513  
FXUS66 KHNX 200504  
AFDHNX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE HANFORD CA  
1004 PM PDT MON MAY 19 2025  
   
UPDATE
 
 
AVIATION SECTION UPDATED  
 

 
 

 
   
KEY MESSAGES
 
 
1. ELEVATED FIRE WEATHER CONDITIONS WILL BE PRESENT TODAY ALONG  
THE WEST SIDE HILLS AND WESTERN SAN JOAQUIN VALLEY DUE TO LOW  
RELATIVE HUMIDITY VALUES AND INCREASED WINDS.  
 
2. ABOVE AVERAGE TEMPERATURES RETURN TODAY AND WILL WARM THROUGH  
THE WEEK. MODERATE HEAT RISK IS EXPECTED ACROSS THE SAN JOAQUIN  
VALLEY ON WEDNESDAY.  
 
3. THERE IS A 50 TO 80 PERCENT CHANCE FOR WIND GUSTS GREATER  
THAN 50 MPH IN THE MOJAVE DESERT SLOPES ON THURSDAY.  
 

 
   
DISCUSSION
 
 
AN UPPER LEVEL TROUGH THAT PASSED THROUGH CENTRAL CALIFORNIA  
OVER THE WEEKEND IS CONTINUING TO PROGRESS EASTWARD THIS  
MORNING, RESULTING IN THE PREVAILING FLOW OVER OUR REGION  
TRACKING OUT OF THE NORTHWEST. AS THE TROUGH CONTINUES FURTHER  
EASTWARD INTO THE CONTIGUOUS UNITED STATES, A ZONAL PATTERN WILL  
SET UP OVER THE WEST, WITH WEAKER WINDS ALOFT ONLY APPROACHING  
20 TO 25 KNOTS. THIS ZONAL PATTERN NORMALLY RESULTS IN  
TEMPERATURES NEAR AVERAGE; HOWEVER, THE DECREASE IN WINDS ALOFT  
WILL CREATE MORE STAGNANT CONDITIONS, AND WILL RESULT IN  
TEMPERATURES A FEW DEGREES ABOVE AVERAGE ACROSS THE AREA. THIS  
PATTERN IS ESPECIALLY PREVALENT ON WEDNESDAY, WHEN AFTERNOON  
HIGHS ARE EXPECTED TO APPROACH TEN DEGREES ABOVE NORMAL. THERE  
IS A 60 TO 80 PERCENT CHANCE FOR TEMPERATURES TO EXCEED 93  
DEGREES ACROSS THE SAN JOAQUIN VALLEY ON WEDNESDAY.  
 
RECENT ENSEMBLE RUNS SHOW A SERIES OF TWO SHORTWAVE UPPER LEVEL  
TROUGHS QUICKLY PASSING THROUGH THE PACIFIC NORTHWEST REGION ON  
THURSDAY AND FRIDAY, WHICH WILL BRING A COOLING TREND TO  
CENTRAL CALIFORNIA AS WINDS INCREASE OFF THE PACIFIC OCEAN.  
HOWEVER, THIS BEING SAID, TEMPERATURES CONTINUE TO BE EXPECTED  
ABOVE NORMAL.  
 
WHILE TEMPERATURES GRADUALLY INCREASE THROUGH THE REST OF THIS  
WEEK, DEW POINT TEMPERATURES WILL HOLD STEADY OR FALL BY A FEW  
DEGREES (DEPENDING ON LOCATION). CURRENT RELATIVE MINIMUM  
RELATIVE HUMIDITY VALUES HOVERING NEAR 20 PERCENT ARE EXPECTED  
TO FALL BELOW 15 PERCENT AS TEMPERATURES INCREASE ON WEDNESDAY  
AND THURSDAY. THESE LOWER RH VALUES CREATE A MORE FAVORABLE  
ENVIRONMENT FOR FIRE DEVELOPMENT IN AREAS OF FINE FUELS, SUCH AS  
GRASSES IN THE SAN JOAQUIN VALLEY. THE ADDITION OF WIND GUSTS  
NEAR 20 MILES PER HOUR IN THE SAN JOAQUIN VALLEY RESULTING FROM  
THE SHORTWAVE TROUGH ON THURSDAY GIVE AN INCREASED RISK FOR FIRE  
DANGER, AS NEW FIRES MAY BE ABLE TO SPREAD MORE QUICKLY.  
 
ENSEMBLE GUIDANCE ISN’T TOO KEEN ON A PARTICULAR SOLUTION FOR  
NEXT WEEKEND, LEADING TO SOME UNCERTAINTY FOR THE CONDITIONS FOR  
THE TIME FRAME. THE MOST COMMON SOLUTION IS FOR A RIDGING  
PATTERN TO BUILD IN, RESULTING IN WARMING TEMPERATURES. THIS IS  
ALSO NOTED BY THE CLIMATE PREDICTION CENTER WHICH GIVES A 40 TO  
50 PERCENT CHANCE FOR ABOVE NORMAL TEMPERATURES FOR OUR REGION  
IN THE 6 TO 10 DAY PERIOD.  
 

 
 
   
AVIATION
 
 
06Z UPDATE  
THERE IS A 60 TO 80 PERCENT CHANCE FOR 30 MPH WIND GUSTS IN THE  
MOJAVE DESERT SLOPES THROUGH 12Z TUE. OTHERWISE, VFR CONDITIONS  
WILL PREVAIL FOR THE NEXT 24 HOURS ACROSS THE CENTRAL  
CALIFORNIA INTERIOR.  
 

 
   
AIR QUALITY ISSUES
 
 
ISSUED: 05/19/2025 14:38  
EXPIRES: 05/20/2025 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
 
 
NONE.  

 
 

 
 
PUBLIC...MOLINA  
AVIATION....JPK  
 
WEATHER.GOV/HANFORD  
 
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