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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