Severe Thunderstorm Warning 41, NWS Tucson, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
145 PM MST FRI AUG 6 2004

SOUTHEAST ARIZONA FORECAST DISCUSSION

.SYNOPSIS...A WEATHER DISTURBANCE SOUTH OF THE INTERNATIONAL BORDER
WILL PROVIDE THE AREA WITH SCATTERED SHOWERS AND THUNDERSTORMS
TONIGHT. HIGH PRESSURE TO OUR EAST WILL MAINTAIN A MOIST SOUTHERLY
FLOW INTO EARLY NEXT WEEK. THIS WILL RESULT IN THE TYPICAL ISOLATED
TO SCATTERED THUNDERSTORMS THE REGION EXPERIENCES THIS TIME OF YEAR
&&

.DISCUSSION...THUNDERSTORM DEVELOPMENT HAS BEEN A LITTLE SLOWER THAN
EXPECTED...BUT A FEW WERE FORMING SOUTH OF OLS AND NEAR PARKER
CANYON LAKE EARLY THIS AFTERNOON. SO FAR THESE STORMS HAVE BEEN
FAIRLY STRONG WITH NOT A LOT OF MOVEMENT OR ORGANIZATION. IF THIS IS
AN INDICATION OF WHAT MAY HAPPEN LATER THIS AFTERNOON AND EVENING...
THE MAIN THREAT WILL BE LOCALLY HEAVY RAINFALL. LATEST GFS MODEL
SUGGESTED THAT THE INVERTED TROUGH TO OUR SOUTH WILL HELP FORM A
COMPLEX OF STORMS LATE THIS EVENING WHICH SHOULD BE FARTHER NORTH
COMPARED TO LAST NIGHT. THIS DEVELOPMENT WOULD TAKE PLACE CLOSER TO
THE INTERNATIONAL BORDER AND KEEP MOST OF SERN AZ UNDER A THREAT OF
THUNDERSTORMS WITH LOCALLY HEAVY DOWNPOURS WELL PAST MIDNIGHT. FOR
NOW...NOT QUITE SURE THERE WILL BE ENOUGH ORGANIZATION TO STORMS
EARLY ON TO WARRANT THE ISSUANCE OF A FLASH FLOOD WATCH.
HOWEVER...THIS WILL BE SOMETHING TO CONSIDER FOR CNTRL COCHISE COUNTY
WESTWARD AS THE EVENING APPROACHES. GIVEN THE SCENARIO THAT A
COMPLEX WILL FORM JUST TO OUR SOUTH AND MOVE OVER PARTS OF SERN AZ
TONIGHT...WILL KEEP POPS UP OVERNIGHT AND INTO EARLY SATURDAY. IF
THIS SCENARIO HAPPENS..THERE SHOULD BE A LATER START IN THE
REDEVELOPMENT OF THUNDERSTORMS SATURDAY ALONG WITH SOMEWHAT LESS
AREAL COVERAGE. AT ANY RATE...MODELS KEEP THE REGION UNDER A MOIST
FLOW WITH THE MID LEVEL HIGH CENTERED SOMEWHERE OVER OR NEAR OUR CWA
THROUGH EARLY NEXT WEEK. EVENTUALLY...GFS MODEL SHIFTS THE HIGH
CENTER NORTH OF US WITH HINT AT BETTER MOISTURE AND UPPER DYNAMICS
AROUND NEXT FRIDAY.
&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1115 AM MST FRI AUG 6 2004

AZZ019-029>035-070700-
NORTHERN GREENLEE COUNTY-UPPER GILA RIVER VALLEY-COCHISE COUNTY-
SOUTHEAST PINAL COUNTY-TUCSON METRO/MARANA/GREEN VALLEY-
SANTA CRUZ COUNTY-TOHONO OODHAM NATION-WESTERN PIMA COUNTY-
1115 AM MST FRI AUG 6 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ARIZONA

.DAY ONE...TODAY

SYNOPSIS...A RATHER ACTIVE AFTERNOON AND EVENING IS EXPECTED OVER
LARGE PORTIONS OF SOUTHEAST ARIZONA. THE RISK OF FLASH FLOODING IS
ABOVE NORMAL...WHILE THE RISK OF DAMAGING DOWNBURST WINDS AND HAIL IS
NEAR NORMAL.

DISCUSSION...THE ATMOSPHERE HAS BECOME QUITE UNSTABLE ACROSS THE
REGION THIS MORNING. CONSIDERABLE MOISTURE HAS SPREAD NORTH FROM A
COUPLE OF THUNDERSTORM COMPLEXES THAT AFFECTED NORTHWEST MEXICO
LAST NIGHT. ISOLATED THUNDERSTORMS MOVED ACROSS COCHISE AND WESTERN
PIMA COUNTIES THIS MORNING...BUT SKIES HAVE SINCE CLEARED.
ELSEWHERE...AFTER PLENTY OF SUNSHINE EARLIER THIS MORNING...CLOUDS
WERE TRYING TO BUILD A LITTLE EARLIER THAN USUAL. IF THAT TREND
CONTINUES...IT MAY CUT INTO DAYTIME HEATING AND KEEP THE ATMOSPHERE
FROM DESTABILIZING TO ITS FULL POTENTIAL. THE MEAN FLOW PATTERN AND
MODEST MID LEVEL SHEAR IS SUFFICIENT TO SUPPORT ORGANIZED
THUNDERSTORM CLUSTERS WHICH MAY NOT ONLY TRAIN...BUT ALSO SUSTAIN
THEMSELVES WELL AFTER SUNSET. THE HIGHEST RISK OF CELL TRAINING
APPEARS TO BE FROM SANTA CRUZ AND THE EASTERN HALF OF PIMA COUNTIES
INTO EASTERN PINAL...GRAHAM AND NORTHERN GREENLEE COUNTIES. IF
INITIAL THUNDERSTORM DEVELOPMENT IS STRONG AND PARTICULARLY
ORGANIZED...A FLASH FLOOD WATCH MAY BE REQUIRED SINCE THE MOUNTAINS
OF EASTERN PIMA...SANTA CRUZ AND GRAHAM COUNTIES HAVE RECEIVED HEAVY
RAIN A FEW TIMES THIS WEEK.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

AFTER AN ACTIVE AFTERNOON AND EVENING...THE RISK OF THUNDERSTORMS IS
EXPECTED TO DIMINISH SOMEWHAT OVER THE WEEKEND AS HIGH PRESSURE NEAR
EL PASO SHIFTS INTO NORTHERN MEXICO. THERE WILL BE PLENTY OF
MOISTURE STUCK OVER THE REGION...THOUGH...SO ISOLATED AND SLOW-MOVING
THUNDERSTORMS ARE STILL EXPECTED. THE HIGH IS THEN EXPECTED TO SHIFT
NORTH OR EAST OF THE REGION NEXT WEEK...LEADING TO A RATHER TYPICAL
MONSOON CONDITIONS.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

PYTLAK