Special Weather Statement, NWS Jackson, MS

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
717 AM CST Mon Jan 2 2017

...SEVERE WEATHER AND HEAVY RAIN EXPECTED TODAY...

.UPDATE...
Updated for morning discussion.

&&

.DISCUSSION...
Made a quick update to the forecast to remove the Dense Fog Advisory.
The combination of the warm front lifting north of the region and the
storms this morning have just about reduced the risk of dense fog.
Some patchy fog will continue to be possible through the morning but
visibilities should remain above one quarter of a mile. Latest
observation trend also shows that dense fog has not been panning out
as much across the area. Update products already out. /28/

Prior discussion below:

Today through Tonight

Latest vapor imagery showed the intense shortwave trough, which will
develop our severe weather for today, over the Southern Plains.
Meanwhile, areas of dense fog continued over the advisory area. This
was ahead of an advancing warm front from the south with 60s
dewpoints in its wake. Some locations in the southern and eastern
part of the advisory area have already been affected by rain and seen
the warm front passage, thus were removed from the advisory for the
rest of the morning. Some fog will be possible but think that the
prevalence of dense fog is a lower chance. Overall the fog should
lift by 8 am. Also area radars were already showing showers and
isolated strong elevated thunderstorms coming from Southern
Louisiana. This activity was developing in advance of a stronger low
level jet.

Otherwise the main focus will be the severe potential for this
afternoon into early this evening. Models have been consistent with
the track of this short wave in recent model runs. This fast
progressive pattern will bring the negatively tilted shortwave
trough to the forecast area by 00z today. The warm front will make
better progressive north across Mississippi for today which will
spread an unstable airmass across the region with middle 60s
dewpoints. However with some morning showers and embedded
thunderstorms pushing into our western and central areas this
morning ahead of the severe convection for this afternoon, this may
hamper airmass recovery some for this afternoon. This concern was
shown by one of the short range models, while the NAM, GFS, and
other short range models showed good recovery for this afternoon.
However with the strong dynamics of this system will assume that
there will be enough recovery for severe thunderstorms to take place.
As the system approaches, the warm front will make greater northward
progress over our forecast area, which will bring in some good
instability from the south. This shortwave will be preceded by a
surface wave on a pacific type front coming from the west. Looking at
some of the dynamics, we will be in the left front quad of the upper
jet as the low level jet increases across the region, midlevel
southwest jet of 70 knots, and midlevel lapse rates 7C. The 0-3 km
bulk shear will be around 30-50 knots in southwest flow, which will
be favorable for severe weather as discrete supercells comes ahead of
the broken QLCS line. Could get some tornadoes with the discrete
supercells. The general timing looks to be for this afternoon into
early this evening for the squall line to push through the region.
Will continue to highlight damaging winds, large hail and possible
tornadoes in an elevated risk in the HWO but push back the current
timing of the severe weather a little. Since the Pine Belt area has
received several inches of rainfall in the last few days will
continue to highlight the limited flash flooding potential there with
an additional 2 to 3 inches of rainfall possible. Our bout of severe
weather should exit the region with the front early this evening. The
rains will end from west to east in the wake of the departing
shortwave overnight as the front exits the region.

As far as temps are concerned, anomalous low level warming will help
to keep highs and lows around 15 to 20 degrees above normal. Readings
will range from the spring like lower to middle 70s. Lows will be
from the lower to upper 50s. As for POPs, will keep the current high
POPs for today across the CWA. The best POPs for tonight will be
across our northeast for early this evening as the rains depart
overnight./17/

Tuesday through the weekend...

By Tuesday morning, the upper level system will be to our east and
cold high pressure at the surface will be dropping south into our
region. The cold air will lag just a bit on Tuesday as highs should
still warm nicely into the 70s. However, cold advection will be in
full force once that 1037mb high starts to have some affect on our
region following a weak cold frontal passage late Tuesday into early
Wednesday. However, models do indicate that this surface high won't
completely reach our CWA but should affect the northern portions and
it is in this location where the colder highs should be on
Wednesday. Dry weather will continue through the week but much
colder temperatures will prevail as highs will be in the 40s across
the north to the lower 50s in the south. Overnight lows will again
dip below freezing north of I-20 on Thursday morning and areawide on
Friday morning. In fact, some locations in the north could see lows
Friday morning in the lower to mid 20s.

Heading into the weekend, there remains disagreement among the
operational models as to our next chance for precipitation. The
Canadian and ECMWF appear to be the most in sync with bringing
moisture and precip back to the region from the west later in the
day on Friday. As a disturbance moves to our south, moisture will
remain across our region going into Friday night. This will combine
with cold temperatures already in place to bring the threat for some
wintry precipitation. At this time, it looks like there is some
potential for a rain/snow mix or just some snow, especially for
locations along and north of I-20. The operational GFS is most
different with this system as it develops more of a trough and sfc
low moving across Arkansas, and keeping temperatures on the warm
side. This would lead to strictly a rain scenario. All models do
indicate any precipitation that does develop will exit the region by
Saturday afternoon/night with temperatures continuing to feel like
winter. /28/

&&

.AVIATION...
12Z TAF discussion:
Showers and storms continue to track north/northeast across the
ArkLaMiss as a warm front moves north as well. Some of these storms
might be strong this morning with hail being the primary risk. In
addition, patchy fog will also be possible and some locations along
and north of I-20 could see some dense fog, reducing vis to 1/4sm or
less at times. Fog issues should improve after daybreak. Widespread
IFR to LIFR categories are occurring this morning thanks to either
reduced vis/ceilings from the fog or the storms. Additional storms
are expected this afternoon from the west. Some of these storms will
be severe as well. These will reduce flight categories to MFR to LIFR
this afternoon. Rain will exit from west to east by this evening, but
some patchy fog will again be possible. Overall, not good flying
weather expected today. /28/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       74  57  70  46 /  97  46   7   7
Meridian      73  59  71  49 /  98  57   8   5
Vicksburg     75  54  71  46 /  99  35   3   8
Hattiesburg   75  58  73  51 /  98  36   5   4
Natchez       74  54  72  48 /  99  26   2   7
Greenville    70  54  68  41 /  99  53   6  10
Greenwood     73  56  68  42 /  98  64   9  10

&&

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

&&

28

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Special Weather Statement
National Weather Service Jackson MS
640 AM CST MON JAN 2 2017

MSZ046-021315-
Kemper MS-
640 AM CST MON JAN 2 2017

...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN KEMPER COUNTY UNTIL
715 AM CST...

At 640 AM CST, Meteorologists were tracking a strong thunderstorm
near Boyd, or 10 miles northeast of Lauderdale, moving northeast at
40 mph.

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

This storm will remain over mainly rural areas of southeastern Kemper
County.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3258 8839 3258 8847 3264 8854 3280 8837
      3277 8836
TIME...MOT...LOC 1240Z 229DEG 35KT 3263 8840

17

Special Weather Statement
National Weather Service Jackson MS
642 AM CST MON JAN 2 2017

MSZ018-019-025-021315-
Bolivar MS-Leflore MS-Sunflower MS-
642 AM CST MON JAN 2 2017

...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN BOLIVAR...NORTHERN
SUNFLOWER AND NORTHWESTERN LEFLORE COUNTIES UNTIL 715 AM CST...

At 642 AM CST, Meteorologists were tracking a strong thunderstorm
over Boyle, or near Cleveland, moving northeast at 45 mph.

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

This strong thunderstorm will be near...
  Ruleville around 655 AM CST.
  Drew around 700 AM CST.
  Parchman around 710 AM CST.
  Rome around 715 AM CST.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3397 9045 3381 9045 3381 9031 3356 9082
      3370 9088 3399 9054 3399 9046
TIME...MOT...LOC 1242Z 228DEG 40KT 3368 9075

17

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JACKSON MS
725 AM CST MON JAN 02 2017

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

0642 AM     LIGHTNING        4 W FLOWOOD             32.32N 90.17W
01/02/2017                   HINDS              MS   BROADCAST MEDIA

            HOUSE ON LINDEN PLACE CAUGHT ON FIRE LIKELY DUE TO
            LIGHTNING.

&&

JCULIN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JACKSON MS
732 AM CST MON JAN 02 2017

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

0720 AM     FLASH FLOOD      BRANDON                 32.28N 90.00W
01/02/2017                   RANKIN             MS   LAW ENFORCEMENT

            SEVERAL ROADS WERE FLOODED INCLUDING PINEBROOK DRIVE AND
            CASTLEWOODS BOULEVARD

&&

27

Special Weather Statement
National Weather Service Jackson MS
734 AM CST MON JAN 2 2017

MSZ064-065-072-073-021415-
Marion MS-Lamar MS-Jefferson Davis MS-Covington MS-
734 AM CST MON JAN 2 2017

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN LAMAR...
SOUTHEASTERN COVINGTON...NORTHEASTERN MARION AND SOUTHEASTERN
JEFFERSON DAVIS COUNTIES UNTIL 815 AM CST...

At 734 AM CST, Meteorologists were tracking a strong thunderstorm
near Columbia, moving northeast at 35 mph.

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

This strong thunderstorm will be near...
  Improve around 745 AM CST.
  Melba around 755 AM CST.
  Sumrall around 800 AM CST.
  Collins and Sanford around 815 AM CST.

Other locations impacted by this storm include Seminary.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3128 8983 3167 8960 3155 8940 3146 8940
      3143 8943 3143 8945 3141 8945 3122 8967
TIME...MOT...LOC 1334Z 215DEG 31KT 3128 8974

JC