Friday, March 30, 2012

MESO: Mesoscale Discussion 0389

ACUS11 KWNS 301813
SWOMCD
SPC MCD 301812
OHZ000-KYZ000-INZ000-ILZ000-301945-

MESOSCALE DISCUSSION 0389
NWS STORM PREDICTION CENTER NORMAN OK
0112 PM CDT FRI MAR 30 2012

AREAS AFFECTED...WRN/CNTRL OH...CNTRL/SRN IND...SRN IL

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 301812Z - 301945Z

THUNDERSTORM DEVELOPMENT IS FORECAST TO TAKE PLACE DURING THE NEXT
FEW HRS ACROSS PORTIONS OF WRN OH SWWD INTO CNTRL IND AND SRN IL.
SVR STORMS WILL BE PROBABLE...AND A WW ISSUANCE WILL LIKELY BE
NEEDED BY 19-20Z.

MIDDAY MESOANALYSIS PLACES AN AREA OF SURFACE LOW PRESSURE OVER NWRN
IND AT 17Z...WHICH IS COINCIDENT WITH A MIDLEVEL IMPULSE MOVING E
ACROSS LK MI. WARM SECTOR AIRMASS...CHARACTERIZED BY TEMPERATURES
WARMING INTO THE MID TO UPR 70S WITH DEWPOINTS FROM THE MID 50S TO
LOW 60S...IS BOUNDED BY A COLD FRONT EXTENDING SWWD INTO CNTRL/SRN
MO...AND A WARM FRONT EXTENDING SEWD INTO ERN KY. STEEP MIDLEVEL
LAPSE RATES NEAR 8 C/KM RESIDE ABOVE THE DESTABILIZING WARM SECTOR
AIRMASS...AND WILL AID IN MLCAPE VALUES FROM 1000-1500 J/KG BY PEAK
HEATING. MEANWHILE...AS THE AFTERNOON PROGRESSES...THE SURFACE LOW
AND WARM FRONT WILL ADVANCE INTO OH...WHILE THE COLD FRONT DROPS
S-SEWD TOWARD SRN IND AND IL. THE COMBINATION OF CONVERGENCE AND
BOUNDARY LAYER DESTABILIZATION ALONG THE FRONT...AS WELL AS WEAK
LARGE-SCALE ASCENT ASSOCIATED WITH THE PREVIOUSLY MENTIONED UPPER
WAVE...SHOULD BE SUFFICIENT FOR THUNDERSTORM INITIATION ALONG THE
COLD FRONT...PERHAPS AS EARLY AS 19-20Z BASED ON RECENT RUNS OF THE
HRRR.

MIDLEVEL WLYS RANGE FROM 50 KT NEAR THE LK MI IMPULSE...TO 20-30 KT
OVER SRN IL...AND WILL YIELD SUFFICIENTLY STRONG DEEP-LAYER VERTICAL
WIND SHEAR /I.E. 0-6 KM BULK WIND DIFFERENCE FROM 20-40 KT/ FOR
ORGANIZED MULTICELL AND SUPERCELL STORM DEVELOPMENT. GIVEN THE
LINEAR NATURE OF LOW-LEVEL FORCING ALONG THE COLD FRONT...STORMS MAY
TEND TO ORGANIZE INTO LINE SEGMENTS...AND WILL POSE A THREAT FOR
DAMAGING WINDS AND LARGE HAIL. CLOSER TO THE SURFACE LOW AND WARM
FRONT OVER IND AND OH...SURFACE WINDS WILL BE MORE STRONGLY
BACKED...WHICH WILL MAXIMIZE LOW-LEVEL VERTICAL WIND SHEAR /0-1 KM
SRH AOA 150 M2 S-2/...AND INCREASE THE POTENTIAL FOR TORNADOES.

..GARNER.. 03/30/2012

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

ATTN...WFO...CLE...ILN...LMK...IWX...IND...PAH...ILX...LSX...

LAT...LON 41168501 41178263 39738277 37788809 37678948 38269010
39318941 41168501

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