188
FXUS63 KGID 280611
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
111 AM CDT Sun Apr 28 2024

...Aviation Update...

.KEY MESSAGES...

- Although isolated/scattered storms will occur Sunday daytime,
  the track of the primary surface low pressure center (and
  attendant cold front) looks to skirt south and east of our
  CWA. As a result, we currently look to largely be spared a
  severe storm risk...although a few storms with up to around 1"
  size hail cannot be ruled out.

- Following a break in thunderstorm chances mainly Sun night-Mon
  night, various low-confidence chances return especially Tues-
  Thurs as an overall-active pattern continues.

- Temperature-wise: nothing unusual for late-April/early-May
  whatsoever, with highs most days somewhere in the 60s/70s and
  lows most nights in the 40s/50s. However, one of the chillier
  nights with more widespread mid-upper 30s is Sun night-Mon AM,
  and some frost cannot be ruled out, or even a sub-freezing
  reading here or there, especially north/west of the Tri
  Cities.

&&

.DISCUSSION...
Issued at 308 PM CDT Sat Apr 27 2024

Currently, surface low pressure was situated over the panhandle of
Oklahoma with a warm front extending northeast into northeast KS/
southeast NE. A cool northeast surface flow was situated over the
forecast area but with a warmer southerly flow approaching Mitchell,
Osborne and Jewell counties in our far southeast CWA. Convection to
the north of the warm front has lifted into far southern
Mitchell and is approaching southeast portions of Osborne
county.

Late this afternoon and tonight the aforementioned warm front will
try to lift northward this afternoon but may not make much progress
as current convection over the southern CWA possibly pushes the warm
front south a bit. There is growing evidence that convection lifting
northward this afternoon will be more isolated or perhaps scattered
in nature as it lifts into Nebraska and towards the I-80 corridor. A
majority of the CAMS are not that robust with convection as it lifts
into Nebraska. The strongest cells remain in Kansas, closer to the
warm front. With that said, significant strong bulk shear remains
over the entire CWA, and MU CAPE continues to inch northward into
south central/southeast NE, keeping the threat of elevated strong to
severe convection a possibility. As we go through the afternoon we
may continue to pare down the pops a bit. For now they are a blend
of our latest NBM pops with the consensus of short term guidance. If
the warm front position does remain farther south, this may also
limit the potential for tornadic storms, but again with the surface
low remaining in the vicinity, the potential will remain, especially
over our southeast Kansas counties and possibly into the southern
tier counties of Nebraska.

As was mentioned in the previous discussion there may be a bit of a
lull between the the current round of convection lifting north into
the forecast area, and another round later tonight as the surface
and upper level lows both lift north and east into the Plains.
However, there may not be a lull in some areas as convection also is
rapidly developing over west central Kansas and will be lifting into
our southern CWA shortly. It`s possible we see convection lingering
over Kansas and our southern NE counties into the evening, with
another wave lifting northeast through a good portion of the CWA
later tonight as the aforementioned upper low lifts into the local
area increasing forcing for ascent throughout the CWA. Either way,
it looks to be a busy afternoon and evening across the areas, and
especially over Kansas this afternoon. SPC has just issued a severe
thunderstorms watch that includes all of our Kansas counties
through 9 PM this evening.

Sunday the surface low tracks off to our east and the upper
level low lifts northward just to our west. This should make
for a cloudy and cool day with numerous showers and isolated to
scattered thunderstorms through the morning and possibly into
the afternoon, before tapering off Sunday night. Our far
southeast counties will remain near but just outside of the
marginal risk for severe storms.

Finally by Sunday night we begin to clear out from southwest to
northeast. Will need to monitor the western and northern
counties for possible freezing temperatures. Currently, we do
have a mention of frost and the latest NBM guidance is depicting
some temperatures below freezing west and north of the Tri
Cities.

For the most part, the upcoming work week remains fairly active,
although Monday may bring us a bit of a break in convection. By
Tuesday, we see a broad upper level trough develop over the
northwest U.S. into the northern Plains. An initial cold front
moving through the central Plains on Tuesday may bring isolated to
scattered thunderstorms to the area, but at this time the greatest
instability and higher moisture remains south and east of the
forecast area.

In the Wednesday through Friday timeframe another upper level low
tracks through the aforementioned mean upper level trough. With a
broad southwest upper flow over the area isolated to scattered
showers and and a few thunderstorms are possible on Wednesday, with
better chances for more widespread showers and thunderstorms as
another surface low develops in the lee of the Colorado Rockies and
the upper level low tracks across the central/northern Rockies. This
could bring us our next chance for strong to severe storms,
especially over our Kansas counties. Then by late Thursday
uncertainty increase in how the upper low evolves as we head into
the weekend. Perhaps we have a dry Friday or it`s possible we see
showers and a few thunderstorms. Currently the NBM not really
resolving this, leaving us with a broadbrush of slight chance to
chance pops late in the work week and early next weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 111 AM CDT Sun Apr 28 2024

- General overview for KGRI/KEAR:
The vast majority of the period will likely feature sub-VFR
ceiling (as lo as IFR and perhaps LIFR for a time), with a
period of sub- VFR visibility in fog also possible for several
hours this morning primarily at KGRI. Precipitation-wise,
isolated/scattered showers will continue to roam the general
area mainly through these first 12 hours, with a few weak
thunderstorms not out of the question. Wind-wise, no big
concerns, but moderately-breezy speeds with gusts at least into
the 20-25KT range will occur at various times, as direction
shifts from north-northeasterly to west-northwesterly as a low
pressure center passes off to the south-through-east.

- Ceiling/visibility and rain/thunderstorm details:
Ceiling:
Right out of the gate, a mix of IFR/MVFR ceiling is present, and
one of these categories will likely prevail through the vast
majority of the period, with perhaps at least a few hours of
LIFR also possible particularly in the 09-15Z time frame (not
currently reflected as prevailing, however). Confidence is not
overly-high regarding exactly when sub-VFR ceiling will scatter
out and/or vacate the area, but for now have very tentatively
aimed 03Z KEAR/04Z KGRI.

Visibility:
Although any passing showers/thunderstorms could briefly result
in sub-VFR visibility, the overall-greater concern is the
possibility for a period of fog to settle into particularly KGRI
during at least some part of the 09-15Z time frame. For now have
aimed for prevailing MVFR, but it could end up worse than this
for a time (adjustments quite possible here).

Rain/thunderstorms:
Mainly spotty (isolated to scattered) rain showers and possibly
a few weak thunderstorms remain "fair game" through especially
these first 12 hours. Expected coverage/duration do not warrant
any prevailing/TEMPO groups at this time, so have gone with a
generic "vicinity shower" (VCSH) and will amend to include
thunder if near-term observations support it.

- Winds:
As a surface low pressure system gradually tracks from well to
the south of the area to east of the area, direction will swing
around from north-northeasterly early this morning, to
northwesterly during the day, to more westerly Sunday evening.
Although there will be a lull in speeds a few hours either side
of sunrise and again very late in the period, the majority of
the period will feature sustained speeds at least 10-15KT/gusts
at least 15-22KT.

&&

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

&&

$$

DISCUSSION...TWH/WFO Bismarck
AVIATION...Pfannkuch