Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 210954
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
254 AM MST MON APR 21 2014

.SYNOPSIS...A STRONG WARMING TREND PUSHES TEMPERATURES BACK INTO THE
90S FROM TUCSON WESTWARD TODAY AND TUESDAY. BREEZY TO LOCALLY WINDY
CONDITIONS ARE EXPECTED TUESDAY AND ESPECIALLY WEDNESDAY AS A SYSTEM
BRUSHES BY NORTH OF THE AREA.

&&

.DISCUSSION...WATER VAPOR IMAGERY SHOWS RIDGING BUILDING IN FROM THE
WEST. ENOUGH RESIDUAL MOISTURE IN PLACE TO JUSTIFY KEEPING A SLIGHT
CHANCE POPS IN FOR EXTREME NORTHERN PART OF GREENLEE COUNTY FOR THIS
AFTERNOON. OTHERWISE...DRY ELSEWHERE. AS THE RIDGE BUILDS IN
OVERHEAD TODAY AND THEN SHIFTS EAST ON TUESDAY...EXPECT ABOVE NORMAL
HIGH TEMPERATURES FOR TODAY AND TUESDAY WITH HIGHS IN THE LOWER 90S
FOR THE CENTRAL AND WESTERN DESERTS.

MODELS INDICATE THAT BY LATE TUESDAY THE TAIL END OF A PACIFIC
SYSTEM WILL BEGIN TO MOVE THROUGH THE GREAT BASIN AND THEN THROUGH
NORTHERN ARIZONA AND NEW MEXICO ON WEDNESDAY. THIS WILL USHER IN
STRONGER WINDS BOTH TUESDAY AND WEDNESDAY...ALBEIT THE STRONGEST
WINDS WILL OCCUR WEDNESDAY AFTERNOON AND EARLY EVENING. THIS WILL
RESULT IN SOME FIRE WEATHER CONCERNS FOR WEDNESDAY (SEE THE FIRE
WEATHER SECTION BELOW).

ONCE THIS SYSTEM EXITS THE REGION LATE WEDNESDAY...NEARLY ZONAL FLOW
WILL DEVELOP OVER THE DESERT SOUTHWEST THROUGH AROUND EARLY FRIDAY
BEFORE ANOTHER PACIFIC SYSTEM BEGINS TO APPROACH THE WEST COAST ON
FRIDAY. BY EARLY TO MIDDAY SATURDAY THIS SYSTEM WILL BE ENTERING
WESTERN OR NORTHWESTERN ARIZONA AND IT COULD BRING A SMALL THREAT
FOR MOUNTAIN SHOWERS OVER THE WEEKEND. FOR NOW I JUST SHOW SINGLE
DIGIT POPS...WHICH WILL NOT BE ENOUGH TO MENTION IN THE TEXT
PRODUCTS. MORE SIGNIFICANTLY THERE WILL BE AN INCREASE ONCE AGAIN IN
THE WINDS ON SATURDAY FOR POTENTIAL FIRE WEATHER CONCERNS WITH WIND
SPEEDS IN THE BREEZY TO LOCALLY WINDY RANGE FOR SATURDAY.

HIGH TEMPERATURES WILL RANGE FROM 7 TO 10 DEGS ABOVE NORMAL TODAY
AND TUESDAY...THEN 2 TO 4 DEGS ABOVE NORMAL WEDNESDAY THROUGH
FRIDAY. FOR NEXT WEEKEND...HIGHS WILL BE AROUND 2 TO 4 DEGS BELOW
NORMAL. LOWS WILL BE 8 TO 10 DEGS ABOVE NORMAL TUESDAY AND WEDNESDAY
MORNINGS...THEN 2 TO 4 DEGS ABOVE NORMAL THURSDAY THROUGH SATURDAY
AND NEAR NORMAL FOR SUNDAY MORNING.  MOLLERE

&&

.AVIATION...VALID THRU 22/12Z.  CLEAR SKIES WITH EXCEPTION OF
FEW-SCT CUMULUS OVER THE MOUNTAINS 21/19Z THRU 22/01Z.  NORMAL
DIURNAL WIND TRENDS...GENERALLY BELOW 10KTS EXCEPT GUSTY DURING
AFTERNOON HOURS DUE TO SURFACE HEATING AND TERRAIN EFFECTS.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.  CERNIGLIA

&&

.FIRE WEATHER...DRY AND WARMER CONDITIONS EXPECTED THROUGH AT LEAST
FRIDAY.  AN UPPER LEVEL TROUGH MOVING ACROSS THE WESTERN US MID WEEK
WILL GENERATE SOME WEST TO SOUTHWEST WINDS ACROSS THE AREA.  MODELS
OF LATE HAVE BEEN A TOUCH WEAKER THAN EARLIER THIS PAST WEEKEND
HOWEVER THEY ARE STILL STRONG ENOUGH TO BRING A THREAT OF CRITICAL
FIRE WEATHER CONDITIONS...ESPECIALLY EAST OF TUCSON.

SOUTHWEST WINDS WILL INCREASE TUESDAY AFTERNOON WITH SUSTAINED 20 FT
WINDS GENERALLY PEAKING IN THE 15 TO 20 MPH RANGE LATE IN THE DAY
ACROSS MOST OF THE FORECAST AREA...JUST SHY OF RED FLAG CRITERIA.
MINIMUM RH LEVELS WILL GENERALLY BE IN THE 10-15% RANGE WITH
SLIGHTLY HIGHER VALUES IN THE MOUNTAINS AND A FEW SINGLE DIGITS IN
THE VALLEYS.

THE TROUGH AXIS WILL PASS ACROSS THE AREA WEDNESDAY...A BIT QUICKER
THAN EARLIER PROGGED...SHIFTING THE FOCUS OF THE STRONGEST WIND OVER
THE EASTERN THIRD OF THE AREA.  MINIMUM RH LEVELS WILL BE SIMILAR TO
TUESDAY WITH GUIDANCE CONTINUING TO INDICATE RED FLAG WIND SPEEDS
PRIMARILY ACROSS ZONE 152 (MINUS THE WESTERN THIRD OF GRAHAM COUNTY)
AND THE SOUTHERN...LOWER ELEVATIONS OF ZONES 153.  BASED ON THAT
DECIDED TO ISSUE A FIRE WEATHER WATCH FOR THAT AREA FOR THE
AFTERNOON INTO THE EARLY EVENING HOURS OF WEDNESDAY.

THURSDAY WILL BE A BREEZY DAY EAST OF A TUCSON/NOGALES LINE BUT IT
WILL REMAIN BELOW WARNING CRITERIA.

MODELS CONTINUE TO INDICATE THAT A STRONGER TROUGH WILL MOVE ACROSS
THE AREA NEXT WEEKEND.  CRITICAL FIRE WEATHER CONDITIONS OVER A
LARGER AREA ARE POSSIBLE AGAIN SATURDAY AFTERNOON.  CERNIGLIA


&&

.TWC WATCHES/WARNINGS/ADVISORIES...FIRE WEATHER WATCH FROM WEDNESDAY
       AFTERNOON THROUGH WEDNESDAY EVENING FOR AZZ152-153.

&&

$$

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