616  
FXUS66 KHNX 180440  
AFDHNX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE HANFORD CA  
940 PM PDT SAT MAY 17 2025  
   
UPDATE
 
 
AVIATION SECTION UPDATED  
 

 
 

 
   
KEY MESSAGES
 
 
1. A COOLDOWN OCCURS THIS WEEKEND, WITH GUSTY WINDS BY SATURDAY  
AFTERNOON OVER THE MOUNTAIN RIDGES AND PEAKS, AS WELL AS THE  
KERN COUNTY DESERT. ELSEWHERE, WINDS WILL BE NOTICEABLY  
STRONGER.  
 
2. A 10-15 PERCENT CHANCE OF AFTERNOON AND EVENING  
THUNDERSTORMS EXISTS IN THE SIERRA NEVADA TODAY.  
 
3. INCREASED WINDS COMBINED WITH LOW HUMIDITY ON SUNDAY AND  
MONDAY WILL LEAD TO A RISK FOR LARGE GRASS FIRES IN THE SAN  
JOAQUIN VALLEY.  
 
4. WELL ABOVE NORMAL TEMPERATURES AND MAINLY DRY CONDITIONS ARE  
EXPECTED TUESDAY AND THE REMAINDER OF NEXT WEEK.  
 

 
   
DISCUSSION
 
 
SATELLITE LOOPS SHOW MAINLY MID-LEVEL AND HIGH CLOUDS DUE TO AN  
UPPER-LEVEL TROUGH OVER THE WFO HANFORD WARNING/FORECAST AREA.  
NOTICEABLY COOLER TEMPERATURES AND STRONGER WINDS WILL TAKE  
PLACE TODAY AND SUNDAY AS THE TROUGH CONTINUES ITS TREK OVER THE  
GREAT BASIN. MUCH OF THE MOISTURE AND DYNAMICS HAS BEEN PASSING  
TO OUR NORTH, ALTHOUGH A SLIGHT CHANCE OF THUNDERSTORMS IS  
FORECAST FOR THE SIERRA NEVADA, THOUGH MAINLY IN THE HIGHER  
ELEVATIONS. THE CHANCES FOR THUNDERSTORMS TODAY ARE AROUND 10-15  
PERCENT. FORECAST PRECIPITATION AMOUNTS ARE LIGHT, OR UP TO A  
FEW HUNDREDTHS OF AN INCH WITH A DUSTING OF SNOW OVER THE  
HIGHEST ELEVATIONS. STRONG AND GUSTY WINDS DEVELOP LATER TODAY  
IN THE KERN COUNTY DESERT AND OVER THE RIDGES AND PEAKS ALONG  
THE SIERRA NEVADA CREST, WITH THE HIGHEST IMPACTS LIKELY AT THE  
MOJAVE DESERT SLOPES (INCLUDING MOJAVE). THE PROBABILITY FOR A  
GUST OF AT LEAST 55 MPH IS 75-95 PERCENT ALONG THE MOJAVE DESERT  
SLOPES AND NEARBY AREAS JUST BELOW, WITH THE PEAK STRENGTH  
DURING THIS EVENING. IN ADDITION, THE RISK, WHILE RELATIVELY  
LOW, FOR LARGE GRASS FIRES EXISTS IN THE CENTRAL VALLEY ON  
SUNDAY DUE TO THE COMBINATION OF LOWER HUMIDITY WITH BREEZY  
CONDITIONS REDEVELOPING. WINDS ON MONDAY WON'T BE QUITE AS  
STRONG, BUT THE TEMPERATURES WILL BE WARMER THAN ON SUNDAY AND  
WILL KEEP DAYTIME HUMIDITY LOW. SO, THE POSSIBILITY FOR MONDAY  
WILL REMAIN.  
 
ENJOY THE MILD, MORE SPRING-LIKE TEMPERATURES THIS WEEKEND, AS  
A LONGER PERIOD OF ABOVE AVERAGE TEMPERATURES COMMENCES EARLY  
NEXT WEEK. A RIDGE OF HIGH PRESSURE WILL BUILD AND REMAIN  
ANCHORED OVER MUCH OF THE SOUTHWESTERN U.S. FROM MONDAY AND THE  
REST OF NEXT WEEK. MONDAY'S HIGHS WILL BE SLIGHTLY ABOVE  
AVERAGE, BUT THE WARMING WILL BECOME MORE NOTICEABLE BY TUESDAY.  
PROBABILITIES FOR HIGHS IN THE 90'S IN THE WARMEST LOCATIONS  
ARE AT A MINIMUM OF 70 TO 90 PERCENT FOR TUESDAY UNTIL AT LEAST  
THE NEXT FEW DAYS. TRIPLE DIGIT HEAT BECOMES A POSSIBILITY ONCE  
AGAIN BY THURSDAY, INCLUDING IN BOTH THE SJ VALLEY AND KERN  
COUNTY DESERT, OR AT 20-40 PERCENT CHANCE. OTHER LOCATIONS  
BESIDES KERN COUNTY COULD SEE THEIR FIRST TRIPLE DIGIT DAY FOR  
THIS YEAR BY THEN. WHILE PROBABILITIES FOR TRIPLE DIGIT READINGS  
ARE A BIT LOWER FOR NEXT FRIDAY (ABOUT 10-25%, WITH THE BEST  
CHANCES IN THE DESERT), SUMMER-LIKE TEMPERATURES COULD PERSIST  
FOR A LITTLE WHILE BASED ON THE LATEST 6-10 AND 8-14 DAY  
OUTLOOKS FROM THE CLIMATE PREDICTION CENTER, WITH A PROBABILITY  
OF ABOVE 50 TO 60 PERCENT OF ABOVE AVERAGE TEMPERATURES FOR THE  
LATEST 6-10 DAY OUTLOOK AND ABOUT 35-40 PERCENT CHANCE ON THE  
8-14 DAY OUTLOOK.  
 

 
   
AVIATION
 
 
00Z UPDATE:  
 
MVFR WITH LOCAL IFR IN MOUNTAIN OBSCURATIONS POSSIBLE OVER THE  
SIERRA NEVADA, FROM YOSEMITE NP TO SEQUOIA NP, DUE TO A SLIGHT  
CHANCE (AROUND 15 PERCENT) SHOWERS/THUNDERSTORMS THROUGH 06Z  
SUNDAY. WESTERLY WINDS WILL CONTINUE TO BE STRONG THROUGH 09Z  
SUNDAY IN THE KERN COUNTY DESERT AND ADJACENT SLOPES WITH GUSTS  
45-55 KTS. OTHERWISE, VFR CONDITIONS WILL PREVAIL FOR THE NEXT  
24 HOURS ACROSS THE CENTRAL CALIFORNIA INTERIOR.  
 

 
 
   
AVIATION
 
 
6Z UPDATE:  
 
WESTERLY WINDS WILL CONTINUE TO BE STRONG THROUGH 09Z SUNDAY IN  
THE KERN COUNTY DESERT AND ADJACENT SLOPES WITH GUSTS 45-55  
KTS. OTHERWISE, VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24  
HOURS ACROSS THE CENTRAL CALIFORNIA INTERIOR.  
 

 
   
AIR QUALITY ISSUES
 
 
ISSUED: 05/17/2025 12:53  
EXPIRES: 05/18/2025 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.  
WIND ADVISORY UNTIL 2 AM PDT SUNDAY FOR CAZ337-339.  

 
 

 
 
PUBLIC...BSO/EW  
AVIATION....JPK  
 
WEATHER.GOV/HANFORD  
 
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