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

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FXUS66 KMTR 200610

Area Forecast Discussion
National Weather Service San Francisco Bay Area
1010 PM PST Wed Feb 19 2020

.SYNOPSIS...High temperatures will warm through Friday with above
normal readings expected and dry conditions. A chance of
rain will return to the Central Coast Friday night into Saturday
but rainfall amounts will be light. Locations near and north of
San Francisco Bay will receive little to no rainfall. Dry
conditions will continue into next week.

&& of 08:27 PM PST Wednesday...We could definitely
use the rain(more on that later), but if you ventured outside
today it was rather pleasant for late February. Highs were mostly
in the 60s with a few interior spots creeping just over 70 degrees
- or several degrees above normal. The exceptions were in the
hills and immediate coast with highs staying in the 50s.

For tonight - an upper low developing well offshore will continue
to deepen and slowly drift southward. The low will help to usher
in some high clouds, which are already evident on the satellite
imagery. The increasing high clouds may keep temperatures a few
degrees warmer than Wednesday morning, but it will still be
chilly. Interior valleys sheltered from any wind will once again
drop into the 30s. Similar to Wednesday morning some patchy frost
will be possible across the interior valleys.

The upper low will continue to track southward Thursday into
Friday. This particular track will promote a general offshore
flow. Highs on Thursday and Friday will be mild thanks to the
offshore flow with 60s and 70s. By Friday the upper low off the
coast of Pt Conception will begin to move eastward. It appears
the low is try merge/phase into the sub-tropical jet and then get
kicked eastward quickly. The 00Z NAM/GFS are in and continue to
show some precip falling across portions of the Central Coast.
Sadly, the best upper level dynamics and limited moisture appear
to be south of the Bay Area. That being said, there is still a
chance for some precip to occur as far north as the Santa Cruz Mts
and East Bay Hills. There are timing differences in the models,
but current forecast will continue with Friday evening into
Saturday afternoon. Rainfall amounts are not impressive, but at
this rate we`ll take anything. The upper low finally exits to the
east on Saturday afternoon/evening taking any precip with it.

Rain chances thereafter are looking pretty bleak. Fantasy land
model guidance giveth and taketh away. The extended guidance did
show some rain chances in early March, but the latest guidance
rebuilds the ridge and keeps any storms north of the region.

&& of 10:10 PM PST Wednesday...For 06Z TAFs. An eddy
circulation similar to last night`s is redeveloping this evening
over the Monterey Bay. Low clouds forming over parts of the Monterey
Peninsula extend over to Moss Landing and over to Santa Cruz. KWVI
reports overcast IFR ceiling. Elsewhere it`s VFR, locally onshore
winds nearest the coast this evening otherwise shifting to light
offshore winds tonight and Thursday.

Vicinity of KSFO...VFR. W to WNW wind near 10 knots. Wind becoming
light NE later tonight and Thursday. West wind resuming Thursday

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR, though like last night it`ll be
borderline IFR ceilings KMRY and KSNS due to low clouds with an
eddy circulation. Winds light and variable this evening then SE 5
to 10 knot drainage winds may help mix out the low clouds or nudge
them westward back out over the bay. Variable to onshore winds will
likely redevelop by late Thursday afternoon.

&& of 9:45 PM PST Wednesday...A low pressure system
over the eastern Pacific will move southward tonight through
Thursday then by Friday will be located near Point Conception
before moving eastward over the weekend. The low will bring a
chance of showers to the southern coastal waters Friday into late
Friday night. Dry weather returns Sunday and Monday. A moderate
northwest swell persists through the week along with a light
southerly swell.





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