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000
FXUS65 KTWC 180342 CCA
AFDTWC

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE TUCSON AZ
842 PM MST FRI MAY 17 2013

.SYNOPSIS...A LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION TONIGHT
AND SATURDAY. EXPECT GUSTY WINDS AND SOMEWHAT COOLER TEMPERATURES
AGAIN SATURDAY. HIGH PRESSURE OVER THE WESTERN UNITED STATES
WILL THEN DEVELOP EARLY NEXT WEEK AND GUIDE TEMPERATURES BACK TO
WELL ABOVE AVERAGE.

&&

.DISCUSSION...THE GUSTY WINDS OF THIS AFTERNOON HAD PRETTY MUCH
DIMINISHED IN SPEED LATE THIS EVENING. SATELLITE IMAGERY WAS SHOWING
A BATCH OF MID AND HIGH LEVEL CLOUDS ASSOCIATED WITH THE TAIL
END OF A WEATHER SYSTEM SPREADING INTO SOUTHEAST ARIZONA. EXPECT
THIS CLOUDINESS TO PASS THROUGH THE AREA TONIGHT INTO EARLY SATURDAY
MORNING. NOT ENOUGH MOISTURE THIS FAR SOUTH TO WARRANT THE MENTION
OF MEASURABLE RAINFALL...BUT A LOT OF VIRGA AND POSSIBLY A DROP OR
TWO REACHING THE GROUND OVERNIGHT. OTHERWISE...FORECAST LOOKED ON
GOOD TRACK SO NO UPDATES EXPECTED THIS EVENING.

&&

.AVIATION...VFR CONDITIONS THROUGH THE NEXT 24 HOURS. SCT-BKN MAINLY
ABOVE 15K FT THRU  SFC WIND DIMINISHING THRU 18/10Z. SW-W WINDS
10-20 KTS WITH HIGHER GUSTS AGAIN TOMORROW AFTER 18/18Z. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...A DRY UPPER LEVEL TROUGH IS MOVING INTO THE REGION
WILL PASS OVERHEAD SATURDAY AND MOVE EAST OF THE REGION SUNDAY.
WHILE THIS SYSTEM WILL BE DRY...TEMPERATURES WILL COOL OFF THIS
WEEKEND WITH CONTINUED BREEZY TO LOCALLY WINDY CONDITIONS IN THE
AFTERNOON.  THIS SYSTEM WILL BE DRY BUT WILL COOL TEMPERATURES AND
KICK UP A BREEZE TODAY THROUGH SUNDAY AFTERNOONS WITH LOCALLY WINDY
CONDITIONS POSSIBLE EACH AFTERNOON. AFTERNOON MIN RH VALUES WILL BE
IN THE 5-15% RANGE BUT OVERALL...EXPECT WINDS TO REMAIN JUST BELOW
RED FLAG THRESHOLDS. HOWEVER...AREAS AROUND ALPINE MAY REACH RED
FLAG THRESHOLDS INTO EARLY THIS EVENING. THUS A RED FLAG WARNING IS
IN EFFECT FOR THE ALPINE AREA THIS AFTERNOON INTO EARLY THIS
EVENING. DRY CONDITIONS WILL CONTINUE INTO THE MIDDLE OF NEXT WEEK
WITH ABOVE NORMAL TEMPERATURES INTO WEDNESDAY.

&&

.PREV DISCUSSION...COOLER AIR...AT LEAST FOR MAY STANDARDS...WILL
MOVE INTO ARIZONA THIS WEEKEND. AN APPROACHING UPPER LEVEL TROUGH IS
PUSHING THE COOLER AIR INTO ARIZONA. THE TROUGH AXIS IS CURRENTLY
STILL WEST OF ARIZONA BY A FEW HUNDRED MILES...BUT THE AXIS SHOULD
REACH WESTERN AZ THIS AFTERNOON OR EVENING. IN ADDITION TO THE
COOLING TREND...ALSO ANTICIPATE INCREASING HIGH CLOUD COVER TONIGHT
THROUGH SATURDAY. OTHERWISE...EXPECT MOSTLY CLEAR SKIES AND
SEASONABLE CONDITIONS EARLY NEXT WEEK AS SHORTWAVE RIDGING SET UP
BEHIND THE EXITING TROUGH.

THE RIDGING WILL ALLOW WARMER CONDITIONS TO DEVELOP TUESDAY THROUGH
THURSDAY AND TUCSON WILL AGAIN FLOAT NEAR TRIPLE DIGITS FOR HIGH
TEMPS. THE AIRMASS IS NOT THAT ANOMALOUS FOR THIS TIME OF YEAR SO
EXPECTING HIGH TEMPS TO RISE ONLY 4 OR 5 DEGREES ABOVE NORMAL. A
DEEP TROUGH WILL DEVELOP OVER THE PACIFIC NORTHWEST SETTING UP AN
OMEGA BLOCK BY LATE IN THE WEEK. THIS WILL KEEP PERSISTENT SW FLOW
ALOFT. THE PRESSURE GRADIENT RESULTING FROM THE DEEPENING NW TROUGH
AND CENTRAL US RIDGE WILL ALSO KEEP BREEZY CONDITIONS IN PLACE OVER
AZ WITH THE STRONGEST WINDS FOCUSED ON THE AFTERNOON HOURS. TEMPS
SHOULD HOVER A FEW DEGREES ABOVE NORMAL AND DRY CONDITIONS WILL
PERSIST. BROST.

&&

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

&&

$$

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