Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 042347

Area Forecast Discussion
National Weather Service Paducah KY
647 PM CDT Tue Aug 4 2020

Issued at 646 PM CDT Tue Aug 4 2020

Updated aviation discussion for 00Z TAFs.


.SHORT TERM...(Tonight through Thursday night)
Issued at 312 PM CDT Tue Aug 4 2020

In the upper levels of the atmosphere, not much has changed in the
last 24 hours. A large upper level low continues to sit and churn
over eastern Ontario/northwestern Quebec, with a strong ridge in the
west, centered over the Four Corners Region. At the surface, high
pressure has been steadily building into the area today and weak
cold/dry air advection continued through the morning and early
this afternoon. At 3pm, we have dewpoints down in the upper 50s in
many locations, which is a nice change from the humid conditions
as of late.

We will continue to see the drier air filter into the area through
tonight. Consensus of the latest short term models indicates that
dewpoints could drop as low as the upper 40s to lower 50s in our far
northern areas, which will translate to somewhat chilly low
temperatures tonight. This will be especially true in locations
along and north of the I-64 corridor, like Mt. Vernon, which will
be closest to the center of the surface high. Guidance is
suggesting anywhere from 50 to 55 degrees at KMVN. Nonetheless,
lows tonight will generally be in the 50s with lower to mid 50s
north to upper 50s south.

With a similar airmass in place across the area on Wednesday,
expecting highs like today, ranging from the upper 70s to lower
80s. The amount of low level moisture should be decreasing with
time, but will likely be enough for some decent cu development.

After another night in the 50s, we will see another dry but warmer
day on Thursday, as high pressure remains in place. We will start
to see some warmer air advect into the area, as upper heights
rise and the upper flow over us becomes more zonal, in conjunction
with the upper low in eastern Canada finally moving eastward. In
general, expecting high temperatures rising into the lower 80s
areawide, with the warmest readings in parts of southeast MO where
readings could reach into the mid 80s.

.LONG TERM...(Friday through Tuesday)
Issued at 312 PM CDT Tue Aug 4 2020

At the start of the extended forecast period, an upper-level trough
will be positioned in the Midwest while a ridge will be centered in
the Central Plains. This will direct northwesterly flow aloft
towards the Quad State. A surface high in Michigan will produce
northwesterly flow at the surface east of the Mississippi River and
a more southerly component west of the Mississippi. More moisture in
Missouri, coupled with a smaller scale disturbance, will produce
showers and storms over Missouri Thursday. However, as the
disturbance approaches the Quad State, it will be weakened greatly
by the dry air over the Quad State associated with the high
pressure, leaving only a slight chance of precip Friday morning for
the westernmost counties of Southeast Missouri. This has been
consistent in the models for several days now with only a one county
shift westward in extent.

The high pressure will move towards the east on Friday, and along
with it the trough will retreat northwards, slowly increasing 500-mb
heights. Additional minor disturbances will move towards the Midwest
via the west-northwesterly flow. Their timing and strength vary
among the models though there has been a slight northward shift in
the storm track compared to previous model runs. This has lowered
some of the PoPs for the weekend. However, with southerly surface
flow, there will be moisture to work with if there is a decent
source of instability available.

Temperatures and dew points will continue to trend upwards a couple
degrees a day until the weekend. At that point, high temperatures
will resemble average, near 90, while low temperatures will be
slightly above average in the lower 70s as humid conditions


Issued at 646 PM CDT Tue Aug 4 2020

VFR conditions are expected through Wednesday with scattered to
occasionally broken VFR cumulus by Wednesday afternoon. Some
patchy fog is possible late tonight, but a light north-northeast
wind should mitigate its development to a large degree.




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