Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KEAX 241128
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
628 AM CDT TUE MAY 24 2016

.Discussion...
Issued at 341 AM CDT TUE MAY 24 2016

For this morning, will be watching two features for precipitation
chances across the forecast area: 1) ongoing convection that has
been dropping southeast across eastern NE and now southwest IA since
last evening; and 2) robust, slow-moving convection just north of I-
70 in Kansas. Some sort of gravity-wave feature is evident on KTWX
and is moving northeast toward the forecast area, possibly combining
with eastward-translating isentropic lift to encourage the showers
and storms in Topeka`s CWA to begin moving and developing more east-
ward this morning. This feature may also reach the convection in
northwest MO/southwest IA and support some upscale growth there,
allowing storms to expand and strengthen, potentially enough to
throw out an outflow boundary of their own and support more south-
eastward development across the forecast area. As a result, will be
watching mainly northwest MO and far eastern KS/western MO for
increasing thunderstorm chances this morning into the early
afternoon as both these features, and isentropic support, move
closer. Deep layer shear is a bit weak for widespread severe weather
concerns this morning through early afternoon, but at least 500 to
possibly 1500 J/kg of elevated instability may be available for
storms to work with across the forecast area, possibly supporting a
few strong updrafts and perhaps some small hail.

Confidence decreases in overall precipitation evolution this
afternoon when isentropic support begins to wane, especially since
any other support for convective initiation will be nebulous and
will strongly depend on the presence and location of any outflow
boundaries left by morning convection. Capping should be fairly
insignificant again today, so any small-scale convergent zones may
be enough to support convective initiation CWA-wide -- especially as
moisture and thus instability continues to build this afternoon. As
a result, was not comfortable going much below 30 PoPs in any period
or location today.

Convection will once again develop in the central to High Plains
this afternoon or evening and should propagate eastward, and will be
supported by a developing low-level jet as lee-side low pressure
begins to deepen at low levels late this evening and tonight. Most
high-res models indicate the presence of an eastward propagating MCS
late tonight, but could not be more different in its location --some
take it across southern KS and into southwest MO, and some show an
MCS-like feature traveling across NE and IA, then dropping into
eastern MO. Tried not to get too cute with PoPs for tonight because
of the breadth of these solutions, but they may need significant
updating today if models continue to show the more southern feature
possibly brushing the southwest corner of the forecast area tonight.

The thermal ridge will edge eastward in response to the northeast-
ward ejection of surface low pressure out into the Plains on
Wednesday, shifting the elevated mixed layer eastward and likely
holding down convective potential in most locations Wednesday.
Models have been persistent in developing an insurmountable cap
ahead of the dryline in KS and OK; thus, our precipitation chances
are also lower without anything to propagate into the area. Our cap
is a bit less significant but still higher than previous days so
can`t completely rule out some pop-up thunderstorms during the
afternoon in the wake of whatever MCS/system impacts the region
tonight, but did keep the afternoon hours a relatively lower period
of thunderstorm chances. Storms chances still increase nocturnally
as the surface low lifts into IA and the low-level jet positions
more favorably across the forecast area; however, the jet will also
weaken as the surface low becomes more diffuse, and am still not
incredibly impressed with thunderstorm chances Wednesday night.

Another lobe of surface low pressure will bulge out of the High
Plains on Thursday, helping the retreating dryline sharpen again
across the southwestern High Plains, and likely supporting
convection despite the continued presence of a cap. Convection will
be more isolated as a result, but has a better potential to become
severe west of the area, especially as a substantial upper shortwave
trough begins to push out of the four corners region and into the
High Plains late Thursday afternoon, increasing flow aloft and deep
layer shear. The upper trough and associated surface low will push
gradually to the northeast Thursday night, increasing storm chances
in our area especially after midnight. The best dynamics, shear, and
support for robust storms may remain west of the forecast area on
Thursday, but a few stronger storms can`t be ruled out as elevated
instability avoids being completely diurnally eliminated. Depending
on how quickly Thursday night convection can clear out on Friday and
when exactly the better shear/dynamics associated with the upper
wave aligns across the CWA, strong to severe storms could also
develop near or in our forecast area Friday evening and continue
through the early overnight hours. However, will not spend too much
time discussing this severe potential since it will be highly
dependent on how prior storms evolve.

A slightly quieter weekend is possible after the shortwave trough
pushes out of the region and the longwave trough over the southwest
redevelops; however, moisture, instability, and southerly flow will
linger over the region and cannot completely discount storm chances
continuing through the holiday weekend. Temperatures throughout the
period will depend on rain/cloud cover but should tend towards above
normal readings, especially at night. At least in the next several
days, Wednesday is likely to be the warmest with the least potential
for convective debris lingering around the area during the afternoon.

&&

.Aviation...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 628 AM CDT TUE MAY 24 2016

Storms currently moving through KC area terminals will continue to
push east this morning, and should only reduce vsbys and cigs for 1-2
before departing. A few scattered showers and perhaps an embedded
storm will continue to be possible for a few hours, then a break in
precipitation is expected for much of the rest of the day. Ceilings
should be broken to scattered at 5 kft or greater from late this
morning through the evening hours, then a few storms may build back
into the area early Wednesday morning. Winds will be variable in
direction as storms move through, then should return to south at 10
to 12 kts for the remainder of the period.

&&

.EAX Watches/Warnings/Advisories...
KS...None.
MO...None.
&&

$$

Discussion...Laflin
Aviation...Laflin


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.