National Weather Service Raw Text Product

Displaying AFOS PIL: AFDMTR Received: 2018-02-13 11:44 UTC

FXUS66 KMTR 131144

Area Forecast Discussion
National Weather Service San Francisco Bay Area
344 AM PST Tue Feb 13 2018

.SYNOPSIS...Continued dry with seasonable temperatures this week
followed by a warming trend Friday and Saturday. Some cooling
possible later in the weekend into early next week but the long
range forecast remains dry.

&& of 3:44 AM PST Tuesday...Skies are totally clear
this morning even with a well defined upper low over the Central
Coast. Clouds associated with this cold pool of air aloft are
impacting areas from San Luis Obispo county southward. The
circulation around the upper low has brought some offshore winds
to the Bay Area hills. Large scale gradients are about 7 mb
offshore with half a millibar from Sac and a 4.5 mb gradient down
the coast. Northeast wind gusts in the 25-40 mph range will
continue early this morning in the hills but the period of
strongest winds will peak around sunrise with easing winds by
lunch time. Otherwise today will be another pleasant Feb day with
sunny skies and afternoon highs into the 60s.

The upper low will eject inland by Weds with a ridge of high
pressure trying to nose over the Bay Area. MOS guidance suggests
temps may cool a few degrees as offshore flow is lost and there
could be some more cloud cover on Weds in advance of the next
upstream (dry) trough.

On Thursday another dry cold front passes through the state
keeping things dry over the Bay Area.  

Stronger high pressure then builds Friday and Saturday with a
noted warming trend when more upper 60s and 70s should become

Latest iteration of the mid/long range models has trended drier. 

The Sunday/Monday trough looks like it will stay to our north and
east as the dominant upper ridge over the East Pac wont back down.
Cooler temps associated with the trough may be felt by the end of
the holiday weekend but any precip looks to stay confined to our
north and east.

Some type of troughiness looks to stay in place next week but
nothing promising in terms of bringing some much needed winter


.AVIATION...As of 9:59 PM PST Monday...VFR. Offshore winds strengthen
tonight into Tuesday then weaken Tuesday afternoon and evening. Night-
time cooling and very localized stability will tend to decouple surface
winds from winds aloft thus low level wind shear (LLWS) is increasingly
probable specifically over the North Bay and East Bay low lying areas
and valleys this evening and lasting into Tuesday morning; KSTS and
KOAK tafs have LLWS indicated. Increasingly gusty NE-E winds are also
possible vicinity KHAF late tonight into Tuesday. Winds should be
lighter everywhere by late Tuesday afternoon and evening.

Vicinity of KSFO...VFR. Winds gradually shift to NE near 10 knots tonight,
possibly becoming northwest late Tuesday afternoon.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR. Light winds gradually shifting to E-SE
this evening and overnight. Winds becoming NW by late Tuesday afternoon.

&& of 03:31 AM PST Tuesday...Winds will decrease today
as a low pressure system over Nevada moves east. Winds will
increase again Wednesday night and Thursday as the next low
pressure system develops over the Great Basin from the northwest.





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