Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 112320

Area Forecast Discussion
National Weather Service Paducah KY
620 PM CDT Sun Mar 11 2018

Issued at 555 PM CDT Sun Mar 11 2018

The airport in Evansville (KEVV) has received nearly 2" in the
last hour and a half and moderate to heavy snow is still falling.
This is a bit farther north than expected, and not sure how long
it will continue at that rate. The potential for 4+" over much of
southwest Indiana is increasing. We will continue to monitor
closely for possible upgrade to a Warning, but hopefully the
heavier band will shift south in the next hour or two and we`ll
hold it at or below 4 inches.


.SHORT TERM...(Tonight through Monday)
Issued at 325 PM CDT Sun Mar 11 2018

Well...looks like an interesting time coming up winter weather
wise late today and especially overnight as a well defined
mid/upper low passes just southeast of the forecast area.
Soundings/low and mid level thicknesses all support snow vs rain
from late today (west/north) to this evening and overnight through
the rest of the region. Could be some sleet in between transition.
However, questionable liquid/snow relations, relatively warm
soil temps and surface temps at or just above freezing, make
accumulation forecast and impacts difficult to assess with very
high confidence at this time.

Expecting most impacts on grass/trees and elevated untreated
roadways. However, with it being at night as opposed to the day
time, and if the snow rates increase at times, higher travel
impacts could develop. This could include rapidly reduced
visibilities. Due to the wetness of the expected snow and 10 to
20 mph winds, some tree limbs may come down and local power
disruptions cannot be ruled out.

The Winter Storm Warning headlines for 3-5 inches (locally higher
possible in banding if deformation forms) mainly stretch from
the Purchase area of western KY near Paducah, eastward through
the Pennyrile of KY near Greenville. Locations surrounding this
area are expected to see slightly less amounts in general on the
order of 1 to 3 inches (locally higher if banding occurs).

Believe most of the significant precip will cut off between
midnight and 3 AM as the upper low moves off and we lose our ice
nucleation in the -12 to -20 dendritic growth zone. Depending on
how much snow manages to fall, MOS temps may have a warm bias in
the mid/upper 40s Monday. May stay closer to 40 to lower 40s.

.LONG TERM...(Monday night through Sunday)
Issued at 325 PM CDT Sun Mar 11 2018

Forecast confidence in the long term period starts off higher than
average, then trends down to near average by the end of the week.
Dry weather will prevail through much of the period, with the
potential for wet weather by the end of the week into the weekend.

A highly amplified upper flow pattern will kick off the long term as
a closed upper low over the Great Lakes pivots into the Northeast
through Thursday. Deep north/northwest flow on the west side of the
upper low will result in dry weather and below normal temperatures
through Thursday. The 12Z GFS does hint at the potential for light
showers in the wrap-around moisture Tuesday afternoon and evening
across southwest Indiana. However, will maintain a dry forecast
given for now given the consensus of the NAM, ECMWF, and GEM. Highs
are forecast in the 40s both Tuesday and Wednesday, with readings
moderating close to 60 by Thursday.

The upper pattern is forecast to flatten late in the week as
southerly low level flow develops on the back side of departing high
pressure. This will result in a substantial warming trend by Friday
and the weekend with highs forecast in the 60s on Friday and near 70
both Saturday and Sunday. Upper level energy streaming east from the
Pacific will combine with increasing Gulf moisture to yield a return
chance of showers Friday through Sunday. Models are still not in
good agreement on specifics, but the signal for a wetter pattern
late in the week persists. Depending on the synoptic situation, the
presence of elevated instability warrants at least a slight chance
mention of thunder as well.


Issued at 620 PM CDT Sun Mar 11 2018

Deformation zone snowfall with enhanced snowfall rates have been
lowering visibilities at KEVV the past couple of hours to LIFR/IFR
ceiling and visibility categories. Anticipate this will continue
the next 1-2 hours before shifting to MVFR/VFR categories, as the
deformation zone moves east with time. KOWB should see a similar
reduction for an additional 1-2 hours this evening.

KCGI will see a mix of rain this evening with MVFR conditions,
before returning to VFR conditions around midnight with similar
conditions occurring at KPAH as well.

Most of the lowered visibilities and ceilings can be expected to
shift east-southeast through 08z Monday, along and southeast of
the KPAH-KEVV line into West Kentucky. VFR conditions will
dominate all of the WFO TAF sites after 09z Monday.


IL...Winter Weather Advisory until 4 AM CDT Monday for ILZ075>078-

     Winter Storm Warning until 4 AM CDT Monday for ILZ087-090-091-

MO...Winter Weather Advisory until 4 AM CDT Monday for MOZ076-086-087-

IN...Winter Weather Advisory until 4 AM CDT Monday for INZ081-082-

KY...Winter Weather Advisory until 4 AM CDT Monday for KYZ001-009-012-

     Winter Storm Warning until 4 AM CDT Monday for KYZ002>008-010-



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