St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

071
FXUS63 KEAX 061117
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
617 AM CDT Sun Oct 6 2024

.KEY MESSAGES...

- Elevated fire weather concerns today due to potential for
  gusty conditions in combination with low relative humidity.

- Cooler conditions expected today, though temperatures remain
  above-average.

- Dry conditions prevail through the next 7 days.

.DISCUSSION...
Issued at 306 AM CDT Sun Oct 6 2024

The amplified closed low centered over northern Ontario continues to
dig into the Great Lakes region this morning, lowering H500 pressure
heights over Minnesota, Wisconsin, and Michigan. This low pressure
system will not bring any impacts to the forecast area. Closer to
the surface, the associated lower-level cyclone and cold front will
turn the southwesterly prevailing flow northerly. In the late
morning hours today, a surface high builds across Kansas, with its
center expected to meander east through that state for the duration
of the day. The proximity of this anticyclone to our area will
induce sinking motions that will inhibit potential for condensation
aloft and thus will result in the lack of cloud cover.

Breezy conditions from the aforementioned northerlies are forecast
for today due to the surface pressure gradient tightening with a
high pressure to our west and low pressure to the northeast.
Glancing at the probabilistic wind forecast, the HREF ensemble
indicates a near certainty (80%-100%) that areas in northwestern
Missouri, including St. Joseph, will experience wind gusts over
20mph starting around 14Z and extending through 19-20Z. This
particular ensemble does also show lower chances (though still up to
70%) of relative humidity values bring less than 25% (which is the
threshold for headlines) for the previously mentioned portions of
the region throughout the late morning and afternoon hours.

Comparatively, the NBM-CONUS ensemble gives the highest chances
(>75%) for wind gusts greater the 20mph alongside relative humidity
values less than 25% for northwestern Missouri, specifically
Atchison and Holt counties in the afternoon hours. The gridded
forecast is less bullish, indicating wind gusts over 15mph being
possible after 15Z in northern and central portions of the forecast
area. Dry conditions are once again highlighted in the gridded
forecast as well, with relative humidity values mostly in the 20-30%
range for the entire County Warning Area (CWA) through the
afternoon. So, fire weather concerns will still be elevated today
though winds are not as strong in relation to Saturday (though low
relative humidity is something to take account of). Also, aligning
with probabilistic datasets, forecast soundings showcase the
strongest winds that could potentially mix down toward the surface
are in the 20-25mph range this afternoon.

Afternoon highs are forecast to be cooler than yesterday, with
temperatures in the low to mid 70s north of I-70 and warmer (upper
70s) south of the I-70. Overall, these high temperatures are above-
normal for this time of year. The robust upper-level ridging
prevalent in the desert southwest is responsible for these spring-
like conditions, along with the persistently quiet weather pattern
in the synoptic scale. The ridge axis of this high pressure system
in the western CONUS will progress eastward throughout the workweek.

For tonight, temperatures will be near to below-normal (low to mid
40s) as the center of the surface high mentioned earlier continues
to be the main influence on ambient conditions. Otherwise, the
dominance of this broad anticyclone will result in the afternoon
highs being above average in the short-term, especially for western
portions of the region. Additionally, the vertical continuity of the
upper-level ridge axis and lingering lower-level anticyclone will
produce a stable atmospheric profile, characterized by mostly clear
conditions for the foreseeable future.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 616 AM CDT Sun Oct 6 2024

VFR conditions will prevail through the period with mostly clear
skies forecast. North-northwesterly winds reaching up to 15 knots
are expected during the daylight hours. Gusts over 20 knots are
possible, especially at STJ. Winds should relax after sunset as
diurnal mixing ceases. An easterly shift in the wind is
anticipated overnight.

&&

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

&&

$$

DISCUSSION...Hayes
AVIATION...Hayes