172 
fxus65 kfgz 211055 
afdfgz 


Area forecast discussion 
National Weather Service Flagstaff Arizona 
345 am MST Friday Nov 21 2008 


Synopsis...dry and stable conditions will persist through the 
weekend. Expect mild daytime temperatures and light winds with high 
cirrus clouds moving across the Northland. Forecast models indicate 
a moist low pressure system will impact northern Arizona by Tuesday 
or Wednesday of next week...bringing rain...snow and cold 
temperatures through the Thanksgiving Holiday. 


&& 


Discussion... 
high clouds...dry conditions and mild afternoon temperatures will 
continue from today through Monday as westerly flow aloft persists 
over the Desert Southwest. 


The bigger story though is the pattern change forecast for the 
southwestern U.S. Starting Monday. The operational and ensemble 
models continue to show a cold trough of low pressure will approach 
the California coast Monday night. On Monday night... the 00z 
operational GFS is 12 to 18 hours faster in bringing a strong cold 
front across our state (now Tuesday and and Wednesday.) When compared to 
todays Canadian...ECMWF...and earlier GFS models runs. We are 
favoring the operational ec model for the Tuesday through Thursday 
forecast period...and have increased the chances for precipitation 
Wednesday through Thursday. The ec shows a progressive pattern with 
a cold frontal passage on Wednesday...and then the 500 mb trough axis 
crossing the state Thursday. Snow levels for Wednesday night are 
currently prognosticated to range from 8500 feet in the White Mountains to 
around 7000 feet on the Kaibab Plateau...and for Thursday from 8000 
feet in the White Mountains to around 6500 feet on the Kaibab Plateau. 




&& 


Aviation...for the 12z package...expect light winds...VFR 
conditions...and an occasional cirrus deck through the 24 hour 
forecast period. Aviation discussion not updated for amendments. 




&& 


Fgz watches/warnings/advisories...none. 


&& 


$$ 


Public.........Dl 
aviation.......kd 


Visit weather.Gov/Flagstaff for northern Arizona weather information.