Saturday, July 7, 2007

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 071954
SWODY1
SPC AC 071952

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0252 PM CDT SAT JUL 07 2007

VALID 072000Z - 081200Z

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS ND EWD INTO NRN MN/NRN
WI AND WRN UPPER MI...

..THERE IS A SLGT RISK OF SVR TSTMS FROM FAR SERN MS EWD INTO SWRN
GA...

..ERN ND/NRN MN...
THOUGH DIFFICULT TO DISCERN IN SATELLITE IMAGERY...MODELS ARE
SIMILAR IN SHOWING A SHORTWAVE TROUGH SPREADING EWD FROM WRN ND INTO
MN THIS EVENING. A SURFACE LOW WAS LOCATED NEAR THE ND/MANITOBA
BORDER...WITH A COLD FRONT EXTENDING NE-SW THROUGH THE LOW...AND A
TROUGH STRETCHING SWD ACROSS CENTRAL ND. MID AFTERNOON DIAGNOSTIC
FIELDS SHOW THE ENVIRONMENT EAST OF SURFACE TROUGH/FRONT IS STILL
STRONGLY CAPPED. HOWEVER...ADDITIONAL SURFACE WARMING AND LARGE
SCALE LIFT ASSOCIATED WITH UPPER TROUGH SHOULD AID STORM
FORMATION...MAINLY NEAR SURFACE LOW AND PRE-MENTIONED SURFACE
FEATURES...IN FAR ERN ND/NWRN MN TOWARD 00Z. ONCE STORMS
DEVELOP...MODERATE TO STRONG INSTABILITY AND EFFECTIVE BULK SHEAR IN
EXCESS OF 40 KT WILL SUPPORT SUPERCELLS. LARGE HAIL AND A TORNADO OR
TWO WILL BE POSSIBLE WITH THE INITIAL SUPERCELLS. AS OUTFLOWS
CONGEAL DURING THE EVENING ...CONVECTION MAY EVOLVE INTO A SMALL BOW
ECHO...WITH AN INCREASING THREAT FOR DAMAGING WINDS ACROSS NRN MN.
THESE STORMS WILL LIKELY PERSIST INTO THE OVERNIGHT HOURS...POSSIBLY
REACHING NRN WI AND WRN UPPER MI BEFORE WEAKENING.

..COASTAL MS/SRN AL/SWRN GA AND THE WRN FL PANHANDLE...
A MID LEVEL SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW WERE LOCATED
OVER CENTRAL MS AND MOVING SLOWLY EWD. AT MID AFTERNOON...
CONVECTION ASSOCIATED WITH THIS SYSTEM EXTENDED FROM WEST CENTRAL AL
SWWD INTO FAR SERN MS...ALONG A CONVERGENT SURFACE TROUGH. A VERY
MOIST AIR MASS WAS PRESENT AHEAD OF THIS CONVECTION ALONG WITH A A
NARROW BAND OF 30 KT LOW-MID LEVEL WINDS. SUFFICIENT DEEP LAYER
SHEAR IS PRESENT FOR A FEW ROTATING STORMS. GIVEN THE DEEP MOIST
BOUNDARY LAYER AND 20-25 KT 1KM SHEAR...A BRIEF TORNADO OR TWO AND
ISOLATED DAMAGING GUSTS WILL BE POSSIBLE THOUGH THE AFTERNOON HOURS.


..CENTRAL ID/SRN MT/WRN WY THIS AFTERNOON...
SHORTWAVE TROUGH OVER ID WILL ROTATE NEWD AROUND UPPER HIGH INTO
SWRN MT/NWRN WY THIS EVENING. STRONG HEATING COMBINED WITH MOIST MID
LEVELS AND LARGE SCALE LIFTING HAD RESULTED IN THUNDERSTORMS TO
DEVELOP OVER THE HIGHER TERRAIN. THESE STORMS SHOULD INTENSIFY AND
INCREASE IN NUMBER AS THE AIR MASS DESTABILIZES FURTHER WITH
ADDITIONAL HEATING. THE DEEPLY MIXED LAYER/INVERTED-V PROFILES
SHOULD SUPPORT A FEW STORMS WITH STRONG/DAMAGING DOWNBURST WINDS
INTO THE EARLY EVENING HOURS.

..WRN NM/SERN AZ...
CIRCULATION AROUND HIGH PRESSURE CENTER IN EXTREME SRN NV IS
RESULTING IN PERSISTENT 30-35 KT MID LEVEL NNELY FLOW ACROSS THE
REGION. A WEAK SHORTWAVE TROUGH MIGRATING SWWD THROUGH NWRN NM PLUS
MID LEVEL MOISTURE HAD AIDED STORM FORMATION OVER THE HIGH TERRAIN
OF WRN NM. AS THESE STORMS MOVE SSWWD INTO THE LOWER
ELEVATIONS...THE VERY HOT TEMPERATURES/WELL MIXED BOUNDARY LAYER
WILL BE FAVORABLE FOR STRONG WIND GUSTS.

.IMY.. 07/07/2007

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