Weather Service Report

FXUS66 KSTO 161615

915 AM PDT Wed Apr 16 2014

Breezy northerly winds developing today in the valley. A slight 
chance of showers over the mountains Thursday afternoon into Friday 
and possibly over the Northern Sacramento Valley Thursday evening. 
Temperatures above normal through Sunday then may cool to around 
normal early next week due to an unsettled weather pattern moving 
over the region.


.Short Term Discussion...
Ridge of high pressure over the area today with mostly sunny skies
and continued above normal temperatures. Locally Breezy and gusty
Northerly winds expected today with MFR-SAC surface pressure
gradient around 9 mb. Winds should decrease this afternoon and
turn southerly tonight with an approaching trough. Temperatures
this afternoon should warm up into the low to mid 80s in the
Valley and 60s to 70s in the mountains which is about 10 to 15
degrees above normal for mid April. 

The ridge of high pressure shifts to the east tonight and an upper
level trough approaches and then moves through Thursday afternoon
into Friday. This will bring cooler temperatures Thursday and
Friday with highs in the upper 70s to low 80s in the valley and
50s and 60s in the mountains. Precipitable waters increase to
around an inch Thursday afternoon into Friday indicating some
moisture with this system for a slight chance to chance of showers
over the mountains and possibly the Northern Sacramento Valley.
Snow levels are expected to be around 9000 ft. Precipitation
amount are generally expected to be less than a tenth of an inch.
Thunderstorms are possible along the Sierra...mainly south of
Highway 50 Friday afternoon and evening with energy rotating
around the low over Southern California.

Another trough may move onshore into the Pacific Northwest and possibly
brush by the far North on Saturday. Although the GFS keeps this
farther north and linger showers in the far SE corner of the CWA.
So there is some uncertainty in a slight chance of light
precipitation over the mountains for Saturday. Temperatures on
Saturday should be around 80 in the Valley and mid 50s to low 70s
in the mountains. 

.Extended Discussion (Sunday through Wednesday)

All models showing a large upper level low dropping southward
from the Gulf of Alaska towards the West Coast in the extended
forecast. Details of this system are not consistent across the
models, but a pattern change is expected. Sunday should remain
fairly dry and warm, but wetter and cooler conditions are expected
to arrive by Monday. The low could start bringing light
precipitation to Coastal & Northern mountains late Sunday. Showers
will then spread southward across our CWA Monday into Tuesday.
Valley highs will go from the low to mid 80s on Sunday cooling to
mid-upper 70s on Monday and upper 60s-low 70s by Tuesday.  JBB



Generally VFR conditions for valley TAF sites next 24 hours.
Northerly winds will be enhanced through 22z with sustained winds
10-20 kts and gusts up to 30 kts. Strongest winds will be along
the western side of the northern/central Sacramento Valley. Winds
become light again after 0z as VFR conditions continue.


.STO Watches/Warnings/Advisories...


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