EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
AFDSAN 200 PM PDT SUN JUN 13 1999
...SYNOPSIS...
HIGH PRESSURE WILL BRING FAIR WEATHER THROUGH TUESDAY. A WEAK
ONSHORE FLOW AND A SHALLOW MARINE LAYER WILL CONFINE THE NIGHT AND
MORNING LOW CLOUDS AND PATCHY DENSE FOG TO THE IMMEDIATE COAST.
...DISCUSSION...
THE MARINE LAYER CONTINUES TO SHRINK IN RESPONSE TO A COMBINATION OF
INCREASED SUBSIDENCE AS WELL AS AN EASTERLY FLOW ALOFT. ST/FOG IS
CURRENTLY CONFINED TO THE SAN DIEGO COUNTY IMMEDIATE COAST AND THIS
AREA CONTINUES TO SHRINK. THE NEXT AREA OF ST/FOG IS ABOUT 60 TO 70
NM OFFSHORE.
OVER THE LAND AREAS THE SKY IS CLEAR. TEMPERATURES ARE MOSTLY 3 TO 5
DEGREES HIGHER THAN THE SAME TIME ON SATURDAY NEAR THE COAST AND
BETWEEN 6 TO 12 DEGREES HIGHER OVER THE INLAND AREAS INCLUDING THE
DESERTS. THE ONLY EXCEPTION IS ALONG THE SAN DIEGO COAST WHERE THE
ST/FOG HAS BEEN HUGGING THE COASTLINE TEMPERATURES ARE ABOUT A
DEGREE OR TWO LOWER.
BOTH THE KSOX AND KNKX 88D VWPS SHOW AN EASTERLY FLOW ALOFT ABOVE
5000 FEET ACROSS THE AREA. THIS IS ALSO SHOWING UP ON RECENT ACARS
SOUNDINGS OUT OF PSP AND LAX.
12Z MODELS ARE IN GENERAL AGREEMENT WITH THE RIDGE PEAKING TODAY AND
MONDAY THEN DECREASING SLIGHTLY BY TUESDAY AS A S/WV TROUGH SWINGS
NORTHEAST FROM THE DEEP GULF OF ALASKA LOW INTO THE PACIFIC
NORTHWEST AND WESTERN CANADA. AS THIS S/WV BRUSHES BY...A PORTION OF
THE RIDGE BREAKS OFF AND DEVELOPS INTO A HIGH NEAR FOUR CORNERS ON
TUESDAY AS THE MAIN RIDGE REMAINS TO THE SOUTHWEST OF THE COAST. A
NORTHWEST FLOW ALOFT SETS UP OVER SOUTHERN CALIFORNIA. THIS WILL
PREVENT ANY SUBTROPICAL MOISTURE FROM REACHING THE AREA FROM MEXICO
AT LEAST THROUGH WEDNESDAY. ANY MOISTURE WILL REMAIN WELL TO THE
EAST OF SOUTHERN CALIFORNIA. A SLIGHT DECREASE IN THICKNESS WILL
BRING A DEGREE OR TWO COOLING ON TUESDAY TO THE INLAND AREAS. MORE
SIGNIFICANT COOLING IS EXPECTED ALONG THE COAST AS THE MARINE LAYER
REESTABLISHES ITSELF.
MAIN PROBLEM FOR OUR CWFA WILL BE THE ST/FOG ALONG THE SAN DIEGO
COAST. STRONG GUSTY WIND NORTHWEST WIND CONTINUES NEAR POINT
CONCEPTION WHICH COULD SPIN UP AN EDDY. THIS COULD OFFSET THE
LOWERING OF THE MARINE LAYER CAUSED BY THE RIDGING ALOFT. AS A
RESULT...ST/FOG SHOULD RETURN TO THE COAST OF SAN DIEGO COUNTY
TONIGHT. FOG COULD BE LOCALLY DENSE NEAR THE BEACHES. HOWEVER...DO
NOT EXPECT MUCH INLAND PENETRATION OF THE ST/FOG TONIGHT. WILL GO
WITH AREAS FOR THE SAN DIEGO COAST AND JUST PATCHY FOR ORANGE COUNTY.
MEDIUM RANGE MODELS KEEP US UNDER A TYPICAL EARLY SUMMER PATTERN
WITH A HIGH NEAR FOUR CORNERS AND A TROUGH OVER THE EASTERN PACIFIC
WITH A SOUTHWEST FLOW OVER SOUTHERN CALIFORNIA. EXPECT WARM DRY
WEATHER TO CONTINUE.
ASTRONOMICAL HIGH TIDES 7.0 FEET OR HIGHER ARE FORECAST THROUGH
TUESDAY ALONG THE SAN DIEGO COAST SO A MWS FOR POSSIBLE MINOR TIDAL
OVERFLOW REMAINS IN EFFECT.
SAN 0000
.SAN...MINOR TIDAL OVERFLOW THREAT ORANGE AND SAN DIEGO COUNTY COASTS
SEE LAXMWSSAN
HORTON
AREA FORECAST DISCUSSION
NWS SEATTLE WA
AFDSEW 900 PM PDT SUN JUN 13 1999
SATELLITE IMAGERY SHOWS CLOUDS TOPS ASSOCIATED WITH FRONT NR 137W
WARMING AS FRONT MOVES INTO UPPER LEVEL RIDGE ALONG PAC NW COAST.
LAST LOOK AT VISIBLE PICTURES HAD STRATUS OFFSHORE BUT MOVING
PARALLEL TO THE COAST. FRONT BECOMING MORE NORTH-SOUTH ORIENTED AS
COLD AIR BEHIND THE FRONT CONTINUES TO DIG. ACARS SOUNDINGS IN AND
OUT OF KSEA HAVE 850 MB TEMPS +13 OR 14C RIGHT NOW. AS UPPER LEVEL
RIDGE BUILDS A LITTLE MORE OVERNIGHT MODEL PROJECTIONS OF 850 MB
TEMPS OF +16 TO 18C TOMORROW AFTERNOON LOOK GOOD. NORTHERLY AFTERNOON
SURFACE GRADIENTS WILL CUT MAX TEMPS DOWN SO WILL CALL IT A WASH AND
STAY WITH SIMILAR MAXS AS TODAY. QUESTION IS ON TUESDAY. FLOW ALOFT
STAYS SOUTHERLY WITH HEIGHTS SLOWLY FALLING AND UPPER LEVEL RIDGE
AXIS OVER IDAHO. FIRST LOOK AT ETA AND NGM HAVE ONSHORE GRADIENTS
DEVELOPING TUE MORNING WITH A STRONGER PUSH THEN PREVIOUS RUNS AS
WEAK SURFACE RIDGING AHEAD OF FRONT THAT IS DISSIPATING OFFSHORE
REACHES THE COAST. QUESTION IS HOW STRONG WILL THIS SURFACE RIDGE BE.
WILL WAIT FOR AVN TO COME IN. IN THE MEANTIME NO CHANGES TO THE
CURRENT PACKAGE. FELTON
SEA 0000 OLM 0000 UIL 0022
.KATX...VCP32/CSR32...OPERATIONAL.
.SEW...SCA COAST FOR ROUGH BAR.