Area Forecast Discussion
Issued by NWS Phoenix, AZ

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000
FXUS65 KPSR 012017
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
117 PM MST WED APR 1 2015

.SYNOPSIS...
A DRY WEATHER SYSTEM WILL MOVE INTO THE REGION FROM THE GREAT BASIN
LATE TONIGHT THROUGH FRIDAY...USHERING IN COOLER TEMPERATURES AND
INCREASING WINDS. DRY CONDITIONS WILL REMAIN THROUGH THE WEEKEND
WITH CONTINUED ABOVE NORMAL TEMPERATURES WITH DAYTIME HIGHS IN THE
UPPER 80S TO LOW 90S. AN ACTIVE UPPER LEVEL PATTERN WILL LINGER OVER
THE WEST INTO NEXT WEEK...RESULTING IN NEAR OR POSSIBLY EVEN BELOW
NORMAL TEMPERATURES FOR OUR AFTERNOONS AND MILD MORNINGS.

&&

.DISCUSSION...
ZONAL FLOW REMAINS IN PLACE ACROSS THE REGION THIS AFTERNOON...AS A
WEAK UPSTREAM SHORTWAVE TROUGH MOVES THROUGH NORTHERN CALIFORNIA. AS
HEIGHTS ARE SLIGHTLY LOWER TODAY COMPARED TO YESTERDAY...TEMPERATURES
ARE ALSO RUNNING A FEW DEGREES COOLER THAN THIS TIME TUESDAY
AFTERNOON. MOST DESERT LOCALES WERE GENERALLY IN THE MID/UPPER 80S AS
OF 20Z...STILL ABOVE NORMAL FOR EARLY APRIL.

FORECAST CONCERNS IN THE SHORT TERM ARE PRIMARILY FOCUSED ON THE
PASSAGE OF THE UPSTREAM TROUGH ON THURSDAY. THE SYSTEM IS MOISTURE
STARVED AND PRECIP CHANCES ARE NIL...HOWEVER IN TYPICAL SPRINGTIME
FASHION THE TROUGH WILL SWEEP THROUGH AND USHER IN LOWER DEWPOINTS
AND INCREASED WINDS. GRADIENTS WILL BE TIGHTEST ACROSS
NORTHERN/EASTERN ARIZONA AND THESE AREAS WILL LIKELY SEE THE
STRONGEST WINDS...SIMILARLY STRONG DRY ADVECTION DOWN THE COLORADO
RIVER WILL ALSO PRODUCE A BRIEF PERIOD OF AFTERNOON BREEZINESS ON
THURSDAY. THAT BEING SAID...IT STILL APPEARS THAT CRITICAL FIRE
WEATHER THRESHOLDS WILL NOT BE REALIZED OVER A PROLONGED PERIOD OF
TIME AND A WIDESPREAD AREA WITH THE PASSAGE OF THIS EVENT...AND NO
FIRE WEATHER HEADLINES SEEM WARRANTED AT THIS TIME. THE TROUGH WILL
USHER IN SLIGHTLY COOLER TEMPERATURES ALTHOUGH HIGHS THURSDAY AND
FRIDAY /WHILE COOLER/ WILL REMAIN ABOVE NORMAL.

FORECAST SOLNS IN THE EXTENDED REMAIN IN FAIRLY GOOD AGREEMENT
THROUGH ABOUT THE MIDDAY MONDAY TIME FRAME. LONGWAVE TROUGHING HOLDS
OVER MUCH OF THE WEST WITH EMBEDDED SHORTWAVE PASSING THROUGH THE
REGION TO OUR NORTH. AFTER MONDAY...A MORE ORGANIZED PACIFIC LOW IS
PROGGED TO DEVELOP OVER THE PACIFIC NW AND THEN EXPAND DOWN THE WEST
COAST. OUT OF THE 00Z OPERATIONS GUIDANCE...THE ECMWF SOLN IS THE
COLDEST AND DEEPEST SWEEPING THE SYSTEM THROUGH AZ AS A CUT-OFF LOW.
THE GFS/GEM SOLNS FAVOR A MORE OPEN WAVE WITH A LESSER SOUTHERN
EXTENT. ENSEMBLE SPREAD REMAINS HIGH...PARTICULARLY OVER THE
NORTHEAST PACIFIC AND OVER THE PACIFIC NW WITH THE GENESIS OF THIS
SYSTEM. TAKING A MEDIAN VALUE FORECAST OF ALL AVAILABLE TEMPERATURE
GUIDANCE ALONG WITH A HEAVY BLEND OF CONSENSUS GUIDANCE RESULTS IN
THE POSSIBILITY OF BELOW NORMAL TEMPERATURES DURING THE MIDDLE OF
NEXT WEEK. NORMALS FOR THIS PERIOD IN PHOENIX AND YUMA ARE 82/83 AND
84/85 DEGREES RESPECTIVELY. CONFIDENCE IS MARGINAL IN THESE FORECAST
VALUES AND EVEN LOWER IN THE TIMING AND MOVEMENT OF THE WEATHER
SYSTEM RESPONSIBLE FOR THE COOL DOWN. DESPITE THE DEPTH
DIFFERENCES...ALL SOLNS ATTM INDICATE THIS SYSTEMS WILL GNLY BE ON
THE DRIER SIDE. SOME MOISTURE MAY WORK INTO EASTERN AZ/MOGOLLON RIM
AND COULD RESULT IN SOME PRECIP ACTIVITY. SLIGHT BLEND OF (ABOUT 5
PERCENT OVER EACH 12 HR PERIOD) WAS WORKED INTO THE EXTENDED POP
GRIDS. RESULTING POPS DO NOT GENERATE ANY SENSIBLE WEATHER...BUT AT
LEAST A TREND WAS INTRODUCED FOR THE MIDDLE PARTS OF NEXT WEEK.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND
KSDL...AND SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL
AND KBLH...
A DRY WEATHER DISTURBANCE WILL APPROACH NORTHERN ARIZONA TODAY
RESULTING IN GUSTY AFTERNOON/EARLY EVENING WEST WINDS OVER MOST OF
SOUTHWEST AND SOUTH CENTRAL ARIZONA. THROUGH 18Z WED...CLEAR SKIES.
LIGHT AND VARIABLE WIND UNDER 8 KNOTS. FROM 18Z WED THROUGH 03Z
THU...INCREASING AFTERNOON WEST WIND 10 TO 20 KNOTS...STRONGEST
AROUND 23Z. CLEAR SKIES.

A WEAK WEATHER DISTURBANCE PASSING TO THE NORTH WILL CONTINUE TO
PRODUCE GUSTY WESTERLY WINDS AT MOST...OR ALL OF THE TAF SITES
THROUGH THE EVENING HOURS BEFORE DIMINISHING LATER TONIGHT.
ANOTHER..STRONGER WEATHER SYSTEM IS EXPECTED TO BRING ANOTHER PERIOD
OF GUSTY WESTERLY WINDS TO THE PHX TAF SITES...NORTHERLY WINDS TO
KBLH...AND NORTHWESTERLY WINDS TO KIPL ON THURSDAY AFTERNOON...WITH
GUSTS RISING INTO THE 20-25KT RANGE DURING THE LATE AFTERNOON. A
VERY DRY AIRMASS WILL KEEP SKIES MAINLY CLEAR THROUGH THE TAF
PERIOD...EXCEPT FOR PERIODS OF FEW-SCT HIGH CIRRUS LAYERS PASSING
OVERHEAD FROM TIME-TO-TIME.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...A WEAK HIGH PRESSURE SYSTEM WILL BUILD OVER
THE REGION FRIDAY AND SATURDAY FOR MUCH LIGHTER AFTERNOON WIND...
FOLLOWED BY MORE WEATHER DISTURBANCES AND GUSTY AFTERNOON WEST WIND
15 TO 30 MPH SUNDAY...MONDAY...AND TUESDAY. NO PRECIPITATION IS
EXPECTED THIS PERIOD. MINIMUM RELATIVE HUMIDITIES WILL RANGE FROM 5
TO 10 PERCENT. FAIR RECOVERY IS EXPECTED OVERNIGHT. MARGINAL FIRE
WEATHER CONDITIONS ARE EXPECTED SUNDAY AND MONDAY AFTERNOONS DUE TO
WIND AND LOW HUMIDITY.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&

$$

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...LEINS/NOLTE
AVIATION....PERCHA
FIRE WEATHER...VASQUEZ


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