Area Forecast Discussion
Issued by NWS Little Rock, AR
FXUS64 KLZK 200518 AAA
Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
1218 AM CDT WED JUL 20 2016
Updated to include the 06Z aviation discussion below...
TAFs continue to be in good shape, with all afternoon convection
weakening after sunset. Continued clear skies during the overnight
hours may lead to some patchy fog during the early morning hours.
At this point, have only tempo groups in to account for this. Some
afternoon convection will again be possible on Wednesday, with
best chances across northern and western Arkansas. Otherwise, VFR
conditions will persist.
PREV DISCUSSION...(ISSUED 247 PM CDT TUE JUL 19 2016)
Short Term...Tonight through Wednesday night
Model runs from this morning show little if appreciable change to
the overall pattern with generally hot and dry conditions continuing.
Some isolated convection has developed this afternoon but is expected
to dissipate quickly after sunset with the loss of daytime heating.
Water vapor imagery and model analysis reveal that the center of
sprawling anticyclone is currently over eastern Oklahoma. Feature is
not expected to move much through the period with temperatures
ticking up a degree or two each day. As such, will extend the heat
advisory for another day. The northwest counties will continue to be
excluded as heat indices remain below criteria.
Precipitation will be a minimum as ridge remains squarely in place.
Any convection will be diurnally driven and then isolated at best.
Long Term...Thursday night through Tuesday
The gist of it is...it will be miserably hot through the period,
enough to possibly warrant upgrading the ongoing heat advisory to an
excessive heat warning by Thursday.
The long of it...a broad upper ridge will remain anchored over the
far southern plains through the extended period which will keep
Arkansas hot and largely free of rain. Perhaps some relief will be
seen by early next week, but we must make it through this heatwave
first. Current forecasts are for highs in the 95-100 degree range
Thursday through the end of the period. This will coincide with
dewpoints in the 70s, yielding afternoon heat index values in the
100-110 range for large portions of the CWA. Some locations will
almost certainly exceed 110F Thursday, the warmest day of the long
term period. The question is, will there be enough areas that
reach/exceed 110F to warrant an upgrade to an excessive heat
warning. Right now it is too far out to make such a change but it is
something to keep an eye on.
By late in the weekend the upper ridge will flatten out as a
stronger disturbance moves across the northern United States. Upper
flow across the region does not change much but the weakening ridge
and lack of air mass change means that rain chances will be on the
uptick...albeit it slowly as it pertains to Sunday. More substantial
rain chances and slightly cooler temperatures, though still
warm, will be seen Monday and Tuesday.
Heat Advisory until 9 PM CDT Thursday FOR Arkansas-Baxter-