Forecast Discussion
NWS Omaha/Valley, NE

000
FXUS63 KOAX 270447
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1147 PM CDT Sat Sep 26 2020

...Updated Aviation Forecast Discussion...

.DISCUSSION...
Issued at 250 PM CDT Sat Sep 26 2020

Rain chances for tonight into Sunday and temperatures the next
several days are the primary forecast concerns.

The main features of interest noted from the upper air plots this
morning were the following. At 850 mb a wedge of warm air with
temps of 25C or higher extended from NM and west TX up into KS as
well as the southern and eastern parts of NE. The pattern was
similar at 700 mb with temps of 14-16C in the same area described
for 850 mb. At 500 mb, an area of 12 hour height falls of 50-100
meters extended from southern Saskatchewan down into central and
eastern MT. Fairly strong flow was in place at 300 mb from the
Pacific Northwest into the northern Plains with winds of 90-120
knots.

The mid tropospheric pattern will be changing tonight through
Sunday as a trough develops from south central Canada into the
central part of the Plains. Forcing for ascent is not overly
strong, but there is some mid level frontogenesis. We should see
some showers develop mainly after midnight in northeast NE.

These showers should then spread/develop southeast toward
southeast NE and southwest IA for Sunday. Forecast soundings show
a fairly dry layer below cloud base, which could create locally
gusty winds due to evaporative cooling from the showers.
Instability looks fairly limited, so at least for now will not
mention thunder. Precipitation is expected to become heavier and
more widespread after it gets farther south from eastern MO into
southeast KS. Today (Saturday) will likely be the warmest day for
the next 7 days or more. Highs Sunday are expected to vary from
the upper 60s to the mid 70s, with highs Monday in the 60s.

Tuesday through Saturday...
At the start of this period, the mid level flow will feature a
trough from Manitoba and Quebec down through IL and into LA. A
strong ridge will be located from northern Mexico into the Pacific
Northwest. By Wednesday, the pattern will have changed slightly.
The southern part of the trough will have filled while a closed
low will have intensified over the Great Lakes Region. By Saturday
both the closed low to our northeast and the ridge to our west
will have weakened. Chances for precipitation look pretty low and
temperatures will be cooler than normal next week. Patchy frost
will be possible Monday night, Wednesday night and Friday night.
The highest chance of frost, and possibly some localized freezing
temperatures, will be Thursday night/Friday morning.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1142 PM CDT Sat Sep 26 2020

A cold front has moved through the region with northwest surface
winds behind it. Winds should generally remain under 10 kts
overnight but we do expect speeds to increase to around 15 kts
after Sunday morning sunrise with gusts up to 25 kts possible. A
few showers are possible at KOMA and KLNK from 12-16z as well. VFR
conditions are expected through the TAF cycle.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&

$$

DISCUSSION...Miller
AVIATION...Kern

NWS OAX Office Area Forecast Discussion

Forecast Discussion
NWS Hastings, NE

000
FXUS63 KGID 262356
AFDGID

AREA FORECAST DISCUSSION
National Weather Service Hastings NE
656 PM CDT Sat Sep 26 2020

.DISCUSSION...(This evening through Saturday)
Issued at 256 PM CDT Sat Sep 26 2020

Temperatures today have been held back somewhat due to
increased coverage of smoke and high cirrus. Nevertheless, deep
mixing near and behind the advancing cold front has allowed
temperatures to quickly climb into the 90s in several locations. In
fact, KLXN saw temperatures jump over 15 degrees over the course of
an hour. Therefore, record-breaking highs are still possible at GRI
and HSI today.

Tonight, short term models show a band of light rain developing over
northern portions of the forecast area, mainly after midnight. This
is associated with frontogenetic forcing on the leading edge of the
deep upper trough sinking through the northern Plains. Even so,
QPF amounts are very light, so this will provide no relief from
the drought. Maximum amounts are just a hundredth or two, and most
locations will stay completely dry.

A few sprinkles or light showers may linger into Sunday,
particularly in eastern portions of the area. Cloud cover will
slowly clear, which, along with strong cold air advection, will
keep high temperatures in the 60s and low 70s. A few additional post-
frontal showers could redevelop in the afternoon, but short term
models show the best potential for this remaining across the
Sandhills.

Heading into next week, there is pretty high confidence in continued
dry conditions. The main story will be the cooler pattern, and
possibly a few frosty mornings. Monday will continue to be cold and
breezy as we remain in northwesterly flow behind the upper trough
axis. Some temperatures mid to upper 30s could even creep into
portions of the area Monday night. It still looks like Tuesday
will be a bit warmer and less breezy as the upper trough dives
southeastward and coldest air shifts eastward. Highs are forecast
to return to the 70s across most of the the both Tuesday and
Wednesday.

Another deeper trough is expected to arrive from the north during
the day on Wednesday, bringing another shot of cold and windy
conditions to the area. As a result, highs on Thursday are only
expected to be in the upper 50s and low 60s, and overnight lows may
dip into the low 30s by Friday morning. This has potential to be
our first first widespread frost and potential freeze of the
season.

Beyond that, it looks like temperatures will slowly moderate back to
near normal next weekend, and into the following week. Chances
for any meaningful rainfall remain low, unfortunately.



&&

.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday)
Issued at 648 PM CDT Sat Sep 26 2020

Main issue will be wind gusts directly behind a cold front coming
in the first few hours of the forecast, then wind should diminish
fairly quickly afterwards. Could have some mid-level ceilings with
perhaps some sprinkles, but nothing of huge significance as far as
rainfall is concerned.

&&

.FIRE WEATHER...
Issued at 256 PM CDT Sat Sep 26 2020

The Red Flag Warning continues into this evening. As mentioned
above, we are seeing very deep mixing near/behind the front, and
relative humidities should dip into the 15-20 percent range.
Winds have always been more questionable with this setup. KLXN did
briefly see a 32 MPH gust as mixing peaked, but have since fallen
back below RFW criteria. Therefore, I expect occasional critical
conditions this afternoon and early evening, but it may not be
sustained through the entire period.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Red Flag Warning until 8 PM CDT this evening for NEZ039-040-046-
     047-060>062-072>074-082.

KS...NONE.
&&

$$

DISCUSSION...Mangels
AVIATION...Heinlein
FIRE WEATHER...Mangels

NWS GID Office Area Forecast Discussion