Area forecast discussion
National Weather Service San Francisco Bay area
238 am PDT Thursday may 23 2013
Discussion...as of 2:38 am PDT Thursday...cool temperatures and
breezy conditions are expected across the forecast area once again
today as a result of a low pressure system centered over the
Pacific northwest. This low pressure system is advecting cool
marine air into the forecast area and is expected to linger around
through the end of the week.
As previously stated a low pressure system is centered over the
Pacific northwest this morning. Another low pressure system in
apparent on the current satellite water vapour image entering
the Bering Sea. Both the 0000z GFS and European model (ecmwf) have initialized well
with these features pushing the Pacific northwest low northeast
into Canada Saturday. Both models continue to depict a cool troughy
pattern over our forecast area through the weekend. Both models
then introduce a new trough of low pressure moving towards the West
Coast Monday bringing a possibility of rain to northern portions
of the forecast area by late Monday morning. At this point it looks
like rain will arrive to the North Bay area late Monday morning
spreading south to San Francisco by late afternoon and Monterey by
early evening. Keep in mind that this forecast is still several
days out and the timing of the rain may change by Monday. By middle
week the forecast models are depicting a dirty ridge scenario
which will result in cool onshore flow and possibly a shower or
two through the end of the work week.
&&
Aviation...as of 11:10 PM PDT Wednesday...for 06z tafs. Some
clouds are showing up along the San Mateo coast near khaf and
around Monterey Bay under stiff onshore winds. Ceiling heights along
the coast are around 1500-2000 feet. Gusty west winds will slowly
ease overnight and not expecting ceilings inside the Bay but some
patchy clouds possible bumping up on the East Bay hills.
Vicinity of ksfo...VFR skies. Gusty west winds easing overnight then
increasing again Thursday afternoon.
Ksfo bridge approach...VFR. Similar to ksfo but lighter winds.
Monterey Bay area terminals...sct-bkn ceilings at 1500-2000 feet
overnight through 16z Thursday...then clearing. Gusty west winds
through the period.
&&
Mtr watches/warnings/advisories...
... Arena to pt Reyes 0-10 nm until 3 PM
Small Craft Advisory...pt Reyes to Pigeon pt 0-10 nm until 3 PM
Small Craft Advisory...Pigeon pt to pt pinos 0-10 nm until 3 PM
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm until 3 PM
Small Craft Advisory...pt Arena to Pigeon pt 10-60 nm until 3 PM
Small Craft Advisory...Pigeon pt to pt Piedras Blancas 10-60 nm until 3 PM
&&
$$
Public forecast: Larry
aviation/marine: rww
Visit US at www.Weather.Gov/sanfrancisco
Follow US on facebook, twitter, and youtube at:
www.Facebook.Com/US.Nationalweatherservice.Sanfranciscobayarea.Gov
www.Twitter.Com/nwsbayarea
www.Youtube.Com/nwsbayarea
