Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 201531
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
830 AM MST WED AUG 20 2014

.SYNOPSIS...SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS
WILL CONTINUE THROUGH FRIDAY WITH SOME STORMS PRODUCING HEAVY RAIN
AND GUSTY WINDS.  GRADUAL DRYING IS EXPECTED TO OCCUR THIS WEEKEND
INTO EARLY NEXT WEEK...HOWEVER ENOUGH MOISTURE WILL REMAIN FOR
ISOLATED TO SCATTERED THUNDERSTORMS.  BELOW NORMAL DAYTIME
TEMPERATURES WILL PREVAIL THROUGH FRIDAY FOLLOWED BY A WARMING TREND
THIS WEEKEND.

&&

.DISCUSSION...OTHER THAN A FEW PATCHES OF CLOUDS FAR EASTERN
SECTIONS SKIES ARE CLEAR THIS MORNING.  THE SOUNDING THIS MORNING
SHOWS A SIGNIFICANTLY DRIER MID AND UPPER LEVEL ATMOSPHERE BUT STILL
RATHER UNSTABLE THANKS TO PLENTY OF LOW LEVEL MOISTURE.  THE LOW
LEVEL MOISTURE WILL MIX OUT TO SOME EXTENT BUT SHOULD BE ENOUGH FOR
A FEW THUNDERSTORMS TO DEVELOP OVER THE HIGHER TERRAIN TODAY.  CU
ALREADY SHOWING UP OVER THE HUACHUCA MTNS ALREADY.  ANY STORMS THAT
DEVELOP WILL MOVE OFF TO THE NORTHEAST AND BE YOUR MORE TYPICAL RAIN
AND WIND PRODUCERS RATHER THAN THE HEAVY RAINERS OF LATE.  AS FAR AS
HIGH TEMPERATURES...WILL HAVE RELATIVELY LOW THICKNESS VALUES ACROSS
THE REGION WHICH WILL HOLD HI TEMPS A FEW DEGREES COOLER THAN
NORMAL.  THE WESTERN DESERTS WILL HAVE SIMILAR TEMPS TO YESTERDAY
WHILE AREAS EAST OF TUCSON...WHILE STILL COOLER THAN NORMAL WILL BE
UP TO 10 DEGREES WARMER THAN YESTERDAY THANKS TO MORE SUNSHINE.  NO
UPDATES NEEDED AT THIS TIME.
CERNIGLIA

THE REMAINDER OF THIS SECTION IS FROM THE PRECIOUS DISCUSSION.

TONIGHT...MODEL CROSS SECTIONS INDICATE THAT A BIT MORE MID-LEVEL
MOISTURE WILL BE PULLED FROM THE OUTER EDGE OF TS LOWELL INTO SW AZ
AS THE CLOSED LOW OFF THE SOUTHERN CALIFORNIA COAST SLOWLY MOVES
INLAND OVER SAN DIEGO. COULD SEE A FEW STORMS DEVELOP OVER OUR
WESTERN DESERTS LATE TONIGHT INTO THURSDAY MORNING.

THURSDAY LOOKS RATHER ACTIVE AS THE CLOSED LOW OPENS UP AS IT MOVES
INTO WESTERN ARIZONA. THUS EXPECT A RETURN TO SCATTERED AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS. HIGHS SIMILAR TO WHAT IS
FORECAST FOR TODAY WHICH CONTINUES TO BE BELOW NORMAL.

FRIDAY...TROF AXIS WILL BE MOVING INTO WESTERN NEW MEXICO WITH DRIER
AIR FILTERING ACROSS THE AREA FROM THE WEST. PRECIPITABLE WATER
VALUES ARE PROGGED TO BE LESS THAN ONE INCH IN THE WHITES TO NEAR
1.50" ALONG THE INTNL BORDER. THIS WILL LIMIT THUNDERSTORM ACTIVITY
TO THE MOUNTAINS EAST OF TUCSON AND ALONG THE INTERNATIONAL BORDER
FROM NOGALES EAST. BELOW NORMAL HIGHS CONTINUE FOR ONE MORE DAY.

SATURDAY...THE PACIFIC UPPER TROF THAT KICKS OUR CURRENT LOW THRU
THE STATE ON FRIDAY WILL BE PASSING BY TO OUR NORTH. RATHER DRY
WESTERLY FLOW ALOFT WITH PRECIPITABLE WATER VALUES PROGGED TO RANGE
FROM 0.75"-1.25" DRIEST IN THE WHITES. THUNDERSTORM COVERAGE LESS
THAN FRIDAY BUT PRETTY MUCH IN THE SAME AREAS. WARMER WITH HIGHS
EDGING CLOSER TO NORMAL.

SUNDAY...TROFINESS REMAINING TO OUR NORTH WILL LIMIT ANY
THUNDERSTORM ACTIVITY TO MAINLY THE HIGHER TERRAIN E AND S OF
TUCSON. HIGHS WILL BE AT OR SLIGHTLY ABOVE NORMAL.

MONDAY AND TUESDAY...WILL MAINTAIN LOW GRADE MONSOON FORECAST AS
UPPER LEVEL TROFINESS REMAINS CLOSE TO THE STATE.

DEEPER MOISTURE MAY RETURN TO THE AREA THANKS TO A TROPICAL SYSTEM
MOVING CLOSE ENOUGH TO THE GULF OF CA TO SEND A SURGE OF MOISTURE
NORTH INTO THE STATE. TIME WILL TELL.

&&

.AVIATION...VALID THRU 21/18Z.
EXPECT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS THIS
AFTERNOON...PERSISTING INTO THE EARLY EVENING HOURS.  THESE WILL
MAINLY HUG THE MOUNTAINS WITH THE KOLS AND KDUG TERMINALS MOST
LIKELY TO BE AFFECTED.  KTUS WILL LIKELY NOT HAVE ANY THUNDERSTORM
ACTIVITY TODAY.  MVFR VISIBILITIES AND WIND GUSTS TO 45 KTS WILL
OCCUR WITH THE STRONGER TSRA.  A FEW CLOUDS-SKC CONDITIONS EXPECTED
THRU MID MORNING WEST OF A KOLS TO KCGZ LINE...WITH SCT-BKN CLOUDS
AT 8-14K FT AGL EAST OF THIS LINE.  SCT-BKN CLOUDS AREAWIDE THIS
AFTERNOON AND EVENING AT 6-11K FT AGL...SLOWLY DIMINISHING AFT
21/04Z TONIGHT.  OUTSIDE OF THUNDERSTORM OUTFLOWS...SURFACE WIND
WILL GENERALLY BE LESS THAN 10 KTS.  AVIATION DISCUSSION NOT UPDATED
FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING
THUNDERSTORMS ARE EXPECTED THROUGH EARLY NEXT WEEK.  OVERALL THROUGH
THE WEEKEND THERE WILL BE LESS ACTIVITY THAN WE HAVE HAD OVER THE
LAST WEEK AND THE STORMS WILL NOT BE AS HEAVY WITH RESPECT TO RAIN.
THAT SAID...ANY STRONGER THUNDERSTORMS WILL PRODUCE STRONG...GUSTY
AND ERRATIC WINDS.  OUTSIDE OF THE THUNDERSTORM OUTFLOWS...20-FOOT
WINDS WILL EXHIBIT NORMAL DIURNAL TRENDS AND WILL BE MOSTLY LESS
THAN 15 MPH.

&&

$$

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