Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 172326
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
526 PM CST Fri Nov 17 2017

.UPDATE...
Issued at 523 PM CST Fri Nov 17 2017

Updated Aviation discussion for 00Z TAF Issuance.

&&

.SHORT TERM...(Tonight through Sunday night)
Issued at 232 PM CST Fri Nov 17 2017

Main forecast challenges lie with the potential for strong winds
and the risk for thunderstorms with a cold frontal passage on
Saturday.

Southerly flow will be increasing during the night as the pressure
gradient tightens across the region. Winds of 15 to 25 MPH will be
common place by Saturday morning, with higher gusts possible. This
strong southerly flow will produce slowly rising temps and dew
points as we head through the night. There may be some sct warm
advection showers later tonight, esp in southern IL and se MO,
but many locations will be mostly rainfree until the
aforementioned cold front approaches and moves through on
Saturday.

Wind profiles will be quite strong with this system, with winds to
near 50 MPH about 2000 ft off the deck. Warm air advection in the
low-levels will further be augmented by a 50-60 kt low-level jet.
However, the mid/upper trof looks to be coming through with a
positive tilt, and instabilities look quite marginal with MUCAPES
likely to stay at or below 700 J/KG for the most part. Still,
this time of year in a high shear/kinematic environment, we do not
need too much CAPE to get some severe cells with damaging wind
gusts on a developing squall line. So we will need to keep an eye
on this possibility. SPC still maintains a marginal risk for
severe storms Saturday.

Surface gradient winds ahead of and especially behind the front
Saturday will likely be running in the 20-30 MPH range with gusts
over 40 MPH at times. Therefore, have issued a wind advisory area
wide for Saturday into early Saturday night.

Drier and much cooler air will blow in on the heels of the front
Sunday and Sunday night. Highs will struggle into the 40s Sunday
with lows Sunday night in the mid and upper 20s.

.LONG TERM...(Monday through Friday)
Issued at 232 PM CST Fri Nov 17 2017

Dry and seasonable forecast remains in place from Monday through
Friday. At this point, still have higher confidence (60-70%) that
weather will remain dry through the forecast period.

Each of the deterministic model runs continue to have varying
spatial (location) solutions on the evolution of the shortwave that
dives from the Pacific Northwest on Monday, southeastward through
the Central and Southern Plains, and into the Southeast
U.S./northern Gulf of Mexico by Wednesday morning. Regardless of
the solution, any residence time for deep layer moisture is almost
non-existent. This would continue to support a dry cold frontal
passage on Tuesday afternoon.

Another cold front is advertised to dive down in northwest flow late
next Friday night into Saturday the 12z Friday ECMWF/Canadian/GFS
12z deterministic model runs. Deeper layer moisture will be evident
closer to the Tri-State area (Southeast Illinois, Southwest Indiana,
Northwest Kentucky), but timing is variable enough that any chance
for precipitation will not even be mentioned in this package.

At least within the extended forecast period, maximum temperatures
will remain with five degrees of normal highs for this time of year.
Lows will range from 5 to 10 degrees below normal, with the greatest
departure expected late Tuesday night, then again into next weekend.

&&

.AVIATION...
Issued at 523 PM CST Fri Nov 17 2017

Mid level cigs will drop tonight/tmrw morning, ahead of a cold
front which will make its passage/presence felt around midday-
early pm hours. MVFR restrictions mainly to cigs will drop to near
IFR cigs/vsbys in heavier showers upon the front`s passage, with
some improvement back to mid or upper range MVFR by the end of the
day, with perhaps western sites (KCGI/KPAH) returning to VFR or
low end VFR cigs by then. Winds will strengthen and become gustier
with time, out of the south til fropa, then shift to the northwest
and maintaining their strength/gusts thru the duration of the
planning period.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Wind Advisory from 6 AM to 9 PM CST Saturday for ILZ075>078-
     080>094.

MO...Wind Advisory from 6 AM to 9 PM CST Saturday for MOZ076-086-087-
     100-107>112-114.

IN...Wind Advisory from 6 AM to 9 PM CST Saturday for INZ081-082-
     085>088.

KY...Wind Advisory from 6 AM to 9 PM CST Saturday for KYZ001>022.

&&

$$


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