-- Discussion containing changed information from previous version are highlighted. --
293
FXUS63 KLBF 212345
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
Issued by National Weather Service Des Moines IA
645 PM CDT Tue May 21 2024

.KEY MESSAGES...

- Localized frost potential in portions of the Panhandle tonight.

- A brief reprieve from showers and thunderstorms Wednesday
  afternoon through Thursday morning, with slightly cooler than
  average temperatures.

- Chances of showers and thunderstorms, with potential for
  severe thunderstorms, returns again Thursday afternoon into
  the evening. SPC has issues a Marginal Risk for severe weather
  Thursday afternoon.

- The pattern remains active through the weekend, bringing
  slightly cooler than seasonal temperatures and chances of
  precipitation throughout the weekend. At this time, the severe
  weather potential remains uncertain. &&

.SYNOPSIS...
Issued at 329 PM CDT Tue May 21 2024

Upper air analysis and satellite imagery reveal an upper level low
over southern Saskatchewan, with a trough over western Utah. A
shortwave is noted ahead of the main trough over western Kansas. At
the surface, a strong low pressure system is located over eastern
Nebraska, which is the focus for severe thunderstorms across eastern
Nebraska into central Iowa this afternoon. Across western Nebraska,
mostly overcast skies are observed on satellite, on the back side of
the strong low pressure system.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 329 PM CDT Tue May 21 2024

As the upper level trough and associated surface system move further
east this evening, a low amplitude ridge begins to settle over the
region, bringing a small reprieve from showers and thunderstorms.
Cannot rule out the potential for some very light precipitation this
evening, but generally expect any precipitation to be a few
hundredths at most. Lingering cloud cover overnight should help
limit temperatures cooling off too dramatically, but will need to
keep a close eye on portions of the Panhandle for potential patchy
frost. The area of greatest concern for patchy frost will be
northern Garden and southern Sheridan counties. At this time, given
the cloud cover and potential light showers, confidence remains low
for frost, but still worthy of a mention.

For Wednesday, clouds are expected to clear out, bringing mostly
clear skies. The low amplitude ridge is expected to become more
zonal in nature ahead of the approaching trough. Temperatures remain
slightly cooler than average, generally in the upper 60s to lower
70s across the region. Looking into Wednesday night, cannot
completely rule out the potential for some light showers and rumble
of thunder across southwest Nebraska, however, remain fairly
confident in a dry night.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 329 PM CDT Tue May 21 2024

By Thursday, the upper level trough will have progressed eastward,
and sets up another set up for potential severe weather. Model
guidance suggests a strong low level jet and respectable moisture
advection ahead of the advancing system. The surge of moisture
should provide dewpoints in the 50s across the region, and forecast
soundings are supportive of severe weather. Additionally, initially
clear skies will help temperatures climb into the upper 70s to lower
80s. The Storm Prediction Center has already placed a Marginal Risk
of severe weather across most of the region on Thursday, however
this is likely going to be refined as confidence improves in the
synoptic set up. The biggest forecast question is just how far north
the moisture advects. This seems to be the biggest factor in
convective mode, as well as whether or not the cap will break.
Afternoon guidance suggests that if the moisture can reach the
region, convection may be more discrete in nature, and profiles were
suggestive of large hail. However, other guidance that had more
limited moisture tended to keep potential cells more elevated. As
this critical detail is resolved in follow on forecasts, will have a
better idea on timing and mode of potential severe weather Thursday
afternoon.

The upper level pattern remains fairly active through the weekend,
with another trough and upper level low tracking through the region.
This looks to bring yet another round of showers and thunderstorms
across western and north central Nebraska. Currently, appears that
Sunday and Monday will be the better precipitation chances, but
ensemble guidance keeps a 30 to 40 percent chance throughout the
weekend. At this time, the potential for severe weather is
uncertain. Confidence will increase in follow on forecasts as the
track and timing of the upper level low is refined.

Although the severe potential remains uncertain, temperatures look
to be fairly consistent, with slightly cooler than seasonal
temperatures expected this weekend. Looking at some of the
temperature guidance this weekend, this may only be by a few
degrees, as typical highs are around the mid 70s, and forecast
temperature spreads are in the low to mid 70s.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
-- Changed Discussion --
Issued at 645 PM CDT Tue May 21 2024

VFR conditions are expected to prevail through tomorrow evening
across western and north central Nebraska. Stratus with low-
end VFR ceilings will persist for a few more hours before
gradually exiting the area to the east. Winds weaken from the
north through sunset, becoming light westerly by sunrise
tomorrow morning.
-- End Changed Discussion --

&&

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

&&

$$

SHORT TERM...Richie
LONG TERM...Richie
AVIATION...Brown