Area forecast discussion
National Weather Service Springfield MO
651 am CDT sun may 19 2013
Short term...(today and tonight)
issued at 316 am CDT sun may 19 2013
Ongoing elevated and weakening convection and increasing confidence
in severe weather later today will be the focus for today and
tonight. Supercells and/or a squall line of thunderstorms capable
of producing very large hail...damaging winds...locally heavy
rainfall and tornadoes are all possible.
Residual convection that produced severe weather across the plains
made its way into portions of southeastern Kansas and the western
Missouri Ozarks early this morning. A few showers lingered and
struggled to continue in the face of a strong cap over the region.
Some light showers or an isolated storm may occur through
sunrise...but will continue to try and fight through the elevated
mixed layer in place over the area.
The atmosphere over the Ozarks will undergo significant
destabilization through the afternoon as the upper level trough
over the west moves into the plains and becomes negatively tilted
and an upper low develops over the northern plains. This will
allow a cold front to approach the region and aid in eroding the
strong cap over the region. Continuing southerly flow from the
Gulf will continue to feed moisture and instability into the
area through the day. Cape values around 3000 j/kg will be in
place across the region by this afternoon. The increasingly strong
low level jet will nose in the region as the exit region of an
upper level jet steak moves over the region late this afternoon
into the evening hours. This will work to destabilize the airmass
over the Ozarks quickly with thunderstorm development expected
to occur across eastern Kansas...northeastern Oklahoma by this
afternoon. These storms are expected to be supercellular initially
as 0-6km bulk shear in excess of 40kt and backing winds in advance
of the cold front support rotating storms. As the storms move east
off the front...cold pool conglomeration should result in a
developing strong squall line that makes its way into the
Missouri Ozarks. The storms may remain supercells as far east as
the Interstate 49 corridor before transitioning...however there
may be residual supercellular characteristics to a few embedded
storms as the system moves east across the Ozarks.
The wind profile...shear and instability expected would support
very large hail...damaging winds and tornadoes with any
supercells. If storms do indeed go linear...there would be an
enhanced threat for widespread damaging winds. Low level shear
would also support mesovortex potential.
The timing of the storms remain similar to the previous forecast
with most of the activity impacting locations west of I-49 from
5-9 PM today and west of Highway 65 by midnight.
Long term...(monday through saturday)
issued at 316 am CDT sun may 19 2013
Lingering severe thunderstorms Monday morning and the potential
for a second round of severe weather capable of producing very
large hail...damaging winds...flooding and tornadoes remains the
focus for the start of the week.
The upper level low will linger over the northern plains into
Monday as another surface low develops across western Kansas into
northern Texas and another short wave and associated jet streak
round the base of the trough associated with the upper low. This
will bring another round of severe weather to the region Monday
evening into Tuesday morning. The orientation depicted by the
models continues to line up along the the cold frontal boundary as
it moves through the region. The airmass in advance of the front
will remain moist and unstable as continuing southerly flow feeds
the warm sector ahead of the front. Precipitable water values from
1.5 to 2 inches are indicated by forecast soundings and the short
range models. Cape values will again be around the 2000 j/kg mark.
This combined with continuing low level jet interaction and the
jet streak previously noted will allow for the potential for
another round of severe storms. Large hail...damaging winds and
tornadoes will again be possible along with heavy rainfall leading
to flooding...in response to the amount of moisture that will be
available.
This system continues to suggest a slower movement to the east and
may linger across the eastern portions of the Ozarks into Tuesday.
The system will have moved east of the area by Wednesday as an
amplifying ridge moves into the plains. The models do indicate
several shortwaves that make their way across the ridge and bring
some slight chances for showers and storms through the rest of the
week.
&&
Aviation...(for the 12z tafs through 12z Monday morning)
issued at 640 am CDT sun may 19 2013
Significant low level moisture across the region this morning was
producing MVFR visibilities for area terminals this morning. Low
level wind shear associated with a strong low level jet over the
region will continue through 15z. A period of improving flight
conditions from middle morning through late this afternoon will bring
VFR flight conditions to the region. An approaching storms system
later today will cause weather are area terminals to deteriorate in
the vicinity of thunderstorms. The timing of the storms will need
to be monitored and updates to the going forecast will be made once
storms develop and move towards local terminals. An additional
period of low level wind shear will develop again over night
tonight into Tuesday morning in response to strong low level winds.
&&
Sgf watches/warnings/advisories...
MO...none.
Kansas...none.
&&
$$
Short term...Hatch
long term...Hatch
aviation...Hatch
