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fxus65 kgjt 232013 
afdgjt 


Area forecast discussion 
National Weather Service Grand Junction Colorado 
213 PM MDT Wednesday Jul 23 2008 


Short term...tonight through Friday... 
the monsoonal moisture plume was concentrated over the central Colorado 
mountains today with a weak vorticity maximum traveling along it. Best 
convection will continue developing over the Roan Plateau...piceance 
basin...Flat Tops and Routt County. These storms are developing under 
upper level deformation and bit of speed shear aloft. Further 
south...a subsidence inversion at about 19k mean sea level inhibited convection 
over the San Juan Mountains...but heating is now punching through that 
inversion to produce the expected numerous showers and 
thunderstorms...though relatively weak ones. 


As the moisture axis rotates clockwise through Thursday...northwest Colorado and 
NE Utah will continue to dry out...while central and southeast Colorado and southeast Utah 
will remain under the moisture plume...though this plume is slowly 
diminishing and areal coverage will decrease. Friday will get 
progressively drier from northwest to southeast and temperatures will remain seasonably 
warm. 


Long term...Friday night through Wednesday... 
through the weekend: latest models are a little juicier mainly 
during the earlier portion of the long term period. It looks like 
some of Dolly's moisture/energy will get entrained into the region. 
For this reason I have increased probability of precipitation...especially over the south... 
with heavy rain a possibility. But all zones should see at least a 
slight chance of thunderstorms. As a result of the abundant moisture 
expect some nighttime convection...with the south favored of course. 


Monday-wednesday: no big changes to the general monsoonal pattern 
with moisture remaining more plentiful over the southern portion. 
The latest run shows a little drying from the northwest during this 
period as the Theta-E ridge gets flattened. However...since the 
general pattern persists...have made few changes to the forecast. I 
did make sure that almost all zones have at least slight chance 
mention each afternoon and evening...with more plentiful probability of precipitation for 
the mountains and south. 


Temperatures will continue to be highly dependent on cloud cover and 
precipitation. 


&& 


Aviation... 
diurnally driven scattered thunderstorms will develop across the 
region. Storms will gradually diminish after sunset...but a 
few storms may persist through the night. Some thunderstorms will 
produce locally heavy rainfall...resulting in mountain obscuration 
and MVFR ceilings and visibilities. 


&& 


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


$$ 


Short term.....Cjc 
long term......eh 
aviation.......cjc/pf