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410
FXUS63 KLBF 192034
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
334 PM CDT Wed Jun 19 2024

.KEY MESSAGES...

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- Abundant moisture will invade wrn/ncntl Nebraska tonight and
  remain across the region through Friday night. Weather
  conditions will support heavy thunderstorms which could become
  severe in some areas Thursday and Friday but the severe
  weather threat is still under review by the SPC.
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&&

.SHORT TERM /THROUGH THURSDAY/...
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Issued at 330 PM CDT Wed Jun 19 2024

A few things supporting locally heavy rainfall tonight are 850-700mb
moisture and theta e transport into the Sandhills is strong. In
fact, PWAT will double in about 18 hours, between 12z this morning
and 06z tonight reaching values of 1.50 inches. BUFkit also suggests
warm precip processes will be significant operating to around
11Kft. The focus is a warm front predicted to lift into wrn Nebraska
and be located near or south of the SD border by Thursday morning.
It is worth noting, winds aloft will be fairly strong and wrn
Nebraska will be positioned in the RR quad of a southwest to
northeast oriented 300mb Jet. This should present a negative force
on the northward moving warm front. The result is the potential for
back-building storm development which would also produce cool
outflow impeding the northward motion of the warm front.

The modest low level jet tonight, around 30kts, will veer off toward
morning and the RAP model shows a 700mb dry intrusion which will
cutoff the deep convection. Still light to moderate rain could still
occur below the dry air at h700mb.

The POP forecast leans on the HREF which is a blend of models
favoring the Sandhills and ncntl Nebraska for an inch or more
rainfall tonight. The HREF probability for an inch or more rainfall
is 60 percent or higher from Grant to KOGA to KTIF to Rose by 12z
Thursday morning.

The next heavy rain chance should develop Thursday afternoon across
nwrn Nebraska where the front will be hung up. The dynamics look a
bit strong as a closed h850mb low should from circulating from sern
WY northeast to near Gordon by 12z Friday morning. The HREF probs
for 1 inch of rainfall increase to 90 percent from Ellsworth Neb. to
Martin SD. Thus, to focus appears to be strong with an inverted trof
setting up across far wrn Nebraska.

This set-up will be favorable for at least isolated strong or severe
storms late in the afternoon and in the evening. A fairly strong
"hot prod" of warm air advection will be directed due north through
ern Colo and the srn Panhandle, aimed at the stationary front to the
north according to the RAP. A narrow belt of 2500-3000 J/KG MLCAPE
should be located just south of the cold front and deep layer shear
near 50kts would support severe storms.

The CAMs are mixed in the location of the storms, all of which
suggest at least isolated HP storm development, vary considerably
with the direction of storm development. Some track the storms
northeast into SD while others more easterly through the Sandhills.
The HREF is tracking the storms more northeast, consistent with the
upper level flow. It`s worth noting some CAMs show merging storm
activity resulting in 1 hour storm totals of 2 inches or more.

Our forecast Thursday night is similar to the WPC QPF favoring
northwest Nebraska for the best rain chances.
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&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
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Issued at 330 PM CDT Wed Jun 19 2024

An active weather situation should continue through Friday evening
followed by a cold front which will stabilize the atmosphere
for a few days. Warmer drier air will follow with a modest heat
wave setting up through Wednesday.

Focus, instability and 30-50k wind at h500-300mb could support
strong to severe storms late Friday. At 60hrs, the NAMnest is
hinting at this with storms firing along a stalled front draped from
Chappell to Springview. A blend of the models places this front, or
focus, farther northwest across northwest Nebraska. The model
consensus suggests severe storms will most likely form along and
north of highway 20. Warm air advection for storm development will
be moving north through ern Colo/far west KS favoring wrn Nebraska
and PWAT will remain near 1.50 inches.

The upper level ridge across the ern U.S. will retrograde west next
week and h700mb temperatures will warm to around 15C presenting a
relatively stable atmosphere. At the same time, sfc low pressure
will form across the nrn Plains and this should set up a modest heat
wave across wrn/ncntl Nebraska. POPs are low next week, isolated to
low-end chance.
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&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1230 PM CDT Wed Jun 19 2024

VFR conditions are expected to prevail into this afternoon
across western and north central Nebraska. By this evening, low
stratus will overspread the area from south to north, with MVFR
then widespread IFR/localized LIFR CIGs expected overnight.
Showers and thunderstorms then overspread the area tonight into
tomorrow morning as well, with lowered visibilities
anticipated. The lowered categories will persist through the end
of the valid period, though quick improvement to VFR is
expected to begin from south to north into tomorrow afternoon.

Winds remain southeasterly into tonight and tomorrow morning,
at around 10 to 15kts.

&&

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

&&

$$

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