456  
FXUS66 KHNX 190506  
AFDHNX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE HANFORD CA  
1006 PM PDT SUN MAY 18 2025  
   
UPDATE  
 
AVIATION SECTION UPDATED  
 
 
 
 
   
KEY MESSAGES  
 
1. WINDS WILL INCREASE AGAIN OVERNIGHT INTO MONDAY MORNING IN THE  
MOJAVE DESERT SLOPES, WITH A 70 PERCENT CHANCE FOR WIND GUSTS  
GREATER THAN 55 MPH. A HIGH WIND WARNING REMAINS IN EFFECT.  
 
2. ELEVATED FIRE WEATHER CONDITIONS WILL BE PRESENT TODAY AND  
MONDAY ALONG THE WEST SIDE HILLS AND WESTERN SAN JOAQUIN VALLEY  
DUE TO LOW RELATIVE HUMIDITY VALUES AND INCREASED WINDS.  
 
3. ABOVE AVERAGE TEMPERATURES RETURN MONDAY AND WILL WARM  
THROUGH THE WEEK. MODERATE HEAT RISK IS EXPECTED ACROSS THE SAN  
JOAQUIN VALLEY ON WEDNESDAY.  
 
 
   
DISCUSSION  
 
NEAR AVERAGE TEMPERATURE WILL BE PRESENT ACROSS THE REGION THIS  
AFTERNOON AS THE UPSTREAM PORTION OF AN UPPER LEVEL TROUGH  
MOVES THROUGH. NORTHWESTERLY FLOW ASSOCIATED WITH THIS AREA IS  
ALSO DRIVING DRIER AIR INTO CENTRAL CALIFORNIA ALONG WITH  
INCREASED WINDS, ESPECIALLY IN THE LEE SIDE OF THE WEST SIDE  
HILLS AND IN THE MOJAVE DESERT SLOPES. FOR THE LATTER, A HIGH  
WIND WARNING REMAINS IN EFFECT THROUGH 2 AM PDT TOMORROW MORNING  
AS THERE REMAINS A 70 PERCENT CHANCE FOR GUSTS TO EXCEED 55  
MILES PER HOUR. FOR THE SAN JOAQUIN VALLEY, THERE IS A 50 TO 80  
PERCENT CHANCE FOR WIND GUSTS TO EXCEED 30 MILES PER HOUR TODAY.  
A COMBINATION OF THESE WINDS AND MINIMUM RELATIVE HUMIDITY  
VALUES UNDER 20 PERCENT GIVE AN ELEVATED RISK FOR FIRE DANGER  
ACROSS THE VALLEY AREAS TODAY AND MONDAY, WITH THE GREATEST  
THREAT BEING GRASS FIRE POTENTIAL.  
 
ZONAL FLOW-LIKE CONDITIONS ARE ANTICIPATED FOR MONDAY AND  
TUESDAY, WHICH WILL CAUSE A SLIGHT WARMING TREND WITH  
TEMPERATURES IN THE SAN JOAQUIN VALLEY APPROACHING FIVE DEGREES  
ABOVE AVERAGE. RELATIVE HUMIDITY WILL LARGELY HOLD STEADY AROUND  
20 PERCENT OVER THE NEXT FEW DAYS, BUT WITH WINDS DECREASING AS  
THE TROUGH PROGRESSES EASTWARD. A SLOW-BUILDING RIDGE IS  
EXPECTED TO PUSH INTO CENTRAL CALIFORNIA FOR WEDNESDAY AND  
THURSDAY, WHICH WILL WARM TEMPERATURES FURTHER AND DROP MINIMUM  
RELATIVE HUMIDITY VALUES BELOW 15 PERCENT. THERE IS A 50 TO 80  
PERCENT CHANCE FOR AFTERNOON HIGHS TO EXCEED 95 DEGREES BOTH  
DAYS ACROSS MUCH OF THE SAN JOAQUIN VALLEY.  
 
A SLIGHT TROUGHING PATTERN IF FAVORABLE TO PASS THROUGH THE  
REGION FRIDAY INTO THE WEEKEND WHICH WILL RESULT IN A SLIGHT  
COOLING TREND AND SUBSEQUENT INCREASE IN RELATIVE HUMIDITY,  
HOWEVER MIN RH VALUES ARE STILL LIKELY TO REMAIN BELOW 20  
PERCENT THROUGH THE WEEKEND.  
 
 
 
   
AVIATION  
 
6Z UPDATE  
WESTERLY WINDS WILL CONTINUE TO BE STRONG THROUGH 09Z ALONG THE  
MOJAVE DESERT SLOPES WITH GUSTS AROUND 40 KTS. OTHERWISE, VFR  
CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS ACROSS THE CENTRAL  
CALIFORNIA INTERIOR.  
 
 
   
AIR QUALITY ISSUES  
 
ISSUED: 05/18/2025 13:16  
EXPIRES: 05/19/2025 23:59  
NONE.  
 
 
 
CERTAINTY...  
 
THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS HIGH.  
THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS MEDIUM.  
 
CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT  
WWW.WEATHER.GOV/HNX/CERTAINTY.HTML FOR ADDITIONAL INFORMATION  
AND/OR TO PROVIDE FEEDBACK.  
 
 
 
 
   
HNX WATCHES/WARNINGS/ADVISORIES  
 
HIGH WIND WARNING UNTIL 2 AM PDT MONDAY FOR CAZ338.  
 
 
 
 
PUBLIC...SM  
AVIATION....JPK  
 
WEATHER.GOV/HANFORD  
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