ne discuss
Office: LBF
FXUS63 KLBF 041716
AFDLBF
Area Forecast Discussion
National Weather Service North Platte NE
1216 PM CDT Sat May 4 2024
.KEY MESSAGES...
- An all hazards severe weather event is possible Monday
afternoon, generally affecting areas along and east of
highway 83.
&&
.SHORT TERM /THROUGH SUNDAY/...
Issued at 341 AM CDT Sat May 4 2024
Drier air and clearing skies have swept into wrn and ncntl Nebraska
this morning. A check on afternoon cumulus clouds was generally
negative. The models show warmer air moving in aloft off-setting
saturation 850-700mb. 300-850mb RH will fall to around 20 percent
today which would support full sun conditions with just scattered
cumulus.
Sfc high pressure across the cntl/nrn Plains today will move east
into the Midwest tonight setting up south winds and return moisture
across wrn/ncntl Nebraska. The models suggest the potential for
morning stratus across wrn Nebraska Sunday which could linger into
the afternoon as the moisture deepens.
The forecast today through Sunday concerns temperatures and the
forecast leans toward the warmer NBM 50th guidance. A blend of the
short term model blend and the RAP model is in place for highs in
the 60s today, 30s to around 40 tonight and then a modest warm up
Sunday into the 60s to near 70.
A check on the 500m AGL winds Sunday suggested sustained speeds of
25 to 30 mph across wrn Nebraska. Deep cyclogenesis will be underway
across the nrn high Plains. The RAP model suggested gusts of 30 to
40 mph across wrn Nebraska. The wind forecast using the short term
model blend and the NBM 50th came in a bit stronger with gusts of 35
to 45 mph. Given the caliber of the incoming weather system,
potentially record sfc low pressure- sub-980mb across nrn ND and srn
Saskatchewan Monday night according to the NAEFS, the stronger wind
forecast would appear warranted.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 341 AM CDT Sat May 4 2024
Moisture return will deepen Sunday night with strong south winds
of 40-50kts at h850-800mb. The NAM reflectivity product, the
NAM soundings and the RAP model suggest saturation reaching to
800mb which would support drizzle or light showers. POPs for
this feature have been limited to 50 percent but it is worth
noting the h850- 700mb theta e advection will be running strong
across far eastern WY and the Nebraska Panhandle. There is the
potential for an isolated storm or two to fire off the Laramie
range, Cheyenne divide or Pine Ridge late Sunday afternoon which
could drift into wrn Nebraska Sunday evening. Otherwise, strong
capping at h700mb should limit rain chances to just showers or
drizzle.
Attention is drawn to the prospect of an all hazards severe weather
event Monday afternoon generally affecting areas along and east of
highway 83. The upper level forcing in the form of height falls and
an approaching PV1.5 anomaly appear to be quite strong and could
start storm activity as early as 18z-19z Monday afternoon. The focus
will be strong south winds and theta e advection ahead of a Pacific
cold front which should be advancing through wrn Nebraska Monday
morning. Still unknown is the northward extent of the warm sector
opening up across KS into Nebraska.
The warm air advection for this event appears to be aimed at cntl
Nebraska and the day 3 SPC svr wx outlook favors cntl and ern
Nebraska for this and other reasons.
Sub 985mb sfc low pressure will stall and slowly fill across the
nrn Plains Monday night and Tuesday. The occlusion process will
cause the sfc low to reform across the Great Lakes Wednesday. The
models appear to be maintaining the high wind risk mostly across MT
and the Dakotas Monday and Tuesday. The Pacific front Monday could
potentially spread high winds out of WY and into wrn Nebraska.
Otherwise, The early week storm will form a large upper low across
the nrn U.S. which will slowly weaken throughout the week. Subzero
h700mb temperatures will persist across wrn/ncntl Nebraska
throughout the week. The cold air aloft and strong daytime heating
would support afternoon showers and thunderstorms. The NBM suggested
daily rain chances, mainly across nrn Nebraska.
&&
.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1220 PM CDT Sat May 4 2024
VFR conditions are expected to prevail through tomorrow morning
across western and north central Nebraska. Winds shift from
northerly to southeasterly into this evening, and strengthen
tomorrow, with gusts of 25 to 35kts. Low clouds increase
tomorrow morning as well, with the potential for MVFR ceilings
across far southwest Nebraska near the end of the valid period.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Brown
Office: OAX
FXUS63 KOAX 041716
AFDOAX
Area Forecast Discussion
National Weather Service Omaha/Valley NE
1216 PM CDT Sat May 4 2024
.KEY MESSAGES...
- Cooler today and tomorrow, with highs in the 60s and dry
weather expected.
- There is a chance of severe thunderstorms (15 to 30 percent
chance) Monday afternoon and evening.
- Additional chances for showers and storms possible through the
end of the week, but no organized threat for severe storms.
&&
.DISCUSSION...
Issued at 409 AM CDT Sat May 4 2024
Today and Tomorrow:
Water vapor imagery this morning shows a modest troughing over the
far north-central CONUS, with a shortwave extending southward,
pivoting eastward through the largely zonal mid/upper flow that the
base of the trough sits on. A recent surface analysis shows high
pressure moving into northwestern Nebraska behind a cold front that
has helped spark early morning convection moving to the southeast of
the forecast area. KOAX radar imagery this morning features the
continued departure of the MCS/bow that has brought widespread gusts
of 35 to 45 mph, and has struggled to keep up with its own outflow.
A cooler and drier airmass is set to move in behind this convection
and make for a rather comfortable weekend, with highs in the low-to-
mid 60s expected today before only slightly warmer highs settle in
for Sunday in the upper 60s. Winds this afternoon will slowly
diminish from the gusty northwesterly flow this morning and begin
turning southeasterly in anticipation of a stronger storm system to
kick off the work week.
Monday and Beyond:
The main focus of the forecast period comes Monday, when a high-
amplitude and negatively-tilting trough pivots eastward from the
Rockies, shooting a cutoff low northeastward just to the north of
the forecast area. Robust forcing for ascent will be in full effect
by the afternoon hours along a dryline, with convective initiation
expected to occur in central Nebraska. By the time it reaches
eastern Nebraska and western Iowa, a narrow corridor of surface-
based CAPE ranging from 1000-2000 J/kg will provide ample
instability to accompany 0-6 km bulk shear values of 40 to 50
kts or more to allow for an increased probability of severe
storms (up to 30 percent for parts of southeast Nebraska. All
hazards will be possible thanks to the favorable curvature in
the low-level hodograph and combo of strong forcing/sufficient
instability/strong shear, though will take the form of a
line/cluster of storms. This activity is expected to quickly
pivot through the forecast area Monday afternoon and evening,
leaving the area dry by midnight as storms lift north and east.
For Tuesday through the rest of the work week, we'll continue to be
under the influence of the Monday system, which at this point will
be occluded and cut off over the far northern High Plains. The main
mid/upper level jet will be laid over the southeastern edge of the
forecast area, keeping highs from rising much above the mid-to-low
70s with increasing chances for showers and storms returning for
Thursday continuing into the weekend as the occluded system to the
north finally gets slowly pulled away in the mid/upper flow.
&&
.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1211 PM CDT Sat May 4 2024
Low clouds are scattering out this afternoon with skies expected
to become mostly clear. Winds out of the north-northwest gusting
to 25 kt should weaken over the next few hours and continue that
trend through the evening. With light winds overnight and clear
skies, we're a little concerned for fog development overnight
tonight, though none of the forecast guidance is suggesting it
at this time. Will do some more in-depth analysis before the
next TAF package to see if the potential needs to be included.
We'll see winds shift to southeasterly overnight, starting to
increase around 15-16Z which would clear out any fog that might
develop.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...Petersen
AVIATION...McCoy
Office: GID
FXUS63 KGID 041740
AFDGID
Area Forecast Discussion
National Weather Service Hastings NE
1240 PM CDT Sat May 4 2024
.KEY MESSAGES...
- Dry weather expected this weekend with high temperatures in
the 60s and lows in the 30s and 40s this morning and Sunday
morning.
- Another strong weather system will bring increasing chances
for thunderstorms to the area Monday-Monday night. During the
mid-afternoon to late evening hours, there will be the
potential for severe storms...very large hail, damaging wind
gusts, and isolated tornadoes will all be possible.
- Spotty low chances (20-30%) for precipitation continue in the
forecast from Tuesday evening on through the work week, but
confidence remains low at this point.
&&
.DISCUSSION...
Issued at 249 AM CDT Sat May 4 2024
This weekend...
Lingering showers are expected to depart the area to the east
before sunrise today. At the surface, high pressure is moving
into the central and northern Plains this morning with an area
of low pressure over the Pacific coast. The surface ridge will
be present through the weekend, while the surface low and
associated cold front will move over the Rockies by Sunday
afternoon. Aloft at 500 mb, an upper trough with continue
across the Plains today before an upper ridge moves over the
area tonight and Sunday. High temperatures today will be in the
low to mid-60s and just a bit warmer Sunday (in the mid- to
upper 60s). Low temperatures will fall quite a bit under the
ridge. Morning lows this morning and Sunday morning will be in
the 30s and 40s. There may even be some patchy frost north and
west of the tri-cities Sunday morning, but too isolated for any
formal product at this point.
Sunday night through Monday night...
By Sunday night, the low pressure to our west will intensify,
dropping a potent cold front south across the Rockies and
southwestern United States. This will rotate northeast into the
central Plains Monday, enhancing the mid-level jet as it pushes
against a strong ridge over the Great Lakes. Models indicate
thunderstorms potentially initiating over a dryline that is
progged over central NE/KS Monday afternoon. With high CAPE
values (2000+ J/kg, especially over the southern half of the
forecast area as well as along the dryline) and very strong deep
layer shear, severe thunderstorms will be possible Monday into
Monday evening. There is still a question as to how far east
will the dryline manage to be before storms initiate, whether it
is further west in our CWA or farther east (around Highway 281).
Wherever it sets up, the expectation is for very large hail
(possibly 2 inches in diameter or larger) and strong wind gusts
along and east of the dryline, and with higher values of SRH in
the model guidance, a few tornadoes may be possible as well.
Storms will potentially start out as supercells before
developing into a linear system later in the event. Most model
guidance has these storms pushing east of the forecast area by
shortly after midnight Monday night, but the ECMWF has them
linger into the early morning hours Tuesday. Monday will
definitely be a day to keep both eyes on the weather and to have
multiple ways to receive weather warnings.
Tuesday and on...
Tuesday through Friday, the forecast remains overall dry, but
there are a few small chances (20-30%) of precipitation. Behind
the trough Monday, low pressure will rotate northward into
Montana and the Dakotas Tuesday and Wednesday, with another
trough impacting the central Plains mid- to late week, although
the exact placement of the low and associated trough remains
uncertain. Pretty sure the area (or at least some portions of
it) will see some precipitation during this period but
uncertainty as to when remains high.
&&
.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1237 PM CDT Sat May 4 2024
Clear to mostly clear skies are expected to persist throughout
most of the TAF valid period with VFR conditions. A breezy
northerly wind this afternoon will decrease around sunset and
then become more easterly and eventually southeasterly
overnight.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
DISCUSSION...Hickford
AVIATION...Wesely
