Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 260957

Area Forecast Discussion
National Weather Service Grand Junction CO
357 AM MDT Sun May 26 2019

.SHORT TERM...(Today through Monday)
Issued at 357 AM MDT Sun May 26 2019

Here we go again. Hopefully you can get outside today because more
rain and snow is on the way. Until then, expect another relatively sunny
day though clouds will be on the increase from the afternoon
onwards. The closed low off to our west will start moving eastward
today in response to the upper level jet digging into the base of
the low and and also moving eastward. As this occurs, the
subtropical jet will be moving over Arizona and New Mexico. While
the strongest portion of the jet will stay to our south, we`ll
still see some 90kt upper level winds as the jet, as a whole,
moves to the east. This upper level support looks to provide
enough lift to get some convection going this afternoon, generally
from a line from about Telluride, up to the Grand Mesa and Flat
Tops and all areas eastward. This is also where the best CAPE
lines up and though moisture will be on the low side, there should
be enough available for convection to fire. Soundings keep an
inverted V-profile in place so expect another day of gusty outflow
winds from any convection, including showers, that form. High
clouds will also start moving in from about mid-afternoon onwards,
give or take, as the low slowly gets closer. Finally, the other
concern will be some gusty surface winds today in response to the
tightening pressure gradient. Gusts of 30 mph will be common this
afternoon with some spots flirting with 40 mph at times. South
eastern Utah will need to be watched for a possible advisory but
with midlevel clouds moving in, believe they will keep the
stronger winds aloft from mixing to the surface. Of course, if the
clouds don`t materialize, get ready for some stronger gusts.

Sunday night into Monday morning will be generally quiet but from
daybreak onwards, things will get going. The low pressure will be
over the Las Vegas area and will bring some precip to eastern Utah
and far western Colorado before spreading to much of the area by
midafternoon. Expect some showers and thunderstorms as the low
approaches given the lift associated with the low. Snow levels
will be around 9K feet to start with so some snow is possible
above that level with with such warm antecedent conditions in
place, don`t expect much, if any, accumulation on road surfaces
during the day. By evening, snow levels will continue to drop as
H7 temps drop to the -3 to -5C range. This is when some
accumulation is likely. Debated on issuing a watch for the
upcoming storm but some uncertainty remains, as they always do
with late spring storms, so another run or two won`t hurt. Will
issue a special weather statement to highlight the fairly drastic
change in conditions from today to tomorrow.

.LONG TERM...(Monday night through Saturday)
Issued at 357 AM MDT Sun May 26 2019

Deep and cold upper level low will be lifting northeast across the
Four Corner Monday night with snow levels quickly dropping in the
High Country. Late holiday travelers will likely be impacted with
rain/snow with some potential for heavy snow above the 9k mark,
especially across the San Juans Monday night, spreading northward
into our central and northern mountains by Tuesday morning. As the
low jumps the divide, flow aloft will swing to the north and
northwest with moisture wrapping back around. Rain and mountain
snow showers will continue for much of the day on Tuesday with
temperatures a solid 15 to 25 degrees below seasonal norms. This
system is expected to kick out across the Plains Tuesday night.

More zonal pattern tries to set up from Wednesday through Saturday
with a series of waves passing through. Should see at least
scattered showers each afternoon and evening with the higher
elevations favored. A little more organized wave appear to drive
through on Thursday, so a little uptick anticipated. Temperatures
will gradually climb back toward normal by the end of the week.


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 357 AM MDT Sun May 26 2019

Some isolated showers and storms will fire over the mountains
today with KASE and KEGE possibly being affected. Not enough
confidence to include in TAFs at the moment however. The big story
today will be the gusty southerly winds of 25 to 30kts, possibly
higher at times, from 18Z through 00Z. High clouds will also be on
the increase from midafternoon onwards and will start to lower
overnight. Even so, VFR conditions will be the rule for the next
24 hours




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