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Area Forecast Discussion (AFD)

Issued by Grand Junction, CO (GJT)

                            
000
FXUS65 KGJT 250945
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
345 AM MDT Tue Jun 25 2019

.SHORT TERM...(Today through Wednesday)
Issued at 345 AM MDT Tue Jun 25 2019

A departing ripple in the zonal flow aloft has allowed some light
returns to persist on radar early this morning, though this
activity doesn't appear to be reaching the ground. Upper level
flow will gradually shift to the southwest throughout the day
today as the subtropical high begins to amplify and progress
westward. This will result in the onset of a dry and benign
weather pattern for eastern Utah and western Colorado, though some
mid and high level clouds will continue to pass overhead. An
isolated shower or two may develop over the far eastern Uinta
Mountains or along the Continental Divide this afternoon as 
another weak shortwave treks across the region. Daytime highs will
rebound back to or slightly above seasonal normals with some 
locally breezy conditions developing across the north as the 
gradient begins to tighten aloft. A quiet night is on tap for the 
region tonight with mild overnight lows in response to the 
strengthening warm and dry southwesterly flow. This trend 
continues and becomes more prominent tomorrow as an area of low 
pressure elongates off the coast of the Pacific Northwest and as 
the high intensifies to our southeast. The resulting gradient over
eastern Utah and western Colorado will support deep mixing during
the afternoon and evening hours, see temperatures rise to above 
normal levels, and allow humidities to plummet. An exception will 
be along the Divide where orographics will combine with daytime 
heating to produce some isolated showers during the afternoon and 
evening hours. 

.LONG TERM...(Wednesday night through Monday)
Issued at 345 AM MDT Tue Jun 25 2019

Wednesday night through the end of the work week will see the
Pacific low continue to spin over the northwestern CONUS with the
ridge extending across and dominating the southern Plains. This
will result in a bit of a rinse-and-repeat forecast over eastern
Utah and western Colorado under persistent southwest flow aloft.
High temperatures in the 90s, potentially reaching the lower 
triple digits, for the valleys with breezy conditions and partly
to mostly sunny skies will prevail for much of the area.
Therefore, the prolonged Fire Weather Watch remains in effect with
this morning's forecast package. As the ridge axis amplifies over
the Midwest on Saturday the Pacific low will be deflected to the
northeast, shunting any chance for precipitation well away from
our forecast area. Way out into the extended period the models
begin to indicate the dissipation of the ridge as another trough
nudges into the Pacific Northwest late into the weekend and into 
early next week. However, the Euro is substantially more 
aggressive than the GFS at this time so overall guidance favors 
the dry weather continuing as we end the month of June. Better 
late than never, since June is supposed to be our driest month 
climatologically!

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 221 AM MDT Tue Jun 25 2019

Apart from some passing mid and high level clouds, dry conditions
with widespread VFR conditions are expected through the TAF period
under southwest flow aloft. The upper level gradient will begin 
to tighten today and this evening resulting in some locally breezy
conditions to 25 kts, particularly across the north.

&&

.FIRE WEATHER...
Issued at 345 AM MDT Tue Jun 25 2019

Several days of near-critical fire weather conditions will be
possible from tomorrow through at least Friday across much of the
forecast area. Continued southwesterly flow along with tightening
pressure gradients will keep surface conditions warm, dry, and 
windy; thus the fire weather watch continues for portions of 
southwestern Colorado for each afternoon and early evening period.
Critical conditions will be possible at elevations below about 
7,000 feet along and west of a line from roughly Cortez to Grand 
Junction to 25 miles west of Craig Wednesday through at least
Friday.

If you're reading this, now is the time to make sure your zone's 
fuel status is up-to-date.

&&

.HYDROLOGY...
Issued at 345 AM MDT Tue Jun 25 2019

Recent rainfall and continued snowmelt increased runoff in some 
areas resulting in elevated river levels the past few days. 
However, cooler temperatures this past weekend slowed the snow 
melt temporarily which allowed water levels to decrease slightly.
However, snowfall in the northern portions of the forecast area 
will likely contribute to additional rises given the warm 
temperatures expected this week.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Fire Weather Watch from Wednesday afternoon through Friday 
     evening for COZ207-290-292.

UT...None.
&&

$$

SHORT TERM...MMS
LONG TERM...MMS
AVIATION...MMS
FIRE WEATHER...TGJT
HYDROLOGY...TGJT