Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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684
FXUS63 KEAX 191122
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
622 AM CDT Thu Oct 19 2017

.Discussion...
Issued at 333 AM CDT THU OCT 19 2017

Operational models remain consistent and as such very little change
has been made to the forecast. With southwesterly flow becoming
established and the forecast area residing in a broad warm sector,
the warm temperatures already experienced this week will continue
for the next three days. Afternoon readings will comfortably reach
the 70s each day, some 10-15 degrees above normal. Weather-wise, a
strong pressure gradient will develop across the Plains states on
Friday into Saturday with surface high pressure anchored over the
Appalachians and a lee trough forming over the High Plains. This
will bring breezy conditions on Friday and Saturday, along with an
increase in moisture with dewpoints returning to the 60s by
Saturday. Scattered showers and isolated thunderstorms will be
possible by late Friday night into Saturday morning as a 50 kt, H85
low-level jet and insentropic ascent materialize over the forecast
area. The main focus will be on a cold front as it sweeps through
the area late Saturday afternoon and evening, corresponding to
widespread showers and thunderstorms. With strong linear forcing and
upper ascent in place, confidence is growing that a squall line will
develop during the mid to late afternoon hours over far northwest
Missouri into eastern Kansas. While the greatest reservoir of
instability will be located to the southwest of the forecast area in
southeast Kansas into Oklahoma, sufficient instability is anticipated
to be in place to support convection in the strong shear
environment. The degree and geographic corridor of instability will
be later determined by the amount of destabilization that can
occur, especially with some potential of pre-frontal showers and
thunderstorms during the day on Saturday. That said, vertical wind
shear will be more than sufficient to support robust convection, and
the strong near-unidirectional wind fields and linear nature of
convection yields some concern for damaging wind gusts. Currently,
the greatest threat for severe storms is across the southwestern
half of the CWA.

The cold front will push through the CWA Saturday night, with some
lingering post-frontal precipitation during the overnight hours.
Still, the progressive nature should clear rain out of the area
before or shortly after sunrise Sunday for most areas, with clouds
clearing and a return of the sun by midday Sunday. Cooler and drier
air will advect into the region, with another reinforcing shot by
Tuesday as a large upper trough amplifies and digs into the
central/eastern CONUS. The end result will bring back high
temperatures closer to seasonal averages.

&&

.Aviation...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 610 AM CDT THU OCT 19 2017

VFR conditions are expected through the period, outside of shallow
river fog slated to impact STJ for the next few hours. Southerly
winds will prevail, with some concern for LLWS overnight.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&

$$

Discussion...Blair
Aviation...Blair



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