DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 081945
SWODY1
SPC AC 081942

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0242 PM CDT MON OCT 08 2007

VALID 082000Z - 091200Z

..NO SVR TSTM AREAS FORECAST...

..GREAT LAKES REGION...
AN UPPER-LEVEL LOW OVER THE NRN PLAINS WILL DRIFT NEWD ACROSS NRN MN
AS A COLD FRONT MOVES EWD ACROSS WI AND IL THIS AFTERNOON. SEVERAL
LINES OF THUNDERSTORMS SHOULD DEVELOP ALONG AND AHEAD OF THE FRONT
AS LOW-LEVEL CONVERGENCE AND INSTABILITY INCREASES THIS AFTERNOON.
ALTHOUGH INSTABILITY WILL REMAIN RELATIVELY WEAK...REGIONAL
PROFILERS AND WSR-88D VWPS SUGGEST ENOUGH SHEAR WILL BE IN PLACE FOR
A MARGINAL SEVERE THREAT. OBJECTIVE ANALYSIS CURRENTLY SHOWS 0-3 KM
LAPSE RATES EXCEEDING 7.0 C/KM ALONG THE WRN EDGE OF LAKE MICHIGAN.
LOW-LEVEL LAPSE RATES SHOULD STEEPEN FURTHER OVER THE NEXT FEW HOURS
AND THIS ALONG WITH UNIDIRECTIONAL LOW-LEVEL FLOW MAY BE ENOUGH TO
SUPPORT A MARGINAL WIND DAMAGE THREAT. A HAIL POTENTIAL MAY ALSO
EXIST WITH THE STRONGER CELLS DUE TO COLD AIR ALOFT ASSOCIATED WITH
THE APPROACHING UPPER-LEVEL LOW.

..OZARK PLATEAU...
A LINE OF STRONG THUNDERSTORMS IS CURRENTLY ONGOING FROM SRN MO
EXTENDING SWWD ACROSS NW AR INTO SE OK. THIS ACTIVITY IS LOCATED
ALONG A COLD FRONT AND JUST AHEAD OF A WEAK UPPER-LEVEL TROUGH
EVIDENT ON WATER VAPOR IMAGERY. THE LATEST OBJECTIVE ANALYSIS
SUGGESTS SBCAPE VALUES AHEAD OF THE LINE OF STORMS ARE IN THE 1000
TO 1500 J/KG RANGE. ALTHOUGH VERTICAL SHEAR PROFILES ARE BELOW 25 KT
ACCORDING TO REGIONAL WSR-88D VWPS...THE AMOUNT OF INSTABILITY MAY
BE ENOUGH FOR A MARGINAL WIND DAMAGE OR HAIL THREAT THROUGH LATE
THIS AFTERNOON.

..NY AND SRN NEW ENGLAND...
WATER VAPOR IMAGERY CURRENTLY SHOWS AN UPPER-LEVEL RIDGE LOCATED
ACROSS THE ERN GREAT LAKES REGION. AT THE SFC...A QUASI-STATIONARY
FRONT IS LOCATED FROM NRN NY ESEWD INTO SRN NEW ENGLAND. OBJECTIVE
ANALYSIS SUGGESTS SBCAPE VALUES ALONG AND SOUTH OF THE BOUNDARY
RANGE FROM 1000 TO 2000 J/KG. AS THUNDERSTORMS CONTINUE TO EXPAND IN
COVERAGE THIS AFTERNOON...VERTICAL SHEAR ALONG THE BOUNDARY ITSELF
AND THE AMOUNT OF INSTABILITY PRESENT MAY BE ENOUGH FOR A MARGINAL
SEVERE THREAT. UNDIRECTIONAL BOUNDARY LAYER FLOW AND STEEPENING
LOW-LEVEL LAPSE RATES MAY BE ADEQUATE FOR A MARGINAL WIND DAMAGE
THREAT THIS AFTERNOON WITH THE STRONGER MULTICELL STORMS.

.BROYLES.. 10/08/2007

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