109
FXUS63 KOAX 111704
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1204 PM CDT Thu Jul 11 2024

.KEY MESSAGES...

- Dangerous heat is expected for much of the area this weekend
  into Monday, with heat index readings of 100 to 110 degrees
  likely. Sunday and Monday will be the hottest days.

- Could see a few spotty showers and storms tonight and Friday
  night (10-20% chance, highest in northeast Nebraska).

- More widespread storm chances (20-40%) arrive Monday night
  and linger through Wednesday.

&&

.DISCUSSION...
Issued at 345 AM CDT Thu Jul 11 2024

Early this morning a few spotty storms were ongoing along the
NE/KS border on the nose of some moisture transport and along
some low to mid-level frontogenesis. Not expecting these to
amount to much, but one or two could produce some small hail.
Farther north, some patchy fog was developing across portions of
southwest IA. Expect more to develop across much of the area
through sunrise, but it should dissipate rather quickly this
morning. Today should be pretty quiet in the area with guidance
trending away from spotty shower development and even less
cumulus this afternoon. Really most of the "cloud cover" you`ll
see today will be from wildfire smoke, most of which should
remain well above the surface. Otherwise, expect temperatures to
top out in the mid to upper 80s. For tonight into early Friday,
low level moisture transport will ramp up and looks to point
toward northeast NE and extreme southeast NE, leading to some
shower and storm development. Instability and shear look to
remain on the weak side, but there might be just enough for some
elevated small hail producers.

Some notable heat and humidity will start to build in Friday as
the large scale upper level ridge over the western CONUS will
just start to edge into the area. Expect highs in the lower 90s
and dewpoints in the upper 60s to lower 70s to lead to heat
indices near 100 for some locations. Like Thursday, guidance has
trended toward less diurnal cumulus/showers for Friday with a
very stout cap in place. Once again, will likely need to wait
until the overnight/early morning hours on Saturday for any
storm development when low level moisture transport increases
and points into the area.

Attention then turns to increasing potential for dangerous heat
for the weekend as the aforementioned ridge continues eastward
progress and southerly flow continues to usher in warm, humid
air. In addition, area crops are reaching their annual max in
evapotranspiration, further contributing to the humidity. As a
result, expect widespread heat indices in the 100 to 105 range
Saturday. We warm even further for Sunday with NAEFS suggesting
850 mb temperatures in the 90th to 99th percentile of
climatology. While we may not mix quite that high, temperatures
still look to top out in the mid 90s to near 100 with dewpoints
climbing into lower to mid 70s resulting in 105-110 heat indices
for many. A "cold" front will start to push south into the area
Monday, but it won`t be fast enough for much of southeast NE
and southwest IA, where similar heat is expected. Even north of
the front, still expect highs in the lower 90s. With all that
said, we`re firmly in Heat Advisory criteria Sunday and Monday,
and possibly Saturday. Will need to keep an eye on potential
need for an Excessive Heat Watch/Warning as there could be a few
spots that reach a daytime heat index of 110 and stay above a
75 heat index for multiple nights.

By Monday evening, chances increase for storm development along
the aforementioned front. The boundary will move very slowly
south, lingering in the area through Wednesday which will bring
continued shower and storm chances, especially when the low
level jet/moisture transport strengthens at night. By Wednesday,
expect high temperatures to be back down in the lower to mid
80s.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1201 PM CDT Thu Jul 11 2024

VFR conditions persist through the TAF period with broken or
scattered clouds expected at FL200 or higher. Winds will be out
of the southeast, generally below 10 knots through the night
tonight with a slight uptick forecast for Friday.

&&

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

&&

$$

DISCUSSION...CA
AVIATION...Nicolaisen