071
FXUS63 KLBF 300009
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
709 PM CDT Mon Apr 29 2024

.KEY MESSAGES...

-  Thunderstorms return to the area tonight into tomorrow, and
   persist nearly each day into early this weekend.

-  Elevated to near-critical fire weather conditions are
   expected to develop across western Nebraska Tuesday afternoon
   with the combination of gusty northwest winds and low
   humidity.

-  Strong to severe thunderstorms will be possible both
   tomorrow afternoon and again on Wednesday, primarily across
   central (Wednesday) and north central (Tuesday/Wednesday)
   Nebraska.

-  Temperatures fluctuate around average (60s) through the
   workweek with the passage of a few frontal boundaries, before
   climbing above average into early next week (mid/upper 70s).

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 400 PM CDT Mon Apr 29 2024

Currently, scattered showers have developed north of I-80, in a
narrow corridor of elevated instability. Temperatures range from the
low 60s in north central Nebraska to the lower 70s in southwest
Nebraska. Aloft, an upper low was centered over ND/MN, with broad
zonal flow on its southern periphery across the central Plains.

For tonight into tomorrow, active weather returns to the area, as a
quick moving upper low drops southeastward through the Intermountain
West, reaching the northern Plains early tomorrow morning. At the
surface, lee cyclogenesis begins across northeastern WY/eastern MT,
dragging a warm front northward across the area into the Dakotas.
The deep southerly flow will both boost lows tonight back into the
40s, and lead to increasing moisture return flow into the area. This
also looks to generate at least scattered showers in the broad warm
advection regime overnight, though any severe threat with this
activity looks low. Surface dewpoints will climb into the low 50s
for areas east of HWY 183 by early tomorrow afternoon, leading to
increasing instability.  For areas further west, the surface cold
front should begin to push through the area from west to east,
reaching the HWY 183 corridor by early afternoon. It is ahead of
this boundary where convective development is anticipated, and a
window will exist tomorrow afternoon for strong to severe storms,
primarily east of HWY 11. Some uncertainty remains with respect to
this however, largely tied to the speed of the aforementioned
cold front and how much time is maximized in the warm sector
during better diurnal heating. Deep layer shear profiles do
support organized convection, with good speed shear aloft
indicated in area forecast soundings. Large hail and damaging
winds look to be the greatest threats, with initial
discrete/semi-discrete updrafts presenting the best chance for
hail before quick upscale growth leading to increased damaging
wind potential. The threat locally will likely be brief, on the
order of a few hours, and tied to the progression of the surface
cold front. This will need to be monitored closely as mesoscale
details become more clear. High temperatures will range from
the 60s across northwest Nebraska where the surface front should
pass in the morning, to the low/mid-70s in southwest and
central into north central Nebraska.

Elevated to near-critical fire weather conditions look to develop
across western Nebraska in the wake of the surface cold front
tomorrow afternoon as well, as dry air is ushered into the area.
This will send relative humidity values falling into the upper teens
to low 20s for areas near and west of HWY 61. More concerning, as we
mix out during the afternoon, winds will quickly strengthen from the
northwest, tapping into a belt of 30-40kts of H7-H85 flow aloft.
This should promote wind gusts approaching 40 miles per hour
across western Nebraska with ample downward momentum transfer in
the well mixed boundary layer. The overlap of strong northwest
winds and low humidity could lead to a period of near Red Flag
conditions, considering current fuel conditions from recent
greenup.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 400 PM CDT Mon Apr 29 2024

The threat for strong to severe storms persists into Wednesday, as
yet another shortwave is progged to cross into the Plains by late
Wednesday evening. At the surface, the aforementioned cold
front will quickly stall across central Kansas, with lee
cyclogenesis beginning across southeastern CO. This places our
area in postfrontal broad east-southeasterly upslope flow. The
easterly flow will pull the moisture that was ushered out behind
tomorrow`s cold front right back into the area, with dewpoints
increasing through the afternoon. The exact degree of moisture
recovery remains somewhat uncertain, and this will determine the
areal coverage of any severe weather threat. Portions of
central and north central Nebraska look to have the best shot at
higher dewpoints/greater instability, in closer proximity to
the surface warm front in central Kansas. Hodographs look more
than adequate to support severe weather across much of the area
as well, with ample curvature in the lowest few kilometers and
increasing speed shear aloft. Synoptically, this does resemble a
regime that is favorable for severe weather across western
Nebraska as well, with convection initiating across the Front
Range of Colorado in the broad upslope and pushing northeastward
into the area. Should discrete storms sustain themselves into
western and southwest Nebraska, a threat for large hail and
damaging winds would be possible, again driven by the degree of
instability with northeastward extent.

The pattern remains active into the latter part of the workweek and
into early this weekend, as multiple shortwaves look to push through
the area in the quasi-zonal flow aloft. Nearly daily shower and
thunderstorm chances exist through Saturday across much of the area.
The degree of any severe weather threat will be driven by surface
features each day, though mid/upper level flow does look strong
enough to warrant at least some concern for severe weather.
Mesoscale features will need to be watched closely, and additional
threats for severe weather may exist as we wrap up the workweek.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 701 PM CDT Mon Apr 29 2024

VFR conditions are expected to prevail across all of western and
north central Nebraska tonight into Tuesday. Low-level wind
shear will be a concern across parts of central and north
central Nebraska late tonight. A cold front will witch winds to
the northwest Tuesday. Gusts over 30kt will be possible Tuesday
afternoon.

&&

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

&&

$$

SHORT TERM...Brown
LONG TERM...Brown
AVIATION...Taylor