Area Forecast Discussion
Issued by NWS Little Rock, AR

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FXUS64 KLZK 092332
AFDLZK

Area Forecast Discussion
National Weather Service Little Rock AR
632 PM CDT Thu Apr 9 2020

.AVIATION...10/00Z TAF CYCLE

VFR conds wl prevail thru the PD. Mid and high lvl clouds wl
gradually decrease fm the N later tngt and early Fri. /44/
&&

.PREV DISCUSSION...(ISSUED 251 PM CDT Thu Apr 9 2020)
SHORT TERM...Today Through Saturday

It`s been a little cooler across the Natural State today with
temperatures this afternoon in the upper 60s and lower 70s due to
the cold front that moved through the state early this morning.
Skies are mostly clear to partly cloudy, with surface winds
generally out of the north and east.

Highs today should top out in the upper 60s and 70s, with lows
tonight falling into the 30s and 40s. Some locations across the
north may see temperatures near freezing, but for the most part
temperatures should stay in the mid 30s across that portion of the
state. Cloud cover will return this evening across the majority of
the region as a short wave trough moves south through the East Texas
and Louisiana. Some slight chances for rain could be seen across the
far southern portions of the state, but for the most part, Arkansas
should remain dry.

The pleasant conditions should continue for Friday, with highs in
the upper 50s and lower 60s. Expect mostly dry conditions with clear
skies as brief high pressure builds over the region. Lows will drop
into the 40s Friday night.

Saturday will bring slightly warmer temperatures back to the
forecast as southerly surface flow returns and helps to advect
warmer and more moist air into the forecast area. Highs Saturday
should range from the mid to upper 60s and 70s. Unfortunately,
another shortwave trough is expected to move through the Lower
Mississippi Valley Region, which will return widespread rain chances
to the area on Saturday. Some thunderstorms cannot be ruled out,
however at this time no severe weather is anticipated.

LONG TERM...Saturday Night Through Thursday

The cut off upper low that had been hanging over southern California
over the past few days is expected to phase into the polar jet
stream as a strong shortwave trough dives south over the western
CONUS Rockies. This upper low is expected to weaken as it becomes
phased into the Canadian trough, but it looks to remain strong
enough to provide some significant large scale forcing for ascent
over Arkansas as it approaches Arkansas from early Sunday morning
throughout the day on Sunday. This trough is expected to move over
Arkansas Sunday afternoon as a neutrally tilted trough, which will
spread some differential temperature advection over the state,
increasing the instability for thunderstorms as the trough
approaches and eventually moves over the state on Sunday.

The strong large scale forcing for ascent will result in widespread
rain shower and thunderstorm activity over the state Sunday,
resulting in a wet Easter holiday for much of the state. The chances
for severe weather look to be conditional on the placement of the
warm sector as this trough moves over the state. A surface cyclone
will develop downstream of the upper trough on Sunday, and the
movement of the surface cyclone appears to be the primary factor on
where severe thunderstorms will develop across the region.

The GFS keeps the surface cyclone/low over far southern Arkansas,
moving east-northeast towards the Tennessee and Mississippi border
Sunday evening. If this solution pans out, thunderstorm activity
over Arkansas will likely remain elevated over a frontal inversion
with the warm front holding south of the CWA. In this scenario, the
southern third of the CWA may still see some severe thunderstorm
activity, but the only threats would be large hail and the potential
for flash flooding. Wind damage and tornado chances would be
extremely low in this scenario.

The ECMWF brings the surface cyclone/low a bit farther north into
Arkansas, still moving east-northeast, but moving over the
southeastern third of the CWA. For most of the state, thunderstorms
will remain elevated posing a hail and heavy rainfall/flash flooding
threat, however if the warm front pushes north into our southeastern
CWA, there may be a brief window for surface based thunderstorms
where the damaging wind and tornado threat could be enhanced Sunday
afternoon.

At this time have very high confidence in widespread showers and
thunderstorms across the state, so went ahead with 70 to 90 POPs for
much of the state on Easter Sunday. Think that the warm sector will
struggle to recover favoring the slightly farther south trajectory
of the surface low advertised in the GFS, keeping the primary severe
weather threat south of our CWA. Elevated thunderstorms capable of
producing large hail and locally heavy rainfall with the possibility
for flash flooding. The threat for large hail and flooding appear to
be maximized over the southeastern half of Arkansas as locations
farther north will be deeper in the cold air limiting the magnitude
of elevated instability and reducing the efficiency of rainfall
production due to lower absolute humidity/PWAT values.

Next week...

A strong cold front will move across the state Sunday night bringing
much drier and cooler air across Arkansas. The dry air will bring a
quick end to precipitation as the front moves through, but it will
also bring temperatures down into the lower to mid 30s across the
Ozarks Monday morning. In far northwest Arkansas, there is a chance
that temperatures may briefly fall to or below the freezing mark,
with much of the Ozarks seeing low temperatures hovering just above
freezing and up to the mid-30s. Do not think a widespread freeze is
likely across northwest Arkansas because northwesterly winds are
expected to hold up in the 5-10 mph range overnight, helping to keep
the low-level atmosphere mixed and reducing the effects of cold air
drainage in valleys in the Ozarks. Went ahead and mentioned areas of
frost in the forecast for Monday morning, but will have to keep a
close eye on temperatures to highlight any chances of freezing
temperatures Monday morning if the air behind the front is colder
than currently forecast.

For the remainder of the week, a large scale trough will remain over
the eastern two thirds of the CONUS which will tend to keep
temperatures near or below normal temperatures for this time of
year. Have some chances for rain showers in the forecast on Tuesday
and Thursday as relatively weak shortwave troughs moves through the
larger scale trough aloft. Kept POPs in the 20-30 range for right
now as there will not be a whole lot of moisture to work with, and
the rain showers look to remain scattered in nature at this time.
There is no indication of any chance for severe weather, and do not
even have thunder in the forecast at this time. It looks like we
will remain warm enough aloft and near the surface to prevent any
precipitation from falling in a wintry form, so just expect some
periods of light rain Tuesday and Thursday at this time.

Cavanaugh

&&

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

$$


Aviation...99



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