Area Forecast Discussion
Issued by NWS Sacramento, CA

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314
FXUS66 KSTO 262216
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
316 PM PDT Mon Jun 26 2017

.SYNOPSIS...
Near normal through midweek followed by a warming trend into the
weekend.

&&

.Discussion...
Short wave trof will be moving across our Nrn Mtn zones this
afternoon/early this evening with instability forecast over the
Trinity Alps/Siskiyous, just N of our CWA where isolated-scattered
convection is expected. Consensus from the higher resolution model
REF and QPF progs keep the convection outside of our CWA. Less
instability forecast on Tue even though weak troffing persists
over the region. This is the result of today`s short wave
providing stronger dynamics than Tue`s much weaker passing
disturbance. CAPE and modified Total Totals are much lower on Tue
than today. T-storm potential than nil for Wed/Thu in our CWA.

Break down of the ridge over the W Coast allows for a cooler air
mass over our CWA and temps this afternoon were running some 5-10
degrees cooler than yesterday over the Nrn and MTN zones and less
over the rest of the CWA. The greatest cooling today is away from
the Delta as the Delta area benefited from yesterday`s cooling.

Onshore gradients allowed some marine stratus to advect inland this
morning, but the marine stratus is becoming mixed out offshore
today. The aforementioned short wave will be moving farther inland
by Tue morning which should weaken the onshore flow. Although the
Delta Breeze will continue it should be generally weakening with
time into Tue. We are also skeptical that the marine layer will
deepen slightly as forecast by the NAM Bufkit from today. So, with
weaker onshore gradients and a marine layer that will not deepen
appreciably (if at all), any stratus that advects inland should
be rather patchy Tue morning.

Near normal temps expected next couple of days with a warm up to 2
to 7 degrees above normal for the mid and latter half of the week as
the West Coast ridge rebuilds.   JHM

.EXTENDED DISCUSSION (Friday THROUGH Monday)

Dry conditions are expected during the extended period, with
temperatures running about 5-7 degrees above normal through
Sunday. Model guidance suggests a series of short waves embedded
in the upper flow this weekend, leading to increased onshore
flow. Upper ridging will weaken as a trough builds into the
Pacific Northwest early next week. This should result in highs
near or slightly below normal.

&&

.AVIATION...

VFR conditions the next 24 hours. South to west winds 5 to 15 kt
across Valley TAF sites will decrease overnight. SW gusts up to
30 kt near the Delta. Patchy MVFR cigs possible in the vicinity of
KSAC and KMHR Tuesday morning.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$



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