Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
FXUS63 KEAX 180519
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1219 AM CDT Thu Sep 18 2014
Issued at 855 PM CDT WED SEP 17 2014
Have gone dry over all but the far southwestern CWA to align with
ongoing convection just south of the CWA and upstream accas/elevated
convection approaching. Have also added fog over the CWA after
midnight. Clouds have cleared out across much of the CWA and setting
up for good radiational cooling with very light winds despite
advecting in drier air from the east. Fog has started to form just
east of Kansas City. Latest SREF visibility prog and UPS fog output
also suggest potential for dense fog forming. Will monitor visibility
trends as there is just as much of a chance for low stratus to form
vs dense fog.
.SHORT TERM...(This Evening through Thursday Afternoon)
Issued at 310 PM CDT WED SEP 17 2014
For much of the CWA the low clouds have been hanging tough with slow
erosion on the northern edge. This has resulted in highly variable
temperatures ranging from the mid 60s to lower 70s. Further west in
KS lies a warm front with upper 80s to low 90s and very humid air.
That airmass will work in here on Friday, but until then we will see
cloudy skies again tonight with a small chance for rain showers and
thunderstorms. Latest model guidance have drier solutions for tonight
compared to earlier runs as forcing and instability fields are rather
meager. Based on the data I lowered pops just a bit for tonight
having only the western third of the CWA with slight chance to chance
For tomorrow the clouds should slowly mix giving way to hopefully
more sunshine compared to today with temperatures in the middle 70s
along with light southeasterly winds. There is only a slight chance
for showers/thunderstorms for mainly the western zones closest to
the warm front. Tomorrow night should be dry leading into Friday.
On Friday the warm front rapidly lifts north in response to a
developing upper level trough. Once the front mixes north, very
warm and humid air returns to the region.
.LONG TERM...(Thursday Evening through Wednesday)
Issued at 310 PM CDT WED SEP 17 2014
A positively tilted trough will move through the Northern Plains and
Upper Midwest on Saturday, pushing a cold front into the area.
Models are a little slower with the front, so have delayed the start
of the precipitation in northwestern Missouri until during the
daytime period. Also, with the strongest dynamics associated with
the trough well north of the area, there will be little upper-level
support to aid the front. Surface and low level winds look to be
strongly veered as well and instability is modest at best. So the
potential for widespread rainfall loos to have diminished some,
especially the farther south one is away from the upper-level support
of the upper trough. So, have lowered PoPs for the day Saturday,
though much of the area remains with about 40 to 50 percent chance.
With veered winds and the upper trough moving away from its trailing
front, the front may be somewhat slow to clear the entire forecast
area, so there will remain a chance for showers and storms well into
the overnight hours. Overall, the threat of severe weather looks
rather low as instability is modest and shear is weak, in addition to
there being limited forcing.
Once that front does clear the area, high pressure will settle into
the region bringing cooler and drier weather to the region through
the early part of next week. By the middle of the week, as that high
shifts to the east, winds will become more southerly ahead of the
next upper trough. This may bring another chance for storms to
eastern Kansas and western Missouri by Wednesday of next week.
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1213 AM CDT THU SEP 18 2014
Light easterly winds advecting and expanding LIFR cigs westward over
all but northern MO but even those areas will see IFR/LIFR cigs.
IFR/MVFR fog also expected over the region which will lift by mid
morning. Some patchy locally dense fog should lift to LIFR/IFR
category once the stratus moves in. Next question is how soon will
the low clouds scatter out. Will continue previous thinking and
scatter out for afternoon.
Band of scattered elevated convection from northern KS into southwest
MO will persist for much of the night.