Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 061636
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
935 AM MST WED MAY 6 2015

.SYNOPSIS...EXPECT GUSTY WINDS MAINLY DURING THE AFTERNOON HOURS
THROUGH FRIDAY AS A STRONG LOW PRESSURE SYSTEM APPROACHES FROM THE
NORTHWEST. SLIGHTLY WARMER TEMPERATURES WILL OCCUR TODAY FOLLOWED BY
A COOLING TREND THURSDAY THROUGH SATURDAY. THERE IS A SLIGHT CHANCE
OF SHOWERS AND THUNDERSTORMS ACROSS THE WHITE MOUNTAINS SATURDAY AS
THE SYSTEM MOVES NORTH OF THE AREA. DRY CONDITIONS WITH MUCH WARMER
TEMPERATURES WILL THEN PREVAIL EARLY NEXT WEEK.

&&

.DISCUSSION...THE AREA WILL BE IN BETWEEN WEATHER SYSTEMS TODAY AS
ANOTHER ONE DROPS SOUTH ALONG THE INTERIOR WEST COAST INTO SOUTHERN
CALIFORNIA BY TOMORROW MORNING. AS THE SYSTEM APPROACHES...THE WIND
WILL BECOME STRONG AND GUSTY LATER THIS AFTERNOON AND MORE SO ON
THURSDAY. CURRENT FORECAST HANDLES THESE TRENDS WELL...SO NO UPDATES
NECESSARY THIS MORNING. PLEASE REFER TO THE ADDITIONAL SECTIONS FOR
MORE DETAILS.

&&

.AVIATION...VALID THRU 07/18Z.
FEW-SCT CLOUDS AT 8-10K FT AGL WITH SCT-BKN CIRRUS THRU 07/02Z THEN
CLEAR. SFC WINDS BECOMING SW 15 TO 20 KTS GUSTING TO AROUND 30 KTS.
WIND EASING TO SOUTHERLY 5-10 KTS AFTER 07/02Z. AVIATION DISCUSSION
NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...A LOW PRESSURE SYSTEM WILL STRENGTHEN NORTHWEST OF
THE AREA THROUGH FRIDAY RESULTING IN INCREASED SOUTHWEST WINDS EACH
DAY FROM THE LATE MORNING THROUGH EARLY EVENING HOURS. FOR THIS
AFTERNOON AND THURSDAY SUSTAINED 20 FOOT WINDS ARE EXPECTED TO BE
LESS THAN 20 MPH FOR THE MOST PART WITH MIN RH LEVELS ROUGHLY 15-20
PCT. FRIDAY...THE WINDS WILL BE A BIT STRONGER OVER THE SE PART OF
THE AREA WITH SLIGHTLY LOWER MIN RH LEVELS WHICH MAY RESULT IN SHORT
PERIODS WHERE THE WEATHER COMPONENT OF RED FLAG CONDITIONS WILL BE
MET OVER SOUTHERN COCHISE COUNTY...BUT THEN MARGINALLY SO. THAT
ALONG WITH MODERATE FUEL CONDITIONS WOULD PRODUCE MARGINAL...SPOTTY
AND SHORT DURATION RED FLAG CONDITIONS OVERALL. THUS...THERE ARE NO
HEADLINES PLANNED AT THIS TIME.

OTHER THAN THAT...A FEW SHOWERS AND THUNDERSTORMS MAY OCCUR ACROSS
THE WHITE MOUNTAINS SATURDAY AS THE LOW PRESSURE SYSTEM MOVES NORTH
OF THE AREA. EXPECT LESS WIND THIS WEEKEND ALTHOUGH SOME AFTERNOON
GUSTINESS WILL OCCUR DUE TO DAYTIME HEATING.

&&

.PREV DISCUSSION...A LONGWAVE TROUGH CONTINUES OVER THE WRN CONUS
EARLY THIS MORNING...WITH A 548 DM LOW CENTERED OVER WASHINGTON
STATE... AND A SHORTWAVE TROUGH AXIS NEAR THE SRN CALIFORNIA/NRN
BAJA CALIFORNIA COASTS. THE SHORTWAVE TROUGH WILL MOVE NEWD AND
BRING MID AND HIGH-LEVEL CLOUDS SUFFICIENT FOR MOSTLY SUNNY TO
PARTLY CLOUDY SKIES TODAY. CLOUDS WILL DECREASE FROM SW-NE THIS
EVENING FOLLOWED BY CLEAR SKIES OR MOSTLY CLEAR SKIES EARLY THUR
MORNING.

THE MID-LEVEL PRESSURE GRADIENT WILL TIGHTEN TODAY IN RESPONSE TO
THE DEEPENING LOW PRESSURE SYSTEM OVER THE PACIFIC NW. 06/00Z NAM/
GFS/ECMWF/CMC WERE IN EXCELLENT AGREEMENT WITH DIGGING THE COLD CORE
LOW SWD INTO CENTRAL CALIFORNIA MIDDAY THUR...THEN SLOWLY MOVING THE
UPPER LOW EWD INTO SRN NEVADA BY MIDDAY FRI. DRY CONDITIONS WILL
PREVAIL THUR-FRI AHEAD OF THIS SYSTEM. HOWEVER...A TIGHT MID-LEVEL
GRADIENT WILL MAINTAIN BREEZY TO WINDY CONDITIONS THUR-FRI...
ESPECIALLY DURING THE AFTERNOON HOURS.

THE UPPER LOW WILL BEGIN TO FILL FRI EVENING...THEN MOVE EWD TOWARD
THE FOUR CORNERS REGION SAT AFTERNOON. DEEPER MOISTURE ASSOCIATED
WITH THIS SYSTEM IS PROGGED TO REMAIN MAINLY NORTH OF THIS FORECAST
AREA. HOWEVER...THERE WILL BE ENOUGH MOISTURE FOR A SLIGHT CHANCE OF
SHOWERS SAT MORNING ACROSS THE WHITE MOUNTAINS. THE AIRMASS SHOULD
BE SUFFICIENTLY UNSTABLE TO SUPPORT AT LEAST A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE WHITE MOUNTAINS SAT AFTERNOON
AND SAT EVENING.

DRY CONDITIONS WILL RETURN AREA-WIDE BY EARLY SUN MORNING AS THE
UPPER LOW MOVES INTO ERN COLORADO. EXPECT LESS WIND THIS WEEKEND...
ALTHOUGH SOME AFTERNOON GUSTS WILL OCCUR DUE TO DAYTIME HEATING. DRY
CONDITIONS WILL PREVAIL MON-TUE AS A SHORTWAVE RIDGE INITIALLY OVER
THE SWRN CONUS MOVES WELL EASTWARD TUE IN ADVANCE OF THE NEXT STRONG
UPPER LOW CENTERED OVER NRN CALIFORNIA.

THEREAFTER...HAVE NOTED THAT THE 06/00Z ECMWF REMAINED VERY SIMILAR
VERSUS SEVERAL PREVIOUS ECMWF SOLUTIONS WITH BRINGING FAIRLY DEEP
MOISTURE AND POTENTIALLY WIDESPREAD RAINFALL TO SE ARIZONA NEXT WED.
MEANWHILE...THE GFS KEPT THE DEEPER MOISTURE JUST EAST OF THIS
FORECAST AREA ACROSS THE SRN ROCKIES. WILL DEFER THE PROSPECT FOR
PRECIP NEXT WED TO THE DAY SHIFT SINCE THIS PERIOD IS BEYOND THE
SCOPE OF THIS FORECAST PACKAGE.

HIGH TEMPS THIS AFTERNOON WILL BE SEVERAL DEGS WARMER VERSUS TEMPS
ACHIEVED TUE FOR MOST LOCALES...THEN A COOLING TREND WILL OCCUR THUR-
SAT. MARKEDLY WARMER DAYTIME TEMPS WILL PREVAIL EARLY NEXT WEEK.

&&

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

&&

$$

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