Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 220819
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
319 AM CDT Fri Aug 22 2014

.SHORT TERM...(Today through Sunday night)
Issued at 300 AM CDT FRI AUG 22 2014

High pressure aloft will continue to strengthen and build across
the lower and mid MS River Valley. Multiple rounds of convection
rotating around the periphery of the high may clip the far eastern
parts of the forecast area from time to time, but should mainly
stay north/east of the area. Will introduce small pops over
portions of sw IN and the Pennyrile region of western KY to cover
this chc tho.

The primary result of the building dome of high pressure aloft
will be the continuation of excessive heat and humidity. Each
afternoon will see the Heat Index average 100 to 105, with
isolated locales potentially exceeding 105 at times. The heat
advisory now in effect will continue thru the short term period
and beyond.

.LONG TERM...(Monday through Thursday)
Issued at 300 AM CDT FRI AUG 22 2014

The main concern in the long term is the duration of the heat wave.
A strong upper ridge will be anchored over the Lower Ohio Valley
early next week. The models begin to diverge Wednesday...when a mid
level trough slides eastward from the Rockies. The timing of this
trough and its associated cold front varies among the models. The
ecmwf and its ensemble mean have been consistently slower and weaker
with this system than the gfs and its ensemble mean.

As far as the daily details...
On Monday...a deep layer high will be centered directly over the
Lower Ohio Valley. The associated subsidence should bring one more
day of abundant sunshine and strong diurnal heating. Could not rule
out a few isolated storms in the heat of the day...but the 00z ecmwf
qpf appears overdone.

On Tuesday...the low level anticyclone /850 mb/ will move east of
the forecast area. The models have consistently been indicating a
surge of moisture as the low level flow turns south to southeast on
the back side of the high. Despite the mid level ridge
overhead...most model guidance develops precip across the Lower Ohio
Valley. This still looks overdone considering the strength of the
mid level ridge...so pops will be kept only in the slight chance
category. Temps may be a few degrees lower than Monday due to
clouds...but forecast peak heat indices are still in the triple
digits.

On Wednesday and Thursday...a cold front will move east/southeast
from the Plains. As stated above...the gfs is faster and stronger
than the ecmwf. Given the high model variability...will go with
chance pops Wednesday into Thursday. Pre-frontal clouds and
convection should lower temps a bit Wednesday. Depending on the
timing of the front...dew points may also come down on Thursday.

&&

.AVIATION...
Issued at 315 AM CDT THU AUG 22 2014

With the exception of IFR/MVFR fog between 08-12Z, dry conditions
with scattered clouds AOA 050 expected as high pressure aloft
builds northward across the TAF sites.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY until 7 PM CDT Tuesday FOR ILZ075>078-080>094.

MO...HEAT ADVISORY until 7 PM CDT Tuesday FOR MOZ076-086-087-100-
     107>112-114.

IN...HEAT ADVISORY until 7 PM CDT Tuesday FOR INZ081-082-085>088.

KY...HEAT ADVISORY until 7 PM CDT Tuesday FOR KYZ001>022.

&&

$$

SHORT TERM...GM
LONG TERM...MY
AVIATION...JP






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