[SWODY2] SWODY2

[SWODY2 at goshenarc.org]

ACUS02 KWNS 081731
SWODY2
SPC AC 081729

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CST WED DEC 08 2004

VALID 091200Z - 101200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 15 SSW
CBM 30 NNW BHM 30 E LGC 35 SW MCN 15 E CEW MOB GPT MCB 15 SSW CBM.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 SSE BPT MLU DYR
OWB SDF 10 E LEX 15 S JKL 35 NE TRI LYH 20 N RIC 15 E SBY ...CONT...
15 E JAX 20 W CTY.

...THERE IS A SLGT RISK OF SVR TSTMS THURSDAY ACROSS PARTS OF THE
CNTRL/ERN GULF COAST STATES....

AMPLIFICATION IN LARGE-SCALE UPPER FLOW IS ALREADY EVIDENT IN LATEST
WATER VAPOR IMAGERY.  MODELS SUGGEST UPPER RIDGE...NOW BUILDING
ACROSS THE EASTERN PACIFIC...WILL CONTINUE TO NOSE NORTHEASTWARD
INTO THE CANADIAN ROCKIES/PACIFIC COAST STATES AND INTERMOUNTAIN
WEST THURSDAY/THURSDAY NIGHT.  AS THIS OCCURS...BROAD TROUGH...NOW
EVOLVING ACROSS THE PLAINS/MISSISSIPPI VALLEY...WILL DEEPEN
SHARPLY...WITH A DEEP CLOSED LOW PROGGED TO FORM ACROSS THE
MISSISSIPPI VALLEY THURSDAY NIGHT INTO EARLY FRIDAY.

CENTRAL U.S. TROUGH IS BEGINNING TO DEVELOP IN RESPONSE TO THE
PROGRESSION OF A COUPLE OF DISTINCT SHORT WAVE TROUGHS...ONE IN THE
SOUTHERN STREAM...THE OTHER IN THE NORTHERN STREAM.  SOUTHERN BRANCH
TROUGH IS ALREADY MIGRATING ACROSS THE SOUTHERN PLAINS...AND PROGGED
TO CONTINUE INTO THE LOWER MISSISSIPPI VALLEY BY EARLY
THURSDAY...BEFORE ACCELERATING NORTHEASTWARD ACROSS MID ATLANTIC
COASTAL AREAS BY LATE THURSDAY NIGHT.  NORTHERN BRANCH SYSTEM WILL
CONTINUE ACROSS THE NORTHERN INTERMOUNTAIN REGION AND ROCKIES
THROUGH EARLY THURSDAY...BEFORE DIGGING STRONGLY INTO THE
MISSISSIPPI VALLEY THURSDAY/THURSDAY NIGHT.

...CENTRAL GULF STATES...
IN RESPONSE TO LEAD...SOUTHERN TROUGH...A RETURN FLOW OF MOISTURE IS
FORECAST TO OCCUR FROM THE WESTERN GULF OF MEXICO INTO MUCH OF THE
CENTRAL/EASTERN GULF STATES...WITH SURFACE FRONTAL ZONE DEVELOPING
NORTHWARD INTO THE NORTHERN GULF STATES BY THE BEGINNING OF THE
FORECAST PERIOD.  INFLUX OF MOISTURE/ DESTABILIZATION AND
LARGE-SCALE FORCING ASSOCIATED WITH UPPER TROUGH IS EXPECTED TO
CONTRIBUTE TO FAIRLY BROAD AREA OF CONVECTIVE DEVELOPMENT BY EARLY
THURSDAY.  MUCH OF THE CONVECTIVE ACTIVITY LIKELY WILL BE OCCURRING
ABOVE FRONTAL INVERSION...NORTH OF SURFACE FRONT...FROM PARTS OF THE
UPPER TENNESSEE VALLEY INTO THE SOUTHERN APPALACHIANS. 
HOWEVER...ACTIVITY IS EXPECTED TO TRAIL SOUTHWARD INTO WARM SECTOR
ACROSS MISSISSIPPI/ LOUISIANA...WHERE MID-LEVEL FORCING SHOULD BE
SUFFICIENT TO WEAKEN INHIBITION.

WEAK MID-LEVEL LAPSE RATES...AND SHALLOW NOCTURNAL SURFACE-BASED
INVERSION LAYER...MAY INITIALLY BE INHIBITING SEVERE THREAT IN
STRONGLY SHEARED ENVIRONMENT ALONG 40 TO 50 KT SOUTHWESTERLY
LOW-LEVEL JET AXIS.  HOWEVER...WITH AT LEAST SOME HEATING...
MODIFYING BOUNDARY LAYER THROUGH THE MIDDAY/EARLY AFTERNOON HOURS IS
EXPECTED TO BECOME INCREASINGLY SUPPORTIVE OF SURFACE-BASED STORMS
AS ACTIVITY SPREADS EASTWARD.  A FEW SUPERCELLS APPEAR
POSSIBLE...NEAR OR WITHIN SQUALL LINE...WITH ASSOCIATED ENHANCED
RISK OF ISOLATED TORNADOES...IN ADDITION TO DAMAGING WIND GUSTS.

TENDENCY MAY BE FOR WEAKENING UPPER SUPPORT ACROSS THE CENTRAL/
EASTERN GULF STATES THROUGH THE AFTERNOON...PARTICULARLY IF LATEST
ETA SOLUTION VERIFIES CLOSER THAN GFS. HOWEVER...MOIST UNSTABLE
BOUNDARY LAYER WITH MIXED LAYER CAPE IN EXCESS OF 1000 J/KG LIKELY
WILL CONTINUE TO SUPPORT SEVERE THREAT UNTIL ONSET OF COOLING AFTER
DARK THURSDAY EVENING.

...SOUTH ATLANTIC COAST STATES...
FORCING ASSOCIATED WITH SOUTHERN BRANCH TROUGH APPEARS LIKELY TO
ENHANCE LARGE-SCALE ASCENT NEAR SURFACE FRONT ACROSS THE CENTRAL/
EASTERN CAROLINAS LATE THURSDAY AFTERNOON INTO THURSDAY EVENING. 
FRONT IS PROGGED TO DEVELOP INLAND LATER TONIGHT INTO THURSDAY...
WITH ASSOCIATED INCREASE IN BOUNDARY LAYER MOISTURE OFF THE WESTERN
ATLANTIC.  DESPITE LIKELIHOOD OF 60F+ SURFACE DEW POINTS IN WARM
SECTOR...EXTENSIVE CLOUD COVER IS EXPECTED TO LIMIT SURFACE HEATING.
 WITH MID-LEVEL LAPSE RATES LIKELY NOT TO STEEPEN
SIGNIFICANTLY...THIS WILL MINIMIZE POTENTIAL FOR STRONG
DESTABILIZATION.  HOWEVER...EVEN EXPECTED DEVELOPMENT OF WEAK
CONDITIONAL INSTABILITY WILL SUPPORT LOW PROBABILITY SEVERE THREAT
IN STRONG MEAN FLOW/SHEAR ENVIRONMENT.

..KERR.. 12/08/2004

...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.