278
FXUS63 KOAX 052239
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
539 PM CDT Sun May 5 2024

.KEY MESSAGES...

- Low clouds move in overnight tonight with south- southeasterly
  winds increasing Monday morning. Wind Advisory issued for
  northeast Nebraska for 10 AM through 7 PM Monday.

- Potentially strong storms are expected Monday evening,
  primarily from 4 to 10 PM as a line of storms moves thought
  the area. Damaging wind, hail, and embedded tornadoes are
  possible.

- Light showers and a few rumbles of thunder linger through the
  end of the work week, with drier conditions and highs in the
  70s returning for the weekend.

&&

.DISCUSSION...
Issued at 329 PM CDT Sun May 5 2024

This afternoon - Monday Night:
We`re seeing high clouds stream up this afternoon from the
surface low down over north-central Texas. Otherwise,
southeasterly winds are making for a pleasant day with highs in
the mid 60s. Only thing that would make it better would be if it
were in the 70s.

We have an upper-level trough that has moved onshore out on the
West Coast that will be responsible for our chance for severe
weather tomorrow evening. Right now we are watching the
preceding shortwave trough which is developing the area of low
pressure across the lee side of the Rockies this afternoon.
We`ll see increasing winds out out of the south-southeast across
central Nebraska overnight associated with this developing
system and the strengthening pressure gradient across Nebraska.
The stronger winds will reach eastern Nebraska Monday morning,
when we see winds start to really ramp up between 7 and 10 AM.
Strongest winds tomorrow will be in northeast Nebraska where we
could see wind gusts as high as 50 mph, so we have issued a Wind
Advisory for this area from 10 AM to 7 PM.

Now for the severe storm potential. Overnight tonight we`re
going to see low clouds spread across eastern Nebraska and
western Iowa associated with the surge in moisture being
advected in by the low-level jet out ahead of this developing
surface low. This may provide a failure point for the severe
potential tomorrow as there is some question about when we will
see this widespread cloud cover clear out Monday afternoon. If
it holds together most of the day, it would limit how much the
environment will be able to destabilize during the afternoon
ahead of the dry line moving through which would weaken any
storms that may move through during the evening. Right now,
high-resolution convective-allowing models do not show this to
be the case, but our lower-resolution, synoptic models are the
ones holding on to the cloud cover longer into the afternoon. It
will certainly be something to watch.

Convective mode certainly seems likely to primarily be some form
of Quasi-linear convective system, meaning a line of storms
along the dry line, with the possibility of a few discrete
storms out ahead of the line of storms. The greatest amount of
low-level instability will likely be found across southeast
Nebraska south of I-80, where the Storm Prediction Center has
the Enhanced Risk drawn up. However, with how potent this system
is, don`t rule out the rest of the Slight Risk area across
eastern Nebraska and western Iowa. We will have a strong QLCS
moving across eastern Nebraska into Western Iowa, from around 4
PM to 10 PM, with the potential for large hail, damaging winds,
and embedded tornadoes. 0-6km bulk shear vectors are oriented
normal to the line of storms, so we`ll have to monitor closely
any bowing segments for potential circulations that may develop.

Tuesday-Wednesday:

Once this system moves through, we see a broad upper-level
trough set up across much of the Inter-Mountain West, putting us
in a fairly baroclinic regime with another chance for showers
and thunderstorms, albeit weak, Tuesday night into Wednesday.
Highs on Tuesday will be in the 70s but drop back down into the
60s on Wednesday.

Thursday - Saturday:

Models are less confident in the pattern shift late in the week
than yesterday, though they still show a cooler, showery pattern
going into the weekend. Drier, warmer weather looking possible
to return Saturday and Sunday.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 530 PM CDT Sun May 5 2024

VFR conditions will prevail this evening as southeasterly winds
calm under 12 kts at KOMA and KLNK by 02-03Z. Wind will increase
in speeds again around 08-10Z as a deck of clouds with MVFR
ceilings moves in from the west. Drizzle or light showers are
possible (20% chance) overnight. A period of IFR ceilings is
expected at KOFK through the late morning with low confidence
in this impacting KLNK and KOMA.

MVFR ceilings will persist throughout much of the day with
gradual breaking and improvement possible later in the
afternoon (16-20Z). Southeasterly winds will remain strong
through the day with gusts up to 36 kts possible. A line of
thunderstorms with severe potential will move from west to east
across the terminals in the final hours of the forecast period.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Wind Advisory from 10 AM to 7 PM CDT Monday for NEZ011-012-
     015>018-031>034.
IA...None.

&&

$$

DISCUSSION...McCoy
AVIATION...Wood