Severe Thunderstorm Warning 166, NWS Jackson, MS

Area Forecast Discussion
National Weather Service Jackson MS
129 PM CDT Sun May 17 2026

...New DISCUSSION, AVIATION...

.KEY MESSAGES...

- A few strong to isolated severe storms are possible today in
  southwest Mississippi, northeast Louisiana and southeast
  Arkansas.

- Heat and humidity more typical of early summer can be expected
  along with increasing thunderstorm chances next week.

&&

.MESOSCALE UPDATE...
Issued at 1157 AM CDT Sun May 17 2026

Rest of today and tonight...

The region remains on the western periphery of subtropical
ridging to the east and mean troughing gradually deepening over
the Intermountain West to Pacific Northwest into mid to late
Sunday. With warm/moist advection (thermal profiles at 850mb in
the mid to upper teens and PWs climbing to 1.5 to 2 inches), an
increase in cloud coverage and some rain chances will be possible
across southwest MS and northeast LA this afternoon into early
evening. Seasonable warmth is expected today, some 4F to 8F above
(highs: 85F to 91F). Thermodynamic parameters remain sufficient
(7.0 to 7.5 deg C mid level lapse rates;25C to 28C vertical
totals; MLCAPE (1000-1500J/kg) and SBCAPE (1500-2500J/kg). There
is some weak deep shear (20 to 35kts) that could support some
strong to isolated severe storms in southwest MS into northeast LA
on Sunday afternoon to evening. In conjunction with Storm
Prediction Center (SPC), added a Marginal in portions of
southwest MS, northeast LA and southeast AR. Hazards are damaging
wind gusts and hail up to quarter size. This has the setup of a
typical diurnal summertime pulse storms/microbursts.

Return flow of low level moisture will bring some low clouds and
visibility reductions, but dense fog is unlikely as HREF dense fog
probabilities remain low. Holding off any mention in the HWO.
Forecast and HWO updates were shipped out earlier. Lows will be
seasonably warm, some 10F to 15F above (65F to 69F east of
I-55 to 70F to 73F along and west of I-55). /DC/

&&

.DISCUSSION...
Issued at 128 PM CDT Sun May 17 2026

Through the work week (Monday through Friday)...

Cold core low, developing over the Four Corners, will eject into
the northern Plains to Great Lakes and into Canada and Hudson Bay
region. Persistent seasonable warmth (4F to 8F above and highs in
86F to 91F) and moisture (forecasts of 1.5 to 2 inches and GOES
East satellite derived PWs generally similar) will be the norm.
Summertime pattern is on tap, with scattered rain and storm
currently developing and later coverage (20 to 50 percent) and
increased heat and humidity. With some steep lapse rates (vertical
totals near 27C to 29C), some strong to isolated severe cannot be
ruled out into early to mid week (as early as Monday but most
likely Tuesday into Wednesday). There is an ongoing Marginal
outlook for northwest to northern areas in the Hwy 82 corridor
Tuesday afternoon to evening. There is support of diurnal
microburst potential and pulse severe but deep flow/bulk shear
will be light and variable and storm organization mostly driven by
storms that are favorably oriented low level bulk shear.

As a stronger wave swings into the Great Lakes and surface low
ejects into eastern Canada (995mb to 1000mb), front will shift
south southeast towards the Gulf states. A southern stream
shortwave will enhance upper diffluence, increasing ascent and
moisture advection. This will drive higher coverage of rain and
storms (45 to 90 percent Wednesday and 55 to 75 percent on
Thursday).High temperatures will be seasonable, with lows less
seasonable, falling from 8F to 12F above (upper 60s to low 70s
west) to 4F to 8F above (mid to upper 60s). With less seasonable
temperatures, humidity and lapse rates, some stronger storms
are likely and marginally severe storms remain possible. Mid to
deep layer bulk shear will remain sufficient (around 30kts), with
low level shear around 15-25kts. This will keep potential
marginally severe concerns through the remainder of the work
week (Wednesday through Friday). Rain totals for the week will be
around a couple of inches (1 to 3 inches), which will help lessen
some long term drought concerns. /DC/

&&

.AVIATION...
(18Z TAFS)
Issued at 1256 PM CDT Sun May 17 2026

VFR conditions will prevail until after 08Z when MVFR/IFR CIGs
likely develop across southern sites, persisting until after 14Z.
Winds will generally be out of the south 5-10 kts with gusts 15-20
kts possible after 16Z Monday. Intermittent TSRA/SHRA will be
possible at HEZ and from 22z through 01Z.  /86/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       70  88  72  88 /  10  10   0  50
Meridian      65  88  69  89 /   0  20   0  10
Vicksburg     71  89  72  89 /  10  20  10  30
Hattiesburg   67  88  70  89 /   0  30   0  20
Natchez       73  89  73  90 /  10  20  10  40
Greenville    72  90  73  91 /  20  10  20  30
Greenwood     72  89  73  90 /  10  10  10  30

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&

DC/LP

Special Weather Statement
National Weather Service Jackson MS
500 PM CDT Sun May 17 2026

MSZ056-172300-
Smith MS-
500 PM CDT Sun May 17 2026

...STRONG THUNDERSTORMS WILL IMPACT NORTHERN SMITH COUNTY THROUGH 600
PM CDT...

At 459 PM CDT, Doppler radar was tracking a cluster of strong
thunderstorms near Raleigh, moving northeast at 20 mph.

HAZARD...Wind gusts up to 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

This strong thunderstorm will be near...
  Raleigh and Burns around 505 PM CDT.
  Pineville around 515 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3190 8965 3201 8965 3205 8966 3205 8970
      3222 8959 3222 8933 3198 8932
TIME...MOT...LOC 2159Z 219DEG 18KT 3203 8958

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

SAS

Special Weather Statement
National Weather Service Jackson MS
546 PM CDT Sun May 17 2026

MSZ048-049-054-055-172345-
Copiah MS-Hinds MS-Rankin MS-Simpson MS-
546 PM CDT Sun May 17 2026

...STRONG THUNDERSTORMS WILL IMPACT SOUTHWESTERN RANKIN...
NORTHWESTERN SIMPSON...SOUTHEASTERN HINDS AND NORTHEASTERN COPIAH
COUNTIES THROUGH 645 PM CDT...

At 546 PM CDT, Doppler radar was tracking a cluster of strong
thunderstorms near Crystal Springs, moving northeast at 20 mph.

HAZARD...Wind gusts up to 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

This strong thunderstorm will be near...
  Terry and Dry Grove around 550 PM CDT.
  Jackson around 555 PM CDT.
  Byram around 600 PM CDT.
  Whites around 605 PM CDT.
  Richland around 620 PM CDT.
  Florence around 625 PM CDT.
  Monterey around 640 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3199 9058 3226 9045 3225 9019 3217 8999
      3203 9014 3190 9032
TIME...MOT...LOC 2246Z 217DEG 17KT 3203 9039

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

SAS