Severe Thunderstorm Warning 240, NWS Jackson, MS

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
1019 AM CDT Mon Jun 17 2019

.UPDATE...
Updated for morning discussion.

&&

.DISCUSSION...
On the charts this morning, a relatively weak surface trough
extends from central AR through NW Louisiana in association with a
mid/upper shortwave that is moving eastward into the Mid South
today. An MCS is advancing S/SEward into the NW Gulf, the
northern extent of which reaches into south central LA. The
modified 12z KJAN RAOB depicts a moist and rather unstable airmass
over the area. Though deep layer shear is rather modest, the
surface-3 km bulk shear magnitude was much more respectable.

The most likely areas for initial convective initiation will be
with convergence along any outflow or differential heating
boundary on the northern edge of the MCS (around Central LA or
Southwest MS) and along a broader zone of weak surface
convergence extending northward from the MCS through roughly along
the MS River. Along with the local microburst checklist
indicating some wet microburst potential, the aforementioned
corridor of 20-30 kt 0-3 km bulk shear will promote some damaging
wind potential with any bowing multicellular structures that
develop and move along the anticipated general northeastward storm
motion. Some guidance even suggests 0-6 km shear reaching to
around 30 kt, which would indicate better potential for convective
organization. Convection is expected to generally shift eastward
through the afternoon and early evening hours. Given the potential
for some damaging wind gusts, SPC has added a marginal severe
threat for today, and we have updated our local products to
reflect this potential as well. Forecast updates have been sent.
/DL/

Relevant portions of the prior discussion below:

Today and Tonight...Another mid/upper level shortwave is expected to
swing east across the ArkLaMiss today into tonight.  This, in
addition to the warm, moist, and unstable airmass over the region,
will yet again result in northeast moving scattered to numerous
showers and thunderstorms developing across the region during the
afternoon hours.

Some isolated activity will linger into the overnight hours.
However, much of it will dissipate early in the evening after sunset
as daytime heating and instability wane. Otherwise, highs today will
range from the upper 80s to middle 90s and lows tonight will fall
into the low and middle 70s. /19/

Tuesday through Sunday: Perturbed mid level zonal flow will
continue to enhance the diurnal convective threat through much of
the week. Passing mid level wave Wednesday may be of special
interest as it will be accompanied by good mid level lapse rates
with vertical totals in the upper 20s to around 30 and 20-30 knots
of deep layer shear. Agree with area outlooked by SPC as parameters
are best in these areas and will as such include in the HWO.

Ridging by the weekend will diminish the convective threat somewhat
while temperatures/heat indices begin rising. Damp conditions at the
surface will initially contribute to surface dewpoints in the lower
70s through max heating which will lead to sporadic heat indices
from 100 to 105. Due to expected convective potential continuing
into the weekend, duration of the high heat indices is somewhat
suspect. Thus, will hold off on mentioning in the HWO until that
picture becomes clearer./GG/

&&

.AVIATION...
06Z TAF discussion:
Despite clouds and some lingering shower activity across the area,
VFR flight categories are currently being observed at all sites.
Through the night, ceilings are expected to lower to MVFR, and
possibly IFR, categories as low stratus overspreads the area. Some
isolated convection will likewise remain possible through the
night as a warm moist and unstable airmass resides over the
region. Ceilings will improve through the morning, but convection
is again expected to break-out areawide across the area late
Monday morning through Monday afternoon. This will again result in
a periodic degradation of ceilings and visibilities to MVFR/IFR
categories where convection is observed on-station. Winds tonight
will remain light to calm from the south, increasing to between
5-10 knots from the south southwest by Monday afternoon. /19/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       90  70  88  71 /  74  56  58  21
Meridian      92  72  89  72 /  63  50  64  27
Vicksburg     89  72  89  73 /  72  53  47  16
Hattiesburg   93  71  90  73 /  64  49  69  16
Natchez       88  70  87  73 /  74  48  52  11
Greenville    87  71  89  73 /  65  54  47  22
Greenwood     88  72  88  73 /  68  60  56  26

&&

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

&&

DL/19/GG

Hazardous Weather Outlook...UPDATED
National Weather Service Jackson MS
828 AM CDT Mon Jun 17 2019

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
181330-
Ashley-Chicot-Morehouse-West Carroll-East Carroll-Richland-
Madison LA-Franklin LA-Catahoula-Tensas-Concordia-Bolivar-
Sunflower-Leflore-Grenada-Carroll-Montgomery-Webster-Clay-Lowndes-
Choctaw-Oktibbeha-Washington-Humphreys-Holmes-Attala-Winston-
Noxubee-Issaquena-Sharkey-Yazoo-Madison MS-Leake-Neshoba-Kemper-
Warren-Hinds-Rankin-Scott-Newton-Lauderdale-Claiborne-Copiah-
Simpson-Smith-Jasper-Clarke-Jefferson-Adams-Franklin MS-Lincoln-
Lawrence-Jefferson Davis-Covington-Jones-Marion-Lamar-Forrest-
828 AM CDT Mon Jun 17 2019

This hazardous weather outlook is for portions of southeast
Arkansas, northeast Louisiana, and central and south Mississippi.

.DAY ONE...Today and Tonight

SEVERE THUNDERSTORMS
THREAT...Marginal
TIMING...This afternoon through early this evening

Isolated severe storms, capable of producing damaging wind gusts,
are possible this afternoon through early this evening.

(https://www.weather.gov/images/jan/graphicast/1.png)

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Isolated severe thunderstorms are possible for extreme southeast
Arkansas, portions of northwest and north central Mississippi, and
portions of northeast Louisiana Wednesday through Wednesday
night. The primary hazards will be damaging wind gusts and large
hail.

(https://www.weather.gov/images/jan/graphicast/2.png)

.SPOTTER CALL TO ACTION STATEMENT...
The activation of storm spotters, HAM radio operators, and
emergency management personnel in support of severe weather
operations may be needed for portions of the region today and
Wednesday through Wednesday night.

DL

&&

...HAZARD LEGEND...

*SEVERE THUNDERSTORMS*
High...Significant severe thunderstorms are expected.
Moderate...Severe storms expected with significant
 severe weather possible.
Enhanced...Severe storms expected.
Slight...Severe storms possible.
Marginal...Isolated severe storms possible.

...USEFUL WEATHER WEB PAGES (URLS)...

NWS JAN Home page...
   https://www.weather.gov/jan
Stay Aware, Stay Safe NWS JAN Briefing Page...
   https://www.weather.gov/jan/safe
Latest Weather Briefing...
   https://www.weather.gov/jan/weather_briefing

Tropical page...
   https://www.weather.gov/srh/tropical?office=jan
National Hurricane Center Home Page...
   https://www.nhc.noaa.gov/
Find NWS JAN on Facebook...
   https://www.facebook.com/NWSJacksonMS
Follow NWS JAN on Twitter...
   @NWSJacksonMS
Follow NWS JAN on Youtube...
   https://www.youtube.com/user/NWSJacksonMiss

...ADDITIONAL URLS FOR SEVERE WEATHER ISSUES...

Storm Prediction Center (SPC)...
   https://www.spc.noaa.gov/
Meso Analysis...
   https://www.spc.noaa.gov/exper/mesoanalysis/
Day 1 through 3 Outlooks...
   https://www.spc.noaa.gov/products/outlook/
Storm Reports...
   https://www.spc.noaa.gov/climo/online/

Special Weather Statement
National Weather Service Jackson MS
1205 PM CDT Mon Jun 17 2019

MSZ061-171745-
Franklin MS-
1205 PM CDT Mon Jun 17 2019

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL FRANKLIN COUNTY UNTIL
1245 PM CDT...

At 1204 PM CDT, Meteorologists were tracking a strong thunderstorm
near Bude, or 18 miles northwest of Liberty, moving northeast at 25
mph.

Dime size hail and winds in excess of 40 mph will be possible with
this storm.

This strong thunderstorm will be near...
  Bude and Kirby around 1220 PM CDT.
  New Hope around 1235 PM CDT.

Other locations impacted by this storm include Meadville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

High winds can bring down trees and large limbs resulting in serious
injury or property damage. Exercise extreme caution when outdoors
during such strong winds...and be especially aware of older trees.

&&

LAT...LON 3161 9098 3161 9066 3135 9080 3135 9098
      3134 9099 3134 9100 3135 9101 3135 9102
      3134 9103 3133 9106 3134 9106 3133 9107
TIME...MOT...LOC 1704Z 206DEG 23KT 3140 9094

TW

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