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102
FXUS63 KOAX 071837
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
137 PM CDT Mon Jul 7 2025

.KEY MESSAGES...

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- Line of strong to severe storms expected this evening. Primary
  hazard: damaging winds (70+ mph). Hail, brief tornado, and
  heavy rainfall also possible.

- Additional chances for storms through the rest of the work
  week, with Thursday night looking like our next best chance
  for severe weather.

- Drier, milder weather possible next weekend.
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&&

.DISCUSSION...
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Issued at 137 PM CDT Mon Jul 7 2025

Right now across our area we`re seeing partly cloudy skies with
hazy conditions aloft, likely from a high smoke layer out of
western Canada. Vis satellite shows a fairly active cu field
across our area indicating a significant amount of instability,
which models predict to be around 2000-2500 J/kg. This sets us
up for potential severe weather this evening as an MCS is
forecast to drop south out of eastern South Dakota, bringing a
fairly good damaging wind threat as well as a low hail and
tornado threat.

In water vapor imagery, you can see the approaching shortwave
over central South Dakota this afternoon. This is expected to
trigger storms across southeast South Dakota sometime between
3-5 PM. These storms will then congeal, feeding off an ample
amount of environmental CAPE to produce a broad MCS that will
drop south across our area tonight. While CAMs indicate
uncertainty in storm initiation time, based on current
observations we would lean towards later arrival times for
storms, more likely seeing storms move into northeast Nebraska
between 6-7 PM, arriving in the Omaha Metro around 10-11 PM.
While environmental shear isn`t remarkable, the orientation of
0-3km shear vectors indicates potential for a brief spin-up or
two (tornadoes), which will be closely monitored. As the MCS
progresses southward, it will be moving into an environment of
weaker shear, which likely won`t support this system maintaining
it`s strength lending toward a weakening trend as the line
progresses southward.

One additional hazard we will be monitoring is the potential for
locally heavy rainfall, especially in the later stages of the
MCS. PWAT values will be ranging from 1.5 to 1.75 across eastern
Nebraska and western Iowa, lending toward efficient rain-
producing storms. For the most part, storms should be moving
well enough to keep from getting heavy enough rainfall totals
for flooding, but as the MCS weakens and slows down we may see
the boundary stall across southeast Nebraska/southwest Iowa.
This could lead to storm training along the boundary and locally
higher amounts in this area.

Tuesday, a meso-high will be in place through most of the day as
the atmosphere will be well worked-over from overnight storms.
This should keep conditions dry. Temperatures will warm into the
mid-to-upper 80s, with dew points in the upper 60s to low 70s
making it feel muggy.

For the second half of the week, the upper-level pattern remains
active with a ridge over the Desert Southwest creating
northwesterly flow across Nebraska and the Central Plains. This
pattern is conducive for MCS development in the summertime,
especially with a good enough moisture tap via the diurnal low-
level jet, pulling in moisture from the Gulf each evening. This
pattern remains in place through the end of the week, with our
next MCS forecast for Wednesday night into Thursday morning
(20-30% chance), and a higher chance for another MCS Thursday
night into Friday(50-60% chance). WPC is already highlighting
the Thursday night-Friday morning timeframe with a Slight Risk
for excessive rainfall, due to the west-east orientation of the
surface boundary, orthogonal to the low-level jet. This
supports the potential for training storms with heavy rainfall.
Temperatures through the end of the week will remain fairly
steady with highs in the 80s and lows in the 60s to low 70s.

Rain chances drop off Saturday and Sunday as we see the ridge
over the Southwest retreat westward over the Coast of
California. This will shift the storm track further south and
bring in milder temperatures. Highs may only get into the low
80s on Saturday, though we see them warm back up into the upper
80s going into Sunday.
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&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1158 AM CDT Mon Jul 7 2025

VFR conditions through this afternoon under partly cloudy skies,
with cigs staying elevated. Winds are out of the east or
southeast across our area, becoming more southerly with time. A
line of storms will approach from the north this evening with
strong to severe northerly winds possible in excess of 50kt as
they arrive. Window of arrival for KOFK is around 23-02Z, 01-04Z
at KOMA, and 02-05Z at KLNK. Storms should be weakening as they
travel south, with best chance for severe winds at KOFK. Expect
a shift to northerly winds once the line moves through with
additional showers and storms possible for a few hours after the
leading line moves through. Winds should remain predominantly
out of the north through Tuesday morning, though they could
become variable at times, staying 5 kt or less.

&&

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

&&

$$

DISCUSSION...McCoy
AVIATION...McCoy