Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 191007
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
407 AM MDT Sun Mar 19 2017

.SHORT TERM...(Tonight through Sunday night)
Issued at 358 PM MDT Sat Mar 18 2017

Increasing high clouds will take a bit of the edge off high
temperatures today as max temps should be close to but generally
just short of record highs.

The upper ridgeline had moved over the high plains this morning
with strengthening southwest flow spreading over the area. A very
weak upper shortwave trough is evident on satellite over eastern
Utah which will bring a bit of high cloud cover to the area and
take the edge off the record high temperatures the region has
experienced. Southwesterly flow will increase throughout the day
as the gradient tightens aloft. So today will be will be another
warm, breezy day. Southwest flow aloft will continue overnight and
middle and high clouds with gradually increase and start
lowering.

.LONG TERM...(Monday through Saturday)
Issued at 358 PM MDT Sat Mar 18 2017

The arrival of the new work week begins the transition from a quiet
March to a more progressive weather pattern. Strong southwesterly
flow will bring another embedded shortwave on Monday. While this
disturbance is not strong and lacks substantial moisture and
energy, it should be sufficient enough to generate some isolated
to even scattered (if going with the continued bullish GFS
solution) showers over the mountains with the central Colorado
mountains favored. 700mb temperatures with this shortwave range
from 3 to 6 degrees C so any precipitation is expected to fall as
rain with snow showers isolated to the highest mountain peaks
above 10kft. A weak, dirty ridge builds in for 12 to 18 hours on
Tuesday as the broad Pacific trough that will be impacting our
area the latter half of the week moves inland.

Southwesterly flow will increase ahead of the aforementioned Pacific
storm on Wednesday with the nose of a ~100kt jet arriving Wednesday
morning. This will result in some gusty prefrontal winds
persisting through Thursday. The southwesterly flow will also
result in increased cloud cover and the chance for precipitation
with showers, albeit orographic showers for now, developing as
early as Wednesday morning. Extended models continue to disagree
on timing, setup, and track of the event with the GFS being more
progressive and kicking the trough through the region by Thursday
night and the Euro lagging behind at least 6 to 12 hours, bringing
the storm axis further south. Regardless, this still looks to be
the first impressive storm the region has seen in a while with
numerous to widespread precipitation expected for western
Colorado and eastern Utah Wednesday and Thursday. Precipitable
water values look to peak from 0.50 to 0.70 inches or 167 to 233%
above normal. 700mb temperatures drop to -2 to -5 degrees C
Thursday afternoon before the bulk of the colder air moves in on
Friday when 700mb temperatures drop to the -5 to -10 degrees C
range. Snow level forecast remains tricky with this warmer system
and, since the models continue to differ on frontal passage,
precipitation type and estimated snowfall accumulations for those
higher valleys will have to be hashed out later. With regards to
temperatures, the passage of the cold front towards the end of
next week will knock temperatures back down to their seasonal
norms, or at least a little closer to them.

As for the rest of the extended forecast, drier conditions look to
return for Friday and Saturday as a weak ridge builds over the area.
This ridge will not persist as yet another longwave trough moves
into the region by the end of next weekend as the progressive
weather pattern continues. This is supported in both the 6 to 10 day
as well as the 8 to 14 day Climate Prediction Center Precipitation
outlooks, which both hint at odds favoring above normal
precipitation for much of the western CONUS. So while March may not
have come in like a lion it appears it may go out as such!

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1103 PM MDT Sat Mar 18 2017

VFR conditions will continue the next 24 hours at all TAF sites.
CIG heights will remain well above ILS values. Expect breezy winds
generally out of the southwest again this afternoon.


&&

.FIRE WEATHER...
Issued at 358 PM MDT Sat Mar 18 2017

A ridge of high pressure will be east of the area today with a
trough moving into the western Great Basin. This will allow
southwest winds to strengthen over the region this afternoon.
Relative humidities are expected to drop into the 15 to 25 percent
range this afternoon, but may drop lower with record or near
record heat persisting. The gusty winds combined with warm
temperatures, low humidity and still dormant or dry vegetation
will require a heightened fire weather awareness. Check the latest
forecast before attempting any burning through this weekend as
conditions can change rapidly. The potential will be greatest for
elevations below 8000 feet.

&&

.HYDROLOGY...
Issued at 358 PM MDT Sat Mar 18 2017

Prolonged period of record or near record high temperatures will
continue to impact the region through tomorrow. This will
accelerate snowmelt resulting in increased flows on area waterways
and slow but steady rises in river levels. Temperatures are
expected to cool next week as clouds and the chance for showers
return to the area, which will help to slow the snowmelt. A storm
carrying major moisture potential is possible during the middle
of next week in the form of both rain and snow. Will need to
monitor for rain on snow issues that could develop mid to late
next week with the changing snowpack levels.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&

$$

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



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