Area Forecast Discussion
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

FXUS65 KGJT 191535

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
935 AM MDT Fri May 19 2017

Issued at 935 AM MDT Fri May 19 2017

After taking a look at webcams, roads on the mountain passes all
look dry with some wet roads near the divide. There are lots of
breaks in the cloud cover with sun shining through. According to
the latest GOES-16 IR satellite imagery, any enhancement due to
clouds and showers is weakening as soon as it crosses the western
side of the divide in this weak easterly flow, unlike 24 hours
ago. Expect some spotty scattered convective showers the rest of
today with significant lulls and a couple inches more at best over
the higher terrain. This is not significant enough to warrant
keeping winter storm warnings in place so cancelled the remaining
winter weather highlites as the threat for significant snow has
ended. Also, cancelled the Freeze Warning this morning as
temperatures have all risen above freezing in these zones. The
Freeze Watch for tonight through Saturday morning remains in
place. Will update the gridded forecast to reflect the latest
trends and thinking.


.SHORT TERM...(Today through Saturday)
Issued at 415 AM MDT Fri May 19 2017

The closed low pressure system responsible for the return to
winter-like conditions in the mountains and some of the high
valleys was centered over Paonia early this morning. The cold,
unstable, and moisture wrapped system continued to generate light
to moderate snowfall over portions of the central and northern
mountains and adjacent valleys overnight.

The low will shift slowly eastward during the day according to
models. Dynamic and orographic lift not all that impressive
beneath the low circulation. However, instability beneath the cold
core low combined with a shift in flow to the north as the high
pushes eastward is expected to bring an uptick in snowfall over
the mountains this afternoon. Additional accumulations aren`t
expected to be as impressive as during the early phases of this
storm, but still impactful. Isolated embedded thunderstorms may
bring locally higher amounts. Therefore, will continue Winter
Storm Warnings over the central and northern Colorado mountains
and the Winter Weather Advisory for the eastern Uinta Mountains.

Snow decreases tonight as the low center continues to shift over
the central High Plains. Prominent wrap-around moisture may keep a
few isolated showers continuing over the Continental Divide in the
north through sunrise Saturday. Meanwhile, lingering cold may
cause lows to reach freezing again for some of Colorado`s
southwestern valleys. Therefore, will hoist what should be the last
Freeze Watch for awhile for the latter part of the night through
early Saturday morning.

Instability, orographics and residual moisture combined with an
influx of moisture from the northwest will bring scattered showers
and a few thunderstorms to the northern and central mountains
Saturday afternoon. Warmer air begins filtering into the area
which will drive snow levels to near 10,000 feet and above. Though
temperatures will be milder, don`t expect highs to recover to
normal levels until the latter part of the weekend.

.LONG TERM...(Saturday night through Thursday)
Issued at 415 AM MDT Fri May 19 2017

The upper low will move into Ontario and the northern Great Lakes
by Sunday with a few shortwave disturbances rotating around the
periphery, clipping our northern mountains for a chance of some
convective showers developing each afternoon from Sunday through
Tuesday. The ridge of high pressure will build over the Pacific
Northwest by Tuesday night into Wednesday and slide over the CWA
through Thursday, leading to mostly drier conditions. Still kept
some isolated shower activity over the mountains due to
uncertainty in the models that far out in when it moves the
ridge overhead. Regardless, temperatures will rebound and warm
back up to normal levels by Sunday and continue towards above
normal by mid-week.


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 548 AM MDT Fri May 19 2017

Scattered showers threaten to bring CIGS below ILS breakpoints
along the I-70 corridor possibly impacting KRIL, KEGE and KASE
this morning. MVFR VSBY is possible in showers. Showers become
more numerous over the mountains during the afternoon but chances
for showers at TAF sites will be low. Chances decrease further
tonight as the storm which has impacted the area over the past two
days shifts eastward onto the central High Plains.


CO...Freeze Watch from late tonight through Saturday morning for



AVIATION...NL is the U.S. government's official web portal to all federal, state and local government web resources and services.