DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 230103
SWODY1
SPC AC 230100

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0800 PM CDT SAT SEP 22 2007

VALID 230100Z - 231200Z

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS ECNTRL AZ...

..AZ AND SE UT...
AN UPPER-LEVEL LOW OVER CNTRL CA IS EVIDENT ON WATER VAPOR WITH A
WELL-DEFINED DRY SLOT LOCATED ACROSS THE NRN SECTION OF BAJA CA
EXTENDING NNEWD INTO SW AZ. SCATTERED THUNDERSTORMS ARE ONGOING
ALONG THE LEADING EDGE OF THE DRY SLOT IN A PLUME OF MID-LEVEL
MOISTURE ACROSS CNTRL AZ NWD INTO ERN UT WHERE PRECIPITABLE WATER
VALUES GENERALLY RANGE FROM 1 TO 1.5 INCHES. THE GREATEST
THUNDERSTORM COVERAGE SHOULD GRADUALLY DRIFT EWD INTO FAR SE UT AND
FAR ERN AZ AS THE DRY SLOT ADVANCES EWD AND THE UPPER-LEVEL LOW
DRIFTS SLOWLY TOWARD THE REGION.

CONCERNING THE SEVERE POTENTIAL...A BROAD 80 KT MID-LEVEL JET
EVIDENT ON RUC ANALYSIS IS CENTERED OVER SRN NV AND THIS FEATURE IS
CREATING STRONG VERTICAL SHEAR PROFILES FROM CNTRL AZ NWD INTO SRN
UT. THIS ALONG WITH SBCAPE VALUES AROUND 1000 J/KG FROM CNTRL TO NRN
AZ AND STEEP MID-LEVEL LAPSE RATES SHOULD SUPPORT A THREAT FOR
ROTATING STORMS CAPABLE OF PRODUCING LARGE HAIL. THE GREATEST
POTENTIAL FOR LARGE HAIL SHOULD BE EAST OF INTERSTATE 17 IN ECNTRL
AZ WHERE MID-LEVEL LAPSE RATES ARE LOCALLY VERY STEEP AND
INSTABILITY IS MAXIMIZED. ISOLATED WIND DAMAGE WILL ALSO BE POSSIBLE
WITH THE GREATEST POTENTIAL EAST OF THE PHOENIX AREA WHERE LOW-LEVEL
LAPSE RATES ARE LOCALLY VERY STEEP. THE SEVERE THREAT SHOULD
GRADUALLY DIMINISH THIS EVENING AS INSTABILITY DECREASES ACROSS THE
REGION.

..SRN FL...
A CLUSTER OF STRONG THUNDERSTORMS IS ONGOING IN SRN FL EXTENDING
NWWD TO NEAR TAMPA BAY. THE ACTIVITY IS LOCATED IN A STRONGLY
UNSTABLE ENVIRONMENT EVIDENT ON THE 00Z MIAMI SOUNDING WITH MUCAPE
VALUES LOCALLY EXCEEDING 3000 J/KG. EVEN THOUGH WEAK SHEAR PROFILES
ARE IN PLACE...THE STRONG INSTABILITY AND SFC DEWPOINTS IN THE MID
70S F MAY SUPPORT AN ISOLATED WIND DAMAGE THREAT FOR ANOTHER HOUR
ACROSS SRN FL.

.BROYLES.. 09/23/2007

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