Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 021021
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
300 AM MST WED SEP 2 2015

.SYNOPSIS...AMPLE MOISTURE IN COMBINATION WITH SEVERAL DISTURBANCES
WILL CREATE ELEVATED CHANCES OF SHOWERS AND THUNDERSTORMS THROUGH
SATURDAY. WE WILL THEN MAINTAIN ENOUGH MOISTURE FOR ISOLATED TO
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS INTO NEXT WEEK.

&&

.DISCUSSION...WE`VE ESTABLISHED A VERY NIFTY SOUTHWESTERLY TO
SOUTHERLY FLOW BETWEEN LARGE SCALE FEATURES AS THE PERSISTENT MEAN
TROUGH POSITION REMAINS THROUGH THE REGION TO OUR NORTHWEST (A NICE
LITTLE LOW AT THE BASE OFF THE SOUTHERN CALIFORNIA COAST) AND THE
RIDGE AXIS PHASES A TAD FURTHER EAST. THIS OPENS UP A FETCH THAT
REACHES ALL THE WAY DOWN TO THE TROPICAL ACTIVITY SOUTH OF BAJA OFF
THE WEST COAST OF MEXICO. THAT DOES NICE THINGS FOR MAINTAINING OUR
MOISTURE. IT ALSO BRINGS IN 2 EMBEDDED IMPULSES IN THIS FLOW TODAY
AND THEN AGAIN THURSDAY.

OVERALL A WELL ABOVE AVERAGE THUNDERSTORM DAY EXPECTED TODAY AS THE
FIRST IMPULSE PUSHES IN FROM THE SOUTH...WITH A TRAJECTORY FAVORING
SANTA CRUZ...EASTERN PIMA...AND WESTERN COCHISE COUNTY THIS
AFTERNOON AND MUCH OF THE REST OF THE AREA THIS EVENING. WATCH FOR
ORGANIZED OUTFLOWS AND HEAVY RAIN WITH ISOLATED WET MICROBURST
POTENTIAL. THE OUTFLOWS MAY CREATE SOME DUST ISSUES IN PORTIONS OF
PIMA AND PINAL COUNTIES.

THE FLOW WILL BE STRONG ENOUGH TO RESET THE ATMOSPHERE FOR
THURSDAY...AND WITH A SECOND IMPULSE COMING UP FROM THE SOUTH LATE
THURSDAY AFTERNOON AND EVENING...THE POTENTIAL IS THERE FOR A MORE
WIDESPREAD AND STRONGER CONVECTIVE PERIOD THAN TODAY. EVEN BETTER
STORM ORGANIZATION POSSIBLE WITH ANOTHER ELEVATED RISK FOR WET
MICROBURST ACTIVITY AND STRONG ORGANIZED OUTFLOW.

AFTER THAT DETAILS BECOME LESS CLEAR...HOWEVER IN GENERAL WE WILL
MAINTAIN THIS FAVORABLE FLOW INTO THE WEEKEND WITH EACH DAY HAVING
THE POTENTIAL FOR ABOVE AVERAGE THUNDERSTORM COVERAGE AS WE CONTINUE
TO IMPORT MOISTURE AND ENERGY FROM OUR SEPTEMBER TROPICAL SEEDING
ZONE OFF THE MEXICAN COAST.

&&

.AVIATION...VALID THRU 03/12Z.
SCATTERED TO NUMEROUS TSRA/SHRA ACROSS MUCH OF SE ARIZONA WEDNESDAY
AFTERNOON AND EVENING. BRIEF MVFR CONDITIONS AND WIND GUSTS OF 35 TO
45 KTS WILL OCCUR WITH THE STRONGER THUNDERSTORMS.
OTHERWISE...EXPECT LAYERED CLOUDS MOSTLY BETWEEN 10-15K FT AGL AND
SURFACE WIND GENERALLY LESS THAN 10 KTS INTO TONIGHT. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
MUCH OF SOUTHEAST ARIZONA THROUGH SATURDAY. LOCALLY HEAVY RAINFALL
AND BRIEF GUSTY WINDS WILL ACCOMPANY THE STRONGER THUNDERSTORMS.
THEREAFTER...ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING
THUNDERSTORMS WILL PREVAIL SUNDAY THROUGH TUESDAY.

&&

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

&&

$$

MEYER/RASMUSSEN

VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON


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