Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 251021
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
315 AM MST THU JUN 25 2015

.SYNOPSIS...SOUTHEAST ARIZONA NOW HAS ENOUGH MOISTURE FOR A CHANCE
OF SHOWERS AND THUNDERSTORMS TODAY AND FRIDAY. SOME STORMS WILL
GENERATE STRONG WINDS WITH AREAS OF BLOWING DUST POSSIBLE. A
STRONGER EASTERLY FLOW WITH DEEPER MOISTURE WILL BRING BETTER
THUNDERSTORM COVERAGE AND A MUCH BETTER CHANCE OF SUSTAINING STORMS
IN VALLEY LOCATIONS OVER THE WEEKEND INTO EARLY NEXT WEEK.

&&

.DISCUSSION...PLENTY OF DEBRIS CLOUD ACROSS SOUTHEAST ARIZONA FROM
THE UPSWING IN THUNDERSTORM ACTIVITY OVER THE PAST 15 HOURS. NO
SURPRISES AS WE SAW STORMS THAT WERE EXPLOSIVE OVER THE MOUNTAINS
BUT HAD SOME DIFFICULTY IN VALLEY LOCATIONS FURTHER WEST.

ANOTHER SURGE PUSHING UP THE GULF...AS OF 2:30 AM KYUX RADAR VAD
WIND PROFILE SUGGESTED IT WAS UP TO 3K FEET AGL DEEP THAT FAR
NORTH...BUT THERE ARE HINTS OF INFLUENCES AS HIGH AS 6K FEET DEEP
PUSHING INTO THE NORTHERN GULF ON BOTH THE GOES HIGH DENSITY WIND
ESTIMATES AND THE CIRA LAYERED PRECIPITABLE WATER ANALYSIS AT THE
850-700MB LAYER (THROUGH NASA SPORT). THIS MAY HELP SUSTAIN STORM
PROPAGATION A LITTLE DEEPER INTO THE WESTERN DESERTS LATE THIS
AFTERNOON AND EVENING. THIS IS ALSO HINTED AT BY THE 06Z UOFA WRF-
NAM THAT WE`RE JUST GETTING A LOOK AT. OTHERWISE THERE WILL STILL BE
SOME VALLEY LOCATIONS THAT STRUGGLE THIS AFTERNOON WITH A DRIER
LOWER LEVEL REGIME FURTHER EAST. FOR EXAMPLE...THE SURROUNDING
MOUNTAINS LIT UP LIKE A CHRISTMAS TREE IN EASTERN PIMA COUNTY
YESTERDAY...BUT NOT MUCH MADE IT INTO TUCSON METRO. ANOTHER DAY TO
WATCH FOR DUSTY OUTFLOWS IN THE VALLEYS AND ISOLATED SEVERE
POTENTIAL FROM MICROBURST ACTIVITY (MAINLY NEAR THE MOUNTAINS).

AS WE SHIFT BACK TO A PATTERN DOMINATED BY A STRONG RIDGE OVER THE
GREAT BASIN...FRIDAY WILL BE A TRANSITION DAY AS THE HIGH CENTER
CONSOLIDATES THROUGH THE REGION AND THEN NORTH OF US. A RELATIVE
DOWN DAY IS EXPECTED COVERAGE WISE...WITH SIGNIFICANT ACTIVITY BUT
MAINLY NEAR THE MOUNTAINS AND FAVORING BORDER AREAS.

BY THE WEEKEND A MUCH DEEPER AND SUSTAINED EASTERLY TO SOUTHEASTERLY
FLOW SHOULD BRING MORE WIDESPREAD THUNDERSTORM COVERAGE WITH A MUCH
GREATER CHANCE IN GENERAL OF SUSTAINING THUNDERSTORM ACTIVITY IN
VALLEY AND LOWER DESERT LOCATIONS. THERE IS ALSO A HINT OF ANOTHER
WEAK EASTERLY WAVE ROTATING IN OUR DIRECTION ON SUNDAY AS SUNDAY
STARTS TO LOOK LIKE A PARTICULARLY BUSY DAY.

WE EXPECT TO KEEP SOME VARIATION OF THAT PATTERN THROUGH MUCH OF THE
COMING WEEK. ANYONE WITH OUTDOOR PLANS THIS WEEKEND SHOULD
ANTICIPATE THE POTENTIAL FOR STRONG WINDS...LOCALLY HEAVY
RAINFALL...AND FREQUENT LIGHTNING.

&&

.AVIATION...VALID THRU 26/12Z.
CLEARING EARLY THIS MORNING AS DEBRIS CLOUD SLOWLY DISSIPATES.
EXPECT ISOLATED -TSRA/-SHRA EAST OF KTUS DEVELOPING LATE THIS
MORNING...THEN SCATTERED TO NUMEROUS TSRA/SHRA SHOULD OCCUR ACROSS
MUCH OF SOUTHEAST ARIZONA THURSDAY AFTERNOON AND THURSDAY
EVENING...ESPECIALLY IN AND AROUND MOUNTAIN LOCATIONS. THE POTENTIAL
EXISTS FOR BRIEF THUNDERSTORM WIND GUSTS MAINLY IN THE 40-45 KT
RANGE DURING THE AFTERNOON AND EARLY EVENING. OTHERWISE...CLOUD
DECKS WILL GENERALLY BE AT OR ABOVE 10K FT AGL WITH TYPICAL DIURNAL
WIND TRENDS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...MONSOONAL MOISTURE WILL BE DIRECTED INTO SOUTHEAST
ARIZONA FOR THE NEXT SEVERAL DAYS WITH THUNDERSTORM ACTIVITY
CONTINUING TO RAMP UP...ESPECIALLY THIS WEEKEND. INITIAL THREAT FROM
THUNDERSTORMS WILL BE STRONG GUSTY OUTFLOWS AND DRY LIGHTNING UNTIL
MOISTURE BECOMES MORE ENTRENCHED.  WIND GUSTS OF 35-45 MPH WILL BE
FAIRLY COMMON WITH THE POTENTIAL FOR THE STRONGEST AFTERNOON AND
EARLY EVENING STORMS TO PRODUCE WINDS IN EXCESS OF 50 MPH.

&&

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

&&

$$

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

MEYER/RASMUSSEN



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