Area Forecast Discussion
Issued by NWS Little Rock, AR

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FXUS64 KLZK 211126 AAA

Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
526 AM CST Sat Jan 21 2017

VFR conditions will prevail initially, then will deteriorate by
late this afternoon, as showers and thunderstorms develop and move
into the area. Conditions will likely be mvfr through the night
tonight, temporarily restricted to ifr in heavier precipitation.

.PREV DISCUSSION...(ISSUED 344 AM CST Sat Jan 21 2017)

SHORT TERM...Today Through Sunday Night
Early this morning, a frontal boundary was located stalled in the
vicinity of the Gulf coast. Surface low pressure along the
boundary continued to push Gulf moisture into southeast Arkansas,
with light showers noted. These will move out of the region later
on this morning, as the surface low heads eastward.

Southerly flow, along with breaks in clouds, will allow for
temperatures to climb well above average today. Highs will top out
in the 60s to lower 70s.

In the upper levels, southwest flow will push the stalled surface
boundary along the coast back to the north as a warm front this
afternoon. Surface low pressure will form along the boundary, with
a negatively tilted upper trough approaching and a cutoff upper low
developing and moving down into the southern plains.

Showers and thunderstorms will develop and spread into Arkansas
this afternoon and evening, as the upper system approaches, and
uplift occurs with the surface low.

Strong to severe storms are possible, with the greatest threat
during the overnight hours. Even though we will be losing the
heating of the day, the surface and upper systems will be nearly
in phase with each other, which will enhance buoyancy over the
region. Not only that, very cold air aloft will be present.
Stronger storms will be capable of producing very large hail (in
excess of two inches in diameter). Given the amount of wind shear
present (especially a 50+ knot mid level and upper level jet), and
potentially backing winds at the surface, any discrete cells that
develop in the warm sector of the system would have the potential
for rotating updrafts. Thus, there will be a tornado threat into
the night.

By late in the night or early Sunday morning, storms could
consolidate into more of a linear mode over eastern Arkansas.
Additional storms will be possible along and behind the front,
with a continued hail threat into the day Sunday. There may be a
brief break in precipitation during the morning, as a dry slot
moves across behind the overnight storms, and ahead of the
approaching frontal boundary. Any lingering precipitation should
move out of Arkansas during the evening Sunday, as the upper low
moves into the Ohio Valley.

I`ll break down the severe threats...
Very large hail in excess of two inches in diameter...
The greatest possibility will be from 6 PM to 6 AM, and in areas
generally east of Interstate 30 and south of Interstate 40.

The greatest possibility will be between 6 PM and Midnight, and in
areas generally east of the Ozark and Ouachita Mountains.

Damaging Wind Gusts in Excess of 60 MPH...
The greatest possibility will be between Midnight and 6 AM, and in
areas generally east of the Interstate 30 and US 67 corridor.

Hail less than one inch in diameter...
The greatest possibility will be between about 9 AM and 6 PM over
much of Arkansas. This would be on the back edge of the upper low,
with any stronger storms that develop.

LONG TERM...Monday Through Friday
With an upper level ridge over the central U.S. Monday, northwest
flow will be over Arkansas. As the ridge moves east Tuesday, an
upper low will move into the Plains. The upper low moves through the
Great Lakes Wednesday as a broad trough extends into the Four
Corners area. This broad trough moves south and east Thursday
night and Friday. Northwest flow will be over Arkansas Thursday
and Friday.

Models are in good agreement for the long term. Surface high
pressure will be over the area to begin the long term period with
dry weather. The ridge moves to the east coast Tuesday night. Early
Tuesday a warm front moves through the state, then a cold front
moves through Tuesday night. With limited moisture available, do not
expect any precipitation with the front. A short wave will move
through the southwest flow Wednesday night and Thursday and again
dry conditions are expected. Cooler air will be behind the front
with highs in the 40s and 50s Thursday and Friday instead of 50s
and 60s which will be seen Monday through Wednesday.

No significant fire weather issues are expected through the
period. Minimum humidity will remain above 50 percent. Winds are
expected to remain below critical thresholds.


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


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