872 
fxus65 kgjt 191103 
afdgjt 


Area forecast discussion 
National Weather Service Grand Junction Colorado 
400 am MST Wednesday Nov 19 2008 


Short term...today through Thursday night... 
the long wave pattern looks stable for the next week or more with a 
ridge over the intermountain west flanked by troughs in the eastern 
Pacific and East Coast. The malleable ridge will get a tad pummeled 
by shortwave energy starting Thursday night. 


Today-tonight: a dry cold front will work down the Front Range but 
have no affect on this side of the Continental Divide. The airmass 
will remain stable and dry. Some thickness packing works into the far 
north this afternoon for perhaps a few degrees of cooling. Otherwise 
temperatures will remain 10-15 degrees above normal. The Grand 
Junction record high of 65 degrees set just last year looks to be 
safe. Winds will remain mainly terrain driven. Strong surface-based 
inversions will set up before sunset. 


Thursday-Thursday night: the Aleutian low ejects an open trough 
across the northern Great Basin-rockies. The more-north GFS is 
favored...though the 06z run has come in slightly deeper. Southwest 
gradient winds will increase Thursday afternoon especially in the 
Utah and northern zones. Resisted the guidance temperature trend 
downward. Jet energy and associated cold front dig along the Colorado-Wyoming 
border Thursday night. But moisture looks limited for still no 
mention of showers even in the northern mountains. 


Long term...Friday through Tuesday... 
in the wake of a closed low across Montana and Wyoming...gradient 
northwest flow will be strong enough for the slight possibility of 
snow over the park and Gore Range. Cold advection in the middle levels 
is almost non existent and the air mass remains stable. The closed 
low would need to tract farther south for any accumulations...and 
that does not seem likely as the mean long wave ridge position holds. 


Progressive Flat ridge moves across the forecast area on 
Saturday...but a trailing short wave sweeps across northwestern Colorado on 
Sunday. The European model (ecmwf) is a little faster and keeps most of the energy 
to our north...meanwhile the GFS sweeps a trailing short wave over 
northwestern Colorado around Sunday evening. Either way...middle level cold 
advection appears minimal with limited moisture. For right 
now...will continue with the persistent dry forecast. 


Fo Monday and Tuesday...the GFS and European model (ecmwf) are in decent agreement 
that an amplified ridge axis will be over Utah and Colorado. Mostly 
clear conditions will continue with above normal temperatures. But 
instead of 60s...temperatures will have fallen back to the 50s for 
many valley areas. 


&& 


Aviation... 
VFR conditions continue today through Thursday. Some light to 
moderate turbulence will develop later Thursday as increasing stable 
southwest winds aloft create some mountain wave affects. 


&& 


Gjt watches/warnings/advisories... 
Colorado...none. 
Utah...none. 


$$ 


Short term.....Joe 
long term......pf 
aviation.......Joe