389
FXUS65 KPSR 170509
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1009 PM MST SUN FEB 16 2025
UPDATE
UPDATED AVIATION DISCUSSION.
SYNOPSIS
DRY AND VERY TRANQUIL WEATHER WILL BE COMMON ACROSS THE REGION THIS
WEEK AS TEMPERATURES HOVER IN AN ABOVE NORMAL RANGE. A COUPLE WEAK
WEATHER SYSTEMS WILL MOVE THROUGH NORTHERN ARIZONA DURING THE WEEK,
THOUGH ONLY PRODUCING SOME LOCALLY BREEZY CONDITIONS AT TIMES.
UNUSUALLY WARM AND NEAR RECORD BREAKING TEMPERATURES MAY ARRIVE INTO
THE AREA EARLY NEXT WEEK.
DISCUSSION
THE HEMISPHERIC PATTERN OVER THE NEXT WEEK WILL SETTLE INTO A VERY
STABLE CONFIGURATION WITH BROAD TROUGHING AND NEGATIVE HEIGHT
ANOMALIES SITUATED OVER SE CANADA AND THE NE CONUS, WHILE EXPANSIVE
RIDGING DEVELOPS OVER THE EAST PACIFIC AND WESTERN CONUS. ENSEMBLE
MEMBERSHIP CONTINUES TO AGREE THAT THE SW CONUS WILL OSCILLATE
BETWEEN QUASI-ZONAL AND NORTHWEST FLOW AS A COUPLE LOW AMPLITUDE
SHORTWAVE SHEAR INTO THE DOWNSTREAM MEAN LONGWAVE TROUGH POSITION.
NEVERTHELESS, FORECAST CONFIDENCE IS EXCELLENT THAT H5 HEIGHTS WILL
PRIMARILY FALL IN A 574-578DM RANGE WITH ONLY BRIEF RESPITES CLOSER
TO 570DM DURING THE SHORTWAVE PASSAGES. AS A RESULT, MODEL GUIDANCE
SPREAD IS EXTREMELY NARROW ADVERTISING TEMPERATURES HOVERING 5F-10F
ABOVE NORMAL THROUGHOUT THE WEEK.
WHILE ONE SHORTWAVE WILL PASS THROUGH THE FOUR CORNERS TUESDAY, ALL
RECENT MODEL ITERATIONS SUGGEST THIS FEATURE WILL BE VERY LOW
AMPLITUDE AND TRANSITORY SUCH THAT IMPACTS ON TEMPERATURES WILL BE
ALMOST NEGLIBLE, AND ONLY MODEST INCREASES IN WIND GUSTS WOULD BE
POSSIBLE. THE PREPONDERANCE OF ENSEMBLE MEMBERS INDICATE A SOMEWHAT
MORE DEFINED SHORTWAVE WILL DIVE INTO NORTHERN ARIZONA
THURSDAY/FRIDAY. THOUGH THE INLAND TRAJECTORY SHOULD NEGATE ANY
MOISTURE AVAILABILITY, THIS TYPE OF PATTERN OF HEIGHT FALLS AND
THERMAL GRADIENT WOULD SUPPORT OF PERIOD OF GUSTY NORTH WINDS
SURGING DOWN THE LOWER COLORADO RIVER VALLEY. THIS COULD POSE A
MARGINAL FIRE WEATHER RISK FOR ANY REMNANT DESSICATED FUELS LEFT
OVER FROM LAST WINTER. OTHERWISE, ALL ENSEMBLE SUITES REMAIN IN
REMARKABLE AGREEMENT WITH RESPECT TO THE PATTERN IN THE DAY 6-10
PERIOD ADVERTISING STRONG POSITIVE HEIGHT ANOMALIES BUILDING OVER
THE SW CONUS WITH H5 HEIGHTS LIKELY ECLIPSING 580DM (AND POSSIBLY AS
HIGH AS 585DM). IT'S NOT COMMON TO SEE THIS TYPE OF AGREEMENT AMONG
MODELS THIS FAR IN ADVANCE AND YIELDS UNUSUALLY HIGH CONFIDENCE OF
TEMPERATURES 10F-15F ABOVE NORMAL DURING THE FIRST PART OF NEXT
WEEK. IN FACT, GUIDANCE DISTRIBUTIONS SUGGEST AT LEAST A 25% CHANCE
OF PHOENIX REACHING RECORD HIGHS SOME 20F ABOVE NORMAL (I.E. THE
LOWER 90S FOR THE FIRST TIME THIS YEAR).
AVIATION
UPDATED AT 0508Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT;
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
LIGHT DIURNAL WINDS, MOSTLY AOB 8 KTS, WILL PREVAIL AT ALL
TERMINALS THROUGH THE TAF PERIOD. EXTENDED PERIODS OF CALM AND
LIGHT VARIABLE WINDS ARE ALSO ANTICIPATED. SCT TO BKN HIGH CIRRUS
WILL CONTINUE OVER THE REGION THROUGH MOST OF THE PERIOD.
FIRE WEATHER
DRY CONDITIONS WITH DAILY MINRH'S RANGING IN THE MID TO UPPER TEENS
REGION-WIDE WILL PERSIST THROUGH THIS WEEK. WINDS WILL GENERALLY
FOLLOW TYPICAL DIURNAL TENDENCIES EACH DAY THROUGH MONDAY, WITH THE
NEXT ROUND OF BREEZY CONDITIONS DEVELOPING ACROSS THE WESTERN
DISTRICTS ON TUESDAY. TEMPERATURES WILL REMAIN ABOVE NORMAL AROUND 5-
10 DEGREES THROUGH THIS WEEK.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
DISCUSSION...18
AVIATION...SMITH/BENEDICT
FIRE WEATHER...YOUNG
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