[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 071236
SWODY1
SPC AC 071234

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0634 AM CST SUN JAN 07 2007

VALID 071300Z - 081200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF AL/NRN GA ENEWD
TO MID ATLANTIC STATES...

AS IS FREQUENTLY THE CASE IN COOL SEASON SEVERE THREAT PATTERNS IN
THE SOUTHEAST...THE ONLY CAVEAT SEPARATING AN ACTIVE STORM DAY FROM
A NO SEVERE DAY IS AIR MASS BUOYANCY/INSTABILITY.  CURRENT SITUATION
IS TYPICAL AS A VERY STRONG TROUGH AND ASSOCIATED JET STRUCTURE
RAPIDLY SWINGS EWD ACROSS THE PLAINS TO THE TN/OH VALLEYS BY 12Z
MON.

IN THE WAKE OF THE PREVIOUS SYSTEM THE AIR MASS OVER THE GULF WAS
UNDISTURBED AND OVERNIGHT THERE HAS BEEN A DRAMATIC NWD RETURN OF
MOISTURE ALONG THE GULF COAST AS PRECIPITABLE WATER HAS RISEN TO
ABOVE 1.5 INCHES. WHILE THERE HAS BEEN A STEADY INCREASE IN
CONVECTIVE TYPE PRECIPITATION OVERNIGHT ACROSS THE GULF STATES IN
THE STRENGTHENING ISENTROPIC/WARM ADVECTION REGIME...THE WEAK LAPSE
RATES HAVE LIMITED THE BUOYANCY WITH LITTLE LIGHTNING NOTED THUS
FAR.

SURFACE LOW HAS DEVELOPED IN RESPONSE TO THE APPROACH OF THE STRONG
UPPER TROUGH AND WILL GRADUALLY DEEPEN FROM ITS CURRENT LOCATION
OVER WCENTRAL MS NEWD ACROSS MIDDLE TN TO WRN PA BY 12Z MON.

LOW/MID LEVEL JET ACROSS DEVELOPING WARM SECTOR AL/GA WILL INCREASE
TO 50-60KT AS 100PLUS KT 500 MB POLAR JET SHIFTS EWD INTO TN/OH
VALLEYS BY THIS EVENING.

SHEAR PROFILES WILL BE VERY SUPPORTIVE OF ROTATING STORMS WITH
SFC-1KM SHEAR INCREASING TO 40KT OR GREATER THIS AFTERNOON AND
TONIGHT.

MID 60 F DEWPOINTS WILL SPREAD INLAND BY THIS AFTERNOON AS FAR N AS
CENTRAL AL/NRN GA AND ERN CAROLINAS.  EVEN THOUGH THE WEAK LAPSE
RATES AND MINIMAL DAYTIME HEATING WILL GENERALLY LIMIT MLCAPES TO
500 J/KG...THE STRENGTH OF THE SYSTEM COUPLED WITH THE UNSEASONABLY
MOIST AIRMASS REQUIRES AN EXPANSION OF THE PRIMARILY CONDITIONAL
SEVERE RISK AREA WWD INTO AL.

LOW TOPPED SUPERCELLS WILL BECOME AN INCREASING CONCERN BY EARLY/MID
AFTERNOON CENTRAL AL/GA SPREADING NEWD INTO CAROLINAS TONIGHT IN THE
 DEVELOPING WARM SECTOR.  ADDITIONALLY MORE SYNOPTICALLY FORCED LINE
SEGMENTS WILL DEVELOP ALONG/AHEAD OF COLD FRONT NOW NOTED FROM THE
SURFACE LOW SWWD TO SWRN LA.

A TORNADO THREAT WILL BE ASSOCIATED WITH THE DISCRETE SUPERCELLS
THAT CAN DEVELOP IN THE WARM SECTOR AND POSSIBLY EMBEDDED IN THE
MORE LINER ACTIVITY VICINITY COLD FRONT.  ADDITIONALLY WIND DAMAGE
WILL EXIST WITH SAME ACTIVITY GIVEN THE INTENSITY OF THE WIND FIELDS
ALOFT.

THIS THREAT OF ISOLATED TORNADOES/WIND DAMAGE WILL CONTINUE NEWD
OVERNIGHT THRU THE MID ATLANTIC STATES AS THE SYSTEM SURFACE AND
ALOFT INTENSIFIES FURTHER.

..HALES.. 01/07/2007