Weather

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fxus65 kgjt 212030 
afdgjt 


Area forecast discussion 
National Weather Service Grand Junction Colorado 
230 PM MDT Thursday Aug 21 2008 


Short term...tonight through Saturday... 
dry westerly flow and capped out atmosphere has resulted in a quiet 
day across western Colorado and eastern Utah. Little change through 
tonight with clear and seasonal conditions expected tonight. 


On Friday...weak surface front slides southeast into southern 
Wyoming and then slowly creeps across our northern zones Friday 
afternoon...becoming stationary just north of the tavaputs. 
Moisture pooling along and just behind the front...combined with 
slight cooling aloft...will bring increasingly unstable 
conditions to the northern zones by late afternoon. Will 
continue to carry isolated probability of precipitation...mainly over the mountains 
north of Interstate 70 for Friday afternoon and evening. Cloud 
cover and increased relative humidity will be enough to shave a degree or two off 
maximum temperatures Friday over the far northern zones...otherwise persistence 
the key with maximum temperatures. 


Friday night and Saturday...heights rise over The Four Corners 
region...with high pressure building in. Moisture cycles through the 
ridge to bring an increasing chance for diurnally driven showers 
and thunderstorms...especially over the higher terrain. Increased 
moisture and cloud cover will hold min temperatures up a few degrees 
Friday night...with maximum temperatures on Saturday dropping a couple 
degrees across the board. 


Long term...Saturday night through Thursday... 


Made little change to the current forecast grids for this period. 
Upper level ridge should remain the dominant weather feature over the 
southwest through Monday. Still some hint at moisture working up 
underneath the ridge into SW Colorado sun-Mon...but that signal has been 
weakening over the last few days. Models keep the main storm track 
across the northern tier states next week...with a trough passing 
about next Wednesday. Some model and run-to-run inconsistencies lowers 
confidence. For now...a generally westerly flow should keep any 
southern moisture at Bay while best dynamics remain to the north. 
Thus...will continue with the current mostly dry forecast in place 
Tuesday-Thursday until a clearer picture emerges. Temperatures generally above 
normal. 


&& 


Aviation... 
isolated high-based diurnal thunderstorms possible over the mountains 
through Saturday...then increasing some in aerial coverage Sunday 
and Monday. Otherwise...VFR conditions to prevail over the area 
through Friday as a generally dry westerly flow will persist. 


&& 


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


$$ 


Short term.....Jdc 
long term......jad 
aviation.......jdc