Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 260905

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
305 AM MDT Fri May 26 2017

.SHORT TERM...(Today through Saturday)
Issued at 304 AM MDT Fri May 26 2017

Morning convection still rolling east to west across the forecast
area with some rain hitting the surface. The strong outflow winds
observed last evening have diminished with sfc dew points up,
pointing at these showers becoming a bit more efficient at driving
precip down to the ground. Expect morning showers to diminish with
a break in convection through midday as we await the arrival of
the next front/upper level system which is currently spinning
southeast across Idaho. Models in good agreement with this system
pushing through the area tonight and Saturday. Expect another up-
tick in showers as the front arrives with cooling aloft helping to
steepen up lapse rates again. This wave is a bit cooler and will
impact our northern mountains through Saturday evening. Could see
a few inches of wet snow, generally above the 9 to 10k mark by the
time this system departs. Temperatures will be running a bit
cooler today in most areas with continued cooling anticipated for
Saturday behind this newest front.

This forecast is not without some complications as we are seeing
rather dry conditions sweeping back into the lower valleys of
west-central Colorado, where fine vegetation has started drying
out. With winds gusting over 25 mph and humidity values expected
to drop back below 15 percent as drier air pushes in ahead of the
next front, we are anticipating a few hours of red flag
conditions. More on this in the fire weather discussion below.

.LONG TERM...(Saturday night through Thursday)
Issued at 304 AM MDT Fri May 26 2017

Rising heights across the Great Basin will drive the western U.S.
ridge eastward Saturday night and Sunday. This will swing drier
air across the southwest states up and over our forecast area,
resulting in decreased convective activity as we close out the
weekend. And Sunday showers will be diurnally driven and confined
to the higher terrain. This will also provide a boost in
temperatures with most areas climbing a good 4 to 6 degrees from
Saturday highs, although still trending on the cooler side of
normal for this time of year.

By Monday, the upper level ridge will be leaning a bit with axis
shifting to our northwest. This will allow some moisture to
return to the southern zones, although better push may wait until
Tuesday as we see energy undercut the ridge and eventually close
off a low to our southwest. Latest GFS run has marched away from
earlier runs, keeping energy more north across the southern Great
Basin versus the Baja California region. Whereas the ECMWF
continued to drive the low south. Both scenarios draw moisture
northward and bring a return of more active weather to our area
through the end of the week. Next up is the rather large ridge the
EC is trying to park over the western U.S. as we push into the
first week of June. This will bring much warmer weather to the
area beyond 8 days. Latest CPC guidance in line with this
potential. As far as precipitation is concerned, looks as though
moisture lingers around to keep diurnal showers and storms rolling
each afternoon and evening into the first week of June with
mountain locales likely the favored recipient.


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 304 AM MDT Fri May 26 2017

Westerly flow aloft will be in place today and will gradually
swing to the northwest tonight and Saturday as another cold front
drops south. This front will bring another round of showers and
isolated thunderstorms to the northern two-thirds of eastern Utah
and western Colorado with gusty outflow winds to 45 mph, brief
heavy precipitation and small hail all possible. Expect occasional
ILS cigs and brief MVFR cigs near showers, with these conditions
persisting through tonight. Away from the showers, expected VFR
conditions to prevail at all sites.


Issued at 304 AM MDT Fri May 26 2017

Breezy to windy conditions will develop across much of eastern
Utah and western Colorado this afternoon. The strongest winds are
expected to occur over west-central Colorado where critical fuels
are in place. As a result, a Red Flag Warning has been issued for
Colorado Fire Weather zones 203, 290 and 292. Portions of Colorado
Fire Weather zone 207 will all see brief periods of critical fire
weather conditions today, but long duration gusty winds are not
anticipated at this time. Isolated to scattered showers and
thunderstorms will also occur across the region today, with gusty
outflow winds to 45 mph, brief heavy precipitation and small hail
all possibly. The bulk of this activity will be north of a line
from Blanding, Utah to Gunnison, Colorado with areas along the
Wyoming state-line the most likely to see wetting rains.


CO...Red Flag Warning from noon today to 7 PM MDT this evening for



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