Area Forecast Discussion
Issued by NWS Springfield, MO

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FXUS63 KSGF 020503
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1203 AM CDT Thu Oct 2 2014

...06Z Aviation Update...

.UPDATE...
Issued at 1048 PM CDT WED OCT 1 2014

After a busy few hours earlier this evening, have had a chance to
make a few updates to the forecast for the overnight hours.
Convection continues to percolate late this evening across the
greater I-70 corridor, with very little activity making it far
enough south to affect the SGF CWA. As the low level jet continues
to strengthen over the next few hours, additional development is
expected, especially across the U.S. 54 corridor, where a Severe
Thunderstorm Watch is currently in effect. With a low
level boundary anchored across this area, really don`t expect to
see too much southward progress with elevated, LLJ- induced
activity for the remainder of the night, though we should still
see some increase in convection around sunrise tomorrow as the
main shortwave begins to approach (reference activity currently
across Oklahoma). This change has necessitated an adjustment to
QPF through 12Z, with a geographic shift north in the axis of
heaviest QPF, along with an overall downward adjustment in
magnitude. Some areas of central Missouri did see a good deal of
rain this evening (1.27" noted at Gravois Mills), and additional
heavy rainfall is still expected for tomorrow. As such, will
continue the Flash Flood Watch unchanged for now.

&&

.SHORT TERM...(This Evening through Thursday Night)
Issued at 250 PM CDT WED OCT 1 2014

Storms are developing across central Missouri just north of the
area and also across southeastern Kansas. This activity will
continue to drift to the northeast late this afternoon into early
this evening. Deep layer shear is greater than 40kt across
southeastern Kansas across western Missouri into central Missouri.
Gulf moisture is starting to increase across the region and is
increasing the instability. MLCape values of 1500 to 2000 J/kg
will be in place across these locations. Supercells will develop
and large hail and winds are expected with these storms. As the
low level jet increases low level shear will increase quickly this
evening with 0-1km bulk shear values over 25kt. This will support
a risk of tornadoes which will be best late this afternoon into
the evening hours.

Later this evening into the overnight hours a west to east
boundary will slowly sag south into the area. This will then
become the focus for storms develop and training along the
boundary from west to east. This will transition the risk from
this activity to more of a flooding risk especially with storms
training north of I-44 where 3 to 5 inches of rainfall will be
possible. We have therefore issued a Flash Flood Watch from this
evening through Thursday afternoon for locations generally along
and north of I-44.

A cold front and upper level trough will spread west across the
region Thursday into Thursday night. There will be ongoing
convection across the area Thursday morning from the storms that
develop this evening and tonight, mainly along and north of I44.
This activity is expected to decrease during the morning hours,
but there are questions if it will completely dissipate and if
additional convection will develop on outflow boundaries as a weak
cap will be in place across the area. So, storms could continue to
develop through the morning hours.

The front will push through the region Late Thursday morning into
Thursday evening from west to east. Storms will develop along the
front, and could be supercellular in nature as they initially
develop. As the front races east Thursday afternoon into Thursday
evening a line or broken line of storms are expected to develop.
The low level jet will decrease during the day and this will
decrease the low level shear across the area during much of the
day Thursday. Deep layer shear will support organized updrafts and
there will be a hail and wind risk with these storms. The weaker
low level shear will limit the overall tornado risk Thursday, but
will to see if enough instability and namely low level instability
can develop which will be dependent on how the convection behaves
Thursday morning and how quickly the atmosphere can recover.

.LONG TERM...(Friday through Wednesday)
Issued at 250 PM CDT WED OCT 1 2014

A cooler airmass will spread into the region Friday into the start
of the weekend behind the system that will affect the region this
evening into Thursday night. Highs will warm into the 60s both
Friday and Saturday afternoons highs in the 50s possible across
some locations across central Missouri Saturday afternoon. Lows
will drop into the upper 30s to lower 40s Saturday morning. Winds
will increase and be gusty Friday as a tighter pressure gradient
develops over the region. Winds will start to relax some Friday
night into Saturday, but do not think they will go clam and
will remain in the 5 to 10 mph range. Lows are expected to drop
into the 30s across potions of the region Friday night, but with
the winds expected to not go clam this may limit frost potential.
There could still be some patchy frost development in protected areas
and valleys Saturday morning but do not expect widespread develop
at this time.

A gradually warming trend will then occur Sunday into the middle
of next week as highs warm back into the 80s by next Wednesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1200 AM CDT THU OCT 2 2014

Convection should remain away from the terminals until closer to
daybreak, with storms then affecting JLN, before moving east with
time to impact SGF and BBG. Convection will initially be scattered
in nature during the morning and early afternoon hours, before
becoming better organized during the late afternoon and early
evening as a strong cold front approaches. A line of strong,
perhaps severe, thunderstorms will impact the region from west to
east tomorrow afternoon or evening, though exact timing remains
somewhat in question. IFR or lower is a good bet within stronger
storms tomorrow, along with gusty winds. Have indicated most
likely period for stronger storms with +TSRA mention, though
again, timing is subject to change.

That strong cold front will sweep across the region tomorrow
evening, with a sharp wind shift to the northwest as it passes.
MVFR cigs are then expected behind the front as much colder air
builds in.

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH through this evening FOR MOZ055>058-066>071-
     077>081-088-089.

KS...FLASH FLOOD WATCH through this evening FOR KSZ073-097-101.

&&

$$

UPDATE...Boxell
SHORT TERM...Cramer/Wise
LONG TERM...Wise
AVIATION...Boxell






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