...SHOWERS OVER NRN CA/NV SRN OR TODAY AS A FRONT MOVES THROUGH...
...LINGERING SHOWERS OVER THE SIERRA INTO NV THRS WITH DRYING INTO
THE WEEKEND...
...LARGER UPPER LOW TO BRING MORE WIDESPREAD PRECIP LATE
WEEKEND/EARLY NEXT WEEK...

.METEOROLOGICAL CONDITIONS (WED PM - TUE AM)...

Not much has changed since this morning. A front is beginning to
traverse nw CA sending some showers into srn OR, nrn CA, and nrn NV.
The front will continue to move through the rest of the day as the
upper low digs into the PacNW. The southwestern edge of the low will
descend into NV on Thursday allowing for some lingering showers
before a ridge builds in behind it returning dry conditions to the
region. Expecting another 0.10-0.50" over nw CA from that front.
Uncertainty is still quite high for the weekend or early next week
approaching upper low. Models continue to disagree on the arrival
timing and subsequent progression of the system. The 12z det ECMWF
has slowed down since this morning not heading inland as quickly on
Monday as in previous runs. The 12z det GFS remains the slowest of
the three models. Ensembles overall continue to show arrival timing
of showers anywhere between Saturday evening and Tuesday. The
official forecast still leans on the slower side compared to the
NBM. For the afternoon update, blended in the 12z GFS and ECMWF for
Sunday to keep precip more confined west of I-5 as both det models
agree on holding off the inland spread of precip until Monday. For
Monday, mainly used WPC/NBM but while pulling back the extent of
precip a bit to represent that slower timing. Confidence is low due
to the wide range of timing possibilities and lack of consensus
amongst the ensembles on a clear path. QPF for the weekend low: 1-2"
nrn CA west of Shasta (up to 2.50" or so Cape Mendocino), 0.50-1.25"
central coast mountains, and 0.25-0.75" most of the Bay Area
(locally higher across the North Bay)/nrn Sierra/central coast/Sac
Valley.