Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Sacramento California
910 PM PDT Wed may 6 2015
low pressure dropping southward from the Pacific northwest will
bring a chance for showers and thunderstorms, mainly to the
mountains through the end of the week. Near normal temperatures
through the end of the week...then warming over the weekend. Breezy
north winds tonight and Thursday mainly on the west side of the
valley. Chance of showers or thunderstorms again early next week
mainly northern mountains.
Discussion (today through saturday)...
there are still some showers and isolated thunderstorms late this
evening but in general over the next few hours expect just some
isolated activity to occur. As the low shifts southward after
midnight and into Thursday morning that's when the models increase
the activity over the interior and mountains. This is also the
best time period for the valley to see any showers from this
The central part of the low drops down over the central
coast in the afternoon with models indicating showers likely over
the mountains and mainly dry conditions for the valley. Snow levels
may drop down to around 5000 feet Thursday morning but not much in
the way of snow is expected at that level or any for that matter
during this time period. Better accumulations will be above 7500
feet but a couple of inches down to around 6500 feet look possible
in the afternoon and evening and mainly from around Plumas County
southward. The higher total look to occur around Highway 88 and to
The low will continue to shift southward on Friday but wrap around
moisture from the low will continue chances for showers and
thunderstorms over the Sierra Nevada. Snow levels rise well above
pass levels to around 8000 feet or higher during the day.
By Saturday the low pressure will have moved well to the southeast
of the area. Models are trying to indicate some isolated afternoon
activity possible along the crest south of Tahoe...otherwise
expect dry conditions and slightly warmer temperatures.
Extended discussion (sunday through wednesday)
Medium range models showing weak upper ridging over the forecast
area Sunday with just a slight chance of afternoon showers or
thunderstorms over the coastal range and Shasta mountains. Another
upper low is then forecast to dig south along the northwest cal coast
Monday, swinging inland over interior norcal Tuesday. Models then
differ significantly on how quickly to eject the low eastward
Wednesday. Potential for showers and thunderstorms exist early
next week with Tuesday expected to be the most active day. Cooling
trend forecast with highs near normal by Tuesday.
Upr low digs S thru intr norcal nxt 24 hrs with mnly VFR conds exc
LCL MVFR poss in shwrs or tstms omtns. LCL nly sfc wnd gsts to 30 kts
dvlpg ovr intr norcal tngt into Thu mrng contg into Thu eve.
Winter Weather Advisory from 5 am Thursday to 5 am PDT Friday
West Slope northern Sierra Nevada.