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

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FXUS63 KEAX 161132

632 AM CDT Tue Sep 16 2014

.SHORT TERM...(Today through Thursday Night)
Issued at 335 AM CDT TUE SEP 16 2014

Fairly quiet today as high pressure remains in firm control of the
weather pattern. With this feature to our north...expect continued
northerly to northeasterly winds through the day which will help keep
temps anywhere between 5-10 degrees below normal. In general...highs
this afternoon should warm into the middle to upper 60s across most
areas...with low 70s possible across the far south and southwest. All
good things come to an end and that trend will start tonight as
yesterday/s frontal boundary begins to lift back north as a warm
front in a developing warm air advection regime. Quick look at
several isentropic surfaces reveals decent lift in the 300-305k layer
with condensation pressure deficits showing minimal lift required for
saturation. Meanwhile aloft...fcst models in excellent agreement that
a weak 850-hPa circulation will move overhead which combined with
passing mid-level shortwave energy and a modest 25-30 kt swrly
LLJ...should set the stage for redeveloping shwrs/storms during the
late evening and predawn hrs. Considering upper jet dynamics look
poor...have capped pops in the mid chc range across the western third
of the fcst area...with slgt chc largely reserved for areas east of
Route 65. Cannot rule out some isolated stronger storms as MUCAPE
values exceed 1000 J/kg and 0-6 km shear increases to roughly 30-35
kts. This combination could support a few elevated storms capable of
marginally severe hail.

On Wednesday...aforementioned frontal boundary to make little
eastward progress thanks to well entrenched high pressure across the
Ohio Vly/central Great Lakes. Continued northwest flow aloft will
allow additional shortwaves to traverse the area...however AM activity
should slowly slide south throughout the day as LLJ veers and weakens
through the period. Despite this...decent low-level frontogenesis
combined with diurnal instability will allow for additional activity
through the afternoon and thus maintained slgt chc-chc mention with
highs generally warming into the lower to middle 70s.

Much the same Wednesday night into Thursday as frontal boundary
remains in place. Overall precip coverage early Thursday morning
looks to be less than Wednesday as a much weaker LLJ interacts with
the stalled front. Have maintained chc mention overnight before
decreasing pops to slgt chc on Thursday. Temps should continue
rebounding Thursday as heights slowly build in advance of mid-level
low pressure developing over the western U.S. This should result in
mid to upper 70s across most areas...with a few low 80s not out of
question across the western third of the CWA.

.LONG TERM...(Thursday Evening through Monday)
Issued at 335 AM CDT TUE SEP 16 2014

Friday: Upper level ridging will build into the area on Friday, with
southerly winds and moisture returning. High temperatures on Friday
will be the warmest of the 7-day forecast, with readings reaching
the lower to middle 80s across the CWA.

Saturday/Saturday Night: The upper trough over the Pacific coast
will move into the central CONUS on Saturday, with the remnants of
the tropical system Odile projected to track across eastern Kansas
into central Missouri. A strong low-level jet will develop ahead of
these systems Friday night into Saturday morning, advecting deep
moisture northward. Forecast precipitable water values across the
CWA are expected to be near 2 inches, which is two standard
deviations above the climatological normal. Strong upper ascent from
the approaching trough combined with deep tropical moisture will
yield the potential for locally heavy rainfall for portions of the
forecast area Saturday into Saturday night, along and ahead of a
cold front. Average precipitation totals should range between
one-half to one inch, with locally higher amounts upwards of 1.50".
Specific rainfall totals and the location of the heaviest rainfall
will continue to be refined as the event approaches.

Sunday and beyond: Precipitation should shift out of the forecast
area by Sunday morning, with mostly sunny skies and northerly winds
behind a cold frontal passage. A large upper trough will amplify
over the eastern CONUS by early next work week, keeping the CWA in
northerly flow, and placing temperatures back into below normal


.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 632 AM CDT TUE SEP 16 2014

Early morning radiation fog at STJ will quickly burn off by 14z as the
daytime heating cycle commences. In its wake...VFR conditions to
dominate through much of the day as high pressure slowly slides east
of the region. Clouds will be on the increase overnight as a frontal
boundary lifts north towards the area. Fcst models show developing
convection after 6z...however will leave mention out for now based
on distance into the fcst period. Winds through the period will
remain from the east between 4-8 kts.




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