Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 061911
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
211 PM CDT Wed Jul 6 2022

.SHORT TERM...(Tonight through Friday night)
Issued at 211 PM CDT Wed Jul 6 2022

The two main concerns through Friday are heat indices and
thunderstorm chances. Model qpf from any model is generally not
very useful in these weakly forced, very moist and unstable
environments. The mesoscale features such as mcv`s and outflow
boundaries are often not detected more than 12 hours in advance.

Within the first 12 hours of this forecast, there is a well-
defined mesoscale outflow boundary to focus on. This boundary was
evident in visible satellite imagery and surface obs from kowb
west into se Illinois as of 19z. A few isolated showers have
formed on the boundary. Through the late afternoon, it is likely
that convection will increase as mixed-layer capes climb to around
3000. Though shear is weak, a pulse type severe storm is
possible, similar to yesterday. Torrential downpours are likely
with slow moving storms in the tropical humidity.

Beyond this evening, mesoscale details become very unclear. The
models are all over the place on the timing and coverage of
convection. The 12z href mean qpf is bullish on convection
Thursday. It indicates a southeastward moving complex that crosses
our region during the day. The forcing mechanism is not readily
apparent, though it appears there will be some low level
convergence. Given the questionable timing and location of any
surface boundaries, broad brush chance pops should suffice for
Thursday. The mid-level flow will be a little stronger over sw
Indiana and southeast Illinois, where pops will be highest.

The highest pops will be Friday afternoon and evening, when a
better defined boundary approaches in the form of a cold front.
This front will arrive Friday night, and likely pops will cover
southwest Indiana and the Pennyrile region of west Kentucky. This
stands to be our best shot at substantial rainfall. WPC qpf is
locally around an inch with this front, however the specific
coverage of heavy rainfall is of course not known.

Heat indices will remain very dangerous through Thursday, barring
the impacts of any mesoscale convective complexes. Though parts of
the area will likely be similar on Friday, the areal coverage and
duration of dangerous heat indices should be reduced by higher
convective coverage.

.LONG TERM...(Saturday through Wednesday)
Issued at 211 PM CDT Wed Jul 6 2022

The upper level pattern during this period will feature a dominant
ridge across the southwestern U.S. and troughing across the
northeast U.S.

Saturday will be a transition day. Models differ on exact timing of
the cold front, but generally expect the switch to northerly winds
to occur by 18z everywhere. However, convection may linger post
frontal with low level moisture slower to depart. The north half of
the region may be dry by midday, but we may still contend with
scattered activity in our south half through the afternoon and
possibly into early evening.

Dry conditions are expected Saturday night through Monday night.
Lower humidity will also work into the region with dewpoints down
into the lower half of the 60s on Sunday. This will allow overnight
lows to drop into the 60s. Highs over the weekend look to be in the
mid to upper 80s.

On Monday and Tuesday, the 850mb thermal ridge that was shunted to
the south and west on Sunday will sneak back overhead with values
over 20C again. This will lead to a spike in high temperatures back
into the low to mid 90s. Guidance continues to suggest some rain
potential with a cold frontal passage on Tuesday. Ensemble data
isn`t all that impressive with it at this time though.

Mid to late next week, a more pronounced 500mb trough is expected to
dive into the Ohio Valley with ensemble 850mb temperatures shown to
lower closer to 15C. This would likely lead to temperatures below
normal in the low to mid 80s for highs later next week.

&&

.AVIATION...
Issued at 1204 PM CDT Wed Jul 6 2022

Mainly vfr conditions will continue through the taf period. There is
some potential for organized thunderstorms this afternoon in
southwest IN, northwest KY, and southern IL. Satellite loops show an
outflow boundary moving through sw Indiana and se Illinois as of
17z. Some thunderstorms will likely develop on this boundary as it
crosses nw Kentucky, and these storms could backbuild into srn IL
and southwest IN. This has been handled with vcts in the upcoming
tafs.

Mainly clear skies are expected tonight into Thu morning. Winds will
be mainly west to southwest 5 to 10 kt during the day, and light
south at night.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Excessive Heat Warning until 9 PM CDT Thursday for ILZ075>078-
     080>094.

MO...Excessive Heat Warning until 9 PM CDT Thursday for MOZ076-086-
     087-100-107>112-114.

IN...Excessive Heat Warning until 9 PM CDT Thursday for INZ081-082-
     085>088.

KY...Excessive Heat Warning until 9 PM CDT Thursday for KYZ001>022.

&&

$$

SHORT TERM...MY
LONG TERM...SP
AVIATION...MY


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