Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 191026

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
326 AM MST Sun Nov 19 2017

.SHORT TERM...(Today through Monday)
Issued at 326 AM MST Sun Nov 19 2017

A quiet and cold night in place with some high clouds drifting
through associated with a weak system well to our north. GOES16
imagery suggest some fog developing off the warmer waters of Blue
Mesa as are temperatures hover near the single digits. CDOT
webcams do not show fog impacting the area yet but the camera
density is low and of course it is dark. Will monitor this through
sunrise. Otherwise temperatures will be the main challenge in the
short term forecast as warmer temperatures arrive aloft to
strengthen valley inversions. Lowered temperatures across the
north and Gunny Valley today and most areas tonight with very dry
air still in place. A clipper type system digs down the high
prairies of central Canada causing the western ridge to sharpen
along the left coast. This gives us a more direct feed of high
level moisture and clouds will be thickening across the north late

.LONG TERM...(Monday night through Saturday)
Issued at 326 AM MST Sun Nov 19 2017

The persistent ridge of high pressure mentioned earlier will
flatten somewhat Monday as a shortwave disturbance grazes the
northern edge of the area. The ridge will strengthen considerably
Tuesday and Wednesday. Both the ECMWF and GFS show a mid level
593dm high developing over Baja and the Sea of Cortez through
Thursday morning. This classic style blocking high should keep the
area in west northwesterly flow aloft through the entirety of
next week. 700mb temperatures show a considerable warm up through
the week with values near 9c creeping into southern Colorado and
Utah by weeks end. This suggests a strong warm trend through the
week, with sfc temperatures running 5 to 10 degrees above normal
by midweek. This makes sense given the warm advection regime and
mostly sunny skies under the ridge aloft.

By next weekend, models begin to diverge on the placement of the mid
level high and a series of shortwave troughs moving around it. The
ECMWF is flatter and more broad with the high. THis allows a quick
moving shortwave to graze the northern half of the area,
potentially bringing some precip with it. The GFS is still
amplified with the ridge axis over the Four Corners, keeping us high
and dry well past hour 180. Regardless of the differences in the
models, it appears at this time, no significant weather systems will
impact the area through Thanksgiving weekend.


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 326 AM MST Sun Nov 19 2017

VFR conditions can be expected to hold the next 24 hours with just
high level cloudiness drifting through. Winds will be increasing
aloft overnight which could lead to some mountain wave turbulence
but at the surface light diurnal wind patterns can be expected to




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