023
FXUS65 KPSR 071201
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
501 AM MST WED JAN 7 2026
UPDATE
UPDATED 12Z AVIATION DISCUSSION.
KEY MESSAGES
- A PAIR OF WEATHER SYSTEMS WILL PRODUCE UNSETTLED CONDITIONS TODAY
AND TOMORROW WITH A COUPLE ROUNDS OF SHOWERS AND BREEZY TO LOCALLY
WINDY CONDITIONS.
- BELOW NORMAL TEMPERATURES ARE EXPECTED THROUGH THE END OF THE
WORKWEEK BEFORE REBOUNDING THIS WEEKEND AS HIGH PRESSURE MAKES A
RETURN.
-DRY CONDITIONS RETURN REGION WIDE ON FRIDAY AND CONTINUE INTO THE
FIRST HALF OF NEXT WEEK.
SHORT TERM /TODAY THROUGH THURSDAY/
AN UNSETTLED WEATHER PATTERN SETS UP TODAY AND WILL CONTINUE THROUGH
THURSDAY AS TWO WEATHER SYSTEMS MOVE THROUGH THE REGION RESULTING IN
A COUPLE ROUNDS OF RAIN, COOLER TEMPERATURES, AND BREEZY TO
LOCALLY WINDY CONDITIONS ACROSS THE REGION. TAKING A LOOK AT
UPPER LEVEL WATER VAPOR SATELLITE IMAGERY EARLY THIS MORNING, WE
CAN SEE THE TWO FEATURES THAT WILL RESULT IN OUR UNSETTLED WEATHER
OVER THE NEXT COUPLE OF DAYS. THE FIRST ONE IS A CLOSED LOW THAT
IS CURRENTLY CENTERED OFF THE NORTHERN COAST OF THE BAJA. THE
SECOND ONE IS A TROUGH DIGGING OFF THE COAST OF THE PACIFIC NW.
THE AFOREMENTIONED CLOSED LOW WILL BE MOVING THROUGH OUR REGION
TODAY AND WILL QUICKLY ADVECT INTO THE PLAINS OVERNIGHT TONIGHT
AND TOMORROW. THE CLOSED LOW WILL MOVE NORTHEASTWARD THROUGH THE
DAY, WEAKEN AS IT DOES, EVENTUALLY BECOMING AN OPEN WAVE, WITH THE
CENTER EVENTUALLY MOVING THROUGH SE AZ BY THIS EVENING. THIS LOW
WILL BRING A DECENT AMOUNT OF MOISTURE AND FORCING (BOTH FROM THE
ASSOCIATED VORTICITY CENTER AND FAVORABLE POSITION OF THE UPPER-
LEVEL JET) ALONG WITH ISENTROPIC ASCENT, RESULTING IN SCATTERED TO
WIDESPREAD RAIN ACROSS MUCH OF THE CWA, SE CA WILL MOST LIKELY
ONLY GET SOME ISOLATED TO SCATTERED LIGHT SHOWERS. CURRENT PWATS
ARE IN THE 0.4- 0.7" RANGE ACROSS THE CWA, AND WILL INCREASE TO
0.8-0.9" (AROUND 200% OF NORMAL) AS THE LOW MOVES THROUGH. THE
SCATTERED TO WIDESPREAD SHOWERS LOOK TO MOVE INTO SW AZ BY THE
EARLY TO MID MORNING TIMEFRAME, AND THEN INTO SOUTH-CENTRAL AZ
(INCLUDING THE PHOENIX METRO) BY THE LATE MORNING HOURS. WITH THE
LOW NOT EXITING THE REGION UNTIL LATE TONIGHT/THE OVERNIGHT
HOURS, OFF AND ON SHOWERS ARE EXPECTED THROUGH THE AFTERNOON AND
EVENING. AS FOR SE CA, THE BEST TIME TO SEE ACTIVITY OUT THERE
WILL BE FROM THE MID MORNING THROUGH THE MID AFTERNOON. WITH THIS
ROUND OF SHOWERS THERE IS LITTLE TO NO INSTABILITY, SO NO
THUNDERSTORMS ARE EXPECTED. ADDITIONALLY, WITH THE LACK OF
INSTABILITY AND ONLY MODERATE MOISTURE RAIN RATES WILL NOT BE
IMPRESSIVE, SO DESPITE THE PROLONGED PERIOD OF RAIN CHANCES QPF
TOTALS WILL REMAIN ON THE LIGHTER SIDE. QPF TOTALS ARE AS
FOLLOWS:
0.00-0.15" FOR SE CA, 0.05-0.30" FOR SW AND SOUTH-CENTRAL AZ, AND
0.30-0.75" FOR THE FOOTHILLS AND HIGHER TERRAIN AREAS.
A BREAK IN ACTIVITY IS EXPECTED DURING THE OVERNIGHT AND MORNING
HOURS ON THURSDAY BEFORE THE SECOND SYSTEM ARRIVES. THE
AFOREMENTIONED SECOND SYSTEM, TROUGH CURRENTLY OFF THE COAST OF
THE PACIFIC NW, LOOKS TO MOVE ONSHORE WEDNESDAY NIGHT INTO
THURSDAY AND DIVE SOUTH/SOUTHEASTWARD, ARRIVING IN OUR CWA BY
THURSDAY AFTERNOON. THIS SYSTEM WILL PUSH A COLD FRONT THROUGH OUR
REGION. THIS FRONT COUPLED WITH THE RESIDUAL MOISTURE FROM THE
FIRST SYSTEM (PWATS OF 0.5-0.6") WILL RESULT IN ISOLATED TO
SCATTERED SHOWERS ALONG AND AHEAD OF THE FRONT. ADDITIONALLY, A
FEW ISOLATED THUNDERSTORMS WILL BE POSSIBLE, AS MUCAPE VALUES
WILL BE AROUND 100-300 J/KG. THIS ACTIVITY IS EXPECTED TO REMAIN
CONFINED TO SOUTH-CENTRAL AZ, WITH THE BEST CHANCES ACROSS THE
HIGHER TERRAIN AREAS NORTH AND EAST OF PHOENIX. QPF VALUES WITH
THIS SYSTEM ARE: AROUND 0.00-0.10" ISOLATED 0.25" ACROSS THE LOWER
DESERTS OF SOUTH-CENTRAL AZ, AND 0.25-0.50" ISOLATED 1.00" ACROSS
THE HIGHER TERRAIN AREAS. ALSO, WITH THIS SYSTEM COMING FROM THE
NW IT WILL BE A COLDER SYSTEM, WITH SNOW LEVELS FALLING TO AROUND
5,000 FT, RESULTING IN ACCUMULATING SNOWFALL ABOVE 5,000-6,000
FEET. ADDITIONALLY, WITH THE MARGINALLY UNSTABLE CONDITIONS AND
LOWERING FREEZING LEVELS, SOME GRAUPEL WILL BE POSSIBLE. ALSO,
GIVEN THE STRONG FORCING, STEEP COLD FRONT, AND DEEPENING SYSTEM
JUXTAPOSED WITH THIS SHALLOW CONVECTION, THESE SHOWERS MAY ALSO
TAP HIGHER MOMENTUM TOWARDS THE SURFACE IN THE FORM OF GUSTS 30+
MPH.
ANOTHER CONSEQUENCE OF A STRONGER VORTICITY CENTER AND SHARPER
NEGATIVE TILT ORIENTATION IS MORE INTENSE UPSTREAM PRESSURE RISES
AND ABILITY TO VERTICALLY MIX STRONGER WINDS BEHIND THE FRONTAL
PASSAGE. THE TREND IN MODEL OUTPUT STRONGLY SUPPORTS A PATTERN OF
RAPIDLY INTENSIFYING (40-50KT) POST FRONTAL H9-H8 WINDS SURGING DOWN
THE LOWER COLORADO RIVER VALLEY LATE THURSDAY AFTERNOON, PEAKING
THURSDAY NIGHT WITH ADDED THERMAL INFLUENCES. HAVE STARTED TO
INCREASE WIND SPEEDS DURING THIS TIME FRAME OVER THE MANDATED NBM
WHICH SEEMS TO NOT BE CAPTURING THE IMPACTS OF SUCH A PATTERN COMMON
DURING THE WINTER. SOME WIND PRODUCTS MAY BE NEEDED, HOWEVER, THE
HIGHEST GUSTS, AND THOSE MEETING WIND ADVISORY CRITERIA, ARE MOSTLY
CONFINED TO THE RIDGETOPS IN SE CA.
WITH MULTIPLE WEATHER SYSTEMS MOVING THROUGH THE REGION ALONG WITH
THE ASSOCIATED RAIN CHANCES AND CLOUD COVER, TEMPERATURES WILL COOL
TO BELOW NORMAL. AFTERNOON HIGH TEMPERATURES ARE FORECASTED TO BE
IN THE UPPER 50S TO MID 60S ACROSS THE MAJORITY OF THE LOWER
DESERTS (MID TO UPPER 60S ACROSS WESTERN IMPERIAL COUNTY AND THE
YUMA AREA) AND IN THE UPPER 40S TO MID 50S ACROSS THE HIGHER
TERRAIN.
LONG TERM /FRIDAY THROUGH TUESDAY/
ENSEMBLES ARE IN PRETTY GOOD AGREEMENT WITH THE OVERALL SYNOPTIC
PATTERN FOR THIS WEEKEND AND HEADING INTO NEXT WEEK. THE TROUGH THAT
WILL BRING US RAIN CHANCES ON THURSDAY WILL QUICKLY ADVECT INTO THE
PLAINS FRIDAY INTO SATURDAY. THIS WILL RESULT IN STRONG SUBSIDENCE
AND AN ABUNDANCE OF DRY AIR OVER OUR REGION. ENSEMBLES SHOW PWATS
DROPPING TO 0.1-0.3" BY FRIDAY. ON FRIDAY WE WILL STILL BE UNDER THE
INFLUENCE OF SOME LOWER HEIGHTS ALOFT, WITH H5 HEIGHTS IN THE 558-
567 DM RANGE, THE WIDE RANGE IS DUE TO THE TROUGH, AND ASSOCIATED
TIGHT PRESSURE GRADIENT, EXITING OUR REGION THROUGH THE DAY. AS A
RESULT, HIGH TEMPERATURES ON FRIDAY WILL BE BELOW NORMAL, WITH HIGHS
IN THE UPPER 50S AND LOW 60S ACROSS THE LOWER DESERTS AND IN THE
UPPER 40S TO LOW 50S ACROSS THE HIGHER TERRAIN. WITH THE TROUGH IN
THE PLAINS ON SATURDAY, H5 HEIGHTS WILL RISE TO A 573-576 DM RANGE.
AS A RESULT TEMPERATURES WILL WARM ON SATURDAY, WITH AFTERNOON HIGH
TEMPERATURES IN THE LOW TO MID 60S ACROSS THE LOWER DESERTS AND IN
THE 50S ACROSS THE HIGHER TERRAIN. ADDITIONALLY ON BOTH FRIDAY AND
SATURDAY MORNING, THE MORNING LOW TEMPERATURES WILL BE SOME OF THE
COLDEST SO FAR THIS WINTER. WITH THE TROUGH QUICKLY EXITING THE
REGION, THE CLOUDS ASSOCIATED WITH THE TROUGH WILL ALSO QUICKLY EXIT
OUR REGION. THIS WILL RESULT IN CLEAR SKIES OVERNIGHT AND MAXIMIZING
RADIATIONAL COOLING. SO, FROST/FREEZE IMPACTS MAY BE AN ISSUE FOR
RURAL VALLEY LOCATIONS AND FREEZE PRODUCTS MAY BE NEEDED. LOW
TEMPERATURES BOTH DAYS ARE CURRENTLY FORECASTED TO DIP INTO THE
LOW TO MID 30S ACROSS RURAL LOWER DESERT LOCATIONS, MID 30S TO LOW
40S ACROSS MORE RURAL LOWER DESERT COMMUNITIES, AND IN THE UPPER
20S TO LOW 30S ACROSS HIGHER TERRAIN AREAS.
A BLOCKING PATTERN WILL DEVELOP THIS WEEKEND WITH HIGH PRESSURE
RETURNING TO WESTERN CONUS, AND CENTERED OVER NORTHERN CA. THIS
PATTERN WILL CONTINUE THROUGH AT LEAST THE BEGINNING OF NEXT
WEEK, WITH THE HIGH PRESSURE STRENGTHENING THROUGH THE FIRST HALF
OF NEXT WEEK. H5 HEIGHTS WILL BE IN THE 576-579 DM RANGE SUNDAY-
TUESDAY. WITH THE HIGH PRESSURE STRENGTHENING THROUGH THE
BEGINNING OF NEXT WEEK, TEMPERATURES WILL GRADUALLY WARM AS A
RESULT. ON SUNDAY AN MONDAY TEMPERATURES ARE FORECASTED TO BE IN
THE UPPER 60S TO LOW 70S ACROSS THE LOWER DESERTS AND IN THE UPPER
50S TO LOW 60S ACROSS THE HIGHER TERRAIN. THEN ON TUESDAY,
AFTERNOON HIGH TEMPERATURES WILL WARM TO THE LOW TO MID 70S ACROSS
THE LOWER DESERTS AND IN THE LOW TO MID 60S ACROSS THE HIGHER
TERRAIN. ADDITIONALLY MORNING LOW TEMPERATURES WILL ALSO WARM,
GOING FROM THE UPPER 30S TO LOW 40S (LOW TO MID 30S) ACROSS THE
LOWER DESERTS (HIGHER TERRAIN) ON SUNDAY TO THE LOW TO UPPER 40S
(MID TO UPPER 30S) ACROSS THE LOWER DESERTS (HIGHER TERRAIN) ON
TUESDAY. ADDITIONALLY, WITH HIGH PRESSURE BUILDING BACK INTO THE
REGION, DRY CONDITIONS RETURN REGION WIDE ON FRIDAY AND CONTINUE
THROUGH AT LEAST THE FIRST HALF OF NEXT WEEK.
AVIATION
UPDATED AT 1200Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE MAIN AVIATION CONCERNS THIS TAF PERIOD WILL BE SHRA AND
IFR/MVFR CIGS. WIND SPEEDS WILL REMAIN LIGHT, GENERALLY AOB 8 KT,
THROUGH THE TAF PERIOD. CURRENT EAST/SOUTHEAST WINDS WILL CONTINUE
THROUGH THE MID-MORNING. SHRA IS EXPECTED TO ARRIVE AROUND 18-19Z,
IT COULD BE AS EARLY AS 17Z. ONCE THE SHRA ARRIVES, WINDS WILL GO
WEST/SOUTHWEST AND CIGS WILL LOWER TO 4-5 KFT. THERE STILL REMAINS
A 60% CHANCE FOR MVFR CIGS AS LOW AS 2-3 KFT DEVELOPING AT ALL
TERMINALS, MAINLY BETWEEN 21Z-01Z THIS AFTERNOON. VISIBILITIES MAY
ALSO FALL TO AS LOW AS 2-3 SM IN ANY HEAVIER POCKETS OF RAIN.
ANOTHER WIND SHIFT TO SOUTHEASTERLY IS EXPECTED DURING THE LATE
AFTERNOON/EARLY EVENING HOURS. WINDS ARE THEN EXPECTED TO GO BACK
WESTERLY, AROUND 03Z, WHEN SHRA IS EXITING AND VCSH REMAINS. VCSH
ARE EXPECTED TO REMAIN AROUND THE AREA UNTIL 07Z. THE LOWER CIGS,
4-5 KFT, ARE EXPECTED TO REMAIN THROUGH THE OVERNIGHT HOURS
DESPITE SHRA/VCSH EXITING THE AREA.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
THE MAIN AVIATION CONCERN THIS TAF PERIOD WILL BE VCSH/SHRA FROM
THE MID-MORNING THROUGH THE MID-AFTERNOON AND LOWER CIGS. WIND
SPEEDS AT BOTH TERMINALS WILL BE LIGHT, GENERALLY AOB 7 KT,
THROUGH THE PERIOD. WIND DIRECTIONS AT KIPL ARE CURRENTLY WESTERLY
AND WILL GO LIGHT AND VARIABLE FROM THE MID-MORNING THROUGH THE
AFTERNOON, BEFORE GOING BACK WESTERLY/SOUTHWESTERLY. AT KBLH,
WINDS ARE CURRENTLY NORTHWESTERLY, AND WILL GO LIGHT AND VARIABLE
FROM LATE THIS MORNING THROUGH THE AFTERNOON, BEFORE GOING
SOUTHERLY THIS EVENING AND THEN SOUTHWESTERLY LATE THIS EVENING
AND THROUGH THE OVERNIGHT HOURS. CIGS ARE EXPECTED TO LOWER TO
AROUND 5-6 KFT AS VCSH/SHRA MOVES INTO SE CA. THESE SHOWERS WILL
EXIT THE REGION BY THE LATE AFTERNOON HOURS, WITH GRADUALLY
CLEARING SKIES.
FIRE WEATHER
MOISTURE LEVELS WILL REMAIN ELEVATED THROUGH THURSDAY WITH
WETTING RAINFALL CHANCES HEIGHTENED ACROSS EASTERN DISTRICTS AS A
PAIR OF WEATHER DISTURBANCES PASS THROUGH THE REGION. MUCH DRIER
CONDITIONS WILL RETURN ON FRIDAY AND CONTINUE INTO NEXT WEEK.
MINRHS TODAY WILL BE IN THE 50-70% REGION WIDE WITH EXCELLENT
OVERNIGHT RECOVERY. TOMORROW, MINRHS WILL BE IN A 50-80% RANGE
ACROSS THE CENTRAL AND EASTERN DISTRICTS AND WILL BE IN THE
20-40% RANGE ACROSS THE WESTERN DISTRICTS, WITH EXCELLENT
OVERNIGHT RECOVERY IN THE EASTERN DISTRICTS AND GOOD OVERNIGHT
RECOVERY IN THE WESTERN DISTRICTS. BY FRIDAY, MINRH WILL FALL INTO
A 15-35% RANGE, WITH GOOD OVERNIGHT RECOVERY, REGION WIDE AND
WILL CONTINUE THROUGH THE FIRST HALF OF NEXT WEEK. STRONG
NORTHERLY WIND GUSTS IN EXCESS OF 30 MPH WILL LIKELY SURGE INTO
THE LOWER COLORADO RIVER VALLEY THURSDAY AFTERNOON THROUGH FRIDAY
MORNING YIELDING AN ELEVATED FIRE DANGER. ELSEWHERE, GUSTS SHOULD
BE SOMEWHAT WEAKER WITH LESSER IMPACTS BEFORE RETURNING TO MORE
SEASONAL LEVELS OVER THE WEEKEND.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...BERISLAVICH
LONG TERM...BERISLAVICH
AVIATION...BERISLAVICH
FIRE WEATHER...BERISLAVICH/18
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