165
FXUS66 KHNX 080917
AFDHNX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HANFORD CA
217 AM PDT WED OCT 8 2025
KEY MESSAGES
1. A LOW PRESSURE SYSTEM WILL BRING CHANCES FOR PRECIPITATION
TO THE AREA THURSDAY THROUGH SATURDAY. THERE IS A 20 TO 30
PERCENT PROBABILITY FOR MEASURABLE RAINFALL IN THE DESERT AREAS
FRIDAY WITH LESSER CHANCES FOR THE VALLEY AND MOUNTAIN AREAS.
2. TROPICAL MOISTURE FROM THE SOUTH WILL RESULT IN A 10 TO 20
PERCENT PROBABILITY FOR THUNDERSTORMS IN THE KERN DESERT
THURSDAY AND FRIDAY.
3. MAXIMUM WIND GUSTS ALONG THE CRESTS OF THE SIERRA HAVE A 50
TO 60 PERCENT PROBABILITY TO EXCEED 40 MPH THURSDAY AND FRIDAY.
4. POTENTIAL FOR A DEEPER SYSTEM TO DEVELOP INTO NEXT WEEK, WITH
WIDESPREAD 40 TO 50 PERCENT PROBABILITIES FOR 0.1" OR GREATER OF
PRECIPITATION TUESDAY.
DISCUSSION
SEASONABLE CONDITIONS ARE EXPECTED TODAY AFTER A CUTOFF LOW
PRESSURE SYSTEM HAS WEAKENED AND PHASED WITH A LOW PRESSURE
TROUGH CURRENTLY LOCATED OVER THE PACIFIC NORTHWEST. UPPER LEVEL
FLOW OVER CENTRAL CALIFORNIA WILL BE FROM THE SOUTHWEST TODAY,
BUT WITH WEAKER WINDS ALOFT THERE WILL NOT BE A LARGE DEVIATION
FROM SEASON AVERAGE TEMPERATURES FOR THIS TIME OF YEAR. A
COOLING TREND WILL BEGIN TOMORROW AS THE AFOREMENTIONED TROUGH
CUTS OFF FROM THE MAIN ATMOSPHERIC FLOW, SLOWLY TRACKING SOUTH
AS A LOW PRESSURE SYSTEM. WHILE THIS SYSTEM DIPS SOUTH,
HURRICANE PRISCILLA IS PROJECTED TO SLOWLY MOVE NORTHWARDS ALONG
THE COAST OF BAJA CALIFORNIA. AS STATED IN PREVIOUS DISCUSSIONS,
THE APPROACHING CUTOFF LOW WILL PUSH THE TROPICAL MOISTURE
ASSOCIATED WITH PRISCILLA INTO THE DESERT SOUTHWEST. HOWEVER
ENSEMBLE GUIDANCE IS SUGGESTING SOME OF THIS MOISTURE WILL
TRACK OVER A PORTION OF THE MOJAVE DESERT, RESULTING IN A 10 TO
20 PERCENT PROBABILITY FOR THUNDERSTORMS IN THIS AREA THURSDAY
AND FRIDAY. THERE HAS BEEN A DOWNTREND IN EXPECTED MOISTURE OVER
THE VALLEY AND MOUNTAIN AREAS, AS ENSEMBLES NOW EXPRESS LESS
THAN A 20 PERCENT PROBABILITY FOR MEASUREABLE RAINFALL. IN
ADDITION TO THE PRECIPITATION AND THUNDERSTORM POTENTIAL, THE
UPCOMING SYSTEM HAS A 50 TO 60 PERCENT PROBABILITY FOR WIND
GUSTS GREATER THAN 40 MPH OVER THE SIERRA CRESTS THURSDAY AND
FRIDAY.
COOLER TEMPERATURES IN THE MID 70S, UP TO TEN DEGREES BELOW
SEASON AVERAGES LOOK IN STORE FOR THE WEEKEND AS UPPER LEVEL
FLOW SHIFTS TO THE NORTHWEST ON THE BACKSIDE OF THE SYSTEM.
HOWEVER, AS WE GET INTO THE EARLY PORTION OF NEXT WEEK, CLUSTER
ANALYSIS IS EXPRESSING POTENTIAL FOR A MORE ROBUST LOW PRESSURE
SYSTEM TO DROP SOUTH FROM THE GULF OF ALASKA. WHILE THERE IS
SOME DISAGREEMENT IN EXACT LOCATION AMONG THE MODELS, THERE IS A
GENERAL CONSENSUS THAT THIS POTENTIAL SYSTEM WILL TRACK FURTHER
SOUTH THAN THIS WEEK'S SYSTEM, TRAINING MORE MOISTURE OVER
CENTRAL CALIFORNIA. AS OF THIS DISCUSSION, ENSEMBLES HINT AT A
40 TO 50 PERCENT PROBABILITY FOR 0.1" OR MORE OF PRECIPITATION
OVER THE MUCH OF THE REGION NEXT TUESDAY. AS THIS SYSTEM WILL BE
ANOTHER COLD-BASED SYSTEM, THERE IS A 40 TO 50 PERCENT
PROBABILITY FOR HALF A FOOT OR MORE OF SNOWFALL FOR THE CENTRAL
SIERRA ABOVE 8000 FEET.
AVIATION
VFR CONDITIONS ARE EXPECTED THROUGH 00Z 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
NONE.
PUBLIC/AVIATION...MCCOY
WEATHER.GOV/HANFORD
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