Area Forecast Discussion
Issued by NWS Memphis, TN

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FXUS64 KMEG 011804

Area Forecast Discussion
National Weather Service Memphis TN
104 PM CDT Fri Jul 1 2022


See 18Z aviation discussion below.


.MORNING UPDATE... /issued 1036 AM CDT Fri Jul 1 2022/

A ridge of high pressure remains over the Lower Mississippi
Valley this morning. The ridge is weak enough that a combination
of subtropical moisture and convective temperatures being reached
will result in the development of isolated to scattered showers
and thunderstorms this afternoon with the best coverage occurring
across North Mississippi. Rain chances were adjusted to account
for short term trends as KNQA/KGWX already showing some
development over Central and Northeast Mississippi late this

Updated grids will be available shortly.



.DISCUSSION... /issued 419 AM CDT Fri Jul 1 2022/

Rain chances remain the primary forecast concern, following a
drier than normal June and developing drought conditions over the

We start out today under a broad, east-west subtropical ridge
extending from the southern high plains, through the lower MS
River valley and Southeast. The ridge wasn`t particularly
noteworthy in its strength, at 591dm at 500mb. A plume of 2+ inch
precipitable water (PW) values extended into north MS, downstream
from a weak tropical disturbance along the TX coast. Relative to
Thursday, this moisture plume will make further northward progress
into the Midsouth. However, a weak upper jet streak over north MS
is expected to further weaken through the day, limiting the
already modest deep layer shear and storm organization potential.
Storm coverage may be more dependent on outflow boundary
interactions, with which convection-allowing models (CAMs) often

Similar set-up for Saturday, but with a weak upper trof passing
through the mid-MS River valley. Depending on the coverage of
storms over southeast MO through western KY, a weak boundary may
push into the Midsouth, serving as focus for afternoon storms near
the MO/TN/KY borders.

By Sunday, the upper ridge begins a slow amplification that will
persist through the middle of next week. With PW values remaining
near 2 inches, afternoon showers and thunderstorms will be
possible each day, particularly further east toward the TN River.

The aforementioned upper ridge amplification and persistent mid
70s dewpoints will likely drive heat indices to 105 or higher
Tuesday through Thursday of next week.

Beyond the 7 day forecast, a respite from the heat may be on tap
for the for the following weekend, as medium range models depict
the subtropical height ridge retrograding the 4-corners region.
This would place the Midsouth under northwest flow aloft, possibly
facilitating a weak cold frontal passage. The deterministic GFS
holds on to this northwesterly flow longer than the ECMWF, and the
GFS and ECMWF ensemble means. The consensus suggests that any
moderation in temperatures late next week would likely be brief.




18z TAFs

VFR conditions will prevail through the end of the period at all
sites. A Cu field is spreading across the Mid-South this
afternoon, along with some showers and isolated thunderstorms
across north MS. Carried VCTS at all sites except JBR (have VCSH
at JBR) this afternoon into the early evening as spotty diurnally
driven convection continues to develop across the area. After
those showers die down around 00Z, sporadic Cu lingers and re
develops with more coverage tomorrow afternoon. Winds should
remain under 8kt through the TAF period at all sites and be
generally south to southwesterly.




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