490  
FXUS65 KPSR 182351  
AFDPSR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PHOENIX AZ  
451 PM MST SUN JAN 18 2026  
   
UPDATE  
00Z AVIATION DISCUSSION.  
 
 
   
KEY MESSAGES  
 
- STRONG HIGH PRESSURE ACROSS THE REGION WILL PERSIST FOR MUCH OF  
THE COMING WEEK LEADING TO ABOVE NORMAL TEMPERATURES AND DRY  
CONDITIONS.  
 
- UNSETTLED WEATHER MAY AFFECT THE REGION BY NEXT WEEKEND WITH  
RAIN CHANCES POTENTIALLY RETURNING AND TEMPERATURES DROPPING  
CLOSER TO NORMAL.  
 
 
   
SHORT TERM /TODAY THROUGH TUESDAY/  
 
AN OMEGA BLOCKING PATTERN WITH RIDGING THROUGHOUT THE WESTERN  
U.S. AND SOUTHWEST CANADA AND DEEP TROUGHING ACROSS THE EASTERN  
CONUS AND CANADA CAN BE SEEN ON GOES SATELLITE. ACROSS THE REGION  
TODAY H5 HEIGHTS WILL BE IN THE 90TH PERCENTILE OF CLIMATOLOGY BEFORE  
LOWERING ON MONDAY TO NEAR NORMAL. HOWEVER, TEMPERATURES IN THE  
LOWER DESERTS WILL CONTINUE TO RANGE BETWEEN 72-77 DEGREES. PASSING  
HIGH CLOUDS HAVE ALREADY BEGAN TO MOVE INTO THE REGION AND WILL  
BE COMMON THROUGH MONDAY BEFORE CLEARING BY TUESDAY MORNING.  
 
 
   
LONG TERM /WEDNESDAY THROUGH SATURDAY/  
 
UPPER LEVEL RIDGING IS FORECAST TO CONTINUE ON WEDNESDAY AND  
LIKELY INTO THURSDAY BEFORE MUCH OF THE WESTERN U.S. BEGINS TO  
FALL UNDER SOME MODEST TROUGHING BY FRIDAY. AT THE SAME TIME, A  
CUT-OFF LOW WILL DEVELOP OFF THE COAST OF CALIFORNIA WITH THE BULK  
OF THE ENSEMBLE GUIDANCE POINTING AT THIS DISTURBANCE NOT GAINING  
MUCH STRENGTH AND EVENTUALLY DRIFTING SOUTHEASTWARD BY NEXT  
WEEKEND. THE SHIFT AWAY FROM THE RIDGING LATER THIS WEEK SHOULD  
LOWER OUR TEMPERATURES MODESTLY BY FRIDAY INTO NEXT WEEKEND, BUT  
SO FAR THE NBM KEEPS OUR TEMPERATURES BARELY TOUCHING THE NORMAL  
RANGE. THE CUT-OFF LOW COULD GET CLOSE ENOUGH TO AFFECT PORTIONS  
OF OUR REGION BY NEXT WEEKEND, BUT MODEL TRENDS HAVE BEEN LEANING  
TOWARD THE SYSTEM MOSTLY BYPASSING OUR REGION TO THE SOUTH. MODELS  
HAVE A DIFFICULT TIME HANDLING THESE CUT-OFF LOWS, SO FORECAST  
CONFIDENCE REMAINS QUITE LOW FOR FRIDAY INTO NEXT WEEKEND. BETWEEN  
THE GEFS AND THE EPS, AROUND 25% OF THE MEMBERS SHOW DECENT RAIN  
CHANCES WITH THE CUT-OFF LOW. MODELS ARE NOT LIKELY TO HAVE A GOOD  
HANDLE ON THIS SYSTEM UNTIL AT LEAST THE MIDDLE OF THE WEEK.  
 
 
   
AVIATION  
UPDATED AT 2350Z.  
 
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT AND  
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH::  
NO AVIATION CONCERNS ARE EXPECTED DURING THE TAF PERIOD. WINDS  
WILL FOLLOW LIGHT AND DIURNAL TRENDS WITH VRB TO CALM CONDITIONS  
BEING COMMON THROUGH THE TAF PERIOD. FEW-SCT HIGH CIRRUS DECKS  
WILL BE PRESENT DURING THE FORECAST WINDOW, AND MAY BECOME BKN AT  
TIMES.  
 
 
   
FIRE WEATHER  
 
STRONG HIGH PRESSURE WILL PERSIST ACROSS THE REGION OVER THE NEXT  
SEVERAL DAYS KEEPING TEMPERATURES ABOVE NORMAL AND DRY CONDITIONS  
IN PLACE. DAILY MINRH VALUES WILL REMAIN STABLE, FALLING TO  
15-20% EACH DAY WITH OVERNIGHT RECOVERIES OF 30-50%. 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.  
 
 
   
PSR WATCHES/WARNINGS/ADVISORIES  
 
AZ...NONE.  
CA...NONE.  
 
 
 
 
SHORT TERM...RYAN/KUHLMAN  
LONG TERM...KUHLMAN  
AVIATION...BERISLAVICH/RW  
FIRE WEATHER...RYAN/KUHLMAN  
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