Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 291640
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
939 AM MST SAT AUG 29 2015

.SYNOPSIS...A CHANCE OF SHOWERS AND THUNDERSTORMS OVER THE WEEKEND
INTO EARLY NEXT WEEK. GRADUALLY DRIER CONDITIONS WILL THEN LIMIT
THUNDERSTORMS TO EAST OF TUCSON THE SECOND HALF OF NEXT WEEK. HOTTER
THAN AVERAGE TEMPERATURES FOR THE NEXT FEW DAYS FOLLOWED BY
TEMPERATURES FALLING TO NEAR AVERAGE AROUND THE MIDDLE OF THE
UPCOMING WEEK.

&&

.DISCUSSION...WILL SEE PLENTY OF SUNSHINE TODAY WITH HIGH
TEMPERATURES SEVERAL DEGREES ABOVE NORMAL AGAIN. THE MORNING UPPER-
AIR SOUNDING AT KTUS SHOWED VERY LITTLE CAPE TO WORK WITH AND THE
WINDS ALOFT WERE VERY LIGHT. NOT FAVORABLE CONDITIONS FOR WIDESPREAD
THUNDERSTORM ACTIVITY THIS AFTERNOON. THUS...JUST LOOKING AT
ISOLATED COVERAGE SIMILAR TO YESTERDAY. PLEASE REFER TO THE
ADDITIONAL SECTIONS FOR MORE DETAILS.

&&

.AVIATION...VALID THRU 30/18Z.
MOSTLY SKC EARLY. BY LATE MORNING CLOUD COVERAGE INCREASING WITH
BASES 8 TO 12 KFT. ISOLD SHRA/TSRA WILL BE POSSIBLE AFTER
29/20Z...INCREASING IN COVERAGE AS THE AFTERNOON/EVENING PROGRESSES.
BRIEF MVFR CONDITIONS AND GUSTY WINDS OF 30 TO 40 KTS WILL BE
POSSIBLE IN AND AROUND STRONGER STORMS. OUTSIDE OF THUNDERSTORM
INFLUENCE SURFACE WINDS WILL GENERALLY BE UNDER 10 KTS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...ISOLATED SHOWERS AND THUNDERSTORMS FOR MUCH OF
SOUTHEAST ARIZONA THIS AFTERNOON AND EVENING. THIS TREND WILL
CONTINUE INTO EARLY NEXT WEEK...WITH DAILY AFTERNOON AND EVENING
STORMS EXPECTED TO BE THE NORM. STARTING MONDAY STORMS WILL TEND TO
BE MORE FOCUSED OVER EASTERN ZONES...WITH SIGNIFICANTLY DIMINISHED
THUNDERSTORM ACTIVITY FROM WEDNESDAY ON. THUNDERSTORMS ARE EXPECTED
TO BE WET AND AS IS TYPICAL MAY PRODUCE STRONG...GUSTY AND ERRATIC
WINDS WITH THE STRONGER THUNDERSTORMS.

THROUGH SUNDAY GENERALLY LIGHT TERRAIN DRIVEN WINDS ARE EXPECTED.
FROM MONDAY ONWARD A WEST TO SOUTHWEST FLOW WILL GRADUALLY DEVELOP
ACROSS ARIZONA.  THE STRONGEST WINDS WILL BE ACROSS ZONE
150...PEAKING IN THE 15-20 MPH RANGE.  THIS FLOW WILL ALSO STEADILY
PUSH THE MOISTURE OUT OF THE REGION FOR DECREASING CHANCES OF
THUNDERSTORMS WEDNESDAY THROUGH FRIDAY.

&&

.CLIMATE...TUCSON AIRPORT CLOSING IN ON A CONSECUTIVE STREAK RECORD.
YESTERDAY MARKED THE 80TH STRAIGHT DAY THAT THE LOW TEMPERATURE WAS
70 DEGREES OR WARMER. THE RECORD IS 81 STRAIGHT DAYS SET TWO YEARS
AGO. OFFICIAL NWS FORECAST HAS THIS RECORD BEING BROKEN ON SUNDAY.

&&

.PREV DISCUSSION...THE LARGER SCALE PICTURE IS SHUFFLING A BIT WITH
A WEAKENING RIDGE AXIS NEARLY OVERHEAD AND A VERY STRONG TROUGH
THROUGH HIGHER LATITUDE AND MID TIER STATES NORTHWEST OF THE AREA.
THIS WILL HELP FOCUS OUR ATTENTION FOR STORMS OVER THE NEXT 3 DAYS
TO PARTICULAR AREAS.

FOR TODAY EXPECT THE H7 THETA-E RIDGE NEAR NORTHERN SONORA TO EXTEND
INTO AREAS WEST OF TUCSON THIS AFTERNOON FOR OUR FIRST AREA OF
INTEREST OVER THE TOHONO O`ODHAM NATION. IN ADDITION...SOME WEAK
DIFFLUENCE ALOFT ON THE EASTERN FLANK OF THE H3 RIDGE INFLECTION
WILL HELP WITH STORMS OVER EASTERN AREAS...FOR OUR SECOND MAIN AREA
OF INTEREST OVER COCHISE COUNTY THIS AFTERNOON. STILL WEAK FLOW
OVERALL BUT WE ARE GETTING SOME ADDITIONAL HELP WITH THESE FEATURES
TODAY.

FOR SUNDAY...THE H7 THETA-E RIDGE SHIFTS EASTWARD TO A POSITION NEAR
EASTERN PIMA AND SANTA CRUZ COUNTIES SUNDAY AFTERNOON. THAT WILL BE
OUR MAIN AREA OF FOCUS SUNDAY AFTERNOON.

BY MONDAY AND TUESDAY...THE RIDGE RECONSOLIDATING FURTHER EAST WILL
SEE H7 THETA-E INFLUENCES MOST EVIDENT IN AREAS EAST OF TUCSON.

BY WEDNESDAY THROUGH THE END OF THE WEEK...THE WESTERLY FLOW WILL
HAVE TAKEN IT`S TOLL AS AN ANOMALOUSLY STRONG MEAN TROUGH POSITION
NORTH OF US WILL SLOWLY DRIVE MOISTURE TO THE EAST AND SOUTHEAST.
MOISTURE WON`T BE FAR AWAY...BUT DEFINITELY NOT A GOOD PATTERN FOR
MONSOON ACTIVITY...EVEN LATE IN THE SEASON.

&&

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

&&

$$

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