EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION...
NWS SAN DIEGO CA
AFDSAN 230 PM PDT SAT APR 22 2000
...SYNOPSIS...
A DEEP MARINE LAYER AND A WEAK COASTAL EDDY WILL BRING EXTENSIVE
CLOUDS WEST OF THE MOUNTAINS TONIGHT AND TOMORROW...WITH GRADUAL
CLEARING SUNDAY AFTERNOON. BUILDING HIGH PRESSURE OVER THE WEST WILL
THEN START A WARMING TREND THAT WILL LAST THROUGH THROUGH THE MIDDLE
OF NEXT WEEK.
...DISCUSSION...
DUE TO EQUIPMENT PROBLEMS THE 00Z NKX SOUNDING WILL NOT BE AVAILABLE
THIS EVENING. HOPE TO HAVE EFFECTED REPAIRS FOR THE 12Z SUNDAY
MORNING FLIGHT.
ACARS DATA STILL SHOWING A VERY DEEP MARINE LAYER NEAR 6000 FEET. AS
A RESULT...SKIES CLEARED IN FEW SPOTS (THE ORANGE COUNTY
BEACHES,)...BUT MANY AREAS REMAINED EITHER BROKEN OR OVERCAST. THIS
DEEP MOIST LAYER COMBINED WITH A WEAK EDDY OFF THE COAST OF SAN
DIEGO WILL BRING CLOUDS BACK TO ALL AREAS WEST OF THE MTNS TONIGHT.
WEAK SHORTWAVES MOVE THROUGH A FLAT RIDGE OVER SOCAL THE NEXT 2
DAYS. NEVERTHELESS...HEIGHTS RISE SLOWLY THROUGH THE PERIOD BUT
THERE WILL STILL BE A FAIRLY DEEP MARINE LAYER TOMORROW WHICH WILL
KEEP TEMPERATURES IN CHECK WEST OF THE MOUNTAINS...ONLY IN THE 60S
AND LOW 70S. EXPECT BETTER CLEARING IN THE AFTERNOON...ESPECIALLY IN
THE INLAND EMPIRE AND ORANGE COUNTY...AS FLOW ALOFT BECOMES MORE
NORTHERLY.
A WARMING TREND IS SETTING UP FOR NEXT WEEK AS A RIDGE BEGINS TO
BUILD AHEAD OF DEVELOPING LOW PRESSURE IN THE CENTRAL PACIFIC. THIS
RIDGE WILL BE OUR MAIN WEATHER MAKER FOR MIDWEEK WITH SUNNY AND
WARMER DAYS AND ABOVE AVERAGE TEMPERATURES.
SAN 000
.SAN...NONE.
MOEDE
EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION...
NWS SAN DIEGO CA
AFDSAN 930 AM PDT SAT APR 22 2000
...SYNOPSIS...
A DEEP MARINE LAYER WILL KEEP CLOUDS LINGERING THROUGH THE AFTERNOON
IN THE COASTAL AND INLAND SECTIONS TODAY. STRONG ONSHORE FLOW WILL
BRING GUSTY WINDS TO THE MOUNTAINS AND DESERTS. DRY WITH A WARMING
TREND EARLY NEXT WEEK AS HIGH PRESSURE BUILDS OVER SOUTHERN
CALIFORNIA.
...DISCUSSION...
12Z NKX SOUNDING UNAVAILABLE THIS MORNING DUE TO EQUIPMENT
PROBLEMS...BUT ACARS DATA SHOWED A VERY DEEP MARINE LAYER NEAR 7000
FEET DEEP. POCKETS OF DRIZZLE AND LIGHT RAIN WERE REPORTED THIS
MORNING WEST OF THE MOUNTAINS.
OVER THE NEXT 48 HOURS THE SYNOPTIC PATTERN GRADUALLY BECOMES
ANTICYCLONIC AS UPPER LOW OVER AZ MOVES EAST AND IS REPLACED BY A
WEAK RIDGE. THIS WILL SHRINK THE DEPTH OF THE MARINE LAYER BUT IT
WILL BE A VERY SLOW PROCESS...AND EXPECT LIMITED CLEARING THIS
AFTERNOON. STRONG ONSHORE PRESSURE GRADIENTS WILL BRING GUSTY
NORTHWEST WINDS TO THE MTNS AND DESERTS.
LOW CLOUDS WILL RETURN TO ALL AREAS WEST OF THE MOUNTAINS
TONIGHT. BETTER CLEARING SUNDAY AFTERNOON DUE TO A SHALLOWER MARINE
LAYER AND WEAKER ONSHORE FLOW. HIGHER 500 MB HTS AND WARMER 850 MB
TEMPS WILL RESULT IN SEVERAL DEGREES OF WARMING TOMORROW.
EXTENDED...WEAK RIDGE FORECAST OVER THE WEST COAST THROUGH MID WEEK
FOR GRADUAL WARMING EACH DAY THROUGH WEDNESDAY.
UPDATE WILL BY ISSUED TO ADD AFTERNOON CLOUDS TO THE FORECAST.
SAN 000
.SAN...NONE.
MOEDE
AREA FORECAST DISCUSSION
NWS SEATTLE WA
AFDSEW 335 PM PDT SAT APR 22 2000
SATELLITE IMAGERY SHOWS PLENTY OF CU OVER WESTERN WASHINGTON LATE
THIS AFTERNOON. A COUPLE OF SPOTTER REPORTS FROM THE SOUTH SOUND HAD
ICE PELLETS MIXED IN WITH THE SHOWERS. ACARS SOUNDINGS SHOW 500 MB
TEMPS -26C OVER WESTERN WASHINGTON. SATELLITE IMAGERY SHOWS CLEARING
OFF THE COAST AND SHOWER ACTIVITY SHOULD SETTLE DOWN ONCE SUN GOES
DOWN. NEXT VORT MAX CURRENTLY NEAR 50N/138W MOVING INTO BRITISH
COLUMBIA SUNDAY. WESTERN WASHINGTON ON THE EXTREME SOUTHERN END OF
THIS WITH 500 MB TEMPS FALLING TO NEAR -30C. MODELS SOUNDING UNSTABLE
MOST OF THE DAY TOMORROW WITH LI'S NEAR ZERO ON ALL THE MODELS. HAVE
PUT CHANCE OF THUNDERSTORMS IN THE FORECAST FOR TOMORROW AND WILL
INCLUDE ICE PELLETS GIVEN REPORTS THIS AFTERNOON AND CONDITIONS EVEN
MORE FAVORABLE SUN AFTERNOON. ONCE THIS NEXT BATCH OF COLD AIR MOVES
THROUGH IMPROVING TREND BEGINNING SUN NIGHT. SURFACE HI PRES BUILDING
IN OVER THE AREA SUN NIGHT AND WEAK UPPER LEVEL RIDGE OUT AHEAD OF
THE NEXT SYSTEM MOVING OVER WESTERN WASHINGTON ON MONDAY GIVING A
BREAK IN THE WET WEATHER.
.EXTENDED...EXTENDED MODELS HAVE DIFFERENT SOLUTIONS FOR THE EXTENDED
PERIOD. MRF IS THE FASTEST MODEL WITH THE NEXT SYSTEM ON TUE WHILE
THE EURO IS THE SLOWEST. MRF HINTING AT A RETURN TO THE SPLIT WITH
THE SYSTEM ON THURSDAY DIGGING OFF THE WEST COAST. LOW CONFIDENCE IN
THE MODELS RIGHT NOW SO WILL BROAD BRUSH EXTENDED SOMEWHAT. FELTON
UIL 3831 SEA 3731 OLM 3831
.KATX...VCP21/CSR21...OPERATIONAL
.SEW...NONE
N