000
FXUS63 KEAX 190821
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
321 AM CDT Wed Jun 19 2013

.SHORT TERM...(Today through Thursday Afternoon)
Issued at 321 AM CDT WED JUN 19 2013

Quiet, dry weather should persist through at least the morning hours
today as surface high pressure drifts southward, then scattered
storms will become a concern as a shortwave trough approaches from
the west. A small, weak perturbation in the midlevel height field
could combine with residual outflow boundaries from overnight
convection in central KS to fire up a few storms by early afternoon,
which could then move eastward into the region by mid to late
afternoon. Warmer temperatures are expected this afternoon as
southerly winds develop on the back side of the departing surface
high, which will also result in decent destabilization and could
possibly support thunderstorm chances this afternoon and evening.
These storms, if they form, will be diurnally driven and should
dissipate shortly after sunset. Severe weather looks unlikely for
our area, with the better flow/shear remaining well to the west and
at least some CIN hanging around at ~800 mb.

The main shortwave trough will arrive later tonight, increasing
thunderstorm chances from west to east between midnight and daybreak
Thursday. However, the probability of of showers and thunderstorms
continuing during the day on Thursday is somewhat complicated, with
significant differences in how the models handle another shortwave
trough creeping up ahead of the main ridge axis in eastern Kansas.
The NAM currently resolves this secondary wave as a strong enough
feature to temporarily flatten the top of the entering ridge,
allowing another round of convection to form late Thursday morning;
however, the GFS keeps the wave much weaker and doesn`t produce much
additional chance for precipitation after the first wave exits the
region early Thursday morning. For now, have stuck with chance PoPs
through the morning hours and then decreased and pushed any chance
of storms eastward for the afternoon. The spatial and temporal
coverage of precipitation will also impact high temperatures, which
may be a few degrees too cool if all storms shift out by mid-morning
and allow clearing over the area.


.LONG TERM...(Thursday Evening through Tuesday)
Issued at 321 AM CDT WED JUN 19 2013

Models are forecasting a very moist airmass in place on Friday while
temperatures rise into the lower 90s, leading to heat index values
near or slightly above 100. This also will lead to strong to extreme
instability across the region with models showing little capping
inversion in place. While forcing will be weak, it wouldn`t take
much to spark a few thunderstorms during the afternoon, and several
models hint at a weak impulse that could kick off thunderstorms
Friday afternoon and evening. Therefore PoPs were bumped up into
low-chance category despite only a few models producing
precipitation.

Upper pattern will undergo relatively little change through the
remainder of the extended period with broad ridging over the Midwest
and mean troughing over the Rockies and Northern Plains. This will
maintain warm temperatures with afternoon heat index values flirting
with 100 degrees each day through Tuesday. Airmass will remain
unstable each afternoon which could lead to isolated storms Saturday
through Monday. Capping will increase by early next week which
should keep conditions dry by Tuesday.


&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1225 AM CDT WED JUN 19 2013

Scattered to broken midlevel clouds will stream into the western half
of the region tonight, but conditions are expected to remain VFR with
bases generally above 8,000 to 10,000 ft. Patchy fog may continue to
form over north central Missouri tonight, but is not expected to be
widespread. Thunderstorm chances will begin after 21z Wednesday, but
the probability of storms at any one location are still low. Winds
will increase out of the southeast after sunrise, and will remain
sustained out of the SSE at 10 to 15 kts Wednesday afternoon and
evening.


&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&

$$

SHORT TERM...Laflin
LONG TERM...Hawblitzel
AVIATION...Laflin