Weather

507 
fxus65 klkn 071037 cca 
afdlkn 


Area forecast discussion...corrected 
National Weather Service Elko Nevada 
334 am PDT sun Sep 7 2008 


Synopsis...high pressure will dominate the weather today and 
Monday with continued warm temperatures. A few thunderstorms will 
be possible Monday afternoon over White Pine County. An approaching 
cold front on Tuesday will bring a greater chance of thunderstorms... 
with breezy conditions. Temperatures will turn somewhat cooler for 
the remainder of the week. && 


Short term...today through Monday. Current satellite shows clear 
skies across the County Warning Area this morning with temperatures in the 40s... 
except near 60 in Tonopah and Wendover. At 500mb weak northwest flow has 
become zonal. Short-term models agree on weak zonal flow into 
Monday...becoming SW Monday afternoon as a trough and cold front 
approach from the west. Precipitable waters will continue on the dry side today... 
around 0.25 inches...moistening slightly to 0.30 to 0.35 inches 
Monday. Surface temperatures will rise an additional two degrees or 
so this afternoon...compared to yesterday...with similar highs on 
Monday. Middle-level moisture will begin to increase across the 
southern portion of the forecast area on Monday. This moisture...combined 
with marginally unstable lifted indice's...and low-level convergence may trigger 
a few dry thunderstorms in White Pine and northeast Nye counties 
Monday afternoon. Rea && 


Long term...Monday night through next Saturday. At the beginning of 
the longer term...a broad upper-level trough will be located over 
the western United States...with a weak ridge to the east and a much 
stronger ridge to the west over the eastern Pacific Ocean. With the 
flow turning more southerly on the eastern side of the trough... 
expect some monsoonal moisture to move northward by Tuesday afternoon 
and combine with instability associated with the trough. The result 
should be isolated showers and T-storms Tuesday afternoon and 
evening...mainly over the southeastern third of the County Warning Area including 
southeastern Elko County...most of White Pine County...southeastern 
Eureka County...and the eastern two thirds of northern Nye County. 
Otherwise...the big difference between Tuesday and previous days 
will be the wind...which should pick up noticeably ahead of an 
approaching front. 


Wednesday and Thursday...the broad trough is still sitting over the 
western United States...and a strong closed upper-level low and 
associated surface cold front is expected to be dropping southward 
right into the trough from the Canadian rockies on Wednesday. The 
closed low is then expected to linger in the area Thursday. This is 
a flip-flop of the GFS and European model (ecmwf)...which were keeping this feature 
further northeast in last nights runs. Thus...there is rather low 
confidence in the forecast from later Wednesday and beyond...but 
right now have continued a slight chance of thunderstorms across the 
eastern edge of the County Warning Area south of Wendover on Wednesday afternoon and 
evening...where lingering monsoonal moisture from earlier in the 
week will combine with instability associated with the trough. With 
winds aloft expected to have turned more westerly by 
Wednesday...think that the rest of the County Warning Area has a good bet at being 
dry as the monsoonal moisture is blown away and drier air advects 
in. However...with the closed low barreling southward into the County Warning Area 
by the end of Wednesday...I wouldn't be completely surprised if some 
showers developed near the Idaho border. By Thursday...the closed 
low is somewhere around the Utah-Idaho border. The GFS and European model (ecmwf) 
diverge here...with the European model (ecmwf) once again further west and south with 
the closed low...while the GFS moves it further north and east. The 
European model (ecmwf) solution would imply some instability showers are possible on 
Thursday with the low sitting directly over the County Warning Area...while the GFS 
would suggest it stays drier. For now have kept probability of precipitation below 15 
percent...but did nudge them upward from continuity. Given the 
likelihood of cool air moving in regardless of where exactly the 
closed low ends up...lowered temperatures several degrees especially 
in the north on both Wednesday and Thursday...and suspect they are 
not yet cool enough. 


On Friday and Saturday...both GFS and European model (ecmwf) move the closed low 
eastward away from US...and both build a modest ridge eastward into 
our County Warning Area. This should return our weather to its usual dry and 
sunny nature...and allow temperatures to start warming back up. Rcm 
&& 


Aviation...moisture and instability will increase across central 
Nevada today resulting in afternoon cumulus clouds...otherwise 
it will be dry. Winds should generally remain below 20 knots at all 
sites...with continued high visibilities. Rcm && 


Fire weather...high pressure will dominate the weather today and 
Monday with continued warm temperatures. A dry thunderstorm or two 
will be possible Monday afternoon over zone 455 and eastern zone 
457...as middle level moisture begins to increase across central Nevada. An 
approaching cold front on Tuesday will bring a greater coverage of 
afternoon and evening thunderstorms...mainly dry with lal 2 
coverage. 


Tuesday will be breezy ahead of the cold front with winds out of the 
southwest...and breezy again Wednesday behind the front with winds 
out of the west to northwest. The combination of gusty winds and low 
afternoon humidities could produce red flag conditions on either 
Tuesday or Wednesday. A Fire Weather Watch may be needed. 


Middle-level moisture may linger Wednesday in central Nevada as the 
trough associated with the cold front moves through...but slightly 
lower afternoon surface temperatures may limit instability. 


Afternoon temperatures will cool several degrees on Wednesday and 
Thursday. Rea && 


Lkn watches/warnings/advisories...none. 


$$