719
FXUS63 KGID 132111
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
411 PM CDT Wed Aug 13 2025

.KEY MESSAGES...

- Showers and thunderstorms may impact areas N of I-80 late
  tonight, particularly N of Hwy 92. Gusty winds may accompany
  the strongest activity, but overall severe risk is low.

- Main story for the rest of the week and through the upcoming
  weekend will be returning heat and humidity. Friday and
  Saturday look to feature the highest heat indices, possibly
  exceeding 105 degrees in some locations.

- Next meaningful rain chances don`t arrive until late Sunday or
  early next week, but even these chances are low at only 20-30%

&&

.DISCUSSION...
Issued at 355 PM CDT Wed Aug 13 2025

Pleasant late-summer day ongoing across the region with only
some fair weather cumulus across the sky. It`s warm in the mid
80s to lower 90s (pretty close to normal climatology), but
there`s a steady S-SE breeze to help with the seasonable heat
and humidity. We`re continuing to monitor the potential for
convection, probably in a weakening phase, to work into at least
N portions of the forecast area late tonight. This activity is
currently developing near/W of the Black Hills ahead of a
shortwave disturbance visible over central WY in recent WV
imagery. Timing of this wave, and recent HRRR runs, suggest a
05-08Z arrival into areas from around LXN to ODX. Unlike last
week, expect this nocturnal convection to be weakening thanks to
decreasing instability and overall weak shear. HREF MUCAPE is
only 1000-1250 J/kg after midnight, which is a far cry from the
3-4K J/kg with the damaging wind events late last week. Did
extend the PoPs slightly further S to include most of I-80
corridor, but this may not be enough given a veering LLJ. Rain
amounts should average 0.25-0.50" N of Hwy 92, but only T-0.10"
towards I-80 corridor.

Main focus for the remainder of the forecast is on increasing
heat and humidity, particularly for Friday and into the weekend,
when some locations may top 105 degrees on the heat indices.
Even tomorrow will be quite warm, though, as all areas should
at least see low to mid 90s. Far SW could get close to 100F.
Worth noting that there will be a strong Srly breeze, which
could help air temps "overachieve" (esp. SW zones), but could
also help mix out dew points a bit more than recently. This
could essentially be a "washout" when it comes to heat indices.

Temperatures should rise at least a few degrees on Friday (aided
by warmer lows), then another couple more on Saturday. Factoring
in seasonably high dew points (recent rainfall, Srly flow, and
strong ET) will bring heat indices to near Heat Advisory
criteria for both days. Fortunately, wet bulb globe temps will
be held in check thanks to the steady wind. Orientation of the
mid level ridge suggests the traditional "ring of fire" should
setup from the central High Plains into South Dakota - so
probably a lesser opportunity for cloud debris or outflow to
wreck things quite as much as late last week. All in all, looks
like an excellent weekend for those late summer activities that
involve water!

Ridge breaks down late Sunday into early next week, suggesting
some increase in shower/storm potential and somewhat "cooler"
temperatures. However, with climo values starting to slowly
fall, latest ensembles still keep us in above average
temperatures. We`re really only glanced by the upper trough, so
what rain chances we do have in the forecast are still low at
only 20-30%.


&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1245 PM CDT Wed Aug 13 2025

For KGRI/KEAR Airports:

Significant weather: Low level wind shear (LLWS) tonight.

VFR through the period. Quiet and low end breezy out of the SSE
through early evening. Overnight, expect a 40-45kt low level jet
to develop by midnight and persist through dawn. Given expected
sfc speeds around 8-10kt, this will create somewhat marginal
LLWS at the base of the inversion around 1000ft. Any LLWS will
quickly mix out Thu AM as sfc winds incr to 15-20kt, and gusts
approach 25-30kt by midday. Best potential for any
showers/storms tonight look to remain N of the terminals, so
held off on any PROB30 groups, for now. Confidence: Medium.

&&

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

&&

$$

DISCUSSION...Thies
AVIATION...Thies