Area Forecast Discussion
Issued by NWS Springfield, MO

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000
FXUS63 KSGF 241700
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1200 PM CDT Thu Apr 24 2014

...Update for Aviation...

.MESOSCALE DISCUSSION...
Issued at 1000 AM CDT THU APR 24 2014

Forecast appears to generally be on track this morning, as an initial area
of elevated thunderstorms progresses east across the Ozarks.  While
this activity has shown brief periods of strengthening, it has
struggled to become particularly strong.  Suspect that convection is
fighting some dry air in the mid levels, per the 12Z SGF RAOB, and a
dwindling of forcing as the LLJ weakens/veers is not helping
either.  As such, while a quarter size hail report isn`t entirely
out of the question at some point this morning, the severe weather
threat with this morning convection will probably remain fairly low.

More organized convection is still expected to develop along/just
ahead of the frontal boundary as it begins to move into eastern
Kansas around 18Z or so, with that convection then progressing east
across the entire forecast area this afternoon.  With modest
instability and very steep lapse rates in place aloft, it does
appear that a few severe storms will be possible, with large hail
the primary threat.  Some severe wind gusts will also be possible,
especially with organized line segments, but mediocre low level
theta-e differentials will likely make it difficult to get
widespread damaging winds.

&&

.SYNOPSIS...
Issued at 252 AM CDT THU APR 24 2014

An unsettled pattern will bring several chances of showers and
thunderstorms, some severe weather and heavy rain to the area
throughout much of the forecast period.

Currently, showers and thunderstorms were occurring along a
frontal boundary from central Kansas into northeast Kansas and in
the vicinity of a low level jet over eastern Oklahoma into eastern
Kansas. The precipitation over eastern Kansas was entering a much
drier air mass and having trouble holding together as much more
than sprinkles. This is expected to change closer to sunrise as an
upper level trough and surface cold front shift east across Kansas
during the remainder of the night.

&&

.SHORT TERM...(Today and Tonight)
Issued at 252 AM CDT THU APR 24 2014

The front should be on the western doorstep of our forecast area
by 12-13z with the shortwave trough pushing into western Kansas.
Precipitation should begin to fall across our western CWA during
the morning hours and into the western half of the CWA by 18z.
With the slower onset of precipitation from previous models runs,
there is more opportunity for some higher instability to creep up
into the southeastern sections of the forecast area this afternoon
ahead of the front. A speed max will be rounding the base of the
mid/upper level trough which will push into the area this
afternoon. Deep layer shear of 30-50kts will be possible over
south central MO this afternoon. So the risk of some organized
severe storms has increased for the afternoon hours over our
southeastern CWA. There will be an initial shot of some
supercellular storms before the activity lines out, most likely
east of our CWA this evening. Therefore, we can`t rule out all
modes of severe weather roughly east of a Branson to Rolla line.
All of the precipitation should exit the CWA during the early
evening, with clearing from west to east. While a "cooler" air
mass will move into the area behind the front, lows should still
be in the mid to upper 40s tonight.

.LONG TERM...(Friday through Wednesday)
Issued at 252 AM CDT THU APR 24 2014

Friday should remain dry across the area and even with the front
to our south, the drier air in place with upper level ridging
should allow temperatures to climb back into the mid 70s to around
80. The front should start to lift back north Friday night and
into the area on Saturday. There will be a chance of showers and
thunderstorms along the warm front, but a strong elevated mixed
layer will develop behind the front during the day Saturday which
should limit convective development without any other triggering
mechanisms. Nocturnal thunderstorms will likely develop north of
the area, along and north of the warm front Saturday night as a
strong low level jet develops in advance of the next strong low
pressure system developing in the high plains. The severe storms
on Saturday into Saturday night should remain west of the CWA.

Things become more interesting heading into Sunday and Monday as
the upper level low slowly tracks to the east. Strong to severe
storms will likely develop along a dry line with strong jet
interaction and deep shear to our west and then shift east into
the area later in the day/night. Additional strong to severe
storms will be possible on Monday depending on how far east the
moisture axis shifts Sunday night. Models have some differing
solutions here with the ECMWF slower to shift the moisture axis
eastward and thus a better chance of strong to severe storms
redeveloping over the eastern CWA on Monday.

With a blocking pattern in place over north America, the low will
be slow to leave the area and will likely be cycling energy over
the area through at least the middle of the upcoming week. Colder
air will eventually be drawn south into the area on Tuesday night
with models showing 0 to -2 850 mb air by 12z Wed. Model surface
temperatures are still in the low to mid 40s so will keep
precipitation chances as all rain for now. Slightly colder air is
expected on Wednesday night with 850 mb air of -1 to -3.  Will
still keep snow/rain mix out of the forecast for now but this will
need to be monitored. We currently will go with lows in the upper
30s to low 40s both Tuesday night/Wednesday night so probably not
a frost situation, but this will also need to be monitored as we
get closer.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1157 AM CDT THU APR 24 2014

Breezy south winds will continue early this afternoon ahead of a
cold front. That front, and an associated line of thunderstorms,
will sweep across the region this afternoon, likely affecting all
three terminal sites. Clearing skies and west to northwest winds
are expected behind the front tonight.

&&

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

$$

MESOSCALE...Boxell
SYNOPSIS...Lindenberg
SHORT TERM...Lindenberg
LONG TERM...Lindenberg
AVIATION...Boxell






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