Weather

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fxus66 kmtr 281713 
afdmtr 


Area forecast discussion 
National Weather Service San Francisco Bay area California 
1013 am PDT Thursday Aug 28 2008 


Discussion...the fickle finger of fog has stretched north along the 
coast up to San Mateo. However...the latest satellite imagery indicate that 
the fog is receding south and west. The latest feet Ord profiler indicate 
that the marine layer is only a few hundred feet deep...with temperatures 
just above the inversion at 29c. 


Temperatures this morning are running warmer than yesterday...in one case 
Livermore is reporting 90 degrees at 9 am! The gradient picture indicate 
a 5.3 mb northerly gradient between sfo-acv and only a 0.6 mb onshore 
gradient between sfo-SAC. The large scale sfo-wmc gradient is 
offshore at a robust 8.8 mb. 


No change to current thinking as it will be a hot day with temperatures 
well into the 90s and triple digits inland...80s and 90s along the 
bays...and 70s and 80s along the coast. A trough will move to the coast 
by the weekend...and deepen during the weekend. This will bring 
significant cooling to the district Sat...and especially Sunday. 


Models are indicate another round of offshore winds Monday...with the 
12z GFS hinting at the offshore flow continuing through the middle 
of next week...with the 00z Euro more bullish on the offshore flow. 
It is Worth noting that the models are indicate small breaks in the 
offshore flow next week...but for the most part it will be warm 
with little stratus. 


&& 


Fire weather...as of 10:00 am PDT Thursday...the red flag warnings 
for the north and East Bay hills has been extended through 8 PM 
Friday. The sea breeze kicks in on Friday with the winds turning 
more to the west and becoming gusty. Usually...these winds precede 
any relative humidity recovery so have decided to extend the red flag warnings. 


Will have to monitor the latest model runs as it looks like another 
offshore wind event could develop Sunday night into Monday morning. 
Models are hinting at a prolong period of offshore winds through 
the middle of next week. 


&& 


Aviation...as of 10:15 am PDT Thursday...high pressure is expected 
to prevail over the area for the duration of the forecast. This will 
result in hot dry conditions over the terminals. Therefore expect 
VFR to prevail across all San Francisco Bay and Monterey Bay area 
terminals. An onshore pressure gradient will result in generally 
light to moderate west northwest winds this afternoon across the 
area. 


&& 


Mtr watches/warnings/advisories... 
... Arena to Pigeon pt 20-60 nm and sf Bay. 
.Red flag warning for the North Bay and East Bay hills 
(zones 507 and 511) until 8 PM Friday. 
.Heat advisory for San Francisco...San Francisco Bay 
shoreline...East Bay interior valleys...and the Santa 
Clara Valley from noon through 8 PM Thursday. 
$$ 


Public forecast: mhs 
aviation/marine: Larry 
fire weather: r walbrun/mhs/Bell 


National Weather Service on the web at weather.Gov/sanfrancisco