Forecast Discussion

FXUS64 KMEG 161811

Area Forecast Discussion
National Weather Service Memphis TN
111 PM CDT Thu Aug 16 2018


Updated for aviation discussion


.PREV DISCUSSION... /issued 1149 AM CDT Thu Aug 16 2018/


Remnants from the line of convection that brought heavy rain to
portions of Northeast Arkansas and the Missouri Bootheel early
this morning continues to push east across West Tennessee.
Locations near the Tennessee River and Northeast Mississippi will
be impacted this afternoon. In addition, can`t rule out some
redevelopment along old outflow boundaries that are located across
Northeast Arkansas and West Tennessee. Have adjusted POPS
accordingly and lowered highs across portions of West Tennessee
due to the ongoing convection. Update will be out shortly.


DISCUSSION... /issued 710 AM CDT Thu Aug 16 2018/

MCS across the northern half of the CWA will slowly erode this
morning...with convection expected to become isolated by 10
am...with skies becoming partly sunny soon after. Rainfall amounts
of upwards of 7 inches has fallen...with rates 1 to 2 inches per
hour remaining persistent along I-55 over the next hour. Have
adjusted morning PoPs to capture the forecasted trend.


PREV DISCUSSION... /issued 304 AM CDT Thu Aug 16 2018/

Moderate to heavy precipitation is going on across the northern
counties...where storms are likely to train for the next few hours.
Three hourly rainfall amounts already approaching 3 inches across
portions of Craighead and Greene Counties. An additional 1 to 2
inches would overfill ditches and cause minor street flooding.
Mesoscale Precipitation Discussion indicates a slight chance for
flash flooding today. Farther south only occasional light
sprinkles producing a trace have been tracking through the region.
Current temperatures ranging from the mid 70s where precipitation
is a few readings in the lows 80s in north
Mississippi. Winds have been south at 5 to 10mph...with gusts
approaching 30 mph in heavier convection.

For today through Saturday...models are in good agreement that the
Midsouth will remain unsettled with multiple periods of clouds and
precipitation. This due to an active northwesterly upper flow. IR
satellite showing current convection in the northern counties
anchored in the base of a passing trough...some breaks are
currently seen with this an extensive flood threat
is not anticipated. CAMs show cloud tops warming after sunrise as
well. Activity will likely re-fire in the northeastern counties
after 12 pm...and again in the western counties this evening.
Coverage will become more isolated late tonight.

A stronger closed low sinking southeast over Nebraska will
quickly begin affecting the region tomorrow through Saturday.
This disturbance is expected to bring better rain chances over the
central and southern Midsouth counties where rain is more
welcome. Pockets of rainfall amounts of 5+ inches over the next
three days can`t be ruled out in the north...with the south
generally in the 1-3 inch range. The region is under a marginal
risk for severe storms today and tomorrow as well...with severe
indices indicating the potential across the southern counties
on Saturday. Plan on including both an isolated severe storm and
localized flash flood wording in the morning hazardous weather
outlook. Temperatures could be above seasonal normals today in the
I-40 corridor and points south where more sun will be
fact the NAM MOS shows a high of 97F in Memphis with heat indices
topping 105F. Believe that is a bit to much...leaning closer to
the GFS MOS of 90F. Over the north thicker cloud cover and
rainfall will keep highs in the mid and upper 80s. Slightly cooler
readings over the central and south for Friday and Saturday.

Sunday through midweek...a third shortwave will track southeast
from the northern Rockies...affecting more of the Midsouth on
Monday then any other day. Rain chances will subside across the
north on Sunday...with scattered coverage in the south.
Temperatures near normal. Starting Sunday night the next complex
of precipitation will slide east from the Ozarks and persist
into Monday night as a cold front approaches the area. A drier
airmass will slowly infiltrate the Midsouth on Tuesday suppressing
convection to the southern counties. Wednesday and Thursday of
next week appear to be dry and pleasantly mild.




MCS that moved across northern sections of the Mid-South has just
about dissipated. Should see some additional activity this
afternoon with best chances along and south of the outflow
boundary from this morning`s convection including KMEM/KMKL/KTUP.
Expect a lull this evening then another MCS will move into the
Mid-South from the northwest. Timing is variable on all the CAMs
but for now going with about 08z at KJBR and 10z at KMKL/KMEM.
Not sure if it will hold together all the way to KTUP. Outside of
TSRAs expect mainly VFR conds. Winds will be SSW around 10 kts
during the afternoon diminishing to 5 kts overnight.