

...

Friday, April 16, 2010

Thursday, April 15, 2010

A Dry, Quiet April


NOAA Aviation Weather Center Water Vapor Image

Alabama has now gone seven days without any rainfall, much less severe weather, here in the middle of April. There is a slight chance for a brief shower Saturday, but that will amount to little, if anything. It now looks like we very well may go another week or so before rain chances return to the state.

The reason for this that there has been a persistent high pressure ridge over the Eastern United States. The prospects for needed rain do seem to increase toward the end of the month.

...

Friday, April 09, 2010

Boring, But Nice Weather.....

I am issuing a "BWW" or "Boring Weather Warning" for the State of Alabama for the next seven days. Actually the weather will be quite nice, with highs in the 70's and 80's. We may see our last frost of the season tonight, but other than that the weather will be dry and pleasant.

Storm chasers may not like it. But for those who were complaining about overcast skies and the unseasonably cold temperatures that seemed to stick with us most of the winter, it will be a gorgeous weather week in Alabama. Enjoy!

...

Tuesday, April 06, 2010

Decatur, AL Rainbow, 3/25/10



Awesome rainbow picture taken by my co-worker, Whitney Weatherford.

I was out looking at storms, so I missed this one. Thanks to Whitney for capturing it and allowing me to share it!

...

Thursday, April 01, 2010

I Was Called a Weather Weenie....



First and foremost, in this week's WeatherBrains netcast, listen to J.B. Elliott's "Miss Kitty" story! On a personal note, it was quite an honor to be mentioned by James Spann, Dr. Tim Coleman, J.B. Elliott, Kevin Selle, and Bill Murray toward the end of this week's (3/30/10) WeatherBrains Podcast. They all said some very kind words about me. If you get a chance to check it out, the part where I am mentioned is at the 1:05-1:08 point. I have even been invited to be a guest panelist for the week of May 17! I am looking forward to it.

Now that I am done "tooting my horn", I highly recommend this netcast to anyone who is interested in weather. I have listened to all 218 episodes. It is very entertaining and educational.

...

April 1, 1974 Alabama Killer Tornadoes


4/2/74 Huntsville Times



Path of 4/1/1974 Huntsville, AL F3 (Map by Tornado History Project)


On April 1, 1974, an intense low pressure system formed over the Plains and moved eastward toward the Mississippi and Ohio Valleys. Combined with a large mass of moist air, several tornadoes were spawned the South on April 1st and 2nd. At 9:40 p.m. on the 1st, an F3 tornado killed one and injured six in Huntsville. It was estimated to be 800 yards wide and travelled 8.4 miles. It tore down the WAAY AM 1550 tower. According to the Huntsville NWS, "this tornado moved NE, then SE across the western part of Huntsville. The Sherwood and Research Park sections suffered severe damage as homes were unroofed and walls were blown down. The casualties were in trailers north of Huntsville."


F2 tornadoes also touched down in Tuscaloosa and Blount Counties that day, injuring six in Tuscaloosa and 11 in Blount County. The Tuscaloosa tornado touched down at 5:05 p.m. and was on the ground for 16 miles across the northern part of the county, ending up near Samantha. The Blount County tornado touched down at 9:30 p.m. and was on the ground for 16 miles, from Hayden to Oneonta. In addition to the three tornadoes, severe thunderstorms containing damaging winds occurred in Limestone, Cullman, Blount, Etowah, and Calhoun counties. Golf ball-sized hail (1.75") was reported in Pickens, Fayette, Tuscaloosa, and Jefferson counties. Quarter-sized hail (1.00") was also reported in Jefferson and Etowah counties. This information was collected from the NOAA NCDC page. Property damage in these storms was estimated at $3 million. ...


...