Area Forecast Discussion
Issued by NWS San Diego, CA

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782
FXUS66 KSGX 221640
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 AM PDT FRI MAY 22 2015

.SYNOPSIS...A COLD UPPER LOW MOVING ACROSS SOUTHERN CALIFORNIA WILL
BRING SCATTERED SHOWERS TODAY. A THUNDERSTORM IS ALSO POSSIBLE. A
FEW LIGHT SHOWERS COULD LINGER INTO SATURDAY MORNING. IT WILL
CONTINUE TO BE WINDY IN PARTS OF THE MOUNTAINS AND DESERTS THROUGH
THIS EVENING. A SECOND UPPER LOW AND A DEEP MARINE LAYER WILL
CONTINUE THE COOL WEATHER THROUGH THE WEEKEND...BUT A WARMING TREND
WILL BEGIN MONDAY ONCE THE UPPER LOW SHIFTS EAST OUT OF THE AREA.
TEMPERATURES COULD BE BACK TO NEAR NORMAL LEVELS BY WEDNESDAY OR
THURSDAY WITH FAIR WEATHER PREVAILING. NIGHT AND MORNING LOW CLOUDS
WILL CONTINUE IN COASTAL AREAS NEXT WEEK THOUGH.

&&

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

SCATTERED SHOWERS WERE MOVING THROUGH...THOUGH MOSTLY IN SAN DIEGO
COUNTY. SOME BRIEF HEAVY RAIN HAS OCCURRED IN SAN DIEGO COUNTY.
HIGHEST PRECIPITATION AMOUNTS WERE AROUND ONE-HALF INCH NEAR PALOMAR
MOUNTAIN. OTHERWISE...SKIES WERE MOSTLY CLOUDY THIS MORNING FROM THE
MOUNTAINS WEST TO THE COAST...AND MANY OF THESE CLOUDS WILL LINGER
THIS AFTERNOON...ALONG WITH A FEW SHOWERS. TEMPS WILL CONTINUE WELL
BELOW NORMAL...WITH LOWER DESERT AREAS HAVING HIGHS FROM THE UPPER
70S TO BARELY 80...AND ANOTHER DAY OF MOSTLY 60S WEST OF THE
MOUNTAINS.

WATER VAPOR LOOP SHOWS THE UPPER LOW ALMOST OVERHEAD...AND THIS WILL
MOVE EAST TO THE COLORADO RIVER THIS AFTERNOON. PRECIP SHOULD
GRADUALLY DECREASE THIS AFTERNOON...BUT THE MODELS INDICATE A LOT OF
RESIDUAL MOISTURE OVER THE WEEKEND UNDER CONTINUED TROUGHING. THIS
COULD BRING AN ISOLATED SHOWER AGAIN SATURDAY MORNING AND POSSIBLY
EVEN SUNDAY MORNING...ESPECIALLY WITH A MORE VIGOROUS SHORTWAVE
MOVING SOUTH OVER THE SIERRA. THAT SHORTWAVE WILL PASS THROUGH
SUNDAY AND SHOULD BEGIN A CHANCE IN THE WEATHER AS THE MARINE LAYER
SHOULD GET MUCH MORE SHALLOW...AND RIDGING WILL BE ABLE TO DEVELOP
BEHIND THE TROUGH TO BRING A WARMING TREND STARTING MONDAY. TEMPS
WILL GRADUALLY INCREASE AND MAY ACTUALLY BE BACK TO NORMAL BY
WEDNESDAY OR THURSDAY...POSSIBLY EVEN A BIT ABOVE NORMAL IN THE
DESERTS. STRATUS WILL PROBABLY BE SPARSE SUNDAY NIGHT WITH THE
INVERSION SHIFT AFTER THE PASSAGE OF THE LOW BUT WITH ONSHORE FLOW
CONTINUING AND THE TIME OF YEAR...THE STRATUS SHOULD BECOME MORE
WIDESPREAD IN COASTAL AREAS AS THE WEEK GOES ON.

&&

.AVIATION...
221530Z...OVER AND WEST OF THE MOUNTAINS...THROUGH 1800 UTC...OVC-
BKN CLOUD DECKS IN THE 2000-8000 FT MSL LAYER WITH SCATTERED
SHOWERS...POSSIBLE THUNDERSTORMS...MTN OBSCURATION AND LOCAL VIS 3-5
SM IN SHOWERS. MOST SHOWER ACTIVITY AND BEST CHANCES FOR
THUNDERSTORMS WILL BE IN SAN DIEGO COUNTY. CB TOPS 25000 FT MSL.
1800-23/1500 UTC...SHOWERS GRADUALLY DIMINISHING...WITH CLOUD DECKS
BECOMING BKN-OVC IN THE 2500-6000 FT MSL LAYER. MTN OBSCURATION
CONTINUING.

HIGH DESERTS...MOSTLY UNRESTRICTED VIS THROUGH SATURDAY MORNING. BKN-
OVC CLOUDS IN THE 5000-8000 FT MSL LAYER AND MOSTLY UNRESTRICTED
VIS. CLOUDS GRADUALLY DIMINISHING AFTER 23/0900 UTC.

LOWER DESERTS...MOSTLY UNRESTRICTED VIS THROUGH SATURDAY MORNING.
SCT-BKN CLOUDS AOA 8000 FT MSL WITH LOCAL SCT CLOUDS IN THE 3500-
8000 FT MSL LAYER. CLOUDS GRADUALLY DIMINISHING AFTER 23/0000 UTC.

WEST WINDS 15-25 KT WITH GUSTS 30-40 KT OVER MTN
RIDGES...THROUGH/BELOW PASSES/CANYONS...DESERT MTN SLOPES AND INTO
ADJACENT DESERT AREAS WILL CREATE MOD-STG UDDFS/LLWS AND POSSIBLE
ROTORS OVER AND EAST OF THE MTNS.

&&

.MARINE...
830 AM...ISOLATED THUNDERSTORMS ARE POSSIBLE OVER THE COASTAL WATERS
THIS MORNING AS A LOW PRESSURE SYSTEM MOVES ACROSS THE REGION. SEE
THE MARINE WEATHER STATEMENT FOR DETAILS. OTHERWISE...NO HAZARDOUS
MARINE WEATHER IS EXPECTED THROUGH TUESDAY.

&&

.BEACHES...
830 AM...LONG-PERIOD SWELLS ORIGINATING FROM THE SOUTH PACIFIC WILL
REACH THE BEACHES OF SOUTHERN CALIFORNIA LATE SUNDAY...PEAK MONDAY
AT AROUND 3 FT/16 SECONDS...AND GRADUALLY LOWER TUESDAY INTO
WEDNESDAY. THE SWELLS ARE LIKELY TO PRODUCE STRONG RIP AND LONGSHORE
CURRENTS LATE SUNDAY THROUGH MONDAY...WITH SOME ELEVATED SURF IN
ORANGE COUNTY AND NORTHERN SAN DIEGO COUNTY.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...

CA...WIND ADVISORY UNTIL 9 PM PDT THIS EVENING FOR SAN DIEGO COUNTY
DESERTS-SAN GORGONIO PASS NEAR BANNING.

PZ...NONE.

&&

$$

PUBLIC...MAXWELL
AVIATION/MARINE/BEACHES...HARRISON



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