EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
AFDSAN 200 PM PST TUE JAN 22 2002
.SYNOPSIS...A TROUGH OF LOW PRESSURE OVER THE SOUTHWEST WILL
CONTINUE THE COOL BREEZY CONDITIONS THROUGH TONIGHT ALONG WITH A
SLIGHT CHANCE OF LIGHT SHOWERS ALONG AND WEST OF THE MOUNTAINS. THE
TROUGH WILL MOVE EAST ON WEDNESDAY AS AN OFFSHORE FLOW
DEVELOPS...WEAKENING ON THURSDAY. MOSTLY CLEAR WITH WARMER DAYS
THURSDAY AND FRIDAY. ANOTHER TROUGH WILL MOVE IN OVER THE WEEKEND
BRINGING A CHANCE OF SHOWERS.
.DISCUSSION...MARINE LAYER REMAINS AROUND 6000 FEET OVER THE CWFA
THIS AFTERNOON BASED ON PILOT REPORT OF TOPS. SATELLITE IMAGERY
SHOWS AN EDDY CIRCULATION ABOUT 15 MILES OFF THE COAST OF LA JOLLA.
SOME ISOLATED SPRINKLES CONTINUE BUT NO REPORTS OF ANY MEASURABLE
PRECIPITATION SO FAR.
PILOT REPORT FROM AN AIRCRAFT DESCENDING INTO PALM SPRINGS THROUGH
THE BANNING PASS REPORTED WEST WIND TO 50 KNOTS BETWEEN 4500 AND
1500 FEET AT 2042Z AND KSOX 88D VWP INDICATED WIND IN EXCESS OF 50
KNOTS AT SOME OF THE MOUNTAIN ELEVATION LEVELS SO WILL ISSUED A WAD
FOR THE MOUNTAINS AND APPLE AND YUCCA VALLEY AS WELL AS THE
COACHELLA VALLEY THROUGH 9 PM PST. SEE LAXNPWSAN FOR DETAILS.
12Z MODELS ARE IN FAIRLY GOOD AGREEMENT MOVING THE TROUGH EAST ON
WEDNESDAY AS RIDGING TAKES PLACE ALONG THE COAST. SURFACE HIGH
PRESSURE BUILDS OVER THE GREAT BASIN ON WEDNESDAY WITH A DEVELOPING
OFFSHORE FLOW ACROSS SOUTHERN CALIFORNIA. PATTERN SHOULD PRODUCE
WIND IN THE USUAL SPOTS BELOW THE PASSES AND CANYONS DURING THE DAY
ON WEDNESDAY AND CONTINUING THROUGH WEDNESDAY NIGHT THEN DIMINISHING
ON THURSDAY. LOCAL WIND STUDY SUPPORTS WIND ADVISORY LEVEL WIND FOR
WEDNESDAY INTO THURSDAY SO WILL GO WITH WAD STRENGTH WINDS FOR
WEDNESDAY BUT SINCE THIS WILL BE THE SECOND PERIOD...WILL NOT ISSUE
ANY WAD AT THIS TIME. RIDGE REMAINS IN PLACE THURSDAY AND FRIDAY.
MRF BRINGS ANOTHER TROUGH OVER THE COAST OVER THE WEEKEND AND HANGS
ONTO THIS TROUGH THROUGH EARLY NEXT WEEK. MRF NOW INDICATES SOME QPF
FOR EACH DAY BEGINNING SUNDAY. HOWEVER...CONFIDENCE IS LOW IN THE
AMOUNT OF QPF BUT WILL KEEP A CHANCE OF SHOWERS IN FOR THE EXTENDED
THROUGH TUESDAY.
.SAN...SMALL CRAFT ADVISORY MARINE ZONE PZZ775...(LAXCWFSGX).
WIND ADVISORY FOR ZONES 055 056 060 AND 061...(LAXNPWSAN).
HORTON
EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
AFDSAN 325 AM PST TUE JAN 22 2002
.SYNOPSIS...A DEVELOPING TROUGH OF LOW PRESSURE OVER THE SOUTHWEST
WILL BRING COOLER AND BREEZY CONDITIONS TO SOUTHWEST CALIFORNIA
ALONG WITH A DEEPENING MARINE LAYER. THERE IS A SLIGHT CHANCE OF
LIGHT SHOWERS ALONG AND WEST OF THE MOUNTAINS TONIGHT. AS THE UPPER
TROUGH MOVES EAST...OFFSHORE FLOW WILL DEVELOP WEDNESDAY...WEAKENING
THURSDAY. FAIR AND WARMER THURSDAY AND FRIDAY...THEN COOLER AND
BREEZY WITH A CHANCE OF SHOWERS FOR THE WEEKEND.
.DISCUSSION...MDLS ARE IN GOOD AGREEMENT SYNOPTICALLY THRU THE
EXTENDED. CURRENT MARINE LYR DEPTH IS AROUND 3000 FT WITH RAPID
DEEPENING CONTINUE ALG WITH A WELL-DEFINED EDDY OVR THE CSTL WTRS.
HOWEVER...ACARS SOUNDINGS SHOW THAT IN ADDITION TO THE DEEPENING OF
THE MARINE LYR...THE MARINE INVERSION IS RATHER WK. THIS SHOULD
ALLOW SKIES TO BECOME PARTLY CLOUDY THIS AFTERNOON. DENSE FOG
REMAINS TRAPPED IN THE PERRIS VLY. VISIBILITIES SHOULD GRADUALLY
IMPROVE AFTER DAYBREAK. MDLS SHOW EDDY CIRCULATION DECAYING THIS
AFTERNOON...THEN REDEVELOPING TONIGHT OFF THE SAN COUNTY CST WITH
EXTENSIVE LOW LVL MSTR ALG AND W OF THE MTNS FM LOS ANGELES S. WL
RETAIN A SLIGHT CHANCE OF SHOWERS FOR TONIGHT AS MDLS DROP AN
AMPLIFYING SHORTWAVE SOUTHWARD ACROSS THE SRN CA. INTERACTION OF
THIS SHORTWAVE WITH THE DEEP MARINE LYR ALG AND W OF THE MTNS MAY BE
SUFFICIENT TO GENERATE A FEW LIGHT SHOWERS. AMOUNTS...IF
ANY...SHOULD BE SPOTTY AND LIGHT.
FLOW BECOMES OFFSHORE WED INTO THU WITH PK OFFSHORE FLOW WED. WINDS
MIGHT REACH THE LOW END OF WIND ADV LVLS BLO CAJON PASS AND IN THE
SNA MTNS WITH WINDS WKR WED NIGHT INTO THU MORNING.
SHORTWAVE RDGG DEVELOPS ACROSS SOUTHERN CALIFORNIA THU AND FRI
BRINGING WARMING OF DAYTIME TEMPERATURES THOUGH OVERNIGHT LOWS WL
REMAIN QUITE COOL. MOSTLY CLOUDY...BREEZY...AND COOLER FOR SAT THRU
MON WITH A CHANCE OF LIGHT RAIN (SHOWERS MTNS) AS A TROUGH OF LOW
PRESSURE AMPLIFIES ALG THE W CST.
.SAN...NONE.
MARTIN