Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 282051
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
151 PM PDT MON JUL 28 2014

.SYNOPSIS...
THE INCREASED POSSIBILITY OF THUNDERSTORMS CONTINUES TODAY AS
SUFFICIENT MONSOONAL MOISTURE REMAINS IN PLACE. DRIER AIR MOVING
INTO THE REGION WILL LIMIT THUNDERSTORM CHANCES TO THE MOUNTAINS
ON TUESDAY AND WEDNESDAY...THEN DIMINISH CHANCES FOR THE REMAINDER
OF THE WEEK. NEAR NORMAL TEMPERATURES WILL CONTINUE THROUGH MID-
WEEK...THEN INCREASE TO SLIGHTLY ABOVE NORMAL THROUGH THE WEEKEND.
HIGH PRESSURE ALOFT WILL CONTINUE A PATCHY...SHALLOW MARINE LAYER.

&&

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

AT 1 PM PDT...WATER VAPOR SATELLITE IMAGERY DISPLAYED AN UPPER-
LEVEL RIDGE CENTERED OVER THE MEXICO/TEXAS/NEW MEXICO
BORDER...AND A WEAK DISTURBANCE OVER SOUTHERN CA. COMPOSITE RADAR
IMAGERY SHOWED ISOLATED THUNDERSTORMS DEVELOPING IN THE
MOUNTAINS...MAINLY NEAR THE HIGHEST PEAKS.

THE POSSIBILITY OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
WILL CONTINUE THIS AFTERNOON...MAINLY OVER THE FAR INLAND
VALLEYS...MOUNTAINS AND DESERTS. ALTHOUGH THERE IS PLENTY OF
MONSOONAL MOISTURE ACROSS THE AREA...WIDESPREAD STORM ACTIVITY IS
NOT EXPECTED AT THIS TIME FROM SUBSIDENCE TRAILING BEHIND THE
DISTURBANCE ALOFT. STORMS THAT DO DEVELOP COULD GENERATE HEAVY
RAIN...LOCALIZED FLASH FLOODING...GUSTY WINDS AND CLOUD-TO-GROUND
LIGHTNING.

THE AFOREMENTIONED UPPER-LEVEL HIGH PRESSURE WILL SHIFT SOUTH
TUESDAY...SHIFTING THE UPPER-LEVEL FLOW FROM SE TO SW. THIS WILL
HELP TRANSPORT SOME MID AND UPPER-LEVEL MOISTURE TO THE AREA FROM
TROPICAL STORM HERNAN. CLOUDS AND VIRGA ARE EXPECTED FROM THE SW
FLOW. HOWEVER...ISOLATED THUNDERSTORMS WILL BE POSSIBLE TUESDAY
AND WEDNESDAY AFTERNOON...MAINLY OVER MOUNTAIN PEAKS.

THE HIGH WILL THEN BUILD WEST OVER SW CA THURSDAY THROUGH THE
END OF THE WEEK...WHICH WILL HELP TO DRY OUT THE
ATMOSPHERE...REMOVE THE POSSIBILITY OF THUNDERSTORMS AND SLIGHTLY
INCREASE HIGH TEMPERATURES TO A FEW DEGREES ABOVE NORMAL THROUGH
FRIDAY. 28/1200 UTC ECMWF/GFS/GEM MODEL RUNS HINT AT PRECIP
RETURNING TO THE MOUNTAINS AND DESERTS POSSIBLY BY THE END OF NEXT
WEEKEND. SINCE THEY HAVE BEEN INCONSISTENT FOR THE PAST FEW RUNS
AND DISAGREE ON TIMING...HAVE LEFT STORMS OUT OF THE FORECAST FOR
NOW. THE MARINE LAYER WILL REMAIN FAIRLY SHALLOW AND PATCHY...WITH
LOW CLOUDS AND FOG RESTRICTED MAINLY TO THE COAST AND COASTAL
VALLEYS.

&&

.AVIATION...
282000Z...COASTS/VALLEYS...A PATCHY LOW CLOUD DECK WITH BASES
NEAR 1000 FT MSL AND TOPS 1300 FT MSL SHOULD DEVELOP OVER THE
COASTAL WATERS TONIGHT AND MOVE UP TO 5 SM INLAND BETWEEN 28
/0900Z-1300Z... AFFECTING KSAN...KCRQ...AND KSNA. CONFIDENCE OF A
BKN/OVC LAYER OCCURRING AT THESE AIRPORTS IS LOW TO MODERATE. SKC
CONDS EXPECTED DURING THE DAY TUESDAY.

MOUNTAINS/DESERTS...SCATTERED MOUNTAIN TSTORMS AND ISOLATED DESERT
TSTORMS WILL CONTINUE TO DEVELOP THROUGH 29/0200Z WITH BASES
6000-8000 FT MSL AND TOPS TO 35000 FT MSL. SHOWERS AND THUNDERSTORMS
DIMINISHING THIS EVENING. OTHERWISE MULTIPLE SCT-BKN CLOUD LAYERS AT
OR ABOVE 8000 FT MSL.

&&

.MARINE...
115 PM PDT...NO HAZARDOUS MARINE WEATHER EXPECTED TONIGHT THROUGH
FRIDAY.

&&

.SKWYARN...
SKYWARN ACTIVATION IS REQUESTED FOR SAN BERNARDINO AND SAN DIEGO
COUNTIES.

&&

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

&&

$$

PUBLIC...JJT
AVIATION/MARINE...JT







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