Flash Flood Watch 6, NWS San Diego, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
200 PM PDT TUE AUG 12 2014

.SYNOPSIS...
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP OVER
THE MOUNTAINS AND DESERTS THROUGH THIS EVENING...WITH ISOLATED FLASH
FLOODING POSSIBLE.  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 NEGATIVELY TILTED TROUGH MOVING INLAND
ACROSS NORTHERN CALIFORNIA AND THE PACIFIC NORTHWEST THIS
AFTERNOON.  MEANWHILE...SOUTHERN CALIFORNIA REMAINS ALONG A SHARP PW
GRADIENT...WITH SHOWERS AND THUNDERSTORMS DEVELOPING OVER THE
MOUNTAINS AND DESERTS.  AT THIS TIME...THE MOST IMPRESSIVE
THUNDERSTORM IS OVER THE HIGH DESERT...EAST OF LUCERNE VALLEY ALONG
247.  THIS STORM IS SHOWING A NICE INFLOW NOTCH AS WELL AS A
ROTATIONAL COUPLET...SO IT MAY BE PRODUCING A FUNNEL CLOUD OR
TORNADO.  A SPOTTER IN THE AREA DID REPORT NICKEL SIZE HAIL AND
HEAVY RAIN.  OTHER STORMS OVER THE MOUNTAINS ARE PRODUCING RAIN
RATES OF AN INCH OR GREATER PER HOUR.  THEREFORE...HAVE ISSUED A
FLASH FLOOD WATCH FOR THE MOUNTAINS AND DESERTS THROUGH THIS
EVENING...AND CURRENTLY...TWO FLASH FLOOD WARNING REMAIN IN EFFECT.
THIS THUNDERSTORM ACTIVITY WILL CONTINUE THROUGH THIS
EVENING...BEFORE GRADUALLY TAPERING OFF AFTER SUNSET.

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...
122000Z...THUNDERSTORMS ARE GOING UP IN THE MOUNTAINS AND PRODUCING
WIDESPREAD MID AND HIGH CLOUDS ACROSS AND ESPECIALLY IN THE EAST
PART OF THE AREA. LOW STRATUS HAS CLEARED EXCEPT FOR JUST OFF SHORE
AND ALONG THE IMMEDIATE COAST. EXPECT A RETURN OF LOW CLOUDS WITH
BASES NEAR 1200 FEET MSL AND TOPS NEAR 2200 FEET MSL BETWEEN 130300Z
AND 131000Z. STRATUS WILL BE A BIT SLOWER TO CLEAR WEDNESDAY MORNING
BUT LIKELY BETWEEN 131700Z TO 131900Z.

THE MOUNTAINS AND DESERTS...EXPECT SCATTERED TO BROKEN CLOUDS AOA
10000 FEET MSL AND SCATTERED THUNDERSTORMS WITH GUSTY AND ERRATIC
WINDS NEAR STORMS. GREATEST RISK OF THUNDERSTORMS SHOULD BE OVER BY
130500Z...THEN GENERALLY CLEAR SKIES.

&&

.MARINE...
100 PM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH SATURDAY.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH UNTIL 9 PM PDT THIS EVENING FOR THE APPLE AND
     LUCERNE VALLEYS...COACHELLA VALLEY...RIVERSIDE COUNTY
     MOUNTAINS...SAN BERNARDINO COUNTY MOUNTAINS...SAN DIEGO
     COUNTY DESERTS...SAN DIEGO COUNTY MOUNTAINS.

PZ...NONE.

&&

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