Special Weather Statement, NWS Little Rock, AR

Area Forecast Discussion
National Weather Service Little Rock AR
1259 AM CDT Mon Oct 11 2021

.UPDATE...

Updated to include the 06z aviation discussion.

.AVIATION...

SHRA/TSRA are expected to sweep across the state tonight into
Monday. A few TSRA's over Wrn terminals may pose a damaging wind
threat along the leading edge of the convection. VFR conds should
deteriorate to MVFR/IFR with the arrival of precipitation. Winds
will remain elevated through the period with switching from the
S/SW to the W/NW behind the Pacific cold front. Conds will improve
back to VFR from W to NE on Monday.

&&

.PREV DISCUSSION...(ISSUED 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...70

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.

70/44/67

Special Weather Statement
National Weather Service Little Rock AR
233 AM CDT Mon Oct 11 2021

ARZ041-042-052-110815-
Pike AR-Garland AR-Montgomery AR-
233 AM CDT Mon Oct 11 2021

...A strong thunderstorm will impact portions of northern Pike,
southwestern Garland and southeastern Montgomery Counties through 315
AM CDT...

At 233 AM CDT, Doppler radar was tracking a strong thunderstorm near
Daisy, or 13 miles north of Murfreesboro, moving northeast at 40 mph.

HAZARD...Winds in excess of 40 mph and half inch hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Glenwood...                       Norman...
Daisy...                          Narrows Dam...
Meyers...                         Daisy State Park...
Bear Creek Public Use Area...     Salem in Pike County...
Crystal Springs Landing...        Welsh...
Sunshine...                       Rosboro...
Lodi...                           Silver...
Fancyhill...                      Hopper...
Kirby...                          Pearcy...
Hurricane Grove...                Crystal Springs...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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

&&

LAT...LON 3454 9362 3467 9343 3445 9321 3440 9328
      3440 9341 3434 9341 3434 9348 3427 9348
      3410 9373 3425 9387
TIME...MOT...LOC 0733Z 231DEG 35KT 3426 9369

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

46