Weather

020 
fxus65 kfgz 101904 
afdfgz 


Area forecast discussion 
National Weather Service Flagstaff Arizona 
1000 am MST Friday Oct 10 2008 


Synopsis...a strong storm system developing over the western Great 
Basin will bring continued very windy conditions to much of the 
region through Saturday. The windiest period will be late this 
evening into Saturday afternoon...when high winds in excess of 60 
miles per hour are possible. This storm will also bring sharply 
colder temperatures...with a chance of rain and snow especially east 
of Flagstaff. Cold temperatures will remain Sunday and Monday... 
before gradual improvement for the remainder of next week. 


&& 


Discussion...a strong and cold storm system was diving southward over 
Nevada and California this morning. This system is forecast to continue 
moving southward into southern Nevada tonight...then northeast into 
Utah and northern Arizona Saturday...bringing a major wind event to 
many areas. Some forecast updates have been sent for tonight... 
mainly to increase wind gusts. Rain chances were also increased for 
the area southeast of Payson to St Johns...as moisture is pulled northward 
ahead of the low. Otherwise...current forecasts are in good 
shape...and discussed in detail below. 


Previous discussion...(300 am MST Friday Oct 10)...the windiest times 
appear to be late tonight into Saturday afternoon. Models have been 
very consistent with strong 700mb winds of 50 to 70 knots across the 
Northland during this time frame. This will more than likely lead to 
a major wind event across much of the region and a high wind watch 
has been issued for all areas except for Yavapai and northern Gila 
County. Sustained winds of 35 to 45 miles per hour with gusts greater than 60 
miles per hour is entirely possible late Saturday morning and afternoon. People 
living in the high wind watch area should take necessary precautions 
now before the onset of this major wind event. 


As far as probability of precipitation go...there is still a possibility that significant 
moisture ahead of Hurricane Norbert could be tapped by this trough. 
The farther east of Flagstaff...the more likely a scenario this is. 
Our current grids have the highest probability of precipitation over the whites...with some 
cold-pool probability of precipitation northwest of Flagstaff Saturday afternoon. This looks 
good. The European has been the most aggressive with its quantitative precipitation forecast field 
higher and more west than the other solutions...although the NAM is 
now showing significant amounts over the whites and eastern rim. 
Have therefore adjusted quantitative precipitation forecast amounts higher over the aforementioned 
areas. It looks as if the snow levels will remain high over this 
area...around 9000 feet and higher...but would not be surprised to 
see the snow levels lowered another 500 feet or so due to 
evaporative cooling. 


The system will move north and east of the forecast area during the 
day on Sunday. This will help to bring the winds down to a more 
tolerable level. A return to drier weather is expected to return for 
the beginning of next week with temperatures around normal. 


&& 


Aviation...for the 18z package...a strong low pressure system will 
bring strong winds today and Saturday. Expect southwest winds of 25 
to 35 kts with gusts reaching 45 kts during the afternoon. Some 
moisture will move northward over far eastern Arizona with an 
increasing chance of showers with ceilings of 1-3 kft above ground level by 
Saturday morning. Elsewhere VFR conditions are anticipated. Aviation 
discussion not updated for amendments. 


&& 


Fgz watches/warnings/advisories... 


Wind Advisory from 7 am to 11 PM MST today for azz004>007- 
009>017-039-040. 


High wind watch from 11 PM this evening through Saturday evening for 
azz004>007-009>017-039-040. 


Wind Advisory from 7 am today to 9 PM MST Saturday for 
azz008-018-037-038. 


&& 


$$ 


Public.........Jj 
aviation.......mas 


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