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

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615
FXUS63 KEAX 131113
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
613 AM CDT Sun Aug 13 2017

.Discussion...
Issued at 405 AM CDT SUN AUG 13 2017

High pressure over the southern Great Lakes continues to extend
surface ridging over the region this morning which helped keep the
MCS over Nebraska from entering our area.  This high will shift
south today weakening this ridge and allowing a more southerly flow
to develop over the region.  An upper level shortwave and nocturnal
LLJ Sunday night into Monday will help develop another MCS over Iowa
that may help spark some elevated convection and showers over
northern Missouri early Monday morning.  The southerly flow over the
region will also increase the dewpoints almost 10 degrees higher
Monday afternoon creating the potential for some afternoon
thunderstorms over northern Missouri where the capping inversion
will be weaker. Marginal SBCAPE values and weak shear conditions
indicate the storms will remain sub-severe.

A strong upper level shortwave over the west coast will help to
develop ridging over the area on Tuesday keeping most of the CWA
precipitation free through the early afternoon. The continued
southerly flow in the low levels will keep the warmer and more humid
conditions in place with heat index values reaching into the mid 90s
for the first time in a while and actually feel like August in
Missouri. As this shortwave progresses east a large area of lower
pressure and warm frontal like boundary will form over eastern
Kansas Tuesday evening.  This boundary will be reinforced by a
strong LLJ over central Kansas brining the possibility of elevated
convection into the region Tuesday night into Wednesday.  High
MUCAPE values over 3000J/kg could help to create a possible large
hail threat from these elevated storms, but shear will be relatively
weak to marginal keeping the severe threat somewhat limited. This
elongated area of low pressure will eventually develop into a mature
low pressure system with the parent low over MN and a cold frontal
boundary extending down into our northern CWA Wednesday into
Thursday.  This boundary will push through the area providing
forcing for scattered thunderstorm development in which some of
these storms could become strong to severe with high CAPE values
greater than 3000J/kg and marginal shear values near 30kts. The cold
front will not push through until Thursday morning culminating in
multiple rounds of storms to form over most of our area and QPF
totals between 1-2". Models differ slightly Thursday afternoon with
the GFS indicating the front will go south of our CWA while the
ECMWF has it stall in central MO.  With this uncertainty only chance
PoPs have been left in the southern area of our CWA for Thursday.
Temperatures do not drop much for the weekend with this cold front,
but dewpoints drop making it feel much more comfortable. Another
shortwave will push into the area Friday afternoon bringing the
chance for storms back into the area, mainly along the MO River and
south through Saturday morning before it clears out in the
afternoon.

&&

.Specifics for the Total Solar Eclipse on August 21st...
Issued at 405 AM CDT SUN AUG 13 2017

GFS and Canadian models are still trying to suggest a weak
shortwave over the area Sunday night into Monday with nocturnal
convection over the KS/MO border lingering into the afternoon
Monday. The 00z runs did however start to show a larger ridge
building over the central plans behind this weak shortwave with
less of a zonal flow than they have had the last few runs and
coming more in line with the ECMWF solution of a ridge over the
northern plains. This is the first trend towards a less cloudy
solution in the last few runs and does give some hope for a less
cloudy solution for the region than it previously had.

&&

.Aviation...(For the 12Z TAFS through 12Z Monday Morning)
Issued at 612 AM CDT SUN AUG 13 2017

VFR conditions will continue throughout the period with ceilings
around 4,000ft forming up in the afternoon, but dissipating after
sunset. Winds will remain out of the southeast at 5-10kts
throughout the period.

&&

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

$$

Discussion...Barham
Aviation...Barham
Eclipse...Barham



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