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fxus66 ksto 122245 

Area forecast discussion
National Weather Service Sacramento California
245 PM PST Tue Nov 12 2019

dry weather pattern continues this week. Cooling trend this week,
but above normal high temperatures continue. Warmer this weekend.


biggest change from 24 hrs is the -10 and -11 deg temp change at rbl
and rdd, respectively at 20z. This is the result of light winds
compared to the warming katabatic winds of yesterday. With a strong
ridge over the region it is a mild day with Max temps mostly 8 to 15
deg above normal. SAC (78 in 1990), sck (78 in 1995), and moderate (80 in
1989) will be chasing/nearing record highs for the date, however,
most areas are seeing a degree or two of cooling from yesterday. The
probability of exceeding 77 deg at SAC is about 25% and 60+% at sck,
and less than 5% of exceeding 79 at moderate wrt bcconsraw. The British Columbia data
was used because we have been in a persistent pattern. Based on
these numbers, we would have to say that sck is likely to at least
tie, if not exceed, their Max temp record for the date, but the
other sites are very unlikely, especially at moderate.

Still looks as if we have a cooling trend for the rest of the week
(although Max temps will continue to run above normal), with a
warming trend for the weekend. A Pacific trof, with the low center
located near 30n/140w, is forecast to move inland Thu/Fri with
synoptic cooling and thickening clouds into Fri morning. The 700-500
relative humidity prog suggests the cloud cover will be thicker (more prevalent and
opaque) Wed nite into Fri morning, and during this time frame it
will generally be "cloudy" or "mostly cloudy", while generally
"partly cloudy" tonight through Wed due to "thinner" (generally more
transparent) cloudiness. This system will weaken drastically as it
moves into the strong ridge and may bring just a brief period of
locally breezy conditions to the NE SAC Vly fthls, and valley on
Sat. The average gusts are forecast in the low 20s miles per hour at rdd and
rbl on the European model (ecmwf) ensembles.

The 8-10 day 500 mb heights cluster suggests a trof will develop
over the Great Basin region which could bring some windy conditions
to our cwa, and much cooler wx and possibly a few light showers
mainly over the mtns. Jhm


Extended discussion (saturday through tuesday)...

Minimal changes were made in the afternoon forecast package as upper
level ridging will remain dominate in the extended period. This
will result in a drier and warmer weather returning with high
temperatures being around 5-15 degrees above normal for mid

Early next week, our persistent ridge will flatten a a bit as a
trough digs into the Pacific northwest. Deterministic models and
ensemble guidance differ on how this will impact US, with the most
consistent trend leading to a continuation of dry weather. An area
of concern with this trough passage will be with it's location.
Current thinking is that it'll be more to the east of US, which
would lead to breezy winds and low humidity values Tuesday into



VFR conditions the next 24 hours except local MVFR visibilities
from ksck southward 14z-18z Tuesday. Winds generally below 10 kts.

Sto watches/warnings/advisories...

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