Tuesday, October 25, 2011

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 250529
SWODY1
SPC AC 250527

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1227 AM CDT TUE OCT 25 2011

VALID 251200Z - 261200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
FAST SWLY FLOW ALOFT WILL STRETCH FROM THE FOUR CORNERS STATES EWD
ACROSS THE PLAINS AND TO THE ATLANTIC COAST AS AN UPPER TROUGH SINKS
SWD INTO THE GREAT BASIN...AND HEIGHTS RISE OVER THE E.

AT THE SURFACE...LOW PRESSURE WILL MOVE FROM THE CNTRL PLAINS INTO
THE MID MS VALLEY BY 00Z...WITH A COLD FRONT TRAILING SWWD FROM THE
IA/IL BORDER INTO SRN KS/WRN NW OK BY 00Z. AHEAD OF THIS
FRONT...WEAK MOISTURE RETURN WILL OCCUR WITH DEWPOINTS ONLY IN THE
LOWER TO MID 50S F AT BEST. THIS FRONT WILL SERVE AS A FOCUS FOR
SCATTERED THUNDERSTORMS...A FEW OF WHICH MAY CONTAIN MARGINAL HAIL
AND WIND...CONTINUING EWD OVERNIGHT FROM NERN OK INTO INDIANA AND
WRN OH BY WED MORNING.

...IL/IND/OH INTO MO...KS...OK...
RATHER WEAK LOW LEVEL LAPSE RATES WILL EXIST ACROSS THE WARM
SECTOR...EVEN BY PEAK HEATING WITH FORECAST SOUNDINGS SUGGESTING MU
PARCELS WILL BE ELEVATED AT AROUND 850 MB. EVEN SO...FORCING WILL
INCREASE ESPECIALLY NEAR THE LOW CENTER WITH STORMS EXPECTED TO
ERUPT OVER MUCH OF NRN IL BY 00Z. COOL TEMPERATURES ALOFT AS WELL AS
SOME WIND SHEAR WILL AID IN SMALL TO MARGINALLY SEVERE HAIL
DEVELOPMENT. MEAN FLOW THROUGH THE STORM WITH BE STRONG...WITH 50-60
KT WINDS HELPING TO INDUCE SURFACE GUST POTENTIAL. THESE STORMS ARE
LIKELY TO PERSIST IN SOME FORM AS THEY TRAVEL INTO INDIANA AND OH
OVERNIGHT WITH A CONTINUED THREAT.

TO THE SW...FORCING WILL BE WEAKER...FOCUSING ON THE FRONT MAINLY
AFTER 00Z. PERSISTENT COOLING ALOFT AND LIFT NEAR THIS FRONT MAY
HELP TO PRODUCE ISOLATED STRONG TO SEVERE THUNDERSTORMS...WITH
MAINLY A MARGINAL HAIL THREAT...FROM NERN OK INTO SRN MO.

...NRN AZ...
RELATIVELY STRONG FLOW ALOFT AND MARGINAL MID LEVEL LAPSE RATES WILL
OVERSPREAD AZ AS UPPER HEIGHTS FALL DURING THE DAY. SWLY UPSLOPE
FLOW INTO THE RIM WILL HELP TO PRODUCE SCATTERED STORMS...A FEW OF
WHICH COULD PRODUCE SMALL AND MAINLY SUB-SEVERE HAIL.

..JEWELL/HURLBUT.. 10/25/2011

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