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fxus63 kpah 230456 
afdpah

Area forecast discussion
National Weather Service Paducah Kentucky
1157 PM CDT sun Sep 22 2019

Update...
issued at 1157 PM CDT sun Sep 22 2019

Updated aviation discussion.

&&

Short term...(tonight through Tuesday night)
issued at 216 PM CDT sun Sep 22 2019

Main forecast challenge in the short term continues to lie with
shower/isolated thunderstorm chances with a frontal passage
tonight. Once again, models seem in decent agreement that the
bulk of the mid level forcing will stay north of the forecast
area. This will leave instability as the main forcing mechanism,
which will be waning during the evening and overnight after the
sun sets. Will keep general quantitative precipitation forecast amounts fairly low, with most
locations at or below 1/4 inch. Should do nothing to temper the
very dry vegetation conditions over much of the region, esp east
of the MS river. Will mention isolated thunder, esp this evening
over portions of southern IL, but again, with instability on the
decrease, am not anticipating anything too strong. Other than a
few left over morning showers Monday in portions of western KY,
expect skies to clear from NW to se behind the front Monday, and
temps should "fall" back to near normal leading into the first
couple days of fall Monday/Tuesday.

Long term...(wednesday through sunday)
issued at 216 PM CDT sun Sep 22 2019

Differential water vapor imagery was depicting the initial stages of
the developing closed low off the Southern California coast and the
sharpening/deepening trough axis along the western U.S. Coast, as
well as the closed low in the western Dakotas this morning.

The GFS ensemble, as well as the European and Canadian guidance
still maintain the general translation/transformation/evolution of
the aforementioned satellite features during the short term period.

The flattened ridge (mainly due to the translation of the northern
U.S./Canadian trough into the upper Midwest will bring the best
chance for rain into the weather forecast office pah forecast area Wednesday into
Thursday.

Although the net effect is the same, the closed low that develops
over California is forecast by the GFS/ECMWF/cmcnh to stall out
further west than expected into the beginning of the extended
forecast period. This low is expected to be lifted and sheared out
as another shortwave trough dives south from western Canada and
moves this low into a faster zonal flow across the northern U.S.
This places the weather forecast office pah forecast area in brief period of southwest
flow on Thursday.

Beyond Thursday, the shifting of the closed low over California into
the northern stream allows a southeast U.S. Ridge to retrograde
westward over the weather forecast office pah forecast area.

From a sensible weather aspect, the weather forecast office pah forecast area will see a
cold frontal passage move through the area late Wednesday night
through Thursday, before stalling out just south of the region.

There is some concern that a better plume of low/middle level
moisture may advect northeast from the Gulf of Mexico by Wednesday,
increasing overall precipitable water and the potential for slightly
more quantitative precipitation forecast than anticipated. May consider a recommendation for locally
heavy rainfall in the hazardous weather outlook for the frontal
passage.

The retrograding ridge should move into the area next weekend,
increasing thermal thickness (and consequently surface temperatures)
by Sunday, as well as inhibiting convection for the weekend.

&&

Aviation...
issued at 1157 PM CDT sun Sep 22 2019

A cold front will sweep through the region during this taf period,
with the wind shift (sustained 12 knots or less) from southwesterly
to northwesterly starting just before daybreak Mon in the northwest
through early afternoon in the southeastern part of the region.
Ahead of this front, scattered showers are expected, lingering in
the Wabash valley until mid morning. MVFR cigs are expected along
this boundary, with some possible brief IFR cigs mainly in southern
Illinois. Rapidly improving conditions are forecast for most of the region
from late morning on, with the pennyrile region of Kentucky following
shortly after.

&&

Pah watches/warnings/advisories...
Illinois...Lake Wind Advisory until 8 PM CDT this evening for ilz075>078-
080>094.

MO...lake Wind Advisory until 8 PM CDT this evening for moz076-086-
087-100-107>112-114.

In...lake Wind Advisory until 8 PM CDT this evening for inz081-082-
085>088.

Kentucky...Lake Wind Advisory until 8 PM CDT this evening for kyz001>022.

&&

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