Area Forecast Discussion
Issued by NWS Springfield, MO

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252
FXUS63 KSGF 250837
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
337 AM CDT Tue Apr 25 2017

.SHORT TERM...(Today and tonight)
Issued at 239 AM CDT Tue Apr 25 2017

Low level pressure gradients will tighten today ahead of low
pressure developing across northwestern Oklahoma. Brisk and gusty
south winds will be the result with gusts in the 30 to 40 mph
range from mid-morning onward. Despite increasing high clouds,
high temperatures today will warm into the upper 70s and lower
80s.

Meanwhile, upper level low pressure will slowly move east today
across Wyoming with multiple short wave troughs traversing
northeast to the south of this low across the southern and central
Plains. As this happens, that surface low pressure will slowly
move east with a cold front extending from far northwestern
Missouri, southwest into eastern Kansas and north-central Oklahoma
by late afternoon.

Convective initiation should be held at bay through mid-afternoon
due to the presence of an elevated mixed layer (EML) which will
effectively "cap off" thunderstorm development. Upper level
height falls will then overspread eastern Kansas late this
afternoon. These height falls in combination with low level
convergence along the front should result in convective initiation
across eastern Kansas and northeastern Oklahoma somewhere in the
5 to 9 PM time frame.

These storms should then expand in coverage with a broken line of
storms or line segments likely being the main convective mode
across southeastern Kansas and western Missouri from mid-evening
through the overnight period. Damaging wind gusts over 60 mph and
hail up to the size of half dollars will be possible with the
strongest updrafts.

Due to the expected presence of multiple waves (weak surface lows)
along the front, we remain unclear on how quickly the actual cold
front will move east overnight. It is quite possible that we see
multiple little clusters of storms form and move northeast across
western Missouri and southeastern Kansas. We will therefore have
to watch the hydro situation. In contrast, areas of the eastern
Missouri Ozarks may remain dry tonight.

.LONG TERM...(Wednesday through Monday)
Issued at 239 AM CDT Tue Apr 25 2017

That front will slowly move east across the Ozarks on Wednesday.
Models have actually slowed this feature down. This does open the
door for a greater potential for severe storms on Wednesday over a
larger portion of the Missouri Ozarks. A big key will be whether
or not overnight storms can develop enough of a cold pool to
become the effective front. If this happens, the main severe
weather threat would be shunted east of the area.

If storms are not widespread enough overnight, the front itself
will be the main forcing mechanism for storms on Wednesday.
Moderate instability and decent wind fields would support an
increasing severe risk from Wednesday afternoon into Wednesday
evening, especially across south-central Missouri and the eastern
Missouri Ozarks. These types of setups can be conducive to line
segments producing wind damage and mesovortices (for line segments
which bow northeast). Once again, we will also have to watch the
hydro situation.

Most of Thursday should then be dry before a very active and
troublesome pattern begins to set up for the end of the week.
Initially, global models bring short wave energy and a relatively
weak storm system through the region from Thursday night into
Friday. Showers and perhaps a few thunderstorms will be possible
during this time frame.

The upper level flow will then turn southwesterly from Friday
night into Saturday as a strong upper level jet stream digs
towards the Four Corners region and deepens a trough over the
western United States. As this happens, a baroclinic zone will
develop and strengthen from the southern Plains into the Mid-
Mississippi Valley region. Multiple rounds of showers and
thunderstorms are expected near this zone from Friday night into
at least early Sunday morning.

While model QPF can be misleading for a number of reasons
(especially out that far in the forecast period), there is
currently a pretty strong consensus for a 3-6" axis along and just
north of wherever that baroclinic zone sets up. This heavy
rainfall setup also has strong backing from the St. Louis
University CIPS Analog Guidance. Needless to say, QPF of this
magnitude would result in a widespread flooding risk.

Depending on the eventual track of this storm system, there may
also be severe weather to contend with from Friday into the
weekend. Those with outdoor plans for the upcoming weekend should
keep close tabs on the forecast as there is the potential for
multiple weather hazards.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1152 PM CDT Mon Apr 24 2017

KSGF/KJLN/KBBG tafs: VFR flight conditions are expected throughout
the TAF period, with an increase in mid to high level clouds. The
pressure gradient ahead of the next storm system will produce
southerly winds of 15 to 25 knots at the TAF sites, mainly between
14Z Tuesday and 00Z Wednesday. There could be some gusts as high as
30 knots at KJLN.

Convection will begin to form late Tuesday afternoon and evening
across Kansas and Oklahoma. These storms will them track eastward
and may affect the KJLN terminal between 04Z-06Z, but should
remain west of KSGF and KBBG. Will include a VCTS at KJLN for this
time frame.

&&

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

$$

SHORT TERM...Schaumann
LONG TERM...Schaumann
AVIATION...Raberding



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