Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 270937
AFDGJT

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
337 AM MDT Tue Jun 27 2017

.SHORT TERM...(Today through Wednesday)
Issued at 314 AM MDT Tue Jun 27 2017

IR satellite imagery clearing showing a weak wave moving over
Colorado and New Mexico this morning as a well defined area of
high clouds moves overhead. Models continue to indicate an upper
level trough will move through today from about noon onwards as
indicated by a noticeable turning of the winds at both 500mb and
700mb. Both the NAM and GFS do highlight some precipitation for
the area but coverage has really trended downward from yesterday`s
model run so while a few showers and storms are possible, don`t
expect anything too widespread. An upper level jet streak that`s
supporting the trough will move overhead and with deep mixing
still forecast, some gusty winds will be felt at the surface
across much of the CWA. Expect gusts of 25 MPH with a few reaching
between 30 to 35 MPH. As one would expect with all this dry
weather lately, critical fire weather conditions will be met as
described in the fire weather discussion below. For most of us
then, not much change from what we`ve seen over the last few days
with plenty of sun and dry conditions though winds will be pick up
some this afternoon. Favored areas for precipitation look to be
the eastern Uintahs, the San Juans, and also along the Continental
Divide.

On Wednesday, another stronger jet streak will drop down from the
northwest supporting another trough. Wind flow by this time will
have become more zonal (west to east) thanks to the previous
trough flattening out the ridge of high pressure so areas south
will see less of an effect from the jet streak. Areas north of the
I-70 corridor look favored but that`s not really saying much as
coverage, again, will be rather limited. Presently, the WY/CO
border looks to see the best chance at any convection. Deep
mixing is expected again on Wednesday increasing chances for
critical fire weather conditions.

.LONG TERM...(Wednesday night through Monday)
Issued at 314 AM MDT Mon Jun 26 2017

A large area of low pressure across the central Canadian Prairies
will slowly drop into the Upper Great Lakes Wednesday night into
the weekend. This will suppress the hot upper ridge farther to
the west and we can expect a slight cool down going into the late
week period. There could be some light precipitation Wednesday
night as a weak front is forced southward into our CWA by last
piece of the upper jet swinging by. By cool down this means near
to only slightly above normal to end out the week. Though cooler
enough wind near the jet may keep isolated areas of critical fire
weather conditions across the north.

The ridge will be trying to re-establish itself over the
Intermountain West and Rockies over the weekend. However another
strong jet arriving to the border states of the Left Coast will
keep it in mainly in check. There will be a gradual warmup going
into the weekend through early next as the upper flow switches
from northwest to more of a west to southwest flow. The
subtropical high looks to get more established over the southern
High Plains going into the middle of next week which will keep
more a persistent southerly flow directed out of the moist tropics
into the Southwest.
&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 314 AM MDT Tue Jun 27 2017

A few showers and storms are possible over the mountains today but
they should pose no threat to TAF sites. Expect gusty winds in the
afternoon of 25 to 30 MPH, maybe a little higher at times. VFR
conditions continue.

&&

.FIRE WEATHER...
Issued at 314 AM MDT Tue Jun 27 2017

A Red Flag Warning has been issued for most of eastern Utah and
western Colorado thanks to plenty of dry fuels and low humidities.
A trough will move through today and though the pressure gradient
doesn`t tighten `too` much, deep mixing will likely tap into a
jet streak and bring this wind to the surface. Gusty winds of 25
MPH to 35 MPH will be common and with the other variables in
place, any fires that start will likely spread rapidly.

Tomorrow, another stronger jet streak will move overhead as deep
mixing is expected to occur again. With almost no change to
moisture or fuels, critical fire weather conditions look likely.
However, did leave Fire Weather Watch as is because confidence a
little bit shaky for southern zones getting strong enough winds.
Still plenty of time to upgrade as necessary and will also allow
day shift to see how today pans out with current highlights.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Red Flag Warning from 11 AM this morning to 8 PM MDT this
     evening for COZ200-202-203-207-290>292-294.

     Fire Weather Watch from Wednesday afternoon through Wednesday
     evening for COZ200-202-203-207-290-291-294.

UT...Red Flag Warning from 11 AM this morning to 8 PM MDT this
     evening for UTZ486-487-490-491.

     Fire Weather Watch from Wednesday afternoon through Wednesday
     evening for UTZ486-487-490-491.

&&

$$

SHORT TERM...TGR
LONG TERM...15
AVIATION...TGR
FIRE WEATHER...TGR



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