Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

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000
FXUS66 KMTR 310555
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1055 PM PDT SUN AUG 30 2015

.SYNOPSIS...GENERALLY DRY WEATHER CONDITIONS WILL PERSIST ACROSS THE
REGION THROUGH THE UPCOMING WORK WEEK. DAYTIME TEMPERATURES NEAR
THE COAST WILL CONTINUE TO BE NEAR NORMAL...WHILE INLAND AREAS
WILL BE SLIGHTLY BELOW SEASONAL AVERAGES.

&&

.DISCUSSION...AS OF 8:35 PM PDT SUNDAY...A DRY SHORTWAVE TROUGH
SWEPT ACROSS NORTHERN CALIFORNIA THIS AFTERNOON. BEHIND THIS
TROUGH...LOCALLY GUSTY WEST TO NORTHWEST WINDS DEVELOPED. WINDS
WERE GUSTING AS HIGH AS 37 MPH AT SAN FRANCISCO AIRPORT THIS
EVENING. THESE BRISK WINDS HAVE RESULTED IN GOOD LOW LEVEL MIXING
AND HAVE HELPED LIMIT COASTAL LOW CLOUD FORMATION THIS EVENING.
EXPECT LOW CLOUDS TO INCREASE SOMEWHAT OVERNIGHT AS WINDS
EASE...BUT LOW CLOUDS AND NOT EXPECTED TO BECOME WIDESPREAD. A
FORECAST UPDATE EARLIER THIS EVENING INCLUDED A REDUCTION IN LOW
CLOUDS LATE TONIGHT AND MONDAY MORNING...ESPECIALLY FOR INLAND
AREAS.

WINDS BEHIND THE SHORTWAVE TROUGH HAD ENOUGH OF A NORTHERLY
COMPONENT TO PRODUCE DOWNSLOPE WARMING IN THE NORTH BAY VALLEYS
THIS AFTERNOON. THE SONOMA COUNTY AIRPORT HAD AN AFTERNOON HIGH OF
90 DEGREES...WHICH WAS THE WARMEST SPOT IN THE BAY AREA TODAY.

LITTLE CHANGE IS FORECAST THROUGH MONDAY. TEMPERATURES ARE
FORECAST TO BE NEAR SEASONAL NORMS AND MOST SUNNY SKIES WILL
PREVAIL AFTER PATCHY MORNING LOW CLOUDS CLEAR.

AN UPPER LEVEL TROUGH CURRENTLY CENTERED NEAR THE ALASKAN
PANHANDLE IS FORECAST TO GRADUALLY DIG SOUTH ALONG THE WEST COAST
THROUGH MIDWEEK. NIGHT AND MORNING LOW CLOUDS WILL PROBABLY BECOME
MORE WIDESPREAD FROM MONDAY NIGHT THROUGH WEDNESDAY MORNING...AND
PATCHY LATE NIGHT AND EARLY MORNING COASTAL DRIZZLE IS POSSIBLE.
OTHERWISE...NO PRECIPITATION IS EXPECTED. TEMPERATURES WILL
LIKELY DIP BELOW NORMAL BY MIDWEEK...ESPECIALLY ACROSS INLAND
AREAS.

THE MEDIUM RANGE MODELS AGREE THAT THE UPPER TROUGH WILL LIFT TO
THE NORTHEAST LATE IN THE WEEK...ALLOWING FOR A WARMING TREND
NEXT WEEKEND.

&&

.AVIATION...AS OF 10:42 PM PDT SUNDAY...THE MESOSCALE MODEL
OUTPUT IS STILL HAVING TROUBLE RESOLVING THE PRESENT STRENGTH OF
THE NORTHERLY SURFACE PRESSURE GRADIENT OVER THE NORTH BAY AS WELL
AS FROM ACV-SFO. BOTH GRADIENTS HAVE CLIMBED THROUGH THE AFTERNOON
AND EVENING FOLLOWING THE PASSAGE OF THE DRY TROUGH EARLIER. THE
UKI-STS GRADIENT IS HOLDING STRONG AT 2.6 MB AND THE ACV-SFO IS
MODERATE AT 4.4 MB. BOTH ARE FORECAST TO HOLD CLOSE TO WHERE THEY
ARE OVERNIGHT. AN INDICATION OF NORTHERLY WIND POTENTIAL...DRYING
DOWNSLOPING NORTHERLY WINDS SHOULD CONTINUE OVERNIGHT DUE TO THESE
GRADIENTS THEREBY GREATLY REDUCING THE CHANCES OF STRATUS AND/OR
FOG DEVELOPMENT ESPECIALLY OVER THE INTERIOR NORTH BAY. SATELLITE
AND AREA OBSERVATIONS SHOW CLEAR TO MOSTLY CLEAR SKIES AREA-WIDE.
A FEW PATCHES OF STRATUS OR FOG ARE STILL POSSIBLE ALONG THE
IMMEDIATE COAST OVERNIGHT. VFR IS VERY LIKELY MONDAY.

VICINITY OF KSFO...VFR. WESTERLY WINDS HAVE SUBSIDED THIS EVENING
BUT STILL COULD PICK UP AT TIMES OVERNIGHT. GENERAL THOUGHT IS THAT
THE WIND SPEEDS WILL REMAIN BELOW 20 KNOTS. HOWEVER BY MONDAY AFTERNOON
WESTERLY WINDS WILL LIKELY PICK BACK UP AGAIN WITH GUSTS TO 20-25 KNOTS
21Z-04Z.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...VFR.

&&

.MARINE...AS OF 8:42 PM PDT SUNDAY...A TROUGH OF LOW PRESSURE WILL
CONTINUE TO MOVE SOUTH OVER THE COASTAL WATERS TONIGHT. GUSTY
NORTHWEST WINDS WILL CONTINUE OVER THE COASTAL WATERS THROUGH
MONDAY EVENING.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TNGT...SCA...PT ARENA TO PT REYES 0-10 NM
             SCA...PT REYES TO PIGEON PT 0-10 NM
             SCA...PT ARENA TO PIGEON PT 10-60 NM
             SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM
             SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM

&&

$$

PUBLIC FORECAST: DYKEMA
AVIATION/MARINE: CANEPA


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