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fxus65 kvef 231707 
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Area forecast discussion 
National Weather Service Las Vegas Nevada 
907 am PST Monday Nov 23 2009 


Synopsis...an area of high pressure over the eastern Pacific will 
gradually shift east and be over the Great Basin by Wednesday. Some 
high clouds will drift overhead from time to time while gusty north 
winds will occur down the Colorado River valley. Temperatures will 
be near normal through Wednesday but will warm several degrees 
Thursday and Friday. 
&& 


Update...main concern today is north winds down the Colorado River. 
Through 9 am...all observations are below lake Wind Advisory 
criteria...but not by much. Will keep an eye on this. Rest of 
package looks good...and no update planned at this time. 
&& 


Aviation...for McCarran...high pressure building north of the area 
will result in a persistent northeast winds as the north/south 
pressure gradient increases through the morning. Gusts into the middle 
twenties will likely occur at times this morning and through the 
late afternoon before subsiding but sill out of the northeast. 
Tonight winds will be light form the northwest to north and then 
northeast Tuesday afternoon in the 10 to 15 knot range. Skies will 
be clear to varying amounts of high clouds. 


For the rest of southern Nevada...northwest Arizona...and southeast 
California...northerly winds will be the rule today as high pressure 
builds north of the region. On average...winds gusts will likely 
range from 15-25 knots through the day...but will be stronger in the 
Colorado River valley where gusts to near 30 knots are possible. 
&& 


Previous discussion... 
345 am PST Monday Nov 23 2009 


Short term...dry northwest flow aloft will be over the area today 
and Tuesday with a ridge of high pressure just off the coast. Some 
high clouds will drift through in the northwest flow while a 
tightening northerly surface gradient will bring locally breezy 
conditions down the Colorado River. Kept wind speeds generally below 
lake Wind Advisory criteria but nam12 MOS guidance indicates the 
winds at Needles and Bullhead City will at least briefly meet that 
criteria. Of course the GFS guidance is much lighter. So..day shift 
will need to monitor. The upper ridge will move over the area 
Wednesday with continued dry conditions and the beginning of a 
warming trend. Overall though...temperatures will be pretty close to 
normal through Wednesday. 


Long term...for the period beginning Thursday morning...ridging 
will keep the area under clear skies and above normal temperatures 
on Thanksgiving day...but a low pressure system will impact the area 
late Friday and through the weekend...which will result in decreased 
temperatures and breezy to windy conditions all day Saturday and 
into Sunday. Details are hard to come by...as models continue to 
show poor agreement...but overall consensus definitely leans towards 
a low pressure impacting the region...with limited moisture...so 
have kept probability of precipitation too low for any mention of precipitation in the extended 
forecast. High pressure will then build back over the region through 
the first half of next week. 


Aviation...for McCarran...high pressure building north of the area 
will result in a persistent northeasterly wind as the north/south 
pressure gradient increases through the morning. Gusts into the 
upper teens will likely occur at times late this morning and through 
the afternoon...but too infrequently to include in the 12z tafs. 
Afternoon winds will likely remain out of the northeast through 
Wednesday. 


For the rest of southern Nevada...northwest Arizona...and southeast 
California...northerly winds will be the rule today as high pressure 
builds north of the region. On average...winds gusts will likely 
range from 15-25 knots through the day...but may be stronger along 
the Colorado River valley. 
&& 


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


$$ 


Morgan/Jacques/Harrison/Kennedy 


Http://weather.Gov/lasvegas