National Weather Service Forecast Discussion

			


000
fxus65 krev 060404 cca
afdrev

area forecast discussion
national weather service reno nv
1256 pm pst sun feb 5 2012

.short term...
main feature for the short term is the splitting system tuesday
afternoon and models are at least in better agreement in regards
to it this afternoon. until then, ridge holds another day with
continued light winds and seasonable temperatures into monday.
mid and high cloud cover will gradually increase into monday night
ahead of the splitting storm.

by tuesday, the models are all in reasonable agreement with the
storm splitting and the southern end remaining just off the coast.
it will eventually form a cut-off low near baja by wednesday. this
system will have plenty of moisture and cloud cover will be
plentiful by tuesday afternoon. however, with the core of the
system remaining offshore and little if any forcing for the sierra
and western nevada i have hard time seeing much precipitation from
it.

i did increase pops near low end likely along the sierra crest
from tahoe south to mammoth. however, they rapidly drop off to the
east with barely a slight chance for the 395 corridor and nothing
into west central nevada. snow levels will be 5500-6000 feet for
the event so an inch or so of snow is possible near the sierra
crest. overnight lows will modify with less radiational cooling
due to cloud cover monday and tuesday nights. however, highs
tuesday will remain near normal as the cloud cover will also limit
any warming.

as the low passes south of the region wednesday, expect a
northeast low-mid level flow to develop. despite rising heights
and temperatures aloft, valleys will likely remain near normal due
to inversions. the mountains, however, will likely warm a few
degrees wednesday as h7 temps rise above freezing. wallmann

.long term...thursday through sunday...
little to no change was made to the extended grids with this
package.

the ho hum forecast continues as deep longwave troughing over the
north pacific and over eastern canada keeps a mean upper ridge over
the west. this will serve to dramatically weaken any energy trying
to punch inland over california and nevada. there are hints in the
10-day or so range that the eastern canadian trough may flush out
some to allow stronger energy to reach the west coast, but don`t
hold your breath quite yet.

as far as details, thursday and friday will feature a solid upper
ridge overhead for highs 5 to 10 degrees above average under mostly
sunny skies. saturday and sunday, the ridge weakens with the
potential for a couple weak disturbances to move through the west.
as mentioned before, nothing looks very impressive as the energy
gets split apart as it runs into the western conus ridge. the most
likely thing at this time looks to be increasing clouds and perhaps
a bit of cooling for next weekend.

on a side note, the 12z ecmwf came in with a fairly vigorous and
cold system for sunday. however, such a consolidated and vigorous
system does not make sense given the large scale pattern and other
guidance so i have thrown it out for now. the pattern shown in the
12z ecmwf may make more sense as we get towards the middle part of
next week if the longwave canadian trough can flush out and allow
more energy to move into the west. snyder
&&

.aviation...
vfr conditions and light winds with high pressure over the sierra
and western nevada through monday. low chance (10%) of fog at
ktrk/martis valley tonight with confidence too low to include in
the terminal forecast. brong/snyder
&&

.rev watches/warnings/advisories...
nv...none.
ca...none.
&&

$$

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