356
FXUS63 KGLD 160831
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
231 AM MDT Tue Jul 16 2024

.KEY MESSAGES...

- Severe chances again on Tuesday with wind the primary hazard,
  but also a few instances of marginally severe hail possible.

- Temperatures closer to normal beginning tomorrow and
  continuing through the weekend.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 215 PM MDT Mon Jul 15 2024

A pattern changes is underway as the upper ridge that has been
responsible for the extreme heat moves back to the western CONUS
and northwest flow aloft develops over the central plains. This
will result in temperatures closer to normal beginning on
Tuesday as well as better chances for showers and thunderstorms
beginning tonight. Scattered showers and thunderstorms will
develop in eastern Colorado late this afternoon and evening and
move into northwest Kansas and southwest Nebraska tonight.
Other more scattered activity may develop south on Interstate 70
near a surface trough this afternoon. Main hazard with any of
these storms will be strong to possibly severe wind gusts of
greater than 60 mph. Similar to last night, some blowing dust
will also be possible. Storm chances will gradually end
overnight as they move east and out of the area. Lows will be in
the 60s.

Tuesday will start mostly sunny then scattered thunderstorms
developing towards mid to late afternoon. Highs will be in the
lower 90s. There will be a shortwave trough coming down in the
northwest flow as well as low level convergence along the
accompanying surface feature. Instability is somewhat limited in
western areas, less than 1000 j/kg, but there is some modest
increase further east. Deep layer shear will be 30-40 kts,
highest in southern areas. So expect to see slight to marginal
severe chances, with wind the primary hazard but perhaps some
marginally severe hail with the increase in instability and
shear further south and east. Models fairly robust with the
precipitation chances, first in Colorado then diving southeast
into areas south of Interstate 70 in the evening. HREF 6-hour
QPF between 00z-06z is generally between a quarter and a half
inch. HREF shows low probabilities, less than 10%, of greater
than one inch in parts of northwest Kansas between 00-06z
Tuesday evening. Precipitation gradually ends after midnight
with lows in the lower 60s.

Wednesday will see post frontal easterly winds much of the day,
becoming southeast in the afternoon, with cooler temperatures
and highs in the lower 80s. Another disturbance in the northwest
flow will result in scattered thunderstorms in Colorado by the
afternoon which will move southeast with the mean wind Wednesday
night. Given that storm motion best chances for precipitation
will be west of Highway 25, with only slight chances further
east. Deep layer shear is good in the northwest flow, but
instability not particularly impressive and generally limited
to Colorado, suggesting a marginal severe risk there at best.
QPF is generally less than a tenth of an inch, with some spotty
amounts in Colorado up to a quarter of an inch. Low temperatures
will be in the upper 50s to lower 60s.

Not much changes for Thursday. Northwest flow continues but
there are only hints of a slight perturbation in the models.
Shear continues to be high and instability is better,
particularly in western areas. However, given the relative lack
of forcing coverage for afternoon and evening storms will be
relatively low. Cannot rule out an isolated severe storm or two
given the environmental parameters. Highs will be in the mid
80s and lows in the lower 60s.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 227 AM MDT Tue Jul 16 2024

Little has changed from 24 hours ago. The long-term looks to be a
fairly active period. A 500mb high pressure system will be sitting
over the Four Corners area with a trough over the Great Lakes. This
will put us under generally northwesterly flow the period. There are
some weak ridges and troughs that will keep the flow "interesting."
GEFS is showing a trough moving south, over the Great Plains during
the weekend that may force the high to retrograde more into the
Great Basin area. This would also bring in a more northerly flow and
give upper level support for convection.

In the lower-levels, we look to start with southerly 850mb flow,
which will pull moisture from the SE CONUS and bring it into the
CWA. Friday night, the GFS, CMC-NH, ECMWF, and GEFS are all showing
a low moving across the Northern Plains and extending a cold front
down through the CWA. This front would likely be the best forcing
mechanism in the period and could fire numerous storms. Due to how
far out this event is, specific hazards are difficult to pinpoint,
however guidance is suggesting we could have a high precipitation
event. Some of the parameters supporting this include PWATS ranging
from 1.2-1.7 inches, low-levels becoming easily saturated, a
weak/moderately unstable column, and moderate shear. It would also
not be surprising if this system shifts to Saturday night if the
high pressure retrograde is slower than predicted.

The aforementioned low-level low pressure system looks to move in a
southeastern direction, which supports cooler temperatures with wrap
around moisture and northerly flow. This would work to increase non-
severe precipitation chances over the remainder weekend, but there
are a few reasons why this precipitation may not occur. For example,
we could get dry, southwesterly flow returning near the surface
which would cause more virga than precipitation.

On the very positive side, temperatures will be cooler! It looks
like the high temperatures will range from the upper 70s to lower
90s, with the warmest day being Friday. Overall, low temperatures
are stable, cooling into the mid 50s to mid 60s.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1015 PM MDT Mon Jul 15 2024

KGLD...VFR conditions are expected through the period. From taf
issuance through about 08z, scattered light showers and possibly
a thunderstorm will be near/over the terminal with perhaps some
erratic wind gusts to 30kts or so. From 09z-17z, winds
presently look to be light and variable. After 18z, light
northwest winds veer to the north by 21z, northeast by 00z then
from the east around 03z at speeds up to 10kts.

KMCK...VFR conditions are expected through the period. From taf
issuance through about 10z, scattered showers and perhaps a
thunderstorm will be near/over the terminal with perhaps some
gusty winds to 30kts or so. From 10z-23z, winds look to be light
and variable. After 00z, winds establish an easterly component
at speeds under 10kts.

&&

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

&&

$$

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