589
FXUS66 KHNX 210608
AFDHNX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HANFORD CA
1108 PM PDT MON APR 20 2026
KEY MESSAGES
1. WINTER STORM WARNING IN EFFECT FOR THE SIERRA NEVADA ABOVE
7,000 FT.
2. AN APPROACHING CUT-OFF LOW BRINGS PERIODS OF HEAVY RAINFALL
AND MOUNTAIN SNOW BY EARLY TUESDAY, WITH FAVORABLE CONDITIONS
FOR CONVECTIVE WEATHER AFTERWARDS.
DISCUSSION
A LARGE BAND OF STRATIFORM RAIN HAS BEEN MOVING INTO NORTHERN
CALIFORNIA FROM THE SOUTHWEST FOR THE PAST FEW HOURS, AND IT
WILL SOON SHIFT COURSE AND MOVE OVER OUR CWA, LIKELY BY MIDNIGHT
TONIGHT. PRECIPITATION IN THE FOOTHILLS AND UPPER SIERRA NEVADA
CAN BE EXPECTED TO START AROUND 5AM AND THE REST OF OUR CWA WILL
START TO SEE RAINFALL BY 11AM TOMORROW MORNING. WIDESPREAD
RAINFALL IS EXPECTED THROUGH AT LEAST 5PM FOR THE SIERRA NEVADA
AND ITS FOOTHILLS. CURRENT PROBABILITIES FOR AN INCH OF RAINFALL
IN THE FOOTHILLS NORTH OF KINGS CANYON ARE 60-80% FOR THE 24
HOUR PERIOD ENDING TUESDAY AT 11PM. THERE IS ALSO A MARGINAL
RISK (AT LEAST 5%) FOR EXCESSIVE RAINFALL IN THAT AREA, ALONG
WITH THE SAN JOAQUIN VALLEY FROM VISALIA TO LOS BANOS AS THE
CROW FLIES.
FOR THE SIERRA NEVADA, HEAVY SNOW IS EXPECTED ABOVE 7000 FEET,
WITH TOTALS OF 3 TO 5 INCHES ABOVE THAT ELEVATION AND 12 TO 18
INCHES AT THE HIGHEST ELEVATIONS, MAINLY AROUND YOSEMITE NP. DUE
TO THIS, A WINTER STORM WARNING HAS BEEN ISSUED FOR THE SIERRA
NEVADA MOUNTAINS FROM SEQUOIA NP NORTHWARDS FROM 2AM TUESDAY
MORNING THROUGH 5PM WEDNESDAY AFTERNOON. ALONG WITH THIS HEAVY
SNOW, STRONG WIND GUSTS OF 75 MPH OR HIGHER ARE ALSO EXPECTED
WITH THIS SYSTEM, AND NOT JUST FOR THE SIERRA NEVADA. THERE IS A
40-60% CHANCE OF 64 MPH GUSTS OR HIGHER ALONG THE MOJAVE DESERT
SLOPES AND SIMILAR CHANCES FOR 55 MPH GUSTS IN THE MOJAVE
DESERT ITSELF ON TUESDAY AS WELL. A WIND ADVISORY HAS BEEN
ISSUED FOR BOTH OF THESE REGIONS, THE ADVISORY ON THE SLOPES
LASTING UNTIL 8PM TOMORROW NIGHT, AND THE ADVISORY ON THE DESERT
EXPIRING EARLIER AT 7AM ON TUESDAY.
AS THE MAIN RAIN BAND MOVES THROUGH THE REGION TUESDAY
AFTERNOON, THE CHANCES FOR THUNDERSTORMS INCREASES INTO THE 30 TO
45% RANGE IN THE VALLEY FROM PORTERVILLE NORTH. THE SOUTHERN
HALF OF THE VALLEY CAN EXPECT A 15-30% CHANCE OF THUNDERSTORMS.
THIS IS DUE TO THE INCREASED DYNAMICS BEHIND THE INITIAL WAVE
COMBINED WITH THE NEWLY FALLEN MOISTURE AND AFTERNOON HEATING.
AS OF TODAY, THE STORM PREDICTION CENTER HAS PUT THIS AREA UNDER
A GENERAL RISK FOR THUNDERSTORMS. SEVERE THUNDERSTORMS ARE NOT
EXPECTED. HOWEVER, ANY CELL THAT FORMS STILL COMES WITH THE RISK
FOR SMALL HAIL, FREQUENT LIGHTNING, GUSTY WINDS, AND LOCALIZED
FLOODING.
AFTER THIS SYSTEM MOVES EAST AND THE PRECIPITATION MOVES ON,
A WEAK TROUGH MAY STILL HANG AROUND ALOFT, WITH CURRENT
ENSEMBLE MODELS CONTINUING TO AGREE WITH THAT FORECAST. A
SECOND, ALBEIT WEAKER, CUT-OFF LOW MAY DEVELOP LATER THIS WEEK
AND PRODUCE SOME PRECIPITATION BY THE WEEKEND, PARTICULARLY IN
THE SIERRA NEVADA. THIS WEAK TROUGH WILL ALSO KEEP TEMPERATURES
AROUND NORMAL THROUGH THE WEEKEND.
AVIATION
VFR CONDITIONS EXPECTED ACROSS THE AREA FOR THE NEXT 24 HOURS,
WITH MVFR CONDITIONS IN AND AROUND THUNDERSTORMS FROM ABOUT 18Z
TUESDAY THROUGH 06Z WEDNESDAY.
AIR QUALITY ISSUES
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
WIND ADVISORY FROM 2 PM TUESDAY TO 8 PM PDT WEDNESDAY FOR
CAZ338.
WINTER STORM WARNING FROM 2 AM TUESDAY TO 5 PM PDT WEDNESDAY
FOR CAZ323-326>328-330.
WIND ADVISORY FROM 2 PM TUESDAY TO 7 AM PDT WEDNESDAY FOR
CAZ337-339.
EW
WEATHER.GOV/HANFORD
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