Area Forecast Discussion
Issued by NWS Paducah, KY

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717
FXUS63 KPAH 172323
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
620 PM CDT SUN JUL 17 2016

.UPDATE...
Updated aviation section for 00z taf issuance

&&

.SHORT TERM...(Tonight through Tuesday night)
Issued at 209 PM CDT Sun Jul 17 2016

Very near term...Convection showing up just north of CWA. It is
having a hard time building further south, where capping temps are
advecting in from the southwest. However, there is a possibility
we could get skimmed in or on our northern counties, esp as they
move east. Will monitor this closely thru press time.

Looking just a bit further out, the broad High Pressure
circulation aloft ridges nicely across the country`s mid section,
and we see a strong H5 height rise, esp into our southwest FA,
with 597+ DM building in. This will taper Monday-Monday night
Pops, from slgt or nil southwest, to highest northeast, closer to
the nice piece of H5 energy making passage across the middle-upper
Ohio river valley. A marginal risk of SVR storms continues there,
in our northeast.

Getting into the close of the short term (Tuesday), the H5 High is
holding and strengthening, to 599 DM over SGF area. But this
actually turns our flow aloft to a more nwly, and active
component, so we`ve upped Pops Tuesday, esp across our central and
northeast counties. It might be capped still, eliminating or
minimizing the Pops in our southwest (SEMO Ozarks), closer to the
High center.

Each of the next two afternoon`s will see a combo of heat/humidity
that produces Heat Indices nearing or into the Triple Digits, so
we`ll continue our SPS for that hazard.

.LONG TERM...(Wednesday through Sunday)
Issued at 209 PM CDT Sun Jul 17 2016

Confidence is quite high in a stretch of hot and humid conditions
through the extended portion of the forecast.

A rather amplified area of high pressure aloft will be centered over
the central/southern Plains into the Ozarks on Wednesday. At the
surface, high pressure will be in control. The upper high/ridge will
gradually flatten and stretch from the desert southwest toward the
southeast coast, as the flow aloft become nearly zonal across the
northern Plains and Great Lakes through Friday. Meanwhile, the
surface high will shift east, allowing south winds to return
Thursday. The ECMWF is preferred, so expect high pressure aloft and
southerly surface winds to continue to support the heat and humidity
through next weekend.

Isolated thunderstorms cannot be ruled out in the heat of the day
throughout the period. However, no organized convection that would
provide significant relief from the heat is expected. The 12Z GFS
does try to bring a boundary of some sort into the area next
weekend, but that seems a bit of a stretch given the upper flow
pattern. However, it will result in small chances of thunderstorms
being forecast for much of the region over the weekend.

Guidance has trended a little less robust with the cooling and
drying trend in our northeast Wednesday. It now appears that highs
over the Evansville Tri State will reach the lower 90s with
dewpoints not dropping significantly below 70. Triple digit heat
indices are very likely throughout the area Thursday through next
Sunday, with highs in the middle 90s and dewpoints in the lower to
middle 70s. A Heat Advisory is likely to be needed for much of next
week and into next weekend. Even if some locations do not quite
reach 105 each day, four continuous days of 100 or greater would
also require a Heat Advisory. If Wednesday does not provide any
relief, we could be looking at a week or more of triple digit heat
indices for much, if not all, of the region.

&&

.AVIATION...
Issued at 620 PM CDT Sun Jul 17 2016

Generally vfr conditions will continue this taf period. Southwest
winds in the 10 to 20 knot range will continue just off the surface.
These winds should keep fog or haze from becoming a concern tonight.
Of more concern is the possibility of a thunderstorm complex late
tonight or Monday, especially in the kevv/kowb areas. Mesoscale
model guidance is in fairly good agreement that a storm complex will
move southeast from the upper Mississippi Valley to the southwest
Indiana area after 08z tonight. If such a complex develops this
evening, thunder will likely be added to the forecast for the early
morning hours.

&&

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

&&

$$

Aviation...MY



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