939
FXUS63 KLBF 111947
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
247 PM CDT Sat May 11 2024

.KEY MESSAGES...

- Daily high temperatures remain near seasonal to above
  seasonal through the work week. Overnight lows mostly in the
  40s, limiting any frost concerns this week.

- Widespread chances of showers and thunderstorms tomorrow
  afternoon, with little to no severe weather expected.

- The best chance for showers and thunderstorms comes Tuesday
  night into Wednesday morning, with some question on the
  potential for severe storms. Slight chances (less than 30
  percent) of showers persist most days of the week.

&&

.SYNOPSIS...
Issued at 245 PM CDT Sat May 11 2024

Upper air analysis and satellite imagery place an upper level cut
off low over northern Arizona. Further west, another wave is noted
across the northern Pacific Ocean, with a ridge off the West Coast
and a trough behind it. At the surface, high pressure is the
dominant feature over the Plains. The major weather story has been
the recent space weather activity, with the aurora visible last
night and an ongoing G4 geomagnetic storm this morning and early
afternoon.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 245 PM CDT Sat May 11 2024

Tonight, as the upper level low slowly tracks east, areas of showers
and potentially thunderstorms are possible across portions of
southwest Nebraska. The most likely area for rain tonight is along
and south of a line from roughly Oshkosk to Broken Bow. Given the
very limited forcing, no severe weather is expected with
thunderstorms this evening.

The other big weather story this evening remains the active space
weather that caused aurora sightings across Nebraska and a fain
amount of the United States last night. The ongoing solar activity
has been quite intense, with possible impacts on radio and GPS. The
Space Weather Prediction Center has extended their warning for
Geomagnetic K-Index of 7 or greater, which may create an additional
chance to see the aurora across western and north central Nebraska
tonight. However, the biggest challenge will be sky cover this
evening. Clouds are expected to move in this evening, with possible
precipitation, again along a line from Oshkosh to Broken Bow. Areas
to the north may be a bit more lucky with sky conditions, but will
merit keeping an eye on for those hoping to get another chance at
the aurora. The latest space weather information and aurora forecast
can be found at swpc.noaa.gov.

Chances of showers and thunderstorms continue on Sunday through
Monday morning, as the upper level low is closer in proximity to the
south and a cold front sweeps down from the north. Though
thunderstorms are expected, the severe potential is low at this
time, with marginal amounts of CAPE and fairly weak shear values.
Current CAM guidance keeps storms tomorrow afternoon rather spotty
in nature, keeping expected rain totals fairly limited, generally
under one quarter of an inch. However, showers and storms may
produce some locally heavier amounts, with expected PWAT values
ranging from one half inch to one inch.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 245 PM CDT Sat May 11 2024

The upper air pattern remains fairly progressive over the course of
the week. By Monday afternoon, the upper level low is expected to be
over eastern Kansas, with nearly zonal flow aloft over wester and
north central Nebraska. The nearby upper level low may still provide
enough forcing for some light showers, mainly across southwest
Nebraska and the Sandhills, however, guidance remains fairly
spotty on this. Ensembles are a bit more optimistic for
precipitation greater than or equal to one one-hundredth of an
inch (around 90 percent chances across), but limited to the
southern portion of the state for one tenth of an inch or
greater.

By Tuesday, the upper level pattern supports the best chance of
showers and thunderstorms next week. An upper level shortwave begins
to deepen across Wyoming. A surface system tracking through the
region late Tuesday afternoon into the early morning hours of
Wednesday will be the focus for showers and thunderstorms. For now,
the severe weather threat is still a bit in question, but given the
support and forecast soundings, will definitely be worth keeping an
eye on. Though there is still some variance in the individual
models, there has been some consensus in a narrow tongue of CAPE
nearly along Highway 83, with just enough shear support to support
severe convection. However, there still is some question model to
model in how much CAPE and shear will be available.

After the shortwave trough lifts to the north, the upper level
pattern remains mostly to the north and south of the region. There
is still a little uncertainty in the actual track of the upper level
flow, and ensembles pick up on that uncertainty. Ensembles highlight
that chances of measurable precipitation for the rest of the week
remain generally in the 20 to 30 percent range. With the upper level
pattern remaining fairly progressive, daily highs should remain
nearly seasonal to above seasonal throughout the week. For
reference, seasonal daily highs are in the low 70s across the
region. As for overnight temperatures, generally expected
temperatures will be in the 40s throughout the week, which will
limit the chances for frost across the region.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1215 PM CDT Sat May 11 2024

Sfc low pressure across Manitoba will move east and be located
across nrn Ontario by 12z Sunday. Meanwhile, an upper level
disturbance across the srn Rockies this afternoon will move very
slowly east and be located across the Colo Plains by 12z Sunday
morning also. This system has the potential to produce isolated
showers and thunderstorms along and south of I-80 tonight which
become scattered in the same area by 18z Sunday.

&&

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

&&

$$

SYNOPSIS...Richie
SHORT TERM...Richie
LONG TERM...Richie
AVIATION...CDC