Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 170424
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
924 PM PDT Wed Apr 16 2014
A weak low pressure system will bring a slight chance of showers
over the mountains Thursday afternoon into Friday and over the
Northern Sacramento Valley by Thursday evening. Temperatures above
normal through Sunday then are forecast to cool to near normal to
below normal early next week due to an unsettled weather pattern
moving over the region. The best chance of showers over interior
Northern California looks like Monday night into Tuesday night
along with a slight chance of thunderstorms in the Valley Tuesday.
.Short Term Discussion...
A very weak weather system will skirt Northern California Thursday
afternoon into Friday. Conditions still look dry over the
interior through Thursday morning. Breezy flow through the delta
will to help cool interior temperatures a little for Thursday. The
shortwave will bring a slight chance of showers over the
mountains Thursday into Friday and over the northern half of the
Sacramento valley Thursday night. An isolated thunderstorm will
be possible as this system moves through but don`t expect that much
to form looking at the available moisture and instability.
For Friday the system will be moving into the Rockies with
lingering afternoon showers possible near the crest of the
Sierra Nevada. Cooler air filtering into the region should cool
interior valley temperatures into the upper 70s to lower 80s and
mountain temperatures into the mid 50s to upper 60s.
Saturday will be dry as another weak trough moves into the Pacific
Northwest only skirting the far northwest part of the state. The
flow will remain mostly zonal and temperatures are not expected to
change too much from Friday`s highs.
.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.
Have raised precip chances and introduced slight thunderstorm
chances Tuesday as forecast instability appears favorable. Valley
highs in the low 80s on Sunday cooling to mid-upper 70s on Monday
and upper 60s-low 70s by Tuesday.
General VFR conditions for valley TAF sites next 24 hours. Winds
will be northwest around 5-10 kt for the northern Sacramento
overnight, light elsewhere. Onshore winds expected by Thursday
afternoon, west-southwest winds locally gusting to 20 kt in the
Delta and remaining generally 10 kt or less elsewhere. Just some
thin high cloud overnight. EK