049
FXUS65 KPSR 171702
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1000 AM MST MON FEB 17 2025
UPDATE
UPDATED AVIATION
SYNOPSIS
DRY AND GENERALLY TRANQUIL CONDITIONS WILL PREVAIL OVER THE NEXT
SEVERAL DAYS, WITH ABOVE-NORMAL TEMPERATURES BEING COMMON ACROSS THE
REGION. A FEW WEAK SYSTEMS WILL TRAVERSE OVER ARIZONA DURING THE
NEXT WEEK, RESULTING IN LOCALLY BREEZY CONDITIONS AT TIMES.
POTENTIALLY RECORD BREAKING TEMPERATURES ARE EXPECTED BY THE
BEGINNING OF NEXT WEEK AS HIGH PRESSURE IS LIKELY TO DOMINATE OVER
THE DESERT SOUTHWEST.
DISCUSSION
CURRENT ATMOSPHERIC ANALYSIS REVEALS ZONAL FLOW STRETCHING ACROSS
THE DESERT SOUTHWEST, WITH CONSIDERABLE HIGH CLOUD COVER STREAMING
OFF THE EASTERN PACIFIC. THIS FLOW PATTERN WILL TRANSLATE TO QUIET
AND DRY CONDITIONS ACROSS OUR FORECAST AREA THROUGH THE START OF THE
UPCOMING WEEK, WITH CONTINUED PERIODS OF PASSING HIGH CLOUDS. A
PIECE OF SHORTWAVE ENERGY WILL HELP TO TEMPER DOWN H5 HEIGHTS OVER
THE REGION, BUT THIS WEAK DISTURBANCE WILL NOT CREATE ANY NOTICEABLE
IMPACTS. IN TERMS OF TEMPERATURES, WITH H5 HEIGHTS ALOFT DECREASING
AND 850MB TEMPS HOLDING STEADY COMPARED TO SUNDAY, IT WOULD NOT BE
OUT OF THE QUESTION TO SEE SIMILAR, IF NOT SLIGHTLY COOLER
TEMPERATURES THIS AFTERNOON. HOWEVER, THE NBM IS CALLING FOR A FEW
DEGREE INCREASE IN DAY-TO-DAY TEMPERATURES, WITH THE LARGEST BUMP
EXPECTED OUT WEST IN SE CALIFORNIA AND SW ARIZONA. AFTERNOON HIGHS
OVER THESE AREAS WILL REACH INTO THE LOWER 80S AFTER READINGS IN THE
MIDDLE TO UPPER 70S WERE OBSERVED SUNDAY. THIS SLIGHT TEMPERATURE
JUMP IS LIKELY DUE TO THE FORECASTED DECREASE IN CLOUD COVER
OVERHEAD, RESULTING IN MORE INSOLATION. AS FOR PHOENIX AND THE LOWER
DESERTS OF SOUTH-CENTRAL ARIZONA, AFTER SUNDAY SAW READINGS IN THE
LOWER AND MIDDLE 70S, MIDDLE TO UPPER 70S ARE ANTICIPATED THIS
AFTERNOON.
GLOBAL MODELS HAVE THE ABOVE-MENTIONED SYSTEM SKIMMING PAST NORTHERN
ARIZONA ON TUESDAY, RESULTING IN A FURTHER SUPPRESSION OF HEIGHTS
ALOFT. THIS TIME, TEMPERATURES WILL FOLLOW THE SAME TREND AS THESE
FALLING HEIGHTS, BUT A SIGNIFICANT COOLDOWN IS NOT IN THE CARDS AS
HIGHS WILL REMAIN GENERALLY IN THE THE MIDDLE TO UPPER 70S ACROSS
LOWER DESERT AREAS. THE ENHANCED PRESSURE AND THERMAL GRADIENT
ASSOCIATED WITH THIS TRANSIENT SYSTEM WILL ALSO HELP TO GENERATE
LOCALLY BREEZY CONDITIONS ACROSS PORTIONS OF THE REGION, MAINLY
AROUND ENHANCED TERRAIN FEATURES IN SE CALIFORNIA, AND THE LOWER
COLORADO RIVER VALLEY. IN THIS SYSTEMS WAKE, THE GENERAL CONSENSUS
IS THAT WEAK RIDGING WILL BUILD ACROSS THE DESERT SOUTHWEST,
PROMOTING CONTINUED CALM CONDITIONS AND ABOVE-NORMAL TEMPERATURES
THROUGH THE MIDDLE PORTION OF THE WEEK.
HEADING INTO THE END OF THE WEEK, MODELS INDICATE ANOTHER WEAK AREA
OF LOW PRESSURE DIVING ACROSS THE GREAT BASIN AND MOVING OVER
ARIZONA BY THURSDAY/FRIDAY. MUCH LIKE THE PREVIOUS SYSTEM, A PACKING
OF THE PRESSURE AND THERMAL GRADIENTS WOULD LIKELY PROMOTE MORE
BREEZY TO LOCALLY WINDY CONDITIONS ACROSS THE SAME AREAS MENTIONED
ABOVE, WITH THE INCLUSION OF HIGH TERRAIN AREAS IN SOUTH-CENTRAL
ARIZONA. ENHANCED GUSTS, COMBINED WITH LOW RELATIVE HUMIDITY, AND
VERY DRY FUELS, MAY POSE A MARGINAL FIRE RISK FOR THESE AREAS. WITH
MORE SEASONAL HEIGHT ANOMALIES BEING PROJECTED IN CONJUNCTION WITH
THIS DISTURBANCE, DAY-TO-DAY TEMPERATURES MAY DROP A FEW DEGREES,
BUT ONCE AGAIN, A NOTICEABLE COOLDOWN IS NOT ANTICIPATED. LOOKING
BEYOND INTO THE 6-10 DAY PERIOD, ENSEMBLES REMAIN IN EXCELLENT
AGREEMENT REGARDING AN UNSEASONABLY STRONG RIDGE BUILDING OVER MUCH
OF THE WESTERN CONUS, WHICH WOULD PROMOTE MORE DRY CONDITIONS AND
WARMER-THAN-NORMAL TEMPERATURES, WITH READINGS POTENTIALLY REACHING
10-15 DEGREES ABOVE-NORMAL FOR THE END OF FEBRUARY. IN FACT, THE NBM
GIVES NUMEROUS LOCALS A 25-35% CHANCE OF REACHING 90 DEGREES FOR THE
FIRST TIME THIS YEAR BY THE BEGINNING OF NEXT WEEK, ALMOST 20
DEGREES ABOVE SEASONAL LEVELS.
AVIATION
UPDATED AT 1700Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT; AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO SIGNIFICANT WEATHER ISSUES WILL EXIST THROUGH TUESDAY AFTERNOON
UNDER PERIOD OF THICKER HIGH CIRRUS DECKS. WITH SPEEDS GENERALLY
UNDER 10KT, TIMING OF THE USUAL DAILY WIND SHIFTS WILL OCCUR NEAR
THE TYPICAL TIMES, THOUGH THERE MAY BE EXTENDED PERIODS OF
VARIABILITY OR NEARLY CALM CONDITIONS DURING THESE TRANSITION
PERIODS.
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...RW
AVIATION...18
FIRE WEATHER...YOUNG/RW
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