Area Forecast Discussion
Issued by NWS Little Rock, AR

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FXUS64 KLZK 111121 AAA
AFDLZK

Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
521 AM CST Mon Dec 11 2017

.DISCUSSION...

Updated to include the 12Z aviation discussion below...

&&

.AVIATION...

Light and variable winds this morning will increase this
afternoon...with some gusts over 20 kts possible. Highest winds
will be across NRN AR. SW winds will switch to the NW...from NW AR
to the SE as a new front moves into the area late this afternoon
through this evening. Winds this evening should decrease
some...with sustained winds below 10 kts. VFR CIGS/VIS will
persist through the period however.

&&

.PREV DISCUSSION...(ISSUED 233 AM CST Mon Dec 11 2017)

SHORT TERM...Today Through Tuesday Night

Fire danger concerns will continue to be the primary forecast concern
in the short term period...

Moisture levels remain low early this morning...with dewpts
remaining in the 20s to near 30. Winds remain light...but the SFC
pressure gradient will tighten later in the morning. Expect SW winds
to increase to 15 to near 20 kts across the Ozarks and MS Delta
region of the CWA...with 10 to 15 kts expected across central to SW
portions of the CWA. Winds will then switch to the west and NW as a
new front drops SE into the CWA this afternoon. Expect the wind
speeds to be similar at 15 to around 20 kts across NW and NRN
sections of the CWA. Expect gusts exceeding 25 kts in these same
areas.

These winds will combine with very dry air near the SFC...with dewpts
remaining in the 20s to near 30. However...temps will warm above
normal...with highs this afternoon in the 60s to mid 70s. This will
result in min RH values dipping below 25 percent for most
areas...and as low as 15 percent for a few isolated areas across the
Ouachitas and Ozarks. Many areas will see Red Flag conditions
develop with these conditions coming together...with RH values
dropping at or below 25 percent...20 ft winds of 14 mph or
greater...and 10 hr fuel moisture levels of less than 10 percent. In
fact...all of AR has 10 hr fuel moisture levels of less than 8
percent...with some areas down as low as 5 percent across the NW.
The only areas that may not seen all criteria met for a Red Flag
Warning will be the SW quarter of the CWA due to winds at 20 ft
staying around 8-12 mph. However...both RH and fuel moisture levels
are low enough...and these same areas are placed in an Extreme
Drought. For this reason...will include all counties in the CWA in a
Red Flag warning for 16Z-00Z.

Fire weather concerns will persist into Tue...but expect cooler
temps to result in higher RH values during the afternoon hours. Even
so...very dry air will remain in place and no precip is expected.
Temps will be about 20 deg cooler...with highs back into the 40s and
50s.

LONG TERM...Wednesday Through Sunday

The extended forecast will mainly remain dry, with temperatures
around normal to above normal values. The elevated wildfire danger
will also continue across AR.

Wednesday will start with a surface high pressure system to the
south of AR, while an upper low pressure trough was over the eastern
US. An upper level northwest flow will be into the region, while a
south wind flow into AR will help warm temperatures on Wednesday.
Late Wednesday night to Thursday, the upper northwest flow will
allow a system and cold front to move through the region. Limited
moisture is seen, and the forecat will remain dry and with only some
clouds. Behind the cold front, a northwest wind and cooler air will
filter in over the area, and with cooler temperatures. Into Friday,
the upper low pressure trough deepens, and allows the surface high
pressure to settle in over the region. Temperatures on Friday will
be a bit below normal.

Over the weekend, the surface high pressure is forecast to settle
south of AR, and a south wind sets up again, while the upper pattern
will become more zonal from the west. GFS model forms a surface
system on Sunday, with some possible chance of rain in the forecast
late Saturday night to Sunday, while mainly in the east on Sunday as
the system moves east. The Euro is drier with little to no rain
forecast. Have taken a low end approach with a slight chance of rain
due to the uncertainty in model runs. Fine tuning will be needed as
we approach the weekend. Temperatures over the weekend will be
overall warmer than normal.

&&

.LZK Watches/Warnings/Advisories...
Red Flag Warning from 10 AM this morning to 6 PM CST this
evening FOR Arkansas-Baxter-Boone-Bradley-Calhoun-Clark-Cleburne-
Cleveland-Conway-Dallas-Desha-Drew-Faulkner-Fulton-Garland-Grant-
Hot Spring-Independence-Izard-Jackson-Jefferson-Johnson-Lincoln-
Logan-Lonoke-Marion-Monroe-Montgomery-Newton-Ouachita-Perry-Pike-
Polk-Pope-Prairie-Pulaski-Saline-Scott-Searcy-Sharp-Stone-Van
Buren-White-Woodruff-Yell.

&&

$$

Aviation...62


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