Flash Flood Warning 6, NWS Memphis, TN

Area Forecast Discussion
National Weather Service Memphis TN
530 AM CST Sat Feb 15 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 518 AM CST Sat Feb 15 2025

 - Life-threatening flash flooding is possible across portions of
   northwest Tennessee through late evening as 4 to 6 inches of
   rain occurs. 2 to 5 inches is possible across the rest of the
   Mid-South. River flooding and flash flooding are possible
   across the entire Mid-South. A Flood Watch is in effect from
   now through 6AM Sunday.

 - Strong to severe thunderstorms are expected for much of the
   area on Saturday afternoon and evening, especially for areas
   along and south of I-40. All hazards (damaging winds, heavy
   rainfall, tornadoes, large hail) are possible. A strong tornado
   or two (EF - 2 or greater) is possible.

 - Well below normal temperatures are favored next week. Long
   range models depict accumulating snow during the middle of next
   week. Arctic air will move into the Mid-South for Wednesday
   through Friday with single digit temperatures possible.

&&

.DISCUSSION...
(Today through Friday)
Issued at 405 AM CST Sat Feb 15 2025

Plenty of convective activity already on radar this morning. The
most recent precipitation observations are pinging at or above 1
inch for along a WSW to ENE line from Jonesboro, AR to Dyersburg,
TN to Paris, TN. Showers and thunderstorms continue to train along
this theta-e axis at this hour, which is coincident with the
moderate and high risk areas for excessive rainfall. The flooding
threat is already ramping up and rainfall totals could approach 3
inches before sunup. A flood advisory has been issued for minor
crest unit streamflow responses.

The latest surface analysis places a 1003mb low near the Texas
Panhandle with a cold front extending southwest into southern
Utah. Another low was analyzed near Houston, TX with an attendant
warm front extending east along the Louisiana Gulf Coast. Aloft, a
deepening positively-tilted longwave trough was located to the
southeast of the Four Corners region with deep southwesterly flow
over the majority of the Mississippi Valley.

The aforementioned trough will rapidly dig south into northern
Mexico and become more neutrally-tilted by 18Z this afternoon.
The Panhandle surface low will take an easterly track and push the
Gulf warm front all the way up to the I-40 corridor during the
same timeframe. The parameter space will quickly become conducive
for all modes of severe weather including damaging winds,
tornadoes (of which a couple could be strong), large hail, and
heavy rainfall. The warm sector will be characterized by moderate
instability, strong deep layer shear, and high levels of low level
helicity. MLCAPE values will range from 1000 to 1500 J/kg with 55
to 60 knots of 0-6 km shear, and 0-1 SRH values in near 350
m2/s2. Point soundings across the warm sector depict large
looping hodographs with low LCLs. There is enough confidence to
begin mentioning the threat of a couple of strong and potentially
long-tracked tornadoes this afternoon and evening. Nearly 40
meter height falls will overspread the increasingly unstable warm
sector between 10AM and 2PM and could spawn a couple of supercells
ahead of an organizing line of convection.

By mid afternoon, the surface low will be located over north-
central Arkansas. HREF guidance is consistent with storm mode
changing from multi-cell clusters to a linear mode between 2 and
4 PM and just to the west of the Mississippi River. Once the line
congeals together, an all hazards threat will unfold as the line
sweeps eastward through late evening. Damaging winds and QLCS
tornadoes are the main threat with large hail and heavy rainfall
as secondary threats. The QLCS should cross the Tennessee River
between 10 PM and midnight. Thereafter, a few trailing showers
will continue through tomorrow morning. Gusty post-frontal
northwest winds will advect in a polar airmass on Sunday. Below
normal temperatures and dry conditions will persist on Monday and
Tuesday.

By Tuesday night, a shortwave will traverse the Southern Plains
and dig ESE into the Lower Mississippi Valley. LREF guidance is
rather consistent with accumulating snow for areas along and north
of I-40. LREF probabilities for 1 inch of snowfall are now 75
percent or greater. Deterministic guidance remains divided on
totals with the ECMWF more bullish than the GFS on snowfall
totals. Nonetheless, there is a strong signal for accumulating
snow at this point.

Thereafter, the polar vortex will unleash a blast of arctic air
upon the Mid-South. NBM guidance suggests that numerous locations
could remain below freezing for 72 hours or more for Wednesday
through Saturday morning. Cold weather products look likely during
the latter part of next week as temperatures plummet into the
single digits. Winter is not over yet.

AC3

&&

.AVIATION...
(12Z TAFS)
Issued at 530 AM CST Sat Feb 15 2025

Warm air advection has allowed shower and thunderstorm activity
to encompass the airspace most of the evening. This trend will
continue as a warm front continues its northern ascent. A squall
line will take aim late this afternoon into early evening with a
cold frontal passage.

Elevated and gusty winds will persist through the day and a
wind shift is expected post frontal. Generally MVFR and IFR CIGs
will prevail through the period. Conditions can deteriorate
further with any thunderstorm activity. An AWW will likely be
needed for KMEM during FROPA. Winds will remain elevated and gusty
post frontal from the NW. MVFR conds will end out the period and
should return to MVFR tomorrow afternoon.

DNM

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Flood Watch through late tonight for ARZ009-018-026>028-035-036-
     048-049-058.

MO...Flood Watch through late tonight for MOZ113-115.

MS...Flood Watch through late tonight for MSZ001>017-020>024.

TN...Flood Watch through late tonight for TNZ001>004-019>022-048>055-
     088>092.

&&

PUBLIC FORECAST...AC3
AVIATION...DNM

Preliminary Local Storm Report
National Weather Service Memphis TN
815 AM CST Sat Feb 15 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0715 AM     Flash Flood      8 ESE Puryear           36.41N 88.20W
02/15/2025                   Henry              TN   Law Enforcement

            Palestine road near Fairgrounds is closed to
            due to flash flooding.

&&

AC3