Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 231154
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
652 AM CDT Thu Oct 23 2014
Updated aviation section for 12z tafs
.SHORT TERM...(Today through Saturday night)
Issued at 335 AM CDT Thu Oct 23 2014
Main concerns early this morning are patchy frost and fog. The
coldest temps so far have been in the mid 30s across parts of
southern Illinois...from the kmvn/kmdh corridor east to Harrisburg.
Temps elsewhere were still in the 39 to 44 degree range at 08z. For
most of our region...it appears frost coverage will be patchy this
morning. As far as the fog...there has not been any dense fog so
far...but there will likely be some dense fog patches around
sunrise. Added mention of patchy fog to zones/grids for early this
Satellite indicates mid and high clouds over western Missouri and
Arkansas are making steady eastward progress. This cloudiness is
associated with a weakening 500 mb shortwave trough that will reach
the Mississippi River this afternoon. Very dry air in the low levels
/associated with the surface high over our region/ will negate any
mention of precip today. Model high temp guidance has been running a
little too cool on recent days...so will keep forecast highs a
degree or two above mos.
During the night tonight...another shortwave trough will move
quickly southeast across the Great Lakes into the Ohio Valley. This
system will keep some mid and high cloudiness over our region. Temps
will be milder due to the clouds and light southwest winds behind
the retreating surface ridge.
On Friday...light southwest winds and clearing skies should combine
to push high temps to at least 70 degrees in much of our region. The
relatively mild conditions will continue Friday night.
On Saturday...model guidance is in good agreement that a weak
surface cold front will move southeast across our region. The nam is
the most aggressive with moisture return ahead of this front. The
nam indicates some light precip will accompany the front...but it
remains an outlier. Will keep the forecast dry...but a band of low
cloudiness is likely to precede or accompany the front. Given the
warm start to the day and increasing afternoon sunshine...guidance
highs in the mid to upper 70s look reasonable. Cooler and drier
conditions will arrive behind the front Saturday night.
.LONG TERM...(Sunday through Wednesday)
Issued at 335 AM CDT Thu Oct 23 2014
The long term is based on a blend of the latest and previous
ensemble means from the GFS and ECMWF. This should minimize any
model errors and discrepancies in handling more specific features
within broad progressive w/e flow across the conus. Moderate run to
run issues exist with the operational runs of the GFS and ECMWF.
Sunday and Monday should be dry with above normal temperatures. SW
flow aloft will develop, while a warm front lifts north of the
region. By 18z Monday, a strong high should cover the Atlantic
states and coast with low pressure over the upper Midwest, and a
trailing front into the southern high plains. No precip with a very
dry airmass over the region.
Tuesday, energy aloft will move out of the nations mid section,
accompanied by the arrival of a modest cold front. Think most of
Monday night will be dry. However chances for showers increase
substantially Tuesday. As the energy moves NE, with the surface
low moving north of the Great Lakes, the movement of the boundary
and progression of forcing and moisture should slow. Carried higher
PoPs into Tuesday night, then lowered them from NW to SE Wednesday,
dry for now Wednesday night. Have added a thunder mention as
instability parameters suggest the possibility.
Issued at 652 AM CDT Thu Oct 23 2014
Shallow ground fog will burn off quickly after sunrise. Mid and high
clouds will increase later this morning and this afternoon...but
cigs will be above 10k feet. Winds will be light as surface high
pressure holds sway through this evening. The potential for fog
appears lower tonight due to mid and high cloudiness...but some
shallow ground fog is possible if clouds become scattered.