Damaging Wind in Arizona, August 18, 2002

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
210 PM MST SUN AUG 18 2002

.SYNOPSIS...HIGH PRESSURE OVER NORTHERN ARIZONA WILL MOVE EAST AS
LOW PRESSURE ALOFT DEVELOPS ALONG THE WEST COAST THE NEXT FEW DAYS.
THIS PATTERN WILL PROVIDE SOUTHERLY FLOW AND AN INCREASE IN MOISTURE
FOR SOUTHEAST ARIZONA. LOOK FOR AN INCREASE IN THUNDERSTORM ACTIVITY
THIS WEEK.

.DISCUSSION...CONVECTION HAS EVOLVED AS EXPECTED SO FAR THIS
AFTERNOON. INITIAL DEVELOPMENT HAS BEEN RAPID AND STRONG OVER THE
MOUNTAINS. A VERY WEAK SHEAR PROFILE ALONG WITH A NEARLY
NON-EXISTENT STEERING FLOW HAS SEEN THEM DIE IN PLACE WITH LITTLE
INCLINATION TO PUSH INTO VALLEY LOCATIONS THUS FAR. WE MAY BE ABLE
TO GET LUCKY WITH OUTFLOW IN SOME SPOTS...BUT NOT AS A WIDESPREAD
TREND. MOISTURE TRENDS ARE ON THE INCREASE ACROSS THE AREA WITH AN
EBB FROM THE SOUTH. GOES SOUNDER PW ESTIMATES IN THE 1.2 TO 1.3 INCH
RANGE...AND SURFACE DEWPTS HOLDING IN THE 55 TO 60 RANGE (ABOUT 5
DEGREES BETTER THAN YESTERDAY). SO...ITS NOT OVER YET FOR THIS
AFTERNOON AND EVENING.

NICE COMPLEX ORGANIZING IN NORTHWEST MEXICO UNDER THE INFLUENCE OF
WEAKNESS IN FLOW. MAKING A PUSH IN OUR DIRECTION...COULD INFLUENCE
STORM DEVELOPMENT FROM THE SOUTH IN THE EVENING HOURS. AS THE HIGH
REFORMS TO OUR EAST AND THE SOUTHERLY FLOW INCREASES...WELL GET THE
DEEPER MOISTURE AND A MUCH MORE FAVORABLE PROFILE FOR CONVECTION BY
LATE MONDAY AND TUESDAY OVER THE AREA WITH AN EASTERLY WAVE ROTATING
THROUGH AROUND THE HIGH. AFTER THAT...STANDARD SEASONAL THUNDERSTORM
FORECAST WITH DRY WESTERLY COMPONENT TRYING TO PUSH INTO FAR WESTERN
AND NORTHERN AREAS FROM A DEVELOPING WEST COAST TROUGH. MOST OF OUR
AREA SHOULD MAINTAIN A MOIST THUNDERSTORM FLOW. M

TWC...NONE.

AZZ019-029>035-190700-

SOUTHEAST ARIZONA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1145 AM MST SUN AUG 18 2002

.SYNOPSIS...A TYPICAL DAY WITH SUFFICIENT MOISTURE AND INSTABILITY
FOR CONVECTION TO DEVELOP OVER HIGHER TERRAIN. SOME STORMS WILL MOVE
INTO VALLEY LOCATIONS...BUT A WEAK SHEAR PROFILE AND SLOW STORM
MOVEMENT MAY INHIBIT THIS PROCESS. EXPECT THE CHANCES OF SEVERE
STORMS AND 1 INCH OR GREATER RAINFALL TO BOTH BE SUPERIOR TO
SATURDAY AND NEAR CLIMATOLOGY.

.DISCUSSION...12Z KTUS SOUNDING MOISTURE PROFILE PROBABLY A LITTLE
HOKEY AS PER THE MORNING AFD. EVEN SO...THE MOISTURE TREND WILL
INDEED BE UP OVER THE NEXT 24 TO 48 HRS AS MOISTURE SEEPS IN FROM
THE SOUTH. SOME SURGE SIGNATURE CONTINUES AT YUMA...BUT NOT
GANGBUSTERS. DECENT STORMS WILL HAVE NO PROBLEM FORMING OVER THE
MOUNTAINS AS USUAL. A LESS-THAN-FAVORABLE SHEAR PROFILE AND STEERING
FLOW MAY SHORTEN THE LIFE OF STORMS WHILE ALSO KEEPING THEM CLOSER
TO HIGHER TERRAIN IN GENERAL...ESPECIALLY EARLY IN THE AFTERNOON.

INDIVIDUAL CELL MOVEMENT WILL BE TO THE WEST OR NORTHWEST AT 5 TO 8
MPH.

AZZ019-029>035-190700-

SOUTHEAST ARIZONA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1145 AM MST SUN AUG 18 2002

.SYNOPSIS...A TYPICAL DAY WITH SUFFICIENT MOISTURE AND INSTABILITY
FOR CONVECTION TO DEVELOP OVER HIGHER TERRAIN. SOME STORMS WILL MOVE
INTO VALLEY LOCATIONS...BUT A WEAK SHEAR PROFILE AND SLOW STORM
MOVEMENT MAY INHIBIT THIS PROCESS. EXPECT THE CHANCES OF SEVERE
STORMS AND 1 INCH OR GREATER RAINFALL TO BOTH BE SUPERIOR TO
SATURDAY AND NEAR CLIMATOLOGY.

.DISCUSSION...12Z KTUS SOUNDING MOISTURE PROFILE PROBABLY A LITTLE
HOKEY AS PER THE MORNING AFD. EVEN SO...THE MOISTURE TREND WILL
INDEED BE UP OVER THE NEXT 24 TO 48 HRS AS MOISTURE SEEPS IN FROM
THE SOUTH. SOME SURGE SIGNATURE CONTINUES AT YUMA...BUT NOT
GANGBUSTERS. DECENT STORMS WILL HAVE NO PROBLEM FORMING OVER THE
MOUNTAINS AS USUAL. A LESS-THAN-FAVORABLE SHEAR PROFILE AND STEERING
FLOW MAY SHORTEN THE LIFE OF STORMS WHILE ALSO KEEPING THEM CLOSER
TO HIGHER TERRAIN IN GENERAL...ESPECIALLY EARLY IN THE AFTERNOON.

INDIVIDUAL CELL MOVEMENT WILL BE TO THE WEST OR NORTHWEST AT 5 TO 8
MPH.