Forecast Discussion

FXUS64 KMEG 191137

Area Forecast Discussion
National Weather Service Memphis TN
637 AM CDT Mon Aug 19 2019


Update for 12Z TAF issuance.


.PREV DISCUSSION... /issued 350 AM CDT Mon Aug 19 2019/


Currently...Upper level high pressure is centered over Texas with
surface high pressure along the Atlantic seaboard. A few clouds
cover the TN River valley and NE MS this morning otrw clear skies
persist along with light winds. Temps range from the lower to mid
70s. Surface dewpoints have climbed a bit more in the last 24 hrs
and are mainly in the lower 70s.

Today through Wednesday...Upper level high pressure will build
over the region through mid week. Expect hot and humid conditions
with highs in the mid 90s and afternoon heat index values
reaching or exceeding 105 degrees. A heat advisory will be issued
through Wednesday evening. Little relief expected at night with
overnight lows in the mid to upper 70s. Isolated thunderstorms
will develop this afternoon and quickly dissipate with loss of
heating this evening. A shortwave moving over the upper ridge and
into the Plains overnight will likely trigger an MCS that all the
CAMs are forecasting to move south into northern sections of the
Mid-South late Tuesday afternoon. Since all the CAMs are in lock
step and the synoptic models support this scenario have increased
pops to likely across NE AR...the MO Bootheel and NW TN Tuesday
afternoon and will introduce a slight chance pop Tuesday evening
to cover any remnants. A few strong to severe storms are possible
across northern sections with damaging wind the main threat. The
upper ridge start to weaken slightly on Wednesday but not before
another hot and humid day. Expect isolated to scattered
thunderstorms by the afternoon.

Thursday and Friday...An mid level trough will push through the
Great Lakes and send a cold front toward the region. Upper level
heights will also weaken with weak troughing developing aloft. As
a result rain chances will be on the increase during this period.
Temps will be slightly cooler due to clouds and precip.

Saturday and Sunday...By Saturday morning the surface front
should bisect the area. The ECMWF is more aggressive with moving
the front south during the weekend while the GFS lifts it back
north more quickly. The ECMWF version could bring some lower
dewpoints well south into the area. Either way weak upper level
ridging will try to rebuild into the area so precip chances should
diminish. High temps will be in the upper 80s to around 90.



.AVIATION...12Z TAF Issuance

Mainly VFR conditions expected this TAF cycle. Scattered
SHRA/TSRA expected to develop after 20Z with greatest coverage
south of the I-40 corridor. Will continue with VCSH at
KMEM/KMKL/KJBR in the mid afternoon-early evening hours. Will go
with VCTS at KTUP given higher expected coverage. Low temp-
dewpoint spreads so will include tempo 4-5 BR toward 12Z Tuesday.
Winds generally southerly at less than 7 knots.



AR...Heat Advisory from 11 AM this morning to 8 PM CDT Wednesday for
     Clay-Craighead-Crittenden-Cross-Greene-Lee AR-Mississippi-
     Phillips-Poinsett-St. Francis.

MO...Heat Advisory from 11 AM this morning to 8 PM CDT Wednesday for

MS...Heat Advisory from 11 AM this morning to 8 PM CDT Wednesday for
     Alcorn-Benton MS-Calhoun-Chickasaw-Coahoma-DeSoto-Itawamba-
     Lafayette-Lee MS-Marshall-Monroe-Panola-Pontotoc-Prentiss-

TN...Heat Advisory from 11 AM this morning to 8 PM CDT Wednesday for
     Benton TN-Carroll-Chester-Crockett-Decatur-Dyer-Fayette-