Forecast Discussion
NWS Omaha/Valley, NE

000
FXUS63 KOAX 212335
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
635 PM CDT Thu Oct 21 2021

...Updated Aviation Forecast Discussion...

.DISCUSSION...
Issued at 256 PM CDT Thu Oct 21 2021

This evening - Tonight:
Low stratus is slow to erode over parts of the central and eastern
portions of the forecast area. Expect that low stratus will
persist over eastern portions of the area for a while longer.
Surface high pressure is building into the region with the ridge
axis over eastern Nebraska tonight. This will cause winds to
become light and variable. Temperatures are a concern tonight,
with overnight lows dipping below freezing for northern portions
of the area and frost a concern for southern portions. Some things
to watch though is cloud cover...there will be periods of time
where high clouds will move over. The first wave will be from the
west and move across the area this evening before causing mostly
clear skies for around and after midnight. Then again near sunrise
some mid-level cloud cover will be present moving in from the
northwest as a disturbance dive southeast. So there will be
periods of clear skies with light winds and maximum radiational
cooling and then periods where cloud cover will keep it a bit
warmer. Overall, not much change to the overnight low forecast.
Generally along and north of I-80 will see at or below 32 degrees.
The disturbance early Friday could cause some light precipitation,
but feel the best chance for it will be just north of the forecast
area, so the forecast is currently dry.

Friday - Sunday:
Temperatures will rebound tomorrow with highs in the 50s to 60s
for most areas, warmest to the west and south where cloud cover
from the aforementioned disturbance early Friday will keep maximum
insolation at bay.

Saturday will be mild, with weak ridging building in overhead. But
warm air advection ahead of the next disturbance moving over the
intermountain west will bring showers and thunderstorms to the
area Saturday night into Sunday. Some of these storms could be
strong to marginally severe, especially for areas along and south
of I-80. The moisture availability is confined to those locations
causing a sharp gradient in available instability.

A surface low will track across Kansas and into Northern
Missouri/southern Iowa. Precipitation amounts will be highest
the farther east and south you go.

There are some discrepancies about how strong this disturbance is
as it moves overhead. A stronger system could have more widespread
precip and stronger winds.

The cold front will move through Sunday afternoon causing some
locations to be warmer early afternoon than late afternoon after
the passage.

Monday - Wednesday:
The remainder of the forecast is active with another system moving
through mid week. After a cooler Monday, temps will rebound to
near to slightly normal (Normal is the low 60s). There are
discrepancies with this system in how strong and deep it will be.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 630 PM CDT Thu Oct 21 2021

VFR criteria to prevail for the TAF period. Low clouds over KOMA
should clear the area by 01Z. Winds expected to be under 10 kts
for the TAF period. A slow wind shift is expected to take place,
with winds expected to be southeasterly by tomorrow afternoon.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Freeze Warning from 1 AM to 10 AM CDT Friday for NEZ015-031>034-
     042>045-050.

     Frost Advisory from 1 AM to 10 AM CDT Friday for NEZ051>053-
     065>068-078-088>093.

IA...Freeze Warning from 1 AM to 10 AM CDT Friday for IAZ043-055-056.

     Frost Advisory from 1 AM to 10 AM CDT Friday for IAZ069-079-080-
     090-091.

&&

$$

DISCUSSION...Billings Wright
AVIATION...Fajman

NWS OAX Office Area Forecast Discussion

Forecast Discussion
NWS Hastings, NE

000
FXUS63 KGID 212323
AFDGID

AREA FORECAST DISCUSSION
National Weather Service Hastings NE
623 PM CDT Thu Oct 21 2021

...Aviation Update...

.DISCUSSION...(This evening through Thursday)
Issued at 352 PM CDT Thu Oct 21 2021

It`s been a nicer day across the area today compared to yesterday,
especially regarding the winds. Upper air and satellite data show
continued northwesterly flow in place across the region, set up
between ridging extending through the Great Basin/Rockies areas
and low pressure spinning over Ontario, with an embedded more
compact disturbance sliding through the the Great Lakes. At the
sfc, the pattern across the CWA is weak thanks to a ridge of
higher pressure draped through the region, keeping winds on the
lighter side. Most locations have a more variable wind direction,
winds across eastern areas are northwesterly. Low level stratus
started out the day anchored over the ENErn third of the CWA, but
dissipated by late morning. Satellite imagery showing a batch of
mid-upper level clouds now streaming into the area from the
northwest. Temperatures today have worked out well, still looking
at highs reaching the mid 50s to mid 60s.

Tonight through Friday night...

Overall, no significant changes were made to the forecast for this
time frame, which remains dry. Models showing no notable shift in
the northwesterly upper level pattern across the region. The
primary concern will be with frost potential, mainly tonight-early
Sat AM.

The batch of mid-upper level cloud cover currently moving in is
expected to continue pushing southeast the rest of this afternoon-
evening, with sky cover by mid-late evening becoming mostly clear-
clear. Plenty of sun is expected as we get into Friday, with the
potential for a bit more cloud cover through the Fri night-early
Sat AM hours.

This sfc pattern is expected to remain on the weak side through
tonight, keep winds light, but gradually turning more southerly
with time as the main ridge axis slides east. Models show winds
turning more easterly with time on Friday, especially across our
Neb. counties, as low pressure deepens over the CO/NM border area.
Winds across our KS counties may be more variable, will be
dependent on where a weak sfc warm frontal boundary/trough axis
sets up.

For late tonight, the combo of clearing skies, lighter winds and a
cooler/drier air mass in place will be favorable for the
development of frost, with some locations getting close to that
`hard freeze` mark of 28 deg. Made no changes to the inherited
Frost/Freeze headlines. Forecast lows remain on the cold side of
models/guidance, with low-mid 30s in the Frost Adv area, and right
around 30 in the Freeze Warning counties of
Howard/Nance/Merrick/Polk.

Expecting a bump up in highs for Friday, making it an even nicer
day than today. Current forecast highs are in the low-mid 60s in
the far northeast to low-mid 70s in the southwest. While not
expected to be as cool as tonight, can`t rule out the potential
for more frost early Sat AM, mainly along/north of I-80.

This weekend...

The daytime hours on Saturday remain dry, with models showing
increasing precipitation chances starting Saturday evening and
continuing through Sunday...but some uncertainties with exactly
how things evolve remain, esp. Sunday. Weak upper level
shortwave ridging pushing through the Plains will bring more zonal
flow for a bit during the day on Saturday, before turning
southwesterly as a trough axis moves through the Plains. During
the evening/overnight hours Saturday, lift/warm air advection
ramps up, thanks to an increasing LLJ. Models are in pretty good
agreement showing the main corridor of the jet around 45-50kts,
but the better lift looks to be focused more over eastern KS/NE.
At this point our CWA is still looking to be on the WNWrn fringe
of the better lift, but certainly can`t rule out thunderstorm
activity affecting us. Forecast PoPs are in the 40-60% range,
mainly for areas along/east of HWY 281. Can`t rule out a few of
those storms being strong/severe with better shear/instability
expected to be present, and southeastern areas are included in the
SPC Day 3 Marginal Risk area. Hail would be the primary threat.

As we get into Sunday, increased lift via that LLJ pushes off
further to the east, with precipitation chances then driven by the
upper level disturbance passage itself. There are some notable
difference in models with its evolution...is it more of a
progressive/northern similar to the NAM/GFS, not bringing much QPF
to anywhere but northern portions of the CWA...or will it be
closer to the ECMWF, which continues to show a stronger more
southern development of a closed low, bringing the potential for
more widespread QPF to the CWA. Confidence is not high in PoPs at
this point for Sunday. Forecast highs Sat/Sun have plenty of 60s,
but similar to PoPs, confidence is not high.

Monday through Thursday...

The forecast dries back out for Monday and most of Tuesday, before
another upper level system bring the next shot of precipitation to
the region. PoPs are currently on the low side late Tuesday into
Wednesday AM, mostly 20% chances, as some notable model
differences exist with the strength/track of this system. Temps
may rebound back into the 60s/70s for Tuesday ahead of this next
system, with low-mid 60s for Wed/Thur.



&&

.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday)
Issued at 620 PM CDT Thu Oct 21 2021

High clouds will move out of the area to the east this evening.
There is an outside chance for some fog to develop, but higher
probability for this remains across eastern Nebraska. Therefore
have just included 6SM BR at GRI for now.

Winds will be light and variable tonight, with light south to
southeasterly winds for most of Friday.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Frost Advisory from 1 AM to 10 AM CDT Friday for NEZ061>064-
     073>077-082>087.

     Freeze Warning from 1 AM to 10 AM CDT Friday for NEZ041-047>049.

KS...Frost Advisory from 1 AM to 10 AM CDT Friday for KSZ005>007-
     017>019.

&&

$$

DISCUSSION...ADP
AVIATION...Mangels

NWS GID Office Area Forecast Discussion