729
FXUS63 KLBF 170002
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
702 PM CDT Thu May 16 2024

.KEY MESSAGES...

- Hot and dry tomorrow with highs approaching 90 and elevated/near
critical fire weather conditions

- Thunderstorms appearing more likely (60%+) Sunday and Monday with
severe weather possible, including all hazard types

- Brief stint of cooler/milder temps early in the week, then
  warming again by midweek with continued low end (<30%)
  moisture chances

&&

.SYNOPSIS...
Issued at 352 PM CDT Thu May 16 2024

The heart of an upper trough has moved downstream of the forecast
area today, with its axis roughly lining up with the Missouri River,
and placing western Nebraska into broad northwesterly flow aloft. A
closed upper low in the process of getting absorbed into the main
flow also lies to the southwest, currently centered over New Mexico.
Toward the surface, high pressure has gained control of the central
and northern Plains in the wake of a cool front. A weak boundary or
surface trough stretches along the High Plains, cutting across the
panhandle.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 352 PM CDT Thu May 16 2024

This evening into tonight... The surface high edges eastward,
transitioning low level flow to more return southwesterly. WV/IR
imagery indicate a couple rounds of mid/high clouds upstream, likely
associated with weak PV anomalies. A weak low level jet also
develops with guidance generally suggesting 30 kts at H85 in the
Sandhills. The combination of the strengthening southerly flow and a
thermal ridge will jump start the warm air advection scheme, shown by
6-7C rises over the last 24 hours. Went with a general blend for min
temps, which lines up near the median of the NBM envelope. Forecast
lows range from upper 40s panhandle to mid 50s north central.

Tomorrow and tomorrow night... Upper flow briefly becomes quasi-
zonal across Nebraska as the trough over the Great Lakes evens out
and a new trough digs upstream in the northern Rockies. A surface
low also spins up near the Black Hills and drags a cool front
through the Sandhills after dark. In the meantime, fair skies and
southwesterly low level flow will help accelerate warm air advection
further. Guidance is in good agreement with H85 temps ranging 20-25C
across the forecast area, which is a good 5C warmer than today.
Again used a general MAV/MET/ECS blend for max temps, which resulted
in a subtle upward trend over the previous forecast. While new
forecast highs sit in the upper 80s, these values correlate to the
lower end of the NBM envelope. Would not be surprised if later
forecasts need bumped up another degree or two, especially with
NAEFS ensembles suggesting 97%ile of climo. The cool front is
progged to cross overnight, primarily 06-12z. Questions remain
whether forcing can overcome marginal moisture to result in precip.
Left forecast dry as of now, but CAMS suggest iso/sct light rain
showers or sprinkles.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 352 PM CDT Thu May 16 2024

The weekend starts with northerly flow behind the cool front,
resulting in relief from Friday`s heat. Highs should generally stay
in the 70s, accompanied by nearly full sunshine. Attention quickly
turns to Sunday when the pattern turns much more active. Another
lobe in the large scale upper trough tilts the axis to negative,
transitioning the flow to southwesterly for the Plains. Southerly
low level flow is basically unimpeded from the Gulf, which helps to
push dew points well into the 50s. A lead mid-level shortwave
intersects a warm front passage early in the day and a dryline and
cool front later on. Parameters seem to be pulling together for a
severe weather scenario for western and north central Nebraska.
Abundant energy in the form of 1500+ j/kg MUCAPE and very steep mid-
level lapse rates (8+ C/km) combine with strong deep layer shear of
40+ kts. Preliminary forecast soundings resemble "loaded gun"
profiles, while hodographs indicate consistent veering in the low
levels. While convective evolution may be fuzzy, initial mode would
likely be supercellular for any development. Agree with the SPC
assessment of all hazard types are on the table. The bulk of the
forcing shifts east on Monday, but the post-frontal environment on
Monday could still comprise steep lapse rates and strong shear,
despite the fairly limited instability. Depending on precip coverage
during Sunday`s event and Monday`s new development, may need to
monitor excessive rainfall risk. The heart of the deep trough
crosses the central Plains on Tuesday, then a ridge gradually builds
in over the Rockies heading into midweek. Low end PoP persist into
Wednesday, while temps range from coolish Mon (60s north/70s south)
to seasonable by Wed (70s/maybe 80).

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 701 PM CDT Thu May 16 2024

Thunderstorms upstream coming off the Black Hills are moving
toward Nebraska but are expected to diminish with loss of
heating after sunset, so will not include any mention at KVTN
but will monitor closely and amend if needed.

Otherwise, VFR conditions will persist across central and
western Nebraska through the valid period. A low level jet will
become established southwest to northeast with the axis roughly
from KIML to KONL. Will include a mention of low level wind
shear at KLBF but expect KVTN will remain far enough from the
jet axis to necessitate a mention in the TAF. After daybreak
Friday once diurnal hearting becomes established, expect some
gusty conditions with southwest winds gusting to around 22kt.


&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SYNOPSIS...Snively
SHORT TERM...Snively
LONG TERM...Snively
AVIATION...MBS