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Area forecast discussion 
National Weather Service Grand Junction Colorado
257 PM MDT Sat Aug 29 2015

Short term...(this evening through Sunday night)
issued at 256 PM MDT Sat Aug 29 2015

High pressure aloft centered near The Four Corners this afternoon.
Enough moisture still around over southern Colorado near decaying
frontal boundary to support isolated thunderstorms through the
evening over the San Juan Mountains...and possibly up toward Aspen
area. Otherwise expect a mostly clear overnight period. On
Sunday...the strong upper level trough over the Pacific northwest moves
inland and suppresses the upper level high south over nm. Slight
height falls and increasing upper level jet speeds...especially
over NE Utah will tug higher precipitable water air north over our
area. Should see a jump of at least a quarter inch. While not the
wettest we have seen this Summer it will still be enough along
with weak upper level forcing to result in better coverage of
showers and thunderstorms...and their threat will remain through
Sun night. Instability remains low and steering flow picks up flash flood threat will be low.

Long term...(monday through saturday)
issued at 256 PM MDT Sat Aug 29 2015

A cold front associated with low pressure moving across the northern
plains Monday will stall out/decay near the Wyoming border Monday.
There is some uncertainty about how much drying will occur south
of the front. Precipitation water values drop from Sunday...but still
around 0.50 inch north to 0.75 inch central and south. More upper
level jet energy moves overhead through Tuesday night so isolated
to scattered coverage of showers/thunderstorms will remain...favoring the
higher terrain...and probably more in Colorado than eastern Utah.
Southwest flow aloft will remain over the region through the
week...with the mean trough over the West Coast and high pressure
angled from nm to the upper MS valley region. Beyond
Wednesday...models suggest drier air moving in on the southwest
flow. As usual there are differences in the upper level pattern by
next weekend with the GFS more amplified with West Coast trough.
Will have lower chances of rain by the end of the week...but need
to maintain some mention over the mountains. Maximum/min temperatures
will change little day to day and be generally at or just above


Aviation...(for the 18z tafs through 18z Sunday afternoon)
issued at 1039 am MDT Sat Aug 29 2015

VFR conditions will prevail across eastern Utah and western Colorado for
the next 24 hours. From 19z to 02z isolated thunderstorms will form over the
San Juan mts from ktex east and over the central Colorado along the
Continental Divide around kccu...kase and northeast of kguc. Brief
showers and outflow wind gust to 35 miles per hour are possible with some of
these storms.


Gjt watches/warnings/advisories...


Short term...Ben
long term...Ben

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