Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 231049
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
349 AM PDT Sat May 23 2015
Warmer temperatures with showers and thunderstorms expected this
weekend into next week, especially over mountains.
.Discussion (Today through Tuesday)...
Broad upper low over desert SW this morning with a fairly
significant wave over the Pac NW moving southward. Leading edge
instability has triggered some showers over the west slopes of
Sierra northward of Hwy 20/I-80. The HRRR picked up on this area
of precipitation pretty well. The HRRR continues the
shower/thunderstorm development over the west slopes this
morning into the afternoon. The model also develops activity over
the Coastal Range from Glenn county down into western Yolo county
late this morning and afternoon.
In the meantime, marine stratus has developed over the Sacramento
region again this morning. As long as these troughs impact the
west coast, we keep the tightened onshore surface pressure
gradient and the threat of the stratus intrusion. Monday looks
like the next chance for some valley stratus.
The mountains will continue to see showery activity through
Tuesday, although activity may not be quite as widespread as
today. Seasonably cool temperatures will continue today with a
slow and gradual warming trend expected into early next week.
.Extended Discussion (Wednesday through Saturday)
Upper ridge forecast to return during the second half of next
week as the trough finally shifts east into the Rockies. This will
result in temperatures returning to around normal for late May
along with a reduction in mountain showers and thunderstorms.
Another trough may approach the west coast next weekend.
General VFR conditions expected next 24 hours except areas of
MVFR with local IFR conditions over the mountains in the vicinity
showers and isolated thunderstorms. Areas of MVFR ceilings in the
Sacramento area until about 16Z-17Z. Local southwesterly wind
gusts 10-20 kts.