Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 220934
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
434 AM CDT Fri Mar 22 2024

.KEY MESSAGES...

- Can`t rule out some light precipitation late tonight into
  Saturday, but by far the main concern for precipitation comes
  Sunday through Monday night. Anything from strong-severe
  thunderstorms to accumulating snowfall will be possible in the
  forecast area.

- Sunday afternoon and evening bring increased chances for
  thunderstorms, with the potential for some to be severe. Areas
  south of Interstate 80 to roughly the NE/KS state line are
  included in the SPC Day 3 Marginal Risk area, while north
  central Kansas is included in the Slight Risk area. Large hail
  and damaging winds look to be the primary threats.

- Sunday night into Monday, colder air building in will be
  switching precipitation over to snow...but some questions
  remain with the timing of that switch over, and just how much
  snow we see. GFS/ECMWF ensemble keep the best potential of at
  least 3 inches snow in our forecast area around 30 percent,
  confined to far north-northwest areas.

- Gusty winds are a concern both Sunday and Monday. On Sunday,
  winds remain south-southeasterly, with gusts over 30 MPH
  likely for many locations. Sunday night into Monday, as the
  main surface low/cold front slide through and east of the
  area, strong northwest winds spread across the area. Gusts
  over 50 MPH are not out of the question, especially for areas
  west of Highway 281. These winds, combined with any snowfall,
  could result in hazardous conditions. Still plenty of details
  to iron out in the coming days.

&&

.DISCUSSION...
Issued at 425 AM CDT Fri Mar 22 2024

Currently...

For most of the forecast area, conditions so far tonight/early
this morning have been on the quiet side. A few
sprinkles/showers have clipped far northern portions of the
area, likely only trace amounts to this point. Upper air and
satellite data show a shortwave disturbance embedded in overall
west-northwesterly flow making its way through the Dakotas early
this morning...while elsewhere across the CONUS, broad ridging
is set up over much of the west, and an area of low pressure is
sliding east across eastern TX. This shortwave disturbance over
the Dakotas and increased lift along the nose of a LLJ is
driving the ongoing precipitation, which has largely missed our
coverage area, and currently is focused over east- northeastern
NE. Kept a 20 percent chance of rain going through the rest of
these early morning hours mainly across northeastern counties.
Though colder air is advecting into the area, precipitation
looks like it`ll be out before the sub-freezing temps become
more of an issue. The colder air building in is accompanying a
surface cold front being pushed south through the region by that
northern upper level disturbance, and at 3AM has made it about
a third of the way through the area. 3AM temperatures range from
the mid 30s in the north to near 50 in the far southeast.

Today through the day on Saturday...

As that upper level disturbance continues sliding east this
morning, that surface cold front sinks further south, and by
mid-morning should be south of the forecast area. While chances
for precipitation wane and the rest of today remains dry, this
cold front will usher in gusty northerly winds, which are
expected to linger much of the day. The best potential for gusts
near 30 MPH look to be through at least early afternoon,
gradually tapering off from NW to SE through the rest of the
day. Skies look to be partly cloudy to mostly sunny today, but
did lower highs for today a few degrees with the colder air
advecting in...forecast highs are in the low-mid 40s in the
north to low-mid 50s in the south.

For most of the forecast area, this evening/overnight and on
into Saturday look to stay dry. Models show another, more
subtle shortwave disturbance sliding across the region, bringing
the potential for some spotty light preciptiation. This looks
to be a roughly 09-15Z time frame issue...if it happens at all.
Confidence is not high, as models vary from nothing at all to
any spot east of HWY 281 and into north central KS could see
light precipitation. Kept chances at 20 percent for the most
part, but the areal coverage of those chances is likely too
broad. With temperatures tonight expected to drop into the 20s,
any precipitation that falls looks to be snow, but anything more
than a dusting is currently not expected. Winds tonight into
Saturday morning are expected to turn more easterly and be
lighter, closer to 10-15 MPH. As surface low pressure deepens
over CO ahead of the next storm system, winds are expected to
increase in speed during the day Saturday, turning more south-
southeasterly. Gusts near 30 MPH will again be possible,
especially for the western half of the coverage area. Highs on
Saturday are currently not expected to be notably different,
still in the 40s-50s, but models do show a warmer airmass
starting to work its way back into the region...just vary on its
timing.

Sunday and Monday...

By Saturday evening, models show an upper level low pressure
system moving onto the northern West Coast, digging further
south and becoming a little less organized as it pushes east
into the Rockies. This system evolution and eventual passage
through the Plains will be what drives things Saturday night on
through Monday night, the most active period of this 7-day
forecast period.

The first round of precipitation looks to come Saturday night,
with models showing a shortwave disturbance swinging east-
northeast through the region and increased convergence/lift
along a 50+kt LLJ nosing into/through the local area. Some
models also showing the potential for a bit of elevated
instability to work its way north into the area, bringing the
chance for thunderstorms (looks to be non-severe at this point),
mainly to portions of the area along/south of I-80 into north
central KS. Across northern portions of the area, there is some
uncertainty with precipitation type, and whether or not any
wintry mix/snow at least briefly makes an appearance...but most
models support the warmer air advecting in pushing the sub-
freezing temps/wintry precip north of the area as the better
precipitation chances expand.

For Sunday and Monday, there are still a lot of finer details to
iron out, so confidence is not the highest, but the forecast
area will have the potential to see anything from strong-severe
thunderstorms to accumulating snowfall.

On Sunday, models show that this upper level system which had
moved onto the West Coast more organized splits up...with one
lobe of energy continuing to dig south into the Desert SW, while
the rest continues west through the Rockies. During the
afternoon/evening hours on Sunday, the next shortwave trough is
expected to emerge out onto the Plains, bring the next chance
for thunderstorms. Current forecast/NBM-driven precipitation
chances are plenty generous during the day on Sunday, there may
be more of a lull between the morning activity and later that
afternoon, something that will be more refined in the coming
days. Sunday looks to be a windy day, as we`ll be sitting east
of a surface low deepening over eastern CO. South- southeasterly
winds gusting over 30 MPH currently look likely for most of the
area. Questions remain with how much moisture can be pulled
north into the area ahead of the surface dry line through the
afternoon, with models struggling to get the 50 deg. dewpoint
line too far north into the forecast area...and there are
differences with the timing/placement of the sfc dry line, with
some models keeping the main axis of better instability just
west of the forecast area. Afternoon/evening thunderstorms and
better chances for strong-severe storms are expected to fire
along that surface dry line...and with at least some models
showing it moving into our area, can`t argue with the placement
of the SPC Day 3 Slight Risk area across our south. Current
thinking is this would be a mainly hail/wind threat for us, as
better low level moisture looks to be just to our south...but
will see how models trend the next couple of days.

So while Sunday into at least the evening hours Sunday are
expected to have precipitation type remain liquid...the
concern for colder air building in and a switch over to snow
will be increasing Sunday night into Monday. Models are in
generally good agreement showing this upper level system not
exactly in a big hurry to move out of the area, but do still
have some difference with how it evolves as it moves
thorugh...how long it stays a more organized low (or redevelops
into one later Monday), how quickly it weakens, the exact
location of a stronger, narrow band of heavier snow. At this
point, models (deterministic and ensemble) continue to generally
agree with the heavier snow remaining north-northwest of our
forecast area, but some snow accumulation is expected here as
well...mainly NNW of the Tri-Cities. Still some uncertainties
with amounts, but a couple inches is not out of the question in
our NNW. Precipitation is currently forecast to end by sunrise
Tuesday.

As mentioned above, Sunday is expected to have gusty southerly
winds ahead of the deepening surface low...but there is also
the potential for strong winds Sunday night-Monday morning.
Models showing this wound-up surface low to trek trough the
southeastern portions of the forecast area, with strong
northwest winds building in with the cold front as it pushes to
our east. This is especially a concern over the western half of
the forecast area, where models show a corridor of stronger
winds aloft. While the timing being at night-early morning isn`t
ideal for mixing into those stronger winds, gusts over 50 MPH
are not out of the question. So these winds, added to a switch
over to snow Sunday night-Monday morning, leads to increased
concern for hazardous wintry conditions...but with questions
lingering with timing of the colder air/switch, it`s hard to
have a ton of confidence at this point...but is a period worth
keeping an eye on.

Tuesday and on...

The forecast dries back out for Tuesday and Wednesday...with the
next preciptiation chances working back into the area late
Thursday/Thursday night. After high temperatures going from the
50s-60s on Sunday down into the 30s on Monday...things
gradually rebound back into the 40s-50s by Wednesday and 50s-60s
for Thursday.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1214 AM CDT Fri Mar 22 2024

Can`t rule out some marginal LLWS for the first couple hours of
this TAF period, before a cold front pushes south through the
area, ushering in gusty northerly winds for most of the rest of
the period. There are some differences between models with
ceilings, especially as we get closer to sunrise, but can`t
totally rule out at least a brief period of MVFR ceilings, so
did insert a TEMPO group for that. Otherwise VFR ceilings are
currently expected. Gusts around 30 MPH will be possible later
tonight, with mention going through the mid-afternoon hours,
before tapering off to closer to 10-15 MPH through the end of
the period and turning more to the northeast.

&&

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

&&

$$

DISCUSSION...ADP
AVIATION...ADP


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