-- Discussion containing changed information from previous version are highlighted. --
706
FXUS63 KOAX 192057
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
357 PM CDT Wed Jun 19 2024

.KEY MESSAGES...

-- Changed Discussion --
- Rain chances continue through Saturday and then return to the
  forecast Tuesday and Tuesday night. Isolated occurrences of
  severe weather and/or flooding are possible, especially
  across portions of northeast NE and west-central IA.

- Gradually warming temperatures through the weekend into early
  next week. Heat indices approaching 100 to 105 on Monday and
  Tuesday.
-- End Changed Discussion --

&&

.DISCUSSION...
-- Changed Discussion --
Issued at 323 PM CDT Wed Jun 19 2024

.Tonight into Thursday night:

A prominent mid-level high centered along the mid-Atlantic coast
today is forecast to build west into the OH and TN Valleys,
resulting in building heights across the central Plains. At the
surface, a front extending from northeast MO into southern KS
as of early afternoon is forecast to lift north as a warm front
with that feature moving back into our area on Thursday.

Warm advection associated with the development of a nocturnal
low-level jet is expected to support widely scattered showers
and thunderstorms this evening into tonight across portions of
western and central NE, to the north of the above-mentioned surface
boundary. That activity is expected to spread east/northeast
into our area late tonight into Thursday morning with the
highest measurable precipitation chances across northeast NE.

The duration and coverage of morning precipitation will dictate
the degree of air mass destabilization that occurs Thursday
afternoon along and to the south of the warm front lifting north
into the area. However, it does appear that at least widely
scattered thunderstorm development is possible along the
boundary during the afternoon and evening hours. Model soundings
at peak heating indicate a moist(e.g., PW values of 1.5-1.9")
and moderately unstable environment amidst a vertically veering
wind profile with generally weak vertical wind shear. So, while
organized storm modes aren`t anticipated, locally strong wind
gusts (from wet microbursts) and/or locally heavy rainfall are
possible. Highs on Thursday will range from the upper 70s near
the SD border to mid to upper 80s across southeast NE and
southwest IA.

Showers and thunderstorm chances continue into Thursday night
across northeast NE and west-central IA with the best potential
for heavy rain existing near the SD border.

.Friday and Saturday:

The surface front will remain in the vicinity of the NE-SD
border on Friday where another round of thunderstorms is
possible, especially from mid afternoon into Friday night.
Indications are that the environment will become moderate to
strongly unstable to the south of the boundary and isolated
severe storms are possible near the state line.

On Saturday, the 12z global models are in good agreement in
suggesting that a shortwave trough will progress through the
northern Plains with the above-mentioned front moving back
through our area as a cool front. Best thunderstorm chances will
be across northeast NE and western IA at that time, and some
potential will exist for a severe storm or two.

Forecast highs are in the upper 80s to low 90s on Friday, and
mid 80s to mid 90s on Saturday.

.Sunday and Monday:

A mid-level ridge will temporarily build across the north-
central U.S., contributing to generally dry conditions during
this time frame. Highs in the mid 80s to lower 90s Sunday are
forecast to warm into the lower to mid 90s by Monday with heat
indices approaching 100-105 along and south of I-80.

.Tuesday and Tuesday night:

The models indicate a vigorous shortwave trough moving through
the upper MS Valley with an associated cool front moving into
our area. The front will be the focus for another round of
showers and thunderstorms with some risk for flooding and/or
severe weather. However, specific details remain uncertain at
this time. It will be another hot, humid day ahead of the front
with heat indices of 100-105.
-- End Changed Discussion --

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1225 PM CDT Wed Jun 19 2024

Widely scattered light showers were ongoing as of 12 PM (17z)
across portions of eastern NE and southwest IA with a general
decrease in areal coverage noted over the past couple of hours.
While sprinkles or a brief shower are possible at KOMA and/or
KLNK this afternoon, the forecast will indicate dry conditions
at those two locations through Thursday morning. At KOFK,
showers will become increasingly likely late tonight into
Thursday morning. Otherwise, the main forecast challenge is
timing the onset of MVFR to IFR ceilings at the terminal
locations. Some models suggest the potential for a period of
MVFR ceilings late this afternoon at KOMA and KLNK, which have
been accounted for with a TEMPO group. Greater confidence in
MVFR and eventually IFR ceilings is tonight into Thursday
morning. Finally, winds will transition from northeast to east
or southeast tonight into Thursday morning at generally less
than 12 kt. A brief period of 12+kt winds is possible early this
afternoon at KOMA and KLNK.

&&

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

&&

$$

DISCUSSION...Mead
AVIATION...Mead