Tuesday, October 16, 2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 161254
SWODY1
SPC AC 161252

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0752 AM CDT TUE OCT 16 2007

VALID 161300Z - 171200Z

..THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF WRN AND NW TX...

..SYNOPSIS...
NW IA UPR LOW EXPECTED TO DEAMPLIFY AS IT CONTINUES NNE TO WRN LK
SUPERIOR THIS PERIOD...WHILE LEAD IMPULSE IN FAST WNWLY JET ACROSS
THE E PACIFIC SWEEPS RAPIDLY E FROM THE SRN CA CST TO THE SRN HI
PLNS. SFC LOW ASSOCIATED WITH IA TROUGH SHOULD FILL AS IT LIFTS N
INTO MN. FRONT TRAILING ESE FROM LOW INTO IL WILL...HOWEVER...
LIKELY RETAIN SOME DEGREE OF IDENTITY AS IT MOVES E/NE INTO PARTS OF
WI/MI AND IND. FARTHER S...SWRN END OF SAME FRONT LIKELY WILL
BECOME INDISTINCT ACROSS THE LWR MS VLY AND E TX AS LEE CYCLOGENESIS
OVER THE CNTRL HI PLNS RESULTS IN WARM FRONTOGENESIS TONIGHT/EARLY
WEDNESDAY OVER W TX.

..LOWER MI INTO IND/OH...
MID/UPR-LVL LVL DRYING WILL SPREAD NNE INTO PARTS OF WI...LWR MI AND
IND TODAY AS IA UPR LOW OPENS INTO A NEGATIVE TILT TROUGH. SOMEWHAT
BROADER WARM SECTOR /RELATIVE TO YESTERDAY IN NEB AND IA/ MAY ALLOW
FOR SOME BREAKS IN BOUNDARY LAYER CLOUDS...AND MODEST SFC HEATING...
ALONG LOW LVL MOISTURE AXIS OVER SE WI/SW LWR MI AND NRN IND.

COUPLED WITH COOL MID LVL TEMPERATURES /AROUND -16C AT 500 MB/ AND
FORCING FOR ASCENT PROVIDED BY UPR LVL VORT LOBE NOW IN IA... SETUP
MAY SUPPORT A BAND OR TWO OF LOW-TOPPED AFTN/EVENING STORMS ALONG
PREVIOUSLY-MENTIONED SFC FRONT. WEAK SFC-BASED INSTABILITY /SBCAPE
AROUND 500 J PER KG/ AND 30-35 KT DEEP UNIDIRECTIONAL SWLY SHEAR
SUGGEST POTENTIAL FOR A FEW SUSTAINED UPDRAFTS WITH MARGINALLY
SEVERE HAIL AND/OR LOCALLY STRONG WINDS.

..W TX INTO SW OK...
LATEST SATELLITE/SFC/PROFILER AND VWP DATA SUGGEST THAT COLD FRONT
ASSOCIATED WITH IA UPR LOW HAS BEGUN TO REDEVELOP N ACROSS CNTRL AND
W TX THIS MORNING IN RESPONSE TO FALLING PRESSURES IN ERN CO.
40-50 KT SLY LLJ WILL BECOME ESTABLISHED OVER WRN PORTIONS OF THE
SRN AND CNTRL PLNS THIS EVENING AS CA UPR DISTURBANCE APPROACHES
REGION.

COMBINATION OF INCREASING LARGE SCALE ASCENT/WAA AND MOISTURE INFLUX
BENEATH EML PLUME SWEEPING E FROM THE SRN PLATEAU SHOULD LEAD TO
TSTM DEVELOPMENT ALONG NW FRINGE OF MOIST AXIS...POSSIBLY AS EARLY
AS THIS EVENING INVOF THE TX/NM BORDER. THIS ACTIVITY SHOULD
INCREASE IN COVERAGE AND SPREAD NE ALONG DEVELOPING WARM FRONT INTO
OK TONIGHT/EARLY WEDNESDAY AS UPR SYSTEM CONTINUES RAPIDLY EWD.

GIVEN INCREASING DEGREE OF INSTABILITY /MUCAPE TO 1000 J PER KG/
WITH STRENGTHENING ASCENT AND DEEP SHEAR...SETUP MAY SUPPORT A FEW
SUSTAINED STORMS/POSSIBLE SUPERCELLS WITH HAIL. AND...GIVEN THE
TIME OF DAY AND CHARACTER OF FORCING...MOST OF THIS ACTIVITY LIKELY
WILL BE SLIGHTLY ELEVATED. A LIMITED POTENTIAL
WILL...HOWEVER...EXIST FOR A FEW SFC- OR NEAR SFC-BASED STORMS THAT
MAY POSE A BRIEF TORNADO THREAT GIVEN EXPECTED EFFECTIVE SRH VALUES
OF 250-350 M2/S2.

.CORFIDI/GUYER.. 10/16/2007

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