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Area forecast discussion 
National Weather Service Cheyenne Wyoming
206 PM MDT Monday Oct 20 2014

Short term...(this evening through Tuesday night)
issued at 206 PM MDT Monday Oct 20 2014

Another quiet and mild day across the County Warning Area today but some subtle
changes indicated with some cumulus over the southern mountains on the nose
of a push of moisture from the south. This will continue through
Tuesday ahead of a decent upper trough that will move onshore over
the Pacific northwest overnight. This system will then move across the
northern rockys Tuesday into the northern High Plains Tuesday
night...just providing a glancing shot of energy to the County Warning Area
Tuesday afternoon and night. Should be enough moisture around to set
off at least widely scattered showers to parts of the County Warning Area Tuesday
afternoon and evening...with even a few weak storms possible
around the mountains Tuesday afternoon where some modest instability
should exist. A weak Pacific front will then swing by later
Tuesday night as the upper shortwave lifts over the northern High

Long term...(wednesday through monday)
issued at 206 PM MDT Monday Oct 20 2014

Models in decent synoptic agreement at 500 mb...leading
to moderate to high confidence in their respective solutions through
Saturday...then the 20/12z GFS and European model (ecmwf) diverge...with the GFS more
progressive with the shortwave trough over The Rockies on Sunday. On
Monday...the GFS forecasts northwest flow aloft over our
counties...while the European model (ecmwf) depicts a pseudo cutoff upper trough over
The Four Corners...leading to more limited confidence in model
solutions for days 5 through 7.

Wednesday...shortwave trough feature aloft moves from eastern
Montana in the morning into North Dakota...with associated
clouds...precipitation and winds diminishing and decreasing across
our counties.

Thursday...decent autumnal warming trend on tap with west flow
aloft...inducing surface Lee troughing and in turn boosting maximum
temperatures into the 60s and 70s at lower elevations under limited
cloud covered skies.

Friday...balmy way to end the traditional workweek with large scale
ridging centered over New Mexico and unusually high 500 mb heights
over our counties...582 dekameters. With prognosticated 700 mb temperatures
near 10 celsius...expect maximum temperatures well into the 60s and
70s...even some upper 70s with downslope warming and Bone dry

Saturday...our flow aloft becomes southwest as the ridge aloft moves
to our east...thus this day may actually be the warmest of the next
week as surface Lee troughing adds even more warming due to
downsloping south and southwest winds and a Bone dry airmass.

Sunday...20/12z GFS and European model (ecmwf) solutions diverge...thus lesser
confidence in which solution will verify...though the European model (ecmwf) has
tended to do better in the past few fall and winter seasons.
Definitely cooler temperatures with a weak Pacific cold frontal
passage early in the day and will blend with our neighboring
offices...keeping isolated to scattered probability of precipitation west of a Douglas to
Laramie believe the GFS may be too bullish with quantitative precipitation forecast in the
afternoon and prefer the drier European model (ecmwf) solution with the upper trough
hanging back over Utah.

Monday...continuing on with preference to the European model (ecmwf) solution...the
upper trough will be mostly cutoff over The Four Corners with the
bulk of the precipitation over Colorado. Will hang onto some low
chance probability of precipitation for our counties to blend with our neighboring
offices...though mostly dry is usually the way to go this time of
year considering climatology.


Aviation...(for the 18z tafs through 18z Tuesday morning)
issued at 1111 am MDT Monday Oct 20 2014

VFR expected across the area through Tuesday with high pressure
residing over Colorado and Wyoming.


Fire weather...
issued at 206 PM MDT Monday Oct 20 2014

No significant concerns seen for the week with weather factors
remaining mostly non-critical. Some gusty winds will occur over
far western areas Tuesday afternoon.


Cys watches/warnings/advisories...


long term...Rubin

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