419 
FXUS65 KPSR 160327
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
825 PM MST SAT MAR 15 2014

.SYNOPSIS...
HIGH PRESSURE OVER THE EASTERN PACIFIC WILL KEEP THE MAIN STORM 
TRACK WELL TO OUR NORTH...OVER THE PACIFIC NORTHWEST AND NORTHERN 
ROCKIES THROUGH AT LEAST THE END OF NEXT WEEK. DRY WEATHER WITH 
MOSTLY CLEAR SKIES AND ABOVE NORMAL TEMPERATURES WILL PREVAIL OVER 
THE DESERT SOUTHWEST THROUGH THE ENTIRE PERIOD.

&&

.DISCUSSION...
A CONGLOMERATE OF COMPACT VORTICITY CENTERS CONTINUE TO ROTATE ABOUT 
AN OVERALL CIRCULATION CENTER COVERING NEW MEXICO AND WEST TEXAS 
THIS EVENING. DOMINANT UPSTREAM RIDGING HAS FORCED STRONG SFC 
PRESSURE RISES OVER THE GREAT BASIN...IN ADDITION TO TIGHT 
UNIDIRECTIONAL NORTHERLY FLOW STREAMING INTO THE FORECAST AREA. 
REGIONAL VAD WIND PROFILES SAMPLE NLY 30KT WINDS AT 2K-3K FT 
INCREASING TO 50+KT ABOVE 9K FT. ALTHOUGH THE AREA IS WELL BEYOND 
PEAK HEATING AND SUNSET TIME...THE BOUNDARY LAYER HAS NOT YET FULLY 
DECOUPLED...OWING TO PROBABLE MOUNTAIN WAVE ACTIVITY (AS EVIDENCED 
BY SEVERAL PIREPS AROUND THE PHX METRO OF MOD-SEV TURBULENCE EARLIER 
IN THE EVENING). 

VALLEY LOCATIONS SHOULD EVENTUALLY LOSE GUSTINESS LATER THIS 
EVENING...THOUGH THE PROCESS MAY BE PROLONGED/DELAYED GIVEN THE 
STEEP LAPSE RATES AND SUBSIDENT FLOW PATTERN THROUGH THE ATMOSPHERIC 
COLUMN. SOME LOCATIONS IMMEDIATELY DOWNSTREAM OF TERRAIN RIDGES MAY 
NEVER DECOUPLE...AND IT WOULD NOT BE COMPLETELY UNEXPECTED TO SEE 
PERIODIC SPORADIC GUSTS WORK TOWARDS LOWER ELEVATIONS TONIGHT. GIVEN 
THE CURRENT CONDITIONS...HOURLY TEMPERATURES WERE OBVIOUSLY NOT 
FALLING MUCH AT ALL AND RAISED FORECAST LOWS ACROSS THE BOARD (IN 
SOME PLACES NEAR RIDGES VERY SUBSTANTIALLY...AND ADMITTEDLY POSSIBLY 
NOT NEARLY ENOUGH). SOME ADJUSTMENTS WERE ALSO MADE TO WINDS AND 
DEWPOINTS BASED ON RECENT TRENDS.

&&

.PREVIOUS DISCUSSION...
/255 PM MST SAT MAR 15 2014/
THE MAIN WEATHER ISSUE THROUGH TONIGHT CONTINUES TO BE THE 
DEVELOPMENT OF STRONG WINDS ACROSS PORTIONS OF OUR CWA...WITH BREEZY 
CONDITIONS ELSEWHERE. A RATHER STRONG...BUT QUITE DRY SHORTWAVE CAN 
BE SEEN ON THE LATEST IR IMAGERY JUST ENTERING EXTREME NE AZ AS IT 
ROTATES SOUTHWARD AROUND AN UPPER LOW CENTER THAT IS MOVING INTO 
NORTH-CENTRAL NM. THIS SHORTWAVE IS EXPECTED TO SHARPLY INCREASE THE 
WINDS OVER THE HIGHER TERRAIN OF SOUTHERN GILA COUNTY AS IT MOVES 
SOUTHWARD OVER THE REGION THIS EVENING. LATEST NAM...AND GFS 
FORECAST SOUNDINGS FOR THE HILLTOP AREA ARE SHOWING 700MB WINDS 
EXCEEDING 50 KNOTS FOR ABOUT A 9-12 HOUR PERIOD THIS EVENING AND 
TONIGHT...WHICH IS EXPECTED TO RESULT IN A SHORT PERIOD OF NORTHERLY 
SFC WINDS LOCALLY EXCEEDING 30 MPH...WITH GUSTS IN EXCESS OF 40 MPH 
LIKELY AT THE MOST FAVORED LOCATIONS/RIDGETOPS OF SOUTHERN GILA 
COUNTY. THE LIMITING FACTOR TO THE STRENGTH AND DURATION OF THE 
WINDS IS THE FACT THAT THE STRONGEST WINDS ALOFT DO NOT MOVE INTO 
THE REGION UNTIL NIGHTFALL...WHICH WILL LIKELY INHIBIT THE MOMENTUM 
TRANSFER OF THE STRONGER WINDS ALOFT DOWN TO THE SFC. BREEZY TO 
WINDY CONDITIONS ARE EXPECTED TO DEVELOP THROUGH THIS EVENING 
ELSEWHERE ACROSS SOUTH-CENTRAL AND SOUTHWEST ARIZONA...WITH 
SUSTAINED WINDS OF 20-25 MPH...WITH GUSTS TO 35 MPH LIKELY AT MANY 
LOCATIONS.

LATEST GLOBAL AND MESOSCALE MODELS ARE IN GOOD AGREEMENT THAT THE 
WINDS WILL RAPIDLY DIMINISH IN MOST AREAS LATER TONIGHT AS THE 
UPPER-LEVEL SHORTWAVE MOVES RAPIDLY OFF TO THE SOUTH...INTO NORTHERN 
MEXICO...AND WINDS ALOFT DROP OFF SMARTLY. THE ONLY EXCEPTION IS 
OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA...WHERE ITS IS 
LIKELY THAT THERE WILL BE ANOTHER PERIOD OF ELEVATED WINDS SPEEDS 
(FROM THE NE) LATER TONIGHT AND EARLY SUN AS SFC HIGH PRESSURE 
BRIEFLY BUILDS OVER NE AZ.

LATEST GFS...AND EURO MODELS CONTINUE THE IDEA OF BRIEFLY BUILDING 
STRONG RIDGING INLAND OVER OUR CWA LATE SUNDAY INTO MONDAY. THIS 
RIDGING IS EXPECTED TO ALLOW TEMPERATURES TO WARM INTO THE MID 80S 
ACROSS SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND TO NEAR 90 ACROSS 
THE LOWER COLORADO RIVER VALLEY AND SOUTHEAST CA ON MONDAY. AFTER 
MONDAY...MODELS THEN WEAKEN THE RIDGING SOMEWHAT AS THE FLOW ALOFT 
BECOMES NORTHWESTERLY...AS A SERIES OF UPPER-LEVEL TROUGHS DROP 
SOUTHEASTWARD FROM THE PACIFIC NORTHWEST INTO THE NORTHERN/CENTRAL 
ROCKIES THROUGH THE REMAINDER OF NEXT WEEK. THE ONLY REAL IMPACT 
FROM THIS PATTERN CHANGE WILL BE TO JUST LOWER TEMPERATURES A 
BIT...BACK INTO THE UPPER 70S AND LOW 80S ACROSS THE LOWER 
DESERTS...WHILE STILL KEEPING DRY CONDITIONS AND MOSTLY CLEAR SKIES 
IN PLACE ACROSS THE REGION THROUGH AT LEAST THE END OF THE WEEK.    

&&

.AVIATION... 
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
CLEAR SKIES WILL PERSIST THROUGH SUNDAY EVENING WITH WINDS THE 
PRIMARY AVIATION CONCERN. NNW SURFACE WINDS 10-20KT WITH HIGHER 
GUSTS WILL CONTINUE THIS EVENING...AND GRADUALLY TRANSITIONING TO 
NE HEADINGS LATE TONIGHT. SPEEDS MAY REMAIN SOMEWHAT ELEVATED...AND 
THERE ARE LOW PROBABILITIES OF SFC WINDS BECOMING VARIABLE AT TIMES 
TOWARDS SUNRISE. STRONGEST WINDS WILL REMAIN ABOVE 2K FT LIMITING 
THE LLWS POTENTIAL...THOUGH TURBULENCE ABOVE THIS LEVEL MAY CONTINUE 
INTO SUNDAY MORNING. OVERALL WIND SPEED AND DIRECTION TRENDS ARE 
LOWER THAN NORMAL.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NORTHERLY WINDS AROUND 10 KT WILL PERSIST AT KBLH THROUGH SUNDAY 
MORNING BEFORE BECOMING MORE VARIABLE...WHILE WEST WINDS WILL 
TRANSITION IN FOR KIPL. CONFIDENCE IN TIMING THE VARIABLE NATURE TO 
THE WIND DIRECTION IS MODERATE. OTHERWISE...SKIES WILL REMAIN CLEAR 
THROUGH SUNDAY EVENING.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. 

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
HIGH PRESSURE WILL SETTLE INTO THE DESERT SOUTHWEST AND CONTINUED 
ABOVE NORMAL WARMING WILL PERSIST THROUGH THE WEEK AHEAD. BREEZY 
CONDITIONS ARE EXPECTED ON TUESDAY AS A TROUGH PASSES BY TO THE EAST 
OF THE REGION. VERY DRY CONDITIONS WILL PERSIST THROUGH THE WEEK 
WITH NO MENTION OF PRECIPITATION CHANCES DURING THIS TIME PERIOD. 
ELEVATED FIRE DANGER CONCERNS WITH LOW HUMIDITIES AND BREEZY 
CONDITIONS WILL BE PRESENT.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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DISCUSSION...MO/PERCHA
AVIATION...MO/NOLTE
FIRE WEATHER...CDEWEY