338
FXUS66 KHNX 131745
AFDHNX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HANFORD CA
1045 AM PDT THU AUG 13 2026
KEY MESSAGES
1. POTENTIAL FOR THUNDERSTORMS ACROSS THE AREA
AGAIN, RANGING FROM 5 TO 10% IN THE SAN JOAQUIN VALLEY AND
MOJAVE DESERT UP TO 40% ALONG THE SIERRA NEVADA CREST.
2. THREAT OF DAMAGING WIND FROM STRONG THUNDERSTORMS.
3. ISOLATED DRY LIGHTNING PRESENTS ELEVATED FIRE RISK TODAY FOR
SIERRA NEVADAS.
4. LAKE WIND ADVISORY FOR SAN LUIS RESERVOIR FROM 5PM THIS
AFTERNOON UNTIL 2AM FRIDAY MORNING.
DISCUSSION
MORNING GUIDANCE INDICATES OUR AREA IS BOOKED FOR ONE MORE DAY
OF MONSOON MOISTURE AS THE TROUGH OFF THE CALIFORNIA COAST
PUSHES INLAND TODAY. COMPARED TO THE MORE REGION- WIDE EVENTS
YESTERDAY AND TUESDAY, TODAY'S PRIMARY THREAT WILL BE ALONG THE
SIERRA NEVADA CREST AND DOWNWIND INTO THE GREAT BASIN. THE
LATEST PROBABILISTIC RUN FROM THE NATIONAL BLEND OF MODELS (NBM)
PLACES THE SIERRA CREST UNDER A 30-40% PROBABILITY FOR
THUNDERSTORMS WITH 20-25% PROBABILITY DOWN TO AROUND 2,000-3,000
FEET.
THE MAIN WEATHER THREAT ASSOCIATED WITH TODAY'S THUNDERSTORMS
IS LIGHTNING- INITIATED FIRES AND BRIEF DAMAGING GUSTS IN THE
SIERRA NEVADAS. THE SOUTHWESTERLY FLOW TRANSFERRING
PRECIPITABLE WATER (PWAT) INTO OUR AREA IS NOTICEABLY WEAKER
COMPARED TO THE PAST COUPLE DAYS, INDICATIVE OF LOWER
PROBABILITY FOR THUNDERSTORMS ALONG THE COASTAL RANGE, THE SAN
JOAQUIN VALLEY, AND MOJAVE DESERT. AMONGST THESE AREAS, SHORT-
TERM ENSEMBLE GUIDANCE AND THE NBM ARE IN GOOD AGREEMENT THE
FRIENDLY TROUGH WILL HASTEN WINDS THROUGH PACHECO PASS LATER
THIS AFTERNOON. THUS, A LAKE WIND ADVISORY FOR SAN LUIS
RESERVOIR IS SET TO BE IN EFFECT FROM 5PM THIS AFTERNOON UNTIL
2AM FRIDAY.
BY FRIDAY AFTERNOON, A TRANSITION TO MORE NEUTRAL FLOW WILL
SIGNIFICANTLY DECREASE THE PROBABILITY FOR THUNDERSTORMS IN THE
SIERRA NEVADA, AND WILL CALM WINDS ACROSS THE COASTAL RANGE
MOUNTAIN PASSES. THE ENTIRE FORECAST AREA LOOKS SET FOR
A PLEASANT WEEKEND, WITH SAN JOAQUIN VALLEY HIGHS IN THE UPPER
80S TO LOW 90S AND MID-TO-UPPER 90S IN THE MOJAVE DESERT. A
SLIGHT WARMUP IS EXPECTED LATER NEXT WEEK AS THE REGION COMES
UNDER THE INFLUENCE OF HIGH PRESSURE.
AVIATION...
VFR CONDITIONS PREVAILING FOR SAN JOAQUIN VALLEY (SJV).
SCATTERED TO BROKEN CLOUD COVER ABOVE 10,000 FEET ALONG
FOOTHILLS OF EASTERN SJV, SIERRA NEVADA, AND KERN COUNTY DESERT
AND SLOPES. REGION WIDE THREAT OF THUNDERSTORMS, WITH GREATEST
PROBABILITY (30-40%) ALONG THE SIERRA NEVADA CREST UNTIL 03Z
THURSDAY. LOWER (5-10%) PROBABILITIES IN THE MOJAVE DESERT AND
SAN JOAQUIN VALLEY. MVFR TO HIGH-END IFR CONDITIONS POSSIBLE
WITHIN THUNDERSTORMS FROM DECREASED VISIBILITY AND CLOUD
CEILINGS.
FIRE WEATHER
LATEST STORM PREDICTION CENTER (SPC) CONVECTIVE OUTLOOK
HIGHLIGHTS THE SIERRA NEVADAS OF MADERA COUNTY AND NORTHWARD AS
UNDER AN ISOLATED RISK OF DRY LIGHTNING STRIKES. COMBINED WITH
CURED FUELS, ANY LIGHTNING STRIKES OUTSIDE THUNDERSTORM
PRECIPITATION CORES HAVE A HIGH PROBABILITY OF INITIATING NEW FIRES.
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
LAKE WIND ADVISORY FROM 5
PM THIS AFTERNOON TO 2 AM PDT FRIDAY FOR CAZ300.
PUBLIC...DAER
AVIATION....MCCOY
WEATHER.GOV/HANFORD
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