554
FXUS65 KPSR 022310
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
410 PM MST SAT MAY 2 2026
UPDATE
UPDATED AVIATION DISCUSSION
KEY MESSAGES
- ABOVE NORMAL TEMPERATURES THIS WEEKEND WILL BRIEFLY COOL INTO A
BELOW NORMAL RANGE EARLY NEXT WEEK.
- BREEZY TO LOCALLY WINDY CONDITIONS WILL MATERIALIZE EARLY NEXT
WEEK WITH MODEST RAIN CHANCES ACROSS ARIZONA HIGHER TERRAIN AREAS.
- A RAPID WARMING TREND WITH ABOVE NORMAL TEMPERATURES IS LIKELY TO
RETURN DURING THE LATTER HALF OF NEXT WEEK.
SHORT TERM /TODAY THROUGH MONDAY/
EARLY AFTERNOON WV IMAGERY DEPICTS A WEAK VORTICTY CENTER OVER THE
FOUR CORNERS PROPAGATING SE WHILE SHORTWAVE RIDGING BUILDS DIRECTLY
OVER THE CWA. DEEPER NEGATIVE HEIGHT ANOMALIES UPSTREAM OVER THE
EAST PACIFIC ARE IN THE PROCESS OF CUTTING OFF WEST OF THE
CALIFORNIA COAST INDICATIVE OF HEMISPHERIC PATTERN AMPLIFICATION AND
BLOCKING DEVELOPMENT (COMMON PATTERN EVOLUTION IN MAY). WHILE
AMPLIFIED BLOCKING TYPICALLY PROVIDES INCREASED ENSEMBLE SPREAD AND
REDUCED FORECAST CONFIDENCE, ONLY MINOR DIFFERENCES ARE NOTED
AFFECTING TIMING AND DEPTH OF ENERGY MOVING THROUGH THE REGION NEXT
WEEK. AS SUCH, THERE IS GOOD CONFIDENCE OF TEMPORARY SHORTWAVE
RIDGING WITH ABOVE NORMAL TEMPERATURES THIS WEEKEND GIVING WAY TO
GRADUAL HEIGHT FALLS AND POSITIVELY TILTED TROUGHING WITH BELOW
NORMAL TEMPERATURES SLOWLY PROGRESSING THROUGH THE REGION EARLY NEXT
WEEK.
THE AFOREMENTIONED FOUR CORNERS SHORTWAVE AND ASSOCIATED COLD AIR
ALOFT HAS SUPPORTED DEEPER CONVECTION OVER THE WHITE MOUNTAINS THIS
AFTERNOON. WHILE A SHOWER COULD CONCEIVABLY CLIP EASTERN GILA CO,
THE GREATER INFLUENCE OF THIS ACTIVITY WILL BE TO REESTABLISH THE
ENHANCED EASTERLY WIND GRADIENT WITH INCREASED OVERNIGHT/MORNING
GUSTS OVER RIDGE TOPS, EVENTUALLY MIXING INTO LOWER ELEVATIONS
THOUGH WITH LITTLE TO NO ADVERSE IMPACTS. OTHERWISE, WITH H5 HEIGHTS
IN A 574-578DM RANGE, NARROW ENSEMBLE GUIDANCE SPREAD YIELDS
EXCELLENT CONFIDENCE OF TEMPERATURE 4F-8F ABOVE NORMAL CONTINUING
SUNDAY. AS THE CLOSED LOW APPROACHES THE SOUTHWEST SUNDAY
AFTERNOON/EVENING, THE COMBINATION OF MIDTROPOSPHERIC HEIGHT FALLS,
ENHANCED JET ENERGY, AN EXPANSIVE AND DEEPENING MARINE LAYER IN SAN
DIEGO COUNTY, AND A FRONTAL PASSAGE WILL SUPPORT INTENSIFYING
DOWNSLOPE FLOW AND MOUNTAIN ROTORS ACROSS WESTERN IMPERIAL COUNTY.
WHILE THERE REMAINS SOME MODEL DISCREPANCY REGARDING THE EXTENT AND
MAGNITUDE OF WIND GUSTS, PATTERN RECOGNITION AND SEVERAL HIGH
RESOLUTION MODELS SUGGEST SOLID WIND ADVISORY CRITERIA WITH SOME
MODELING INDICATING A HIGHER END ADVISORY EVENT.
HEIGHT FALLS AND CYCLONIC FLOW WITHIN A POSITIVELY TILTED TROUGH
WILL SLOWLY MIGRATE INLAND MONDAY WITH H5 READINGS IN A 568-574DM
RANGE RESULTING IN RATHER ABRUPT COOLING AND HIGH TEMPERATURES
FALLING BELOW NORMAL MONDAY SOME 10F-15F COOLER THAN SUNDAY.
INCREASED WIND SPEEDS THOUGH THE DEPTH OF THE TROPOSPHERE WILL
TRANSLATE INTO WIDESPREAD GUSTS MONDAY AFTERNOON; AND WHILE WELL
SHORT OF ADVISORY CRITERIA COULD YIELD SOME LOCALIZED BLOWING DUST
AND REGIONAL HAZY SKIES. GLOBAL MODELS REMAIN CONSISTENT IN
ADVERTISING A PLUME OF MIDLEVEL MOISTURE BEING PULLED INTO THE SW
FLOW OVER SOUTHERN ARIZONA MONDAY EVENING/OVERNIGHT ALONG AN
ELEVATED FRONT. WHILE PWAT ANOMALIES ASSOCIATED WITH THIS FEATURE
MAY REACH 200% OF NORMAL, TYPICAL MOISTURE LEVELS ARE SO LOW THIS
TIME OF YEAR, RAW TOTAL COLUMN PWATS ONLY APPEAR TO REACH NEAR 0.75"
AND LARGELY PACKED ABOVE 600MB WITH LOW LEVEL MIXING RATIOS ONLY 5-7
G/KG. SYNOPTIC FORCING LOOKS QUITE ROBUST AT THIS TIME, HOWEVER THE
AMOUNT OF SUB-CLOUD DRY AIR AND MODEL TRENDS TOWARDS FOCUSING THIS
MOISTURE PLUME FARTHER TO THE SOUTH NEAR TUCSON SHOULD PRECLUDE MUCH
OF THE CWA FROM RECEIVING ACCUMULATING RAINFALL. HAVE TRIMMED THE
MANDATED NBM POPS IN EXPANSE AND MAGNITUDE GIVEN THE APPEARANCE OF
THE TYPICAL MODEL ARTIFACTS WITH ONLY A 10-20% CHANCE OF
ACCUMULATIONS OVER HIGHER TERRAIN LOCATIONS SOUTHWEST OF PHOENIX
HEADING INTO TUESDAY MORNING.
LONG TERM /TUESDAY THROUGH FRIDAY/
AS THE THE UPPER LOW MOVES THROUGH THE DESERT SW TUESDAY,
TEMPERATURES WILL COOL FURTHER WITH AFTERNOON HIGHS ONLY REACHING
THE UPPER 70S/LOWER 80S ACROSS THE LOWER DESERTS. THIS WILL BE A
SOLID 10 DEGREES BELOW NORMAL FOR EARLY MAY, AND QUITE POSSIBLY THE
COOLEST TEMPERATURES ACROSS THE FORECAST AREA FOR THE NEXT 6 MONTHS.
BREEZY CONDITIONS WILL ALSO REMAIN IN PLACE ACROSS MUCH OF THE
REGION. THE LOW WILL FINALLY EXIT EAST BY MIDWEEK WITH UPPER LEVEL
RIDGING BUILDING ALONG THE WEST COAST. THERE ARE INDICATIONS FROM
GUIDANCE THAT A PIECE OF ENERGY LEFT BEHIND FROM THE DEPARTING LOW
COULD DEVELOP INTO A WEAK CUTOFF LOW OVER THE BAJA PENINSULA DURING
THE LATTER HALF OF THE WEEK, BUT AS OF RIGHT NOW, IT LOOKS TO BE TOO
FAR TO THE SOUTH TO HAVE ANY SENSIBLE WEATHER IMPACTS FOR OUR
REGION. WITH 500 MB HEIGHT FIELDS RAPIDLY RISING TO AROUND 580DM
FROM THE BUILDING RIDGE, TEMPERATURES BY THE LATTER HALF OF THE WEEK
WILL BE ON A RAPID WARMING TREND. THE LATEST NBM IS SHOWING
AFTERNOON HIGHS ACROSS THE LOWER DESERTS RAPIDLY WARMING FROM THE
MIDDLE 80S ON WEDNESDAY TO MIDDLE 90S ON THURSDAY. ADDITIONAL
WARMING INTO THE TRIPLE DIGITS, WHICH WOULD BE THE FIRST OCCURRENCE
SINCE THE UNPRECEDENTED EARLY SEASON HEATWAVE FROM LATE MARCH, IS
BEING SHOWN STARTING FRIDAY.
AVIATION
UPDATED AT 2310Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
LOW CONFIDENCE IN PREVAILING WIND DIRECTIONS WILL BE THE MAIN
AVIATION CONCERNS THIS EVENING. 130V240 CONDITIONS MAY LAST UNTIL
A FEW HOURS AFTER SUNSET BEFORE AND E'RLY COMPONENT BECOMES
ESTABLISHED EARLY TONIGHT. MORNING GUSTS ARE LIKELY TO BE OBSERVED
ONCE AGAIN SOON AFTER SUNRISE WITH READINGS GENERALLY RANGING
BETWEEN 15-20 KTS THROUGH ABOUT 18Z. SPEEDS SHOULD RELAX A BIT AS
DIRECTIONS VEER MORE TOWARD THE S BY THE EARLY AFTERNOON HOURS,
WITH SEVERAL HOURS OF CROSS-RUNWAY WINDS POSSIBLE AT KPHX AND
KDVT. SCT-BKN MID TO HIGH CLOUDS WILL BE PRESENT THROUGH VIRTUALLY
ALL OF THE FORECAST WINDOW.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS WILL EXIST THROUGH MOST OF THE TAF
PERIOD. WINDS AT KIPL WILL SWITCH WILL EVENTUALLY SWING TO THE W
EARLY TONIGHT BEFORE AN E'RLY COMPONENT TAKES OVER ONCE AGAIN JUST
BEFORE SUNRISE. AT KBLH, VRB CONDITIONS WILL EXTENDED THROUGH
MOST, IF NOT ALL, OF THE EVENING AND NIGHTTIME HOURS, WITH A
S'RLY COMPONENT BECOMING ESTABLISHED BY SUNDAY MORNING. GUSTS
BEGIN TO PICK UP LATER IN THE PERIOD WITH READINGS AROUND 20 KT.
SCT-BKN MID TO HIGH CLOUDS WILL BE PRESENT OVER THE REGION DURING
THE NEXT 24 HOURS.
FIRE WEATHER
DRY CONDITIONS AND ABOVE NORMAL TEMPERATURES WILL BE OBSERVED
THROUGH THE WEEKEND. A LOW PRESSURE SYSTEM WILL GRADUALLY APPROACH
THE CA COAST LATE THIS WEEKEND, RESULTING IN WIDESPREAD BREEZY TO
LOCALLY WINDY CONDITIONS INTO EARLY NEXT WEEK AND TEMPERATURES
COOLING INTO A BELOW NORMAL CATEGORY MONDAY-TUESDAY. GUSTY AFTERNOON
WINDS COMBINED WITH LOW HUMIDITIES WILL LIKELY PRODUCE ELEVATED FIRE
WEATHER CONDITIONS SUNDAY FOR PORTIONS OF THE WESTERN DISTRICTS,
INCLUDING THE LOWER COLORADO RIVER VALLEY. AS THE LOW PRESSURE
SYSTEM MOVES THROUGH THE DESERT SOUTHWEST EARLY NEXT WEEK, THE
CHANCE OF SHOWERS WILL INCREASE LATE MONDAY INTO THE FIRST PART OF
TUESDAY ACROSS THE FAR EASTERN DISTRICTS, HOWEVER, THE PROBABILITY
OF WETTING RAINS WILL REMAIN ON THE LOW SIDE. AFTERNOON MINRHS
BETWEEN 8-15% WILL BE COMMON TODAY, INCREASING SLIGHTLY INTO A 10-
20% RANGE SUNDAY AND 15-30% RANGE EARLY NEXT WEEK.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...18
LONG TERM...18/LOJERO
AVIATION...RW
FIRE WEATHER...LOJERO/WHITTOCK
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