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fxus63 kpah 051123 
afdpah

Area forecast discussion
National Weather Service Paducah Kentucky
523 am CST Thu Dec 5 2019

Update...
issued at 514 am CST Thu Dec 5 2019

Updated aviation discussion for the 12z tafs.

&&

Short term...(today through friday)
issued at 232 am CST Thu Dec 5 2019

The combination of clear skies and calm winds with the high
pressure system over the quad state region is resulting in chilly
conditions overnight with much of southern Illinois below freezing.
A shortwave low pressure system is forming east of The Rockies
and will dip into Oklahoma late today. Ahead of this system
southerly winds will bring another day with temperatures in the
upper 50s. Cloud cover and dew points will increase through
Thursday ahead of the system.

The shortwave low will move into the deep south Friday limiting
precipitation for the quad state. In southeast Missouri,
showers may begin Thursday evening, while showers will spread
over the rest of the quad state overnight. Lows Thursday night
will be warmer with temperatures in the low 40s. Precipitation
will be mostly light on and off showers into Friday, exiting to
the east by Friday afternoon. Between Thursday evening and Friday
afternoon precipitation totals will generally be low, on the
order of a tenth of an inch. Behind this system more northerly
flow will bring cooler air.

Long term...(friday night through wednesday)
issued at 232 am CST Thu Dec 5 2019

Overall operational models run to run continuity is relatively poor,
with a wide range of possibilities, mainly from Sunday night on.
They are struggling with the eastern Pacific low, and how it will
eventually interact with a deep long wave trof covering much of
Canada and north central U.S. We prefer to lean heavily on the
ensemble mean solutions for now, with substantial weighting given to
the nbm, at least until the models can lock in.

High pressure will be over the area at the beginning of the period.
Dry weather as a result Friday night through Saturday night. Return
flow sets up for Sunday through Sunday night. Given the warm, moist
advection forecast into the region, expect a good chance of light
rains and possibly drizzle, highest chances central and east
sections of our area.

Monday, a surface front is forecast to move across the area during
the afternoon and evening. Rains will accompany the front.
Instability still looks to be lacking, so no thunder mention at this
time. Monday night into Tuesday is when the model agreement and run
to run continuity fall apart. The 12z GFS run was slower moving
precip through and then out of the area. The 12z European model (ecmwf) was much
quicker. The 00z runs are opposite, GFS now faster, European model (ecmwf) slower.
The CMC was basically ignored. The nbm offers a middle ground
approach with respect to pops. Will taper off pops Monday night into
Tuesday morning. Cannot rule out left over rains mixing with or
changing to snow briefly before ending. It's simply way too soon to
say with any confidence how this will play out. Wednesday should be
dry with high pressure returning.

Temperatures will be near to above normal Saturday through Monday.
Winter will return with colder temperatures Tuesday through
Wednesday.

&&

Aviation...
issued at 514 am CST Thu Dec 5 2019

Skies remain clear over most of the quad state region with only a
few high clouds heading into the morning. Through the course of
the day Thursday cloud heights will lower and cloud cover will
increase, becoming overcast by the evening. Shower activity is
delayed slightly compared to the previous timing estimate with
showers moving in Thursday night. Conditions will likely remain
VFR for the 24-hour period, though just beyond that cloud heights
are projected to lower to MVFR heights.

&&

Pah watches/warnings/advisories...
Illinois...none.
MO...none.
In...none.
Kentucky...none.
&&

$$

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