Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 160948
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
348 AM CST Mon Dec 16 2013
.SHORT TERM...(Today through Wednesday)
ISSUED AT 348 AM CST MON DEC 16 2013
Low clouds have cleared much of the region early this morning,
with the exception of perhaps a few locations in the Evansville
tri-state area. The low clouds were replaced by mid level clouds
accompanying the passage of a mid level disturbance overnight.
Model guidance indicates these clouds should clear the region from
west to east through the morning. Some redevelopment of low clouds
is possible by late morning and afternoon with lingering low level
moisture still in place. However, their impact should gradually
lessen as we progress towards mid week.
Over the last 24 hours, we have expressed some concern for fog
development for the next few nights as low level warm advection
develops over top a cold moist snow covered ground. Despite what
some raw model guidance was suggesting last night, little to no
fog has formed over southeast Missouri thus far. Winds have stayed
up overnight, but this should not inhibit the advection fog
process we thought might occur. The air advecting into the region
from the southwest is relatively dry, so that may be an inhibiting
factor to fog formation instead, especially with a persistent
light southwest wind. Similar conditions are expected tonight, so
fog will hopefully not be much of an issue. Tuesday night may be
a different story as light winds beneath a clear sky create more
favorable conditions for radiation fog, particularly where any
snow cover still exists. Low confidence precludes a mention in the
forecast at this time - just something to keep in mind nonetheless.
Below normal temperatures will persist today as the region remains
in northwest flow aloft on the back side of a longwave trough over
the east. However, a transition to a more zonal flow pattern by
mid week will help to slowly moderate temperatures through the
period. Highs by Tuesday should top the 40 degree mark in most
locations, and possibly reach close to 50 degrees over southern
portions of the area. Highs on Wednesday are expected to range
from the upper 40s to mid 50s. Weak energy rotating across the
Great Lakes may keep more sky cover in our northeastern counties
through Tuesday, but this influence will lessen by Wednesday with
more sunshine across the entire region.
.LONG TERM...(Wednesday Night through Sunday)
ISSUED AT 119 AM CST MON DEC 16 2013
We start the long term portion of the forecast with subtle shifts
in the pattern that will lead to a moderation in temps. The upper
level flow will be backing, as height falls in the southern Plains
occur in response to a digging upper level jet. Downstream ridging
will work in as upper level southwesterlies aid the moderation
By Thursday, this moderating trend includes moisture, and
elevated/overrunning pops begin to appear from the north and west,
as a front will be taking shape and approach from that direction.
Thursday night-Friday, we see surface dew point temps surging
through the 50s, with 60F not far off. 850 mb winds have increased
to 50 kts. Elevated instability parameters such as the K index
suggest at least an isolated mention of thunder is still possible.
Beyond Friday is where the model divergence takes place. However,
despite the differing solutions, a trend of warmer layer threshold
temps is starting to appear, as both the ECMWF/GFS have trended
this direction the last two forecast nights. The ECMWF keeps a
wetter forecast as the boundary still sets up/hangs in the vcnty
thru the weekend, while the GFS moves it on thru before
stalling/returning it. Both suggest mainly liquid pcpn chances by
and large as a whole, although both also support a changeover
before ending mention by late day 7 into day 8.
ISSUED AT 119 AM CST MON DEC 16 2013
Lingering IFR cigs at KEVV/KOWB should move out soon. Broken mid
level clouds are expected otherwise with occasional MVFR vsbys possible.
After 14z, VFR conditions are expected through the day. Winds will
be south to southwest at 5 to 10 kts through the TAF period.