SPC AC 270556
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1256 AM CDT MON JUL 27 2009
VALID 281200Z - 291200Z
...NO SVR TSTM AREAS FORECAST...
...SRN PLAINS/OZARKS...
AN UPPER-LEVEL TROUGH IS FORECAST TO DIG SSEWD ACROSS THE CNTRL
PLAINS INTO THE SRN PLAINS TUESDAY. SCATTERED THUNDERSTORMS APPEAR
LIKELY TO BE ONGOING IN THE MORNING ALONG A COLD FRONT IN THE CNTRL
PLAINS. SOME OF THIS CONVECTION COULD PERSIST INTO THE AFTERNOON AS
THE FRONT MOVES SWD INTO THE SRN PLAINS. ALTHOUGH THE MODELS TIMING
OF THE FRONT SWD IS SLIGHTLY DIFFERENT...THERE IS AGREEMENT WITH
DEVELOPING MODERATE INSTABILITY SOUTH OF THE BOUNDARY FROM NE NM
NEWD ACROSS THE TX PANHANDLE...OK..SE KS AND SRN MO AS SFC TEMPS
HEAT UP AROUND MIDDAY. SCATTERED THUNDERSTORMS SHOULD INITIATE ALONG
THE BOUNDARY AS A CAP WEAKENS AND THE AIRMASS DESTABILIZES. FORECAST
SOUNDINGS ALONG THE BOUNDARY SUGGEST VERTICAL SHEAR PROFILES WILL BE
SUFFICIENT FOR ISOLATED SEVERE STORMS MAINLY DUE TO A STEADY
INCREASE IN WIND SPEEDS IN THE 700 MB TO 300 MB LAYER. LOW-LEVEL
LAPSE RATES SHOULD BECOME VERY STEEP IN THE AFTERNOON WHICH COMBINED
WITH SFC DEWPOINTS IN THE 60S F WITH MODERATE INSTABILITY MAY RESULT
IN A POTENTIAL FOR WET MICROBURSTS WITH THE MORE PERSISTENT STORM
CLUSTERS. THE LACK OF A LOW-LEVEL JET SHOULD HINDER MCS DEVELOPMENT
AND FOR THIS REASON...SEVERE STORMS COVERAGE IS NOT EXPECTED TO BE
THAT GREAT.
...MID-MS VALLEY/NRN OH VALLEY/SRN LOWER MI...
A SHORTWAVE TROUGH WITH A FAIRLY WELL-DEFINED MID-LEVEL JET IS
FORECAST TO MOVE INTO THE WRN GREAT LAKES TUESDAY. AT THE SFC...A
COLD FRONT WILL ADVANCE SEWD ACROSS THE UPPER MS VALLEY. MODELS
FORECAST AN AXIS OF INSTABILITY WELL AHEAD OF THE BOUNDARY FROM ERN
MO AND IL NEWD INTO IND AND SRN LOWER MI. SCATTERED THUNDERSTORMS
APPEAR LIKELY TO DEVELOP ALONG THE WRN EDGE OF THE INSTABILITY AXIS
TUESDAY AFTERNOON. DUE TO INFLUENCE FROM THE MID-LEVEL
JET...ADEQUATE VERTICAL SHEAR SHOULD EXIST ACROSS THE REGION FOR A
MARGINAL SEVERE THREAT. THE SWRN END OF A LOW-LEVEL JET SHOULD BE IN
PLACE FROM NERN IL NEWD INTO SRN LOWER MI WHICH MAY AID THE THREAT
FOR ISOLATED DAMAGING WIND GUSTS AS LOW-LEVEL RATES BECOME QUITE
STEEP IN THE LATE AFTERNOON.
..BROYLES.. 07/27/2009
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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