705
FXUS65 KPSR 201902
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1202 PM MST TUE JAN 20 2026
KEY MESSAGES
- HIGH PRESSURE WILL CONTINUE TO BE THE DOMINANT FEATURE OVER THE
DESERT SOUTHWEST, RESULTING IN ABOVE-NORMAL TEMPERATURES AND DRY
CONDITIONS THROUGH THE NEXT FEW DAYS.
- WEAK LOW PRESSURE WILL MEANDER ITS WAY TOWARD THE REGION BY
LATE IN THE WEEK AND INTO THE WEEKEND BRINGING COOLER TEMPS AND
CHANCES FOR RAINFALL.
SHORT TERM /TODAY THROUGH THURSDAY/
CURRENT OBJECTIVE ANALYSIS REVEALS HIGH AMPLITUDE RIDGING
CONTINUING TO DOMINATE MUCH OF THE WESTERN CONUS WHILE A
SHORTWAVE TROUGH EMBEDDED IN THE BROADER FLOW PATTERN DIVES SOUTH
TOWARD THE NORTHERN ROCKIES. THE LATTER OF THESE FEATURES, PLUS
ANOTHER FOLLOW ON DISTURBANCE, WILL BEGIN TO ERODE THE STUBBORN
AREA OF HIGH PRESSURE OVER THE NEXT FEW DAYS, BUT DRY CONDITIONS
WITH ABOVE-NORMAL TEMPERATURES WILL CONTINUE. THE ONLY IMPACT
EXPECTED AS THESE DUPLICATE SHORTWAVES SHAVE AWAY AT HEIGHTS ALOFT
IS VERY MINIMAL DOWNTREND IN DAY-TO-DAY TEMPERATURES. HIGHS THIS
AFTERNOON FOR LOWER DESERT LOCATIONS WILL RANGE BETWEEN 71-78
DEGREES BEFORE FALLING TO BETWEEN 70-75 DEGREES BY THURSDAY.
THE BREAKDOWN OF THE RIDGE WILL ALSO ALLOW FOR THE ADVANCEMENT OF AN
EASTERN PACIFIC DISTURBANCE TOWARD THE WEST COAST DURING THE LATTER
HALF OF THE WEEK. MOISTURE ALOFT OUT AHEAD OF THIS SYSTEM WILL
TRANSLATE TO INCREASING CLOUD COVER AS EARLY AS WEDNESDAY MORNING.
MOISTURE WILL CONTINUE TO INCREASE HEADING INTO THURSDAY, SATURATING
THE COLUMN FROM THE TOP DOWN, SO OTHER THAN SOME POSSIBLE VIRGA,
THE DRY SUB-CLOUD LAYER WILL KEEP CONDITIONS AT THE SURFACE QUIET
DURING THIS TIMEFRAME. THESE INCREASING CLOUDS WILL ALSO AID IN
THE PREVIOUSLY-MENTIONED COOLING TREND. BETTER MOISTURE IN THE MID
TO LOWER LEVELS WILL BEGIN TO BE PULLED INTO SOUTHERN ARIZONA BY
LATE THURSDAY, SETTING THE STAGE FOR SOME POTENTIAL RAINFALL FOR
THE END OF THE WEEK.
LONG TERM /FRIDAY THROUGH MONDAY/
MOISTURE ACROSS THE AREA SHOULD PEAK FROM FRIDAY AFTERNOON THROUGH
FRIDAY NIGHT WITH THE BEST MOISTURE LIKELY BEING FOCUSED ACROSS
SOUTHEAST ARIZONA. MODEL TRENDS OVER THE LAST COUPLE OF DAYS HAVE
LEANED TOWARD THE MORE BULLISH CASE FOR THIS WEATHER SYSTEM
BRINGING RAINFALL TO AT LEAST PORTIONS OF OUR REGION. DESPITE THE
CENTER OF THE LOW MISSING OUR AREA TO THE SOUTH AND IT WEAKENING
BY THE TIME IT REACHES NORTHERN BAJA, WE ARE LIKELY TO SEE MOST OF
OUR FORCING FOR PRECIPITATION FROM A COMBINATION OF THE UPPER JET
AND LOW LEVEL OROGRAPHIC LIFT. THIS IS NOT EXACTLY AN GOOD RECIPE
FOR WIDESPREAD RAINFALL, BUT IT SHOULD BE ENOUGH TO BRING A PERIOD
OF MAINLY LIGHT SHOWERS FROM AS EARLY AS FRIDAY AFTERNOON THROUGH
AT LEAST SATURDAY MORNING. INITIAL DRY AIR IN THE LOW LEVELS
SHOULD LIMIT THE RAINFALL DURING THE FIRST HALF OF THE EVENT WITH
THE BEST CHANCES FOR MEASURABLE RAINFALL LIKELY OCCURRING DURING
THE OVERNIGHT HOURS FRIDAY NIGHT. THERE ARE ALSO SOME INDICATIONS
OF SOME WEAK INSTABILITY DURING THE DAYTIME HOURS SATURDAY IF THE
COLD CORE IS CLOSE ENOUGH TO SOUTHERN AND/OR CENTRAL ARIZONA. THIS
COULD LEAD TO SOME ADDITIONAL ISOLATED TO SCATTERED SHOWER
ACTIVITY ON SATURDAY. FORECAST RAINFALL FOR THIS EVENT IS EXPECTED
TO BE FAIRLY LIGHT WITH THE MOST RECENT GUIDANCE SHOWING UPWARDS
OF A 0.10" ACROSS THE PHOENIX AREA TO 0.25-0.50" FOR THE EASTERN
ARIZONA HIGH TERRAIN. SINCE THIS WILL AGAIN BE A FAIRLY WARM
WEATHER SYSTEM, SNOW LEVELS ARE EXPECTED TO MOSTLY STAY ABOVE 7000
FEET.
UPPER LEVEL RIDGING IS THEN FAVORED TO QUICKLY PUSH INTO THE
REGION FROM THE WEST ON SUNDAY WITH DRY AIR SURGING IN FROM THE
NORTH BY SUNDAY AFTERNOON. AS HIGH PRESSURE AND DRY AIR SETTLES
OVER THE REGION EARLY NEXT WEEK, WE ARE LIKELY TO SEE THE NEAR
NORMAL TEMPERATURES ON FRIDAY-SUNDAY QUICKLY TREND UPWARD.
GUIDANCE SUGGESTS WE SHOULD SEE A RETURN OF ABOVE NORMAL
TEMPERATURES BY AROUND NEXT TUESDAY OR WEDNESDAY.
AVIATION
UPDATED AT 1655Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION WEATHER CONCERNS ARE EXPECTED THROUGHOUT THE TAF
PERIOD. THE OVERALL WIND PATTERN WILL EXHIBIT LIGHT, DIURNAL
TENDENCIES WITH SPEEDS AOB 6 KTS ALONG WITH EXTENDED PERIODS OF
VARIABLE TO CALM CONDITIONS. MOSTLY CLEAR SKIES CAN BE EXPECTED
THROUGH TONIGHT BEFORE MID TO HIGH-LEVEL CLOUDS GRADUALLY INCREASE
THROUGHOUT THE DAY WEDNESDAY.
FIRE WEATHER
DRY CONDITIONS WITH ABOVE NORMAL TEMPERATURES WILL PERSIST
THROUGH MID WEEK. DAILY MINRH VALUES ARE EXPECTED TO REMAIN
BETWEEN 15-20% EACH DAY WITH OVERNIGHT RECOVERIES OF 30-60%.
WINDS WILL OVERALL BE LIGHT THROUGH THE PERIOD WITH ONLY SOME
PERIODIC LIGHT BREEZINESS ACROSS THE LOWER CO RIVER VALLEY AND
OVER THE ARIZONA HIGH TERRAIN. THE WEATHER PATTERN WILL CHANGE
LATE IN THE WEEK TO ALLOW FOR COOLER TEMPERATURES, AN INCREASE IN
HUMIDITIES AND RAIN CHANCES BY FRIDAY OR SATURDAY.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...RW
LONG TERM...KUHLMAN
AVIATION...LOJERO
FIRE WEATHER...KUHLMAN
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