000
FXUS63 KEAX 130454
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1154 PM CDT Wed Jun 12 2013

.SHORT TERM...(This Evening through Friday Night)
Issued at 334 PM CDT WED JUN 12 2013

Another hot and humid day across the region ahead of a frontal
boundary just beginning to cross the CWA this afternoon.  Fairly
widespread CU field ahead of the surface front has tempered
temperatures a degree or two, but most areas still reaching the
lower 90s.  The primary weather story will be focused on the
unfolding severe weather event over the Great Lakes and Ohio River
valleys as a compact but intense shortwave begins to move eastward.

As this upper level wave moves eastward, it will finally push the
frontal boundary through the region this evening.  19Z sounding out
of KCI indicated a large cap still remains in place this afternoon
with 700mb temps around 15C-16C, RAP/NAM plots suggest the edge of
this cap likely resides over extreme northeastern Missouri and is
expected to remain in place as this upper wave moves away this
evening. Thus, will continue with a dry forecast for most overnight,
leaving only a slight chance for a thunderstorms in the northeastern
CWA this evening as cooler air aloft tries to move in overhead the
surface boundary this evening.

Thursday:  High pressure will slide southeast through the area
cooling temperatures off by 10 or more degrees in some locations.
GFS/NAM advertise a weak shortwave ejected out of the Rockies which
in return induces a focused area of isentropic lift along the
312-315K surfaces in north central Nebraska and northern Kansas. The
development of high based showers seems plausible, with moisture
fairly limited below 700mb. What is possible is some impact on
temperatures by cirrus and mid-level clouds associated with this
development.

Thursday night-Friday: A series of shortwaves will try to overtop the
ridge beginning Thursday night and continuing into Saturday morning.
Model guidance suggests sufficient isentropic lift focused ahead of
these waves to produce several bands of showers and thunderstorms,
primarily focused over Iowa, Nebraska, and the northern portions of
Missouri. Temperatures on Friday may be slightly problematic given
potential for influence of cloud cover and cooler easterly flow from
high pressure in the Great Lakes. Western zones could climb near 90,
with the northeastern and eastern areas stuck in the upper 70s.

.LONG TERM...(Saturday through Wednesday)
Issued at 334 PM CDT WED JUN 12 2013

Not much has changed with respect to this weekends weather over the
past 24 hours as the medium range models continue to depict sultry
conditions with a good chance of seeing a couple rounds of
thunderstorms.

The period will start off with an upper level ridge over the nations
mid-section which will be flattened as it shifts eastward by a
northern stream upper trough and a shortwave lifting northeast
through the Southern Plains. As the upper level ridge axis passes by
the southwest flow on the backside of the feature will allow an
influx of deep subtropical moisture to flow northeast and spread
across the CWA. In addition a moderately strong shortwave, which all
of the models agree on, is expected to lift northeast. Timing places
the leading edge of PVA and better dynamics reaching western MO by
Saturday evening so favor likely PoPs. Have pared back PoPs some for
Saturday, especially over the southern half of the CWA Saturday
morning. Afternoon hours could see random pulse-type convection due
to moderate instability. Low-shear environment places a low, but
non-zero, severe risk during the afternoon hours. Above average
temperatures and humidity expected with highs topping out near 90
over the western counties.

Sunday will be a challenge in many ways including rain chances as
the combination of either on-going convection at the start of the
day and/or numerous left-over convective boundaries will make it
difficult to time and located convection. Once again we may have a
situation in the afternoon hours where pulse-type convection will
reform. Temperatures will be determined by degree of cloud cover and
convection. So, model consensus is the best way to go. Sunday night
could see another convective complex roll east off the eastern
slopes of the CO Rockies and track into the CWA. The ECMWF, GFS and
GEM are very similar in developing this feature.

Due to the expected deep sub-tropical moisture plume that will be in
place over the weekend the potential for localized heavy rainfall
will exist.

The start of next week is looking less decisive for convection as
the upper level ridge reforms over the High Plains in response to a
shortwave dropping southeast through the Great Lakes and a
large/deep upper trough plowing into the Pacific Northwest. So,
lacking conviction on seeing any organized convection have backed
off on PoPs to slight chances.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1148 PM CDT WED JUN 12 2013

VFR conditions will prevail through the next 24 hours. Only thing to
watch will be the wind shift as the direction veers from the
northwest around to the east by Thursday evening. Once gusty winds
subside tonight, speeds are then expected to remain under 10 knots.
Otherwise, there is a chance of thunderstorms just beyond then end of
this TAF cycle.

&&

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

$$

SHORT TERM...Dux
LONG TERM...MJ
AVIATION...Cutter