Scientific Forecaster Discussion

NWS Discussion
			
				

Area forecast discussion 
National Weather Service San Francisco Bay area 
859 PM PDT Wednesday may 22 2013 


Discussion...as of 9:00 PM PDT Wednesday...upper level low centered 
over the Pacific northwest brought cool temperatures to the 
district today. Highs today were a few degrees cooler than 
yesterday and 5-10 degrees below normal. 


The trough axis will move through the area Thursday then lift 
northeast on Friday. As a result temperatures Thursday will be 
the coolest of the week followed by a few degrees of warming on 
Friday. Another upper trough rotating around the low will move 
through the area over the weekend. The airmass wont be as cool as 
the current system so it wont be as cool but temperatures will 
continue to run below normal. 


The whole low pressure system will be out of the area by Monday 
and we should see a little more warming. Long range models 
indicate another upper low approaching the Pacific northwest by 
midweek. This system could bring light rain into northern 
California and there is a slight chance of some rain reaching the 
North Bay and coastal areas. 


&& 


Aviation...as of 4:55 PM PDT Wednesday...for 00z tafs. Cool upper 
trough and strong gradients will keep skies VFR overnight into Thursday. 
Only issue will be gusty west winds...strongest this evening but 
not as strong as 24 hours and with less impact on local operations. 
Airport weather warning for gusty west winds remains valid through 
04z at ksfo. 


Vicinity of ksfo...VFR skies. Gusty west winds sustained 20-25 knots 
with gusts around 35 knots...easing after 04z. Lighter west winds 
overnight into Thursday...then increasing again Thursday afternoon 
but lighter than today. 


Ksfo bridge approach...VFR. Similar to ksfo but lighter winds. 


Monterey Bay area terminals...VFR skies. Gusty west winds through 
04z then gradually easing overnight. Continued breezy Thursday 
afternoon but lighter than the last 2 days. 


&& 


Mtr watches/warnings/advisories... 
... Arena to pt Reyes 0-10 nm 
Small Craft Advisory...pt Reyes to Pigeon pt 0-10 nm 
Small Craft Advisory...Pigeon pt to pt pinos 0-10 nm 
Small Craft Advisory...pt Arena to Pigeon pt 10-60 nm 
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm from 9 PM 
Small Craft Advisory...Pigeon pt to pt Piedras Blancas 10-60 nm from 9 PM 
glw...pt pinos to pt Piedras Blancas 0-10 nm until 9 PM 
glw...Pigeon pt to pt Piedras Blancas 10-60 nm until 9 PM 
Small Craft Advisory...sf Bay until midnight 
Small Craft Advisory...mry Bay until midnight 


&& 


$$ 


Public forecast: west pi 
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