SPC AC 101215
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0615 AM CST THU JAN 10 2008
VALID 101300Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE LOWER MS
VALLEY...CENTRAL GULF COAST STATES...AND TN VALLEY...
...LOWER MS VALLEY/CENTRAL GULF COAST...
MORNING WATER VAPOR LOOPS SHOW STRONG UPPER TROUGH OVER THE CENTRAL
PLAINS. THIS FEATURE IS FORECAST TO MOVE EASTWARD TODAY...WITH
ASSOCIATED 90-100 KNOT MID LEVEL JET SPREADING ACROSS PARTS OF
AR/MO/IL. SURFACE LOW NOW OVER EASTERN KS IS 2-3MB DEEPER THAN
PROGD BY NAM...AND SHOULD CONTINUE TO DEEPEN AS IT MOVES INTO THE
MID MS VALLEY. STRONG SOUTHERLY LOW LEVEL WINDS ARE ALSO EXPECTED
TO INTENSIFY OVER THE CENTRAL GULF COAST AND TN VALLEY TODAY...
HELPING TO TRANSPORT GULF MOISTURE NORTHWARD. ALL OF THESE FACTORS
WILL RESULT IN AN INCREASING RISK OF SEVERE STORMS OVER THE REGION
TODAY.
SCATTERED THUNDERSTORMS ARE INCREASING IN COVERAGE THIS MORNING
ALONG LOW LEVEL JET AXIS FROM NORTHWEST LA INTO WESTERN TN. THIS
ACTIVITY IS ELEVATED ABOVE STABLE BOUNDARY LAYER AND IN REGION OF
ONLY MARGINAL INSTABILITY. NEVERTHELESS...STRONGER CORES COULD
PRODUCE HAIL THROUGH THE MORNING HOURS.
THIS ACTIVITY...ALONG WITH NEW THUNDERSTORM DEVELOP ACROSS PARTS OF
LA/MS...WILL LIKELY BECOME SURFACE-BASED BY LATE MORNING AS LOW
LEVEL MOISTURE STREAMS NORTHWARD. AS THIS OCCURS...STORMS WILL
BEGIN TO INGEST FAVORABLE LOW LEVEL VERTICAL SHEAR PROFILES
INDICATED ON MODEL SOUNDINGS ACROSS REGION /3KM HELICITY OF 250-350
M2/S2/. PRESENT INDICATIONS ARE THAT THESE STORMS WILL LIKELY
INCLUDE SCATTERED SUPERCELLS CAPABLE OF TORNADOES AND DAMAGING
WINDS. MODEL GUIDANCE SUGGESTS THAT EXTENSIVE LOW CLOUDS WILL LIMIT
DAYTIME HEATING AND DESTABILIZATION. HOWEVER...IF BREAKS IN THE
CLOUDS CAN DEVELOP...AN UPGRADE TO MODERATE RISK COULD BE REQUIRED
DUE TO STRONG NATURE OF THE SHEAR PROFILES. ACTIVITY IS EXPECTED TO
CONTINUE TO INCREASE IN ORGANIZATION AND INTENSITY AS STORMS TRACK
EASTWARD ACROSS MS INTO AL AND FL PANHANDLE DURING THE
EVENING/NIGHT.
...TN/KY...
NORTHWARD EXTENT OF SEVERE THREAT IS MUCH LESS CERTAIN THAN FARTHER
SOUTH. MORNING SURFACE ANALYSIS SHOWS APPARENT WARM FRONT EXTENDING
ACROSS TN. THIS BOUNDARY WILL RETREAT NORTHWARD INTO KY TODAY...BUT
DEGREE OF MOISTENING/DESTABILIZATION THAT FAR NORTH IS UNCLEAR.
GIVEN STRENGTH OF LOW LEVEL WIND FIELDS /50-65 KNOT WINDS AT 850MB
AND 3KM HELICITY OF 300+ MS/S2/...POTENTIAL WILL EXIST FOR DAMAGING
WINDS AND ISOLATED TORNADOES IN ANY SURFACE-BASED THUNDERSTORMS THAT
BECOME ORGANIZED.
..HART.. 01/10/2008
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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