Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 261726
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
1226 PM CDT TUE JUL 26 2016

.UPDATE...
Updated aviation section for 18z taf issuance

&&

.SHORT TERM...(Today through Thursday night)
Issued at 306 AM CDT Tue Jul 26 2016

Already have several locations with LIFR fog as of 08Z. Therefore
have inserted areas of dense fog to all but the far northwest
periphery of the area where skies are mostly cloudy. Will likely
issue an SPS to address the fog potential, but the potential for
clouds to develop over the area early this morning may limit the
extent of dense fog.

The primary surface cold front is nearly stationary near I-70
through Illinois at this time, and is making little progress
southward. The consensus of the 00Z models is for it to enter the
region this afternoon and then shift south of the entire area this
evening. With a very weak pressure gradient over the region it
will be difficult to locate, and confidence in the models is not
great. That said, it will be a focus for convective development
through the period, and will model PoPs around the consensus
placement in the 00Z models.

Aloft the 00Z models open up a weakness in the upper ridge just
west of the region today and tonight. This troughiness along with
the frontal boundary expected to reach southeast Missouri and
southern Illinois this afternoon will keep the focus for good
chance PoPs in the northwest through the day.

Figure that the front is likely to linger over the
southern/southeastern portions of the forecast area tonight into
Wednesday, but with the overwhelming signal in the 00z models
pushing it south of the area, will only have slight chance PoPs
over the region tonight and Wednesday morning. Convection is
expected to become at least scattered over the southern third of
the region Wednesday afternoon, presumably in the vicinity of the
boundary.

The 00Z model consensus sharpens the boundary over west Kentucky
as a mid/upper-level disturbance moves eastward through the region
Wednesday night into Thursday. This should lead to fairly
widespread convection, especially over the eastern half of the
area. Will have likely PoPs for these timeframes. The boundary
will likely remain over the region into Thursday night so will
keep good chance PoPs going then.

There may be enough sunshine over west Kentucky today to allow for
substantial surface destabilization with heat indices potentially
back up near 100. This could support a few stronger storms this
afternoon. Otherwise, plentiful cloud cover through the period
should limit instability and the flow aloft will be too weak to
support any organized severe weather. The primary concerns will
continue to be locally heavy rainfall and lightning. The QPF with
this forecast has amounts from Wednesday through Thursday
of 1-1.5" over west Kentucky and southwest Indiana, with a little
less than an inch elsewhere across the region.

High temperatures will remain near normal today and Wednesday, and
some locations over the southern half of the region may reach
triple digit heat indices. Will settle for mentioning this in the
HWO, and do not have plans to issue an SPS at this time. The
potential for plentiful cloud cover and convection could easily
hold temperatures and heat indices down. The forecast trends
cooler Thursday largely due to clouds and precipitation expected.

.LONG TERM...(Friday through Monday)
Issued at 306 AM CDT Tue Jul 26 2016

Medium confidence in the extended mainly due to the weak flow and
steadfast humid air mass.

After a nearly zonal early in the forecast we will transition into
an upper level trough over the forecast area. This combined with
abundant heat and moisture will be the trigger for thunderstorms
especially in the afternoon and early evening. As the trough slows
or hangs up over the area could expect to see remnants of an mcs
from the north late in the short term combining with a surface
reflection of a cold front should keep a good chance of
thunderstorms over the region. The front will finally drift into the
area Saturday and Sunday then stall out over the forecast area. This
will provide a kicker to fire up thunderstorms over the weekend
albeit weaker than the Thursday Friday scenario. The front will
slowly start to wash out or dissipate early in the work week next
week...decreasing rain chances. Models keep temperatures near or
slightly above normal in the extended but a category or two below
what we encountered last week.  Dew points are also going to be
about 5 degrees below last week. Thus heat advisories or warnings
aren`t expected but it will still remain hot and muggy.

&&

.AVIATION...
Issued at 1226 PM CDT Tue Jul 26 2016

Much like yesterday, scattered storms developed by noon across se
Missouri and parts of srn Illinois. This activity will continue to
slowly increase this afternoon and develop eastward along a weak
outflow boundary. Local ifr vsbys will occur in storms. The activity
will diminish with loss of heating this evening, followed by
reformation of fog and low clouds. The best chance of ifr conditions
early Wed morning will be where heavy rain occurs today. The low
clouds and fog will burn off Wed morning. Winds will be light
through the period, except near thunderstorms.

&&

.PAH Watches/Warnings/Advisories...
IL...None.
MO...None.
IN...None.
KY...None.
&&

$$

SHORT TERM...DRS
LONG TERM...KH
AVIATION...MY


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