Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 221124
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
625 AM CDT Wed Oct 22 2014
Updated aviation section for 12z tafs
.SHORT TERM /Today through Friday night/...
Issued at 305 AM CDT Wed Oct 22 2014
Today will be another sunny day for most of our region. There may
be some afternoon cumulus clouds again in southwest Indiana and
adjoining areas...but coverage will be less than Tuesday. As for
high temps...will keep forecast highs a little above model
guidance for most areas. Nearly all guidance shows highs will be 5
to 10 degrees cooler than Tuesday...even though 850 mb temps
actually warm up a degree or two with another day of full sun.
Guidance showed a cool bias on Tuesday...and this appears to be
the case again today. The exception to this bias is in the
Evansville region...where clouds kept temps close to guidance
The main forecast concern for tonight is still frost. A surface
ridge axis will be nearly overhead late tonight. Surface winds
will become nearly calm...which is not the case at this current
hour. The ongoing winds are likely keeping temps several degrees
higher than they will be early Thursday morning. Again prefer the
00z ecmwf mos lows...which are colder than other guidance. The in-
house weighted model...which uses the best performing guidance
over recent model cycles...is in excellent agreement with the
ecmwf. This means that many areas will fall into the mid
30s. Frost is likely in outlying and rural areas...so will
continue the mention of patchy frost in zones/grids and hwo. There
is still not enough confidence in a more widespread frost to issue
a Frost Advisory. The day shift will re-evaluate the need for an
advisory for widespread frost.
On Thursday...an increase in mid and high cloudiness will occur
ahead of a weakening shortwave trough moving southeast from the
Upper Mississippi Valley. These clouds will keep temps on the cool
side despite the wind shift into the southwest. The clouds will
persist through Thursday night. The 00z ecmwf is still the outlier
in generating a little light rain across southwest Indiana and
adjoining counties. Will keep the forecast dry...as nearly all
other guidance indicates.
Friday and Friday night will become mainly clear as a large upper
level ridge builds east from the Plains. Low level winds will become
west to southwest...bringing a warming trend.
.LONG TERM /Saturday through Tuesday/...
Issued at 305 AM CDT Wed Oct 22 2014
Very little to discuss through most of the long term period.
High pressure at the surface and ridging aloft is expected to
produce plenty of sunshine and above normal temperatures through the
rest of the work week, the upcoming weekend, and the first day of
The next chance of precipitation is forecast to make its way into
the far western/northwestern portions of our CWA Next Monday night
with the approach of a weather system coming out of the plains.
Confidence in the evolution of this system is rather low at the
moment as latest long range models not in good agreement.
Around midday Monday the GFS and ECMWF are similar in that they show
the driving mechanism behind this system (a short wave) located over
Colorado. Beyond that their solutions really begin to diverge.
The GFS takes the short wave and associated surface low on a track
from Colorado northeast into the Great Lakes region by midday
Tuesday with a cold front trailing southwest into the southern
plains. During the same 24 hours the ECMWF drives the short wave,
surface low, and front almost due east with all of them moving into
the western/northwestern sections of our CWA.
Tuesday afternoon into Tuesday night the GFS shows the frontal
boundary becoming more parallel to the southwest flow aloft thereby
hanging it up over the northwest half of our CWA. In the same time
frame, the ECMWF promptly moves the system across our CWA, then off
to the east.
Either solution means better chances for precipitation across our
CWA on Tuesday, but obviously the evolution of this system will make
all the difference where placement of QPF is concerned. We will
continue to closely monitor future model runs in hopes that
eventually there will be better agreement.
Issued at 625 AM CDT Wed Oct 22 2014
Some ground fog at kcgi will burn off quickly after sunrise.
Otherwise...no clouds or vsby obstructions are forecast through this
evening. As a surface high pressure ridge passes overhead
tonight...winds will become calm. This will be more conducive for
ground fog than the past few nights. Some ifr conditions are
possible toward sunrise...mainly at the fog prone sites.