Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 200548

Area Forecast Discussion
National Weather Service Grand Junction CO
1148 PM MDT Thu Apr 19 2018

Issued at 902 PM MDT Thu Apr 19 2018

Falling temperatures and an influx of moisture have caused
relative humidity to recover above 15 percent. Meanwhile, winds
have decreased and therefore, extreme fire behavior is no longer a
threat and the Red Flag Warning will be allowed to expire.


.SHORT TERM...(Tonight through Friday night)
Issued at 356 PM MDT Thu Apr 19 2018

A strong late season winter storm is currently spinning over
southern Nevada and will continue to progress through the Great
Basin this evening. South-southwesterly flow has increased out
ahead of this system, resulting in increased cloud cover and wind
gusts of 30 to 40 MPH in some of the lower valleys. The current
Red Flag Warnings remain on track with the stronger gusts expected
to wind down overnight tonight. The focus will then shift from
fire weather to winter weather as the closed low progresses east
towards the Four Corners. Forecast models are still consistent in
having a nice tap of moisture streaming in from the south late
tonight which should kick off showers over the San Juan Mountains
before spreading further north overnight. The low will have
progressed into the Four Corners by daybreak Friday with
significant wraparound moisture allowing for numerous showers
along the Continental Divide. The low will be situated just east
of our forecast area Friday evening, transitioning our upper level
flow to the northeast and allowing for the northern and central
mountains to be more favored for heavier precipitation. The Winter
Weather Advisories and Winter Storm Warnings that were issued
earlier today remain on track. However, did make one change this
afternoon by upgrading the Gore and Elk Mountains to a Winter
Storm Warning to account for the increased forecast snowfall
amounts under the potential easterly and eventual northeasterly
flow, as well as the expected impacts to travel over Vail Pass on

The progression of this Pacific storm across our forecast area
will allow for most areas to see a decent chance for
precipitation, though the higher elevations will be favored for
activity. Regardless, plenty of clouds and cooler temperatures
can be expected across the region.

.LONG TERM...(Saturday through Thursday)
Issued at 356 PM MDT Thu Apr 19 2018

Northerly flow will set up early Saturday as the closed low
shifts towards the Colorado/Kansas border. Showers will gradually
diminish from west to east throughout the day on Saturday with
most activity ending by the evening hours. A transitory ridge of
high pressure will build overhead on Sunday, allowing skies to
clear and temperatures to rebound. The base of an upper level
trough looks to brush the far northern half of our forecast area
Monday afternoon and could bring some light isolated to scattered
orographic showers. Another closed low will develop over the
Pacific mid next week and track towards the CONUS but, at this
time, models are not in agreement in regards to the time of
arrival of this system on the west coast. Generally benign weather
should prevail through midweek with above seasonal temperatures.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1148 PM MDT Thu Apr 19 2018

Moisture will continue to stream northward into eastern Utah and
western Colorado over the next 24 hours. This will cause showers
to develop across the San Juans which will spread northward
through sunrise. Showers and low CIGS are likely to impact the
forecast for most TAF sites late tonight and during the day Friday
as this system moves through, especially at KHDN, KASE and KTEX.



CO...Winter Storm Warning until 6 AM MDT Saturday for COZ018-019.

     Winter Storm Warning until 6 AM MDT Saturday for COZ010-012.

     Winter Weather Advisory until 6 AM MDT Saturday for COZ004-013.

UT...Winter Weather Advisory from 6 AM Friday to 6 AM MDT Saturday
     for UTZ023.



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