169
FXUS64 KMEG 171132
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
632 AM CDT Sat May 17 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 626 AM CDT Sat May 17 2025

- Dry and warm conditions will prevail over the Midsouth today.

- Thunderstorms will return late tonight. There is a Marginal Risk
  for severe thunderstorms over most of the Midsouth. The primary
  risks will be damaging winds and large hail.

- An unsettled weather pattern will continue through Tuesday.
  Cooler and less humid conditions will follow for Wednesday
  through Friday.

&&

.DISCUSSION...
(Today through Friday)
Issued at 632 AM CDT Sat May 17 2025

A dynamic and progressive upper level pattern will prevail over
the U.S. through the middle of next week.

Early morning GOES water vapor imagery showed a closed northern
branch low centered over WI. This feature will lift through the
Great Lakes today, as upstream ridging over the Great Plains edges
into the MS River Valley. Under this ridging, Midsouth temps will
average 3 to 5 degrees above normal. A weak stationary front
will settle over north MS today, separating slightly less humid
air to the north from subtropical air to the south. Out west,
thunderstorms from central TX to OK will develop in tandem with a
shortwave ejecting through the southern plains, out ahead of a
longwave trough over the Great Basin. These storms will lift into
the lower MS River Valley, about the time midlevel heights build
in advance the progressive Great Basin trough. HREF joint
probabilities of surface cape >= 1000 J/kg and 40kt of deep layer
shear is 20% or less, compared to 90% late last night. The main
take away: Tonight`s storms should pose less of a severe risk
relative to Friday night`s storms.

Upper level ridging will prevail Sunday, but 70s dewpoints will
aid in daytime instability and weakening convective inhibition.
By late Sunday afternoon, the ridge axis will lift east, allowing
diffluent southwesterly flow aloft to overspread the Midsouth,
maintaining our convective potential Sunday night.

Monday will see the western U.S. upper low emerge into the Plains.
Ridging aloft and strong onshore flow will allow surface-based
instability to build thruogh the lower MS River Valley Monday
afternoon, prior to a lead shortwave ejecting through Ozarks.
Global models are in reasonable consensus in showing the upper
low lifting through the middle MS River Valley Tuesday evening,
Strong dynamical forcing appears likely, with convection occurring
along and ahead of a progressive surface dryline. At this time, it
appears that Tuesday will holds the highest chance of severe
storms next week.

Following a busy four day period, the Midsouth will finally get a
break from storms, as less humid continental high pressure settles
in under northwest flow aloft.

PWB

&&

.AVIATION...
(12Z TAFS)
Issued at 632 AM CDT Sat May 17 2025

No significant changes to the TAF forecast this period.
Predominantly VFR conditions are expected today with high clouds
and light westerly winds. A few showers and storms could pass
through the area tonight, potentially bringing brief MVFR impacts
to MEM/JBR/MKL towards the end of the period. Confidence is still
not high enough in these hazards to include a TEMPO at this time,
but will be monitored for the 18z TAFs.

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&

$$

PUBLIC FORECAST...PWB
AVIATION...JAB