000
FXUS66 KHNX 032242
AFDHNX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
242 PM PST WED DEC 3 2008
.DISCUSSION...STRATUS CONTINUES TO BLANKET THE SAN JOAQUIN VALLEY
AND LOWER FOOTHILLS THIS AFTERNOON. VISIBLE SATELLITE PICTURES ARE
STARTING TO SHOW A LITTLE CLEARING AROUND THE EDGES...BUT IT IS
HARD TO TELL HOW MUCH THE STRATUS IS THINNING DUE TO CIRRUS CLOUDS
MOVING OVERHEAD. EVEN WITH A LITTLE MORE CLEARING...EXPECT STRATUS
AND PATCHY FOG ACROSS THE VALLEY TONIGHT AND INTO THURSDAY.
THE NEXT APPROACHING TROUGH WILL CROSS THE REGION THURSDAY. THIS
SYSTEM HAS TWO PARTS TO IT...THE FIRST BEING THE CLOSED UPPER LOW
OFF THE PACIFIC NORTHWEST COAST THAT WILL DROP SOUTH AND REMAIN
OFF THE COAST OF CALIFORNIA THURSDAY...AND THE SECOND PART THAT IS
A SHORTWAVE THAT WILL DROP SOUTH THROUGH THE GREAT
BASIN...DRAGGING THE TAIL END OF THE SHORTWAVE THROUGH CENTRAL
CALIFORNIA. THIS WILL LOWER HEIGHTS SLIGHTLY AND BRINGING A MORE
NORTH TO NORTHEASTERLY FLOW ALOFT THURSDAY AFTERNOON INTO FRIDAY.
IF THE STRATUS DOES INDEED THIN MORE TODAY...THERE COULD BE ENOUGH
UPPER LEVEL ENERGY MOVING THROUGH WITH THIS SYSTEM TO HELP MIX OUT
THE STRATUS DECK IN THE VALLEY...BUT LIKELY WILL NOT SEE IT
TOTALLY CLEAR. THIS SYSTEM WILL ALSO BRING SLIGHT COOLING OVER THE
DISTRICT EXCEPT IN THE VALLEY WHERE TEMPERATURES WILL LIKELY BE A
BIT IF THE STRATUS CLEARS. IF THE STRATUS DOES CLEAR...EVEN ONLY
PARTIALLY...WE WILL LIKELY SEE A RETURN TO LOW STRATUS AND PATCHY
FOG THURSDAY NIGHT.
ALL OF THE EXTENDED FORECAST MODELS CHANGED THEIR IDEA OF WHAT
HAPPENS WITH THE UPPER LOW OFF THE COAST THIS WEEKEND. THE MODELS
NOW AGREE THAT THE LOW WILL STAY WELL OFFSHORE WELL INTO NEXT
WEEK...WITH THE ECMWF BEING THE CLOSEST TO THE COAST...BUT NOT
CLOSE ENOUGH TO BRING ANY PRECIPITATION. THE GFS SOLUTION WOULD
LEAVE STRONGER HIGH PRESSURE OVER CENTRAL CALIFORNIA THAN THE
ECMWF. IF WE CAN NOT GET SOME DRIER AIR INTO THE VALLEY THURSDAY
AND FRIDAY...THIS COULD KEEP THE SAN JOAQUIN VALLEY IN A FOG AND
STRATUS PATTERN FOR A WHILE LONGER. TEMPERATURES SHOULD NOT
CHANGE SIGNIFICANTLY DURING THE PERIOD.
&&
.AVIATION...IN THE CENTRAL AND SOUTH SAN JOAQUIN VALLEY AND THE
SOUTHERN SIERRA NEVADA FOOTHILLS...AREAS OF MVFR IN MIST AND
STRATUS THROUGH 06Z THURSDAY...BECOMING AREAS IFR IN MIST AND
STRATUS WITH LCL LIFR IN FOG THROUGH 18Z THURSDAY. WIDESPREAD MVFR
IN HAZE WITH AREAS MVFR CIGS IN STRATUS FROM 18Z THURSDAY TO 00Z
FRIDAY. ACROSS THE REMAINDER OF THE CENTRAL CA INTERIOR...VFR THRU
00Z FRIDAY.
&&
.AIR QUALITY ISSUES...
NONE
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
PUBLIC...BEAN
AVN/FW...DCH
WEATHER.GOV/HANFORD
