Tuesday, August 26, 2008

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 261257
SWODY1
SPC AC 261254

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0754 AM CDT TUE AUG 26 2008

VALID 261300Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SERN U.S....

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL AND NRN
PLNS...

...SYNOPSIS...
AMPLIFIED/PROGRESSIVE PATTERN WILL CONTINUE ACROSS SRN CANADA AND
THE NRN U.S. THROUGH WEDNESDAY...WHILE WEAK FLOW PERSISTS FROM CA TO
THE SRN PLNS. UPPER RIDGE WILL MOVE E OVER THE GRT LKS AS STRONG
SHORTWAVE TROUGH MOVES FROM THE NRN RCKYS ENE INTO MB/WRN ONTARIO.
IN THE SOUTHEAST...HYBRID REMNANT OF T.D. FAY EXPECTED TO FINALLY
ACCELERATE NEWD FROM NRN AL THIS MORNING TO ERN KY BY 12Z WEDNESDAY.


...SERN U.S./SRN APLCNS...
SATELLITE AND PRESSURE CHANGE DATA SUGGEST THAT REMNANT CIRCULATION
OF T.D. FAY IS FINALLY MOVING NEWD. ASSOCIATED WIND FIELD HAS BEEN
SLOW TO WEAKEN AND LIKELY WILL REMAIN SUFFICIENTLY STRONG TO POSE A
CONTINUED RISK FOR ISOLD TORNADOES AND LOCALLY DMGG WIND GUSTS AS
CONVECTION IN ITS VICINITY DIURNALLY STRENGTHENS THROUGH THE DAY.
THE GREATEST SVR RISK SHOULD EXIST FROM SW GA NEWD INTO N CNTRL AND
NERN GA...WHERE 30-35 KT SSWLY 850 MB JET WILL PERSIST ATOP WEAK BUT
VERY MOIST NEAR-SFC SSE FLOW. THE POTENTIAL FOR LOW LVL
SHOWER/STORM ROTATION MAY BE FURTHER ENHANCED WHERE NE-MOVING CELLS
ENCOUNTER WEAK STNRY FRONT/ TERRAIN-INDUCED BOUNDARY EXTENDING FROM
NRN GA E THROUGH THE SC PIEDMONT INTO SRN NC. WHILE AN ISOLD SVR
THREAT MAY PERSIST INTO TONIGHT IN THE CAROLINAS...THE THREAT SHOULD
BE MAINLY DIURNAL GIVEN CONTINUING PRESENCE OF WARM MID LVL
TEMPERATURES.

...NRN/CNTRL PLNS...
COLD FRONT ASSOCIATED WITH STRONG/PROGRESSIVE NRN STREAM TROUGH WILL
MOVE STEADILY E ACROSS MT TODAY...REACHING THE WRN DAKS BY AFTN.
THE FRONT WILL OVERTAKE MORE SLOWLY-MOVING LEE TROUGH AND CONTINUE
SE INTO THE MID MO VLY EARLY WEDNESDAY. STRONG EML
OVERSPREADING THE NRN/CNTRL PLNS SHOULD CAP THE REGION TO DEEP
CONVECTIVE DEVELOPMENT FOR MUCH OF THE DAY. BUT BY LATE AFTN...
EXPECT SCTD TSTMS TO FORM ALONG LEE TROUGH AS COLD FRONT OVERTAKES
THAT FEATURE IN THE PRESENCE OF STRONG SFC HEATING AND INCREASING
HI-LVL DIFFLUENCE.

HEATING OF NARROW CORRIDOR OF UPR 50S/LWR 60S F DEWPOINTS ALONG LEE
TROUGH WILL YIELD 1000-2000 J/KG SBCAPE...MAXIMIZED OVER WRN AND
CNTRL PARTS OF NEB/SD. THE STRONGEST MID/UPR LVL FLOW WILL LAG THE
COLD FRONT GIVEN CONFIGURATION OF UPR SYSTEM AND ITS ENE MOTION INTO
SRN CANADA. NEVERTHELESS...AMPLE /30-40 KT/ SW TO NWLY DEEP SHEAR
WILL EXIST FOR SUPERCELLS...ESPECIALLY DURING THE INITIAL PERIOD OF
STORM DEVELOPMENT. ULTIMATELY...HOWEVER... PROGRESSIVE NATURE OF
STRONG/DEEP FORCING FOR ASCENT SHOULD FAVOR EVOLUTION INTO BROKEN
LINEAR SEGMENTS THIS EVE. THE STORMS WILL HAVE THE POTENTIAL TO
PRODUCE BOTH SVR HAIL AND WIND. SEASONABLY STRONG UVV MAY ALLOW
CONVECTION IN ND TO PERSIST INTO LATE EVE BEFORE WEAKENING AS
ASSOCIATED FORCING/DPVA MOVES BEYOND LOW LVL MOISTURE AXIS INTO NW
MN. FARTHER S...A SEPARATE AREA OF STORMS/POSSIBLE MCS MAY MOVE SE
ALONG BROADER INSTABILITY GRADIENT INTO ERN PARTS OF
SD/NEB...SUPPORTED BY 30 KT SSWLY LLJ AND DIFFLUENT WNW FLOW ALOFT.

...AZ/FAR SRN NV/INTERIOR SRN CA...
DEEPLY MOIST ENVIRONMENT HAS BECOME ESTABLISHED OVER MUCH OF AZ AND
ADJACENT PARTS OF SRN NV/CA...IN PART DUE TO NEARBY PRESENCE OF
WEAKENING T.D. JULIO TO THE SOUTH. SCTD TO NUMEROUS STORMS SHOULD
FORM WITH AFTN HEATING ACROSS THE REGION TODAY. EFFECTS OF
YESTERDAY/S STORMS AND LINGERING CLOUDS SHOULD LIMIT ANY ASSOCIATED
THREAT FOR LOCALLY DMGG WIND IN ERN AND MUCH OF CNTRL AZ.
HOWEVER...A THREAT FOR STRONG OUTFLOW WINDS MAY DEVELOP OVER THE LWR
CO VLY IN WRN AZ...AND OVER SE CA/FAR SRN NV...WHERE MORE
SUBSTANTIAL HEATING WILL OCCUR AND WEAK NELY MID LVL FLOW WILL BE
PRESENT TO SUPPORT SW-PROPAGATING STORMS.

..CORFIDI/JEWELL.. 08/26/2008

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