913
FXUS63 KOAX 070408
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1108 PM CDT Tue May 6 2025

.KEY MESSAGES...

- Rain and some thunder returns Wednesday afternoon and evening
  with chances peaking at 20-30%. Rainfall amounts will be light
  with most seeing a few hundredths of an inch.

- A few showers may linger into Thursday (20-30%) before exiting
  in the evening.

- Warming trend continues for the weekend into next week with
  highs in the mid to upper 80s with little chance (<5%) for
  rain.

&&

.DISCUSSION...
Issued at 220 PM CDT Tue May 6 2025

.SHORT TERM.../Today through Wednesday Night/

The omega pattern continues to influence our weather across portions
of the Central and Northern Plains this afternoon. 19z 500 mb
RAP objective analysis depicts the southwest US closed low
centered over New Mexico, while the eastern US low is now based
over eastern Ohio/western Pennsylvania. Much of the Northern and
Central Plains remain underneath the upper level ridge, whose
axis now extends from the Dakotas southeastward toward Missouri.
At the sfc, RAP objective analysis shows a low across eastern
Ontario with a weak frontal boundary extending southwest toward
Minnesota, eastern South Dakota, and portions of northern
Nebraska.

Will continue to see high based clouds increase in coverage across
the forecast area this afternoon as the closed 500 mb low pivots
over New Mexico and ejects northeast. 19z radar imagery is
already showing a band of light rain associated with this
feature over the southern half of Kansas. This activity
continues to move northward, but should hold off from entering
our forecast area until at least Wednesday morning. Some CAMs
try to bring showery activity across our far south after 00z
this evening, but BUFKIT soundings show a large amount of dry
air in the midlevels these showers will need to overcome, so
expecting dry conditions for the evening hours. So, aside from
seeing increasing cloud cover from the south, this afternoon and
evening should be fairly pleasant, with highs reaching the low
80s north to upper 70s along and south of Interstate 80.
Easterly winds will be somewhat breezy, around 10-15 mph with
gusts up 20 mph resulting from the approaching disturbance. Lows
tonight will be in the low to mid 50s.

By Wednesday morning and afternoon, better 1000-850 mb moisture
transport arrives from the Gulf region which will help overcome any
lingering dry air. QG forcing will also increase throughout the day
as the closed low advances toward southern Kansas, with the
strongest forcing in the OAX forecast area still expected mainly
south of Interstate 80 and toward the Kansas border. These factors
will result in a gradual increase of scattered showers mainly
along and south of a line from Boone to Madison to Wayne
Counties. PoPs peak at 20-30% in the afternoon over our far
south were the best forcing is.

Of interest is how CAMs try to generate a broken line of showers and
thunderstorms mainly north of Interstate 80 during the late
afternoon/early evening hours resulting from weak convergence
along the sfc boundary mentioned earlier. It is worth noting
that CAMs show differences with the location/placement of the
frontal boundary. However, with weak MUCAPE at around 100-200
J/kg at best, poor shear, and poor lapse rates, not expecting to
see severe weather with this activity. Showers and a few
thunderstorms will linger through the evening hours (15-20%).
Rainfall totals for this event remain fairly light at around a
tenth of an inch at best if caught underneath a storm, but most
locations only see a few hundredths. Highs Wednesday will be a
tad cooler in the upper 70s north to low 70s south with breezy
easterly winds. Lows will be in the upper 40s to mid 50s.

.LONG TERM.../Thursday through Monday/

Thursday will see the 500 mb low depart southeast into southern
Missouri and attempt to phase with a longwave trough ejecting
southward over the eastern US. Portions of the forecast area will
still be under the influence of cyclonic flow with some lingering
vorticity, so may see some lingering showers Thursday (20-30% PoP)
before exiting in the evening. Highs Thursday warm near 80F across
the far north with mid 70s elsewhere due to lingering cloud cover

As we head into Friday and the weekend, will see an amplifying 1000-
500 mb thermal ridge across the western US gradually move eastward
into the Central and Northern Plains. This will result in highs
warming into the low to mid 80s by Saturday, and mid to upper 80s by
Sunday and Monday. The ridging pattern will also help suppress
PoPs through Monday.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1108 PM CDT Tue May 6 2025

VFR conditions will prevail through the forecast period with
BKN-OVC clouds at FL200-250 overnight lowering to FL100-150 on
Wednesday. Model soundings indicate some potential for SCT-BKN
clouds at FL040-050 on Wednesday afternoon. Winds will oscillate
between east-northeast and east-southeast at less than 12 kt
into Wednesday morning. Speeds could increase to 12-13 kt with
gusts to 20 kt by afternoon. Finally, the models continue to
show the development of isolated to widely scattered showers
and/or thunderstorms late Wednesday afternoon into evening,
mainly north of I-80. Given the low confidence in occurrence at
either KOFK or KOMA, no mention will be made in the forecast.


&&

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

&&

$$

DISCUSSION...Castillo
AVIATION...Mead