832
FXUS63 KLBF 310902
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
402 AM CDT Fri May 31 2024

.KEY MESSAGES...

-  Strong to severe thunderstorms are possible nearly each day
   into this weekend, with some threat lingering into early next
   week.

-  Drier and warmer conditions prevail toward the middle of the
   week, with a brief lull in strong storms.

-  Confidence wanes into late week and next weekend, though a
   return of strong to severe thunderstorm potential exists.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 401 AM CDT Fri May 31 2024

Currently, showers and thunderstorms persist for areas south of I-
80, with the greatest coverage near and south of HWY 23. Additional
thunderstorm development has been observed across portions of
southeast WY and the western Panhandle over the last hour, likely in
response to an increased easterly LLJ. Yet another line of
thunderstorms is pushing through far northeast Colorado. A
stationary front bisects central Nebraska this morning, with a cold
front draped across the northwest Sandhills.

For the rest of this morning, expect continued thunderstorm
development across portions of southwest Nebraska and the Panhandle,
with this activity pushing gradually eastward into early this
afternoon. Deep layer shear, albeit somewhat meager, remains
supportive of updraft organization early this morning, amid 500-1000
J/kg of MUCAPE. The primary zones of convective initiation will
largely be across far eastern WY/western Panhandle, where the
aforementioned easterly LLJ remains positioned. Another will be
across southwest Nebraska, where both the aforementioned
stationary front exists, along with a more muddled surface
pattern, with additional outflow boundaries from earlier
convection. This is just a roundabout way of saying that
thunderstorms cannot be ruled out into early this afternoon for
much of the Sandhills and southwest Nebraska. With such a messy
surface pattern, high-res guidance remains in little agreement
(both with previous runs of the same guidance as well as from
each guidance member) with the placement of convection over the
next several hours. That said, any thunderstorms this morning
will primarily present a threat for locally heavy rainfall, with
slow storm motions and PWAT values above the 90th percentile
across southwest Nebraska. Cannot rule out some hail with the
more robust updrafts as well, though shear remains marginal as
well as meager lapse rates in the mid-levels. By mid-afternoon,
the bulk of storms should be focused near and east of the HWY
183 corridor. Widely scattered storms may linger into the late
afternoon hours across central and north central Nebraska before
finally waning after sunset.

Additionally, by late afternoon another round of widely scattered
convection is expected to develop across the high terrain of CO and
far southeast WY. Initial, more robust, convection is expected along
the Front Range, though this will tend to weaken with time as it
pushes into northeast CO and adjacent far southwest NE. This is
primarily tied to time of day, with storms encountering increasing
CIN, with any storms that reach far southwest Nebraska expected to
do so after sunset. Confidence in any storms reaching far southwest
Nebraska remains low today, though a large hail and strong wind
threat would accompany any storms that do.

A warm front then lifts through the area Saturday morning, with a
return of southerly flow across the entire area. A limited signal
exists in high-res guidance for convection along this warm front
early Saturday morning, though confidence remains too low for
inclusion of POPs at this time. The southerly return flow will push
dewpoints back into the upper 50s to low 60s by late afternoon,
promoting MLCAPE values to ~2000-2500 J/kg across southwest Nebraska
amid steepening lapse rates aloft. As a shortwave trough approaches
the area by early evening, flow aloft strengthens, with increasing
hodograph length with height. Yet again, convection will initiate
across the high terrain of CO/WY, pushing eastward into western and
southwest Nebraska with time into the late evening. Guidance
suggests a propensity for convection to quickly grow upscale as it
moves eastward, pointing to a primarily damaging wind threat. That
said, hodographs do support at least a marginal supercellular
storm mode, and should more discrete convection reach southwest
Nebraska hail and even a brief tornado could not be ruled out.
Any tornado threat looks to be tied to an increasing LLJ
near/just after sunset, with forecast soundings indicating
increasing clockwise curvature in the lowest few kilometers of
the hodograph across southwest Nebraska. Convection looks to
quickly exit the area prior to midnight, with lows then falling
into the mid/upper 50s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 401 AM CDT Fri May 31 2024

The severe threat lingers into Sunday, as another quick moving
shortwave trough pushes across the Plains Sunday evening. At the
surface, a low will push northeast across the Dakotas, dragging a
cold front through the area during the late afternoon/early evening.
Ahead of this boundary, dewpoints will climb into the low/middle
60s, with MLCAPE values potentially soaring to above 2500 J/kg. Deep
layer shear looks more than adequate for strong to severe storms,
and a threat for damaging winds and hail looks to develop as storms
form along the encroaching cold front. Any tornado threat would be
again tied to any discrete convection near/just after sunset, though
this remains very low confidence for now.

Some severe threat may linger Monday and Tuesday, though guidance
varies widely in the placement of surface features and associated
deep layer instability. This will need to be monitored as surface
boundary placement becomes more clear. A brief lull in thunderstorm
activity is expected into midweek, as heights rise aloft and upper
ridging begins to amplify across the western CONUS. Model
discrepancies increase as we head into late week, though the
background northwesterly flow aloft would suggest a return of strong
to severe thunderstorms across western Nebraska late this week and
into the weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1222 AM CDT Fri May 31 2024

The latest CAMS develop some thunderstorms from the panhandle
east into the Sandhills and southwestern Nebraska overnight. Not
sure how this will materialize given the ongoing convection
across southern Nebraska. For now, decided to handle the
thunderstorm threat with a vcts group for the KLBF terminal from
09z to 15z. For the remainder of today, scattered to broken
ceilings ranging from 2000 to 4500 FT AGL are expected at KLBF.
For the KVTN terminal: Expect scattered to broken clouds today
with ceilings generally ranging from 6000 to 8000 Ft AGL.

&&

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

&&

$$

SHORT TERM...Brown
LONG TERM...Brown
AVIATION...Buttler