757
FXUS63 KDDC 072359
AFDDDC

Area Forecast Discussion
National Weather Service Dodge City KS
559 PM CST Fri Feb 7 2025

.KEY MESSAGES...

- Dense fog likely (greater than 60% chance) tonight for much of
  southwest Kansas, and a Dense Fog Advisory is now in effect
  for all but the far western counties tonight through early
  Saturday morning.

- Two storm system early next week will yield accumulating snow
  across much of Kansas.

- The second of the two systems Tuesday Night into Wednesday
  looks to be the more impactful system with more widespread 2"+
  snow potential and very cold temperatures.

&&

.DISCUSSION...
Issued at 356 PM CST Fri Feb 7 2025

There are several forecast challenges over the coming days and into
next week, including dense fog tonight and snow/cold early to mid
next week. This afternoon`s RAP analysis and water vapor imagery
revealed a largely zonal pattern across much of the CONUS. There was
an upper level jet streak moving across the Great Basin region east-
northeast toward the Northern Plains. The shortwave trough tied to
this jet streak was pushing east across Montana, which was where the
most unsettled weather was occurring re accumulating snow. The
surface wind field across our southwest Kansas region was slowly
responding to the increasing pressure falls with a southeasterly
wind becoming more uniform across Kansas into northern Oklahoma.
This is important because higher dewpoints were found just to our
south across northern Oklahoma which will slowly advect
northwestward this evening. The increased dewpoints will eventually
manifest as fog, likely dense, beginning late this evening most
likely.

HRRR runs today have been quite aggressive in visibility falling to
1/4 mile by 03Z and after, along with other CAMs. The HREF
probabilities, thus, are quite high for dense fog with a growing
area of 50%+ probabilities 1/4 mile visibility, especially after 06Z
across the eastern half of the DDC CWA. We have issued a Dense Fog
Advisory for the above discussed reasoning from 9 PM CST tonight to
9 AM tomorrow morning. The dense fog is likely to erode fairly
quickly from northwest to southeast when the next cold front moves
south early Saturday morning. North winds behind the front will be
strong, and 5-8 mb/3h MSLP rises in the morning will support wind
gusts 35 to 45 mph at times, particularly in the 14-18Z time frame
Saturday morning. The pressure gradient will slowly relax in the
afternoon with winds tapering off to around 15 mph late in the
afternoon.

Looking ahead to early next week, the next forecast challenge will
be accumulating snow. Successive shortwave trough passages will lead
to enhanced 800-700mb frontogenesis, which will be the primary
forcing mechanism for ascent. The first of these disturbances will
arrive late Monday/Monday Night at the same time an arctic front
meets up with advancing gulf moisture from Texas. The global model
consensus for the best window of light accumulating snow with Wave
#1 is mid evening Monday through roughly mid morning Tuesday. Latest
100-member Grand Ensemble 75th percentile shows around 1/2 to 1"
snowfall focused mainly on the northeastern half of the DDC CWA. The
first wave will move east quickly on Tuesday, but will be followed
quickly be a slightly stronger Wave #2 Tuesday Night into Wednesday.
With Wave #2, 800-700mb frontogenesis will be stronger as the
thermal gradient will be stronger along with better convergence and
deformation in this layer as well. 700mb temperatures will be colder
as well, and this would loosely translate to higher snow-to-liquid
ratios of around 15:1. For Dodge City in particular, latest 25-75th
percentile QPF shows 0.07-0.31" range off the Grand Ensemble, and if
we use a conservative 12:1 SLR, that would result in 0.8-3.7"
snowfall. The upshot is that the 2nd system is likely to be the more
impactful for southwest Kansas with colder temperatures/wind chills
and more accumulating snow.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 553 PM CST Fri Feb 7 2025

Light upslope winds and a moist air mass will lead to fog
formation by 03-06z at KGCK and KDDC. Visibilities will likely
drop to 1/2 mile or less. There is uncertainty in how far east
the fog will develop so that KHYS may keep MVFR visibilities and
CIGS. North winds at 10-12 kts will develop after 06z and then
increase to 15 to 20 kts by 12z in the wake of a cold front. The
stronger winds will break up the fog by 10-11z at KGCK and
KDDC. With daytime heating by 14-15z, expect north winds to
increase to 20-25 kts along with VFR conditions.

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory from 9 PM this evening to 8 AM CST Saturday
for KSZ030-031-043>046-062>066-075>081-085>090.

&&

$$

DISCUSSION...Umscheid
AVIATION...Finch