Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 270402
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
900 PM PDT TUE MAY 26 2015

.SYNOPSIS...
A DEEP MARINE LAYER TONIGHT AND WEDNESDAY WILL CONTINUE WIDESPREAD
LOW CLOUDS WITH PATCHY DRIZZLE WEST OF THE MOUNTAINS...WITH SLOW
CLEARING WEDNESDAY. THE MARINE LAYER WILL GRADUALLY BECOME MORE
SHALLOW WEDNESDAY NIGHT THROUGH THE WEEKEND AS HIGH PRESSURE ALOFT
DEVELOPS...RESULTING IN WARMER WEATHER INLAND AND BETTER AFTERNOON
CLEARING...EXCEPT AT THE IMMEDIATE COAST WHERE COOL MOSTLY CLOUDY
WEATHER WILL CONTINUE. SLIGHT COOLING WILL OCCUR EARLY NEXT WEEK AS
ANOTHER TROUGH OF LOW PRESSURE MOVES THROUGH THE WEST COAST.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

STRATUS WAS SPREADING RAPIDLY INLAND AND WAS ALREADY REACHING THE
COASTAL SLOPES OF SAN DIEGO COUNTY AT MID-EVENING AS WELL AS
COVERING MOST OF ORANGE COUNTY. AN UPPER LOW WAS WELL REPRESENTED IN
THE WATER VAPOR AND IR IMAGES ABOUT 250 MILES WEST OF SAN
DIEGO...MOVING EAST. THAT UPPER LOW HAS SOME MID/HIGH CLOUDS...BUT
OTHERWISE THE ONLY REAL MOISTURE FOR IT TO WORK WITH IS THE MARINE
LAYER...WHICH IS CONTRIBUTING MOSTLY TO THE 0.64" OF PRECIPITABLE
WATER. THE UPPER LOW IS NOT CONNECTED TO THE SURFACE FLOW...EITHER
IN THE WIND OR OMEGA FIELDS...SO IT WILL NOT REALLY CONTRIBUTE TO
PRECIPITATION. HOWEVER...EXPECT PATCHY DRIZZLE TO FORM YET AGAIN
LATE TONIGHT/EARLY WEDNESDAY...AND A FEW LOCATIONS COULD HAVE A FEW
HUNDREDTHS OF AN INCH OF ACCUMULATION OF PRECIP DUE TO WHAT WILL
AGAIN BE A RATHER THICK CLOUD LAYER...1000-1500 FEET DEEP...AND
CONTINUED ONSHORE FLOW. THAT THICK CLOUD LAYER WILL BE RATHER SLOW
TO CLEAR...BUT LOCAL WRF INDICATES DECENT CLEARING IN THE AFTERNOON
AWAY FROM THE COAST.

AFTER THE LOW MOVES EAST OF SOUTHERN CALIFORNIA LATE WEDNESDAY...A
RIDGE WILL BE ABLE TO BUILD IN...THOUGH MUCH WEAKER THAN THE STRONG
ONES THAT WE EXPERIENCED EARLIER THIS YEAR. THE MAIN EFFECTS OF THE
RIDGE WILL BE BRING TEMPERATURES TO NEAR TO A LITTLE ABOVE NORMAL
(UP TO 5 DEG F) TO INLAND AREAS STARTING THURSDAY AND MAKE THE
MARINE LAYER MORE SHALLOW. THIS MEANS LESS OF THE VALLEY STRATUS AT
NIGHT...AND BETTER CLEARING. WITH THE ONSHORE FLOW CONTINUING...THE
TIME OF YEAR...AND A STRONGER INVERSION...THERE WILL LIKELY BE AREAS
WITHIN A FEW MILES OF THE COAST THAT ONLY HAVE PARTIAL AFTERNOON
CLEARING ON SOME OF THE DAYS THROUGH THE WEEKEND. DESPITE THE MARINE
LAYER...TEMPS WILL BE NEAR NORMAL AT THE COAST BY THE
WEEKEND...THOUGH THAT IS NOT SAYING MUCH AS THE AVERAGE HIGH IS
STILL ONLY 70 AT LINDBERGH FIELD DUE TO THE MARINE LAYER NORMALLY
PREVAILING AT THIS TIME OF YEAR.

EARLY NEXT WEEK...THERE WILL BE A TROUGH MOVING EAST FROM THE NE
PACIFIC TO THE WEST COAST. MOST OF THE EFFECTS WILL BE NORTH OF
SOUTHERN CALIFORNIA...BUT DOWN HERE THERE SHOULD BE A SLIGHT
DECREASE IN TEMPERATURES.

&&

.AVIATION...
270330Z...COAST/VALLEYS...HIGH CONFIDENCE THAT OVC-BKN SKIES
WILL PREVAIL THROUGH 18Z...WITH BASES AROUND 1200-2200 FT MSL AND
TOPS OF 2500-3000 FT MSL. LOWEST BASES WILL OCCUR BETWEEN 10Z AND
16Z. VIS RESTRICTIONS OF 4SM OR LESS ARE PROBABLE OVER PORTIONS
OF THE INLAND EMPIRE AND ALONG THE COASTAL FOOTHILLS. AFTER 18Z
WEDNESDAY...CONFIDENCE IN CIGS IS LOWER...THOUGH SCT-BKN LOW CLOUDS
WITH SUB 2000 FT MSL BASES WILL LIKELY LINGER ALONG THE COAST INTO
THE AFTERNOON. LOW CLOUDS WILL REBUILD ALONG THE COAST WEDNESDAY
EVENING WITH BASE BETWEEN 1000 AND 1500 FT MSL.


MTNS/DESERTS...UNRESTRICTED VIS AND BKN-SCT CLOUDS AOA 20000 FT MSL.

&&

.MARINE...
830 PM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH SUNDAY
EVENING.

&&

.SKYWARN...
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...MAXWELL
AVIATION/MARINE...ALBRIGHT



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