Weather

510 
fxus65 kgjt 071021 
afdgjt 


Area forecast discussion 
National Weather Service Grand Junction Colorado 
420 am MDT sun Sep 7 2008 


Short term...today through Monday night... 
another dry and stable day for the forecast area...but afternoon 
temperatures will be slightly higher as northwest flow retreats northward. 
A short wave moving over western Montana and northern Wyoming will sag 
southward and a shallow cold front sags into northwest Colorado Monday 
morning. A shot lived wind shift to north northeast may occur at 
Craig or Vernal...otherwise no significant weather change is 
expected as moisture stays east of The Divide. This front quickly 
dissipates Monday afternoon as a warm ridge replaces the departing 
short wave. 


Flow aloft veers to southwest Monday as a weak trough forms along 
the California coast. Moisture over southern Arizona will start 
spreading north Monday night. A few clouds may move over the southern 
half for milder nighttime conditions...but the air mass will stay 
stable. 


Long term...Tuesday through Saturday... 
models in fair agreement through the period with the latest GFS 
solution coming around to nearly match the ec. 


Short wave trough along the Southern California coast produces a southwest flow 
with the potential to bring some sub-tropical moisture northward 
into our County Warning Area. Latest NAM much slower than the current GFS...which 
has also backed off a little. Also current WV images and soundings 
indicate general lack of moisture over Mexico and southern Arizona. Still believe 
scattered probability of precipitation over the San Juans is a good choice...tapering off as one 
GOES north. Wednesday a decent short wave drops into the northern rockies 
providing some dynamic forcing over the north. Moisture still somewhat 
limited with only scattered mountain showers as a consequence. This 
circulation closes off near western Wyoming Thursday. This will increase lift 
over the north but unfortunately it looks like the dry slot will 
punch into the region limiting convective potential. 


Have generally followed the GFS which shows the southwest trough 
moving eastward during the weekend. Will keep the forecast on the 
dry side through Sat. 


Temperatures will generally be around normal with some cooling behind 
the cold front Friday. The cooling will be strongest over 
the north. Also clouds and precipitation will significantly influence 
temperatures at any given location. 


&& 


Aviation... 
VFR conditions will prevail through Monday. 


&& 


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


$$ 


Short term.....Pf 
long term......eh 
aviation.......cjc