154
FXUS63 KGLD 181700
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
1100 AM MDT Tue Jun 18 2024

.KEY MESSAGES...

- A marginal risk for severe thunderstorms in far eastern areas,
  Hill City to Gove, near a cold front where storms are expected
  to develop by mid afternoon. If storms develop there, large
  hail and damaging winds would be the primary risks.

- Heavy rainfall is expected from late tonight through the
  overnight hours for areas south of Highway 24 in northwest
  Kansas. Generally 1-2 inches is expected, with some local
  amounts in excess of 4 inches possible. As a result, a Flash
  Flood Watch has been issued for that area through Wednesday
  morning.

- Another round of showers and thunderstorms is likely Wednesday
  night. Locally heavy rainfall will be possible, with the best
  chances north of Interstate 70, including southwest Nebraska.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 230 AM MDT Tue Jun 18 2024

In the near term, the strong winds associated with the low level
jet will gradually diminish through the remainder of the
overnight. The cold front in northeast Colorado will reach the
Kansas border before sunrise and continue southeast this morning
and afternoon. A few showers/isolated thunderstorms may develop
along the front during the morning to early afternoon. However,
the main convection will wait until around 21-22z with the
entire length of the front likely to initiate. At the time, the
front should be just south of the area. However, any slight
variation in frontal location or convective initiation timing
could put the line of storms just into the far southeast
counties, Hill City to Gove in northwest Kansas, where there is
a slight risk for severe storms capable of large hail, damaging
winds and a brief tornado. Those storms will continue to move
southeast with the front through early this evening. Behind the
front, most of the area will see dry conditions through the
afternoon with cooler temperatures and breezy north to northwest
winds. Highs will range from the upper 70s to lower 80s behind
the front, to the upper 80s ahead of it.

Tonight, surface winds will veer to northeast and east in the
post frontal upslope regime. A weak perturbation in the
southwest flow aloft combined with outflow from the storms to
the south will be enough for numerous to widespread showers and
thunderstorms to develop from the late evening hours and through
the overnight. Heavy rainfall is forecast by the models for the
area generally south of Highway 24 in northwest Kansas. HREF
neighborhood probabilities for 3-hour QPF in excess of 3" at 09z
and again at 12z show a low probability centered over that
area. HREF probabilities for greater than 2" is running around
20-40%. In addition, 06z HRRR is showing very heavy QPF in the
same area. All signs indicate flash flooding will be a concern
so issued a Flash Flood Watch for the general area where
heaviest rainfall is expected. Lows tonight will be in the 50s.

Showers and thunderstorms continue into Wednesday morning, but
the signals for heavy rainfall shift southeast and out of the
area. So ended the Flash Flood Watch at 18z. Precipitation
chances become more scattered by the afternoon with additional
rainfall amounts of less than a quarter of an inch. Instability
will be quite limited in most of the area, but some of the
models show the old front nosing north into Logan and Gove
counties during the afternoon with some weak to moderate
instability and deep layer shear of 20-30 kts. Confidence is on
the low side, but there may be a marginal risk for a severe
storm or two Wednesday afternoon generally south of Highway 40
in northwest Kansas. High temperatures will be in the 60s with
cloudy skies. Wednesday night, the front lifts north across the
area with a weak shortwave trough moving through in the
southwest flow aloft. As a result, showers and isolated
thunderstorms will increase in coverage once again. Mean QPF
amounts Wednesday night are generally between a quarter and a
half inch, though higher percentiles suggest 1-2 inches
possible, with best chances for the heavier amounts north of
Interstate 70 this time around including southwest Nebraska. Low
temperatures will be in the 50s.

On Thursday will see subtle height rises as the strengthening
ridge over the eastern CONUS nudges into the central plains.
Precipitation chances should be limited to any lingering showers
in the morning, then late afternoon to early evening scattered
storms in Colorado rotating around the ridge into western
Nebraska. Instability and shear parameters are weak and not
expecting severe storms at this time. Temperatures will warm
back into the middle to upper 80s lows Thursday night will be in
the 60s.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Issued at 230 AM MDT Tue Jun 18 2024

A shortwave trough moves out of the Great Basin on Friday and
into the central plains Friday night, weakening as it does so.
It will bring a chance for showers and thunderstorms from late
Friday afternoon in northeast Colorado the remainder of the area
Friday night. Only weak instability is currently forecast, less
than 500 j/kg, with deep layer shear around 30 kts. Severe
storms are not currently anticipated. A frontal passage does
occur late Friday night with winds shifting to the northwest.
High temperatures will be in the upper 80s to lower 90s and
lows Friday night in the 60s and 70s.

For the period Saturday through Monday, a broad, weak zonal flow
will develop across the central CONUS atop a sprawling ridge
over the southern CONUS. There are occasional shortwaves moving
through the flow which may result in isolated afternoon and
evening thunderstorms. However the pattern is not one
particularly conducive to more than a low-end or marginal severe
threat. Temperatures will also be warming through the period,
from the lower 90s on Saturday, middle 90s on Sunday, and upper
90s by Monday. Lows will generally be in the 60s.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1100 AM MDT Tue Jun 18 2024

KGLD...VFR conditions are expected from taf issuance through
about 08z. Northerly winds gusting to 30kts at taf issuance will
continue this afternoon before veering to the northeast around
13kts this evening through 08z. After 09z, sub VFR cigs are
expected as stratus expands across the area. Rain showers and
perhaps a few thunderstorms will be possible along with some
light reductions in visibility due to mist (BR). Winds will
remain from the northeast around 15kts with perhaps some higher
gusts.

KMCK...VFR conditions are expected from taf issuance through
about 11z. Northerly winds gusting to 30kts at taf issuance will
continue this afternoon before veering to the northeast around
12kts through 11z. After 12z, sub VFR cigs are expected as
stratus expands across the area. Rain showers and perhaps a few
thunderstorms will be possible along with some light reductions
in visibility due to mist (BR). Winds will remain from the
northeast around 11kts.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Flood Watch from late tonight through Wednesday morning for
     KSZ014>016-027>029-041-042.
CO...None.
NE...None.

&&

$$

SHORT TERM...024
LONG TERM...024
AVIATION...99