SPC AC 270558
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT TUE OCT 27 2009
VALID 271200Z - 281200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
MODELS ARE IN GOOD AGREEMENT WITH THE EVOLUTION OF THE MID/UPPER
LEVEL PATTERN ACROSS THE CONUS TODAY/TONIGHT AS A LARGE...COLD
TROUGH CURRENTLY MOVING INTO THE NWRN U.S. PER WATER VAPOR IMAGERY
AMPLIFIES SSEWD THROUGH CA/GREAT BASIN TO SWRN STATES. THE DIGGING
OF THIS SYSTEM WILL RESULT IN THE SHORTWAVE TROUGH OVER THE SRN
PLAINS TO EJECT NEWD THROUGH THE LOWER MS VALLEY/MID SOUTH AS A
NEGATIVELY TILTED TROUGH. THIS SYSTEM SHOULD DE-AMPLIFY TUESDAY
NIGHT AS IT PROGRESSES DOWNSTREAM TO THE UPPER OH VALLEY/CENTRAL
APPALACHIANS BY 12Z WEDNESDAY.
IN THE LOW LEVELS...A WEAK SURFACE WAVE SHOULD TRACK INLAND ACROSS
THE ERN FL PANHANDLE BY LATE MORNING/EARLY AFTERNOON AND THEN TRACK
NEWD REACHING CENTRAL SC DURING THE EVENING BEFORE PROGRESSING NEWD.
THE MORE INLAND TRAJECTORY OF THE SRN PLAINS UPPER TROUGH AND THE
LACK OF STRONGER FORCING FOR ASCENT ACROSS THE SERN U.S. TODAY
SHOULD PRECLUDE THE AFOREMENTIONED SURFACE WAVE FROM BECOMING MORE
SUBSTANTIAL/DEEPER.
...ERN FL PANHANDLE INTO SRN GA...
SSWLY LLJ WILL BE STRENGTHENING AND SPREADING INLAND ACROSS THE ERN
FL PANHANDLE AND SWRN GA AT 12Z TODAY SUPPORTING A MOISTENING OF THE
BOUNDARY LAYER ACROSS THIS REGION. EXTENSIVE CLOUDINESS/
PRECIPITATION AS A RESULT OF LOW LEVEL MOISTURE/WARM AIR ADVECTION
AND WEAK LAPSE RATES ARE EXPECTED TO PRECLUDE THE DEVELOPMENT OF
STRONGER INSTABILITY ACROSS THIS REGION TODAY. A VEERING 30-40 KT
LLJ BENEATH 40-50 KT SWLY MID LEVEL WINDS WILL SUPPORT EFFECTIVE
BULK SHEAR SUFFICIENT FOR STORM ORGANIZATION. ALTHOUGH WEAK
INSTABILITY AND WEAK UPPER FORCING WILL LIKELY PRECLUDE GREATER
STORM COVERAGE...THE 00Z 4 KM WRF-NMM SUGGESTS THE POTENTIAL FOR A
FEW STRONGER STORMS/SUPERCELLS TO MOVE INLAND ACROSS THE ERN FL
PANHANDLE TO SWRN GA LATE THIS MORNING INTO THE AFTERNOON. SOME OF
THIS ACTIVITY COULD REACH PARTS OF SOUTH CENTRAL-ERN GA. THUS...
LOW SEVERE PROBABILITIES FOR STRONG WIND GUSTS AND/OR AN ISOLATED
TORNADO ARE WARRANTED.
...PARTS OF CENTRAL/NRN FL PENINSULA INTO SERN GA...
ALTHOUGH SURFACE HEATING MAY BE GREATER ACROSS THE FL PENINSULA THAN
AREAS FARTHER NW TODAY...WEAK LAPSE RATES WILL ALSO LIMIT STRONGER
INSTABILITY FROM DEVELOPING. MODELS SUGGEST SHOWERS/TSTMS SHOULD
DEVELOP ACROSS CENTRAL/NRN PARTS OF THE PENINSULA BY MID-LATE
AFTERNOON ALONG A LOW LEVEL CONVERGENCE ZONE...AND SPREAD ENEWD
TOWARD THE FL EAST COAST AND SERN GA. EFFECTIVE BULK SHEAR /35-45
KT/ OVER NRN FL/SRN GA WILL SUPPORT STORM ORGANIZATION...BUT WEAK
INSTABILITY IS EXPECTED TO LIMIT THE COVERAGE OF SEVERE WEATHER.
THUS...HAVE INCLUDED LOW TORNADO AND SEVERE WIND PROBABILITIES FOR
NRN FL INTO SERN GA.
..PETERS/SMITH.. 10/27/2009
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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