Drought in Arizona, May 1 to 31, 2014

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
925 PM MST WED APR 30 2014

.SYNOPSIS...EXPECT STRONG AND GUSTY EAST TO SOUTHEAST WINDS LATE
TONIGHT AND ESPECIALLY THURSDAY MORNING...THEN WINDS WILL DIMINISH
BY THURSDAY EVENING. OTHERWISE...STRONG HIGH PRESSURE ALOFT OVER THE
WESTERN STATES WILL BRING DRY AND WARMER CONDITIONS INTO THIS
WEEKEND.

&&

.DISCUSSION...MID-LEVEL CYCLONIC CIRCULATION SYSTEM CENTERED OVER
NERN AZ AT THIS TIME WILL MOVE SWD INTO FAR SERN AZ AROUND DAYBREAK
THUR. ANY MEASURABLE PRECIP ASSOCIATED WITH THIS SYSTEM IS FORECAST
TO REMAIN EAST OF SE AZ. HOWEVER...THE MAIN IMPACT FROM THIS SYSTEM
WILL BE GUSTY MOSTLY ELY WINDS LATE TONIGHT INTO EARLY THUR
AFTERNOON. HAVE UPDATED THE OFFICIAL FORECAST THE REST OF TONIGHT
FOR PATCHY BLOWING DUST MAINLY ACROSS THE LOWER ELEVATIONS OF
COCHISE COUNTY. HAVE ALSO INCLUDED SOUTH CENTRAL PINAL COUNTY NW OF
TUCSON IN PATCHY BLOWING DUST MID TO LATE MORNING THUR.

A WIND ADVISORY IS IN EFFECT FROM 8 AM TO NOON MST THUR MAINLY FOR
THE TUCSON METRO AREA. AT THIS TIME...FORECAST CONFIDENCE IS LOW TO
PERHAPS MEDIUM THAT WIND ADVISORY CRITERIA (SUSTAINED SPEEDS OF
GREATER THAN OR EQUAL TO 26 KTS) WILL BE ACHIEVED. HAVE NOTED THAT
THE 01/00Z GFS/NAM MOS GUIDANCE SPEEDS HAVE DROPPED TO BELOW
ADVISORY THRESHOLDS FOR KTUS. THE WINDS WILL START TO DIMINISH THUR
AFTERNOON AND ESPECIALLY BY THUR EVENING AS THE MID-LEVEL TROUGH
AXIS MOVES WELL SE OF THE AREA. HAVE ALSO MAINTAINED THE RED FLAG
WARNING THAT IS IN EFFECT FROM 8 AM TO 1 PM MST THURSDAY.

PLEASE NOTE...THE DUST THROUGHOUT MUCH OF SE AZ IS CAUSING THE
ASOS/S AT KDUG/KOLS/KSAD TO OBSERVE LOWER-LEVEL OVERCAST CEILINGS
WHEN NONE ARE PRESENT. THESE ERRORS WILL LIKELY CONTINUE THE REST OF
TONIGHT...OR SIMILAR TO A BLOWING DUST EVENING THAT OCCURRED MARCH
12-13 EARLIER THIS YEAR.

PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER INFORMATION.

&&

.AVIATION...VALID THRU 02/06Z. THE DUST THROUGHOUT MUCH OF SE AZ IS
CAUSING THE ASOS/S AT KDUG/KOLS/KSAD TO OBSERVE LOWER-LEVEL OVERCAST
CEILINGS WHEN NONE ARE PRESENT. THESE ERRORS WILL LIKELY CONTINUE
THE REST OF TONIGHT...OR SIMILAR TO A BLOWING DUST EVENING THAT
OCCURRED MARCH 12-13 EARLIER THIS YEAR.

AT ANY RATE...AN UPPER LEVEL DISTURBANCE WILL PRODUCE SCATTERED TO
BROKEN CLOUDS MOSTLY ABOVE 8K FT AGL EAST OF A KSAD-KDUG LINE
THURSDAY. OTHERWISE...CLEAR SKIES WITH PATCHY BLDU REDUCING
VISIBILITIES TO 5SM THE REST OF TONIGHT...MOSTLY IN THE VICINITY OF
KDUG/KFHU. SURFACE WIND INTO EARLY THURSDAY AFTERNOON GENERALLY
ELY/SELY 12-18 KTS WITH GUSTS TO 25 KTS. SURFACE WIND THURSDAY
MORNING LOCALLY STRONGER...PARTICULARLY NEAR KTUS...WITH SUSTAINED
SPEEDS AROUND 25 KTS AND GUSTS TO 35 KTS. WINDS ARE EXPECTED TO
DIMINISH TO MOSTLY LESS THAN 12 KTS THURSDAY EVENING. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...RED FLAG CONDITIONS EXPECTED THURSDAY MORNING FOR
PARTS OF ZONE 150 AND 151.  A SYSTEM MOVING INTO NEW MEXICO AND
EASTERN ARIZONA FROM THE NORTH WILL BRING LOCALLY WINDY CONDITIONS
TO PORTIONS OF THE AREA THURSDAY MORNING AND EARLY AFTERNOON.  RED
FLAG CONDITIONS ARE LIKELY THURSDAY MORNING FROM ROUGHLY BENSON WEST
INTO THE EASTERN PART OF ZONE 150.  THIS IS NOT A TYPICAL RED FLAG
EVENT AS THE EAST WINDS WILL START EARLY IN THE MORNING AND WITH THE
VERY DRY AIR MASS IN PLACE...RED FLAG CONDITIONS WILL BEGIN EARLY IN
THE MORNING AS WELL.  THE EAST WIND WILL EASE DURING THE EARLY
AFTERNOON AND DROP BELOW RED FLAG CRITERIA SPEEDS.

BEYOND THAT...DRY WESTERLY FLOW WILL REMAIN ACROSS THE REGION INTO
THE WEEKEND WITH WARMING TEMPERATURES AND MORE TYPICAL WINDS.  EARLY
NEXT WEEK A TROUGH IS EXPECTED TO DEEPEN ALONG THE WEST COAST FOR AN
INCREASE IN SOUTHWEST WINDS AGAIN MONDAY AND TUESDAY.

&&

.PREV DISCUSSION...MODELS INDICATE THAT THE VORT LOBE ASSOCIATED
WITH THE TAIL END OF THE UPPER LOW EXTENDS ACROSS MUCH OF EASTERN
ARIZONA INTO EASTERN UTAH. THIS SYSTEM WILL CONTINUE TO LINGER
ACROSS THE EASTERN PORTION OF THE STATE THROUGH EARLY THURSDAY
BEFORE SLIPPING INTO NORTHEAST SONORA MEXICO LATE THURSDAY
AFTERNOON. AS THIS OCCURS MODELS ARE INDICATING THAT THE LOW TO MID
LEVEL CIRCULATION HAS A LOW OVER NORTHERN SONORA WITH EAST TO
SOUTHEAST FLOW ON THE EAST TO NORTHEAST SIDE OF THIS FEATURE
AFFECTING MUCH OF MY FORECAST AREA. GUIDANCE IS SUGGESTING THAT
THESE EAST WINDS WILL BE THE STRONGEST IN THE TUCSON AREA AND
EXTENDING INTO SMALL PORTIONS OF SOUTHEAST PINAL AND NORTHERN
PORTIONS OF SANTA CRUZ COUNTY. MOS WIND GUIDANCE NUMBERS HAVE BEEN
SUGGESTING THIS SCENARIO FOR DAYS NOW AND THE LATEST NUMBERS SHOW
SUSTAINED 39 MPH WINDS FROM THE NAM AND 31 MPH FROM THE GFS FOR
TUCSON. THE NAM HAS THE WIND PEAKING AT 15Z...WHILE THE GFS HAS IT
PEAKING AT 18Z. THAT SAID...DECIDED TO GO WITH A WIND ADVISORY FOR
MUCH OF EASTERN PIMA COUNTY...A SMALL PART OF PINAL COUNTY AND A
SMALL PART OF NORTHWEST SANTA CRUZ COUNTY. TIMING FOR THE ADVISORY
WILL BE FROM 15Z-19Z (8 AM THROUGH NOON MST). THE CAVEAT TO ALL OF
THIS IS CONFIDENCE IN THE TIMING...SINCE THE MODELS DIFFER. NIGHT
SHIFT WILL HAVE TO REEVALUATE THE SITUATION AS WE GET CLOSER IN TIME
TO THIS EVENT AND IF THE WINDS KICK IN SOONER THAN EXPECTED THEY MAY
HAVE TO ADJUST THE ADVISORY ACCORDINGLY. IN ADDITION TO THE WIND
ADVISORY...WE HAVE GONE WITH A RED FLAG WARNING FOR A SIMILAR AREA.
SEE THE FIRE WEATHER SECTION BELOW FOR DETAILS.

ONCE THE SYSTEM SLIDES SOUTH INTO NORTHERN MEXICO LATE THURSDAY
AFTERNOON THE WINDS WILL DECREASE LATE IN THE AFTERNOON AND INTO THE
EARLY EVENING HOURS. RIDGING WILL DEVELOP BEHIND THIS SYSTEM LATE IN
THE WEEK AND INTO THE WEEKEND FOR A SIGNIFICANT WARMUP IN
TEMPERATURES WITH HIGHS FOR TUCSON EXPECTED TO REACH THE LOWER TO
MID 90S FOR BOTH SATURDAY AND SUNDAY.

A PACIFIC SYSTEM IS EXPECTED TO MOVE INTO WESTERN OR NORTHERN
ARIZONA LATE TUESDAY. TOO EARLY TO TELL IF THIS SYSTEM WILL BRING A
SIGNIFICANT THREAT FOR PRECIPITATION...SO FOR NOW I JUST HAVE SOME
SINGLE DIGIT POPS IN THE GRIDS FROM LATE MONDAY THROUGH
WEDNESDAY...BUT MOSTLY TOO LOW TO MENTION IN THE TEXT PRODUCTS.

HIGH TEMPERATURES ABOVE NORMAL THURSDAY THROUGH MONDAY...WITH THE
WARMEST DAYS OCCURRING SATURDAY AND SUNDAY WHEN HIGHS WILL RANGE
FROM 6 O 9 DEGS ABOVE NORMAL. NEAR NORMAL HIGHS EXPECTED FOR TUESDAY
AND 3 TO 5 DEGS ABOVE NORMAL FOR WEDNESDAY. LOWS GENERALLY ABOVE
NORMAL THROUGH NEXT TUESDAY...WITH THE WARMEST MORNINGS OCCURRING
SUNDAY THROUGH TUESDAY...THEN NEAR NORMAL FOR WEDNESDAY MORNING.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
    RED FLAG WARNING FROM 8 AM TO 1 PM MST THURSDAY FOR AZZ150-151.

    WIND ADVISORY FROM 8 AM TO NOON MST THURSDAY FOR AZZ503>506-
     513-514.

&&

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