Area Forecast Discussion
Issued by NWS Springfield, MO

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000
FXUS63 KSGF 241121
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
621 AM CDT Tue Mar 24 2015

...12z Aviation Forecast Update...

.SHORT TERM...(Today and Tonight)
Issued at 332 AM CDT TUE MAR 24 2015

A warm front is making its way north into the region early this
morning. Over the past few hours, this low level boundary has
become the focus for scattered shower and thunderstorm
development. This activity developed in south central Kansas late
last evening and has gradually spread east into portions of
extreme southeastern Kansas and western Missouri. A solid low
level jet will continue to impinge on this front, and with modest
CAPE aloft, this scattered shower and thunderstorm activity will
persist into the daylight hours of this morning.

Rain chances will tend to shunt northward with time during the
mid/late morning hours as the warm front gets a synoptic "boost"
to the north by the strong low level jet. In fact, there will
likely be a lull in rainfall from around midday toward the middle
afternoon hours as the low level jet delivers a rather stout cap,
with CIN levels increasing to 300 J/kg. This lull, however, will
be short lived as a progressive, strong shortwave moves into the
Midwest and takes on a negative tilt. A dryline/prefrontal trough
will shift toward the MO/KS state line by the middle of this
afternoon and become the focus for scattered thunderstorm
development.

While there is plenty of large scale support for thunderstorm
initiation, there are a few negatives worth noting. Surface
dewpoints seems a bit overdone with the short range models. It
will be tough to see 60+ dewpoints this far north. Mid/upper 50s
appear much more plausible given upstream observations. The low
level jet will be overhead about the time of thunderstorm
initiation, however this feature will quickly shift east of the
area. Finally, the upper level jet positioning/structure is not
ideal.

Regardless, strong mid level height falls and convergence along
the surface boundary should be enough to overcome the cap and
initiate scattered storms in the vicinity of the MO/KS state line
during the late afternoon hours. Deep layer shear supports
supercellular structures and shear orientation to the low level
boundary support discrete cells for most of this event for our
area. Given steep lapse rates aloft, the primary hazard will be
the potential for large hail. Dewpoints in the 50s will likely
result in relatively high cloud bases. In addition, low level
shear will be decreasing with time as the low level jet quickly
exits to the east. These two factors will limit tornado potential.
Localized downburst winds are plausible.

Once these storms erupt, they will not hesitate to move east. In
fact, the window of opportunity for storms across the area is in
the 4-6 hour range, focusing from late this afternoon through
early this evening. Storms will race east and exit most (if not
all) of the area by midnight.

.LONG TERM...(Wednesday through Monday)
Issued at 332 AM CDT TUE MAR 24 2015

Another round of active weather will develop across the region
Wednesday afternoon and persist across the area Wednesday night
into Thursday morning. The 00z guidance has offered some minor
changes to the going forecast. The most pertinent being that the
synoptic front is a little further south than previously forecast.
This is a trend worth watching as it may shunt the better chances
for severe storms further south. For now, there is still a risk of
severe for areas southeast of the I-44 corridor, with hail and
wind the primary risks. As mentioned in previous forecasts, the
potential for a few hydro issues is increasing. Better quality
moisture will be available this with system and a widespread 1-2"
rainfall is possible across the southeast half of the area. With
portions of southern and south central Missouri still rather moist
from previous rains, will need to watch for flooding.

The pattern from Thursday into early next week take a turn for the
cold. Below average temperatures are expected much of the period.
Northwest flow aloft will keep a near constant feed of cold fronts
and brief chances for precipitation from time to time. Cannot rule
out a light rain/light snow mix Thursday night and again Friday
night. Something to keep an eye on given recent warmth and budding
vegetation.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 608 AM CDT TUE MAR 24 2015

Mainly VFR conditions will prevail for pilots flying in and out of
the area through the next 24 hours. There are a few aviation
concerns to be aware of today for pilots flying. There will be a few
thunderstorms early this morning and some low level wind shear
through about 15z. Gusty south winds will develop by midday and
early afternoon with gusts approaching 25 knots for JLN and SGF.

Another round of convection is expected to develop late this
afternoon and early evening. Have a prob30 group for convection
between 21z to 24z followed by a tempo group early in the evening
from 00z to about 03z. Skies and convection will clear out by late
evening and winds will relax as well as shift to more westerly.
TSRA may drop the visibility down to around 5sm possible this
evening.

&&

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

$$

SHORT TERM...Gagan
LONG TERM...Gagan
AVIATION...Griffin





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