Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 272044
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
144 PM MST Mon Feb 27 2017

.UPDATE...
Issued at 144 PM MST Mon Feb 27 2017

Forecast still on track, with confidence highly increasing on the
heavy snow/rain band across the Four Corners tonight. Upped the
amounts on the Animas Valley to Pagosa Springs warning to 6-12
inches total in anticipation of 2 to 3 inch per hour snow rates at
times overnight toward daybreak. Looking at rain/snow line
tonight around 6000 ft across the Four Corners, but then
decreasing to about 5000 ft by daybreak, and convection pushing
the snow level down as well. Some of this moisture still expected
to reach Gunnison valley as well in favorable south-southwesterly
flow.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 331 AM MST Mon Feb 27 2017

Updated this morning`s low temperatures as increasing cloud cover
and a bit of wind kept temperatures 5 to 8 degrees warmer than
expected. The next storm system appears to be strengthening over
the Pacific NW with its cold front sweeping across northern NV and
into NW UT. A strong polar jet rounds the bottom of the trough and
curves toward the north over WY and the high plains, while to
subtropical jet is arcing north over southern CA. The surface cold
front should push through NE UT into extreme NW CO late this
afternoon and early evening then progress through most of the
forecast area overnight and hanging up over SW CO Tuesday morning.
It appears the front will push through SW CO by late Tue morning
or early in the afternoon. As this occurs significant moisture
from the subtropical flow should be injected into the flow over SW
CO. Thus, the precipitation will be more focused on SW Colorado
and SE Utah.

Have enough confidence in snowfall over the lower elevations of
SW CO to upgrade the Winter Storm Watch over the Durango and
Pagosa Springs areas, zones 22 and 23, to Winter Storm Warnings
starting at 01Z this evening through Tuesday afternoon (00Z
Wednesday). Decided to add the Cortez vicinity, zone 21 as an
advisory. Also include zone 14, the Gunnison vicinity, in an
advisory as well for the same time period.

.LONG TERM...(Tuesday night through Sunday)
Issued at 331 AM MST Mon Feb 27 2017

By sunset Tuesday the cold front will be pushing out of the
forecast area to the south and east. The flow will have shifted to
the northwest shifting the focus of snowfall over the San Juan
mountains to areas north of Red Mountain Pass, with the northern
and portions of the central mountains receiving better orographic
snow. Most of the moisture will lift out of the area by Wednesday
morning, with only remnant orographic snowfall continuing over the
CO northwest mountains. The pattern will persist through Friday,
then the flow aloft will become more westerly and final
southwesterly on Sunday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 943 AM MST Mon Feb 27 2017

Aviation conditions will continue to deteriorate area-wide across
all terminal sites this afternoon. CIG heights will lower into
MVFR and occasionally IFR ranges later this afternoon as a storm
system moves in from the west. Southwesterly winds will also be on
the increase, especially in mountain locations as a strong jet
moves in aloft over the region. LLWS and turbulence aloft is
likely. VIS conditions will generally remain good through the
early afternoon until precipitation begins. MVFR to occasional IFR
VIS in heaviest precipitation this evening and overnight.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Winter Weather Advisory until midnight MST Tuesday night for
     COZ009-010-017.

     Winter Storm Warning until midnight MST Tuesday night for COZ012-
     018-019.

     Winter Weather Advisory from 6 PM this evening to 5 PM MST
     Tuesday for COZ020-021.

     Winter Weather Advisory from 6 PM this evening to 11 PM MST
     Tuesday for COZ014.

     Winter Weather Advisory until 5 AM MST Tuesday for COZ004-013.

     Winter Storm Warning from 6 PM this evening to 5 PM MST Tuesday
     for COZ022-023.

UT...Winter Weather Advisory until 9 PM MST this evening for UTZ023.

     Winter Weather Advisory until midnight MST Tuesday night for
     UTZ028.

&&

$$

UPDATE...JAM
SHORT TERM...CC
LONG TERM...CC
AVIATION...MAC



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