Area Forecast Discussion
Issued by NWS Springfield, MO

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000
FXUS63 KSGF 171712
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1212 PM CDT Wed Sep 17 2014

...18Z Aviation Update...

.UPDATE...
Issued at 1106 AM CDT WED SEP 17 2014

Several areas/clusters of elevated thunderstorms continue to develop
and drop southeast across the central portions of the forecast area
late this morning.  While not quite as organized or widespread as
the early morning storms, torrential rainfall and frequent lightning will
remain likely with the heaviest activity.

Low level jet induced lift should weaken through 1 PM, with a
corresponding downward trend in convective strength and coverage
expected with time. With a warm front still in the area and
several ripples in the flow aloft making their way through,
scattered thunderstorms will remain possible through the afternoon
hours today across the region. Frequent lightning, heavy rain, and
some small hail will be possible. Given this morning`s heavy rain,
a limited to elevated flood threat will continue, especially if
additional storms move over the same areas that saw the heaviest
rain this morning.

Temperatures will also remain tricky this afternoon given such a
sharp gradient with the rainfall and associated cloud cover.  Areas
west of Springfield should warm into the mid 80s without much
trouble.  Areas east will remain in the 60s and low 70s given
rainfall and abundant cloud cover.  Confidence in temperatures is
lowest for the Springfield area and U.S. 65 corridor, where the
gradient will be sharpest. For now haven`t made any major changes to
temperatures, other than to sharpen the gradient across the central
portions of the CWA.

&&

.SHORT TERM...(Today and Tonight)
Issued at 226 AM CDT WED SEP 17 2014

Cu/accas cloud field and area of showers/thunderstorms starting to
develop between 200-230 am over east central KS into central MO in
response to increased lift/isentropic ascent from approaching
disturbance. Vertical shear, elevated instability, general
moisture advection will continue and expected an increase in
precip coverage in the near term. Best mucape values of 1000-1500
J/kg reside over the western cwfa and will support some marginally
severe hail in isolated stronger updrafts into the early daylight
hours.

Convection will weaken late this morning as the low level/850mb flow
veers/weakens. Convection in some form may last into the afternoon.
Expect to see some redevelopment late today and/or tonight as the
same general elevated convection scenario replays itself fairly
close to the same general area it is developing now.

Fog: Some areas of dense fog are noted over southern MO, mostly
due to stratus build down, and expect some areas of dense fog to
occur before widespread showers move in. The focus will likely be
in areas along and south of the higher terrain along and south of
MO Highway 60.

.LONG TERM...(Thursday through Tuesday)
Issued at 226 AM CDT WED SEP 17 2014

Ongoing elevated showers/thunderstorms will likely be occurring to
start the period Thursday. Rising mid level heights with an
approaching ridge should suppress more widespread convection late on
Thursday and Thursday night. Dry and warm weather is expected
Friday.

Timing is the main concern for rain/tstm chances over the upcoming
weekend. Remnant weakening upper level shortwave from a tropical
system is still expected to move ene into the central/southern
Plains and phase with an approaching mid latitude shortwave by
Saturday.

00Z guidance: ECMWF looks slower versus the GEM and GFS
by about 12 hours. If the ECMWF verifies, the better chances for
precip will hold off until later Saturday night-Sunday-Sunday
night. GEM/GFS point more toward Sat afternoon/Saturday night. GFS
ensemble looks a tad slower than operational GFS, but for now went
with the cr blend, modifying onset time a bit later (Sat
afternoon).

Progressive nature of the weekend shortwave will kick out the
precip fairly quickly (no matter what the timing). Dry weather is
then expected Monday-Tuesday as Canadian high pressure moves into
the Midwest/Corn belt.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1209 PM CDT WED SEP 17 2014

Thunderstorms will again affect the SGF terminal early this
afternoon. Additional storms will be possible at both SGF and BBG
later this afternoon into this evening. A few showers can be
expected at JLN as well, though most activity should stay to their
east. Periods of IFR vis and cigs can be expected with any
thunderstorms.

Showers/storms should give way to IFR to LIFR fog and low stratus
tonight through mid morning tomorrow at SGF and BBG. Vis and cigs
approaching airport mins will be possible, especially at BBG.

&&

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

$$

UPDATE...Boxell
SHORT TERM...DSA
LONG TERM...DSA
AVIATION...Boxell






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