Severe Thunderstorm Warning 14, NWS Tucson, AZ

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
230 PM MST THU JUL 12 2001

SYNOPSIS...HIGH PRESSURE TO OUR EAST WILL CONTINUE TO PROVIDE A
MOIST SOUTHERLY FLOW WITH ISOLATED TO SCATTERED AFTERNOON AND
EVENING THUNDERSTORMS ACROSS THE AREA. A GRADUAL DRYING TREND WILL
BEGIN OVER THE WEEKEND GENERALLY WEST OF TUCSON AS A TROUGH DIGS
INTO THE WEST COAST DURING THE UPCOMING WEEKEND.

DISCUSSION...PRECIPITABLE WATER WAS UP ON THE KTUS MORNING
SOUNDING...BUT WE'VE ALSO WARMED A LITTLE AT MID LEVELS. MINOR
DISTURBANCES WITH WEAK PVA EMBEDDED IN MOIST SOUTHERLY FLOW...BUT
HARD TO PICK OUT. NICE MOISTURE AND ENERGY BUT WIND PROFILE NOT THE
BEST. SOUNDS LIKE A BROKEN RECORD...BUT NOTHING REALLY TO SAY ANY
DIFFERENT THAN SCATTERED THUNDERSTORMS GETTING STARTED IN THE
MOUNTAINS THIS AFTERNOON WITH SOME ABLE TO PROPAGATE INTO VALLEY
LOCATIONS MID TO LATE AFTERNOON AND/OR EARLY EVENING. SHOULD SEE A
FEW SPOTS OF LOCALLY HEAVY RAINFALL...MAINLY MOUNTAINS. LINGERING
ISOLATED CONVECTION EMBEDDED IN MOIST SOUTHERLY FLOW WILL LIKELY
KEEP THE RADAR FROM GOING COMPLETELY PPINE OVERNIGHT.

LOW NEAR CENTRAL BAJA GETS DRAWN INTO THE FLOW...LIKELY IN
PIECES...EARLY THIS WEEKEND AS THE TROUGH DEVELOPS NEAR THE WEST
COAST. WE COULD SEE SOME ENHANCEMENT OR FOCUS FROM THIS FRIDAY
AND/OR SATURDAY. AFTER THIS WE SHOULD SEE THE DEEP MOISTURE BOUNDARY
FORCED GRADUALLY EASTWARD WITH WESTERN ZONES DRYING OUT. STILL
SHOULD BE ABLE TO HOLD ON TO SOME THUNDERSTORMS FROM TUCSON EAST AND
SOUTH.

.TWC...NONE.

AZZ019-029>035-130700-

SOUTHEAST ARIZONA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1200 PM MST THU JUL 12 2001

.SYNOPSIS...THE COMBINATION OF SURFACE HEATING AND AMPLE MOISTURE
ACROSS THE REGION WILL RESULT IN THUNDERSTORM DEVELOPMENT OVER THE
HIGHER TERRAIN THIS AFTERNOON...WITH ONLY A HANDFUL OF THESE STORMS
PUSHING OFF INTO THE VALLEYS LATE THIS AFTERNOON AND EVENING. THE
RISK OF SEVERE STORMS AND FLASH FLOODING WILL BELOW CLIMATOLOGY
TODAY ACROSS MOST OF THE REGION WITH THE GREATEST THREAT OF SEVERE
STORMS WEST OF TUCSON...AND THE GREATEST THREAT OF FLASH FLOODING
OVER THE MOUNTAINS.

.DISCUSSION...A WEAK DISTURBANCE EXTENDING NORTH-SOUTH ACROSS
WESTERN ARIZONA WILL SLIGHTLY AID THUNDERSTORM DEVELOPMENT...MAINLY
WEST OF TUCSON THIS AFTERNOON. ELSEWHERE...AN AREA OF SUBSIDENCE
OVER NORTHERN SONORA WILL NOSE ITS WAY NORTH INTO THE SOUTHEASTERN
ARIZONA...SUPPRESSING ANY SIGNIFICANT STORM DEVELOPMENT.

OTHERWISE...WITH PLENTY OF SURFACE HEATING AND AMPLE MOISTURE ACROSS
THE REGION...LOOK FOR THUNDERSTORMS TO DEVELOP OVER THE HIGHER
TERRAIN EARLY THIS AFTERNOON. THE MID LEVEL STEERING FLOW IS STRONG
ENOUGH TO PUSH THUNDERSTORMS OFF OF THE MOUNTAINS. HOWEVER..JUST
LIKE YESTERDAY...THE MAJOR PROBLEM WILL BE THE FACT THAT A STRONG
FLOW ALOFT WILL NOT ONLY PUSH THE ANVILS AHEAD OF THE STORMS BUT
STRONG SHEAR WITH HEIGHT WILL NOT ALLOW DEEP CONVECTION TO OCCUR.
THEREFORE...ONLY A HANDFUL OF THESE STORMS ARE EXPECTED TO PUSH OFF
OF THE MOUNTAINS AND ORGANIZE OVER THE VALLEYS BY LATE THIS
AFTERNOON. THE THREAT OF SEVERE STORMS WILL BE BELOW CLIMATOLOGY
TODAY ACROSS MOST OF SOUTHEAST ARIZONA...WITH VALUES CLOSER TO
CLIMATOLOGY WEST OF TUCSON.

STORM MOTION WILL BE TOWARDS THE NORTH AT 15 MPH.

THE FASTER STORM MOTIONS BY THE STORMS THAT MANAGE TO PUSH OFF THE
MOUNTAINS TODAY WILL REDUCE THE THREAT OF FLASH FLOODING ACROSS
VALLEY LOCATIONS. HOWEVER...SINCE THUNDERSTORMS WILL MAINLY BE
CONFINED TO THE HIGHER TERRAIN...A GREATER THREAT OF FLASH
FLOODING...APPROACHING CLIMATOLOGY...WILL BE ASSESSED TO THE
MOUNTAINS.