Re: Area forecast discussion

Winter storm watch
Urgent - winter weather message...Updated
National weather service hanford ca
426 pm pst wed feb 23 2011

...Cold winter storm to impact central california...

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 by saturday.

Caz096-097-240830-
/o.Con.Khnx.Ws.A.0006.110225t0800z-110226t1800z/
Sierra nevada from yosemite to kings canyon-
Tulare county mountains-
426 pm pst wed feb 23 2011

...Winter storm watch remains in effect from late thursday night
Through saturday morning...

A winter storm watch remains in effect from late thursday night
Through saturday morning for the higher elevations of the
Southern sierra nevada.

* snow accumulations: 12 to 18 inches from 4000 to 7000 feet
And up to 3 feet above 7000 feet.

* timing: late thursday night through saturday morning.

* locations include: camp nelson...Giant forest...Johnsondale...
Lodgepole...Shaver lake...Huntington lake...Yosemite valley.

* winds: southwest winds 25 to 40 mph with gusts to 75 mph.

* impacts: snow covered roads...Treacherous driving conditions.
Possible road closures.

Precautionary/preparedness actions...

A winter storm watch means there is a potential for significant
Snow accumulations that may impact travel. Continue to monitor
The latest forecasts.

&&

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Area forecast discussion
National weather service san joaquin valley - hanford ca
303 pm pst wed feb 23 2011

.Synopsis...
Unsettled weather will return friday as a trough of low pressure digs southward into the area...With low snow levels into the weekend. Snow could fall in the foothills by friday night as the trough brings colder air into the region.


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.Discussion...Generally little change in temps compared to 24 hrs ago. Weak upper level disturbance rotating around upper level low off the coast of baja california has been bringing some clouds over the area. Expect the trough currently over the pac nw to begin digging southward on thursday...With the arctic front arriving in the northern cwa by late thursday night. This next system will be rather cold...Especially for late feb. Snow levels will generally fall to around 1000 feet throughout the central ca interior by fri aftn...Although they could be a little lower during fri night into sat.

As far as weather highlights are concerned...Will put out the winter storm watch for late thursday night into saturday morning for the southern sierra from yosemite to the tulare county mtns will even put out a winter storm watch for the mtns along the west side of the san joaquin valley and the sierra foothills at elev above 1500 feet from fri aftn thru sat am. Snow amounts will generally range from 2-6 inches from 1500 ft to around 3000 ft elev in both the west side and sierra foothills...And 6-12 inches above 3000 feet elevation in these area. Pass levels could see around 2-4
Inches in the kern county mtns.

As for the extended forecast...Or sun thru the middle of next week...Another storm system could impact the area tue into tue night...However it may only impact areas from fresno and northward. Confidence is low at this time concerning this system. Otherwise...Temps should moderate during sunday and early next week or warm closer to average for late feb/early march.

&&

.Aviation...Patchy late night/morning mvfr in hz/br in the san joaquin valley from 12-18z thursday and increasing obscuration southward over the sierra nevada in clouds and precipitation after 18z thursday...Otherwise vfr across the central ca interior through
00z friday.

&&

.Air quality issues...
None

&&

.Hnx watches/warnings/advisories...
Winter storm watch from late thursday night through saturday morning caz096-097.

Winter storm watch from friday afternoon through saturday morning above 1500 feet for the caz089-091-093>095.

&&

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Public...Bso
Avn/fw...Greiss
Synopsis...Tlm

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Area forecast discussion
National weather service san joaquin valley - hanford ca
1029 am pst thu feb 24 2011

.Synopsis...
Unsettled weather will return friday as a trough of low pressure digs southward into the area...With low snow levels into the weekend. Snow could fall in the foothills by friday night as the trough brings colder air into the region.


&&

.Discussion...
A stratocu deck is lingering over the south end of the valley and the adjoining foothills while higher level cloudiness is spreading southward across the region ahead of the cold storm system dropping south near the pac nw coast. Other than increased cloudiness...Expect conditions across the central california interior today to be similar to yesterday...Just a tad cooler under the cloudier skies. The approaching storm system is still on track to bring a significant change in conditions beginning tonight.

The winter storm warning for the sierra zones loooks on track and the current forecasted low snow levels look good also. A mix of snow within the rain showers in the valley can not be ruled out friday night into saturday morning as the cold air pushes in. Current winter storm watches for the foothills and tehachapi mountains will be evaluated for upgrade with the afternoon package.

&&

.Prev discussion... /issued 300 am pst thu feb 24 2011/

Discussion...
Temperatures across the central and southern san joaquin valley wednesday were in the mid 50s to mid 60s...Ranging from 57 at the madera and porterville municipal airports and merced regional airport...To 64 degrees at wasco. The latter also was the warmest spot in the hanford warning/forecast area.

The models continue to forecast a significant change in the weather pattern beginning this afternoon. An upper-level low over southern vancouver island early this morning is forecast to drop slowly south off the washington coast today...Reaching the oregon/washington line by 00z friday /1600 pst today/...And to off cape mendocino by 00z saturday /1600 pst friday/.

The upper-level trough will drop into northern california friday... Then continue to move slowly south friday night and into central california by 18z /1000 pst/ saturday.

Precipitation will reach the northern fringes of the hanford warning/forecast area by late this morning...Then over much of merced and mariposa counties this afternoon...Before spreading south overnight. Precipitation will spread across the entire central california interior friday through saturday. The 21z rfc qpf guidance through 00z sunday /1600 pst saturday/ calls for storm totals of 0.51 inch at fresno...1.85 inch at yosemite valley...And 1.44 inch at giant forest.

The main forecast concern is the very cold airmass that the models continue to forecast to move into the san joaquin valley friday night. By 12z /0400 pst/ saturday...925-mb temperatures fall to -1 c at least as far south as fresno county /per the 00z gfs/ or into kings and tulare counties / per the 06z nam-12/. The models have the coldest air over the valley between 12-18z /0400-1000 pst/ saturday with the nam-12 cooling925-mb temperatures over merced county to -3 c and bringing the -2 c isotherm almost as far south as the kings-kern county line. This cold airmass will drop snow levels friday night and saturday morning to at least 1000 feet...And possibly down to nearly 500 feet on the west side of the san joaquin valley where the models forecast the coldest airmass to be. It is possible that flurries early saturday morning could survive down to the valley floor for a dusting of snow.

In the southern sierra nevada...Will upgrade the winter storm watch to a winter storm warning from 08z friday /midnight tonight/ through 18z /1000 am/ saturday. Will keep the winter storm watch in place for the kern county mountains...The sierra nevada foothills...And the western foothills of the san joaquin valley as those areas will not see appreciable snow before friday...Which is the third forecast period.

The kern county deserts likely will see 1-3 inches of snow...Mainly friday night...And a winter weather advisory may need to be issued with either this afternoon/s or friday morning/s forecast package.

The storm is forecast to move east of the region saturday night...But the models are coming into better agreement on another storm reaching at least northern california by the middle of next week. Per collaboration with wfo/s monterey and sacramento...Have increased pops over the northern half of the hanford warning/ forecast area beginning next tuesday night for a wet start to march.

Dates of latest snows at bakersfield and fresno...


Dates of most recent snows at bakersfield and fresno...


&&

.Aviation...Vfr across the central ca interior through 00z fri. 00z fri - 18z friday...Areas of ifr in clouds/precip with mtn obscurations spreading south along the sierra nevada...And areas of mvfr -ra spreading south across the san joaquin valley. Desert areas will remain vfr through 18z friday.

&&

.Air quality issues...
None

&&

.Hnx watches/warnings/advisories...
Winter storm warning from midnight tonight to 10 am pst saturday caz096-097.

Winter storm watch from friday afternoon through saturday morning above 1500 feet for the caz089-091-093>095.

&&

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Public...Jeb
Avn/fw...Mendenhall
Synopsis...Pj

Discussion...Cold front is moving through central california this afternoon with areas of moderate to locally heavy precipitation ahead of it across madera and fresno county as of 3 pm...And moving southward. The cold upper low along the northern California coast will continue to drop south tonight bringing the colder air with it. Expect snow levels to lower rather fast this evening down to 1500 feet...And possibly below 1000 feet overnight. With this very cold air mass over the central and southern San Joaquin Valley tonight through Saturday...It is quite likely that a few flurries will be mixed with the rain and could reach the ground. Do not expect accumulating snow on the San Joaquin valley floor...Although isolated spots could see the ground covered. Winter weather warnings and advisories remain in effect.

The precipitation will be ending saturday evening...Except a few snow showers lingering in the kern county mountains continuing into early sunday morning. As the upper low exits the region...The next concern is cold temperatures Saturday night. Some cloud cover will likely remain through Saturday evening along the east side and south end of the San Joaquin Valley with some clearing overnight. The amount of cloud cover that remains will determine how cold the temperatures will be by sunday morning. Currently we are expecting enough clearing for temperatures to drop into the upper 20s to lower 30s with the coldest rural locations falling below 28 degrees for a few hours. A freeze watch has been issued for these cold temperatures. People with temperature sensitive plants and animals should be alert for the potential for freezing temperatures Saturday night and Sunday morning.

The weather will be dry sunday through tuesday morning...Then the next storm will reach the area beginning tuesday afternoon and continuing through Thursday. At this time...This appears to be a warmer storm as it is coming west across the Pacific instead of dropping in from the north.

Winter storm warning
Urgent - winter weather message
National weather service hanford ca
1112 am pst thu feb 24 2011

...Cold winter storm to impact central california...

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

Caz096-097-250000-
/o.Con.Khnx.Ws.W.0004.110225t0800z-110226t1800z/
Sierra nevada from yosemite to kings canyon-
Tulare county mountains-
1112 am pst thu feb 24 2011

...Winter storm warning remains in effect from midnight tonight
To 10 am pst saturday...

A winter storm warning remains in effect from midnight tonight to
10 am pst saturday for the southern sierra nevada.

* snow accumulations: 12 to 18 inches from 4000 to 7000 feet
And up to 3 feet above 7000 feet.

* timing: late tonight through saturday morning.

* locations include: camp nelson...Giant forest...Johnsondale...
Lodgepole...Shaver lake...Yosemite valley

* winds: southwest winds 25 to 40 mph with gusts to 75 mph.

* impacts: snow covered roads...Treacherous driving conditions.
Possible road closures.

Precautionary/preparedness actions...

A winter storm warning means significant amounts of snow are expected or occurring. Strong winds are also possible. This will make travel very hazardous or impossible.

&&

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