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Area forecast discussion 
National Weather Service Memphis Tennessee
742 PM CDT Tuesday Jul 28 2015

Update...evening update.

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Discussion...
temperatures are finally cooling off slightly although overnight
lows are not expected to fall much below 80 degrees across the
warmest portions of the midsouth. Heat indices remain above 100
degrees acros the region...and will likely remain well into the
90s through midnight. The exception may be in west Tennessee near
the Tennessee River. A line of thunderstorms is approaching...and
it looks more likely than not that they will reach our
noerheastern countise within the next several hours. As a
result...this area will likley cool into the low 70s. Adjusted
probability of precipitation and temperatures accordingly. Tomorrow looks hot again...but
rain chances will increase. Relief is in sight area wide after
midweek.

30

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Previous discussion... /issued 616 PM CDT Tuesday Jul 28 2015/

Currently...595dm upper ridge is centered just west of the
midsouth. Very hot and humid conditions prevail across the region.
Temperatures are climbing into the middle and upper 90s with dewpoints in
the upper 70s...even near 80 across the Delta. This is producing
heat index values over 110 across western parts of the mid-south.
Upgraded the heat advisory to an excessive heat warning across
eastern Arkansas...northwest Mississippi and extreme west
Tennessee including the Memphis area through Wednesday. A few
showers and thunderstorms have popped up along the Tennessee
River.

Tonight...very warm overnight with little relief from the heat.
Isolated showers/thunderstorms along the Tennessee River will
dissipate with loss of heating this evening. Will keep a small pop
along the Tennessee River overnight since models do point to a
weak upper level disturbance moving south into middle Tennessee
and this feature could spark a few showers and thunderstorms
overnight.

Wednesday...the upper ridge actually noses into the area a little
more and 925 mb temperatures increase slightly. Meanwhile the approaching
cold front should serve to pool dewpoints which are already very
high across the Delta. All these factors point to a very hot and
humid day with heat index values exceeding 110 over a good deal of
the area. The excessive heat warning may need to be expanded
further even east. Since the upper ridge is still quite strong
Wednesday elected to cut probability of precipitation everywhere except northeast
Mississippi. Kept probability of precipitation a little higher there as a weak upper level
disturbance pushes into Alabama during the day. This feature could
increase coverage of showers/thunderstorms across northeast
Mississippi Wednesday afternoon.

Wednesday night and Thursday...a cold front will push through the
area with little upper support. As a result precipitation chances are not
that impressive. More importantly though the front will break
this streak of oppressive heat. Drier and cooler air will begin
working in behind the front. Before that happens however...there
is a possibility that a few locations in north Mississippi could
hit heat advisory criteria Thursday afternoon. Will need to
watch.

Friday through early next week...surface high pressure will build
in with weak northwest flow aloft. Highs will be around 90 Friday
and then slowly climb each day back into the middle 90s early next
week. Fortunately the airmass will be much drier with dewpoints
remaining in the 60s which will feel much more pleasant.

Sjm

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Aviation...
00z taf cycle

Patchy fog may develop again at mkl late tonight producing
temporary MVFR/IFR conditions. Otherwise...VFR conditions expected
to prevail at sites for most of the period. Thunderstorms in the vicinity possible at sites
after 29/12z as upper level ridge begins to weaken slightly and a
weak cold front enters the lower Mississippi Valley.

Cjc

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Meg watches/warnings/advisories...
Arkansas...excessive heat warning until 8 PM CDT Wednesday for Clay-
Craighead-Crittenden-cross-Greene-Lawrence-Lee Arkansas-
Mississippi-Phillips-Poinsett-Randolph-St. Francis.

MO...excessive heat warning until 8 PM CDT Wednesday for Dunklin-
Pemiscot.

MS...excessive heat warning until 8 PM CDT Wednesday for Coahoma-
DeSoto-Marshall-Panola-Quitman-Tallahatchie-Tate-Tunica.

Heat advisory until 8 PM CDT Wednesday for Alcorn-Benton MS-
Calhoun-Chickasaw-Itawamba-Lafayette-Lee MS-Monroe-Pontotoc-
Prentiss-Tippah-Tishomingo-Union-Yalobusha.

Tennessee...excessive heat warning until 8 PM CDT Wednesday for Dyer-Fayette-
Lake-Lauderdale-Obion-Shelby-Tipton.

Heat advisory until 8 PM CDT Wednesday for Benton Tennessee-Carroll-
Chester-Crockett-Decatur-Gibson-Hardeman-Hardin-Haywood-
Henderson-Henry-Madison-McNairy-Weakley.

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