Zero, Nebraska Weather Forecast Discussion

102
FXUS63 KGID 151150
AFDGID
Area Forecast Discussion
National Weather Service Hastings NE
650 AM CDT Mon Sep 15 2025
.KEY MESSAGES...
- Areas of dense fog possible this morning, and perhaps again
  Tuesday morning, for parts of the area.
- After a period of dry weather today and tonight, our next
  chance for thunderstorms arrives Tuesday evening and kicks off
  a rather active period that persists through Thursday night.
- There is a Marginal risk (level 1 of 5) for severe
  thunderstorms Tuesday PM - with the primary risks being
  isolated instances of 1-1.5" large hail, damaging wind gusts
  up to 60 MPH, and heavy rain.
- Above normal temperatures persist Today and Tuesday (highs in
  the mid to upper 80s) before cloudy, cooler, and occasionally
  wet weather settles in for the second half of the week.
&&
.DISCUSSION...
Issued at 420 AM CDT Mon Sep 15 2025
The potent shortwave trough responsible for last evening`s
thunderstorms can be seen on water vapor imagery spinning
north/northeast through the Dakotas into the Upper MS Valley
this morning, leaving widespread subsidence and clearing skies
in it`s wake early this morning. The clear skies, combined with
light and variable winds and very low temp/dew point spreads,
is promoting areas of stratus and fog development over the past
couple of hours. Various hi-res models have hinted at this
potential, but haven`t done a great job in the overall
depiction of location and coverage. Nonetheless, conditions
will remain favorable for fog to expand and worsen over the next
few hours, and it`s possible portions of the area may need a
Dense Fog Advisory for 1/4-1/2 mile visibilities through around
9-10AM. Any fog/stratus will burn off mid to late morning and
allow for another warm afternoon amidst light S winds and mostly
sunny skies. Could see a repeat scenario of AM fog/stratus then
warm afternoon temps on Tuesday, though the fog signal isn`t
quite as strong in recent model guidance - likely owing to
slightly stronger near-surface flow late tonight.
Changes begin to take shape late Tuesday afternoon into the
evening hours as a cold front approaches from the NW. Multiple
models show convection initially developing along/ahead of this
front over the Nebraska Sandhills region during the late
afternoon, before shifting E/SE during the evening and overnight
hours. Overall, tend to think convection could take an evolution
very similar to that of last night in which moderate instability
and modest (but largely boundary parallel) shear promotes
upscale growth of scattered convection into a loosely organized
line and produces a few pockets of strong to marginally severe
activity. Seasonably high PWATs and at least some localized
training of stronger cores could also lead to spotty heavy rain
of 2-3" in short amount of time. Highest storm chances/coverage
currently favors areas N/W of the Tri-Cities given current
timing of the front - with gradually decreasing
organization/intensity by and esp after midnight Tuesday night.
Complex/messy upper trough structure will shift into the
central/northern Plains for the second half of the week and
bring multiple additional chances for showers/storms to much of
the region. While specific details on timing and coverage of
highest chances remains uncertain owing to the aforementioned
complex trough structure - seems pretty safe to say esp. the
Wed-Thu time frame will be much cooler, cloudier, and wet
compared to the start of the week. Latest deterministic EC, for
example, even keeps the active weather going into the weekend as
multiple vort maxima interact with one another within the
broader trough, potentially, at times, creating a bit of a
Fujiwara type effect. Throw in the possibility for one or more
MCVs and things could get even messier. Latest NBM drops highs
into the 70s for Wed, then upper 60s to mid 70s for Thu-Fri,
though could easily see these trending cooler if timing/coverage
of rain favors any portion of the late morning through afternoon
time frames. Additional severe weather chances are not zero
(particularly on Wednesday), though modest mid level lapse rates
and deep layer shear argue against anything too intense.
Off and on rain chances continue Friday and into the weekend,
but model agreement isn`t as good and it`ll really just depend
on how/if the upper trough evolves over the Dakotas into Upper
MS Valley region. With that said, Friday chances appear to be a
bit higher (30-40%) compared to Saturday and Sunday (10-30%).
Temperatures could moderate some for the weekend, but still
expect mainly 70s to lower 80s for highs and 50s for lows.
&&
.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 649 AM CDT Mon Sep 15 2025
For KGRI/KEAR Airports:
Today: Tricky TAF forecast in the very near term as just about
any combination of VFR to LIFR CIGs and VSBYs will be possible
for another 1-2 hours due to shallow stratus/fog. Fortunately,
since it does appear to be quite shallow on satellite, webcams,
and forecast soundings, should see pretty quick improvement and
dissipation in the 14-15Z time frame...so only TEMPO-ed the
reasonable worst case scenarios for the 12-14Z time frame. GRI
in particular looks to be right on the edge of a stratus bank as
of this writing. The rest of the daytime hours should be VFR
with little to no cloud cover, and lgt and variable winds
becoming southerly at 7-12kt.
Tonight: Primarily VFR conditions expected, though can`t
completely rule out another round of shallow ground fog late
tonight. Models aren`t as aggressive as early this morning, so
only went with 6SM BR for now to hint at the potential. Winds
will go light at dusk and remain southerly or variable.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
DISCUSSION...Thies
AVIATION...Thies

NWS GID Office Area Forecast Discussion