Area Forecast Discussion
Issued by NWS Springfield, MO

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FXUS63 KSGF 221146

646 AM CDT Wed Apr 22 2015

...12Z Aviation Update...

.SHORT TERM...(Today and Tonight)
Issued at 324 AM CDT WED APR 22 2015

As of 3 AM, a surface cold front was in the process of moving
south across southern Missouri. Yet another round of showers and
thunderstorms has been forced up along and immediately behind the
front. This activity is expected to largely push out of southern
Missouri and/or dissipate by sunrise.

That surface front will continue to progress south today into the
Red River region before stalling. However, a 850 mb front will
settle south and then stall from eastern Kansas into northeast
Oklahoma and then down towards Little Rock by late this afternoon.
This front will then remain stationary this evening before nudging
a bit northeast overnight tonight.

The presence of this elevated front will keep at least a marginal
threat for showers and thunderstorms going today across portions
of extreme southeastern Kansas and far southwest Missouri.
Prospects may then increase later tonight as 850 mb flow firms up
out of the south and induces weak isentropic upglide. Again, this
would be primarily across extreme southeastern Kansas and southern

Temperatures will be below normal today as cool air advection
will be in place. Cloud cover will also come into play over
mainly southern Missouri. Highs across most areas will be in the
lower 60s. Areas across central Missouri may not get out of the
upper 50s.

Of more concern is temperatures for tonight...especially across
central Missouri. A surface ridge axis will cut southeast across
the region resulting in light winds. Meanwhile, model cross-
sections indicate that mid and high level clouds may remain just
south of the area for most of tonight. This would result in
overnight lows dropping down into the middle and upper 30s with
frost potential. After collaboration with offices to our north and
east, we have decided to hold off on a Frost Advisory to give the
day shift a chance to assess cloud potential. For now, we will hit
the frost concern in the Hazardous Weather Outlook.

.LONG TERM...(Thursday through Tuesday)
Issued at 324 AM CDT WED APR 22 2015

Upper level height rises will then overspread the area from
Thursday into Thursday evening as strong upper level energy digs
and then pivots east across the northern Baja of California. While
a shower or thunderstorm will remain possible across southwestern
Missouri, most (if not all) of the area should be largely dry on
Thursday and Thursday evening.

That upper level energy will then eject towards our region later
Thursday night with isentropic upglide overspreading a returning
warm front. Showers and thunderstorms will become increasingly
likely from later Thursday night into Friday morning.

Convective coverage and intensity then becomes a tougher call as
we get into Friday afternoon and Friday night. Models deepen an
area of surface low pressure across southeastern Colorado Friday
afternoon and then eject the low into eastern Kansas or western
Missouri by 12 UTC on Saturday. Indications are that surface based
convection may develop along or west of the I-35 corridor in
Kansas late Friday afternoon. Initiation is a bit more in question
farther south into Oklahoma along what will be a sharpening dry
line as a strong capping inversion will likely be in place.
Convective initiation potential may then increase in the evening
as a low level jet impinges on that warm front from eastern Kansas
into western Missouri.

Deep layer and low level shear will certainly be supportive of
severe storms. The bigger question will be the capping inversion
and instability. The better prospects for severe storms (across
the Ozarks) may actually come Friday night closer to that warm
front. Convective mode is a tough call as either supercells or
line segments would be possible. Farther south into the warm
sector, that capping inversion (likely due in part to an elevated
mixed layer) may continue to hold down convection for much of the
night. It goes without saying that the position of that warm front
(and the surface low track) will be key for severe potential
across the Missouri Ozarks. It could set up closer to I-70 or
farther south closer to Highway 60.

That surface low will then move through the Ozarks on Saturday
with a few leftover showers and perhaps a thunderstorm. Sunday
then looks dry before the next storm system takes aim on the
region for early next week. Global models are all over the place
with the timing and especially the track of the next system. The
00Z ECMWF largely keeps upper level digging energy and most
precipitation south of the Ozarks. In stark contrast, the 00Z GFS
tracks a strong closed low right over the Missouri Ozarks.
However, the GFS ensemble members are largely all over the place.
The 00Z Canadian model is more in line with the ECMWF. We have
sided closer to the ECMWF/Canadian model for now and kept PoPs
generally in the 20-40% range early next week.

After a warming trend late this week (ahead of that first storm
system), temperatures will return to below normal values by
early next week.


.AVIATION...(For the 12Z TAFS through 12Z Thursday Morning)
Issued at 637 AM CDT WED APR 22 2015

A frontal boundary moved through the region overnight, resulting
in north to northeast winds across the area. Winds will remain
northerly, and generally light through tonight.

Sky conditions are generally expected to remain VFR through the
period, though a few hours of occasional IFR will be possible this
morning at BBG. Right now, it appears that precipitation will
remain south of the terminals tonight, though it`s not beyond the
realm of possibility that a shower/thunderstorm could eventually
impact BBG.




SHORT TERM...Schaumann
LONG TERM...Schaumann
AVIATION...Boxell is the U.S. government's official web portal to all federal, state and local government web resources and services.