Severe Thunderstorm Warning 243, NWS Little Rock, AR

891 
WWUS54 KLZK 110604
SVSLZK

Severe Weather Statement
National Weather Service Little Rock AR
104 AM CDT Mon Oct 11 2021

ARC113-127-110630-
/O.CON.KLZK.SV.W.0243.000000T0000Z-211011T0630Z/
Polk AR-Scott AR-
104 AM CDT Mon Oct 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 130 AM CDT
FOR POLK AND SOUTH CENTRAL SCOTT COUNTIES...

At 103 AM CDT, strong to severe thunderstorms were located along a 
line extending from near Polk County Fairgrounds to near Grannis to 
6 miles west of Horatio, moving east at 45 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Mena...                           Wickes...
Grannis...                        Hatfield...
Vandervoort...                    Opal...
Cossatot River State Park...      Polk County Fairgrounds...
Mena Intermountain Airport...     Mccauley...
Shady...                          Hartley...
Bard Springs Recreation Area...   Caney Creek Wilderness...
Cove...                           Acorn...
Big Fork...                       Board Camp...
Ink...                            Shady Lake Recreation Area...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 400 AM CDT for western
Arkansas.

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3463 9441 3474 9393 3435 9394 3436 9425
      3427 9426 3427 9425 3423 9424 3419 9425
      3419 9441
TIME...MOT...LOC 0603Z 257DEG 38KT 3454 9429 3424 9429 3391 9446 

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

46

Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
634 PM CDT Sun Oct 10 2021

.DISCUSSION...

Updated to include the 00Z aviation discussion below...

&&

.AVIATION...

While calm conditions are ongoing early this Sun evening...a storm
system to the west will move through tonight into Mon
morning...with convection becoming likely for many sites. Storms
will impact the first terminals across the NW and W after
midnight...then later towards sunrise further east. Some
improvements are expected by midday Mon for most terminals...and
likely all sites by the end of this TAF period.

&&

.PREV DISCUSSION...(ISSUED 258 PM CDT Sun Oct 10 2021)

SHORT TERM...Tonight Through Tuesday

Current satellite imagery shows thunderstorms initiating in the
vicinity of the dryline and frontal boundary out in the Texas
Panhandles region. Zooming out, it's quite evident the upper low
that was invof the four corners region this morning has started to
push east/northeast.

Storms will continue to increase in coverage and intensity over
Texas and Oklahoma with all modes of severe weather possible...
especially from the Red River Valley and I-35 corridor eastward.
The line of storms will shift eastward during the evening and
overnight hours.

Though there's some slight temporal variation in short term/
mesoscale model solutions, it seems to be a safe bet that activity
will largely stay west of Arkansas through the evening. As the
storms shift into Arkansas (primarily after 06Z), they will tend
to weaken...especially as they shift into central Arkansas.

Concerning the severe threat in Arkansas...
The Northwest 1/3rd of the state still appears to be the favored
area...essentially from Texarkana to Conway and Mountain Home
westward. What will be working against the severe threat is the
time of day and lack of large scale heating ahead of the boundary.
However, as I've said before, this is a very dynamic system.
There's backing winds out ahead of the approaching boundary, and a
great deal of vertical wind shear with the system. The low level
jet will get going as well, with model forecast soundings showing
50+ knots around and above 2000 feet late in the night and early
tomorrow morning. Couple this with some elevated CAPE and cold air
aloft, and it should be enough to sustain a severe threat well
into Arkansas for several hours.

The storms will weaken as they shift into central Arkansas, with
drier air moving in behind the frontal passage, which should be
during the morning hours. As it hits the upper ridge centered over
the western Gulf of Mexico, it will stall out to the south of us.
But, more on that a little later.

As for the mode of storms and associated threats...
The primary tornado threat will be with the initial storms over
far western/northwest Arkansas. Otherwise, damaging wind gusts
will be the primary concern with any strong/severe thunderstorms.

Hail can't be ruled out either, but the colder air aloft will lag
the surface system somewhat, so the hail threat will be greater
over far western Arkansas.

Basically, as the system shifts eastward into central Arkansas,
this will evolve into more of a qlcs-type setup versus a single
line. Unfortunately, based on the amount of shear, there will be a
continued weak tornado threat, and if you've got any experience
with severe weather in these parts, spin up and dissipate quickly
and are not easy to warn for.

High precipitable water values (on the order of around two
inches) will allow stronger storms to be efficient rainfall
producers. Would not be surprised to see localized areas of heavy
rainfall, but nothing widespread as the overall storm motion
should be...well...fast.

Other concerns...
Have increased the wind and wind gust forecasts over the entire
area to account for the wind energy associated with the system...
especially over the higher terrain of the Ozarks and Ouachitas.
Also included a mention of gusty winds associated with
thunderstorms from around/after midnight through mid day tomorrow.

The gradient will relax after the frontal passage, with winds
diminishing during the afternoon Monday. Slightly cooler temps
will be noted. However, weak surface high pressure will move
through pretty quickly behind the front. By Tuesday, the upper
ridge over the western Gulf will expand toward the southeast
conus, and this will shift the stalled front back to the north as
a warm front.

Showers/storms will become possible by Tuesday afternoon as the
warm front shifts northeastward and promotes uplift into the
region.

Okay...I'm done for now. I'll let the long term forecaster take
over...

LONG TERM...Tuesday Night Through Sunday

Sfc warm front will continue to lift north of the area at the start
of the period with Td values approaching 70 F statewide Wednesday.
Aloft, an intensifying cyclone will lift northeastward from the
Central Rockies toward the Upper MS Valley against steadfast ridging
across the SE US.

While the H500 ridge will keep the mid-week cyclone at bay, it will
also help funnel moisture from what is expected to be Pacific
Hurricane Pamela. Pamela is expected to make landfall east of the
tip of the Baja Peninsula. From there, an abundance of moisture will
stream northeast across southern Texas northeastward over Arkansas.
Model data suggests PW values in the 2-2.5 inch range across this
corridor, which for several U/A sites would be near daily record max
values.

By late week a new mid-level through will begin to traverse the
country from west to east as the SE US ridge begins to finally
yield. A cold front will approach the area from the NW and interact
with the abundance of moisture in place and provide widespread
shower and thunderstorm activity to the region. Some locally heavy
rain will become a concern before precip exits the area on Saturday
when the front has moved through. In its wake, cooler and perhaps
below average temperatures will build in over the state.

&&

.LZK Watches/Warnings/Advisories...NONE.
&&

Aviation...62

Hazardous Weather Outlook...UPDATED
National Weather Service Little Rock AR
303 PM CDT Sun Oct 10 2021

ARZ003>008-012>017-021>025-030>034-037>047-052>057-062>069-112015-
Boone-Marion-Baxter-Fulton-Sharp-Randolph-Newton-Searcy-Stone-
Izard-Independence-Lawrence-Johnson-Pope-Van Buren-Cleburne-
Jackson-Logan-Conway-Faulkner-White-Woodruff-Scott-Yell-Perry-
Polk-Montgomery-Garland-Saline-Pulaski-Lonoke-Prairie-Monroe-Pike-
Clark-Hot Spring-Grant-Jefferson-Arkansas-Dallas-Cleveland-
Lincoln-Desha-Ouachita-Calhoun-Bradley-Drew-
303 PM CDT Sun Oct 10 2021

This Hazardous Weather Outlook is for a Large Part of Arkansas.

.DAY ONE...This Afternoon and Tonight

A strong pressure gradient remains in place over the region and
strong to gusty southwesterly winds will continue today and
tonight. Wind speeds of 10-20 mph with gusts in excess of 30 mph
will be possible, particularly in the higher terrain of the
Ouachita and Boston Mountains.

Severe weather will be possible across western and northwestern
Arkansas tonight. Damaging wind gusts and isolated tornadoes will
be most favored, however large hail will also be possible. Heavy
rainfall with amounts of one to two inches may be seen over
portions of northwestern Arkansas as well.

.DAYS TWO THROUGH SEVEN...Monday Through Saturday
Showers and thunderstorms will be possible over mainly eastern
Arkansas on Monday with locally heavy rainfall possible.

Shower and thunderstorm chances will remain in the forecast through
late week as an active pattern remains. While the potential for
strong to severe storms will exist during this time, uncertainty is
too great for specifics at this time. Some locally heavy rainfall
could become a concern over parts of the state.

.Spotter Information Statement...

Spotter activation will not be needed through this evening, but
could be needed late tonight over western Arkansas.

&&

Visit NWS Little Rock on the web. Go to http://weather.gov/lzk.

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