Area Forecast Discussion
Issued by NWS Tucson, AZ

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000
FXUS65 KTWC 312139
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
235 PM MST FRI OCT 31 2014

.SYNOPSIS...ANOTHER WARM DAY TO CLOSE OUT OCTOBER WITH SOME
LOCATIONS WITHIN A DEGREE OR TWO OF RECORD HIGHS. A TROUGH WILL
BRING GUSTY WINDS AT TIMES THROUGH THE WEEKEND WITH SIGNIFICANTLY
COOLER AIR EARLY NEXT WEEK. THERE WILL BE A FEW SHOWERS
AROUND...MAINLY ON SUNDAY AFTERNOON. THE COLDEST OVERNIGHT LOWS OF
THE SEASON SO FAR ARE EXPECTED MONDAY NIGHT INTO TUESDAY MORNING.

&&

.DISCUSSION...MID LEVEL RIDGE AXIS NOW EAST OF THE AREA WITH MODEST
LOW LEVEL EASTERLY TO SOUTHEASTERLY GRADIENT BEHIND IT CREATING SOME
GUSTY WINDS TODAY...BUT BELOW ADVISORY LEVELS. THIS FLOW COMBINED
WITH MID LEVEL MOISTURE FROM THE SOUTHWEST HAS PUSHED PRECIPITABLE
WATER VALUES TO AROUND .7 OR SO. MIGHT SEE A FEW SHOWERS MAINLY EAST
OF TUCSON THIS EVENING.

INCREASING SOUTHWESTERLY FLOW AHEAD OF A STRONG WEST COAST TROUGH
SATURDAY. STRONGEST ENERGY AND BEST MOISTURE LIFTING INTO THE
NORTHERN PLAINS BEFORE THE TROUGH AXIS GETS HERE...HOWEVER MODELS
ARE COMING INTO BETTER AGREEMENT BRINGING A DECENT SECONDARY IMPULSE
THROUGH CENTRAL AND NORTHERN ARIZONA SUNDAY. ASSOCIATED COLD FRONT
WILL PUSH ACROSS ARIZONA SUNDAY AS WELL...SAVING OUR PART OF THE
STATE FOR LAST WITH MUCH OF OUR CWA SPENDS MOST OF SUNDAY STILL IN
THE WARM SECTOR. THIS WOULD CREATE THE UNUSUAL SITUATION OF PLACES
LIKE DOUGLAS ENDING UP WARMER THAN YUMA AND PHOENIX.

BEST ENHANCED GRADIENT FOR OUR AREA ON SUNDAY...WITH ADVISORY LEVEL
WINDS POSSIBLE FOR OUR EASTERN AREAS SUNDAY AFTERNOON.

BEST MOISTURE AND DYNAMICS COMING TOGETHER FOR PHOENIX AND FLAGSTAFF
OFFICE AREAS...BUT WE WILL SEE A CHANCE OF SHOWERS AS WELL...MAINLY
SUNDAY AFTERNOON INTO SUNDAY EVENING JUST AHEAD OF AND WITH THE
FRONT. THIS WILL PROBABLY INCLUDE THE FIRST SNOWFALL IN SOME HIGH
MOUNTAIN ZONES WITH 2 INCHES OR SO CURRENTLY FORECAST FOR HANNAGAN
MEADOW IN NORTHERN GREENLEE COUNTY SUNDAY AFTERNOON AND SUNDAY
EVENING AS SNOW LEVELS REMAIN ABOVE 8000 FEET.

MUCH COOLER AIR SETTLING ACROSS ALL OF SOUTHEAST ARIZONA BY MONDAY
WITH THE COLDEST NIGHT OF THE YEAR SO FAR EXPECTED MONDAY NIGHT INTO
TUESDAY. COLDEST EASTERN VALLEY LOCATIONS COULD SEE THE FIRST FREEZE
OF THE SEASON...INCLUDING AREAS AROUND WILLCOX AND SULPHUR SPRINGS
VALLEY AS WELL AS A FEW OTHER SPOTS.

ECMWF CLINGING STUBBORNLY TO A CUT OFF SAGGING BACK INTO NORTHERN
MEXICO JUST SOUTH OF US TUESDAY INTO THURSDAY...WRAPPING THE EDGE OF
SOME TROPICAL MOISTURE UP FROM THE SOUTH AS IT DOES SO. THIS IS NO
LONGER QUITE THE OUTLIER IT WAS BEFORE WITH AN INCREASING NUMBER OF
ECMWF ENSEMBLE MEMBERS SUPPORTING SOMETHING LIKE THIS AS WELL AS
SOMETHING SIMILAR FROM THE NEW CMC. GFS IS EVEN A TAD SLOWER AND
DEEPER THAN IT WAS BEFORE. WE ARE GOING TO MASSAGE A LITTLE MORE OF
THE 12Z ECMWF INTO OUR FORECAST THAN WE DID BEFORE...KEEPING A
SLIGHT CHANCE OF SHOWERS MAINLY EAST AND SOUTHEAST OF TUCSON AND
SLOWING THE REBOUND WARMING TREND WITH THE IDEA THAT THE NEW RIDGE
MAY BE A TAD DIRTIER THAN WE WERE PREVIOUSLY THINKING FOR WEDNESDAY
AND THURSDAY.

&&

.AVIATION...VALID THRU 02/00Z.
VFR CONDITIONS AT ALL TERMINALS.  SCT-BKN MID LEVEL CLOUDS AT 11-15K
FT AGL THRU 01/02...THEN FEW-SCT CLOUDS AT 8-11K FT AGL.  SLIGHT
CHANCE OF -SHRA/-TSRA EAST OF KTUS THRU 01/08Z.  THEN AFT 01/19Z
FEW-SCT CUMULUS 7-10K FT AGL WITH SCT-BKN CIRRUS ABOVE.  SE SURFACE
WIND AT 10-15 KTS EASING AFT 01/01Z BECOMING SLY 10 KTS OR LESS.
SWLY SURFACE WIND INCREASING AFT 01/17Z TO 16-22 KTS WITH GUSTS TO
35 KTS.  AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
CERNIGLIA

&&

.FIRE WEATHER...AN APPROACHING LOW PRESSURE SYSTEM WILL BRING ABOUT
CHANGING CONDITIONS THROUGH THE WEEKEND.  FOR TONIGHT...THERE IS A
SLIGHT CHANCE OF SHOWERS AND T-STORMS EAST OF TUCSON WITH EASING SE
WINDS.  THEN THE APPROACHING LOW WILL GENERATE GUSTY SOUTHWEST TO
WEST WINDS SATURDAY AND SUNDAY AS IT PASSES NORTH OF THE AREA WITH A
DECENT CHANCE OF SHOWERS SUNDAY.  THE WINDS WILL ALSO USHER IN
SIGNIFICANTLY COOLER TEMPERATURES SUNDAY ONWARD WITH THE COOLEST
READINGS EXPECTED MONDAY AND MONDAY NIGHT WITH HIGHS IN THE 60S AND
LOWS IN THE 30S TO MID 40S.  MODEL TRENDS ARE NOW LEANING TOWARD
ANOTHER LOW CENTER BEING IN THE AREA THE MIDDLE OF NEXT WEEK FOR YET
ANOTHER THREAT OF SHOWERS.  CERNIGLIA

&&

.CLIMATE...WARMEST LOW FOR THE DATE AT TUCSON THIS MORNING AT
64...BEATING THE OLD RECORD OF 62 FROM 1987. THE LOW OF 55 AT
DOUGLAS TIES FOR WARMEST.

HALLOWEEN LATELY HAS TURNED OUT TO BE A VERY WARM ONE ACROSS
SOUTHEAST ARIZONA. FOR TUCSON...FROM 1894 TO 2007...THERE WERE ONLY
TWO HALLOWEENS /1916 AND 1999/ WITH HIGHS IN THE LOWER 90S.
INCLUDING TODAY (91 AS OF 2PM)...THIS IS THE THIRD TIME IN THE PAST
SEVEN YEARS /2008 AND 2011/ WITH HALLOWEEN HIGHS IN THE LOWER 90S.

&&

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

&&

$$

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

MEYER/CERNIGLIA





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