[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 181731
SWOMCD
SPC MCD 181730 
FLZ000-GAZ000-ALZ000-181930-

MESOSCALE DISCUSSION 0542
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT TUE APR 18 2006

AREAS AFFECTED...PORTIONS OF ERN AL...SWRN GA AND THE FLA PANHANDLE

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 181730Z - 181930Z

ISOLATED SVR TSTMS MAY OCCUR ALONG A STATIONARY BOUNDARY EXTENDING
FROM ECENTRAL AL SWD INTO SWRN GA AND ERN FLA PANHANDLE BY 20Z. AREA
WILL BE MONITORED FOR A POSSIBLE WW.

17Z VIS SAT IMAGERY SHOWS TOWERING CU ALONG A BOUNDARY THAT EXTENDED
ROUGHLY FROM 25 E BHM TO 40 W ABY TO 15 E TLH. DESPITE VERY WEAK TO
MINIMAL CINH REMAINING PER MODIFIED 12Z BMX AND RECENT RUC
SOUNDINGS...WEAK CONVERGENCE HAS AS YET PREVENTED TSTM DEVELOPMENT.
THE GREATEST PROBABILITY FOR INITIAL TSTM DEVELOPMENT IS OVER THE
FAR SWRN GA/ERN FLA PANHANDLE WHERE CONVERGENCE WAS SLIGHTLY GREATER
AS ANOTHER BOUNDARY MOVES WWD ACROSS THE AREA AND INTERSECTS THE
INITIAL STATIONARY BOUNDARY. REGARDLESS...GIVEN CONTINUED DAYTIME
HEATING AND DESTABILIZATION AT LEAST ISOLATED TSTM DEVELOPMENT IS
EXPECTED ALONG THE MAIN STATIONARY BOUNDARY BY 20Z. ALTHOUGH 1-4 KM
FLOW REMAINS RATHER WEAK PER RECENT VWP DATA...MODERATE NWLY 4-9 KM
FLOW /STRONGEST ABOVE 6 KM/ MAY BE SUFFICIENTLY STRONG TO FAVOR
STORM TOP VENTILATION. COMBINED WITH WEAK ELY FLOW ON THE EAST SIDE
OF THE STATIONARY BOUNDARY...SOME STORM ROTATION APPEARS LIKELY.
ALTHOUGH LAPSE RATES INITIALLY ARE RELATIVELY POOR /6-6.5 DEG C/KM /
SLIGHT MID LVL COOLING SHOULD AID IN STEEPENING LAPSE RATES THROUGH
THE AFTERNOON. WITH MODERATE INSTABILITY /MLCAPES AROUND 2000 J/KG /
MARGINALLY SVR HAIL WILL BE POSSIBLE. ADDITIONALLY...STEEP LOW LEVEL
LAPSE RATES /25 DEG T/TD SPREADS AT THE SFC/ MAY SUPPORT DMGG WIND
GUSTS AS WELL.

..CROSBIE.. 04/18/2006

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FFC...TAE...BMX...MOB...

31648422 32898534 33738608 33638653 32648656 31368589
30558533 30268476 30178385 30678348 

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