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000
FXUS63 KGID 212330
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
630 PM CDT Sun Apr 21 2024

.KEY MESSAGES...

- A frontal boundary sliding south through the area Monday-
  Monday night will provide a focus for shower-storms, a few
  storms could be strong with small hail/gusty winds. Ahead of
  this front, gusty southwest winds are expected during the day
  on Monday.

- Near-critical fire weather conditions expected Tuesday
  afternoon over a larger portion of the forecast area, with
  widespread gusty northerly winds expected. Gusts near 30 MPH
  will be possible.

- A more active pattern is expected to develop mid-week on
  through the weekend. Strong-severe thunderstorms will be
  possible Thursday-Thursday night, and potentially into Friday-
  Friday night, depending on the timing of the main upper level
  low pressure system swinging through the Plains.

&&

.DISCUSSION...
Issued at 418 PM CDT Sun Apr 21 2024

Currently through tonight...

Though looking to end up near to just a touch below normal for
temps, today has been a pleasant end to the weekend. Aloft,
upper air and satellite data show continued northwesterly flow
in place across the area, set up between one disturbance
digging south through the Midwest and another sliding east just
north of the western US/Canadian border. Satellite imagery also
showing that outside a bit of fair weather cumulus clipping far
southwestern portions of the forecast area, skies are sunny. One
part of why it has been pleasant today has been thanks to the
surface pattern and lighter winds. A ridge axis extending north
from an area of high pressure centered over portions of western
KS/OK and northwest TX has been keeping winds over all
light...gradually turning more west then southwesterly with
time. Across far western portions of the forecast area are
starting to see a few more gusts closer to 20 MPH, which will
continue the rest of this afternoon. 3 PM temps range from the
mid 50s to right around 60 degrees.

Expecting the quiet conditions to continue on this evening into
the overnight hours, with a bit more mid-upper level cloud
cover working its way in, especially across northern portions of
the area. At the surface, models showing the ridge axis sliding
southeast of the area, while a frontal boundary will be
approaching from the northwest, driven by that upper level
disturbance moving into the Northern Rockies/central portions of
the US/Canadian border. This will tighten up the pressure
gradient across the area and bring increasing southerly winds
through the overnight hours...speeds near 15-20 MPH (and some
gusts near 30 MPH) are expected by sunrise Monday. The increased
southerly flow will help keep temps from dropping off like the
past couple of nights...forecast lows for tonight are in the
upper 30s to low 40s.

Monday through Wednesday...

Next chances for showers/thunderstorms returns to the forecast
late in the day Monday into Monday night. The above mentioned
upper level disturbance to our north-northwest at sunrise Monday
is expected to continue on a east-southeastward trek with time,
ending up in the MN by sunrise Tuesday. Main impact for the
daytime hours looks to be with the arrival of an accompanying
surface frontal boundary. Gusty southwesterly winds are expected
to develop during the morning hours ahead of the front,
impacting southeastern portions of the forecast area well into
the afternoon. Central and northwestern areas will have winds
switching to the northwest behind this front...model timing is
in generally decent agreement, with the front moving into the
west-northwest by midday and through the Tri-Cities area around
mid-afternoon. Gusts over 30 MPH are expected for those areas
ahead of the front, lighter along the boundary, then gusts
closer to 20 MPH expected behind the front. During the late
afternoon hours, can`t rule out some isolated precip developing
near the front...kept chances at 20 percent, as most models
actually keep things dry through 00Z. Having a daytime frontal
passage always makes for a tricky temperature
forecast...increased mixing along/ahead of the front helps temps
rise, cooler air behind keeps them from doing a whole lot.
Forecast highs tomorrow are in the low 70s in the far north-
northwest, mid 70s in the Tri-Cities, closer to/either side of
80 for locations ahead of the front longer into the day.

Better chances for showers/storms arrive Monday evening-
overnight, with chances anywhere in the 30-60 percent range.
Upper level lift is better as that disturbance moves further
into the region, and models also showing better convergence
along an increasing low-level jet nosing in from the southwest.
There is some uncertainties with just how much overall coverage
there is, but models are in decent agreement focusing the better
chances across portions of south central NE counties mainly
along/south of I-80. Not anticipating any of these storms being
severe, but can`t rule out a few being on the stronger
side...models are in good agreement showing meager instability
but strong deeper layer shear. Some small hail/gusty winds would
be the primary issues.

These precipitation chances are short-lived, expected to end by
sunrise Tuesday...with the rest of the day looking to be dry.
Main story for Tuesday is the reinforcing surface frontal
boundary pushed through the area, ushering in stronger north-
northwesterly winds. Area-wide speeds of 20-25 MPH and gusts
closer to 30 MPH are expected. Highs look to be a touch cooler,
in the mid 60s-near 70, with generally partly cloudy skies. With
dewpoints expected to mainly be in the 20s, even the cooler
temps will allow for relative humidity values to drop into the
low-mid 20s...and with the gusty winds...much of the area will
have the threat of near-critical fire weather conditions.

Late Tuesday night on into Wednesday brings the next chance for
precipitation to the area, again looking to be a fairly quick-
hitting chance. The overall upper air pattern is expected to be
westerly, as we sit with broad ridging across the central CONUS,
between troughing over the East Coast and a stronger system
working its way toward the CA coast. A weak embedded shortwave
disturbance moving out from the Central Rockies will bring
chances for showers to the forecast area, with models showing
instability focused to our south and west. Models also show some
uncertainty with coverage, and some even show us being missed
completely...so forecast chances are only 20 percent at this
point. Winds are expected to switch to the south, and again look
to be on the breezy side, as we sit between departing high
pressure to the east and gradually deepening low pressure to the
west. Strongest speeds look to be across areas west of Highway
281, where speeds of 20-25 MPH will be possible. Not expecting a
notable change in temperatures compared to Tuesday, with
Wednesday again in the mid 60s to right around 70 degrees.
Dewpoints rising into the 30s look to keep fire weather concerns
low.

Thursday on into the weekend...

The main focus for the latter portion of the forecast is on the
Thursday-Friday time frame, with the potential for more
widespread preciptiation chances and concern for strong/severe
storms. Models are in good agreement Wednesday night showing the
main upper level low pressure system moving onto the southern
CA coast, and by 12Z looks to be generally centered over the
CA/NV/AZ border area. The system slides east-northeast, ending
up roughly over the central- western CO/NM border by Thursday
evening. A few more differences arise Thursday night with exact
timing/track of this upper level low, which is in the western
NE/KS area by sunrise Friday. Increasing larger scale lift and
aided by a stronger low level will ramp up precipitation chances
Thursday-Thursday night, with widespread 60+ percent chances
currently in the forecast. The main focus for strong/severe
weather chances still looking to be across the southern half of
the forecast area...where models still have the better
instability (1500+ j/kg of MUCAPE) and SPC has the 15%
probabilities in the Day 5 Outlook. Though instability
diminishes some further north, deeper layer shear is roughly
30-40 kts area- wide, so there is some concern further north as
well.

The low itself looks to move out Friday-Friday night, and the
timing going to play a big part in severe weather potential
for our forecast area. Current timing of deterministic models
showing it being a close call whether or not the main surface
features and instability axis push far enough east to keep the
main concern out of our area...will be interesting to see how
models trend in the coming days.

Weekend precipitation chances are elevated for being out in Day
6-7, sitting in the 50-60 percent range for a good chunk of
the forecast area. These chances are driven by models showing
the potential for another fairly strong upper level low pressure
system swinging out through the Plains...that being said, there
are more differences in models with the track of this one, so
confidence suffers. ECMWF is more optimistic with precipitation
chances than the GFS...with both showing the first system Thur-
Fri pushing the brunt of instability out of the area to the
southeast.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 623 PM CDT Sun Apr 21 2024

High confidence (>90%) in VFR conditions through this period.
High clouds increase through the day Monday.

Southwest winds increase on Monday morning, and gusts of
20-30kts are expected into the afternoon (especially at GRI).
Winds then turn to the northwest/north late in the period as a
cold front moves through.

&&

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

&&

$$

DISCUSSION...ADP
AVIATION...Mangels