Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 011721
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
1221 PM CDT Mon Sep 1 2014
Issued at 1221 PM CDT MON SEP 1 2014
Updated the AVIATION section.
UPDATE Issued at 849 AM CDT MON SEP 1 2014
Clearly evident yesterday`s and even some of last night`s models
were unable to resolve and capture several ongoing elements. PoPs
have been modified to capture ongoing convection over the east
that wasn`t model depicted prior. Also, winds were up quicker than
forecast this morning. 12z upper air data shows 30-40kt low level
jet already established. Thus, that leads us to the fact we are
already at Lake Wind Advisory criteria. Given it`s the holiday,
will go ahead with one. Gusty southwest winds expected 10 to 20
mph with 25+ mph winds possible at times. Not necessarily the
optimum trajectory, but quite breezy none the less. Meanwhile,
kept chance of convection going more aggressively than previously
forecast, given the amount of heating we will see ahead of the
decaying activity to our west. The HRRR shows some development in
this region of less cloud cover over the next several hours,
before dying off later in the afternoon. Will see if this actually
comes to fruition. For now, will keep PoPs in the chance category.
.SHORT TERM...(Today through Wednesday)
Issued at 200 AM CDT MON SEP 1 2014
MCS dropping down across MO will spread its clouds into/across PAH
FA this morning. It will also lay out some boundaries, the primary
one of which lays out across our northern tier this afternoon,
where we`ll have a slgt/small chance mentionable Pop.
As the mean energy in the long wave moves across the MS and Wabash
river valleys tonight and Tuesday, it will drag this primary
boundary into the heart of the FA and result in an uptick in Pops
to likely cat or better, particularly during the day Tuesday. This
has been a consistent model signal and looks a good bet with fropa
thru much of the area by 00Z Wed.
The front/boundary hangs up across our southern tier or just to
the south Tue night, and returns as a warm sector boundary late
Tue night and Wed. This is indicated by several model members so we
adjusted Pops accordingly.
Temps look to remain summerlike at or just above climo norms from
the mid/upr 80s to near 90 for highs, and generally in the
u60s/lower 70s for lows, with continued muggy dew points.
.LONG TERM...(Wednesday Night through Sunday)
Issued at 302 AM CDT MON SEP 1 2014
The PAH forecast area will be under the stabilizing influence
(aloft) of a broad mid level ridge late in the week, though some
models indicate that, with the substantial diurnal lower trop
instability present each day, some deep moist convection may be
strong enough to get past the warm mid level cap in some locations
during the daytime.
Meanwhile, a nrn stream longwave trof will be in the process of
lowering mid level heights across most of the CONUS. A sfc cold
front is forecast to sink sewd into the OH river valley by sometime
early Sat, with some timing differences among the med range models.
This feature will provide additional focus for lifting of abundant
moist air, thus PoPs are now 40-50 percent during the day Sat behind
the front. By Sunday, a drier air mass should be making its way into
our region, cutting off pcpn. However, the GFS and its ensemble
means suggested the center of the high (over the upper Midwest) may
be farther east than the ECMWF and its ensemble means indicated, and
therefore some warm advection showers/tstms may erupt just to our
west. We will have to wait and see how long the drying effects of
the dome of high sfc pressure actually last.
Warm and humid conditions will prevail late in the week ahead of the
front, with heat indices peaking around 100 Thu and Fri, but
especially Fri. For this forecast package, the frontal passage
should provide us end-of-the-weekend dewpoints in the 60s along with
Issued at 1221 PM CDT MON SEP 1 2014
Prob of convection not high enough to include at the Terminals this
afternoon. Gusty SW winds will persist, 10-20kt +. Ocnl clouds aoa
12k/ft will continue, with sct-bkn025-035 expected, gradually
higher bases with time. Kept best chance of convection tonight,
within Prob30`s mainly aft 06z as convective chances increase
markedly after midnight. Winds will back to the south and fall to
aob 10 kts tonight.
IL...LAKE WIND ADVISORY until 6 PM CDT this evening FOR ILZ075>078-
MO...LAKE WIND ADVISORY until 6 PM CDT this evening FOR MOZ076-086-
IN...LAKE WIND ADVISORY until 6 PM CDT this evening FOR INZ081-082-
KY...LAKE WIND ADVISORY until 6 PM CDT this evening FOR KYZ001>022.