-- Discussion containing changed information from previous version are highlighted. --
650
FXUS63 KLBF 190552
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
1252 AM CDT Wed Jun 19 2024

.KEY MESSAGES...

- Cool conditions on Wednesday with high temperatures 10 to 20
degrees below seasonal values. However, temperatures quickly rebound
back into the 80s for the remainder of the week into the weekend.

- Near daily shower and thunderstorm chances continue across the
area each day through the rest of the week into the weekend. The
severe threat remains uncertain at this time.

&&

.SYNOPSIS...
Issued at 206 PM CDT Tue Jun 18 2024

Recent GOES-16 WV and RAP 500-mb analysis showed a dome of high
pressure centered over the east coast with a ridge extending north-
northeastward into northern Quebec. Southwest flow aloft continues
across the region as an upper-level trough swings across the
northern Plains. At the surface, low pressure was moving
northeastward out of eastern South Dakota into Minnesota. An
attendant cold front extended southwest into eastern Nebraska and
central Kansas to another area of low pressure centered over
southwestern Kansas. This front advanced through western and
north central Nebraska this morning allowing the strong
overnight winds to subside some and shift towards the
northwest. At 2 PM CT, temperatures ranged from 61 degrees at
O`Neill to 76 degrees at Imperial.

The aforementioned cold front has sagged a bit further to the
southeast than previously thought with convection initiating
along the boundary in our eastern neighbor`s CWA. This ongoing
development is occurring south and east of the local area and
should continue to move north and east as the afternoon and
evening progresses. The potential for a brief shower or
thunderstorm exists across far north central Nebraska, generally
areas east of Highway 183. Do believe the bulk of the severe
threat will reside outside of these areas, though cannot rule
out some hail or gusty winds should a stronger storm develop and
maintain itself. Anything that does develop should exit the
previously mentioned areas by 00Z this evening.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 206 PM CDT Tue Jun 18 2024

Tonight... Thanks to the cold frontal passage, overnight lows will
cool back into the 40s and 50s across western and north central
Nebraska. Clouds will continue to back build over the region late
tonight with relatively light winds out of the north and east as
surface high pressure nudges south out of Montana. A shortwave
embedded in the flow aloft combined with outflow from the
storms to the south should be enough to trigger scattered showers
and non-severe thunderstorms to develop after 06Z across
southwest into portions of central Nebraska.

Wednesday and Wednesday Night... The activity from overnight
is expected to wane across the area through Wednesday morning
with a cloudy and cool day is in store for the area. High
temperatures will be in the mid 60s which is 10 to 20 degrees
below normal for mid-June. An upper-level shortwave ejecting out
of the central Rockies Wednesday evening will provide another
focus for showers and thunderstorms to develop, continuing
overnight. Given the cloud cover and cool temperatures,
instability will be meager (MLCAPE 300 to 500 J/Kg) with weak
deep-layer shear (20 to 30kt), thus anticipate non-severe
thunderstorms with this activity. These showers and
thunderstorms should bring some moisture to portions of
southwest and north central Nebraska, though generally 0.25 to
0.75" appears most likely. Locally higher amounts up to 1"+ may
be observed for areas generally east of Highway 83.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 206 PM CDT Tue Jun 18 2024

Thursday... Showers and thunderstorms are expected to linger into
Thursday morning, waning through the afternoon hours. Another upper-
level shortwave ejecting eastward out of Wyoming and Colorado will
provide a focus for isolated to scattered thunderstorms across the
Nebraska Panhandle Thursday afternoon and evening. Mid-level warm
air advection (WAA) will result in a capping inversion and when
combined with persistent cloud cover, convection may be limited
Thursday. With the position of a lee trough near the
Colorado/Wyoming border, southeasterly surface flow will increase,
helping amplify southeasterly low-level flow and moisture advection
across the area. In fact, both the NAEFS and ENS guidance
highlighting precipitable water (PWAT) values approaching the
99th climatological percentile, especially north of a warm front
expected to lift northward across the Panhandle into the
Sandhills. Despite this, details remain rather murky resulting
in uncertainty on the degree of the severe risk Thursday given
large spread amongst model guidance. Will continue to monitor
the severe potential during this period as CAMs get into this
time range.

Friday and beyond...The cool conditions felt on Wednesday will be
short-lived as temperatures warm back into the 80s as the upper-
level ridge retrogrades westward into the weekend. Continued
southwesterly flow aloft with additional northern stream
disturbances tracking across the region will keep the extended
forecast in a relatively active pattern. While recurring afternoon
and evening thunderstorm chances exists in the extended, the degree
of severe potential and coverage remains in question. A return to
above normal temperatures and drier conditions will be felt heading
into early next week as the upper-level ridge re-amplifies
across the Desert Southwest, extending north into the northern
Plains.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
-- Changed Discussion --
Issued at 1250 AM CDT Wed Jun 19 2024

Expect VFR conditions through the first half of the valid period
though expect an accelerating downward trend this afternoon
through the end of the valid period. There may be some light
showers around but will not include in the TAFs and will
introduce precipitation late this afternoon when probabilities
become higher and expect showers/thunderstorms will increase in
coverage and spread up from the south after 00Z. KLBF looks to
sink to IFR toward the end of the valid period but expect MVFR
to hold through the latter portion of the valid period at KVTN.

There may be a few northerly gusts early especially at KVTN but
overall expect winds will veer from northeast to easterly and
generally remain 10kt or less, though expect there will be a few
gusts at onset of precipitation.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...Viken
SHORT TERM...Viken
LONG TERM...Viken
AVIATION...MBS