St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

262
FXUS63 KEAX 052310
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
610 PM CDT Fri Sep 5 2025

.KEY MESSAGES...

- Chilly tonight into tomorrow morning, with temperatures near
  record lows.

- Pleasant conditions with mostly clear skies and highs in the
  mid to upper 70s for the weekend.

- Warming trend begins next week, with above normal temperatures
  by Wednesday.

&&

.DISCUSSION...
Issued at 219 PM CDT Fri Sep 5 2025

H5 analysis and water vapor imagery shows a deep, closed mid
level low spinning over northern Ontario this afternoon with
accompanying troughing extending southward into the mid
Mississippi Valley (including a 65+ knot mid level jet streak
rounding the base of the trough from Nebraska into northern
Illinois). At the surface, a cold front extends southwestward
from eastern Michigan through the MO Bootheel, curling back to
the west into southern Oklahoma. With just enough forcing and
model soundings showing a relatively saturated mid to upper
troposphere, sprinkles to even some light rain is ongoing across
portions of eastern Kansas into SW Missouri. This will continue
to drift to the east southeast through the remainder of the
afternoon hours and into the evening, and may bring up to one
tenth of an inch of rain to Linn County, KS and Bates County, MO
(with just a trace of rain further north - low levels still
remain dry, so quite a bit of evaporation will occur before
reaching the surface). Other than the light rain, cold air
advection and cloud cover has kept temperatures quite cool this
afternoon. As of 320 PM, the high temp at MCI has only been 65
degrees, which is 1 degree colder than the record low high for
the day of 66 degrees set back in 1905.

By later tonight, drier air will move in, drying out the
atmospheric profile (PWATs falling to around 0.5" to 0.6") with
skies clearing from northwest to southeast. With clear skies,
light winds, and low humidity, conditions will be quite
favorable for strong radiational cooling, allowing for
temperatures to drop into the mid to upper 40s for most
locations (around 50 degrees for the urban core of KC). Record
lows may be threatened, with STJ currently forecast to tie the
record and MCI forecast to remain just a couple degrees above
the record low. Some patchy fog may be possible toward sunrise.

Northwesterly mid level flow takes hold tomorrow on the
southwestern periphery of the mid/upper trough from eastern
Canada into the Great Lakes region and east of a ridge building
over the western CONUS, with surface high pressure building in.
Subsidence will keep skies mostly clear, with high temperatures
reaching the mid to upper 70s. Similar conditions are expected
for Sunday, although with the western ridge further impinging on
the region yielding mid level height rises, temperatures for
Sunday afternoon will likely be a couple/few degrees warmer.

The warming trend continues into next week as the western upper
ridge noses further eastward, with highs warming into the low to
mid 80s for Monday afternoon, along with some modest moisture
return as low level winds turn southerly (dew points increasing
from the mid to upper 40s into the mid 50s). A shortwave trough
embedded along the eastern edge of the ridge is progged to
approach the region Monday night into Tuesday, which will allow
for a chance for isolated showers and thunderstorms overnight
Monday into early Tuesday.

As we head into mid to late week, global models suggest the
upper ridge becoming more highly amplified, with the ridge axis
shifting eastward and becoming centered over our region by
Thursday. This would bring even warmer temperatures, with highs
in the mid 80s to near 90 degrees currently forecast for Wed and
Thurs afternoons.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 607 PM CDT Fri Sep 5 2025

Mainly VFR conditions are expected for the next 24 hours, with
skies rapidly clearing this evening. There is a chance for some
localized sub-VFR in fog near daybreak, especially at STJ.
However, chances are generally too low (~10%) at the KC
terminals for inclusion in the TAFs at this time. Any fog should
dissipate quickly after sunrise. Winds will become light west or
southwest overnight, perhaps becoming calm or light/variable. A
west wind around 10 kt should develop by Saturday afternoon.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...None.
KS...None.

&&

$$

DISCUSSION...Williams
AVIATION...CMS