Area Forecast Discussion
Issued by NWS San Diego, CA

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FXUS66 KSGX 061708
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
1008 AM PDT FRI MAY 6 2016

.MORNING UPDATE...

WIDESPREAD SHOWERS CONTINUE ACROSS SAN DIEGO COUNTY THIS MORNING.
SOME ACTIVITY IS FINALLY STARTING TO FIRE UP IN ORANGE COUNTY AND
THE SOUTHERN INLAND EMPIRE. BY THIS AFTERNOON WE WILL SEE SHOWERS
BREAKING OUT ACROSS THE NORTHERN MOUNTAINS AS WELL AS THE BROAD
UPPER LOW BEGINS TO SLOWLY CHUG TO THE EAST.

A FLASH FLOOD WATCH REMAINS IN EFFECT FOR THIS AFTERNOON ONCE THE
UPPER LOW STARTS TO KICK EAST. ISOLATED REPORTS OF FLOODING WILL BE
POSSIBLE UNDER THE HEAVIER SHOWERS.

A VERY MOIST BUT NOT ESPECIALLY UNSTABLE ATMOSPHERIC PROFILE IS
NOTED THIS MORNING ON THE 12Z RAOB FROM MIRAMAR. THE SOUNDING IS
QUASI-TROPICAL. THIS IS NOT ESPECIALLY CONDUCIVE TO ORGANIZED
CONVECTION ALTHOUGH A FEW THUNDERSTORMS WILL BE POSSIBLE THIS
AFTERNOON AND COULD CONTRIBUTE TO BRIEF HEAVY RAIN RATES.

SHOWER ACTIVITY WILL DIMINISH THIS EVENING RENEWED SHOWER ACTIVITY
IS EXPECTED TOMORROW DUE TO WRAP AROUND MOISTURE FROM THE UPPER LOW
AS IT WILL BE SITUATED OVER ARIZONA...ALTHOUGH COVERAGE WILL BE MUCH
LESS THAN WHAT WE`VE SEEN THIS MORNING.

RAINFALL REPORTS HAVE BEEN ISSUED FOR THE RAINFALL EVENT SO FAR THIS
MORNING. THE HEAVIEST REPORTS HAVE BEEN IN THE SOUTHERN SAN DIEGO
COUNTY FOOTHILLS WITH UP TO ONE INCH OF RAIN SO FAR...AND GENERALLY
AROUND ONE-HALF INCH FOR THE SAN DIEGO METRO AREA.

&&

.SYNOPSIS...
A SLOW MOVING LOW PRESSURE SYSTEM WILL BRING PERIODS OF SHOWERS
AND ISOLATED THUNDERSTORMS THROUGH EARLY EVENING...DECREASING
DURING THE WEEKEND. WARMER AND DRY FOR NEXT WEEK. THE MARINE LAYER
AND WEAK ONSHORE FLOW WILL KEEP COASTAL AREAS COOLER WITH AREAS OF
NIGHT AND MORNING LOW CLOUDS AND FOG. THE ONSHORE FLOW WILL ALSO
BRING GUSTY WEST WINDS TO THE MOUNTAINS AND DESERTS EACH LATE
AFTERNOON THROUGH LATE EVENING.

&&

.PREVIOUS DISCUSSION (ISSUED AT 344 AM PDT)...FOR EXTREME
SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN
RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

.SHORT TERM (TODAY THROUGH SUNDAY)...
A SLOW MOVING CLOSED LOW PRESSURE SYSTEM CENTERED OVER SOUTHERN
CALIFORNIA WILL MOVE INTO THE CENTRAL ROCKIES THROUGH SUNDAY.
EARLY THIS MORNING...A SHORTWAVE OFF THE NORTHERN BAJA COAST WAS
ENHANCING SHOWERS OVER THE COASTAL WATERS AND ADJACENT COASTAL
AREAS OF NORTHERN BAJA AND FAR SOUTHERN CALIFORNIA...MAINLY
CENTRAL AND SOUTHERN PORTIONS OF COASTAL SAN DIEGO COUNTY.
OVERNIGHT THROUGH 3 AM...GREATEST RAINFALL AMOUNTS HAVE BEEN NEAR
THE COAST OF SAN DIEGO FROM JUST NORTH OF LA JOLLA TO AROUND DEL
MAR WITH ONE THIRD INCH OR MORE OF RAINFALL IN THESE AREAS WITH
THE GREATEST AMOUNT OF AROUND 0.6 INCH NEAR DEL MAR. FOR THE NEXT
FEW HOURS...THE MOST WIDESPREAD SHOWER COVERAGE IS EXPECTED OVER
CENTRAL AND SOUTHERN COASTAL AREAS OF SAN DIEGO COUNTY EXTENDING
INTO THE WESTERN VALLEYS. GIVEN THE RAINFALL THAT HAS ALREADY
OCCURRED...HEAVIER DOWNPOURS HAVE THE POTENTIAL TO CAUSE LOCAL
URBAN FLOODING...ESPECIALLY IN POORLY DRAINED AREAS.

FOR THIS AFTERNOON AND EARLY EVENING...THE HIGHER RESOLUTION
MODELS SHIFT THE GREATER SHOWER AND ISOLATED THUNDERSTORM
COVERAGE TO THE MOUNTAINS...DESERTS...AND INLAND VALLEYS WITH
GREATEST COVERAGE AND RAINFALL AMOUNTS OVER THE MOUNTAINS. A
FLASH FLOOD WATCH HAS BEEN ISSUED FOR THE MOUNTAINS AND DESERTS
FOR THIS AFTERNOON AND EARLY EVENING.

THE CHANCE OF SHOWERS AND SLIGHT CHANCE OF THUNDERSTORMS WILL
CONTINUE FOR SATURDAY AFTERNOON AND EARLY EVENING...MAINLY IN THE
MOUNTAINS...DESERTS...AND INLAND VALLEYS WITH A SLIGHT CHANCE OF
SHOWERS FOR THE MOUNTAINS SUNDAY AFTERNOON AND EARLY EVENING.
OTHERWISE...THERE WILL BE SCATTERED SHOWERS...MAINLY FOR
COASTAL...VALLEY...AND MOUNTAIN AREAS OF SAN DIEGO COUNTY FOR
TONIGHT INTO SATURDAY MORNING...WITH LESSER COVERAGE FOR SATURDAY
NIGHT INTO EARLY SUNDAY MORNING.

SNOW LEVELS WILL MOSTLY FLUCTUATE BETWEEN 6500 AND 7000 FEET WITH
SEVERAL INCHES OF SNOW POSSIBLE ABOVE 7500 FEET.

COOLER TEMPERATURES FOR TODAY WILL BEGIN TO SLOWLY WARM FOR
SATURDAY AND SUNDAY. GUSTY WEST WINDS IN THE MOUNTAINS AND DESERTS
OF RIVERSIDE AND SAN DIEGO COUNTIES WILL GRADUALLY WEAKEN THIS
MORNING.

&&

.LONG TERM (MONDAY THROUGH THURSDAY)...
HIGH PRESSURE ALOFT NEAR THE WEST COAST WILL BRING DRY AND WARMER
WEATHER INLAND AREAS. THE MARINE LAYER AND WEAK ONSHORE FLOW WILL
KEEP COASTAL AREAS COOLER WITH AREAS OF NIGHT AND MORNING LOW
CLOUDS AND FOG.

&&

.AVIATION...
061530Z...COASTS/VALLEYS...BKN-OVC WITH BASES 3500-5000 FT WITH
LAYERS AND SOME TOPS TO 20000 FT MSL. SHRA AND ISOLATED TSRA WILL
CONTINUE THROUGH 07/0600Z...THEN SHRA CONTINUING OVERNIGHT. BASES
LOCALLY LOWERING TO BETWEEN 1500-2500 FT MSL WITH 2-4SM VIS IN
HEAVIER CELLS. SHRA COVERAGE WILL BE DECREASING THIS EVENING INTO
TONIGHT WITH BKN/OVC CONTINUING...SIMILAR BASES AND TOPS TO THIS
MORNING.

MOUNTAINS/DESERTS...SHOWERS AND ISOLATED THUNDERSTORMS CONTINUING TO
DEVELOP THIS MORNING AND INTO FRIDAY EVENING. VIS WILL BE REDUCED IN
HEAVIER SHOWERS AND COASTAL SLOPES OF THE MOUNTAINS WILL REMAIN
OBSCURED IN CLOUDS/PRECIP. SHOWERS WILL GRADUALLY TAPER OFF LATE
THIS EVENING. WESTERLY WINDS STRENGTHENING THIS EVENING AFT
06/0000Z...GUSTING TO 25 TO 35 MPH IN THE MORE WIND PRONE AREAS.

&&

.MARINE...
830 AM...A PACIFIC STORM WILL BRING A SLIGHT CHANCE OF THUNDERSTORMS
THROUGH LATE THIS AFTERNOON. THESE STORMS COULD PRODUCE CLOUD TO
WATER LIGHTNING AND BRIEF GUSTY WINDS. OTHERWISE...NO HAZARDOUS
MARINE WEATHER IS EXPECTED SATURDAY THROUGH TUESDAY.

&&

.SKYWARN...
SKYWARN ACTIVATION MAY BEEN NEEDED FOR THE MOUNTAINS AND DESERTS
FOR THIS AFTERNOON AND EARLY EVENING. WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH FROM NOON PDT TODAY THROUGH THIS EVENING FOR
     APPLE AND LUCERNE VALLEYS-COACHELLA VALLEY-RIVERSIDE COUNTY
     MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS-SAN DIEGO COUNTY
     DESERTS-SAN DIEGO COUNTY MOUNTAINS-SAN GORGONIO PASS NEAR
     BANNING.

PZ...NONE.
&&

$$

PUBLIC...17/JMB
AVIATION/MARINE...JT



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