225
FXUS63 KPAH 270425
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
1125 PM CDT Thu Sep 26 2024

.KEY MESSAGES...

- Clouds will increase from the east this afternoon and evening.
  A chance of showers and thunderstorms will also spread west
  through the afternoon and evening.

- Widespread showers with heavy rain will set in after midnight
  tonight and continue through Friday evening, as the remnants
  of Hurricane Helene interact with an upper-level storm system
  near the Quad State. Forecast rainfall in this period
  currently ranges from around 2 to 5 inches across the area.
  Some locally higher amounts cannot be ruled out.

- A flood watch and wind advisory have been issued due to
  conditions from the remnants of Hurricane Helene.

- The rains will become lighter and more isolated through the
  weekend.

- The Quad State will begin to dry out on Tuesday as a cold
  front passes. Highs in the 70s and lows in the 50s are
  expected Tuesday through next Thursday.

&&

.DISCUSSION...
Issued at 216 PM CDT Thu Sep 26 2024

All eyes are on Hurricane Helene this afternoon as it heads for
the Florida coast. Locally, we are in the calm before the storm
as high pressure at the surface sits across the Midwest.
Already seeing a tightening pressure gradient across the
southeast which is allowing winds to begin to pick up. Aloft,
an upper level low continues to sit nearly directly over the
area with a downstream ridge axis just offshore the east coast.
The NHC forecasts Helene to make landfall this evening and make
a beeline north into the Tennessee Valley by Friday afternoon.
From there it gets caught up in the upper low across our region
which rotates the remnant circulation around the area into the
weekend. A few scattered showers and storms are possible this
afternoon and evening before the better moisture pushes in late
tonight.

The main forecast concerns for late tonight and Friday will be
potentially heavy rainfall and gusty winds. WPC QPF is generally
around 2-5 inches. There are plenty of signals in the guidance
to support these numbers. The amount of upper level dynamics
involved are impressive supporting plenty of deep layer lift.
There will be plenty of anomalous moisture and moisture
transport in place within strong 850mb convergence atop the area
to support heavy rainfall at times. The best time for heavy
rainfall and the heaviest QPF looks to fall from late tonight
through Friday. The upper low starts to move east and weaken
helping to reduce coverage of showers Friday night into
Saturday. A Flood Watch has been issued for portions of the
area. This flood watch could be expanded further if trends
support it.

There is still some uncertainty surrounding the winds. There
has been a increasing concern for higher wind gusts on Friday.
Forecast wind gust values have increased across the board with
most areas seeing near or above advisory criteria. The pressure
gradient alone should support some of these winds. While
forecast soundings show very poor lapse rates within a saturated
column, just a bit momentum transfer would likely be enough,
and even some of the rain showers may pull down these higher
winds aloft. Confidence has increased enough to support the
issuance of a wind advisory for the entire area for Friday.
Refer to the NPW product for further details.

The system lingers across the Ohio Valley Saturday into Sunday
but should be weakening. On and off rain showers will linger
well into Saturday and by Sunday things will start to dry out.
An upper level trough will dig into the northern plains and
Great Lakes and should kick the remnants of the upper low and
tropical system to the northeast. A cold front will make its way
through the region Tuesday bringing much cooler and continued
drier conditions for Wednesday and Thursday.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1123 PM CDT Thu Sep 26 2024

Rain is steadily increasing across the area and will become even
more widespread overnight through Friday. This will lead to IFR
conditions and possibly lower will through much of the rest of
the TAF issuance. The very heavy tropical downpours will also
lead to reduced visibilities as low as 2 miles or less at times.
Winds are expected to become gusty from the northeast Friday
with gusts reaching into the 25 to 35 kt range.


&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Wind Advisory from 7 AM Friday to 1 AM CDT Saturday for
     ILZ075>078-080>094.
     Flood Watch through Saturday morning for ILZ085>094.
MO...Wind Advisory from 7 AM Friday to 1 AM CDT Saturday for MOZ076-
     086-087-100-107>112-114.
     Flood Watch through Saturday morning for MOZ110>112-114.
IN...Wind Advisory from 7 AM CDT /8 AM EDT/ Friday to 1 AM CDT /2
     AM EDT/ Saturday for INZ081-082-085>088.
KY...Wind Advisory from 7 AM Friday to 1 AM CDT Saturday for
     KYZ001>022.
     Flood Watch through Saturday morning for KYZ001>022.

&&

$$

DISCUSSION...AD
AVIATION...KC