Severe Thunderstorm Warning 253, NWS Jackson, MS

Area Forecast Discussion
National Weather Service Jackson MS
842 PM CDT Sun Aug 18 2024

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE...
Issued at 842 PM CDT Sun Aug 18 2024

The severe weather threat continues across western/central
portions of the forecast area this evening. A small convective
system associated with a strong moist/instability axis ahead of a
southward moving cold front is pushing quickly southward along
the MS River. While there has been a slight downward trend in
updraft intensity, large downdraft CAPE (e.g., 1726 j/kg per 00z
JAN raob) preceding the system will support continued severe wind
potential for next few hours. Otherwise, it still looks like
we'll maintain some overnight convective rainfall potential over
western portions of the area with continued theta-e advection on
periphery of drier air push as previously discussed, but this
activity is likely to not be sfc-based and overly instense in the
wake of the evening system. /EC/

&&

.DISCUSSION...
Issued at 131 PM CDT Sun Aug 18 2024

Through tonight...

We have a bit of an unusual set up today with a long wave trough
evident over the east CONUS, while a strong midlevel high is parked
over the southern plains. This will bring a combo of heat and severe
hazards today and tonight.

Heat: Temperatures aloft associated with an 850 thermal axis will
support very warm surface temperatures this afternoon with highs
peaking in the upper 90s and low 100s across the area, as NW flow
favors deep mixing. While dewpoints do mix down into the low 70s and
upper 60s, The higher temperatures should compensate. Resulting
heat indices will be in the 105 to 115 range and support the
continuation of an excessive heat warning for much of the area
until 8 PM tonight. Lower dewpoints due to mixing should keep heat
indices closer to the 105 to 110 range for northeastern areas. As
such, this area is under heat advisory until 8 PM.

Severe: It addition to heat, an anomalous jet max around 40 to 50kts
will overspread this very warm unstable airmass with strong flow for
this time of year. A series of shortwaves rounding the base of the
upper trough will help to initiate storm development across central
Arkansas later this afternoon, propagating SSE around the eastern
periphery of the midlevel high. An 850 theta e max should help to
maintain organized complexes, especially along the Mississippi
River. With moisture holding in this zone, the strongly sheared and
unstable environment will be very favorable for cold pool
maintenance and drive a severe, perhaps significant, wind threat.
Damaging winds could even be associated with strong outflow
boundaries well ahead of storms, especially later in the evening. A
slight risk is highlighted for much of the area to account for this.
A less favorable environment in the northeast limits confidence in
severity and longevity and so a marginal has been delineated
there. Storms should continue to progress SSE until late this
evening into tonight. There are a few limiting factors, with very
warm temps aloft and somewhat dry conditions. However, the
thinking is the favorable conditions will be able to overcome the
limitations. /SAS/

Monday Morning through Thursday...

Relief from the staggering heat is on the way! By Monday morning a
welcome regime change will begin to take shape, allowing for
northerly to easterly winds throughout the period. This wind shift,
will be caused by a ridge/surface high building in from Texas and
traversing from the Oklahoma Panhandle to southern Missouri. In
general, the weather for the week can be characterized by drier,
cooler conditions, with highs not exceeding 95F and relative
humidities not exceeding 40% during the day. Overnight lows during
the week will be below 70F, bottoming out in the low 60s Thursday
morning before slowly rebounding towards 70F as the week comes to a
close. In keeping with the theme of drier conditions, we will not
see PWATs climb above 1.2 throughout the period either, allowing for
virtually no chance for showers/thunderstorms.

Fire weather may be an area of concern throughout the week, with our
low relative humidities, winds, and generally favorable
conditions. At this time we will continue to monitor the threat
closely but see no need to signal a heightened threat just yet.

Friday through next Sunday...

There will be chances for afternoon showers as return flow
reinstates itself on the back end of the aforementioned high and a
cut-off low/trough comes in from the Gulf, providing increased
levels of moisture and lift across southern reaches of the
forecast area. We will continue to keep a close eye on this
weekend to hone the coverage, intensity, and chances for
convective activity. /OAJ/DC/

&&

.AVIATION...
(00Z TAFS)
Issued at 706 PM CDT Sun Aug 18 2024

Primary concerns this forecast period will be associated with a
convective system pushing southward across western portions of
the area this evening, especially along/west of the GLH/JAN
corridor, and a convective threat may continue into the HEZ area
overnight into early Monday morning. Otherwise, expect VFR
conditions to prevail for the most part as drier air pushes in
for the remainder of the forecast. /EC/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       75  93  70  92 /  60  20  10   0
Meridian      72  94  67  92 /  40   0   0   0
Vicksburg     74  91  69  92 /  60  30  10   0
Hattiesburg   76  96  71  94 /  50  10   0   0
Natchez       74  91  70  92 /  60  30  10  10
Greenville    73  90  67  89 /  70  30  10   0
Greenwood     72  93  67  90 /  50  10   0   0

&&

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

&&

SAS20/OAJ/EC

Preliminary Local Storm Report
National Weather Service Jackson MS
811 PM CDT Sun Aug 18 2024

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

0751 PM     Tstm Wnd Gst     2 NW Schlater           33.66N 90.37W
08/18/2024  M59 MPH          Leflore            MS   Mesonet

            Recorded by private weather station near
            Schlater.

&&

DL

Preliminary Local Storm Report
National Weather Service Jackson MS
813 PM CDT Sun Aug 18 2024

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

0746 PM     Tstm Wnd Gst     1 ESE Burdett           33.34N 90.89W
08/18/2024  M55 MPH          Washington         MS   Mesonet

            Measured by private weather station near
            Burdett.

&&

DL

Preliminary Local Storm Report
National Weather Service Jackson MS
824 PM CDT Sun Aug 18 2024

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

0758 PM     Tstm Wnd Dmg     1 N Moorhead            33.46N 90.51W
08/18/2024                   Sunflower          MS   Law Enforcement

            Law enforcement reported multiple trees and
            powerlines down across Sunflower County.

&&

CR

Preliminary Local Storm Report
National Weather Service Jackson MS
843 PM CDT Sun Aug 18 2024

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

0740 PM     Tstm Wnd Dmg     1 S Hamburg             33.22N 91.80W
08/18/2024                   Ashley             AR   Law Enforcement

            Law enforcement reported a roof blown off of
            a business on Main St near Hamburg AR.

&&

CR

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