Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus66 ksto 201100 
afdsto

Area forecast discussion
National Weather Service Sacramento California
400 am PDT sun Oct 20 2019

Synopsis...
a slight chance of showers over the Shasta County mountains
today...otherwise dry through the extended period. Near normal
temperatures today then warmer than normal for the remainder of
this week. Breezy and dry conditions at times especially Wednesday
and Thursday when elevated fire weather concerns are expected.
&&

Discussion...
high pressure is currently building over the eastern Pacific and
West Coast. Most of the north state is under fair skies with some
mid clouds skimming over the northeast corner of the state. A
small scale disturbance dropping over the ridge might bring a few
showers over northern Shasta County today. Otherwise, the forecast
area will remain dry today with temperatures remaining a few to
several degrees below normal. High pressure continues to amplify
over the West Coast on Monday bringing a significant warm up on
Monday with daytime highs expected to bump up to several degrees
above normal. Surface high pressure pushes into the Pacific
northwest on Monday behind todays disturbance. This will bring
breezy north winds. This wind combined with the warming and
lowering relative humidity will bring elevated fire weather concerns although
duration and intensity of the stronger winds will be limited. High
pressure remains over the state on Tuesday bringing more warming
and continued dry conditions but overall wind should be a little
lighter. High pressure aloft amplifies more over the eastern
Pacific on Wednesday bringing more northerly flow aloft over the
West Coast. This combined with a tight northerly surface gradient
will bring increased north winds again especially down the west
side of the Sacramento Valley and over the Coast Range. The
increased wind and lowering humidity will bring a longer lasting
period of elevated fire weather concerns going in to the middle
part of the week.

&&

Extended discussion (thursday through sunday)...

Main concern in the extended period is the potential for critical
fire weather conditions mid to late next week as an upper level
trough drops down from western Canada into the Great Basin. As a
result, northerly to easterly pressure gradients will tighten,
resulting in strong offshore winds. This, in combination with dry
conditions and warm temperatures will likely bring critical fire
weather conditions. Lighter winds are expected on Friday as
pressure gradients relax. Temperature readings will reach into the
low and mid 80s in the valley late next week.

Ensemble guidance indicates another system diving into the region
next weekend. This could bring cooler temperatures, as well as
another round of gusty northerly winds. Will monitor the potential
for additional fire weather concerns during this timeframe.

&&

Aviation...

VFR conditions the next 24 hours at taf sites. Sustained winds
generally below 12 knots.

&&

National Weather Service Glossary of Abbreviations