SPC AC 190444
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1144 PM CDT FRI SEP 18 2009
VALID 191200Z - 201200Z
...NO SVR TSTM AREAS FORECAST...
...SERN U.S./TN VALLEY...
WEAK WARM ADVECTION REGIME WILL CONTINUE THROUGH THE UPCOMING DAY1
PERIOD AS UPPER TROUGH AXIS REMAINS ANCHORED OVER THE SRN PLAINS.
AHEAD OF THE SRN PLAINS TROUGH A FEW WEAK SHORTWAVES WILL EJECT NEWD
ACROSS THE CNTRL GULF STATES INTO THE TN VALLEY. THESE FEATURES
WILL UNDOUBTEDLY ENHANCE CONVECTIVE THREAT...ESPECIALLY GIVEN THE
HIGH PWAT VALUES AND MODEST INSTABILITY...THOUGH PSEUDO-ADIABATIC
LAPSE RATES WILL PERSIST ACROSS THIS REGION. ALTHOUGH MID LEVEL
FLOW BEGINS TO STRENGTHEN SOME ALONG A CORRIDOR FROM ERN TX INTO WRN
TN/KY LATE...H5 FLOW WILL ONLY BE ON THE ORDER OF 15-20KT. THUS
DESPITE VEERING WIND PROFILES THAT MAY SUPPORT WEAK STORM ROTATION
DEEP LAYER BULK SHEAR WILL BE TOO WEAK TO WARRANT ANY MEANINGFUL
THREAT FOR SEVERE THUNDERSTORMS.
...ROCKIES...
STRONGEST HEATING IN THE CONUS WILL OCCUR ACROSS THE WRN U.S.
SATURDAY. WITH SUFFICIENTLY COOL MID LEVEL TEMPERATURES ACROSS THIS
REGION THERMODYNAMIC PROFILES SHOULD EXHIBIT MORE THAN ADEQUATE
BUOYANCY FOR ANOTHER ROUND OF SCATTERED
SHOWERS/THUNDERSTORMS...ESPECIALLY ACROSS THE SRN/CNTRL ROCKIES.
FARTHER NORTH ACROSS MT...MID LEVEL HEIGHTS WILL BEGIN TO FALL
ACROSS THE NRN ROCKIES LATE AS A RATHER STRONG SHORTWAVE TROUGH
BEGINS TO DIG SEWD INTO BACK SIDE OF BROAD CNTRL U.S. TROUGH.
ALTHOUGH VERTICAL SHEAR WILL INCREASE SUBSTANTIALLY ACROSS THIS
REGION...AHEAD OF SURGING COLD FRONT...AIRMASS ACROSS THIS REGION
SHOULD NOT BE UNSTABLE ENOUGH TO JUSTIFY SEVERE PROBABILITIES.
..DARROW/GRAMS.. 09/19/2009
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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