Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 301637
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
937 AM PDT THU OCT 30 2014

.SYNOPSIS...
NEAR NORMAL WEATHER IS FORECAST TODAY AND EARLY FRIDAY...WITH
SOME MID AND HIGH LEVEL CLOUDS. THE FIRST WINTER STORM OF THE
SEASON WILL MOVE ACROSS SOUTHWESTERN CA LATE FRIDAY THROUGH EARLY
SUNDAY. RAIN AND HIGH ELEVATION SNOW SHOWERS...WINDY CONDITIONS IN
THE MOUNTAINS AND DESERTS...AND A DEEP MARINE LAYER IS EXPECTED OVER
THE REGION. HIGH PRESSURE WILL DEVELOP NEXT WEEK...WITH WARMER
DAYS AND WEAK TO MODERATE OFFSHORE FLOW EARLY TO MID NEXT WEEK.

&&

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

AT 9 AM PDT...WATER VAPOR SATELLITE IMAGERY DISPLAYED A WEAK
UPPER-LEVEL RIDGE OVER THE FOUR CORNERS REGION...A WEAK UPPER-
LEVEL LOW JUST OFFSHORE FROM SOUTHERN CA...AND A UPPER-LEVEL
TROUGH MOVING SOUTHEAST OVER OREGON AND WASHINGTON STATE. VISIBLE
SATELLITE SHOWED WIDESPREAD MID AND HIGH CLOUDS OVER THE AREA.
HIGHS WILL BE FROM NEAR NORMAL TO SLIGHTLY ABOVE NORMAL
TODAY...WITH CONTINUED HIGH CLOUDS.

THE 30/0600 UTC MODEL SOLUTIONS ARE IN RELATIVELY GOOD AGREEMENT
WITH THE FORECAST THROUGH THE SHORT-TERM...AND SLIGHTLY DIFFER IN
THE LONG-TERM. HIGHS JUST BELOW NORMAL WEST OF THE MOUNTAINS TO
JUST ABOVE NORMAL IN THE MOUNTAINS AND DESERTS ARE FORECAST FRIDAY
AS ONSHORE FLOW STRENGTHENS AND THE MARINE LAYER DEEPENS WITH
APPROACHING LOW PRESSURE. LOW CLOUDS AND FOG WILL PUSH INTO THE
INLAND VALLEYS BY LATE FRIDAY MORNING.

THE WEATHER WILL DETERIORATE FRIDAY NIGHT THROUGH SATURDAY AS AN
UPPER-LEVEL TROUGH MOVES THROUGH THE REGION. THE MAIN BAND OF
PRECIPITATION WILL ENTER THE NORTHERN PART OF THE CWA LATE FRIDAY
NIGHT...AND CONTINUE SOUTHEAST ACROSS THE AREA THROUGH SATURDAY
MORNING. PRECIPITATION IS FORECAST TO BE LIGHT ACROSS MOST OF SW
CA SINCE THE BRUNT OF THE ENERGY ASSOCIATED WITH THE SYSTEM WILL
REMAIN JUST TO OUR NORTH...AND THE ATMOSPHERIC RIVER PLUME WILL
ONLY CONTAIN AROUND 1 INCH OF PRECIPITABLE WATER. ALTHOUGH THE
MAIN FRONT WILL MOVE THROUGH EARLY SATURDAY...LIGHT SHOWERS WILL
BE POSSIBLE THROUGH EARLY SUNDAY AS A FEW WEAK WAVES MOVE ACROSS
THE AREA AND ISLAND BANDING DEVELOPS. SNOW LEVELS WILL BE JUST
ABOVE 7000 FT WHEN PRECIPITATION BEGINS LATE FRIDAY NIGHT...AND
LOWER DOWN TO AROUND 6000 FT BY LATE SATURDAY MORNING.

...FORECAST PRECIPITATION AMOUNTS FOR THIS WEEKEND ARE...
HIGH DESERTS....LESS THAN 0.10 INCH
COAST/VALLEYS...0.10 TO 0.25 INCH
MOUNTAINS.......0.50 TO 1.00 INCH

...FORECAST SNOWFALL FOR THE MOUNTAINS THIS WEEKEND...
6500-7500 FT...1 TO 2 INCHES
7500+ FT.......3 TO 5 INCHES...HIGHER AMOUNTS ON MOUNTAIN PEAKS

COLDER AIR WILL FOLLOW THE FRONT AS FORECAST HIGHS ON SATURDAY AND
SUNDAY DIP DOWN 5 TO 10 DEGREES F BELOW NORMAL ALONG THE
COAST...TO 10 TO 20 DEGREES F BELOW NORMAL INLAND. A TIGHT
PRESSURE GRADIENT WITH THE FRONTAL PASSAGE WILL PROVIDE UPPER-
LEVEL SUPPORT TO GENERATE WINDY CONDITIONS OVER THE MOUNTAINS AND
DESERTS. WEST TO SOUTHWEST WIND GUSTS WILL BE BETWEEN 30 TO 50
MPH...WITH LOCAL GUSTS TO 65 MPH POSSIBLE OVER MOUNTAIN PEAKS.
STRONGEST WINDS WILL BE OBSERVED ON SATURDAY MORNING.

SURFACE HIGH PRESSURE WILL THEN BUILD OVER THE GREAT BASIN EARLY
MONDAY THROUGH THE MIDDLE OF NEXT WEEK. THIS WILL CREATE WEAK TO
MODERATE OFFSHORE FLOW...A SHALLOW MARINE LAYER...LOW INLAND
MINIMUM RELATIVE HUMIDITY VALUES...AND HIGHS 5 TO 10 DEGREES F
ABOVE NORMAL BY NEXT WEDNESDAY. TEMPERATURES WILL SLOWLY RISE EACH
DAY FROM MONDAY THROUGH MID NEXT WEEK AS AN UPPER-LEVEL RIDGE
SLOWLY BUILDS OVER SW CA FROM THE WEST BY WEDNESDAY.

&&

.AVIATION...
301515Z...VARIABLE HIGH CLOUDS AOA 15000 FEET MSL WILL SPREAD ACROSS
THE ENTIRE REGION TODAY. MORE WIDESPREAD LOW CLOUDS...BASED AROUND
1500 FEET MSL...WILL DEVELOP AT COASTAL AIRPORTS BETWEEN 31/02-06Z
THIS EVENING...SPREADING INTO LOWER VALLEYS OVERNIGHT AND REACHING
KONT BY AROUND 31/09Z. AREAS OF VIS 3-5 SM IN BR/HZ LIKELY IN INLAND
VALLEYS AND WHERE CLOUDS MEET HIGHER TERRAIN. BRIEF SCATTERING OF
LOW CLOUDS IS EXPECTED FRIDAY MORNING BEFORE HIGHER...MORE
EXTENSIVE...CLOUD COVER MOVES IN WITH THE APPROACHING WEATHER SYSTEM.

&&

.MARINE...
815 AM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH FRIDAY.
A COLD FRONT MOVING THROUGH SOUTHERN CALIFORNIA WILL BRING STRONG
WINDS AND STEEP WAVES TO THE COASTAL WATERS ON SATURDAY...WHICH
WOULD BE HAZARDOUS FOR SMALL CRAFT IN THE OUTER COASTAL WATERS.
CONDITIONS WILL IMPROVE EARLY SUNDAY.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

$$

PUBLIC...JJT
AVIATION/MARINE...TS







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