Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 231013
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
313 AM PDT Wed Jul 23 2014

.Synopsis...
After another below normal temperature day today expect a warming
trend Thursday into the weekend. The Sierra crest will see a
slight threat of thunderstorms early next week.

&&

.Short Term Discussion...An upper low pressure system off the
Pacific Northwest coast will swing inland today. Any precipitation
with this system will remain well north of the forecast area but
onshore flow around the bottom of the low will keep northern
California daytime temperatures below normal for one more day.
Fort Ord profiler showing the marine layer at around 3000 feet
this morning. In combination with a moderate delta breeze the deep
marine layer has allowed coastal stratus to push inland through
the delta and into the southern Sacramento valley so a few areas
will start the day with some low cloudiness. Most locations
however will see fair skies today under stable Southwest flow
aloft. Warming begins on Thursday as the upper low moves into the
northern Great Basin and the four corners high begins to shift
back westward. Surface high pressure nosing in over the Pacific
Northwest on Thursday morning will bring a moderate north wind
gradient for breezy north winds Thursday and Friday. These winds
will not be especially strong however due to no upper level
support. Daytime highs will come in around normal on Thursday then
warm more on Friday as upper level ridging amplifies over the west
coast. Airmass continues to warm on Saturday with daytime highs
expected to climb to just a bit above normal. Lighter pressure
gradients under the ridge will bring relatively light winds.


.Extended Discussion (Sunday through Wednesday)

Upper ridging will continue over the western U.S early next week
with the ridge axis over the Great Basin and southerly flow aloft
up the coast. This upper southerly flow will begin to bring
monsoon moisture back northward into the forecast area. GFS
precipitable water prog showing TPW over NORCAL Sunday at around
.8 inches or somewhat lower than TPW values during the latest
monsoon moisture surge. Still enough moisture however to warrant a
threat of crest thunderstorms over the Sierra south of Tahoe on
Sunday. Moisture pushes northward on Monday for a threat of
afternoon thunderstorms along the crest up to about the Lasson
area. Meanwhile the western U.S ridge begins to shift back
eastward a bit allowing for a slight cool down Monday. Little
change expected in the weather pattern Tuesday and Wednesday with
little movement in the Western U.S high forecast.

&&

.Aviation...

VFR conditions expected the next 24 hours. Near the Delta,
southwest winds 15 to 25 kt will be possible through Wed.


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$






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