487
FXUS63 KLBF 101738
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
1238 PM CDT Wed Jul 10 2024

.KEY MESSAGES...

-  Temperatures continue to warm into late week and this weekend,with
   dangerous heat anticipated Friday through Monday across much
   of western and north central Nebraska.

-  Isolated to widely scattered thunderstorms return to the
   area to round out the workweek, and again early next week. A
   few storms could be strong to severe Thursday, with hail and
   damaging winds as the primary hazards.

-  Fire weather concerns may increase into this weekend as
   well, with very warm, dry, and breezy conditions at times.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 358 AM CDT Wed Jul 10 2024

Currently, an upper ridge axis remains anchored across the
Intermountain West, with northerly flow aloft noted across the
Plains. This northerly flow aloft will continue to pull smoke
southward into the area from Canadian wildfires, with hazy skies
returning across northern Nebraska this afternoon. Any surface
impacts look to remain limited, with guidance suggesting the bulk of
the smoke remaining suspended aloft.

By late this afternoon, a weak surface trough will extend
northeastward, bisecting portions of central Nebraska, from broad
surface low pressure located across eastern CO/western KS. Some high-
res guidance suggests widely isolated convection initiating in the
vicinity of this boundary during the late afternoon hours. Deep
layer shear remains somewhat marginal across central Nebraska today,
though any thunderstorms that do form could produce gusty winds in
the well mixed environment. The signal from guidance supports
at least a slight chance to low-end chance (15-30%) mention for
thunderstorms generally near and east of HWY 183. Temperatures
remain near to just slightly warmer than yesterday across the
area, with highs in the upper 80s to low 90s.

By tomorrow, the upper low will continue to encroach on the area,
with warm air continuing to stream in aloft. This boosts highs yet
again across the area, with highs climbing into the upper 90s near
and west of HWY 61. By late tomorrow afternoon, a subtle shortwave
will round the eastern side of the upper ridge axis, with an
associated surface trough sliding eastward into the Panhandle.
Isolated to widely scattered thunderstorm development will be
possible tomorrow afternoon in the vicinity of this surface trough.
Hodographs do elongate somewhat with height with the approach of the
mid-level wave, and deep layer shear does look a little more
supportive of organizing any convection that does form. Again,
strong outflow winds look to be the biggest threat near and west of
HWY 61, with deep inverted-v thermodynamic profiles amid robust T-Td
spreads (35-40F). The threat for large hail is somewhat less
certain, with warm temperatures aloft (H7 Ts of ~14-15C).

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 358 AM CDT Wed Jul 10 2024

The primary concern as we head into the long term will be the long
advertised dangerous heat, as the upper trough axis approaches
and passes overhead. As the ridge axis approaches H5 heights
will rise and exceed the 90th percentile climo, with low level
warm advection pushing temperatures at H7 above the 90th
percentile (and even near the 99th percentile on Sunday) as
well. This should continue to push temperatures upward across
the area each day, with widespread 100s by Sunday afternoon.
Increasing heat concerns are expected as early as Friday south
of I-80, becoming more widespread through the weekend. Areas
near and south of HWY 23 are especially concerning, with a
threat for highs exceeding 100F each day Friday through Monday.
This would suggest the potential need for an Excessive Heat
Warning, with prolonged heat over multiple days. Confidence in
the longevity of the heat wanes with northward extent, tied in
part to a frontal boundary expected to push into the area
Monday. That said, widespread heat index values of 100F+ are
looking increasingly likely on Sunday across all of western and
north central Nebraska, as this looks to be the warmest day by
far. And even though explicit heat advisory criteria may not be
met each day Friday, Saturday, and Monday for areas near and
north of I-80, heat index values will still climb into the
middle and upper 90s. This level of heat can still be hazardous,
especially for sensitive groups. The bottom line is, a period
of dangerous heat is looking increasingly likely Friday through
Monday for all of western and north central Nebraska, and those
with outdoor plans should monitor later forecasts and plan
accordingly.

The increasing heat and dry conditions could also lead to increased
fire weather concerns this weekend, especially across western
Nebraska where the driest conditions are anticipated. Fuel status
remains uncertain, but will have to monitor how things progress as
the dry and hot conditions continue through the week. Additionally,
breezy winds are expected at times, though confidence in stronger
gusts remains low for now. This could especially be true across
portions of southwest Nebraska, as ridge breakdown occurs and winds
strengthen near and behind the approaching surface cool front.

As for Monday, the upper ridge begins to flatten out aloft, with an
upper low ejecting eastward across the Canadian Prairies. An
associated surface low will eject eastward into Ontario by late
Monday afternoon, with a cool front stretching southwest from this
low across the upper Midwest and into the Dakotas. The placement and
speed of this boundary remains low confidence as of now, though will
drive how widespread any dangerous heat concerns will be Monday.
Current thinking is areas near and south of I-80 will have to wait
another day to get a reprieve from the heat, with areas further
north finally returning to the low 90s. The approach of this
boundary will also bring a return of scattered thunderstorm chances,
which look to linger into midweek as additional shortwave troughs
cross the Plains in the wake of ridge breakdown. Any threat for
severe weather remains uncertain for now, though some threat may
return as a belt of stronger westerlies aloft may encroach on the
area as we head into early/middle of next week. &&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1225 AM CDT Wed Jul 10 2024

VFR will continue for western and north central Nebraska
terminals through the forecast period. Light and variable winds
will strengthen somewhat from the northeast midday and become
more easterly toward sunset.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1238 PM CDT Wed Jul 10 2024

VFR will continue for western and north central Nebraska
terminals through the forecast period. Winds will remain below
10KT through the TAF period. Light north winds this afternoon
will become light southeast this evening, then light southerly
Thursday morning.

&&

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

&&

$$

SHORT TERM...Brown
LONG TERM...Brown
AVIATION...Roberg