648
FXUS63 KOAX 091136
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
636 AM CDT Thu May 9 2024

.KEY MESSAGES...

- Scattered showers and isolated thunderstorms are expected
  across the region today bringing a 20 to 40 percent chance of
  rain at any given location. No severe weather is expected.

- Several rounds of showers and thunderstorms are forecast Sunday
  through Wednesday. Current indications for the greatest
  precipitation chances of 50-60%, are expected Sunday night and
  Monday afternoon. No severe weather is expected.

- Slightly above normal high temperatures in the middle 70s to
  lower 80s this weekend, and again the middle of next week.

&&

.DISCUSSION...
Issued at 340 AM CDT Thu May 9 2024

Today and Tonight...

An elongated upper level trough extends from essentially from
the North Atlantic to the western U.S. The western U.S.
anchoring upper level low disconnects during the day today,
leaving a closed upper low over the intermountain region of the
West. The forecast area will remain under the influence of the
cyclonic shear side of the trough today through late evening.
Convergent moist, isentropic flow will persist At the surface a
surface trough will move southward across the area. The combined
effect will be scattered (10-30% coverage) showers. Diabatic
effects will allow for isolated thunderstorms during the late
afternoon and early evening. Precipitation totals of only a few
hundredths, with isolated amounts of one or two tenths where
thunderstorms occur, are expected. Temperatures today will be
slightly cooler (60s) due to low level cold advection and
evaporative cooling. Overnight temperatures generally will be in
the 40s.

Friday and Saturday...

Generally dry conditions are expected, though a shortwave
dropping southward from Manitoba/Ontario into the Ohio Valley
Friday afternoon may bring portions of western Iowa and extreme
eastern Nebraska isolated showers and thunderstorms. Most areas
will remain dry. West to northwest winds 15 to 20 mph will
gusts 20 to perhaps 30 mph on Friday. A nice day is expected for
Saturday with sunshine, light winds and temperatures in the
upper 70s.

Saturday Night through Wednesday...

The closed low over the intermountain region moves slowly east
southeast across the central and southern plains. Sharpening the
wind field. Large scale isentropic ascent ahead of the system
will draw moisture northward from southern Texas across the
southern High Plains with models indicating saturation H8-H7 by
Saturday night. The attendant surface system will be Oklahoma
and Texas, with an inverted trough extending into the northern
plains. As forcing mainly will be from the mid-levels, expect
any storms that develop to be elevated. The better shear and
instability will reside across the southern plains, thus expect
only general thunderstorms. The wave moves into the southeast
U.S. by Tuesday, but is followed quickly by another shortwave
diving southeast across the plains Tuesday night into Wednesday.
Mass field response appears limited, as low level moisture
return appears questionable. Though cooling mid-levels appear
enough to decrease lapse rates. As such, better chances for
stronger storms by Wednesday.

High temperatures will remain above normal through the period,
with highs near 80 by Tuesday.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 630 AM CDT Thu May 9 2024

VFR conditions start out the period with northwesterly winds in
place at 10 kts or less. Main concern of the forecast is the
potential for MVFR ceilings developing mid-to-late morning at
FL015 to FL030 as clouds develop and move in from the north,
with showers becoming a possibility during the afternoon (but
generally less than a 30% chance). As of right now, it looks
like a period of broken clouds will be in place at KOMA but
have kept the time limited until we see it beginning to develop.
Gusts of around 20 kts will develop this afternoon as well, but
will quickly drop off by the evening hours.

&&

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

&&

$$

DISCUSSION...Fortin
AVIATION...Petersen