000
FXUS63 KLBF 281128
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
628 AM CDT Thu Sep 28 2023

...Aviation discussion...

.SYNOPSIS...
Issued at 300 AM CDT Thu Sep 28 2023

Key Messages:

- Elevated fire weather conditions Thursday and Saturday (SW
Nebraska), then Sunday all areas.

- Isolated showers/thunderstorms possible Thursday night/Friday
night mainly over northern Nebraska.

- Very windy conditions possible on Sunday.

H5 analysis tonight had an area of low pressure centered over
northern Indiana. A trough extended south of this feature into the
mid Ohio Valley. North of the low was an area of high pressure over
west central Quebec. Further west, a low amplitude ridging extended
from the northeastern Colorado into southeastern North Dakota.
Further west, a broad trough of low pressure was present over
southwestern Canada into the Pacific NW states. A strong lead
shortwave was located over the Idaho Panhandle. At the surface, low
pressure was located along the Montana/Wyoming border, just west of
Sheridan Wyoming. A frontal boundary extended south southeast of
this feature along the front range of Wyoming to the Palmer Divide
of Colorado. The front then turned east-southeast over the southern
third of Kansas. Overnight, winds were from the east-southeast or
southeast across the area at 10 MPH or less. Skies were clear and
temperatures as of 2 AM CDT, ranged from 54 degrees at North Platte
to 63 degrees at Gordon.

&&

.SHORT TERM...(Today through Friday)
Issued at 300 AM CDT Thu Sep 28 2023

Surface low pressure, currently over northern Wyoming, will slide
east this morning before weakening over central South Dakota. A
cold front trailing this feature will sag south into the
panhandle, stalling over the western Sandhills and northwestern
Nebraska this afternoon. With the front bisecting northwestern
portions of the forecast area today, a wide range in highs will be
expected. Readings will reach into the mid to upper 70s in the
Pine Ridge, with readings around 90 south of Interstate 80. If you
were wondering, record highs for today for Imperial and North
Platte are 99 and 92 respectively. With highs reaching around 90
in SW Nebraska and expected dew points in the upper 40s to around
50, minimum relative humidity may approach 20 to 25 percent in
fire zone 210 this afternoon. Winds should be fairly light with
the frontal boundary just off to the north of SW Nebraska today,
which should preclude any near critical fire weather concerns.
However, with min RH percentages in the lower 20s, fire weather
conditions will be elevated for a short duration this afternoon.
For most of tonight, the frontal boundary will remain anchored
over the western third of the forecast area. A strong low level
jet will temporarily halt the eastward movement of the front this
evening. Toward Friday morning, the low level jet will migrate
into central then eastern Nebraska, pulling the frontal boundary
with it. The inherited forecast had a mention of pops this evening
in the north. Looking at this evening`s CAM`s along with the
NAM12, WARW and GFS, went ahead and took out a mention of pops
this evening. The nose of the low level jet is focused over
northwestern portions of the forecast area, however, upper level
support for convection is well northwest of the area into South
Dakota. As the jet and front migrate east overnight, I did keep a
mention of isolated pops across the northern tier of counties, but
pops were lowered from the inherited forecast. By Friday morning,
there is some signal of convection in northeastern
Nebraska/southeastern South Dakota INVOF the front and the nose of
the low level jet. Moisture will also be more favorable for
showers/storms in the northeastern forecast area as well and low
pops Friday morning were continued in the northeastern forecast
area. As for the threat for strong storms early Friday, deep layer
shear of 30 KTS and very steep lapse rates in the H850-H700 layer
could lead to a hail threat. For Friday, the frontal boundary
will stall from northeastern Nebraska into southwestern Nebraska.
Temperatures will range from the mid 70s in the northwestern
forecast area, to the lower 80s south of a line from Butte, to
Thedford, to Oshkosh.

.LONG TERM...(Friday night through Wednesday)
Issued at 300 AM CDT Thu Sep 28 2023

A trough of low pressure aloft, will quickly deepen across the
western quarter of the CONUS Saturday. Downstream of this feature,
surface winds will shift to the south as low pressure deepens
along the front range of Colorado and Wyoming. Winds will be
fairly strong in the eastern half of Nebraska Saturday. Winds will
be somewhat lighter from southwestern into north central Nebraska
INVOF a inverted surface trough. This feature is more prevalent
in the NAM12 soln compared to the GFS soln. If the GFS soln
verifies, stronger winds will impact western areas. There will be
some fire weather concerns on Saturday, particularly in SW
Nebraska as min RH falls off to 20 to 25 percent. By Sunday,
surface low pressure will deepen further across southeastern
Wyoming. A tight pressure gradient will exist across the state on
Sunday. H85 winds will reach 35 to 40 KTS Sunday afternoon with
unidirectional winds noted to the surface. GFS bufkit soundings
also indicate some gust potential approaching 40 to 45 MPH across
the area Sunday afternoon. That being said, feel fire weather
concerns will be greater on Sunday afternoon, even in light of
higher expected min RH of 30 to 40 percent. Monday will also be a
windy day in advance of an approaching Pacific cold front. As this
feature tracks across the forecast area Monday night, we could
see our best chances for precipitation over the next 7 days. By
Tuesday, the front will be in eastern Nebraska where the focus for
precipitation will reside. Temperatures behind the front will
return to more seasonal levels with highs in the mid 70s Tuesday
and Wednesday. An even stronger, Canadian cold front may impact
the area late next week with the coldest air this fall season. By
next Friday evening, the latest GFS has H85 temps ranging from 2C
in the northeast to around 9C in the southwest. This would equate
to highs around 50 in the northeast, to around 60 in the
southwest.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 628 AM CDT Thu Sep 28 2023

Expect VFR conditions today through tonight with mainly mid/high
clouds overhead.

Winds are expected to be fairly light at the surface, but with a
strong low level jet over western Nebraska there will be low level
wind shear for a couple of hours after issuance with winds at or
above 40kt just off the surface. The low level jet will diminish
Thursday morning with an opportunity for some low end gusts at or
below 20kt through the afternoon. Another round of low level wind
shear will occur Thursday night toward the end of the valid
period as another low level jet ramps up. However with the axis of
the jet further to the east, believe KLBF will have a better
chance for low level wind shear than KVTN.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Buttler
AVIATION...MBS