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Area forecast discussion 
National Weather Service Las Vegas Nevada 
330 am PST Friday Nov 21 2008 


Synopsis...a pleasant weekend is in store for the region as 
temperatures will remain some 5 to 10 degrees above normal. 
A significant pattern change still looks likely during the middle to 
latter part of next week...with a chance for rain and mountain snow 
showers and temperatures falling below normal around Thanksgiving 
day. 


Short term...satellite shows a considerable area of high clouds 
lurking off the Southern California coast this morning. High clouds 
are associated with a weak southern stream disturbance. Disturbance 
will slowly shift east today and Saturday which will allow for 
high clouds to spread inland over the Mojave Desert today through 
Saturday. Less cloud cover should exist over the north. High clouds 
should dissipate or shift east Sunday as models indicate a ridge 
over the Great Basin. Here in Las Vegas we are on pace to establish 
the warmest November on record breaking last years record. 
Temperatures this weekend will not disappoint as readings will 
remain some 5 to 10 degrees above normal. 


Long term...a significant change in the weather pattern is expected 
by the middle of next week as a series of storms move into the area. 
It appears the 12z GFS/18z dgex from yesterday that were mentioned 
by the previous forecaster were outliers and are discounted as all 
available 00z model data now agrees with the pattern change. There 
is still a great deal of uncertainty in the timing and track of each 
storm and the amount of tropical moisture that is initially tapped 
but this could be the first significant widespread precipitation 
event in quite awhile. Models bring the first storm to the area 
Tuesday into Tuesday night bringing an increase in clouds and a 
chance of showers...mainly over the Sierra. With the over water 
trajectory of the system...temperatures on Tuesday should only be a 
few degrees cooler than Monday. Additional energy drops out of the 
Gulf of Alaska on Wednesday and reinforces the first system with 
additional cooler air. This should bring a more significant drop in 
temperatures...back to near normal...and a better chance of showers. 
Snow levels on Wednesday look like they could get as low as 7000 
feet or so. As the first storm tracks across and then east of the 
area on Thanksgiving day...another much colder system drops out of 
the Gulf of Alaska and into the Pacific northwest. This storm then moves 
into the area Friday bringing even colder air and additional chances 
for showers. Snow levels by this time could drop to or below 5000 
feet as the coldest air of the season arrives over the southwest. 
This all leads into what could be a chilly weekend for the last 
couple of days in November. 
&& 


Aviation...for McCarran...light diurnal winds expected through at 
least Saturday morning with variable high clouds at or above 25k feet. The 
long range outlook calls for a series of storms moving into the area 
by the middle of next week bringing abundant cloud cover and showers. 


For the rest of southern Nevada...northwest Arizona...and southeast 
California...overall light diurnal winds are expected across the 
area into early Saturday with variable amounts of high clouds at or above 
25k feet. The long range outlook calls for a series of storms moving 
into the area by the middle of next week bringing abundant cloud 
cover and showers. 
&& 


Vef watches/warnings/advisories... 
Nevada...none. 
Arizona...none. 
California...none. 
&& 


$$ 


Pierce/Salmen 


Http://weather.Gov/lasvegas