Scientific Forecaster Discussion
fxus62 kcae 220026
Area forecast discussion
National Weather Service Columbia SC
826 PM EDT Sat Apr 21 2018
high pressure north of the region will remain in control through
Sunday morning. The synoptic situation will change through the
day Sunday as Atlantic and Gulf moisture overspreads the area.
Low pressure will move into the central Gulf states Sunday night
then slowly move eastward, finally crossing the forecast area
Tuesday night. This will result in widespread rainfall Sunday
evening through Tuesday. Unsettled weather could continue through
Near term /through tonight/...
high pressure will gradually shift eastward as low pressure
deepens and slowly pushes eastward over the Southern Plains.
Moisture will be on the increase from the south late tonight and
into early portions of Sunday morning. Latest models continue
to keep any rainfall south of the area through 12z, so have
maintained a dry forecast overnight. Clouds will increase mainly
over the csra and southern midlands, with overnight lows in the
mid 40s to around 50.
Short term /Sunday through Monday night/...
a closed low pressure system will slowly move east across the
lower MS River Valley Sunday through Sunday night then will lift
northward into the Tennessee/Ohio Valley on Tuesday. Its slow movement
can be contributed to high pressure over the northeast. Ahead of
the system moisture advection will increase on
Sunday...maximizing Monday into Monday night due to a strong low
level jet. Rain chances will increase Sunday afternoon from
south to north with models indicating significant rainfall
across the area through Monday night. Given the anticipated
frontal position and moist, weak lapse rate profiles over the
area, any thunderstorms affecting the csra and southern midlands
will likely be elevated and weak. Precipitable water values will be 1.25 to
1.5 inches Sunday through Monday...which is about 175 percent of
normal. Still expect rainfall amounts generally 2 to 3 inches
through Monday night with the potential for localized and river
flooding. The area of strong moisture transport will lift
northeast of the midlands on Tuesday with rainfall diminishing
during the day.
Temperatures will be in the upper 60s to around 70 Sunday afternoon.
Clouds and rain will temperatures in the upper 50s west to upper 60s
east on Monday. Breezy conditions can also be expected Monday.
Warmer reading in the 70s are forecast Tuesday as rain diminishes
and clouds decrease. Overnight lows will be above normal in the 50s
to lower 60s.
Long term /Tuesday through Saturday/...
mean upper trough to remain over the eastern third of the
country through the end of next week. Models still showing
timing inconsistencies. One short wave trough over the region
Wednesday will lift northeast followed by another short wave
trough crossing the region Thursday. The GFS has yet another
trough crossing the region late Friday while the European model (ecmwf) develops
an upper low over Texas. Each one of these short wave troughs
could push a cold front across the area. Have indicated low
chance pops Wednesday through Friday. Overnight lows will be
slightly above climo and with daytime highs near or slightly
Aviation /01z Sunday through Thursday/...
VFR conditions will continue through tonight with possible
restrictions developing Sunday morning.
High pressure will continue to dominate the pattern tonight
promoting dry weather. Moisture will increase across the area
late tonight and early Sunday as high pressure shifts east.
Ceilings are currently around 8kft, but clouds will continue to
increase from the south and ceilings will lower. MVFR ceilings
will be possible by late morning. A 25 kt low-level jet, cloud
cover, and some wind should keep fog from forming. Rain will
move in late in the period, reaching ags/dnl around 21z, and the
remaining terminals shortly thereafter. At this time, only
expect MVFR restrictions through 23/00z. Southeast winds will
increase Sunday, becoming gusty in the evening with the arrival
Extended aviation outlook...
chance of showers and associated restrictions Sunday night.
Widespread showers, possibly heavy, and associated restrictions
Monday/Monday night, with thunderstorms possible. Shower
chances and a possible thunderstorm and associated restrictions