Weather Service Report


905 
FXUS66 KSGX 042049
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
200 PM PDT WED MAY 4 2016

.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL SLOWLY APPROACH FROM THE PACIFIC AND
RESULT IN COOLER WEATHER THURSDAY WITH SOME DRIZZLE OR LIGHT SHOWERS
POSSIBLE. MODERATELY STRONG WINDS WILL DEVELOP IN PARTS OF THE
MOUNTAINS AND DESERTS THURSDAY AND THURSDAY NIGHT. SHOWERS WILL
OCCUR AT TIMES THURSDAY NIGHT THROUGH SUNDAY...WITH GREATEST CHANCES
FRIDAY WHEN A FEW THUNDERSTORMS ARE POSSIBLE. TEMPERATURES WILL BE
BELOW NORMAL THURSDAY THROUGH SUNDAY. FAIR AND WARM WEATHER WILL
RETURN NEXT WEEK AS HIGH PRESSURE MOVES OVER THE WEST COAST.

&&

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

LOW CLOUDS ONLY PARTIALLY CLEARED THE COAST...BUT SKIES WERE MOSTLY
CLEAR INLAND. DUE TO THE MARINE LAYER...IT WAS MUCH COOLER WEST OF
THE MOUNTAINS...AS MUCH AS 15-20 DEG F LOWER IN PARTS OF THE INLAND
EMPIRE VERSUS 24 HOURS AGO...BUT SINCE THE PROFILE ABOVE THE MARINE
LAYER HAS NOT YET COOLED...THE DESERTS AND MOST MOUNTAIN AREAS HAD
SIMILAR TEMPS TODAY VERSUS TUESDAY...AS HIGH AS 98 AT THERMAL.

THE UPPER LOW IS NOW AROUND 33N/127W...AROUND 600 MI TO OUR WEST.
THE MODELS CONTINUE TO BE CONSISTENT WITH THE LOW...MOVING OVER FAR
SOUTHERN CALIFORNIA LATE FRIDAY. RIGHT NOW...THE MARINE LAYER LOOKS
MARGINALLY DEEP FOR PRECIP THU MORNING...SO MOST LIKELY DRIZZLE WILL
OCCUR FROM THE COASTAL MOUNTAIN SLOPES WEST TO THE COAST. THE
ONSHORE FLOW AND FURTHER DEEPENING OF THE MOIST LAYER WILL RESULT IN
SOME RAIN THURSDAY NIGHT/FRIDAY MORNING...WITH A TRANSITION TOWARDS
CONVECTIVE SHOWERS/ISOLATED THUNDERSTORMS DURING THE DAY FRIDAY AS
THE COLD CORE MOVES OVER...WITH -22 C AT 500 MB. BEST CHANCES WILL
BE OVER THE MOUNTAINS DUE TO THE HIGH SUN ANGLE...THOUGH DYNAMICS
COULD COMBINE WITH SOME INSTABILITY ALOFT TO BRING A FEW TSTORMS FRI
MORNING. THERE IS A RISK OF HAIL FRIDAY...MOSTLY 1/2 INCH OR
LESS...BUT UPPER LOWS IN MAY IN SOUTHERN CALIFORNIA CAN PRODUCE
LARGE HAIL. NEAR SATURATION OCCURS UP TO AROUND 600 MB
FRIDAY...WHICH IS GOOD FOR PRECIP. THE LOW WILL MOVE TO THE
NORTHEAST SAT/SUN...BUT ENOUGH MOISTURE AND SOME INSTABILITY WILL
KEEP THE CHANCE OF SHOWERS SAT...AND A SLIGHT CHANCE SUNDAY. AFTER
FRIDAY...MOST OF THE ACTIVITY WILL BE INLAND...CLOSER TO THE
LOW...AND WITH BETTER INSTABILITY AIDED BY THAT SUN ANGLE.
OVERALL...PRECIP AMOUNTS SHOULD BE 1/4 TO 1/2 INCH...WITH LOCAL
AMOUNTS OVER 1 INCH IN THE MOUNTAINS FROM THURSDAY NIGHT THROUGH
SUNDAY. SOME WIND WILL OCCUR THU/THU NIGHT IN THE
MOUNTAINS/DESERTS...WITH ISOLATED GUSTS TO NEAR 60 MPH ON THE DESERT
SLOPES...WHEN SOME TEMPERATURE GRADIENTS WILL STILL BE IN
PLACE...BUT AFTER THAT...WINDS WILL BE SOMEWHAT LIGHTER AS THE
CLOSED LOW WILL RESULT IN WEAKER GRADIENTS. A WIND ADVISORY WILL BE
ISSUED FOR SOME MOUNTAIN/DESERT LOCATIONS 3 PM FRIDAY-5 AM SATURDAY.
SNOW LEVELS WILL MOSTLY BE AROUND 7000 FEET...WITH SEVERAL INCHES
OF SNOW POSSIBLE AT HIGHEST ELEVATIONS.

HIGH PRESSURE ALOFT WILL BRING FAIR AND WARMER WEATHER EXCEPT FOR
SOME NIGHT/MORNING COASTAL STRATUS EARLY NEXT WEEK.

&&

.AVIATION... 
042030Z...COASTS/VALLEYS...BKN/OVC LOW CLOUDS WITH BASES BETWEEN
1400-1800 FT MSL AND TOPS 2200 FT MSL CONTINUE TO HUG THE IMMEDIATE
COAST. INLAND...FEW HIGH CLOUDS AOA 15000 FT MSL WILL SLIDE OVER THE
REGION THROUGH TONIGHT. CLOUD BASES WILL GRADUALLY RISE TO AROUND
2000 FT MSL AND PUSH INLAND AGAIN AFT 05/0200Z. VIS WILL DROP TO 3-5
SM WHERE THESE CLOUDS INTERSECT TERRAIN ALONG THE LOWER COASTAL
SLOPES. LIGHT DRIZZLE WILL ALSO BE POSSIBLE LATE TONIGHT FROM THE
COAST TO THE MOUNTAINS.

MOUNTAINS/DESERTS...AS THE MARINE LAYER DEEPENS...MAINLY AFT
05/0200Z...MOUNTAINS WILL BECOME OBSCURED. THIS SCENARIO WOULD LOWER
VIS BELOW 3 MILES AT TIMES. IN THE DESERTS...EXPECT SCT CLOUDS AOA
15000 FT MSL AND UNRESTRICTED VIS THROUGH TONIGHT. SOUTH SOUTHWEST
WINDS IN THE SAN BERNARDINO MOUNTAINS AND UPPER DESERTS AND WEST
SOUTHWEST WINDS IN THE SAN DIEGO COUNTY MOUNTAINS/RIVERSIDE COUNTY
MOUNTAINS AND LOWER DESERTS WILL BECOME GUSTY AT TIMES AFT 04/2200Z
THIS AFTERNOON.

&&

.MARINE... 
130 PM...A STORM SYSTEM WILL BRING A SLIGHT CHANCE OF THUNDERSTORMS
FRIDAY MORNING THROUGH LATE FRIDAY AFTERNOON. THESE STORMS COULD
PRODUCE CLOUD TO WATER LIGHTNING AND BRIEF GUSTY WINDS.
OTHERWISE...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH SATURDAY.


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...WIND ADVISORY FROM 3 PM THURSDAY TO 5 AM PDT FRIDAY FOR 
     RIVERSIDE COUNTY MOUNTAINS-SAN DIEGO COUNTY DESERTS-SAN 
     DIEGO COUNTY MOUNTAINS-SAN GORGONIO PASS NEAR BANNING.
PZ...NONE.

&&

$$

PUBLIC...MAXWELL
AVIATION/MARINE...JT

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