221
FXUS63 KGLD 180150
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
750 PM MDT Wed Jul 17 2024

.KEY MESSAGES...

- Thunderstorm chances continue through the end of the week with
  a risk for severe storms each day through Friday.

- Temperatures remaining near normal through next week.

- Locally heavy rainfall possible through Friday night.

&&

.UPDATE...
Issued at 750 PM MDT Wed Jul 17 2024

A large area of showers and thunderstorms over the northwest 1/3
of the area where precipitable water values run from 1.2-1.4
inches is forecast by the latest RAP/HRRR models to move to the
east and southeast very slowly (0-6km wind speeds within the
greatest confidence for rainfall under 10 mph) through perhaps
12 AM MDT (1 AM CDT). RAP model shows PWAT values increasing
perhaps up to 1.7 inches generally north of Interstate 70. After
midnight, some dissipation is forecast and could be a bit
sooner.

Increased and capped pops at 70% for now where confidence was
highest in shower/thunderstorm activity to continue over the
next several hours. Radar mosaic showing a slow decrease in
storm intensity and despite the high precipitable water values
and slow storm motions the overall threat for flash flooding
looks to remain low and somewhat isolated. Severe threat looks
to have diminished as well with some gusty winds and small hail
the primary hazards with the locally excessive rainfall.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 1205 PM MDT Wed Jul 17 2024

17Z Water vapor imagery and RAP analysis indicated CWA under
broad northwest flow with H5 ridge centered near the four
corners region with trough centered over the northeast CONUS. PV
analysis suggests at least 2 smaller disturbances moving over
top of ridge to the west. At the surface broad and light
easterly flow observed across area as surface ridge settles over
the area. With dewpoints in the low 60s, already seeing CU
fields develop, with storm initiation already occurring along
weak convergence zone near KLIC.

Primary short term concerns will focus on thunderstorm potential
each afternoon and evening through Friday.

As mentioned earlier, already seeing thunderstorm initiation on
subtle convergent zone along Palmer Divide and expect this to
continue on through the afternoon. While no major short wave
trough is apparent upstream, inhibition looks rather weak
allowing for several areas of thunderstorms to develop. The
first will likely be along convergent zone/south of Interstate
70 in eastern Colorado, with storms moving east southeast
through the afternoon hours. A second round of storms will
likely initiate over the higher terrain and merge into more of
an MCS in the evening hours. This will likely bring more
widespread storms as it moves east into Kansas. Have doubts
about how far east storms will make it as there is a rather
sharp gradient in available instability and have opted to be a
bit conservative on eastward progression. With instability
around 1000 J/KG and fairly straight hodographs expect a few
stronger storms early on, but think biggest threat will be
organized cold pools/ damaging wind gusts. High precipitable
water values, slow storm movement and high freezing levels
support a heavy rain threat as well, but best potential does not
seem to line up with where heavy rain has fallen recently.

On Thursday, sfc ridge retreats to the east as trough
strengthens over eastern Colorado. This will result in
increasing southerly winds as well as increasing temperatures.
While a similar upper level pattern will be in place during the
afternoon, H7 temperatures will be several degrees C warmer
than today resulting in stronger capping. Given the weak overall
forcing, confidence in thunderstorm development not as high as
today although threats will be similar to the last several days.
Pattern continues on Friday although afternoon forcing looks to
be stronger as weak cold front sweeps across the area. With
more focused forcing along front, looks like Friday evening may
be the best chance for rain across a large part of the area.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 1233 PM MDT Wed Jul 17 2024

Medium range models in general agreement with the overall large
scale pattern through the middle of next week as flow aloft
becomes more northerly and rather weak as H5 ridge remains
firmly in place across southwest CONUS and weak cut of low
develops over the Central Plains. While there is a bit of
uncertainty with exact track of this low, somewhat surprised
that it is pretty well accounted for in the GEFS mean showing at
least broad consensus between ensemble members. Net result will
be a cooler and cloudy weekend with showers possible through
Monday. With current data, does not appear to be a great severe
weather threat with weak shear and limited available
instability.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 415 PM MDT Wed Jul 17 2024

KGLD...VFR conditions are currently forecast through the period.
From taf issuance through about 06z, surface winds will be
erratic due to thunderstorms in the area but generally from the
south to southwest at speeds under 12kts. Outflow from nearby
thunderstorms could reach 35kts and given slow storm motions
visibilities could drop below VFR category due to heavy
rainfall. After 07z, light and variable winds become southerly
by late morning and increase in speed with gusts of 25 to 30kts.

KMCK...VFR conditions are currently forecast through the period.
An east to east-southeast wind up to 10kts is forecast from taf
issuance through 14z. From 15z-20z, southeast winds under 11kts
are forecast. After 21z, southeast winds gusting to 20kts or so
are forecast. Presently, convection appears to remain well west
and southwest of the terminal through the period. We will be
watching for any thunderstorms well northwest of the terminal
possibly making it toward the terminal late this evening.

&&

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

&&

$$

UPDATE...99
SHORT TERM...JRM
LONG TERM...JRM
AVIATION...99