Severe Thunderstorm Warning 67, NWS Tucson, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
200 PM MST THU AUG 19 2004

SOUTHEAST ARIZONA FORECAST DISCUSSION

.SYNOPSIS...MOISTURE WILL REMAIN OVER THE AREA FOR TYPICAL AFTERNOON
AND EVENING THUNDERSTORMS THROUGH FRIDAY. OTHERWISE...EXPECT NEAR
NORMAL DAYTIME TEMPERATURES THIS WEEK. A SLIGHT INCREASE IN MOISTURE
WILL BEGIN BY EARLY NEXT WEEK FOR A SLIGHTLY BETTER CHANCE OF
THUNDERSTORMS.

&&

.DISCUSSION...WATER VAPOR IMAGERY SHOWS A SHORTWAVE MOVING THROUGH
ARIZONA AT THE PRESENT TIME. VISIBLE IMAGERY BETWEEN ABOUT 17Z TO
19Z SHOWED A NICE CIRCULATION IN THE CLOUD COVER GENERALLY BETWEEN
PRESCOTT AND PAYSON. CLOSER TO HOME SCATTERED STORMS HAVE DEVELOPED
OVER MAINLY SOUTHERN GRAHAM AND MUCH OF COCHISE COUNTY. NONE OF THE
MODELS REALLY PICKED UP ON THIS SHORTWAVE VERY WELL...AND FOR THIS
AFTERNOON THEY ARE NOT EVEN SHOWING QPF PAINTED OVER AREAS THAT ARE
CURRENTLY RECEIVING RAINFALL (GRAHAM AND COCHISE COUNTIES).

THE WEAK SHORTWAVE ENERGY THE MODELS ARE PICKING UP ON IS SHOWN TO
MOVE THROUGH THE REGION AND WEAKEN AS IT DOES SO. BY EARLY SATURDAY
AN UPPER LEVEL RIDGE BEGINS TO DEVELOP OVER THE SOUTHWEST AS A
CLOSED LOW DEVELOPS OFF THE CALIFORNIA COAST. THE RESULT OF THIS IS
THAT DRIER AIR SHOULD FILTER INTO THE REGION AND THE CONVECTIVE
ACTIVITY SHOULD REMAIN TO THE EAST OF THE REGION...BUT CANT RULE
OUT A SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS TO DEVELOP MAINLY EAST
OF THE TUCSON AREA. BY LATE SUNDAY/EARLY MONDAY MOISTURE IS
ADVERTISED BY THE MODELS TO BEGIN TO RETURN TO THE AREA AS THE UPPER
LOW OFF THE CALIFORNIA COAST MOVES TO A POSITION JUST WEST OF THE
NORTHERN BAJA PENINSULA. THIS WILL ALLOW MORE OF A SOUTHERLY FLOW TO
DEVELOP WHICH WILL INCREASE MOISTURE. THEREFORE EXPECT THE THREAT
FOR SHOWERS TO DECREASE OVER THE WEEKEND BEFORE PICKING BACK UP
SLIGHTLY BY EARLY IN THE UPCOMING WEEK.

BY LATE IN THE EXTENDED FORECAST THE GFS IS SHOWING A SWATH OF
MOISTURE SPILLING INTO THE REGION. HOWEVER...THIS LATEST SOLUTION IS
CONSIDERABLY DIFFERENT THAN PREVIOUS RUNS SO WILL HOLD OFF ON
SHOWING AN UPSWING IN POP FOR LATE IN THE WEEK. IF SUBSEQUENT MODEL
RUNS CONTINUE TO SHOW A SIMILAR SOLUTION WE WILL HAVE TO REVISIT
THIS ISSUE.

TEMPS SHOULD REMAIN NEAR NORMAL FOR THE NEXT WEEK...MID TO UPPER 90S
FOR HIGHS...LOWER TO MID 70S FOR LOWS ACROSS DESERTS/VALLEYS.

&&

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

MOLLERE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1145 AM MST THU AUG 19 2004

AZZ019-029>035-200700-
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-
1145 AM MST THU AUG 19 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ARIZONA

.DAY ONE...TODAY

SYNOPSIS...ACTIVITY WILL BE SIMILAR TO YESTERDAY. DRIER AIR
CONTINUES TO MOVE SLOWLY INTO SOUTHEAST ARIZONA...HOWEVER...THE
ATMOSPHERE REMAINS UNSTABLE.  THERE IS A SLIGHT RISK FOR ISOLATED
SEVERE THUNDERSTORMS...THOUGH THE RISK OF HEAVY RAINFALL IS
DECREASED FROM YESTERDAY.

DISCUSSION...THE MORNING SOUNDING CONTINUES TO SHOW A DRYING
TREND...WITH PRECIPITABLE WATER JUST UNDER AN INCH.  HOWEVER...THE
ATMOSPHERE REMAINS AS UNSTABLE AS IT HAS BEEN THE PAST COUPLE DAYS.
IN FACT...THINGS HAVE GOTTEN OFF TO AN EARLY START AS EXTREME
WESTERN PORTIONS OF PINAL COUNTY HAVE ALREADY SEEN SOME ACTIVITY.
WITH CONDITIONS BEING A LITTLE DRIER THAN THEY WERE YESTERDAY...THE
RISK OF FLASH FLOODING WILL BE LIMITED TO THOSE AREAS THAT HAVE
ALREADY SEEN SIGNIFICANT RAINFALL OVER THE PAST 7 DAYS.  WITH THE
DRIER AIR SEEPING INTO SOUTHEAST ARIZONA AT THE SURFACE...BUT
MOISTURE ALOFT...THERE WILL STILL BE A RISK FOR SCATTERED
THUNDERSTORM ACTIVITY TODAY.  AS MENTIONED ABOVE...THOUGH...THE RISK
FOR SEVERE THUNDERSTORMS WILL BE ISOLATED.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

DRIER AIR WILL CONTINUE TO SEEP SLOWLY INTO ARIZONA FOR THE
REMAINDER OF THE WEEK AND INTO THE WEEKEND DUE TO A SOUTHWESTERLY
FLOW ALOFT...THUS LIMITING THUNDERSTORM ACTIVITY.
HOWEVER...MOISTURE IS POISED TO RETURN TO THE AREA STARTING LATE
SUNDAY AND BUILDING UP INTO THE MIDDLE OF NEXT WEEK.  THIS WILL
ALLOW FOR SOME INCREASED ACTIVITY TO RETURN TO SOUTHEAST ARIZONA BY
WEDNESDAY.

.SPOTTER INFORMATION STATEMENT...

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

SMR

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON AZ
1040 AM MST THU AUG 19 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

0315 PM     FLASH FLOOD      RIO RICO                31.48N 110.98W
08/13/2004                   SANTA CRUZ         AZ   COUNTY OFFICIAL

            7 HOMES FLOODED NEAR FRONTAGE ROAD.

&&

MSS