Hazardous weather outlook

Hazardous weather outlook
National weather service san joaquin valley - hanford ca
435 am pst mon feb 21 2011

Caz089>099-221245-
West central san joaquin valley-east central san joaquin valley-
Southwestern san joaquin valley-southeastern san joaquin valley-
Mariposa madera and fresno county foothills-
Tulare county foothills-kern county mountains-
Sierra nevada from yosemite to kings canyon-
Tulare county mountains-indian wells valley-
Southeastern kern county desert-
435 am pst mon feb 21 2011

...Cold and wet by weeks end...

This hazardous weather outlook is for all of interior central
California.

.Day one...Today and tonight

Hazardous weather is not expected.

.Days two through seven...Tuesday through sunday

A cold low pressure area is forecast to develop off of the pacific
Northwest coast by thursday. This low will move south...And be
Across central california saturday.

Periods of mainly light rain and mountain snow is expected to
Begin sometime thursday or thursday night...And continue through
Friday. As the upper low moves across central california
Saturday...Precipitation will become more showery in nature. While
It is still too early to say how much rain and snow will fall...It
Does not appear to be a major storm...But it will be a cold one.

Snow levels could drop to 1000 to 2000 feet at times...Possibly
Even less than 1000 feet late friday night or saturday.

If you have outdoor or travel plans later this week...Be sure to
Monitor the latest forecast.

.Spotter information statement...

Skywarn spotter activation will not be needed.

Weather spotters are encouraged to report any significant or
Unusual conditions to the national weather service.

$$

Bingham

The next system to impact the region will originate from western canada and have some arctic air associated with it. The models have slowed the timing of the system around 12 hours and the gfs is drier with the qpf than the ecmwf. A very cold upper level low pressure center will slowly slide south along the west coast thursday and friday. The front moves into the nrn portion of the region by friday with precip spreading south through the day on friday. The bulk of the cold air will move into the central ca interior friday night and into saturday as the precip ends early sunday.

The snow levels will drop well into the sierra nevada foothills fri night and sat as the upper low moves through. Snow levels should also be low enough to impact travel through the tehachapi mountain passes as well. Snow amounts are expected to be lighter across the tehachapi mountains compared to the sierra based on the trajectory of the system. One interesting point is that the cold air will fluff up the snow with snow ratios around 15 to 20 inches per one inch of liquid across the sierra.

Confidence remains low to moderate right now based on timing differences and qpf amounts...Thus have held off on a watch for now for the sierra. Will continue outlook information and see if we can get a better handle on the timing and qpf amounts in future model runs.

The low center is expected to move out late in the weekend and a weak ridge builds in over the region by monday and continue through next tuesday with a slight warming trend and continued mostly clear conditions.