DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 011255
SWODY1
SPC AC 011253

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0753 AM CDT WED AUG 01 2007

VALID 011300Z - 021200Z

..THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON/EVENING FROM MN
TO CENTRAL NEB...

..NEB TO MN THIS AFTERNOON/EVENING...
A STRONG MID LEVEL TROUGH WILL TRANSLATE EWD FROM SASKATCHEWAN AND
MANITOBA TO ONTARIO...WHILE AN ASSOCIATED COLD FRONT MOVES SEWD
ACROSS MUCH OF MN/SD/NW NEB BY THIS EVENING. CONVECTION HAS BEEN
ONGOING OVERNIGHT NEAR THE FRONT...WITHIN A NARROW BELT OF MID LEVEL
MOISTURE EMANATING FROM SWRN MONSOONAL MOISTURE PLUME. EXPECT
ADDITIONAL THUNDERSTORM DEVELOPMENT BY MIDDAY/EARLY AFTERNOON ALONG
THE FRONT AND REMNANT OUTFLOW BOUNDARIES...WHERE INSTABILITY WILL BE
MAINTAINED BY DAYTIME HEATING AND BOUNDARY LAYER DEWPOINTS RANGING
FROM 65-70 F...BENEATH STEEP MID LEVEL LAPSE RATES FROM THE NRN
INTERMOUNTAIN REGION. MLCAPE VALUES SHOULD RANGE FROM ROUGHLY 1500
J/KG ACROSS MN TO 2500 J/KG IN CENTRAL NEB THIS AFTERNOON.

THE STRONGER MID LEVEL FLOW AND RESULTANT DEEP LAYER VERTICAL SHEAR
ARE EXPECTED TO REMAIN ON THE COOL SIDE OF THE SURFACE FRONT AND OUT
OF PHASE WITH THE WARM SECTOR. THUS...EFFECTIVE BULK SHEAR OF ONLY
20-25 KT WILL LIKELY SUPPORT MULTICELL CLUSTERS ALONG THE FRONT
BEGINNING BY ROUGHLY MIDDAY TO EARLY AFTERNOON...WITH CONVECTION
EXPECTED TO SPREAD SEWD ACROSS MN...AND SWD INTO NEB. DESPITE
PROXIMITY TO THE MID LEVEL WAVE...MORE UNIDIRECTIONAL WIND PROFILES
IN MN WILL NOT YIELD APPRECIABLY STRONGER VERTICAL SHEAR THAN IN
NEB...WHILE THE STRONGER INSTABILITY ACROSS NEB WILL LIKELY
COMPENSATE SOMEWHAT FOR THE WARMER TEMPERATURE PROFILES COMPARED TO
MN. THEREFORE...WILL EXTEND THE SLIGHT RISK AND LOW-END WIND/HAIL
PROBABILITIES SWWD INTO NEB GIVEN NO SUBSTANTIAL DIFFERENCES IN THE
SEVERE THREAT ALONG MUCH OF THE SURFACE FRONT.

..ELSEWHERE...
THE BROAD MONSOONAL MOISTURE PLUME AND SCATTERED DIURNAL
THUNDERSTORMS ARE EXPECTED AGAIN TODAY FROM THE SRN ROCKIES INTO THE
GREAT BASIN. FARTHER E...SCATTERED THUNDERSTORMS WILL OCCUR TODAY
ALONG THE REMNANT FRONTAL ZONE FROM THE SRN PLAINS SEWD TO THE NRN
GULF OF MEXICO AND CENTRAL/N FL.

.THOMPSON/GRAMS.. 08/01/2007

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