Area Forecast Discussion
Issued by NWS Springfield, MO

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642
FXUS63 KSGF 212322
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
622 PM CDT SAT MAY 21 2016

...AVIATION UPDATE...

.SHORT TERM...(This evening through Sunday)
Issued at 240 PM CDT Sat May 21 2016

The upper level ridge across eastern Kansas and western Missouri
along with surface high pressure are making for a very nice day
across the Ozarks. This combination will continue through this
evening and Sunday as the upper ridge slowly shifts east over the
region. A weak upper level short wave may bring a shower or
isolated thunderstorm to areas from Fort Scott, KS to Nevada and
north late this evening into the overnight hours, but chances are
very low.

Temperatures today under the mostly sunny skies will reach the
middle 70s for much of the area and the upper 70s to around 80 for
Sunday. Southerly winds will begin to increase slightly during the
day Sunday as a storm system over the Plains produces a slowly
increasing surface pressure gradient as the surface high shifts
east. Otherwise Sunday should be another great day.

.LONG TERM...(Sunday Night through Saturday)
Issued at 240 PM CDT Sat May 21 2016

The overall upper level pattern will be slow to advance Sunday
night and Monday, with an omega block remaining in place across
much of North America to start the workweek. Some elevated
convection will be possible Sunday night and again Monday night,
as the LLJ overspreads the edge of the EML across areas just to
our west Sunday night, and over the western portions of the
forecast area Monday night. A few strong storms will be possible,
with large hail being the main threat given the elevated nature to
the convection.

By Tuesday, better moisture will start to build into the area,
with dewpoints increasing into the upper 60s and low 70s. Aloft,
very steep mid level lapse rates will build into the area,
resulting in a very unstable airmass. However, the EML that is
resulting in the steep lapse rates will also result in a strong
capping inversion over the area, raising questions about just
when/where convection will be able to form through at least mid
week.

The synoptic scale boundaries will remain well to our west through
at least Wednesday, with a stationary front likely remaining west
of Wichita, and a dryline stretching south across central and
western Oklahoma. For our forecast area, I suspect the bulk of
what we see through mid week will be the result of some
combination of: 1. convection from the Southern/Central Plains
moving far enough east to affect the forecast area, 2. nocturnal
convection forced by the LLJ, or 3. convection that forms on
outflow from option 1 or 2. Needless to say, confidence in exact
timing and coverage is low.

That said, anything that does affect the area through mid week
will have the potential to be severe, given moderate shear and
high to very high instability. Very large hail looks to be the
most likely and widespread threat, though high winds and/or a few
tornadoes will also be possible. Flooding could also become a
concern, though recent model runs are suggestive of a more
scattered nature to the convection. This will point toward more of
a localized threat, dependent on the exact track of individual
thunderstorms.

While significant run to run and model to model differences remain
in timing, a more robust shortwave should eventually eject east
across the Southern Plains during the latter portion of the
workweek or going into the Memorial Day weekend. Assuming a
favorable track, this shortwave would LCL result in the most
widespread severe weather threat for the area, as it will bring
with it enough lift/mid level cooling to overcome the capping
inversion, as well as increased shear. The nature of the overall
upper level pattern, with a closed low over the western US, makes
timing of this feature especially problematic, but this will
certainly be something to keep a close watch on over the next 5-7
days.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)

Pilots flying in and out of the southwest Missouri airports can
expect VFR conditions over the next 24 hours.

We could experience some mid level clouds later tonight, however,
no low ceilings are expected.

Look for northeast breezes to eventually shift to the southeast by
Sunday morning.

No obstructions to visibilities are anticipated at this time.

Safe Travels.

&&

.SGF Watches/Warnings/Advisories...
MO...NONE.
KS...NONE.
&&

$$

SHORT TERM...Hatch
LONG TERM...Boxell
AVIATION...Cramer



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