[SWODY2] SWODY2

[SWODY2 at goshenarc.org]

ACUS02 KWNS 310631
SWODY2
SPC AC 310630

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1230 AM CST FRI DEC 31 2004

VALID 011200Z - 021200Z

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 WNW CLM 25 E AST
25 SW EUG 10 NW CEC.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 E PSX 35 WSW LFK
DAL 60 WSW SPS LTS DDC OLU MCW DBQ MTO 20 W EVV MKL GWO 30 E MCB 35
SE HUM.

...NO SVR TSTM AREAS FORECAST...

LITTLE CHANGE TO THE LARGE-SCALE PATTERN IS FORECAST THROUGH THIS
FORECAST PERIOD WITH POLAR LOW REMAINING CENTERED NORTHEAST OF
HUDSON BAY...WHILE SUBTROPICAL RIDGE REMAINS CENTERED OVER THE
SOUTHERN GULF OF MEXICO/CARIBBEAN.  A BROAD TROUGH WILL ALSO PERSIST
IN THE SUBTROPICAL WESTERLIES AND THE SOUTHERN BRANCH OF THE POLAR
WESTERLIES...FROM THE EASTERN PACIFIC THROUGH THE WESTERN/NORTHERN
U.S...WITH A NUMBER OF EMBEDDED...PROGRESSIVE SHORT WAVES.

ONE SHORT WAVE TROUGH IS ALREADY PROGRESSING OUT OF WESTERN TROUGH
INTO THE UPPER MISSISSIPPI VALLEY/GREAT LAKES REGION.  MODELS
SUGGEST THIS FEATURE WILL ACCELERATE ACROSS NORTH ATLANTIC COASTAL
AREAS BY EARLY SATURDAY...AHEAD OF SIGNIFICANT SHORT WAVE ROTATING
AROUND CANADIAN VORTEX.  THIS WILL BE ACCOMPANIED BY SOUTHWARD SURGE
OF MODIFIED ARCTIC AIR INTO THE NORTH CENTRAL/NORTHEAST STATES. 
DIFFERENCES AMONG THE MODELS EXIST WITH HOW THIS IS HANDLED...BUT
SHALLOW SURFACE FRONT APPEARS LIKELY AS FAR SOUTH AS THE OHIO VALLEY
AND SOUTH CENTRAL PLAINS BY EARLY SATURDAY.  THIS AIR MASS MAY BE
SLOWER TO MODIFY THAN INDICATED BY MODELS...BUT BOUNDARY IS EXPECTED
TO BECOME FOCUS FOR ANOTHER DEVELOPING SURFACE CYCLONE AS NEXT SHORT
WAVE TROUGH LIFTS OUT OF THE GREAT BASIN INTO THE UPPER MISSISSIPPI
VALLEY SATURDAY/SATURDAY NIGHT.

...CENTRAL PLAINS INTO MIDDLE MISSISSIPPI VALLEY...
LOW-LEVEL MOIST TONGUE WITH MID 50S/LOWER 60S DEW POINTS IS ALREADY
PRESENT ACROSS PARTS OF THE SOUTHERN PLAINS/LOWER MISSISSIPPI
VALLEY...AND SHOULD PERSIST THROUGH SATURDAY.  THIS WILL CONTRIBUTE
TO POTENTIAL FOR AT LEAST WEAK DESTABILIZATION SUFFICIENT FOR
CONVECTIVE DEVELOPMENT...AS LARGE-SCALE FORCING FOR UPWARD VERTICAL
MOTION INCREASES IN ASSOCIATION WITH DEVELOPING SURFACE WAVE.  THIS
APPEARS MOST LIKELY LATE SATURDAY AFTERNOON/EVENING FROM PARTS OF
EASTERN KANSAS INTO THE MIDDLE MISSISSIPPI VALLEY.  STRONGER
ISENTROPIC ASCENT AND LIFTING TO LEVELS OF FREE CONVECTION APPEAR
LIKELY TO OCCUR ABOVE SHALLOW SURFACE-BASED INVERSION LAYER.  GIVEN
WEAK CAPE...THERMODYNAMIC ENVIRONMENT IS NOT EXPECTED TO BECOME
SUPPORTIVE OF SEVERE THREAT DESPITE LIKELIHOOD OF FAVORABLY SHEARED
ENVIRONMENT.

...SOUTHERN PLAINS INTO LOWER MISSISSIPPI VALLEY...
SOUTHERN FRINGE OF STRONGER MID-LEVEL FORCING ASSOCIATED WITH SHORT
WAVE TROUGH MAY WEAKEN MID-LEVEL INHIBITION SUFFICIENTLY FOR
CONVECTIVE DEVELOPMENT TO THE SOUTH OF SURFACE FRONTAL ZONE.  FRONT
WILL SURGE DEEPER INTO THE SOUTHERN PLAINS SATURDAY NIGHT... IN WAKE
OF SURFACE LOW LIFTING INTO THE MID/UPPER MISSISSIPPI VALLEY.  A FEW
THUNDERSTORMS MAY DEVELOP NEAR DRY LINE/COLD FRONT LATE SATURDAY
AFTERNOON ACROSS PARTS OF NORTHERN TEXAS/OKLAHOMA.  HOWEVER...BETTER
CHANCE FOR ACTIVITY APPEARS TO EXIST TO THE EAST LATER SATURDAY
NIGHT...IN PROXIMITY TO SOUTHERLY LOW-LEVEL JET AXIS SHIFTING INTO
THE LOWER MISSISSIPPI VALLEY.  WITH CAPE LIMITED DUE TO MARGINAL
MID-LEVEL LAPSE RATES...TIMING OF DEVELOPMENT MAINLY AFTER
DARK...AFTER ONSET OF RADIATIONAL COOLING IN BOUNDARY
LAYER...CURRENTLY IS EXPECTED TO MINIMIZE SEVERE THREAT.

...WESTERN/CENTRAL GULF COAST...
FORCING ASSOCIATED WITH IMPULSE EMBEDDED WITHIN SUBTROPICAL
WESTERLIES COULD ENHANCE LIFT ASSOCIATED WITH LOW-LEVEL WARM
ADVECTION REGIME NEAR UPPER TEXAS AND LOUISIANA COASTAL AREAS LATE
SATURDAY NIGHT INTO EARLY SUNDAY.  HOWEVER...GIVEN WEAK LOW-LEVEL
SHEAR AND CONTINUING PRESENCE OF SURFACE RIDGING PROGGED BY MODELS
ACROSS THIS REGION...RISK OF SEVERE THUNDERSTORMS APPEARS MINIMAL AT
THE PRESENT TIME.

..KERR.. 12/31/2004

...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.