000
FXUS63 KSGF 132343 AAA
AFDSGF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPRINGFIELD MO
643 PM CDT Sun Jul 13 2014

...Updated Aviation Section...

.UPDATE...
Issued at 643 PM CDT SUN JUL 13 2014

Rather pesky forecast for this evening into the overnight hours.
To this point, the atmosphere has been very slow to respond to
modest, though increasing height falls aloft. A surface boundary
(mainly just a wind shift) is approaching the plateau and will
continue a slow, steady southward progression with time. Behind
this wind shift, scattered convection has developed, but it is
struggling. Dry air in the mid levels along with meager lapse
rates are negative factors thus far. Just to the north of the
outlook area, convection has been firing along the 850mb front,
however this feature has barely been moving. As a result, showers
and storms have been flirting with entering our central Missouri
counties for much of the day.

Looking at the near term, convection allowing models, they are
overdoing the amount of convection. This is likely due to ample
CAPE availability. Nevertheless, the atmosphere is dictating that
this amount of CAPE simply just isn`t enough to support more than
low end scattered development.

With time this evening, the 850mb front will move southward. This
will likely be the feature to key in on with PoPs going forward,
and it appears that the current forecast is too fast with
spreading the better rain chances to the south. As a result, will
tweak the forecast once the latest near term model runs are in and
the 00z raob is available. In all likelihood, will need to drop
PoPs in the west and southwest and focus the better rain chance
across central MO and the eastern Ozarks.

&&

.SHORT TERM...(This Evening through Monday)
Issued at 310 PM CDT SUN JUL 13 2014

A weak cold front is currently pushing south into the far northern
portions of the forecast area this afternoon. Ahead of this front
a dry airmass in place in the middle levels and low level wind
shear vectors are parallel to the front. The front is bringing an
increase in mid level moisture with it. Scattered storms are
beginning to develop along the front just north of the area
currently during the mid afternoon hours. This trend will continue
through this evening as scattered storms develop and move east
behind the front as the front moves south and the mean level storm
flow is to the east.

The post frontal nature of the storms will be elevated. Further weak
Theta-E differences will limit the overall wind potential as well. Deep
layer shear will increase some from north to south this evening.
Instability will be tall and skinny and not overly strong...but
with the increasing shear a few strong storms capable of producing hail
up to the size of nickels. The strong to marginally severe risk
will overall be isolated in nature across the area with the better
chances east of the area across eastern Missouri.

Coverage in storms will decrease from north to south overnight as
the front sags south. A few lingering showers may be possible across far
south central Missouri early Monday morning before the activity
moves south into Arkansas.

Temperatures behind this front will only be slightly cooler as highs
top out in the middle 80s to lower 90s before a stronger cold
front spreads southeast through the region Monday afternoon.

Storms are once again expected to develop along this front. Deep
layer shear will be slightly stronger along with better Theta-E
differences than today. Still do not expect widespread severe
weather but a few of the stronger storms will be capable of hail
up to quarters and winds up to 60mph. Best potential for stronger
storms will be across south central Missouri where the best
instability will be located.

.LONG TERM...(Monday Night through Sunday)
Issued at 310 PM  CDT SUN JUL 13 2014

A much cooler airmass will spread into the region behind the cold
front Monday night through much of the week...with a warming
trend returning late in the week into next weekend. Highs on
Tuesday through Thursday are expected to only warm into the middle
to upper 70s...which is well below normal for mid July and will
be very close to the overnight low temperatures experienced the
last few nights. Lows will drop into the 50s each night. The
coolest night will be Tuesday night into Wednesday morning when
lows in the lower 50s are possible as the surface high will be
over the area.

A piece of upper level energy will move south through the plains
then east across Arkansas Tuesday into Thursday. A few showers
may be possible across far southern Missouri Tuesday and Wednesday
as this occurs. A front will then lift back north on Friday and
may bring the potential for a few thunderstorms late in the week.

Highs in the middle 80s to near 90 will return by next Sunday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 643 PM CDT SUN JUL 13 2014

Complex, slow developing near term weather situation across the
area this evening. See the update section above for greatest
detail. The end result on the TAFs was to remove a few TEMPO
groups at JLN/SGF and focus the better chances for a few showers
and storms to the late evening. Rain chances have been removed at
BBG given the current setup and near term model solutions. A wind
shift line will spread slowly south through the area this evening,
resulting in a brief shift to northerly flow, but quickly becoming
light and variable. The more substantial cold front will plow
through the region Monday afternoon. This will bring a small
window of opportunity for showers and storms (a few could be
strong/severe). Northerly winds behind the front will strengthen
during the late afternoon and in the hours just beyond the TAF.

&&

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

$$

UPDATE...Gagan
SHORT TERM...Wise
LONG TERM...Wise
AVIATION...Gagan