Tuesday, March 29, 2011

MESO: Mesoscale Discussion 0309

ACUS11 KWNS 300041
SWOMCD
SPC MCD 300040
MSZ000-LAZ000-ARZ000-300215-

MESOSCALE DISCUSSION 0309
NWS STORM PREDICTION CENTER NORMAN OK
0740 PM CDT TUE MAR 29 2011

AREAS AFFECTED...SERN AR...NRN LA...NRN/CNTRL MS

CONCERNING...SEVERE THUNDERSTORM WATCH 74...

VALID 300040Z - 300215Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 74
CONTINUES.

ELEVATED THUNDERSTORMS...SOME EXHIBITING SUPERCELLULAR
CHARACTERISTICS...WILL CONTINUE TO MOVE E/NEWD ACROSS SVR TSTM WATCH
74 AS ISENTROPIC ASCENT ABOVE THE NEAR-SURFACE STABLE LAYER
PERSISTS. THE MOST ROBUST CONVECTIVE DEVELOPMENT OVER THE NEXT
COUPLE OF HOURS IS ANTICIPATED TO BE NEAR THE INTERSTATE 20
CORRIDOR...WHICH MARKS THE CONFLUENCE OF 850-MB SLY FLOW
TRANSPORTING MOISTURE NWD FROM THE GULF OF MEXICO AND MORE SWLY FLOW
AHEAD OF AN APPROACHING FRONT PER RUC ANALYSIS OUTPUT AND REGIONAL
PROFILER DATA.

THE KJAN SOUNDING AT 00Z INDICATED 1779 J/KG OF CAPE FOR A PARCEL
LIFTED FROM AROUND 850 MB...OWING....IN PART...TO STEEP LAPSE RATES
OF 7 C PER KM IN THE 700-500-MB LAYER. EVEN STEEPER MID-LEVEL LAPSE
RATES /8 C PER KM/ WERE FOUND UPSTREAM AT KLZK...DUE TO COLDER
MID-LEVEL TEMPERATURES ASSOCIATED WITH THE MID-LEVEL SHORTWAVE
TROUGH APPROACHING FROM THE PLAINS. THIS AMOUNT OF INSTABILITY WILL
CONTINUE TO SUPPORT STRONG/DEEP UPDRAFTS THROUGH THE EVENING...WHICH
WILL BE FURTHER ENHANCED BY EFFECTIVE BULK SHEAR MAGNITUDES OF 40 TO
50 KT ACCORDING TO 00Z RUC ANALYSIS. GIVEN THE ELEVATED NATURE OF
THE CONVECTION...LARGE HAIL WILL BE THE MAIN CONCERN...PARTICULARLY
WITH ANY SUSTAINED SUPERCELLS /AS NOTED WITH THE STORMS CROSSING THE
MS RIVER SOUTH OF VICKSBURG AND THE LEFT-MOVER APPROACHING THE
JACKSON AREA/.

..COHEN.. 03/30/2011

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

ATTN...WFO...MEG...JAN...SHV...

LAT...LON 32288892 32039063 31699268 31789355 32109392 32829387
32869289 33089183 33349126 33859061 34048980 33898852
33098841 32288892

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