Flash Flood Watch 5, NWS San Diego, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 AM PDT TUE AUG 12 2014

.SYNOPSIS...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
OVER THE MOUNTAINS AND DESERTS THROUGH THIS EVENING.  HOWEVER...AN
UPPER LEVEL TROUGH OF LOW PRESSURE WILL MOVE INLAND OVER CALIFORNIA
TONIGHT AND WEDNESDAY...BRINGING DRIER AND SLIGHTLY COOLER
CONDITIONS TO THE REGION.  SOUTHWESTERLY FLOW ALOFT WILL PREVAIL
ACROSS THE REGION THROUGH EARLY NEXT WEEK...WITH DRY CONDITIONS
PREVAILING.  TEMPERATURES WILL REMAIN NEAR OR SLIGHTLY BELOW NORMAL
MOST AREAS DURING THE WEEK...WITH COASTAL LOW CLOUDS AND FOG
POSSIBLE ALONG THE COAST EACH NIGHT.

&&

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

WATER VAPOR IMAGERY SHOWS A TROUGH OF LOW PRESSURE DIGGING ALONG THE
WEST COAST THIS MORNING...WITH AN IMPRESSIVE NEGATIVELY TILTED
DISTURBANCE LIFTING ACROSS NORTHERN CALIFORNIA AND NEVADA AT THIS
TIME.  MEANWHILE...THE REMNANTS OF AN MCS AND OUTFLOW BOUNDARY MOVED
ACROSS SOUTHEASTERN CALIFORNIA THIS MORNING...WHICH BROUGHT SOME
SCATTERED SHOWERS AND THUNDERSTORMS TO OUR SOUTHERN MOUNTAINS AND
DESERTS.  A COUPLE OF LOCATIONS IN THE SAN DIEGO COUNTY MOUNTAINS
PICKED UP A FEW HUNDREDTHS...WHILE DESERT LOCATIONS ONLY REPORTED
TRACE AMOUNTS.  ALTHOUGH THINGS ARE NOW RELATIVELY QUIET...EXPECT
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TO REDEVELOP OVER
THE MOUNTAINS AND DESERTS AGAIN THIS AFTERNOON.  THE 12Z KNKX
SOUNDING SHOWS PW VALUES OF 1.52 INCHES...WHICH MEANS FLASH FLOODING
COULD BE POSSIBLE.  HOWEVER...THE UPPER LEVEL WINDS ARE RANGING
BETWEEN 15 AND 25 KT...SO ANY STORMS THAT FORM WILL LIKELY ONLY
PRODUCE BRIEF SHOWERS OF ANY GIVEN AREA.

AS THIS TROUGH OF LOW PRESSURE ALONG THE WEST COAST MOVES INLAND
TONIGHT AND ON WEDNESDAY...DRIER CONDITIONS WILL DEVELOP ACROSS
SOUTHERN CALIFORNIA.  A MINOR COOLING TREND WILL ALSO DEVELOP...WITH
THE MARINE LAYER WILL DEEPENING EVER SO SLIGHTLY AS WELL FOR
WEDNESDAY.  THE MODELS THEN SHOW SOUTHWESTERLY FLOW ALOFT PREVAILING
ACROSS SOUTHERN CALIFORNIA THROUGH EARLY NEXT WEEK...AS ANOTHER
TROUGH DEVELOPS ALONG THE COAST.  THE HEIGHT OVER SOUTHERN
CALIFORNIA MAY VERY A BIT FROM DAY TO DAY...BUT EXPECT TEMPERATURES
TO REMAIN NEAR OR SLIGHTLY BELOW SEASONAL NORMS FOR THE
PERIOD...WITH DRY CONDITIONS PREVAILING.

&&

.AVIATION...
121530Z...LOW CLOUDS ARE CLEARING ALONG THE COASTS TO INLAND VALLEYS
ABOUT AS FORECAST THIS MORNING WITH LOW CLOUDS DISSIPATING AND ONLY
A FEW HIGH CLOUDS AFTER 121900Z. EXPECT A RETURN OF LOW CLOUDS WITH
BASES NEAR 1500 FEET MSL AND TOPS NEAR 2200 FEET MSL AFTER 131000Z.

THE MOUNTAINS AND DESERTS...EXPECT SCATTERED TO BROKEN CLOUDS AOA
10000 FEET MSL TODAY AND ISOLATED THUNDERSTORMS THIS AFTERNOON AFTER
122000Z WITH GUSTY AND ERRATIC WINDS NEAR STORMS. GREATEST RISK OF
THUNDERSTORMS SHOULD BE OVER BY 130500Z.

&&

.MARINE...
1000 AM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH SATURDAY.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

PUBLIC...PALMER
AVIATION/MARINE...PIERCE