Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 211201
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
701 AM CDT Mon May 21 2018

.UPDATE...
Issued at 701 AM CDT Mon May 21 2018

Updated aviation section for 12z TAF package.

&&

.SHORT TERM...(Today through Wednesday night)
Issued at 314 AM CDT Mon May 21 2018

Widespread convection currently pushing north into southeast
Missouri extends southward through all of eastern Arkansas and
into central Mississippi. The latest HRRR data stream the
convection northward through southern Illinois and the Purchase
Area through daybreak, and then slowly diminish it through the
morning. Instability will be difficult to find over our region
early this morning, so thunder will be limited.

The early morning convection and associated cloud cover will tend
to hold down temperatures, with most of the area not climbing out
of the lower 80s this afternoon. The consensus of the 00Z
guidance is a few degrees cooler than the previous forecast for
highs this afternoon.

Wind fields will be quite weak this afternoon, and destabilization
may be difficult to achieve. If we get some at least filtered
sunshine this afternoon, some pulsy strong to severe storms will
be possible, but SPC`s Marginal Risk may be a bit of a stretch.
The moisture-laden atmosphere will continue to support locally
heavy rainfall, but the pulsy nature of the convection will limit
the flash flood potential.

Not sure how much convection will remain after 00Z this evening.
Will keep small chance PoPs going for most of the area tonight,
but there may not be much at all until a weak cold front sags into
the area toward daybreak Tuesday. This boundary will provide a
focus for convective development as it sags southward through the
area Tuesday. 500mb Heights will be on the rise Tuesday, and that
should limit instability. Figure on some pulsy, disorganized
storms with little severe potential. Once again copious moisture
available will lead to some locally heavy rainfall potential.

High pressure at the surface and aloft will prevail from Tuesday
night through Wednesday night. The forecast for these periods is
actually dry, but we will still see highs in the middle 80s and
lows in the middle 60s.

.LONG TERM...(Thursday through Sunday)
Issued at 314 AM CDT Mon May 21 2018

Models are in decent agreement taking a front, originally forecast
to hang up just south of the PAH forecast area, far enough south to
keep us mainly dry Thursday into Friday night.  There are a few
hints that isolated convection is not out of the question in our far
southern counties Friday afternoon, but based on the models
southward trends, will keep these areas at or just below 14 percent
for now.

As we get into the weekend, ECMWF and the Canadian show a low
pressure system coming up through the central Gulf. This will help
pump up additional low level moisture into the middle Mississippi
and lower Ohio valleys.  This moisture, combined with an approaching
cold front, will lead to increasing shower and thunderstorm chances
Saturday, with isolated to scattered convection possible into mainly
the evening hours.  Daytime heating on Sunday will again give us
isolated to scattered thunderstorm chances as the cold front moves
into the PAH forecast area.  We will have to continue to watch the
Gulf low track and see how it affects the movement and timing of the
cold front and our convection chances.

Our unseasonably warm air mass will be well established for the end
of the work week, so despite easterly flow on Thursday, highs will
still reach the middle to upper 80s.  Readings will be a degree or
two higher on Friday with the return of the moist southerly flow.
These conditions will continue into the weekend with dew points
near to around 70 degrees at times.

&&

.AVIATION...
Issued at 701 AM CDT Mon May 21 2018

Scattered shra/tsra possible through the day, with mainly showers
in the morning and better chances of thunderstorms this afternoon
into early this evening. Chances will decrease at all sites after
00z. MVFR conditions are possible with precipitation, otherwise
VFR conditions will be predominant. Winds will be from the south
to southeast at 5 to 10 kts, decreasing to 5 kts or less after
00z.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&

$$

SHORT TERM...DRS
LONG TERM...RST
AVIATION...RST



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