718
FXUS63 KLBF 090623
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
123 AM CDT Sun Jun 9 2024

.KEY MESSAGES...

- Limited threat for strong to severe thunderstorms across
  southwest Nebraska this evening. Primary threat will be
  damaging wind gusts but isolated severe hail and heavy rain
  are also possible.

- The next system to bring rain and thunderstorms arrives late Monday
  into early Tuesday as a cool front drops through the area. A
  few storms may be strong to briefly severe across the
  Panhandle.

- Strengthening ridge towards the middle and late part of the
  week will support increasing temperatures. Signals continue to
  increase for hot days Wednesday and Thursday as highs climb
  into the middle to upper 90s across the southwest.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 317 PM CDT Sat Jun 8 2024

Scattered rain with a few embedded thunderstorms continue to track
west to east across the Sandhills into central Nebraska. This
activity will continue through late afternoon as a weak shortwave
moves out of eastern Wyoming. Rainfall amounts have been light with
the heavier cores being limited to rural areas of the Sandhills. A
few locations may surpass a tenth of an inch but this should remain
on a fairly isolated bases.

Surface frontal boundary from Friday has shifted south into Kansas
and with approaching high pressure from the north, surface flow has
gradually shifted from northeasterly to easterly. This will set us
up for another round of strong to potentially severe weather as
upslope forcing should allow for scattered to widespread
thunderstorms to develop off the Front Range and gradually shift
east/southeast with time this afternoon and evening. With the
ongoing activity largely north of Interstate 80, cloud cover has
remained heavy and greatly limited diurnal warming. Further south to
the I-80 corridor and points south, more clearing has occurred which
has allowed afternoon temperatures to reach the middle 70s to near
80 degF by 18z (1pm). Mesoanalysis guidance depicts a sharp gradient
in instability with the bulk of the greatest values (> 1500 j/kg
MLCAPE) remaining south of the Nebraska/Kansas state line. Though a
slight northward shift is expected with this later this afternoon as
low level flow continues to veer to the east-southeast, the more
favorable environment should remain south as MLCAPE values will
likely only climb to around 1000-1250 j/kg versus 1500-2500 j/kg
further south. Deep-layer shear is more than adequate for storm
organization as 0-6km BWD will easily surpass 40 knots. Storms
currently developing near the I-25 corridor of northern
Colorado/southeastern Wyoming should quickly grow upscale as cold
pools congeal and activity moves off the higher terrain. Storm track
will generally follow the instability gradient which will likely
steer it into far southwest Nebraska and northwest Kansas. The
environment locally is supportive of at least an isolated severe
threat...MLCAPE ~1000 j/kg, strong deep-layer shear, steep mid-level
lapse rates of 7+ C/km, and PWAT values of 1.00"+ which nears the
99th percentile for early June. Given all this, believe a few
reports of damaging wind and severe hail are probable. Am also
concerned in a threat for briefly heavy rain though quick
progression of storms should limit any flooding threat. Can`t rule
out a few locations seeing up to 1.5" of rain before activity
departs. They say the "trend is your friend" and it`s interesting to
note that the HRRR signal for damaging wind gusts locally has
decreased with concurrent runs of the model. This is noteworthy but
likely not enough to suggest the severe threat is no more. For now,
will continue to monitor upstream evolution of convection and adjust
the forecast as necessary. Timing would favor after 4pm CDT and
likely be closer to a 6-9pm CDT window for our far southwest.
Activity should quickly exit with the bulk of short-term models
depicting dry conditions in the local area by Midnight. Will
maintain a low-end PoP through the overnight hours for our west
and southwest zones, however, as modest low-level lift remains
in an anomalously moist environment though most locations will
likely remain dry. With encroaching high pressure, cooler
temperatures are likely with upper 40s to low 50s outside the
lingering stratus and middle 50s in.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 317 PM CDT Sat Jun 8 2024

Sunday...Mid-level heights begin to rise as ridging noses into the
central and southern Plains. Modest high pressure will drift through
the middle Missouri River valley. With the local area on the western
periphery of this feature, southerly flow will remain prevalent.
This will continue to paint a narrow ribbon of greater moisture
across the High Plains to include lingering low-level cloud cover.
This will likely inhibit afternoon temperatures somewhat with
forecast highs ranging from near 80 degF in the far east to low 70s
in the west.

Monday and Tuesday...broad ridging will center across the Plains by
early Monday morning. Flow will flatten as a northern stream system
translates east across southern Canada. This will drag a cool front
south into the area. Ahead of this, the persistent southerly flow
will maintain anomalous moisture with PWATS exceeding 1"
generally for areas west of Highway 83. These values will
surpass the 90th percentile in NAEFS climatology. With fairly
strong frontal forcing, scattered to widespread thunderstorms
are likely to develop for the late afternoon and evening hours
favoring the Sandhills north into South Dakota. NBM
probabilities of exceeding 0.25" QPF for the period are roughly
50/50 for the far northwestern Sandhills and around 25% for
exceeding 0.50". This is fairly modest considering deterministic
solutions depict more widespread 0.50" or greater rainfall.
Given discrepancies between ensemble solutions, however, will
defer to later forecasts for more precise details. Latest SPC
Day 3 outlook shows a Marginal Risk for the eastern Panhandle.
For now believe this is adequate though both shear and
instability are somewhat limited. Highs both Monday and Tuesday
will climb into the upper 70s to lower 80s.

Wednesday and beyond...signals for a couple days of more summer-like
weather continue to strengthen in the local area. Broad ridging will
again strengthen over the southern half of the CONUS. Meanwhile, a
system will sit off the Baja of California as modest troughing
slides east along the Gulf Coast. High pressure will strengthen
across the southwest behind the departing trough which will again
enhance southerly flow in the region as broad low pressure settles
in the Great Basin. This will promote steady southerly flow
advecting in richer low-level moisture. At the same time, ridging
will continue to build north with h5 heights exceeding the 90th
percentile. This will bring with it anomalous warmth in the mid-
levels as h5 and h7 temperatures surpass the 90th percentile by late
Wednesday, Thursday, and possibly lingering into Friday. All this to
say it`ll be a couple of hot and humid days. NBM ensemble guidance
shows fairly reasonable 25th to 75th percentile spread at only 6 and
9 degF respectively and the 50th percentile values pushing in the
low to middle 90s. Combined with dew points climbing into the upper
50s to lower 60s, will be monitoring for heat indices climbing into
the upper 90s. For now, no headlines are expected though with these
first hot days of the season, messaging will be increased to keep
people adequately aware. Precipitation chances look to linger
through the period as well, particularly Friday into Saturday as NBM
highlights 30-40% probabilities of seeing > 0.25" QPF. This is tied
to an approaching shortwave interacting with the moist and hot
airmass on the northern periphery of the upper ridge. Overall
though, our days of high heat should be brief during the forecast
period as ridging wanes by the following weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1254 AM CDT Sun Jun 9 2024

VFR conditions are expected to prevail across the area through
today (Sunday). The exception will be the possibility of MVFR
and local IFR ceilings developing early this morning across far
southwest Nebraska extending northward into the Panhandle. These
ceilings will lift by this afternoon. Winds will become
southeast at 5-15 kts by this afternoon.

&&

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

&&

$$

SHORT TERM...NMJ
LONG TERM...NMJ
AVIATION...Taylor