Area Forecast Discussion
Issued by NWS Memphis, TN
FXUS64 KMEG 280959
Area Forecast Discussion
National Weather Service Memphis TN
459 AM CDT Fri Apr 28 2017
Significantly more humid tropical air will spread north into the
Midsouth today, supplying the moisture necessary for thunderstorms
over the next three days. Primary forecast challenge remains
placement and timing of thunderstorms, and the associated flash
flood and severe weather risks.
Short range range convective-allowing models show an uptick in
thunderstorm chances as early as later this morning, along and
ahead of the northward-advancing surface warm front and aided by
Rain chances will increase this evening along and especially north
of the warm front, which should become more focused along the
MO/AR border. The models have trended further north with the
position of this front and associated heavy rainfall threat.
Expect heaviest overnight rains across southern MO, into central
IL. Still some potential for 2-3 inches over far northeast AR
during the late evening and early overnight, after the low level
jet ramps up and before the front lifts too far north.
All the Midsouth will remain in the warm sector on Saturday.
Isolated storms will be possible, mainly west of the MS River,
where midlevel heights are lower and falling more rapidly with
the approach of an upper low late in the afternoon.
The core of the upper low will lift into the TX panhandle by late
Saturday evening, with a downstream elevated warm moist conveyor
belt underlying strong upper level divergence from east TX into
western AR and MO. This system will translate eastward overnight,
with storms entering eastern AR prior to daybreak Sunday. A slow
eastward advancement will occur through the day. Locally heavy
rainfall will be possible, aided by precipitable water values near
2 inches and a tendency for storms to train in the slow moving
convective line. The flash flood watch may need to be extended
east of the MS River to account for Sunday`s rainfall.
Following the exit of the upper low Sunday evening, cooler and
dry weather will prevail Monday and Tuesday. Unsettled weather
returns Wednesday, associated with a northwest flow northern
branch shortwave digging into the lower and middle MS River
valley. Instability ahead of this system should be modest and
limited to areas south of I-40.
06Z TAF cycle
VFR conditions will continue during the overnight hours and for
much of Friday morning. Lower clouds will move into the region by
late Friday morning into Friday afternoon producing IFR ceilings.
By Friday evening, there will be some periods of VFR ceilings.
Thunderstorms will move into mainly northern sections of the
forecast area by Friday evening. Winds will be mainly from the
southeast at 5 to 10 knots overnight increasing to 10 to 15 knots
with higher gusts by Friday afternoon.
AR...Flash Flood Watch from this evening through Sunday evening for
MO...Flash Flood Watch from this evening through Sunday evening for
TN...Flash Flood Watch from this evening through Sunday evening for