Special Weather Statement, NWS Little Rock, AR

Area Forecast Discussion
National Weather Service Little Rock AR
228 PM CST Wed Dec 29 2021

.SHORT TERM...Tonight Through Friday

Early afternoon water vapor satellite imagery shows a large upper
trough extending over almost the entire country of Canada and then
southwest over most of the United States, west of the Rocky
Mountains. This trough represents a fairly typical core of cold air
bottled up in Canada, but does extend over most of the western
United States which is what will drive our weather pattern here over
the next several days. With an upper level ridge parked over the
eastern United States, this will leave Arkansas in a southwest flow
regime through the end of the year. One shortwave trough moving
northeast in this regime is what is driving showers and
thunderstorms across Arkansas this afternoon (Wednesday) and
evening.

For this afternoon and evening, there is a core of convective
potential instability extending from Calhoun County northeast
through Desha county where a corridor of very strong to severe
thunderstorms will likely continue through early this evening. This
general area is under a tornado watch through 7 PM CST, but
thunderstorms may move through this corridor in the 2 to 5 PM
timeframe. Large hail and damaging winds are the primary threats
with these storms, but these storms will likely be organized, and
could be supercells, so tornadoes are certainly possible as well.
The low-level shear environment isn't overly supportive of
tornadogenesis, but supercell thunderstorms can easily distort local
wind patterns to make tornadoes more or less likely.

The main corridor of showers and thunderstorms will move east this
evening, but there will be no frontal boundary to clear out low-
level moisture as is the usual case behind some of these severe
weather producing systems. In fact, once storms move east of the
state, a significantly drier air mass build over the state from the
850 mb level to the top of the troposphere. This will lead to
clearing skies aloft overnight...but no real loss of low-level
moisture. This looks to provide an ideal environment for the
development of fog across the state overnight. Went ahead and issued
a dense fog advisory for most of the state to account for the
potential for visibilities of one quarter or less from approximately
midnight tonight through the mid-morning hours of Thursday.

A significantly strong shortwave trough will move through the base
of the western CONUS trough leading to strong lee-side cyclogenesis
and the surge of Gulf moisture to the north across the state
throughout the day on Friday. We may see some showers and
thunderstorms develop on the warm/moist Gulf air mass moving across
the state during the day on Friday. However, the strongest large
scale forcing for ascent is not expected to move over the state
until Friday evening/New Year's Eve.

Cavanaugh

&&

.LONG TERM...Friday Night Through Wednesday

Not a lot of value added changes will be forth coming this forecast
cycle as medium range models remain in overall decent agreement, at
least in the synoptic scale. Of course here are the usual timing and
placement issues one would expect with in this time frame but these
differences are not enough to favor one model over another. That
being said, a blend of model solutions will be used.

Forecast remains challenging to say the least with both severe
weather chances and a significant change in air mass to contend
with. Temperatures come Sunday morning could be as much as 50
degrees colder in spots versus high temperatures on Friday. While
2021 will be ending very mild, the start of 2022 will remind us all
it is still winter.

The period initiates with a highly amplified upper pattern in place.
A large and well pronounced trough will be located from the Rockies
into the Great Basin and into the desert southwest. The persistent
southeast ridge will be compressed from where it has been placing
the areas in southwest flow aloft.

On the surface, a powerhouse of cold front will be located from the
Texas/Oklahoma panhandles and into central Missouri. A leading wave
kicking out of the primary trough will initiate widespread showers
and thunderstorms across the area. As this upper feature approaches,
surface low pressure will strengthen in response and traverse the
aforementioned front, dragging it into and eventually through the
state.

Low level nocturnal jet in excess of 50 mph will develop Friday
evening with significant height falls and large scale ascent noted
as the upper trough approaches. As such, there will be a window for
strong to severe thunderstorms in the Friday night until the front
exits the state early Saturday afternoon. It appears that central
Arkansas and points east and southeast will be most susceptible to
severe weather with all modes of severe weather possible including
tornadoes with favorable low level shear.

There are still a few caveats to consider with this event, mainly
timing of the fropa, fairly weak instability and the fact the lead
impulse really has not been sampled by the upper air network.
Regardless, the overall dynamics of this system should be able to
overcome any of these restrictions. In addition, PWAt values are
extremely high at 1.5 inches or higher and locally heavy rain is a
concern with the GFS particularly aggressive with its QPF. It still
appears that this event will be all liquid as moisture will pull out
before the coldest of the air arrives. There is a band of moisture
rotating around the parent low Sunday morning that brushes the north
and while it may bring a stray flurry, no snow will be added to the
grids at this time.

Once the the primary cold front moves through, a secondary front in
association with the upper trough moves through and brings colder
air back to the area and will do so very quickly. Temperatures will
be dropping Saturday afternoon and into Sunday morning as strong
cold air advection occurs. Northwest winds Sunday morning could
produce wind chill values in the single digits or even less and this
area will need to be watched for a possible wind chill advisory.

High pressure will then pass over the area Sunday and Monday with
clear skies and slowly moderating temperatures as winds shift back
to the southwest. Moisture does begin to creep back into the state
late in the period but no pops will be added at this point.

Goudsward

&&

.PRELIMINARY POINT TEMPS/POPS...
Batesville AR     47  66  52  70 /  10   0  10  30
Camden AR         54  72  55  76 /  10   0  10  20
Harrison AR       41  65  50  68 /   0   0   0  40
Hot Springs AR    49  68  52  72 /   0   0   0  30
Little Rock   AR  51  67  54  73 /   0   0  10  30
Monticello AR     56  73  59  77 /  20   0  10  20
Mount Ida AR      46  69  51  71 /   0   0  10  30
Mountain Home AR  44  64  48  69 /   0   0   0  40
Newport AR        49  63  53  70 /  10   0  10  20
Pine Bluff AR     54  70  56  76 /  10   0  10  20
Russellville AR   47  68  50  72 /   0   0  10  40
Searcy AR         47  66  51  72 /  10   0  10  20
Stuttgart AR      54  69  56  74 /  10   0  10  20
&&

.LZK Watches/Warnings/Advisories...
Dense Fog Advisory from 11 PM this evening to 10 AM CST Thursday
FOR Arkansas-Baxter-Boone-Bradley-Calhoun-Clark-Cleburne-
Cleveland-Conway-Dallas-Desha-Drew-Faulkner-Fulton-Garland-Grant-
Hot Spring-Independence-Izard-Jackson-Jefferson-Johnson-Lawrence-
Lincoln-Logan-Lonoke-Marion-Monroe-Montgomery-Newton-Ouachita-
Perry-Pike-Polk-Pope-Prairie-Pulaski-Randolph-Saline-Scott-
Searcy-Sharp-Stone-Van Buren-White-Woodruff-Yell.

&&

Short Term...66 / Long Term...56

Hazardous Weather Outlook...UPDATED
National Weather Service Little Rock AR
1107 AM CST Wed Dec 29 2021

ARZ003>008-012>017-021>025-030>034-037>047-052>057-062>069-301100-
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-
1107 AM CST Wed Dec 29 2021

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

.DAY ONE...Today and Tonight

Dense fog is being observed across the state and will continue
across the afternoon. This will lead to hazardous driving
conditions due to the low visibility.

In addition, showers and thunderstorms will be ongoing or will be
developing for most of today. Where the stronger storms do
develop, locally heavy is expected with some flash flooding
possible.

Some of these storms could be severe mainly across portions of
southeastern Arkansas. Generally in locations to the south and
east of Interstates 30 and 40. With these strong storms all modes
of severe weather will be possible.

.DAYS TWO THROUGH SEVEN...Thursday Through Tuesday

A strong cold front will approach the state on Friday bringing the
chance for strong to severe thunderstorms across the state from
Friday afternoon into Saturday morning. In addition to the
possibility of severe weather, locally heavy rainfall will also be
possible. Strong S-SW winds will be seen across the state in advance
of the front with gusts approaching 30 mph at times.

Behind the front, significantly colder air will move into the state.
Wind chill values Sunday morning are expected to be in the single
digits or lower across northern Arkansas. W-NW winds behind the
front will be strong with gusts approaching 30 mph at times.

.Spotter Information Statement...

Spotter Activation May Be Needed

&&

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

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LITTLE ROCK AR
1151 AM CST WED DEC 29 2021

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

1105 AM     FLASH FLOOD      LITTLE ROCK             34.72N  92.35W
12/29/2021                   PULASKI            AR   BROADCAST MEDIA

            STREET FLOODING WAS REPORTED IN THE METRO.

&&

EVENT NUMBER LZK2100784

61

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LITTLE ROCK AR
232 PM CST WED DEC 29 2021

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

0217 PM     HAIL             HERMITAGE               33.45N  92.17W
12/29/2021  E1.00 INCH       BRADLEY            AR   PUBLIC

            QUARTER SIZE HAIL WAS REPORTED AT THE DOLLAR GENERAL IN
            HERMITAGE.

&&

EVENT NUMBER LZK2100785

61

Special Weather Statement
National Weather Service Little Rock AR
239 PM CST Wed Dec 29 2021

ARZ057-064-065-069-292130-
Drew AR-Lincoln AR-Desha AR-Arkansas AR-
239 PM CST Wed Dec 29 2021

...A strong thunderstorm will impact portions of northwestern Desha,
northeastern Drew, southeastern Lincoln and southeastern Arkansas
Counties through 330 PM CST...

At 239 PM CST, Doppler radar was tracking a strong thunderstorm 8
miles southeast of Cane Creek State Park, or 11 miles southeast of
Star City, moving east at 40 mph.

HAZARD...Wind gusts of 50 to 55 mph and nickel size 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...
Dumas...                          Gould...
Mitchellville...                  Watson...
Winchester...                     Yancopin...
Omega...                          Mills...
Merrisach Lake...                 Trusten Holder WMA...
Arkansas Post...                  Garrett Bridge...
Pendleton...                      Gourd...
Florence...                       Tyro...
Rose Hill...                      Reedville...
Morgan Point Recreation Area...   Yukon...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

A Tornado Watch remains in effect until 700 PM CST for southeastern
Arkansas.

&&

LAT...LON 3371 9178 3387 9184 3412 9119 3386 9109
TIME...MOT...LOC 2039Z 251DEG 36KT 3381 9173

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH

44