DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 111628
SWODY1
SPC AC 111626

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1126 AM CDT FRI MAY 11 2007

VALID 111630Z - 121200Z

..NO SVR TSTM AREAS FORECAST...

..SYNOPSIS...
SLOW MOVING UPPER LOW WILL CONTINUE TO SHIFT EWD ACROSS THE LOWER MS
RIVER VALLEY TODAY...WITH RIDGING BUILDING NWD OVER THE ROCKIES.
LOW AMPLITUDE SHORTWAVE TROUGHS WILL EJECT NEWD ACROSS THE PAC NW
AND THEN SHIFT EWD ATOP THE RIDGE AXIS OVER THE NRN ROCKIES AND NRN
PLAINS THROUGH THE PERIOD.

..NRN PLAINS INTO THE CENTRAL HIGH PLAINS...
NNELY SURFACE FLOW IN WAKE OF THE UPPER LOW OVER LA WILL CONTINUE TO
HINDER GULF MOISTURE RETURN ACROSS THE CENTRAL U.S. TODAY. THIS
WILL INHIBIT AVAILABLE INSTABILITY AND RESULTANT SEVERE THREAT NEAR
THE FAST MOVING NRN STREAM IMPULSES...DESPITE RELATIVELY STRONG
SHEAR IN PLACE. DEEP MIXING AND UPSLOPE FLOW MAY ALLOW DEVELOPMENT
OF A FEW THUNDERSTORMS LATER TODAY OVER PARTS OF SRN MT INTO THE
CENTRAL HIGH PLAINS. ADDITIONAL STORMS MAY FORM FARTHER EAST NEAR
WEAK SURFACE LOW/FRONT INTO SD BY THE EARLY EVENING. THIS AREA WILL
REMAIN ALONG PERIPHERY OF STRONGER WLY FLOW ALOFT AND SHOULD HAVE
SUFFICIENT SHEAR FOR STORM-SCALE ORGANIZATION WITH ENSUING
THUNDERSTORMS TODAY. HOWEVER...CONSIDERABLE UNCERTAINTY REGARDING
INITIATION AND AVAILABLE INSTABILITY WARRANTS ONLY LOW SEVERE
PROBABILITIES ATTM. LATER TONIGHT...MODELS ARE CONSISTENT IN
INCREASING SSWLY LLJ ACROSS THE MID MO RIVER VALLEY. THIS WILL
LIKELY SUPPORT INCREASE IN ELEVATED THUNDERSTORMS N-NE OF SURFACE
FRONT INTO ERN SD/SWRN MN. HAIL MAY ACCOMPANY STRONGER CORES LATE
TONIGHT...THOUGH MUCAPE IS FORECAST TO REMAIN AOB 1000 J/KG AND
RESULTANT SEVERE THREAT APPEARS LOW.

..ERN TX/OZARKS INTO THE CENTRAL/SRN APPALACHIANS...
AIR MASS REMAINS QUITE MOIST ACROSS THE REGION AND SHOULD SUPPORT
LARGE AREA OF MODERATE INSTABILITY AND WEAK CIN BY THE EARLY
AFTERNOON. CLUSTERS/BANDS OF STORMS WILL LIKELY BECOME NUMEROUS
AGAIN TODAY ACROSS THIS REGION...NEAR AND SOUTH OF A SLOW SWD MOVING
COLD FRONT FROM THE CENTRAL APPALACHIANS ACROSS THE MID SOUTH.
HOWEVER...COMBINATION OF WEAK LAPSE RATES AND WEAK SHEAR IS EXPECTED
TO LIMIT SEVERITY OF AFTERNOON THUNDERSTORMS ACROSS THIS REGION.

.EVANS/LEVIT.. 05/11/2007

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