FXUS66 KSGX 281620 CCA
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
820 AM PST SAT NOV 28 2009
.SYNOPSIS...UPPER LEVEL LOW WAS MOVING INTO SOUTHERN CALIFORNIA THIS
MORNING AND WILL CONTINUE TO MOVE SLOWLY TO THE SOUTHEAST THROUGH
THE AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS WILL DECREASE
THIS EVENING. MOISTURE WILL ROTATE AROUND THE LOW AS IT DROPS SOUTH
AND SHOWERS MAY CONTINUE MAINLY OVER THE MOUNTAINS THROUGH SUNDAY
AFTERNOON. THE SNOW LEVEL WILL DROP TO AROUND 4500 FEET AND LOCALLY
LOWER WITH AROUND 3 TO 6 INCHES OF SNOW IN THE HIGHER ELEVATIONS.
GUSTY NORTH WINDS WILL DEVELOP LATE TONIGHT AND BECOME NORTHEAST
SUNDAY THROUGH MONDAY MORNING WITH A WEAK FLOW MONDAY AFTERNOON
THROUGH FRIDAY. HIGH PRESSURE ALOFT MOVES OVER LATE SUNDAY THROUGH
TUESDAY...WEAKENING WEDNESDAY...INCREASING THURSDAY AND FRIDAY.
&&
.DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO...
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.
UPPER LOW APPEARS TO BE MOVING INTO SOUTHERN CALIFORNIA THIS MORNING
AND CLOSE TO THE TRACK OF THE 12Z NAM MODEL FROM SATURDAY. WIDE
SPREAD SHOWERS AND ISOLATED THUNDERSTORMS WERE SHOWING UP ON RADAR
AND NUMEROUS SPOTTER REPORTS OF SNOW IN THE MOUNTAINS SO FAR THIS
MORNING. MOST RAINFALL AMOUNTS SO FAR HAVE BEEN BETWEEN A TENTH AND
A QUARTER OF AN INCH BUT THERE WERE SOME REPORTS OF OVER AN INCH
NEAR DEVORE AND ALONG THE SOUTHWEST SLOPES OF THE SAN BERNARDINO
MOUNTAINS. BASED ON LIGHTNING DETECTION...THUNDERSTORMS WERE
CONFINED TO THE SAN BERNARDINO MOUNTAINS AND THE INLAND EMPIRE
ALTHOUGH THERE WAS A REPORT OF LIGHTNING AND THUNDER NEAR POWEY IN
SAN DIEGO COUNTY BUT LIGHTNING DETECTION IN THAT AREA HAS BEEN
LACKING OVER THE PAST SEVERAL EVENTS.
THE NEW 12Z NAM12 MODEL CONTINUES TO INDICATE THE UPPER LOW WILL BE
TO THE SOUTHEAST AND THE LAST VORT LOBE SHOULD PASS THROUGH THE AREA
THIS EVENING. HOWEVER...THERE IS ENOUGH MOISTURE TO THE NORTH AND
SHOULD BE ENOUGH WRAP AROUND MOISTURE TO KEEP UPSLOPE PRECIPITATION
OVER THE NORTH SIDE OF THE SAN BERNARDINO MOUNTAINS AND RIVERSIDE
COUNTY MOUNTAINS INTO MID MORNING ON SUNDAY.
NORTH TO NORTHEAST WINDS SHOULD DEVELOP LATE TONIGHT AND SUNDAY
MORNING ACROSS THE SAN BERNARDINO MOUNTAINS AND BELOW PASSES AND
CANYONS. WINDS BECOME NORTHEAST SUNDAY NIGHT AND MONDAY BUT BASED ON
LOCAL WIND STUDIES...WIND COULD REACH WIND ADVISORY LEVELS SUNDAY
AND MONDAY BUT NOT HIGH WIND CRITERIA.
MEDIUM RANGE MODELS CONTINUE TO SHOW RIDGING FOR MONDAY AND TUESDAY
BUT MODELS ARE IN DISAGREEMENT ON THE TRACK AND STRENGTH FOR THE
SHORTWAVE MOVING IN ON WEDNESDAY. AT THIS TIME...WILL LEAN TOWARDS
SOME DEEPENING OF THE MARINE LAYER AND PARTLY CLOUDY CONDITIONS
ELSEWHERE. THIS SHORTWAVE WILL BE FOLLOWED BY MORE RIDGING FOR DRY
CONDITIONS INTO NEXT WEEKEND.
NO UPDATES ARE PLANNED AT THIS TIME.
&&
.AVIATION...
281613Z...UNSTABLE CONDITIONS OVER THE AREA TODAY AS LOW PRESSURE
MOVES FROM NORTH TO SOUTH. EXPECT VARIABLE CIGS WITH LAYERS BTWN
FL030 AND FL100 AND ISOLATED CBS WITH TOPS TO FL250. IFR CIGS AND
VIS SHOULD BE SHORT-LIVED AND ASSOCIATED WITH THE HEAVIER CONVECTIVE
CELLS. OTHERWISE MOSTLY VFR...EXCEPT FOR THE COASTAL MOUNTAIN SLOPES
WHERE UPSLOPE FLOW WILL KEEP THE TERRAIN OBSCURED. WEST WINDS 25 TO
35 KTS WITH LOCAL GUSTS OF 45-50 KT OVER THE RIDGES WILL CREATE
MOUNTAIN WAVE ACTIVITY AND ASSOCIATED UP AND DOWNDRAFTS THROUGH
ABOUT 22Z.
ADDITIONAL MOISTURE AND PRECIPITATION WILL MOVE INTO THE SAN
BERNARDINO MOUNTAINS AFTER 03Z SUN WITH NE UPSLOPE FLOW. CLOUDS AND
PRECIPITATION WILL OBSCURE THE HIGHER TERRAIN. OTHERWISE SCT-BKN
CIGS ABOVE FL060 EXPECTED OVER THE REMAINDER OF SW CA WITH SOME
LIGHT SHOWERS POSSIBLE THROUGH THE NIGHT
&&
.MARINE...
A 10 TO 12 FT WNW SWELL WILL MOVE THROUGH PORTIONS OF THE COASTAL
WATERS TODAY AND TONIGHT...THEN DECREASE ON SUN. WINDS OF 20 KTS
WITH GUSTS AS HIGH AS 30 KTS ARE OCCURRING THIS MORNING. THE
COMBINATION OF WIND AND SWELL WILL PUSH COMBINED SEAS TO BETWEEN 12
AND 15 FT AT TIMES THIS MORNING. THE WINDS AND WIND WAVES SHOULD
DECREASE THIS AFTERNOON. A HIGH SURF ADVISORY IS IN EFFECT FOR SURF
OF 5 TO 7 FEET WITH MAX SETS TO 10 FT OR MORE. THE SURF SHOULD
DECREASE RAPIDLY ON SUN. ISOLATED THUNDERSTORMS ARE STILL
POSSIBLE...MAINLY THIS MORNING.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...WINTER WEATHER ADVISORY FOR THE SAN BERNARDINO MOUNTAINS UNTIL
3 PM SATURDAY.
HIGH SURF ADVISORY UNTIL 2 PM PST SUNDAY FOR ORANGE AND SAN
DIEGO COUNTY COASTAL AREAS.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS TO MIDNIGHT FOR THE
INNER WATERS AND UNTIL 8 AM PST SUNDAY FOR THE OUTER WATERS.
&&
$$
PUBLIC...HORTON
AVIATION/MARINE...JAD
