SPC AC 021237
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0637 AM CST MON FEB 02 2004
VALID 021300Z - 031200Z
GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 WNW UKI 45 NNE SAC
60 S NFL 35 S P38 60 S SGU 35 W PRC 10 SW YUM.
GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 SSE SAV 50 NNW AYS
ABY 20 SSW CEW ...CONT... 20 SSW BPT 25 N BPT 40 N POE 20 WSW MLU
GWO 15 NE MSL 35 W CHA 40 N ATL AHN CLT 20 NNW RWI HSE.
...NO SVR TSTM AREAS FORECAST...
DOWNSTREAM OF SPLIT IN UPPER FLOW PATTERN OVER THE CENTRAL PACIFIC
...NORTHERN BRANCH REMAINS MOST PROMINENT BELT OF WESTERLIES
EASTWARD INTO THE UNITED STATES. A COUPLE OF HIGH AMPLITUDE TROUGHS
ARE CURRENTLY EMBEDDED WITHIN THIS REGIME...ONE OVER THE CENTRAL/
SOUTHERN PLAINS...THE OTHER NOW APPROACHING THE PACIFIC COAST.
MODELS SUGGEST LEAD TROUGH WILL TAKE ON INCREASINGLY NEGATIVE TILT
AND LIFT ACROSS THE LOWER/MIDDLE MISSISSIPPI AND TENNESSEE VALLEYS
TODAY...BEFORE CONTINUING INTO THE LOWER OHIO VALLEY AND CENTRAL
APPALACHIANS TONIGHT. THIS WILL OCCUR AS UPSTREAM TROUGH CONTINUES
TO DIG INLAND ACROSS CALIFORNIA.
...EAST OF ROCKIES...
LATEST WATER VAPOR IMAGERY INDICATES CENTRAL U.S. TROUGH IS COMPOSED
OF A COUPLE SMALLER SCALE SHORT WAVE TROUGHS. ONE IS NOW BEGINNING
TO LIFT OUT OF EAST TEXAS INTO THE LOWER MISSISSIPPI VALLEY...WHILE
THE OTHER IS DIGGING OUT OF THE NORTH CENTRAL ROCKIES INTO THE
CENTRAL PLAINS. MODELS SUGGEST SHORT WAVES WILL GRADUALLY MERGE
DURING THIS FORECAST PERIOD...WITH PRONOUNCED MID-LEVEL
SUBSIDENCE/DRYING OVERSPREADING THE GULF STATES LATER TODAY/TONIGHT
AS STRONGER LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION SHIFTS
AWAY...INTO THE UPPER OHIO VALLEY/MID ATLANTIC STATES.
ONGOING CONVECTIVE DEVELOPMENT OVER THE WESTERN GULF COASTAL AREAS
IS BEING SUPPORTED BY FORCING ASSOCIATED WITH LEAD SHORT WAVE
TROUGH. THIS FORCING IS PROGGED TO SPREAD ACROSS THE LOWER
MISSISSIPPI VALLEY BY MIDDAY...BEFORE STRONGER LIFT REDEVELOPS
EASTWARD IN LOW-LEVEL WARM ADVECTION REGIME OVER THE TENNESSEE
VALLEY.
DESPITE FAVORABLE DYNAMIC FORCING...MOISTURE INFLUX OFF THE STILL
MODIFYING WESTERN/CENTRAL GULF OF MEXICO APPEARS LIKELY TO REMAIN
WEAK OR NON EXISTENT DUE TO INCREASINGLY WESTERLY COMPONENT TO
LOW-LEVEL FLOW ACROSS THE GULF STATES EARLY TODAY. THIS WILL
STRONGLY LIMIT DESTABILIZATION...AND APPEARS TO BE PRIMARY
MITIGATING FACTOR WITH REGARD TO SEVERE THREAT. WEAK SURFACE-BASED
DESTABILIZATION MAY OCCUR NEAR THE SOUTHEAST LOUISIANA COAST THIS
MORNING...WHICH WILL SUPPORT SOME POTENTIAL FOR DAMAGING WINDS WITH
ONGOING CLUSTER. HOWEVER...STRONGEST ACTIVITY APPEARS LIKELY TO
REMAIN OFFSHORE...AND CLUSTER SHOULD WEAKEN THIS AFTERNOON AS
FORCING LIFTS NORTHEAST OF CENTRAL GULF COAST.
IN RESPONSE TO SHORT WAVE DIGGING ACROSS THE CENTRAL PLAINS INTO THE
MIDDLE MISSISSIPPI VALLEY...STRENGTHENING SOUTHWESTERLY LOW-LEVEL
JET MAY CONTRIBUTE TO SOME MOISTURE INCREASE AND ENHANCED ISENTROPIC
ASCENT ACROSS SOUTH CENTRAL ALABAMA INTO WEST CENTRAL GEORGIA. THIS
WILL OCCUR LATE THIS AFTERNOON INTO THE EVENING HOURS...AND MAY BE
ACCOMPANIED BY CONVECTIVE DEVELOPMENT...BEFORE INCREASING MID-LEVEL
CONVECTIVE INHIBITION ENDS THREAT. ANY THUNDERSTORMS THAT DO
DEVELOP WILL BE SUPPORTED BY WEAK CAPE FOR PARCELS LIFTED ABOVE
SURFACE/NEAR-SURFACE INVERSION LAYER...WHICH SHOULD PRECLUDE SEVERE
THREAT.
OVERNIGHT...MODELS INDICATE FORCING ASSOCIATED WITH LARGER-SCALE
UPPER TROUGH WILL SUPPORT DEVELOPING SURFACE LOW ACROSS THE
CAROLINAS. WHILE MOISTURE RETURN WILL ALSO BE VERY LIMITED ACROSS
THIS REGION...FORECAST SOUNDINGS SUGGEST DESTABILIZATION MAY BECOME
SUFFICIENT FOR SCATTERED WEAK THUNDERSTORM ACTIVITY... MAINLY ACROSS
EASTERN NORTH CAROLINA TOWARD 03/12Z.
...WEST OF ROCKIES...
MODELS INDICATE 500 MB COLD POOL...WITH TEMPERATURES AS LOW AS
-30C...ACCOMPANYING UPPER TROUGH APPROACHING THE CALIFORNIA COAST.
AS TROUGH PROGRESSES INLAND TODAY...COOLING ALOFT WILL CONTRIBUTE TO
DESTABILIZATION AND POTENTIAL FOR SCATTERED THUNDERSTORMS.
SCATTERED THUNDERSTORM ACTIVITY HAS ALREADY BEEN EVIDENT OFF THE
NORTHERN CALIFORNIA COAST ASSOCIATED WITH FORCING IN EXIT REGION OF
INITIAL MID/UPPER JET STREAK. THIS FEATURE IS PROGGED TO MIGRATE
ACROSS SOUTHERN CALIFORNIA INTO THE SOUTHERN GREAT BASIN DURING THE
DAY...WITH ANOTHER VIGOROUS JET PROGGED TO DIG OFF THE SOUTHERN
CALIFORNIA COAST LATER TODAY/TONIGHT. DESTABILIZATION ALONG THE
SOUTHERN CALIFORNIA COAST THIS EVENING WILL BE ENHANCED BY WEAK
MOIST ONSHORE FLOW...AND MODEL FORECAST SOUNDINGS SUGGEST
SURFACE-BASED CAPE MAY APPROACH 500 J/KG. GIVEN LOW FREEZING/WET
BULB ZERO LEVELS AND FAVORABLE SHEAR...ENVIRONMENT MAY BECOME
SUPPORTIVE OF A FEW CELLS PRODUCING HAIL NEAR SEVERE LIMITS.
..KERR.. 02/02/2004
...NOTICE...
FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3. THE
INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED FOR 1630Z
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