Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 231826
AREA FORECAST DISCUSSION
National Weather Service Paducah KY
1226 PM CST MON NOV 23 2015
.SHORT TERM...(This evening through Wednesday)
Issued at 1216 PM CST MON NOV 23 2015
Surface dew points are running drier than modeled this pm,
despite beginning to show signs of waa in our southwest. As a
result, we`ve adjusted immediate near term temps (this pm) upward
and dew points downward accordingly.
This morning we saw mid 20s, to near 30 degrees, for Lows. With
dew points tonight in the u20s-around 30, and weak waa, will go
for Lows in the lower 30s tonight. Visible shots show some high
clouds incoming from the High Plains, that may scatter about our
night-time skies as well.
WAA kicks in a little stronger Tue-Wed time frame. Dew points
shoud be rising through the 30s, to near 40 degrees. Deeper seated
moisture/pcpn will hold off, but the corresponding moistening in
the profile will be warming as well. We`ll see highs rise through
the 50s tmrw, and push 60 degrees for Wed. South winds will pick
up a little better by Wed as the surface high eases off to the
east and a developing rain system approaches from the west.
.LONG TERM...(Thursday through Sunday)
Issued at 226 AM CST MON NOV 23 2015
Higher than average confidence starts off the long term with good
agreement among model solutions. However, confidence takes a tumble
by the weekend with a myriad of solutions offered up by the models.
An upper level low coming onshore over the Pacific Northwest on
Tuesday is forecast to dig into the Intermountain West through mid
week. The low will eventually phase with the main upper level trough
over Canada by late week. Successive perturbations ejecting east
from the low will bring more clouds and eventually rain to the area
during the latter half of the week.
Models continue to trend slower with the onset of precipitation,
which is important since that happens to impact the Thanksgiving
holiday. Right now, the bulk of the precipitation appears to hold
off until after Thanksgiving Day, although a few light showers are
not out of the question by Thursday afternoon, mainly over portions
of southeast Missouri and southwest Illinois.
As low level convergence amplifies ahead of an approaching cold
front, the chance of rain increases from the west Thursday night.
The likelihood for rain showers peaks on Friday before showing some
potential to taper off from the northwest Friday night and Saturday.
Unfortunately, this is where forecast models have really diverged.
Until yesterday, the general consensus was to bring the rain to an
end on Saturday with a return to dry weather by Sunday. However,
more recent model runs shed some doubt on this scenario. For
instance, the 22/12Z ECMWF and 23/00Z GFS clear things out for a
time on Saturday before another slug of overrunning moisture comes
at us by Sunday. Meanwhile, the 23/00Z ECMWF keeps Saturday wet and
shifts rain south of the area by Sunday. Given the lower confidence,
we plan to stick with a model consensus solution, which keeps some
chance in through the entire weekend.
Largely positive showalter indices and a moist adiabatic thermal
profile should limit the potential for thunder. Climatologically
high precipitable water content on the order of 1.25 to 1.5 inches
by Friday signals heavy rain as the main concern with this system.
Best estimate right now is for an average of 1 to 2 inches areawide
Thursday night through Friday night, with locally higher totals
possible, especially in southeast Missouri.
Temperatures are forecast to start off above normal, with readings
near the 60 degree mark on Thanksgiving. Sharply colder conditions
should follow next weekend in the wake of Friday`s frontal passage.
Forecast temperature profiles near Interstate 64 are cold enough
Saturday night that we may need to keep an eye on precipitation
type. However, our best judgment maintains liquid as the dominant
precipitation type through the weekend.
Issued at 1216 PM CST MON NOV 23 2015
Clear skies this pm will yield to a few mid-high clouds tonight.
Soutwest to west winds may occasionally gust this pm, but should
diminish as they become more uniform southerly overnight. Model
time height/cross sections reveal the upper trop moistening works
down to about 700 mb by tmrw morning, so we`ll introduce a sct-bkn
mid deck cig for the planning period, as low level southerlys get
going again during the daylight hours.