Thursday, January 21, 2010

Forecast Discussion NWS HUN

Here is an excerpt from the 11:04 a.m. Area Forecast Discussion by the NWS Huntsville, Alabama:

THE MAIN ISSUE FOR THIS AFTN AND EVENING IS SEVERE POTENTIAL.AMPLE HEATING IS ANTICIPATED AHEAD OF THE APPROACHING SHORTWAVEACROSS AR WHILE THE STRONG MID LEVEL JET SHOULD INCREASE LAYER BULKSHEAR VALUES THIS AFTN. STEEP LOW TO MID LEVEL LAPSE RATES ANDDROPPING FZL`S INDICATE A THREAT FOR STRONG UPDRAFTS AND HAILPOTENTIAL... WHILE SHEAR PROFILES WILL BE STRONG ENOUGH TO PROMOTESUPERCELL CONVECTION. THE NAM IS DOING A POOR JOB RESOLVING THE LOWLEVEL HEATING ALREADY UNDERWAY... AND IS FORECASTING AN INVERSIONTHAT APPEARS TOO STRONG THROUGH THE DAY. MODIFIED NAM SOUNDINGSUSING FCST TEMPS AND DEEPER LOW LEVEL MIXING INDICATE STRONGINSTABILITY FOR JANUARY BY 21-00Z. SB LIS OF -6 TO -8 AND SB CAPEVALUES OF 1.5K+ J/KG ARE PROGGED. COMBINED WITH 0-1KM SRH OF150-200 M2/S2...THE THREAT FOR LOW TOPPED SUPERCELLS REMAINS FAIRLYGOOD IF CONVECTION CAN DEVELOP. 0-1KM EHI VALUES OF 1-2 UNITS LATETHIS AFTN POINT TO THIS POTENTIAL AS WELL. THE TRIPLE POINT OF THEWARM FRONT/MODEST DRY LINE WILL BE SITUATED NEAR THE KHSV VCNTYAROUND 00Z...WITH CONVERGENCE ALONG THE BOUNDARY IN A NW-SEFASHION....

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