Scientific Forecaster Discussion
fxus64 kmeg 210205
Area forecast discussion
National Weather Service Memphis Tennessee
905 PM CDT Fri Sep 20 2019
Skies are partly cloudy across the mid-south this evening with
temperatures ranging from the mid 70s to lower 80s. Most of the
rain that was over portions of east Arkansas has left the region.
Dry weather should continue for the overnight hours. Will update
forecast to remove evening wording.
Previous discussion... /issued 349 PM CDT Fri Sep 20 2019/
the subtropical ridge continues to hold strong across much of the
mid-south this afternoon, providing warm and dry weather across
the region. However, west of the Mississippi River, tropical
moisture associated with the remnants of Imelda continue to lift
north across the arklatex. Precipitable water near 2 inches and a
modestly unstable air mass have resulted in scattered showers and
thunderstorms over eastern Arkansas into the MO bootheel. This
convection is forecast to dissipate around sunset with generally
dry conditions overnight.
The ridge is progged to strengthen this weekend, shifting
thunderstorm chances farther west by tomorrow. While there is a
non-zero potential for an isolated diurnal storm northeast AR, the
majority of the County Warning Area will remain hot and dry with highs again near
90f. Fortunately, dewpoints will be relatively low, maintaining
heat indices mainly 90f or lower. Similar conditions are
anticipated on Sunday, but we will see the next cold front
approach from the north Sunday night into Monday morning.
This front is expected to move south into the region on Monday,
eventually stalling across the mid-south and lingering through
midweek. Rain chances look to be the greatest on Monday (albeit
still only in the 20-30% range). Slight chance pops will prevail
Tuesday-Thursday, primarily in the vicinity of the boundary.
Temperatures will remain above normal behind the front as the
subtropical ridge retreats, trending back into the upper 80s and
lower 90s by Wednesday afternoon.
The synoptic pattern will shift late in the week, transitioning
from quasi-zonal flow aloft midweek to a building Southeast Ridge
as the weekend approaches. A strong trough will dig over the
western conus, but the ridge will steer this feature well north of
the area, limiting rain chances. By the weekend, the anomalously
strong ridge is progged to build well into the mid-south with
500mb heights around 594 dam, a good 2 Standard deviations above
climatology. This implies above normal temperatures and limited
rain chances next weekend.
VFR conditions should prevail at all sites for the next 24-30
hours. Expect light south winds tonight, increasing to 7-10kt