Area Forecast Discussion
Issued by NWS Tucson, AZ

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000
FXUS65 KTWC 190407
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
905 PM MST SAT APR 18 2015

.SYNOPSIS...DRY CONDITIONS WITH ABOVE NORMAL DAYTIME TEMPERATURES
WILL PREVAIL INTO THE MIDDLE OF THE UPCOMING WEEK. GUSTY WINDS
SHOULD RETURN WEDNESDAY AND CONTINUE INTO THURSDAY AS A LOW PRESSURE
SYSTEM MOVES TOWARD THE AREA FROM THE WEST. COOLER TEMPERATURES WILL
ALSO OCCUR THURSDAY...AND THERE IS A SLIGHT CHANCE OF SHOWERS
THURSDAY AND THURSDAY NIGHT...MAINLY NORTH OF TUCSON.

&&

.DISCUSSION...WIND SPEEDS CONTINUED TO DIMINISH LATE THIS EVENING.
THE RED FLAG WARNING POSTED EARLIER WAS ALLOWED TO EXPIRE ON TIME.
OTHERWISE...SATELLITE IMAGERY WAS SHOWING MOSTLY CLEAR SKIES ACROSS
THE AREA LATE THIS EVENING. CURRENT FORECAST HANDLED THESE CONDTIONS
WELL...SO NO UPDATES NECESSARY THIS EVENING. PLEASE REFER TO THE
ADDITIONAL SECTIONS FOR MORE DETAILS.

&&

.AVIATION...VALID THRU 20/06Z.
SCT CLOUDS AROUND 6-10K FT AGL OVER THE WHITE MTNS AGAIN SUNDAY
AFTERNOON. OTHERWISE...CLEAR SKIES THROUGH SUNDAY. SURFACE WIND
ELSEWHERE WILL GENERALLY BE LESS THAN 10 KTS. THEN A NEAR REPEAT IN
THE WIND SUNDAY AFTERNOON WITH NW WINDS 8-15 KTS DEVELOPING AFT
19/20Z. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...EXPECT WARM AND DRY CONDITIONS THROUGH WEDNESDAY AS
AN UPPER LOW DEVELOPS OFF THE SOUTHERN CALIFORNIA COAST. THIS LOW
WILL BRING INCREASINGLY STRONG SW WINDS TO THE AREA MONDAY THROUGH
WEDNESDAY.

THE UPPER LOW WILL MOVE ACROSS THE AREA THURSDAY INTO EARLY FRIDAY
BRINGING A CHANCE OF SHOWERS...COOLER TEMPERATURES AND GUSTY SW
WINDS. ELEVATED RH CONDITIONS ARE EXPECTED TO PREVENT RED FLAG
CONDITIONS FROM OCCURRING DURING THIS PERIOD DESPITE THE STRONG
WINDS.

&&

.PREV DISCUSSION...EXPECT CLEAR SKIES MOST SECTIONS TONIGHT EXCEPT
FOR MOSTLY CLEAR SKIES ACROSS THE WHITE MOUNTAINS. A SIMILAR
SCENARIO IS ON TAP SUNDAY WITH ABUNDANT SUNSHINE FOR MOST OF THE
AREA. MOSTLY SUNNY SKIES TO PARTLY CLOUDY SKIES WILL OCCUR AGAIN
ACROSS THE WHITE MOUNTAINS. ANY MEASURABLE RAINFALL SHOULD REMAIN
JUST NORTH OF THIS FORECAST AREA.

A SHORTWAVE RIDGE AXIS OVER THE AREA MON WILL MOVE EWD INTO THE SRN
ROCKIES TUE AHEAD OF A DEVELOPING UPPER TROUGH EXTENDING FROM SRN
CALIFORNIA/NRN BAJA CALIFORNIA WWD TO AROUND 130W. FLOW ALOFT WILL
BECOME INCREASINGLY SWLY TUE AND BECOME MORE PRONOUNCED WED AS THE
UPPER TROUGH CONTINUES TO DEEPEN WEST OF THE AREA. PRECIP-FREE
CONDITIONS WILL OCCUR TUE INTO WED NIGHT.

THEREAFTER...THE 18/12Z GFS/ECMWF WERE FAIRLY SIMILAR WITH DEPICTING
A 558-559 DM LOW TO BE CENTERED OVER FAR SWRN ARIZONA/EXTREME NWRN
SONORA MIDDAY THUR. THESE SOLUTIONS DEPICTED SIMILAR MOISTURE FIELDS
THUR AFTERNOON...WITH THE BULK OF MEASURABLE PRECIP TO OCCUR MAINLY
NORTH OF THIS FORECAST AREA ACROSS CENTRAL/NRN ARIZONA. HAVE NOTED
THAT THE 18/12Z CMC WAS CONSIDERABLY DRIER VERSUS THE GFS/ECMWF. THE
UPPER LOW IS THEN PROGGED TO FILL AND LIFT RAPIDLY NEWD INTO NRN NEW
MEXICO BY EARLY FRI MORNING.

BASED ON THESE SOLUTIONS...HAVE ONLY MADE VERY MINOR MODIFICATIONS
TO THE INHERITED GRIDDED DATA POP FIELDS. THUS...THERE IS A SLIGHT
CHANCE OF SHOWERS THUR GENERALLY NW OF A HANNAGAN MEADOW-TUCSON-SELLS
LINE. A SLIGHT CHANCE OF SHOWERS EXISTS ACROSS MUCH OF THE AREA THUR
NIGHT. SOME VERY LIGHT SNOW ACCUMULATIONS MAY OCCUR BY DAYBREAK FRI
ABOVE 8000 FEET. HAVE MAINTAINED A SLIGHT CHANCE OF SHOWERS FRI
ACROSS THE WHITE MOUNTAINS AND ACROSS THE GALIURO/PINALENO MOUNTAINS
OF GRAHAM COUNTY. OTHERWISE...DRY CONDITIONS SHOULD OCCUR FRI BEHIND
THE DEPARTING SYSTEM.

THEREAFTER...THERE WERE CONSIDERABLE DIFFERENCES BETWEEN THE GFS/
ECMWF REGARDING THE NEXT SHORTWAVE TROUGH/UPPER LOW WEST OF THE AREA
FRI NIGHT-SAT. THE ECMWF DEPICTED A DEEPER UPPER TROUGH TO BE OVER
SRN CALIFORNIA MIDDAY SAT. MEANWHILE...THE GFS DEPICTED A MUCH
WEAKER SYSTEM TO BE WELL SW OF THE SRN CALIFORNIA COAST. EITHER
SOLUTION MAINTAINED DRY CONDITIONS NEXT FRI NIGHT-SAT.

EXPECT THE WARMING TREND TO CONTINUE SUN-MON...WITH DAYTIME TEMPS
MON (THE WARMEST DAY) TO AVERAGE NEARLY 2-5 DEGS F ABOVE NORMAL. A
COOLING TREND WILL THEN OCCUR TUE-THUR...WITH HIGH TEMPS THUR TO BE
ABOUT 3-7 DEGS F BELOW NORMAL. EXPECT WARMER TEMPS TO RETURN SAT.

&&

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

&&

$$

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

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







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