061
FXUS65 KGJT 070017
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
617 PM MDT Mon May 6 2024

.KEY MESSAGES...

- Light mountain showers will linger through the night, with an
  expected upturn in activity around daybreak tomorrow morning
  with an approaching disturbance. Winter Weather Advisories
  have been extended through tomorrow afternoon.

- Windy conditions return tomorrow with gusts of 40-50 mph
  likely across the region. Numerous Wind Advisories have been
  issued.

- In the wake of tomorrow`s disturbance, clear skies and much
  colder air will lead to a threat of sub-freezing temperatures
  for the lower elevation valleys. Freeze Watches have been
  issued for susceptible areas.

- Cool and unsettled weather will linger through the remainder
  of the week, with a parade of disturbances keeping chances of
  light mountain showers in the forecast most afternoons.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 321 PM MDT Mon May 6 2024

Showers have lingered across northwest Colorado, and even into
portions of central Colorado, well into the afternoon hours today,
although we are starting to see a downturn in activity as subsidence
finally takes hold. Breezy conditions also continue across the
northern half of the CWA thanks to a modest 25-35 knot northwesterly
700mb jet still lingering over the north. This jet combined with
favorable downsloping conditions in the Uinta Basin has led to the
need for a Wind Advisory for the Eastern Uinta Basin through 8PM
this evening. Elsewhere, aside from a stray strong gust here and
there, winds have remained sub-advisory. The same cannot be said for
tomorrow. As today`s low ejects into the Northern Plains, the jet
will lift back north overnight, with the core of a 90-100 knot
northwesterly 200mb jet centered over eastern Utah and western
Colorado by 6AM tomorrow morning. Moving downward, at 700mb, two
distinct jet streaks will be in place over the region, one over
Southeast Utah and Southwest Colorado, and one over far Northeast
Utah and northwest Colorado. This event is not quite as anomalous as
yesterday`s event, but it`s still registering in the 90th percentile
of the 1991-2020 climatology. Under northwest flow this time, and
with that split 700mb jet, the areas looking at high winds are a bit
different. Wind Advisories go into effect for the Eastern Uinta
Basin and areas of the Gunnison River Valley at 6AM, with more
Advisories for the entire I-70 corridor from Green River to Edwards
and for the Southwest Colorado and Southeast Utah valleys joining at
9AM. Widespread gusts of 50-60mph will be possible in these areas
through the day.

In addition to all the wind, an approaching shortwave will drive
another strong cold front through the area during the day tomorrow.
This will bring another round of snow to the northern and central
Colorado Divide mountains, mainly during the morning hours. Amounts
have come up a bit for these areas, with 6-10 inches possible above
8000 feet. Combined with the expected gusty winds and the timing
being around the morning commute, have elected to extend the current
Winter Weather Advisories through tomorrow afternoon. Rain showers
will be possible along the front at lower elevations. Behind this
cold front, a reinforcing shot of cold air and clearing skies under
subsidence will allow temperatures to fall into near-record low
territory by Wednesday morning, with many areas seeing sub-freezing
temperatures. And, unfortunately, much of the lower elevations of
eastern Utah and western Colorado are already well into the growing
season. As such, Freeze Watches have been issued for Tuesday night
into Wednesday morning. Now would be the time to prepare susceptible
vegetation for the coming cold snap. Daytime highs won`t fair much
better, with tomorrow`s forecast topping out 10-15 degrees below
normal for early May. Certainly, the next few days will feel more
like early spring than almost summer.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 321 PM MDT Mon May 6 2024

The theme of the day is Rex block as this stubborn...blocky pattern
will persist through the end of forecast into early next week. If
you like cool and unsettle conditions then the news is good...for
the rest of us not so much. The Rex pattern starts Wednesday with
our current system rotating up into the Dakotas where is stalls and
takes on a more East-to-West orientation.
The blocking ridge is meanwhile is sitting over the Canadian
Prairies. The only good news on Wednesday will be the cold air is so
expansive that the lack of a thermal gradient across the region will
keep the winds in check. This will be at the expense of high
temperatures some 10 to 20 degrees below normal. Cold air aloft and
W/NW orographics are likely to keep some snow showers going over our
northern and central mountains...but with minimal impacts expected.
By Thursday the Plains system will be splitting with one piece
retrograding back into the Intermountain West to form the next Rex
pattern with high pressure building into the Pacific Northwest.
Grand Junction and Seattle could end up with the same forecast high
for Thursday with the former cooler than normal and the latter
warmer. Again cooler temperatures aloft and lingering moisture will
keep a threat of afternoon showers in place across the higher
terrain and adjacent valleys. The lower elevations look to remain on
the dry but cool side. The forecast beyond this gets a bit fuzzy as
the models are not handling this blocky pattern very well. When and
where this Rex Low ejects will decide when and who gets the better
precipitation chances later into the weekend. Otherwise the low
spinning to the West of the 4 Corners into Friday the Southern CWA
will have the better chances of a passing shower. The airmass will
be moderating a bit by late week and this should push snow levels
above the 9500 foot mark with little impact expected during the
daylight hours. The forecast for now has showers lingering into
Sunday afternoon with some reflection of the trough in the GFS or a
more closed circulation in the EURO. Either way the trend of warmer
conditions will continue to push snow levels higher and bring
temperatures closer to normal by late in the forecast.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 554 PM MDT Mon May 6 2024

Gusty winds of 25 to 35 mph continue at this hour but will start
to decrease over the next few hours. Ceilings will persist for
KASE, KEGE, and KGUC but should remain VFR though they will
likely hover around ILS breakpoints from time to time. Another
system rolls through by the early morning hours and snow will
again spread over much of northern Colorado with terrain
obscuration likely through the day. This system will also bring
another round of gusty winds reaching between 40 to 50 mph,
maybe higher at times.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Winter Weather Advisory until 6 PM MDT Tuesday for COZ004-010-
     013.
     Wind Advisory from 9 AM to 9 PM MDT Tuesday for COZ006>008-
     021>023.
     Freeze Watch from Tuesday evening through Wednesday morning
     for COZ006-007-011.
     Wind Advisory from 6 AM to 9 PM MDT Tuesday for COZ011-014.
UT...Wind Advisory from 9 AM to 9 PM MDT Tuesday for UTZ022-027.
     Freeze Watch from Tuesday evening through Wednesday morning
     for UTZ022-027-029.
     Wind Advisory from 6 AM to 9 PM MDT Tuesday for UTZ024.
     Wind Advisory until 9 PM MDT this evening for UTZ024.

&&

$$

SHORT TERM...BGB
LONG TERM...15
AVIATION...TGJT