SPC AC 181615
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1115 AM CDT FRI MAY 18 2007
VALID 181630Z - 191200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ND AND MN...
...ND/MN...
LARGE UPPER RIDGE IS IN PLACE THIS MORNING OVER MUCH OF THE CENTRAL
UNITED STATES...WITH SEVERAL WEAK UPPER FEATURES ROTATING ATOP
TROUGH FROM THE NORTHERN ROCKIES INTO THE PRAIRIE PROVINCES OF
CANADA...THEN SOUTHEASTWARD INTO THE GREAT LAKES. WATER VAPOR
IMAGERY HINTS AT ONE SHORTWAVE TROUGH MOVING ACROSS NORTH CENTRAL
MT. THIS SYSTEM IS EXPECTED TO TRACK INTO ND THROUGH THE
AFTERNOON...AND ACROSS MN TONIGHT. LATEST SURFACE ANALYSIS SHOWS
WEAK COLD FRONT EXTENDING ALONG THE MANITOBA/ND BORDER. ANOTHER
WEAK BOUNDARY EXTENDS FROM THE MOT AREA SOUTHWESTWARD TO WEST OF
DIK. STRONG HEATING ALONG AND SOUTHEAST OF THESE
BOUNDARIES...COUPLED WITH DEWPOINTS IN THE 50S...WILL RESULT IN
MLCAPE VALUES AROUND 2000 J/KG AND MINIMAL CAP. FORECAST SOUNDINGS
SHOW STEEP LOW/MID LEVEL LAPSE RATES AND SUFFICIENT DEEP LAYER
VERTICAL SHEAR FOR ORGANIZED MULTICELL OR SUPERCELL STORMS. LARGE
HAIL AND DAMAGING WINDS APPEAR POSSIBLE IN STRONGER CORES AS
ACTIVITY MOVES FROM ND INTO MN DURING THE EVENING.
...MT...
SHORTWAVE RIDGING IS OCCURRING THIS MORNING OVER CENTRAL/WESTERN MT.
THIS IS RESULTING IN CLEAR SKIES AND STRONG DIURNAL HEATING OVER
THE MOUNTAINS OF SOUTHWEST AND SOUTH CENTRAL MT. RELATIVELY COOL
TEMPERATURES ALOFT WILL PROVIDE STEEP MID LEVEL LAPSE RATES AND
PROMOTE SCATTERED THUNDERSTORMS THIS AFTERNOON OVER THE HIGHER
TERRAIN. FORECAST SOUNDINGS APPEAR FAVORABLE FOR HAIL IN STRONGER
CELLS...WHILE STEEP LOW LEVEL LAPSE RATES AID POTENTIAL FOR GUSTY
WINDS. STORMS MAY BE HARD PRESSED TO MOVE OFF THE MOUNTAINS DUE TO
UPPER RIDGING ACROSS THE AREA.
...FL...
WEAK SURFACE COLD FRONT IS SAGGING SOUTHWARD ACROSS THE NORTHERN FL
PENINSULA TODAY. FULL SUNSHINE IS OCCURRING ALONG AND SOUTH OF
FRONT...WHERE SURFACE DEWPOINTS REMAIN IN THE MID 60S. A MODERATELY
UNSTABLE AIR MASS IS FORECAST TO DEVELOP BY EARLY AFTERNOON WITH
MLCAPE VALUES OVER 1000 J/KG. DEEP /ALBEIT WEAK/ WESTERLY FLOW
ALOFT WILL ENHANCE CONVERGENCE ALONG THE EAST-COAST SEA
BREEZE...WHERE INITIAL THUNDERSTORM DEVELOPMENT IS EXPECTED. STORMS
ARE LIKELY TO PROPAGATE SOUTHWARD ALONG SEA BREEZE/COLD FRONT
INTERSECTION THROUGH THE EARLY EVENING. MULTICELL STORMS CAPABLE OF
GUSTY WINDS AND HAIL APPEAR POSSIBLE.
...SRN NM/SW TX...
LOW CLOUDS ARE LIKELY TO REMAIN OVER THE PLAINS OF EASTERN NM AND
WEST TX INTO THIS AFTERNOON...LIMITING INSTABILITY IN THIS AREA.
HOWEVER...HEATING/DESTABILIZATION IS OCCURRING FROM THE ELP AREA
NORTHWARD TOWARD RUI. CONSIDERABLE LOW LEVEL MOISTURE IS IN PLACE
ALONG THIS CORRIDOR WITH DEWPOINTS IN THE 50S. SCATTERED
THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS REGION THIS AFTERNOON.
LOW LEVEL EASTERLY WINDS COUPLED WITH 15-25 KNOT WESTERLY WINDS
ALOFT MAY BE SUFFICIENT FOR ISOLATED STRONG STORMS CAPABLE OF GUSTY
WINDS AND HAIL. ORGANIZED SEVERE STORMS ARE NOT EXPECTED IN THIS
REGION TODAY.
..HART/JEWELL.. 05/18/2007
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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