542
FXUS63 KGLD 210851
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
251 AM MDT Fri Jun 21 2024

.KEY MESSAGES...

- Continued very windy Friday with 20%-30% chances for afternoon
  and evening thunderstorms, some of which could become severe.

- Weekend looks to remain hot with highs in the 90s. Could be a
  few severe thunderstorms Sunday afternoon/evening.

- Hottest temperatures of the period Monday/Tuesday. Heat index
  values of 100-105 degrees east of Highway 25.

- Not as hot (highs in the 90s) Wednesday/Thursday with better
  chances (20%-40%) for thunderstorms moving through the area
  from the west during the late afternoon to overnight hours.

&&

.UPDATE...
Issued at 647 PM MDT Thu Jun 20 2024

Watching cluster of storms draped from roughly the Denver
Airport into the the Nebraska panhandle. The storms are cold
pooling to the ENE and may clip NW portions of Yuma county.
Overall not much change to the forecast.

Did bump up winds from 23-02Z Friday evening as the GFS has been
consistently showing an 8mb pressure rise and 40-45 knot winds
in the 850-800mb range, which if this does come to fruition
would not be difficult to mix down with pressure rises of that
magnitude. RAP and NAM however show 3-4mb pressure rises in the
same period and no where near that magnitude of winds in the
same layer. Previous experience does lean more towards the GFS
solution especially when it comes to winds so am leaning
towards that solution at this time, but is plausible that winds
remain in the 30-35 knot range if the RAP and NAM where to
verify.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 115 PM MDT Thu Jun 20 2024

Tonight...a small area of moisture in the 700-500mb layer is
forecast to move off the Palmer Divide area and into the northwest
corner of the forecast area (from near Flagler to Wray north) early
this evening, supporting 20%-30% chances for showers and
thunderstorms. The primary hazards will be outflow wind gusts to 60
mph and hail to the size of quarters. Otherwise, it should generally
be clear with low temperatures in the lower 60s to around 70. Breezy
to windy southerly winds will continue generally west of Highway 25.

Friday-Friday night...a monsoonal type pattern sets up with an upper
trough to our west and ridge centered over the southeast states.
Unfortunately, moisture from Mexico is skirted to the south of the
area (oriented from southwest Kansas to northeast Kansas). There is
a bit more moisture in the 700-500mb layer compared to 24 hours ago
that moves into the northwest half of the area from the Raton ridge
area, supporting 20%-30% chances for showers and thunderstorms north
of a line from Kit Carson to Colby and Norton from around noon MDT
to midnight MDT. A few thunderstorms are possible with hail and
strong wind gusts the primary hazards. It will be windy once again
with southerly winds gusting in the 35 to 45 mph range during the
day, steadily decreasing overnight while veering to the southwest to
northwest.

Saturday-Saturday night...500mb flow shifts from southwest flow
aloft to zonal with troughing to our north and an elongated ridge to
our south. Presently, dry weather is forecast. There could be some
isolated flirting with the northwest corner of Yuma and Cheyenne
counties (Colorado) in the 23z-02z timeframe as some mid level
moisture moves off the Cheyenne Ridge and Palmer Divide into those
areas. High temperatures are forecast to be in the upper 80s to
middle 90s with low temperatures in the 60s.

Sunday-Sunday night...broad upper level ridging strengthens over the
area. High temperatures continue to rise with readings in the middle
to upper 90s. Low temperatures are forecast to be in the 60s. It
appears from the GFS/NAM models show a plume of moisture in the 700-
500mb layer moves into parts of the forecast area from south central
Colorado, supporting at least a 20% chances for afternoon
thunderstorms for quite a bit of the area. As a result, I`ve
expanded the areal coverage of possibility from what the NBM loaded.
Any thunderstorm activity quickly dissipates in the early evening
hours. High temperatures are forecast to be in the 95 to 100 degree
range with low temperatures in the 60s.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 250 AM MDT Fri Jun 21 2024

Mon-Tue: Long range guidance indicates that the Tri-State area
will be situated on the northern periphery of a broad, west-
east elongated ridge (centered over the Desert Southwest,
Southern Plains and Lower MS River Valley).. at the southern
fringe of the mid-latitude westerlies. Above average
temperatures are likely. In such a regime, precipitation chances
will largely be tied to the development (and downstream
propagation) of diurnal convection emanating from the Colorado
Front Range and Palmer Divide.. augmented (perhaps) by small
amplitude waves on the southern fringe of the westerlies.

Wed-Fri: Long range guidance indicates that the aforementioned
upper ridge will consolidate/amplify over the Desert Southwest
and extend northward to the 4-Corners and central Rockies (Wed-
Thu).. then flatten and regress southward to the Desert
Southwest/Southern Plains (Fri).. as an upper level trough
progresses eastward ashore the Pacific Coast and cyclonic flow
aloft envelopes the Intermountain West. Above average
temperatures are apt to persist. In such a regime, precipitation
chances /convective development/ will highly depend upon the
evolution of the ridge. -- At present -- guidance suggests that
the magnitude, position and orientation of the ridge will be
such that (1) synoptic subsidence may largely suppress diurnal
convective development along the Colorado Front Range/Palmer
Divide and (2) that low-level forcing/moisture may be
insufficient for in-situ convective development on adjacent
portions of the High Plains (i.e. northwest KS). In this
pattern, at this range.. convective forecast confidence is below
average.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1007 PM MDT Thu Jun 20 2024

VFR conditions are currently forecasted for the majority of the
TAF period. Am watching for the potential for some storms
Friday afternoon/evening for each terminal so have included in a
Prob30 to account for this. Not much has changed since the 00Z
issuance as breezy to gusty southerly winds and LLWS will be the
primary story for each terminal.KMCK winds will remain around
10 knots through the night due to the proximity from a surface
low across east Colorado.

Ongoing showers and storms and an outflow boundary from
convection across northeast Colorado will need to be watched as
the convection has overperformed due to longevity. If the
outflow boundary can reach each terminal then a brief wind
shift to NW winds may occur but will include a tempo as it may
affect the terminals an hour or two after TAF issuance.

&&

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

&&

$$

UPDATE...Trigg
SHORT TERM...99
LONG TERM...Vincent
AVIATION...Trigg