Weather

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Area forecast discussion 
National Weather Service Elko Nevada 
230 PM PDT Friday Aug 29 2008 


Synopsis...a strong storm system will move across the region during 
the next several days. Saturday will remain very warm to hot...but 
winds will become rather gusty...and isolated afternoon 
thunderstorms will develop in central and eastern Nevada. More 
scattered showers and thunderstorms will affect the area Sunday as 
much colder air rushes into the region...with rain and mountain snow 
showers expected Monday. && 


Short term...tonight through Sunday. As of this writing...the broad 
upper-level ridge axis is just passing from west to east across the 
County Warning Area...so its pretty much all downhill from here! However...tonight 
will feature dry weather and seasonable temperatures as some high 
clouds begin filtering into the area from the south. Tomorrow will 
be our last hot day for a while...but it will feel considerably 
different from today as strengthening winds ahead of the approaching 
trough result in gusts upwards of 35 miles per hour during the afternoon. 
Additionally...moisture pushing northwards ahead of the trough will 
cause isolated thunderstorms to develop across the southeastern half 
of the County Warning Area during the afternoon. It appears right now that 
thunderstorm development will be focused on the classic central 
Nevada convergence zone...stretching from northern Nye County into 
southern Eureka County and western White Pine County. 


Thunderstorms should diminish to showers later Saturday night...but 
these showers will likely linger all night as subtropical moisture 
continues pushing northward while some dynamics from the approaching 
trough come into play. Thunderstorms are expected to re-fire on 
Sunday...this time mainly across the eastern half of the County Warning Area with 
the highest chances of a storm being right along the Utah border. 
With plenty of upper-level divergence and jet stream energy 
associated with the approaching trough...along with the surface 
cold front which will be plowing across the state during the day... 
came very close to adding gusty wind/small hail wording to the 
grids...but decided to let it go one more shift. Right now there 
appears to be too much dry air for any thunderstorms across the 
western half of the County Warning Area...with the exception of parts of Humboldt 
County which will be near the core of the approaching trough. With 
the cold front passing across the region on Sunday...temperatures 
will cool noticeably...especially in Humboldt County where the front 
will arrive first. Winds will again be pretty strong with gusts 
expected to exceed 30 miles per hour in the north...and exceeding 40 miles per hour 
across the central Nevada Highlands. Winds will likely be 
especially strong and gusty right as the front passes... 
particularly on the southeastern and eastern slopes of the more 
prominent mountain ranges such as the rubies. It remains possible 
that a Wind Advisory will be required for Sunday afternoon. Rcm && 


Long term...Sunday night through Friday. Cold upper trough will 
move across northern and central Nevada Sunday night and Labor Day 
bringing a chance of showers...mainly east...along with much below 
normal temperatures for Labor Day with highs only in the 60s most 
locations. First frost of the season looks likely Tuesday morning at 
many locations. The rest of the week will see dry northwesterly flow over the 
area and a return to seasonal temperatures. Cec && 


Aviation...VFR conditions with light winds through tonight. Low 
pressure approaching the region on Saturday will bring increasing SW 
winds along with isolated thunderstorms to central and far eastern Nevada. 
Cec && 


Fire weather...quiet weather will persist tonight...but its most 
certainly the calm before the storm. Strong trough approaching from 
the northwest combined with an approaching surface cold front and its 
resultant pressure gradient will result in widespread wind gusts 
above 30 miles per hour during the afternoon tomorrow. With low level moisture 
remaining quite limited ahead of the front...decided to pull the 
trigger and upgrade our Fire Weather Watch to a red flag warning for 
all zones on Saturday afternoon. Strongest winds and best alignment 
appear to be across the north...with slightly higher humidity and 
weaker winds aloft in the south. However...with isolated mainly dry 
thunderstorms also expected to develop across the southern zones 
/particularly zones 455 and 457/...decided it was prudent to upgrade 
the entire watch. The red flag warning runs from noon to 9pm in the 
north...and from noon to 11pm across the south due to both the 
expectation of longer lasting winds and the threat of 
thunderstorms. While we've included an lal of 3 at present...it 
remains possible that lal levels reach level 6...so that even if 
the warning doesn't verify with wind/rh...it may well do so due to 
dry lightning. 


Things don't get much better on Sunday...when the cold front itself 
passes across the state. Isolated to scattered thunderstorms are 
expected Sunday afternoon across the eastern half of the County 
Warning Area...but these storms will probably transition to wet due 
to better dynamics aloft. These storms could also produce locally 
damaging winds and hail thanks to the potent storm system moving 
into the area. Winds will remain gusty elsewhere across the region... 
with gusts again near or above 30 miles per hour across much of the forecast 
area on Sunday afternoon. However...relative humidity should not be 
as low as on Saturday across the northern and eastern zones thanks 
to expected scattered thunderstorms /in the east/ and cooling behind 
the cold front /in the north/. However...relative humidity should 
again get quite low across the central zones 454 and 457...so have 
gone ahead and issued a Fire Weather Watch for Sunday afternoon. 
Emphasis in these zones is across the western halves of both zones... 
where no precipitation is expected at all on Sunday and winds may 
gust above 40 miles per hour. 


Fire weather conditions will improve Monday with cooler temperatures 
and higher humidity along with more scattered precipitation. 
Rcm && 


Lkn watches/warnings/advisories... 


Red flag warning in effect for all zones from noon Saturday 
through Saturday evening for gusty winds and low humidity. 


Fire Weather Watch in effect for zones 454 and 457 from noon 
Sunday through Sunday evening for gusty winds and low humidity. 


$$