National Weather Service Forecast Discussion

			


000
fxus65 krev 020930
afdrev

area forecast discussion
national weather service reno nv
230 am pdt thu sep 2 2010

.short term...
high pressure aloft will bring warm weather with high temperatures
peaking at 5 to 10 degrees above average by friday. thermal trough
will struggle to make it east of the sierra crest today. this will
maintain one more day of light easterly surface winds. the thermal
trough will finally move east into the great basin by friday for a
return of afternoon westerlies. should see wind gusts to 20-25 mph
along the sierra and in the wrn nv valleys.

upper ridge is pushed east on saturday as another pacific trough
moves into the west coast. this will initiate a cooling trend that
will continue well into next week. increasing southwest flow aloft
in combination with favorable gradients will bring gusty winds to 30
mph or more during the afternoon and evening. 00z nam/gfs both show
widespread 30 agl winds near 25 kts by mid afternoon with surface rh
in the single digits to low teens. this could lead to critical fire
wx conditions. see fire weather section below for more details. scv

.long term...sunday through wednesday...
trough associated with upper low over british columbia will skim
northern nevada sunday and drive a front across the area. 00z models
have backed off a bit on winds for sunday afternoon...but position
of trough and upper jet remains favorable for gusty winds across the
area.

for early next week...models continue to show blocking pattern over
north america.  ridges over the gulf coast states and along 150w in
the central pacific...will maintain a trough west of the rockies
through most of next week.  this will open a north to south
storm track...with potential for cold systems from alaska and
western canada to reach the area.

00z models have maintained a deepening of the west coast tuesday and
wednesday...as a low drops out of canada.  despite some run to run
differences in the amount of cold air and track/strength of the low
models have been consistent with the timing of the feature.
increased pops tuesday night through wednesday...and lowered the
high temperature forecast several degrees below the statistical
guidance for the warm bias in anomalously cold systems.  brong

&&

.fire weather...
main fire weather concern is gusty winds and low humidity this
weekend.  trough to pass through the pacific northwest with the
upper jet over southern oregon saturday and sunday. this is a
favorable pattern for critical conditions with wind gusts of 30 mph
or more and low humidity.

there is uncertainty on which day will have the stronger winds.
yesterdays model solutions were favoring sunday with a front
reaching northern nevada sunday evening.  however some of the latest
runs have the stronger winds on saturday afternoon and saturday
night.

highest potential for critical conditions is along the sierra front
saturday due to increasing surface thermal and pressure
gradients...and across areas south of i-80 on sunday with the jet
and front passing through the area.  brong

&&

.aviation...
light winds and clear skies continue for all terminals with high
pressure over the sierra and western nevada through friday. brong

&&

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

$$

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