EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
AFDSAN 330 AM PST SAT JAN 12 2002
.SYNOPSIS...HIGH PRESSURE IS BEGINNING TO WEAKEN AND SHIFT WESTWARD.
FAIR WEATHER AND MILD TEMPERATURES SHOULD CONTINUE THROUGH THE
REMAINDER OF THE WEEKEND. A SERIES OF UPPER TROUGHS WILL MOVE BY TO
THE NORTH NEXT WEEK. THESE WILL BRING COOLER TEMPERATURES...MORE
CLOUDS AND ONSHORE FLOW TO SOUTHWEST CALIFORNIA. TOWARDS THE END OF
NEXT WEEK...OFFSHORE FLOW MAY RETURN WITH A BRIEF WARMING TREND.
.DISCUSSION...OFFSHORE GRADIENTS ABOUT 3 MB LESS THAN 24 HOURS AGO
AND THOUGH 12/00Z KNKX SOUNDING HAD STRONG NE WINDS...ACARS
SOUNDINGS SINCE 12/06Z SHOW NE WINDS LESS THAN 20 KTS IN LOWER 10000
FEET. HIGHEST WIND GUST IN WIND PRONE AREAS PER RAWS OBS WAS 26 MPH
AROUND MIDNIGHT. UPPER TROUGH PASSING BY TO THE NORTH SHOULD PRODUCE
ADDITIONAL PRESSURE FALLS OVER GREAT BASIN WHICH WILL FURTHER LESSEN
GRADIENTS SO WILL NOT MENTION WINDS IN FIRST PERIOD. THIS MORNINGS
LOW TEMPERATURES LOOK LIKE THEY WILL BE GENERALLY COOLER THAN FRIDAY
DUE TO LESS MIXING. COUPLED WITH MINOR HEIGHT/THICKNESS FALLS
THIS AFTERNOON OF ABOUT 30 METERS...WILL ADJUST TODAYS MAX
TEMPERATURES TO SHOW 3-5 DEGREES COOLING AND CHANGE SKY COVER TO
MOSTLY SUNNY TO ACCOUNT FOR CIRRUS STREAKS BRUSHING AREA. AS FOR
REMAINDER OF FORECAST PERIODS...LATEST RUN OF MODELS ARE IN GOOD
AGREEMENT ON SYNOPTIC PATTERN WITH RIDGE AXIS RETROGRADING TO AROUND
140W LONGITUDE OVER NEXT 7 DAYS. THIS ALLOWS SERIES OF SHORT WAVES
TO DROP SE FROM PACIFIC NORTHWEST INTO CENTRAL CALIFORNIA SUNDAY
THROUGH TUESDAY WITH HEIGHT/THICKNESS FALLS OF ABOUT 60 METERS PER
DAY OVER SW CALIFORNIA...THEN TROUGH AXIS BECOMES QUASI-STATIONARY
JUST NW OF FORECAST AREA WEDNESDAY/THURSDAY...FINALLY PUSHING SOUTH
AND EAST ON FRIDAY WITH RIDGING INTO THE FOLLOWING WEEKEND. THIS
FORECAST SCENARIO SHOULD GIVE SW CALIFORNIA A NOTICEABLE COOLING
TREND/CLOUD INCREASE IN ALL ZONES...WITH ONSHORE FLOW DEEPENING THE
MARINE LAYER WEST OF MOUNTAINS AND ABUNDANT MID/HIGH CLOUDS FROM
PROXIMITY OF UPPER TROUGH AXIS SPREADING ACROSS ENTIRE AREA. WILL
SHOW ABOUT 5 DEGREES COOLING PER DAY THROUGH TUESDAY...REGROUP
DAYS 4 THROUGH 7 TO HAVE PARTLY CLOUDY THROUGH THURSDAY...AND
BREAK FRIDAY OUT TO SHOW CLEARING/WARMING AS RIDGE REBUILDS BEHIND
DEPARTING TROUGH. BEYOND 7 DAYS...IF MRF IS CORRECT...THIS
WARMING/OFFSHORE TREND WILL BE SHORTLIVED AS MAIN RIDGE RETROGRADES
EVEN FURTHER WEST...TO AROUND 160 W LONGITUDE...ALLOWING LONG WAVE
TROUGH TO SET UP RESIDENCE ALONG 125 W LONGITUDE.
.SAN...NONE.
BALFOUR
AREA FORECAST DISCUSSION
NWS GRAY ME
AFDGYX 910 AM EST SAT JAN 12 2002
WL BE UPDATING TO CLEAN UP WORDING FOR THE MTNS...AND INCR THE AMT
OF CLDS FOR PTNS OF SRN NH...ESP ALG THE CT RIVER.
VIS LOOP SHOWS THE SC ACRS CNTRL AND SRN NH IS STARTING TO SHOW SUM
TENDENCY TO TRY TO BREAK. ACARS SOUNDINGS FM MHT THIS MRNG SHOW IN
THE INVERSION HERE TO BE BETWEEN 6.0 AND 6.5 KFT...AND THIS MAY BE
ENUF TO ALLOW BREAKS TO BECOME MORE PREVALENT WITH TIME. WL
PROBABLY START THE UPDATED ZNS WITH A MENTION OF MORE CLDS...THEN
ALLOW BREAKS AS MIXING OCCURS.
THE ONLY EXCEPTION HERE MAY BE NHZ005-007...SINCE THE UPSLOPE
COMPONENT OF THE FLOW MAY ALLOW CLDS TO HANG IN LONGER. IN
ADDITION...MORE IN THE WAY OF CLDS INADVOF A MID LEVEL WMFNT MAY
KEEP THINGS CLOUDER.
ACRS THE MTNS...THE AMT OF DEEP MOIST IS DROPPING...BUT GYX-88D IS
SHOWING SIGNS OF THE UPSLOPE CONTINUING. WL WATCH TRENDS FOR THE
NEXT HOUR OR SO...AND MAY HAVE TO KEEP FLURRIES FOR PTNS OF THE
UPSLOPE AREA. REGARDLESS...APPEARS AS THO THE MTNS AND FOOTHILLS
MAY CLEAR ENUF FOR P/SUNNY TO WORK.
ELSEWHERE...WL CONT WITH P/SUNNY AS THE DOWNSLOPE SHUD FIGHT OFF THE
LOW TO MID LEVEL MOIST AHEAD OF THE APCHG WMFNT.
FOR NOW...MAXES APPEAR OK...AND WL CHECK 1000 AM OBS FOR TRENDS AND
ADJUST AS NECESSARY.
AS FOR WINDS...THE BEST MIXING IS OCCURRING NOW...AND WUD EXPECT
WINDS TO CONTINUE TO TREND DOWNWARD AS FCST.
NO OTHER CHANGES TO THE PUBLIC FCST. OBVIOUSLY...SUM DIFFERENCES IN
THE DETAILS AMONG MODELS FOR SUN EVENT. FOR NOW...WL LET THE
CURRENT FCST RIDE (NO HEADLINES WITH THE UPDATE) AND REEVALUATE WITH
THE AFTN PACKAGE.
ON THE COASTAL WATERS...THE BEST MIXING IS OCCURRING NOW AND WL BE
FINISHED SOON. ONLY BUOY CLOSE TO GLW IS MDRM1. WITH THIS IN
MIND...WL DROP BACK TO SCA FOR THE 1ST PART OF THIS AFTN...AND DROP
WINDS BLO THIS FOR THE 2ND HALF OF THE AFTN. IN ADDITION...WITH THR
DROPPING OF THE GLW...WL ADD THE HEADLINE OF GLW MAY BE NEEDED FOR
SUN AFTN.
WRKCWF/WRKZFP AVBL SOON. EXPECT TO HAVE THE UPDATED ZNS OUT AFTER
1000 AM. COMMENTS/OPINIONS WELCOME.
.GYX...SCA.
HAYES