SPC AC 011229
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0729 AM CDT TUE JUN 01 2010
VALID 011300Z - 021200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CENTRAL PLAINS INTO
THE MID/UPPER MS VALLEY...
...UPPER MS VALLEY INTO WESTERN GREAT LAKES...
RELATIVELY FAST ZONAL FLOW IS PRESENT TODAY ACROSS THE
CENTRAL/NORTHERN UNITED STATES...WITH SEVERAL EMBEDDED LOW-AMPLITUDE
SHORTWAVE TROUGHS. ONE STRONG SYSTEM IS NOTED ON WATER VAPOR
IMAGERY OVER MANITOBA/NORTHWEST ONTARIO WITH 12Z RAOBS/MODELS
SHOWING AN ASSOCIATED 50-70 KNOT WESTERLY MID LEVEL JET ALONG THE
US/CANADIAN BORDER. THE RIGHT-ENTRANCE REGION OF THIS JET WILL MOVE
ACROSS THE UPPER MS VALLEY TODAY...WHILE ANOTHER MORE SUBTLE
SHORTWAVE TROUGH APPROACHES THE REGION FROM THE WEST. THESE
FEATURES WILL INCREASE LARGE SCALE FORCING FOR UPWARD MOTION AND
LEAD TO MULTIPLE BANDS/CLUSTERS OF INTENSE THUNDERSTORMS THIS
AFTERNOON AND EVENING ACROSS PARTS OF MN/IA/NEB/KS/MO.
STORMS ONGOING OVER SOUTHERN NEB MAY WEAKEN THIS LATER MORNING
BEFORE RE-INTENSIFYING WITH THE HEAT OF THE DAY ACROSS IA/MO AS
MLCAPE VALUES EXCEED 2000 J/KG. OTHER STORMS ARE EXPECTED TO
INITIATE ALONG THE SURFACE COLD FRONT OVER SOUTHEAST SD/SOUTHERN MN
AND SPREAD SOUTHEASTWARD INTO IA/WI. BOTH OF THESE AREAS WILL
LIKELY SEE SUPERCELL STORM STRUCTURES CAPABLE OF VERY LARGE HAIL AND
ISOLATED TORNADOES. AN EVENTUAL TREND OF UPSCALE ORGANIZATION INTO
A FAST-MOVING MCS IS POSSIBLE TONIGHT AS STORMS SPREAD ACROSS IL
INTO IND...WITH DAMAGING WINDS BECOMING MORE LIKELY.
...KS/NEB...
ANOTHER FAST-MOVING SHORTWAVE TROUGH CURRENTLY OVER UT WILL CROSS
THE CENTRAL ROCKIES AND BEGIN AFFECTING THE HIGH PLAINS BY LATE
AFTERNOON AND EARLY EVENING. EASTERLY/NORTHEASTERLY LOW LEVEL WINDS
ALONG AND NORTH OF THE SURFACE BOUNDARY OVER NORTHERN KS WILL
TRANSPORT RICH LOW LEVEL MOISTURE WESTWARD WITH DEWPOINTS IN THE MID
60S OVER MUCH OF SOUTHERN NEB. ISOLATED THUNDERSTORM DEVELOPMENT IS
EXPECTED ALONG THE OLD FRONT FROM THE NEB PANHANDLE INTO SOUTHEAST
NEB. THOSE STORMS THAT FORM WILL LIKELY BE SUPERCELLS WITH THE RISK
OF LARGE HAIL...DAMAGING WINDS...AND ISOLATED TORNADOES.
...NORTHEAST AND MID ATLANTIC STATES...
MORNING SURFACE ANALYSIS SHOWS A COLD FRONT MOVING EASTWARD ACROSS
PA/NY. SCATTERED THUNDERSTORMS ARE EXPECTED TO FORM ALONG/AHEAD OF
THE FRONT AND SPREAD EASTWARD ACROSS SOUTHERN NEW ENGLAND THROUGH
THE AFTERNOON. MORE ISOLATED STORMS WILL ALSO BE POSSIBLE FARTHER
SOUTH INTO THE MID ATLANTIC STATES THROUGH THE LATE AFTERNOON. DEEP
LAYER VERTICAL SHEAR SUGGESTS A FEW STORMS MAY BECOME ORGANIZED WITH
THE RISK OF LOCALLY DAMAGING WINDS AND HAIL. AREAL COVERAGE OF
SEVERE STORMS IS CURRENTLY EXPECTED TO BE RATHER SPARSE...THUS HAVE
MAINTAINED ONLY LOW SEVERE PROBABILITIES.
..HART/GRAMS.. 06/01/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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