Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 091721
Area Forecast Discussion
National Weather Service Sacramento CA
921 AM PST TUE FEB 9 2016
DRY AND MILD WEATHER OVER INTERIOR NORCAL THIS WEEK.
Strong ridge/Omega Block`s axis has shifted just E of our CWA and
is oriented from B.C. into the Great Basin. The NAEFS climate
height percentiles and mean temp return intervals indicating a
30(+) year max of values has also shifted Ewd with the signals
suggesting the Srn portion of our CWA will have the best shot of
flirting with record max temps today. The lack of warming Nly
winds over the Nrn Sac Vly overnite...unlike last nite...has
resulted in cooler temps...and in RDD`s case a difference of
-22 from yesterday at 14z!
The probability of exceedance tool using the bias consensus of models
also reveals a similar finding and is included in parenthesis in the
record table below. The percentages show the probability of attaining
a record max today.
Record highs for today...
Redding Airport 78 set in 2006 (25%)
Red Bluff...... 78 set in 2006 (<5%)
Sacramento......73 set in 2006 (20%)
Sac Exec........72 set in 2006 (50%)
Stockton........71 set in 2006 (95%)
Modesto.........75 set in 2006 (15%)
After the early images from VIS Sat imagery...it appears the fog patch
around KMOD will not expand Nwd and will erode/mix out around 10 am or
Temperatures will begin to cool a bit across NorCal during the
mid to late week as the ridge weakens and its axis shifts slightly
to our east. In spite of the cooling...max temps will continue above
normal for the rest of the week. The NAEFS positive anomalies
weaken the for the rest of the week...but may return to the Srn
half of CA early next week.
Some patches of late night and early morning fog will continue to
form in the valley each night, mainly from around the Yuba City
Morning models and current satellite trends suggest that some cloud cover
from the system just offshore will survive encountering the ridge and spread
into the CWA late tonight and Wed. The clouds may thicken enough to produce
light precip/sprinkles over our Nrn Mtns Wed nite/Thu as a second wave
encounters the ridge. Will continue to look at this for the afternoon
.EXTENDED DISCUSSION (Saturday THROUGH Tuesday)
A faltering trough temporarily breaks down the ridge for a
fleeting chance of precipitation into Saturday across the north.
High pressure rebuilds Sunday into early next week with continued
warm and dry conditions, as well as a light offshore boundary
layer wind pattern. The broad ridge axis moves east of California
on Tuesday with southwest flow aloft and boundary layer onshore
winds. The GFS and ECMWF are still hinting at a more dynamic
frontal system impacting NorCal next Wednesday into Thursday.
Mainly VFR conditions the next 24 hours. Patchy ground fog this
morning in the Valley, and may redevelop Wednesday morning. Light
winds <10 kt will continue across Valley TAF sites.