181
FXUS63 KLBF 132035
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
335 PM CDT Mon May 13 2024

.KEY MESSAGES...

- Thunderstorms return to the area tomorrow afternoon into
  Wednesday ahead of a frontal boundary, some of which could be
  strong.

-  Warm and drier conditions then round out the workweek, with
   highs well above average (mid/upper 80s) Friday and Saturday.

-  More active weather (thunderstorms and precipitation) could
   return by late weekend and persist into early next week,
   though confidence in this remains low for now.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 335 PM CDT Mon May 13 2024

Currently, the area sits in a post-frontal airmass, on the
northwestern periphery of an upper low centered over eastern
KS/western MO. Temperatures have climbed into the 70s across the
area, with diurnal cumulus development noted across much of western
and north central Nebraska.

Lapse rates remain steep enough in the lowest few kilometers aloft
to squeeze out at least some CAPE across the area this afternoon.
That said, very nebulous surface features and limited convergence
has largely precluded any widely isolated thunderstorm development
thus far. Cannot completely rule out a thunderstorm across north
central Nebraska (where an outflow boundary is sliding westward into
Holt/Wheeler counties as I type this) though confidence is too low
to add precipitation mention for now. By tonight, a quick moving
shortwave will begin to push eastward across WY, with an associated
surface low gradually deepening across eastern WY overnight. This
will transition low level flow back southward, and lead to
increasing warm advection through the overnight hours. That said,
the warm advection does look somewhat meager, and should only boost
lows into the middle/upper 40s (to near 50 in northwest Nebraska)
across the area tonight.

The aforementioned shortwave will then begin to eject eastward
across the northern Plains tomorrow afternoon, reaching eastern
SD by tomorrow night. The associated broad surface low will
eject eastward across the Dakotas tomorrow afternoon as well,
dragging a trough axis to near the HWY 83 corridor by late
afternoon. At the same time, a cold front will begin to enter
northwest Nebraska, approaching the meandering trough axis by
late evening. Ahead of the surface trough, dewpoints will climb
into the lower 50s, and will promote at least some MLCAPE,
though lapse rates look to remain somewhat meager (H7-H5 lapse
rates of 6.5-7.5 degC/km) aloft. That said, hodographs do
lengthen with height into the afternoon hours as mid-level flow
increases in response to the approaching shortwave. Deep layer
shear of 30-40kts is anticipated tomorrow afternoon, with
largely straight line hodographs on forecast soundings.
Scattered thunderstorm development is possible ahead of the
encroaching surface trough by late tomorrow afternoon, primarily
near/east of HWY 83. Another regime of convective initiation is
possible across the higher terrain of WY, which could push east
with time into northwest Nebraska. With both regimes, cannot
rule out a strong to briefly severe storm, as the increasing
deep layer shear could support some updraft organization. Hail
would be possible amid the aforementioned straight-line
hodographs, though the meager lapse rates aloft/meager
instability put this somewhat in question. Any organized
convection would support a strong wind threat however, with high
LCLs and very steep lapse rates in the lowest few kilometers.
This activity should push east of the area after sunset, while
also weakening with the loss of diurnal heating.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 335 PM CDT Mon May 13 2024

Another shortwave, on the southwestern periphery of tomorrow`s
system, will push southeast across CO Wednesday, with a renewed
threat for shower and thunderstorm development during the afternoon
hours. As with tomorrow`s thunderstorm activity, meager instability
will primarily hold back any strong storm threat, though this
remains a little uncertain for now. Heights rise in the wake of the
Wednesday shortwave across the central Plains, and shortwave ridging
translates across the area through Friday. This will lead to drier
conditions and quickly warming temperatures, as low level flow turns
southwesterly and increases warm advection. In fact, highs look
to climb into the middle to upper 80s (even approaching 90
across southwest Nebraska) Friday afternoon.

Guidance continues to hint at a return to a more active weather
regime as we head into the weekend and early next week, as
southwesterly flow attempts to establish aloft. This will need to be
monitored closely, as this could lead to increasing precipitation
chances and a returning threat for rounds of severe weather into
next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1218 PM CDT Mon May 13 2024

Areas of smoke/haze from fires across nrn British Columbia and
Alberta drifted into wrn/ncntl Nebraska Sunday night and this
MVFR vsby flight concern will likely linger overnight through
Tuesday morning. MVFR vsbys are most likely tonight and Tuesday
morning as winds become light and the smoke settles toward the
ground.

There are no other flight concerns.

&&

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

&&

$$

SHORT TERM...Brown
LONG TERM...Brown
AVIATION...CDC