Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Memphis Tennessee
1038 am CDT Sat Aug 30 2014
Discussion...water vapor satellite/WSR-88D VAD wind profiles
place an upper level low over western Iowa with a longwave trough
extending south from the upper Midwest back through the central and
Southern Plains this morning. A warm conveyor belt of moisture
from the Gulf of Mexico is present across the lower Mississippi
Valley...resulting in high precipitable water values across the
region and increasing surface dewpoints into the lower 70s.
Overall rainfall amounts have been relatively light this morning.
However...showers and thunderstorms are anticipated to increase in
coverage as a shortwave trough over central Mississippi moves up
into the middle south this afternoon into early evening. Will make
some adjustments to temperatures to account for current trends.
Otherwise...remainder of forecast overall is in good shape at this
time for this afternoon.
Updated grids will be available shortly.
Previous discussion... /issued 629 am CDT Sat Aug 30 2014/
Updated for the 12z aviation discussion
Previous discussion... /issued 417 am CDT Sat Aug 30 2014/
plenty of showers and thunderstorms on the radar tonight mainly to
our south and west...but coverage across the midsouth is expected
to increase over the next several hours. Temperatures at 4 am are
in the middle 70s under cloudy skies. Only another degree or two of
cooling is expected before sunrise.
Guidance is a little more bullish on the ridging during the
upcoming work week resulting in slightly warmer temperatures...but
overall no significant changes in this forecast update.
Still a little concerned about the potential for heavy rain over
the next 24 to 48 hours. Model precipitable water values are over
2.25 inches...up to 2.55 inches by this afternoon. Rainfall totals
yesterday help substantiate the heavy rainfall concerns. Portions
of east Arkansas received well over two inches of accumulation.
Hodographs are fairly straight today through Sunday morning
indicating the potential for training showers and thunderstorms is
high. Will add the possibility of localized flooding issues to the
severe weather potential statement. Rainfall totals through the weekend will likely exceed 1.25
inches across all of the midsouth with localized amounts over 3
inches likely. Conditions should begin to improve Sunday afternoon
with mostly dry conditions on Labor Day. Rain...clouds and
thunderstorms will keep temperatures mild today and tomorrow...but
warmer readings will return Monday. No severe thunderstorms are
Guidance still looks a bit too warm next week. As stated
earlier...guidance is a bit more bullish building in the ridge
next week. Bumped temperatures up slightly....but still leaning
towards a slightly cooler solution. For now...advertising high
temperatures slightly above normal for most of next week...but
below the middle 90s in guidance output.
12z taf cycle
VFR conditions will continue through most of the day with ceilings
and visibilities lowering to MVFR levels this evening. Showers and
thunderstorms will move across the forecast area during much of
the forecast period. Winds will be mainly light and mainly from the
south this morning and slowly increase to 5 to 10 knots this evening.