254
FXUS63 KGID 110006
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
706 PM CDT Mon Jun 10 2024

...Aviation Update...

.KEY MESSAGES...

- Potential remains for a few isolated/scattered thunderstorms
  to slide east into the area late this evening/tonight. Main
  chances are west of Highway 281. Storms are not expected to be
  severe. Lingering isolated activity is possible into Tuesday
  as a weakening frontal boundary sinks south through the area.

- The heat cranks up Wednesday and Thursday. More widespread
  Heat Index values of mid 90s-near 100 possible on Wednesday,
  with a smaller area of 100-105 degree values possible on
  Thursday (mainly along/south of the NE/KS state line).

- Better chances for storms return late in the week into the
  weekend, with the best chances (40-60 percent) currently in
  the Friday evening-Saturday night time frame.

&&

.DISCUSSION...
Issued at 424 PM CDT Mon Jun 10 2024

Currently through Tuesday...

It`s been another overall pleasant day across the area, with
temperatures this afternoon not too far from normal for this
time of year, and outside of some upper level cirrus, skies
have been sunny. In the upper levels, the area sits under weak
west-northwesterly flow, thanks to a ridge axis extending
northeastward through much of the Plains, set up between
shortwave troughing moving through the High Plains and larger-
scale troughing over the East Coast. At the surface, winds to
start the day were light/variable thanks to high pressure over
the region...but have turned southerly through the day as that
high slides east and low pressure/frontal boundary are shifting
through the High Plains. Across roughly the western half of the
forecast area, sitting under a bit tighter pressure gradient,
gusts at times have reach the 20-25 MPH range. Hasn`t been any
surprises with temps this afternoon, at 3PM sitting in the upper
70s to low 80s...with dewpoints still in the 40s-low 50s
keeping humidity down.

As expected, thunderstorms have fired off to our west along the
surface frontal boundary as that upper level trough axis has
moved in...and this activity is the main forecast concern as
we get into tonight and Tuesday. Overall, there hasn`t been any
notable changes to the forecast. Models continue to show a
weakening trend in activity as it gets shifts east, with the
better upper level and low- level jet forcing, along with
instability, remaining north and/or west of the forecast area.
Because there still is some uncertainty with the coverage of
activity as it slides east, kept precipitation chances in the
40-50 percent range in far WNW areas, dropping off pretty
quickly to 20 percent chances further SE. This activity is not
expected to be severe.

As we get into Tuesday, have 20 percent chances lingering
through the day. These chances will be tied to the surface
frontal boundary gradually sinking south through the forecast
area, with models showing it weakening/becoming more diffuse as
the day passes as it continues to lose any upper level push.
Expect any activity to be fairly isolated/scattered in nature, a
few models show things being quiet after mid-late morning, so
there is some uncertainties with timing. Outside of lingering
precip chances, the main impact from this front is ushering in
light/variable to more NNErly winds to portions of the area.
Temperatures aren`t affected, as highs are expected to climb
into the mid-upper 80s.

Wednesday and Thursday/Thu Night...

The first noticeable days of heat of the year are expected to
arrive area-wide Wednesday and Thursday. Models showing upper
level ridging trying to build its way back north through the
Plains, but various disturbances around keep it from getting too
strong. The forecast for Wednesday on through the daytime on
Thursday is currently dry. Because the ridging is not overly
strong, there will be the potential for a disturbance to get in
close proximity late in the day Wed-Wed evening...but along with
the lower level air mass warming, so does the mid-levels, which
increases capping across the area. Most models keep better
precipitation chances just off to our NNE. At the surface,
potential is there for breezy southerly winds on Wednesday, with
that upper level wave to our north looking to push a frontal
boundary south into the area Thu/Thu evening...which will be the
focus of better thunderstorm chances, continuing on into the
overnight hours. Depending how things trend, activity along that
boundary could have the potential to be strong/severe.

As far as the heat goes, current forecast has Wednesday with
more widespread hot temperatures, then Thursday having the
potential to be a touch hotter...but focused over a smaller
area. Wednesday sits under increased southerly flow and
widespread 850mb temps increasing into the mid-20C range...with
afternoon high temps in the mid-upper 90s, and with current
forecast dewpoints resulting in Heat Index values near 100 in a
handful of spots scattered across the forecast area. On
Thursday, areas north of that frontal boundary have more
northerly winds and cooler temps, but locations near/ahead of
that front (areas near/south of the state line) could have highs
right at/just above 100, and Heat Index values potentially in
the 100-105 degree range.

Friday on through the weekend...

Periodic thunderstorm chances continue in the forecast Friday on
into Monday, with the overall best chances still focused in the
late day Friday through Friday night time frame (40-60
percent)...but decent chances (30-50 percent) are also present
into Saturday. Models showing the upper level ridge axis sliding
east of the forecast area, with the potential for a stronger
upper level disturbance to move into the area...this time from
the Desert SW as opposed to previous ones being the NWrly
flow/ridge-runner variety. Plenty of details to iron out with
the timing of this system, with both the onset and just how
quickly it pushes through...as that ridge axis keeps its
progress on the slower side. Hard to have a lot of confidence in
the details, but the Friday evening-Saturday night is the best
chances for precip through this entire 7-day forecast period.
The lower confidence extends into temperatures for this time-
frame, which currently sit in the 80s/90s, but precipitation
could throw some wrenches in that.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 705 PM CDT Mon Jun 10 2024

For KGRI/KEAR Airports:
- General overview:
This is a high-confidence forecast regarding VFR
ceiling/visibility, with any potential ceiling expected to be
near-to-above 10K ft. (primarily overnight). Precipitation-wise,
the vast majority of the period will surely be dry, but a
passing shower/weak thunderstorm cannot be ruled out late
tonight-early Tues AM. Assuming no convective outflow comes
into play, winds will not be much of an issue, with sustained
speeds mainly at-or-below 10KT once any residual afternoon
gustiness wears off this evening.

- Shower/thunderstorm details:
Have maintained the previously-introduced mention of generic
"vicinity shower" (VCSH), but tweaked the time frame to 07-13Z.
At any point during that window, a passing shower/weak
thunderstorm is not out of the question, but felt confidence in
thunder occurrence was not quite high enough to justify formal
TS mention.

- Wind details:
Assuming any of the possible/aforementioned convection during
the 07-13Z time frame does not throw out any "sneaky"
outflow/gustiness, winds should not be much of an issue. Right
out of the gate this evening, there could be a few more hours of
southerly gusts 15+KT. However, by/beyond sunset sustained
speeds should average at-or-below 10KT, with direction trending
a bit more southwesterly late in the night. During the latter
half of the period Tuesday daytime, a weak front will settle
into the area, turning direction more northerly for a time but
also bringing some uncertainty in "exact" wind direction
especially during the afternoon. As a result, for now have just
indicated a basic light/variable group (VRB06KT) late in the
period, as no matter direction, speeds should be fairly light.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.

&&

$$

DISCUSSION...Pfannkuch
AVIATION...ADP