Area Forecast Discussion
Issued by NWS Tucson, AZ

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000
FXUS65 KTWC 271640
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
940 AM MST SAT JUN 27 2015

.SYNOPSIS...AMPLE MOISTURE WILL MAINTAIN THE DAILY CYCLE OF MAINLY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS THIS WEEKEND AND
DURING THE UPCOMING WEEK. THE POTENTIAL EXISTS THIS AFTERNOON AND
EVENING FOR AREAS OF BLOWING DUST ESPECIALLY FROM TUCSON WEST AND
NORTHWEST DUE TO OUTFLOW WINDS. OTHERWISE...DAYTIME TEMPERATURES
WILL TREND A FEW DEGREES BELOW NORMAL DURING THE UPCOMING WEEK.

&&

.DISCUSSION...VISIBLE SATELLITE IMAGERY DEPICTED MOSTLY CLEAR SKIES
ACROSS THE WHITE MOUNTAINS...WITH PARTLY CLOUDY TO MOSTLY CLOUDY
SKIES ELSEWHERE AT THIS TIME. THICKER MAINLY CIRRIFORM CLOUDS WERE
ACROSS WRN/CENTRAL PIMA COUNTY WEST OF TUCSON. DEWPOINTS AT LOWER
ELEVATIONS VALID 16Z GENERALLY RANGED FROM THE MID 50S-LOWER 60S
F... AND THESE TEMPS WERE NEARLY 2-4 DEGS F OR SO HIGHER VERSUS 24
HOURS AGO. SURFACE TEMPS VALID 16Z WERE ABOUT 2-6 DEGS F COOLER
VERSUS THIS TIME FRI. 27/12Z KTWC SOUNDING PRECIP WATER VALUE WAS
1.38 INCHES...OR NEARLY IN THE 95TH PERCENTILE OF PRECIP WATER
VERSUS CLIMATOLOGY. MUCAPE YIELDED A VALUE OF 910 J/KG...AND A
PRONOUNCED ELY MID-LEVEL FLOW WAS OBSERVED. 27/12Z UPPER AIR PLOTS
DEPICTED HIGH-AMPLITUDE RIDGE OVER THE WRN CONUS WITH 596 DM HIGH
CENTERED OVER NERN NEVADA/NWRN UTAH. MODERATE TO STRONG ELY/NELY
FLOW PREVAILED IN THE 700-300 MB LAYER ACROSS SE ARIZONA.

VARIOUS 27/12Z NWP SOLUTIONS CONCUR WITH THE INHERITED OFFICIAL
FORECAST DEPICTING THE POTENTIAL FOR AN ACTIVE PERIOD OF SHOWERS/
TSTMS LATER TODAY INTO THIS EVENING. THE FAVORED AREA FOR INITIAL
DEVELOPMENT SHOULD BE ACROSS THE WHITE MOUNTAINS LIKELY BEFORE 19Z.
ANY SHOWERS/TSTMS WILL THEN MOVE WWD GIVEN THE AFOREMENTIONED MID-
LEVEL STEERING FLOW.

ANOTHER FAVORED AREA FOR SHOWERS/TSTMS CLUSTERS APPEARS TO BE SOUTH-
TO-SOUTHWEST OF THE TUCSON METRO AREA EARLY THIS AFTERNOON. 27/15Z
HRRR DEPICTS A LARGE COMPLEX TO BE OVER THE TOHONO O`ODHAM NATION
AND APPROACHING WRN PIMA COUNTY AROUND 22Z OR SO. IF THIS COMPLEX IS
REALITY...THERE WOULD BE A FAIRLY HIGH LIKELIHOOD FOR AREAS OF
BLOWING DUST WEST OF TUCSON AS PER THE INHERITED OFFICIAL FORECAST.

THEREAFTER...ADDITIONAL SHOWERS/TSTMS COMPLEXES IN THE VICINITY OF
THE TUCSON METRO AREA WOULD HOLD THE PROMISE FOR SIGNIFICANT BLOWING
DUST TO OCCUR...ESPECIALLY ALONG THE INTERSTATE 10 CORRIDOR
ESPECIALLY FROM MARANA NWWD INTO SOUTH CENTRAL PINAL COUNTY. A
BLOWING DUST ADVISORY THAT WAS ISSUED BY THE MIDNIGHT SHIFT REMAINS
IN EFFECT FROM 3 PM THIS AFTERNOON TO 8 PM MST THIS EVENING FOR WRN
PIMA COUNTY...THE TOHONO O`ODHAM NATION...THE TUCSON METRO AREA AND
SOUTH CENTRAL PINAL COUNTY.

GIVEN THE AVAILABLE MOISTURE...THE PRONOUNCED MID-LEVEL STEERING
FLOW...AND AN APPROACHING VORT TROUGH OVER SRN NEW MEXICO...THERE IS
ALSO THE POTENTIAL FOR AT LEAST A FEW SEVERE THUNDERSTORMS CAPABLE
OF PRODUCING DOWN BURSTS LATER TODAY AND THIS EVENING. LOCALIZED
FLOODING MAY ALSO OCCUR. HOWEVER...GIVEN THE EXPECTED FAIRLY FAST
WWD MOTIONS...WIDESPREAD FLOODING SHOULD BE MITIGATED. A SLIGHT
CHANCE OF SHOWERS/TSTMS WILL CONTINUE ACROSS THE AREA LATE TONIGHT
INTO EARLY SUN MORNING.

REGARDING THE REST OF THE FORECAST PERIOD...QUASI-STATIONARY UPPER
HIGH OVER THE WRN CONUS WILL MAINTAIN ADEQUATE MOISTURE AND A
FAVORABLE FLOW REGIME TO MAINTAIN THE DAILY CYCLE OF MAINLY
AFTERNOON AND EVENING SHOWERS/TSTMS THRU THE UPCOMING WEEK AND INTO
NEXT WEEKEND.

HIGH TEMPS THIS WEEKEND WILL BE QUITE CLOSE TO SEASONAL NORMALS...
THEN HIGH TEMPS DURING THE UPCOMING WORK WEEK ARE FORECAST TO BE
GENERALLY A FEW DEGS BELOW NORMAL.

&&

.AVIATION...VALID THRU 28/18Z.
SCTD -SHRA/-TSRA DEVELOPING AROUND 27/17Z FIRST OVER THE WHITE
MOUNTAINS AND NEAR SASABE/NOGALES THEN SPREADING ELSEWHERE THRU
28/03Z. WITH CONVECTION EXPECT SCT-BKN 6-8K FT WITH ADDITIONAL BKN
LAYERS ABOVE 10K FT. ALSO EXPECT WIND GUSTS OF 35-45 KTS ASSOCIATED
WITH TSRA AND LCL AREAS OF 1SM BLDU...MAINLY W AND NW OF KTUS
BETWEEN 27/20Z AND 28/02Z. OTHERWISE...SFC WIND LESS THAN 12 KTS.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...TODAY WILL BE A VERY BUSY CONVECTIVE DAY WITH
THUNDERSTORMS FIRST DEVELOPING OVER THE WHITE MOUNTAINS...ZONE
153...AND EASTERN ZONE 150/SW ZONE 151 BY EARLY AFTERNOON. THEN
STORMS ARE EXPECTED TO FILL IN ACROSS THE REMAINDER OF THE AREA
THROUGH THE AFTERNOON AND EARLY EVENING HOURS. THERE IS AN ENHANCED
THREAT OF STRONG DOWN BURST WINDS TODAY WITH INDIVIDUAL STORMS...
MAINLY MID AFTERNOON THROUGH EARLY THIS EVENING. GENERAL STORM
MOTION WILL BE TO THE WEST FOR MOST STORMS WHILE SLOW MOVING STORMS
WILL BE CAPABLE OF A PERIOD OF HEAVY RAIN.

BEYOND THAT...MONSOONAL MOISTURE WILL REMAIN OVER THE REGION IN A
GENERALLY EAST TO WEST FLOW REGIME FOR SCATTERED AFTERNOON AND
EVENING CONVECTION EACH DAY THROUGH NEXT WEEK WITH THE TYPICAL
THUNDERSTORM THREATS. GENERALLY LIGHT TERRAIN WINDS OUTSIDE
THUNDERSTORM INFLUENCES.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
    BLOWING DUST ADVISORY FROM 3 PM THIS AFTERNOON TO 8 PM MST THIS
    EVENING FOR AZZ501-502-504-505.

&&

$$

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

DISCUSSION...FRANCIS
AVIATION/FIRE WEATHER...CERNIGLIA



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