070
FXUS63 KOAX 131732
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1232 PM CDT Sat Jul 13 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.

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

&&

.DISCUSSION...
Issued at 412 AM CDT Sat Jul 13 2024

Today through Monday:

Water vapor imagery this morning features broad ridging over the
western half of the CONUS while broad but low-amplitude troughing
exists over the eastern half. In addition, convective activity has
been sustaining itself over the unusually moist Dakotas into western
Nebraska. Speaking of moisture, a recent surface analysis shows a
surface moisture axis extending from eastern South Dakota/North
Dakota of 70+ dewpoints that reaches trough eastern Nebraska/western
Iowa into Missouri towards Louisiana.

Over the next three days, oppressive heat is expected to build
into the area and will create dangerous conditions for those
outside for extended periods of time. 700 and 850 mb temperature
anomalies for this time of year creep into the top 3%
climatologically this afternoon and peak in the top 1% both
Sunday and Monday according to ensemble situational awareness
tables. This is also backed up by low- level thermal ridges that
slowly move through the area depicted by both the GFS and ECMWF
extending northeastward from eastern Colorado and Kansas. To go
along with the heat, agriculturally-driven evapotranspiration
is kicking into full gear with dewpoints yesterday outperforming
or matching the upper end of guidance -- a trend that is likely
to continue through the next several days before bias-corrected
guidance catches onto the trend. With that in mind, the current
forecast continues to lean on the higher dewpoint guidance and
it bumps up numbers slightly.

With the hot temperatures and increased moisture arriving for the
weekend into Monday, a slew of Heat Advisories and an Excessive Heat
Warning have been issued. Only in parts of northeast Nebraska do you
get relief from the heat Monday as a front pushes south, with that
front potentially exaggerating the heat in the I-80 vicinity. Heat
indices of 105 to 112 degrees are forecast for much of the area
during this stretch, with Sunday and Monday expected to be the
warmest out of the three. If you have any plans to be outside, be
extremely cautious, stay hydrated, and limit your activity.

Some shower and storm activity is possible with the front moving in
Monday, and a strong storm could bring some quarter-sized hail or a
brief downburst for areas of northeast Nebraska east through
central Iowa.

Tuesday and Beyond:

For Tuesday into the latter part of the forecast, we`ll see much
appreciated relief from the dangerous weekend heat with a return to
highs in the 80s and upper 70s through the rest of the work week.
Broad ridging from the weekend is expected to retrograde as ridging
over the Intermountain West increased in amplitude, bringing
northwesterly flow to Nebraska and Iowa. Several shortwaves will be
carried through mid/upper flow, with the two strongest coming
Wednesday evening and then Saturday representing our best bets for
rain during the extended forecast. With or without the rain, this
period should be much more hospitable for outdoor activities and
will feel cooler in comparison to the earlier heat.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1224 PM CDT Sat Jul 13 2024

VFR conditions are forecast through the TAF period with winds
generally out of the south. The winds become light and
disorganized in northeast Nebraska overnight.

The primary concern will be the strong winds at 2000 feet. Have
added some LLWS to the TAFs at OMA and LNK from about 03Z to 12Z
Sunday.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Heat Advisory until 8 PM CDT this evening for NEZ011-012-
     015>018-030>034-042>045-050>053-065>068-078-088>093.
     Heat Advisory from noon to 8 PM CDT Sunday for NEZ011-012-
     015>018-030>034-042>045-050-065-078-088.
     Heat Advisory from noon to 8 PM CDT Monday for NEZ015-033-034-
     042>045-050-065-078-088.
     Excessive Heat Warning from noon Sunday to 8 PM CDT Monday for
     NEZ051>053-066>068-089>093.
IA...Heat Advisory until 8 PM CDT this evening for IAZ043-055-056-
     069-079-080-090-091.
     Heat Advisory from noon to 8 PM CDT Sunday for IAZ043-055-056.
     Heat Advisory from noon to 8 PM CDT Monday for IAZ043-055-056.
     Excessive Heat Warning from noon Sunday to 8 PM CDT Monday for
     IAZ069-079-080-090-091.

&&

$$

DISCUSSION...Petersen
AVIATION...Nicolaisen