DAY3SVR: Nws Storm Prediction Center Norman Ok

ACUS03 KWNS 050733
SWODY3
SPC AC 050731

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0231 AM CDT FRI OCT 05 2007

VALID 071200Z - 081200Z

..THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SRN AND CNTRL
PLAINS...

..SYNOPSIS...

UPPER TROUGH WILL CONTINUE EWD INTO THE SRN AND CNTRL HIGH PLAINS
LATE SUNDAY AFTERNOON AND SUNDAY EVENING. A STRONG VORT MAX IS
FORECAST TO ROTATE THROUGH BASE OF UPPER TROUGH AND EJECT NEWD INTO
THE CNTRL PLAINS OVERNIGHT. BAROCLINIC ZONE WILL EXTEND FROM THE
UPPER MS VALLEY SWWD INTO THE CNTRL PLAINS EARLY SUNDAY. NRN PART OF
FRONT WILL SHIFT SLOWLY SEWD DURING THE DAY. THIS BOUNDARY MAY STALL
OVER THE CNTRL PLAINS AS A SURFACE LOW DEVELOPS ALONG FRONT AND
SUBSEQUENTLY LIFTS NEWD THROUGH KS AND NEB OVERNIGHT. GFS AND NAM
SOLUTIONS ARE SIMILAR AND STRONGER WITH SRN VORT MAX EJECTING NEWD
THROUGH THE CNTRL PLAINS...WHILE THE ECMWF PLACES LESS EMPHASIS ON
SRN STREAM VORT MAX AND MAINTAINS A POSITIVE TILT. THIS PLACES SOME
UNCERTAINTY ON THIS FORECAST AND WILL THEREFORE INTRODUCE ONLY 15%
CONDITIONAL PROBABILITIES FOR THIS FORECAST PERIOD.

..SRN AND CNTRL PLAINS AREAS...

PARTIALLY MODIFIED GULF AIR WITH DEWPOINTS IN THE MID TO UPPER 60S
WILL PERSIST IN PRE-FRONTAL WARM SECTOR. OWING TO RELATIVELY WARM
AIR ALOFT...MID LEVEL LAPSE RATES ARE EXPECTED TO REMAIN MODEST. A
ZONE OF WIDESPREAD CLOUDS AND CONVECTION IS FORECAST TO BE ONGOING
WITHIN PLUME OF DEEPER MOISTURE ALONG WARM CONVEYOR BELT FROM PARTS
OF THE SRN AND CNTRL PLAINS. OTHER CONVECTION MAY BE IN PROGRESS IN
POST FRONTAL ZONE FROM WRN KS NEWD THROUGH PARTS OF THE CNTRL
PLAINS. BEST POTENTIAL FOR DESTABILIZATION WILL EXIST IN ZONE EAST
OF FRONT AND WEST OF PRE-FRONTAL CONVECTION FROM THE ERN TX AND OK
PANHANDLES INTO WRN OK AND SWRN KS. IN THIS REGION STEEPER LAPSE
RATES MAY DEVELOP AS THERMAL TROUGH ATTENDING EJECTING VORT MAX
INTERCEPTS LOW LEVEL THERMAL RIDGE. STORMS ARE EXPECTED TO DEVELOP
AND INTENSIFY WITHIN THIS ZONE OF DESTABILIZATION AS FORCING FOR
ASCENT INCREASES WITHIN CYCLONICALLY CURVED JET EXIT REGION.
VERTICAL SHEAR PROFILES WILL SUPPORT POTENTIAL FOR ORGANIZED SEVERE
STORMS INCLUDING SUPERCELLS AND BOWING SEGMENTS. ACTIVITY WILL LIFT
NEWD INTO KS AND SRN NEB DURING THE EVENING. SOME SEVERE POTENTIAL
MAY SPREAD INTO PART OF THE UPPER MS VALLEY OVERNIGHT. HOWEVER...THE
THREAT INTO THIS REGION APPEARS MORE LIMITED DUE TO EXPECTED
MARGINAL INSTABILITY.

.DIAL.. 10/05/2007

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