654
FXUS63 KGLD 050225
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
725 PM MST Wed Dec 4 2024

.KEY MESSAGES...

- Medium confidence (70%) of fog formation across Cheyenne and
  Kit Carson counties in Colorado Thursday morning. Dense fog is
  possible, mainly along/west of Highway 59.

- Backdoor cold front tonight causing cooler temperatures
  Thursday.

- Gradual warming trend through weekend.

- Low confidence (20%) for precipitation to occur with potential
  storm system early next week.

&&

.UPDATE...
Issued at 725 PM MST Wed Dec 4 2024

As the 00z models arrive, they (NAM/HRRR/RAP) continue to
advertise a cold front backing into the area overnight through
Thursday morning. This latest guidance continues to push the
lower cloud deck (stratus) further west compared to 6 hours ago,
favoring much of eastern Colorado with some considerable morning
cloudiness. RAP/HRRR/CONSHORT models also showing visibility
reductions in fog across parts of Cheyenne and Kit Carson
counties from around 12z-17z. West of Highway 59 where some snow
cover continues to be present, these models are hitting those
areas hardest with the lowest visibility reductions and dense
fog is possible with visibilities as low as 1/4 mile, maybe
lower. Otherwise, have increased cloud cover and updated
temperature/dewpoint/wind grids. Low temperatures look to be
generally in the upper teens to middle 20s.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 205 PM MST Wed Dec 4 2024

Latest upper air analysis shows a ridge over the Great Basin.  To
the east of it a closed low was over the Great Lakes; this has led
to northwest flow over the Plains.

At the surface a cold front was moving south over Nebraska away from
the closed low.  Behind the front temperatures were in the upper
30s, while temperatures were in the mid/upper 50s ahead of it.

For the rest of the day light northwest winds will continue.  The
winds will be light and variable this evening as the front moves
through.  Behind the front winds gradually turn to the east or south
overnight as the surface high pressure moves through.  The front
will stall over Eastern Colorado.  Along and ahead of the front
moisture advection will occur.  This may allow for the formation of
fog where the snow field will cool temperatures more.

Thursday and Friday the cooler air mass is gradually pushed east of
the forecast area.  Meanwhile the ridge currently over the Great
Basin will slide slowly east onto the Plains.  With the jet stream
to the north and east, am expecting dry weather with gradually
warming temperatures.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 205 PM MST Wed Dec 4 2024

The main focus for this part of the forecast continues to be upper
level short wave trough moving through Monday and Tuesday.

This weekend will be rather warm for this time of year as the ridge
overhead slowly moves east.  Later on Sunday an upper level trough
will move toward the Plains.

Looking to later in Sunday and Monday, the operational GFS and ECMWF
have both shifted the main part of the approaching trough south. The
majority of the ensemble members for the ECMWF, GFS, and Canadian
keep the precipitation south and east of the forecast area.  Looking
at the pattern overall, this is resembling split flow, with the
secondary storm track being north of the forecast area.

This is a similar weather pattern to the trough that
moved south of the forecast area on Thanksgiving.  A week out that
event was looking quite concerning regarding impacts for
Thanksgiving.  However, as the week progressed, the models began to
show more of a split flow pattern, which ended up pushing the
precipitation to the south of the forecast area.  With this in mind,
foresee the precipitation remaining south and possibly east of the
forecast area unless there is a dramatic change in the upper level
flow (which could happen, but is becoming less of a possibility each
day).

Accompanying the upper level short wave trough will be a cold front.
Models agree the front will move through Sunday night.  As such
highs will be cooler Monday and Tuesday.  Temperatures will warm
after Tuesday due to the upper level ridge moving back over the
Plains.

Terms:
GFS, Canadian, and ECMWF are global forecast models

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 340 PM MST Wed Dec 4 2024

KGLD...VFR conditions are expected through about 08z with winds
generally light and variable. From 09z-16z, sub VFR conditions
are possible in stratus and maybe some fg/br as a cold front
backs into the area. I`ve included a TEMPO group for some BR and
sub VFR cigs as confidence is high enough to introduce into the
forecast. After 17z, southerly winds increase with gusts to
around 25kts through 23z.

KMCK...VFR conditions are expected through the period. A
northwesterly wind up to 10kts at taf issuance will veer to the
northeast at similar speeds from 03z-10z. From 11z-16z, winds
are forecast to be light and variable. After 17z, southerly
winds up to 11kts with perhaps a few higher gusts are
anticipated. Presently, the speed of the cold front backing into
the area should be west of the terminal and thus no sub VFR
conditions are anticipated. Will be watching the 06z-12z
timeframe for the possibility of stratus and fog and update the
taf if conditions warrant.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.

&&

$$

UPDATE...99
SHORT TERM...JTL
LONG TERM...024/JTL
AVIATION...99