Flash Flood Warning 100, NWS Tucson, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
254 AM MST THU AUG 24 2006

.SYNOPSIS...THE GENERAL FLOW PATTERN OVER THE DESERT SOUTHWEST WILL
PROVIDE SOUTHEAST ARIZONA WITH SEVERAL MORE DAYS OF WIDESPREAD
SHOWER AND THUNDERSTORM ACTIVITY. HIGH TEMPERATURES WILL REMAIN AT
OR SLIGHTLY BELOW NORMAL THIS WEEK.

&&

.DISCUSSION...A QUIET EARLY MORNING ACROSS SOUTHEAST ARIZONA WITH
SOME SCATTERED TO BROKEN MID LEVEL DEBRIS CLOUDINESS ACROSS MAINLY
CENTRAL SECTIONS OF MY FORECAST AREA. SOME ACTIVITY STILL ONGOING
WELL SOUTH IN SONORA MEXICO.

THE AIRMASS OVER THE REGION IS STILL QUITE MOIST WITH YESTERDAY
EVENINGS KTUS SOUNDING SHOWING A PRECIPITABLE WATER VALUE OF JUST
OVER AN INCH AND A HALF. WATER VAPOR IMAGERY AND UPPER AIR PLOTS
FROM YESTERDAY EVENING INDICATE THAT THE CENTER OF THE HIGH IS IN
THE GENERAL VICINITY OF NORTH CENTRAL TEXAS WITH THE RIDGE AXIS
EXTENDING INTO NORTHERN MEXICO. MEANWHILE...HURRICANE ILEANA IS IN
THE VICINITY OF 20.1 N LAT 113.7 W LONG WHICH IS A BIT OVER 300
MILES TO THE SOUTHWEST OF THE SOUTHERN TIP OF THE BAJA PENINSULA...
SO WAY TOO FAR TO HAVE ANY AFFECT ON THE DESERT SOUTHWEST. IN
ADDITION...THE HURRICANE CENTER IS FORECASTING ILEANA TO MOVE WEST
NORTHWEST AND EVENTUALLY WEAKEN CONSIDERABLY AS IT MOVES OVER COOLER
WATER IN THE EASTERN PACIFIC.

BACK TO ARIZONA...THE MODELS ARE NOW FORECASTING A CONTINUATION OF
MOISTURE BEING PULLED NORTHWARD INTO ARIZONA AROUND THE WESTERN
PERIPHERY OF THE HIGH...BUT A PACIFIC TROUGH IS PROGGED TO MOVE
ACROSS THE WESTERN STATES INTO THE WEEKEND. BOTH THE 00Z AND 18Z RUN
OF THE GFS HAVE INDICATED THAT AS THIS TROUGH MOVES NORTH OF THE
REGION IT WILL PUSH THE MOISTURE EAST INTO NEW MEXICO. THE ECMWF AND
THE CANADIAN HAVE A SIMILAR SOLUTION WITH THE TROUGH AXIS TO THE
EAST OF ARIZONA...BUT THE HIGH BEHIND IS NOT AS STRONG AS DEPICTED
IN THE GFS. THEREFORE WITH THE MODELS SHOWING A CONSENSUS DECIDED TO
TRIM BACK THE POPS FOR BOTH SATURDAY AND SUNDAY AS DRIER AIR PUSHES
INTO ARIZONA FROM THE WEST. SURROUNDING ARIZONA OFFICES HAVE ALSO
DONE LIKEWISE.

BEGINNING ON MONDAY AND CONTINUING THROUGH THE MIDDLE OF NEXT WEEK A
BACKDOOR FRONT...COMBINED WITH THE FLOW AROUND THE WESTERN FLANK OF
THE HIGH CENTERED OVER THE SOUTHEASTERN STATES WILL PULL MOISTURE
BACK ACROSS EASTERN ARIZONA. THIS WILL RESULT IN AN INCREASE IN RAIN
CHANCES INTO THE SCATTERED CATEGORY FOR CENTRAL AND EASTERN ZONES.

HIGH TEMPS WILL HOVER AROUND THE MID 90S FOR THE TUCSON AREA THROUGH
THE MIDDLE OF NEXT WEEK WHICH IS SLIGHTLY BELOW NORMAL FOR LATE
AUGUST. LOWS WILL REMAIN A FEW DEGREES ABOVE NORMAL.

&&

.HYDROLOGY...A FLASH FLOOD WATCH FOR THE GILA RIVER NEAR DUNCAN
CONTINUES IN EFFECT UNTIL 300 PM MST THIS AFTERNOON. ON TUESDAY
AFTERNOON THE GREENLEE EMERGENCY MANAGER REPORTED THAT A DIKE
STRUCTURE IN THE TOWN OF DUNCAN WAS EXPERIENCING EROSION DUE TO
ELEVATED RIVER STAGES. THE LOCATION OF THIS DIKE STRUCTURE IS NEAR
THE HIGH SCHOOL IN DUNCAN ON THE LEFT BANK OF THE GILA RIVER. IF THE
DIKE STRUCTURE WERE TO BE BREACHED...STATE HIGHWAY 70 NEAR THE HIGH
SCHOOL WOULD BE IMPASSABLE. FURTHERMORE...THE FIELDS BY THE HIGH
SCHOOL AND SEVERAL NEARBY HOMES COULD BE IMPACTED. THE STAGE READING
AT DUNCAN HAS DECREASED OVERNIGHT...BUT ANY ADDITIONAL RAINFALL IN
THE UPPER GILA WATERSHED IN NEW MEXICO THIS AFTERNOON WILL CAUSE
ADDITIONAL RISES OVER THE NEXT SEVERAL DAYS.

&&

.AVIATION...TAFS AND TWEBS ADEQUATELY COVER ALL SIGNIFICANT WEATHER
AT KTUS.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...FLASH FLOOD WATCH FOR THE GILA
RIVER IN DUNCAN (AZZ030) UNTIL 300 PM MST THIS AFTERNOON.

&&

MOLLERE

WEATHER.GOV/TUCSON

HAZARDOUS WEATHER OUTLOOK...CORRECTED TYPO
NATIONAL WEATHER SERVICE TUCSON AZ
545 AM MST THU AUG 24 2006

AZZ019-029-031>035-251400-
NORTHERN GREENLEE COUNTY-SOUTHEAST PINAL COUNTY-
WESTERN PIMA COUNTY-TOHONO OODHAM NATION-TUCSON METRO/MARANA/GREEN
VALLEY-SANTA CRUZ COUNTY-COCHISE COUNTY-
545 AM MST THU AUG 24 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
ARIZONA AND SOUTHEAST ARIZONA.

.DAY ONE...TODAY AND TONIGHT

HIGH PRESSURE CENTERED OVER NORTH CENTRAL TEXAS AND EXTENDING ACROSS
NORTHERN MEXICO WILL ALLOW SOUTH TO SOUTHWEST FLOW TO CONTINUE TO
PULL MOISTURE INTO ARIZONA TODAY. SHOWERS AND THUNDERSTORMS HAVE
ALREADY BEGUN TO DEVELOP ACROSS CENTRAL PORTIONS OF MY FORECAST AREA
FROM SOUTHWEST PINAL COUNTY AND EXTENDING INTO NORTHEAST PIMA
COUNTY...INCLUDING THE TUCSON AREA. THESE STORMS HAVE DEVELOPED
ALONG A BOUNDARY BETWEEN DRY AIR OVER NORTHERN BAJA AND NORTHWEST
SONORA...AND VERY MOIST AIR OVER CENTRAL AND EASTERN ARIZONA. EVEN
THOUGH ORGANIZED SEVERE STORMS ARE NOT ANTICIPATED TODAY...SOME OF
THE STORMS WILL LIKELY APPROACH OR EXCEED SEVERE LEVELS WITH A
POTENTIAL FOR PRODUCING DAMAGING WINDS AND HAIL. THE MID TO UPPER
LEVEL WINDS ARE RATHER WEAK TODAY...SO THE MAIN CONCERN WITH THESE
STORMS WILL BE HEAVY RAIN WHICH COULD RESULT IN LOCALIZED FLOODING.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. HOWEVER...THE FLOW
PATTERN WILL REMAIN FAVORABLE FOR THUNDERSTORMS EACH DAY...BUT WITH
LESS ACTIVITY EXPECTED ON SATURDAY AND SUNDAY.

.SPOTTER INFORMATION STATEMENT...

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

AZZ030-251400-
UPPER GILA RIVER VALLEY-
545 AM MST THU AUG 24 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST ARIZONA.

.DAY ONE...TODAY AND TONIGHT

...A FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 3 PM MST THIS
AFTERNOON...

THE FLASH FLOOD WATCH IS ASSOCIATED WITH A RISE ON THE GILA RIVER AT
DUNCAN. FOR MORE DETAILED INFORMATION CONCERNING THE WATCH REFER TO THE
LATEST ISSUANCE OF THE FLASH FLOOD WATCH UNDER THE HEADER PHXFFATWC
OR REFER TO OUR WEB PAGE AT WWW.WEATHER.GOV/TUCSON.

HIGH PRESSURE CENTERED OVER NORTH CENTRAL TEXAS AND EXTENDING ACROSS
NORTHERN MEXICO WILL ALLOW SOUTH TO SOUTHWEST FLOW TO CONTINUE TO
PULL MOISTURE INTO ARIZONA TODAY. SHOWERS AND THUNDERSTORMS HAVE
ALREADY BEGUN TO DEVELOP ACROSS CENTRAL PORTIONS OF MY FORECAST AREA
FROM SOUTHWEST PINAL COUNTY AND EXTENDING INTO NORTHEAST PIMA
COUNTY...INCLUDING THE TUCSON AREA. THESE STORMS HAVE DEVELOPED
ALONG A BOUNDARY BETWEEN DRY AIR OVER NORTHERN BAJA AND NORTHWEST
SONORA...AND VERY MOIST AIR OVER CENTRAL AND EASTERN ARIZONA. EVEN
THOUGH ORGANIZED SEVERE STORMS ARE NOT ANTICIPATED TODAY...SOME OF
THE STORMS WILL LIKELY APPROACH OR EXCEED SEVERE LEVELS WITH A
POTENTIAL FOR PRODUCING DAMAGING WINDS AND HAIL. THE MID TO UPPER
LEVEL WINDS ARE RATHER WEAK TODAY...SO THE MAIN CONCERN WITH THESE
STORMS WILL BE HEAVY RAIN WHICH COULD RESULT IN LOCALIZED FLOODING.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. HOWEVER...THE FLOW
PATTERN WILL REMAIN FAVORABLE FOR THUNDERSTORMS EACH DAY...BUT WITH
LESS ACTIVITY EXPECTED ON SATURDAY AND SUNDAY.

.SPOTTER INFORMATION STATEMENT...

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