Weather

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fxus65 kgjt 112147 
afdgjt 


Area forecast discussion 
National Weather Service Grand Junction Colorado 
346 PM MDT Sat Oct 11 2008 


..windy conditions with High Mountain snow expected to continue 
tonight... 


Short term...tonight through Monday... 
forecast area continued to get pummeled with rain and snow showers... 
thunderstorms and strong winds this afternoon. Many locations were 
receiving sustained winds ranging from 20 to 35 miles per hour with a number of 
locations reporting winds in excess of 50 miles per hour. Forecast soundings 
continued to suggest snow levels at or above 10000 feet in the 
southern mountains and have received no information which contradicts 
this analysis. Meanwhile...as models had predicted a dry slot swept 
northward across eastern Utah bring and end to most activity in the 
area this afternoon. 


The cold front was oriented north-south along the Green River in 
eastern Utah as of 1500 MDT. Models indicated that the front will 
rapidly push eastward across the County warning forecast area during the evening and will 
exit onto the plains by midnight as the low center lifts to the 
northeast. As a result...strong winds will continue late this 
afternoon and should decrease below below criteria early this 
evening. Meanwhile...snow...heavy at times will continue through the 
evening over the mountains of northeast Utah and western Colorado 
through midnight. As flow shifts around to the west behind the 
front...expect snow to continue over the northern mountains through 
morning. Colder air will filter in behind the system overnight... 
though wrap-around clouds will likely hold off freezing 
temperatures in the eastern Uinta Basin and the lower Yampa River 
Valley. 


Positive tilted trough will linger over the region with some wrap- 
around moisture continuing to bring showers to the northern zones 
on Sunday with dryer conditions Monday night and Tuesday. Clearing 
skies Sunday night will bring widespread freezing temperatures to 
the region and in all probability freeze warnings will be required. 
Daytime temperatures will be much cooler and generally split the 
difference between met and mav guidance. 


Long term...Monday night through Saturday... 
models in relatively good agreement through the period. This long 
term period should be starting out relatively dry...and Tuesday will 
begin a gradual warming trend for the week. Possible small fly in 
the ointment as models continue to develop a small closed low over 
Four Corners area late Monday from the lingering tail of the upper 
trough. Although models only drift this upper low very slowly 
eastward through early Tuesday...moisture should be limited and 700 mb 
flow likely to be down-sloping in easterly flow off the Continental 
Divide. A dry zonal flow will then prevail Tuesday night and on into 
Thursday...followed by a migratory upper ridge on Friday...and a 
strengthening southwest flow aloft on Friday night and Saturday as a 
potent looking Pacific trough moves inland on Saturday. Could be 
enough moisture spreading up in the southwest flow ahead of the 
trough on Saturday to produce a few showers mainly over the eastern 
Uinta Mountains and southern County Warning Area mountain zones by Saturday 
afternoon. 


&& 


Aviation... 
a cold front will blast through the region late this afternoon and 
into the evening bringing areas of MVFR and local IFR conditions to 
the mountains due to rain and snow showers as well as thunderstorms. 
Strong south winds ahead of the front will continue into the early 
evening generating widespread areas of mechanical turbulence over 
mountain areas...especially along the Continental Divide. Winds 
will shift to the west and weaken behind the front. VFR conditions 
will return to much of the region on Sunday...though localized MVFR 
ceilings and visibilities are likely in snow Sowers north of the I-70 
corridor. 


&& 


Gjt watches...warnings...advisories... 
Colorado...winter weather advisories in effect for areas above 10000 feet 
for the southwest and south-central mountains from noon today 
to midnight tonight...zones 09/12/18/19. 
Winter weather advisories in effect for areas above 9000 feet 
for the northern and central mountains from 3 PM today until 
6 am Sunday morning...zones 04/10/13. 
Wind Advisory until 6 PM MDT this evening for much of western 
Colorado...including zones 1/2/3/06/07/11/17/20/21/22/23. 
Utah...Winter Weather Advisory in effect for the eastern Uinta 
Mountains through this evening...zone 23. 
Wind Advisory for eastern Utah until 6 PM MDT this evening 
... Zones 22/24/27/28/29. 


$$ 


Short term.....Nl 
long term......jrp 
aviation.......nl