000
FXUS66 KSGX 122050
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
150 PM PDT SUN MAY 12 2013

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER CALIFORNIA THROUGH MONDAY...WITH VERY
HOT CONDITIONS PREVAILING ACROSS THE INLAND AREAS.  A FEW RECORDS
WILL LIKELY FALL AGAIN TOMORROW.  HOWEVER...A VERY SHALLOW MARINE
WILL LINGER ALONG THE COAST...MODERATING TEMPERATURES AND BRINGING
AREAS OF DENSE FOG POSSIBLE EACH NIGHT.  A GRADUAL COOLING TREND
WILL DEVELOP BY MIDWEEK...AS THE MARINE LAYER DEEPENS AND THE RIDGE
FLATTENS.  A TROUGH WILL THEN DEVELOP ALONG THE WEST COAST AND MOVE
INLAND FOR THE REMAINDER OF THE WEEK AND WEEKEND...BRINGING MUCH
COOLER CONDITIONS...A DEEPER MARINE LAYER...AND GUSTY WEST WINDS IN
THE MOUNTAINS AND DESERTS.

&&

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

WATER VAPOR IMAGERY CONTINUES TO SHOW A STRONG RIDGE OF HIGH
PRESSURE OVER CALIFORNIA THIS AFTERNOON...AS A TROUGH OF LOW
PRESSURE APPROACHES THE PACIFIC NORTHWEST.  AS A RESULT...INLAND
AREAS SAW SIGNIFICANTLY HEAT UP TODAY...WHICH CORRESPONDED WELL TO
THE WARMING SEEN ON THE 12Z KNKX SOUNDING THIS MORNING.  A NUMBER OF
LOCATIONS IN THE INLAND EMPIRE HIT THE CENTURY MARK...AND A FEW
LOCATIONS LIKELY BROKE RECORDS TODAY.  INLAND TEMPERATURES AT 1 PM
ARE RUNNING 4 TO 9 DEGREES WARMER THAN THIS TIME YESTERDAY...WHILE
COASTAL AREAS ARE SIMILAR TO OR EVEN A FEW DEGREES COOLER.  THIS IS
IN PART TO THE VERY PERSIST AND SHALLOW MARINE LAYER BLANKETING THE
BEACHES THIS AFTERNOON.  IN FACT...A NUMBER OF THE LIFEGUARD REPORTS
ARE ALREADY SHOWING REDUCED VISIBILITIES IN FOG.  FOR THIS
REASON...HAVE ALREADY ISSUED A DENSE FOG FOR TONIGHT FOR THE COASTAL
AREAS...AS THIS FOG WILL LIKELY BE DENSE AND WIDESPREAD WITHIN 10
MILES OF THE COASTLINE.  OTHERWISE...EXPECT INLAND AREAS REMAINING
VERY WARM EVENING...WITH OVERNIGHT TEMPERATURES REMAINING QUITE
MILD.

OTHERWISE...EXPECT THIS HOT CONDITIONS TO CONTINUE TO PREVAIL ACROSS
THE REGION ON MONDAY...AS THE RIDGE AXIS PLANTS ITSELF OVER SOUTHERN
CALIFORNIA.  850 MB TEMPERATURES ON MONDAY WILL INCREASE TO BETWEEN
23 AND 26 DEGREES OVER SOUTHERN CALIFORNIA...WITH TEMPERATURES
SIMILAR TO OR EVEN A FEW DEGREES WARMER.  THIS WILL LIKELY BE THE
HOTTEST DAY OF THE WEEK...WITH MORE RECORD BREAKING TEMPERATURES
POSSIBLE.

A GRADUAL COOLING TREND WILL THEN DEVELOP FOR TUESDAY AND
WEDNESDAY...AS THE RIDGE WEAKENS AND FLATTENS A BIT.  THE LOCAL WRF
IS ALSO SHOWING AN EDDY DEVELOPING TUESDAY NIGHT...SO EXPECT A
GRADUAL DEEPENING OF THE MARINE LAYER THESE DAYS.  HOWEVER...A MORE
SIGNIFICANT COOLING TREND WILL THEN DEVELOP OVER THE SOUTHLAND FOR
THE REMAINDER OF THE WORK WEEK AND AT LEAST THE FIRST PART OF THE
WEEKEND...AS A TROUGH DEEPENS ALONG THE WEST COAST AND MOVES
INLAND.  THEREFORE...EXPECT THE COOLER CONDITIONS TO CONTINUE TO
PREVAIL...ALONG WITH A DEEPER MARINE LAYER POTENTIALLY PUSHING WELL
INTO THE INLAND VALLEYS.  LOCALLY GUSTY WEST WINDS WILL ALSO DEVELOP
IN THE MOUNTAINS AND DESERTS THESE DAYS.

&&

.AVIATION...
122025Z...COAST/VALLEYS... CLEAR SKIES AND UNRESTRICTED VISIBILITIES
OVER LAND AREAS...EXCEPT AT THE IMMEDIATE COASTLINE LOCAL LOW CLOUDS
BASED AROUND 300 FEET MSL WITH TOPS AROUND 800...ALONG WITH
LOCALIZED VISIBILITIES BELOW 3 MILES IN FOG THROUGH 13/0100Z. LATER
THIS AFTERNOON THROUGH MONDAY MORNING...FROM 13/0100Z TO
13/1400Z...THE VERY LOW STATUS/DENSE FOG WILL PUSH INLAND...REACHING
AROUND 10SM INLAND BY 13/1200Z. STRATUS/FOG WILL CLEAR TO THE
COASTAL WATERS...AND RESULT IN CLEAR SKIES AND UNRESTRICTED
VISIBILITIES OVER LAND AREAS AGAIN AFTER ABOUT 13/1700Z MONDAY
MORNING.

MTNS/DESERTS...UNRESTRICTED VIS WITH FEW CLDS AOA 10000 FT MSL IN
THE MTNS AND SKC ELSEWHERE THROUGH MONDAY MORNING.

&&

.FIRE WEATHER...
VERY HOT AND DRY CONDITIONS WILL PREVAIL ACROSS THE INLAND AREAS
AGAIN ON MONDAY...WITH DAYTIME HUMIDITY VALUES FALLING BELOW 15
PERCENT AFTER WIDESPREAD POOR TO MODERATE RECOVERIES TONIGHT.
HOWEVER...THE WINDS WILL REMAIN RELATIVELY LIGHT AND TERRAIN
DRIVEN...WITH WEAK ONSHORE WINDS DURING THE AFTERNOON DEVELOPING.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...DENSE FOG ADVISORY FROM 6 PM THIS EVENING TO 9 AM PDT MONDAY FOR
     THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO COUNTY COASTAL
     AREAS.

PZ...NONE.

&&

$$

PUBLIC/FIRE...PALMER
AVIATION/MARINE...SMALL