...ISOLATED SHOWERS AND T-STORMS OVER THE NRN/CNTRL SIERRA TODAY
WITH DRY CONDITIONS ELSEWHERE...
...SCATTERED SHOWERS AND T-STORMS OVER THE WEEKEND FOR NRN/CNTRL CA,
MAINLY EAST OF I-5...

.METEOROLOGICAL CONDITIONS (FRI AM - THU AM)...

Troughing is developing offshore of CA this morning as a large upper
low sits over central Canada encompassing much of the Intermountain
West. Current radar shows some light returns near the central coast
that may drop a few sprinkles the next couple of hours. Otherwise,
generally dry conditions across the region today with the exception
of some instability over the nrn/cntrl Sierra this afternoon that
may result in thunderstorms. The developing offshore trough will
continue to strengthen into Saturday before moving overhead later
into the weekend. This is expected to generate scattered showers and
thunderstorms over nrn/cntrl CA, mainly east of I-5. A few showers
also possible for coastal srn CA. That first trough looks to exit
into the Four Corners late Sunday as another descends from the PacNW
keeping scattered showers and thunderstorms in the forecast for
those same areas. Light precip will hang on into Tuesday before dry
conditions return as that second trough moves off.

Models then have another offshore low approaching mid week, but
disagree on the general pattern and movement of that system. The GFS
has a more organized upper low heading into srn CA Wednesday night
then joined by a more compact low dropping into NV from OR/ID. This
would generate additional scattered showers across much of the
region. The ECMWF has a more open trough further to the south going
through far srn CA and Baja early Weds evening before a ridge moves
in overhead at the end of the current window. This would still
produce some showers though mainly for southern CA. In either case,
amounts look fairly minimal. Ensemble 24 hr QPF up and down the
coast is under 0.50" for all members.

In addition to showers and thunderstorms, all this troughing will
keep afternoon high temperatures below normal. Anomalies reaching a
minimum over the weekend of -5 to -15 deg F before temperatures
gradually rise throughout next week.

QPF was mainly a blend of WPC guidance and the NBM. Majority of the
precip is expected for this weekend with around 0.10" or less for
the extended (locally up to 0.25" eastern NV). For the weekend
systems: 0.50-1.25" Shasta, 0.10-0.75" Sierra and cntrl/srn NV, and
0.10-0.30" for coastal srn CA with locally higher/lower amounts.
Freezing levels lowering from 9-12 kft today down to 7-10 kft on
Saturday bottoming out at 6-7.5 kft for most of the region by early
Sunday. Levels to then gradually rise the rest of the weekend and
early next week back up to 8.5-11 kft by late Tuesday.

Please Note: This product may NOT be routinely updated.
Please refer to the following product issued by the CNRFC
www.cnrfc.noaa.gov/Daily-Briefing for a graphical summary of
weather and hydrologic conditions.