Area NWS Forecast Discussion
000
FXUS62 KILM 181831
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
Issued by National Weather Service Charleston SC
231 PM EDT Tue Sep 18 2018

.SYNOPSIS...
A front will cross the Carolinas today, exiting off the coast
by Wednesday morning. This will usher much drier air into the
region, with no significant precipitation expected this week as
high pressure builds in from the north. Lingering effects of
Florence will be felt for days to come as dangerous river
flooding continues.

&&

.NEAR TERM /THROUGH TONIGHT/...
Early this afternoon: So far, showers along the incoming surface
trough/front have remained isolated at best. Satellite imagery
shows the cumulus field ahead of this feature is quite
unimpressive which matches up well with MLCAPE values in the
500-1000 J/kg. Updated rain chances to match radar trends, but
didn`t make any significant changes. The best chances are still
expected along the coast later this afternoon.

Tonight: As the surface trough/front shifts offshore this
evening, the focus for additional convection will be across the
adjacent coastal waters. Then by late tonight the forecast
becomes rain free everywhere and winds will turn more northerly
with time as drier air begins to filter in.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 300 AM Tuesday...The start to a dry period across the
Carolinas, with a change in air mass, as high pressure builds
in behind an exiting front Wed into Thurs. At the same time the
mid to upper ridge will migrate across the Southeast taking up
residence nearly overhead by Thurs night. A deep northerly flow
will advect dry air into the area with pcp water values down
less than 1.5 inches to start the day on Wed. These values will
decrease further to less than 1.25 inches through the period as
sfc high pressure continues to extend down from the north as it
migrates eastward toward the coast. Overall expect dry and warm
weather during the day with temps in the mid 80s both days, but
a couple of degrees less on Thurs. Overnight lows will feel a
bit cooler as lower dewpoint air will allow for greater diurnal
swings with temps dropping below 70 many places inland Wed night
and down into the mid 60s Thurs night.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 300 PM Monday...Mid-level high pressure will dominate the
upper levels through Sunday. The 500 mb ridge Will shift south of the
area and a weak front will be along the Virginia-North Carolina
border on Monday. The precipitable waters are expected to be at or
below 1.25" through Sunday. What this means is the chances for
precipitation will be low with a slight increase on Monday afternoon.

High temperature are expected to be in the middle to upper 80s
through the period. With lows in the upper 60s inland to the lower
70s at the coast.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
The main concern through the afternoon is the potential for
thunderstorms. Current thinking is that inland coverage will be
isolated, with scattered thunderstorms along the coast. Have
updated the forecast to include VCTS only at KCRE and KILM in
the 21-00z window. Still not confident in direct impacts. Then
overnight, the front will push southward and drier air will work
in from the north. Guidance is a bit mixed, showing some
potential for light fog, but with the drier air moving in it
seems reasonable to keep fog out of the forecast for now except
at KLBT.

Extended Outlook...Predominately VFR throughout the extended
period due to ridging aloft and high pressure at the sfc keeping
a lid on convection development.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 300 AM Tuesday...Ahead of the sfc frontal boundary, the
sfc pg will remain tightened with the sfc pressure pattern
yielding S-SW winds 10 to 20 kt to start, veering to the WSW-WNW
as the front pushes across the waters this aftn and early
evening. And finally, further veering to the NW-NE after the CFP
later tonight and pre- dawn Wed hours. Speeds at the end of the
period will run 10 to 15 kt. Models may be under-estimating the
dry surge after the CFP but for now will keep it at 15 kt
speeds. Significant seas will be initialized in the 3 to 4 foot
range with occasional 5 footers. As winds veer and become
partially to mostly offshore later tonight, the seas will see a
decline by at least a foot come daybreak Wed. Dominant periods
will run 6 to 8 seconds with an underlying small SE groundswell
at 11 to 13 second periods.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 300 PM Monday...A sfc front will be crossing the waters
Wed morning. NW winds behind the front will veer to N on Wed
and will continue to shift around to the NE by Thurs and more
easterly by Thurs night as high pressure builds down into the
waters from the north and then migrates eastward. Winds 10 kts
or less Wed morning will increase to 10 to 15 kts Wed night into
Thurs. Seas on a downward trend to 2 to 3 ft through Wed will
jump up a bit Wed night into Thurs, to 3 to 4 ft.

LONG TERM /FRIDAY THROUGH SATURDAY/...
As of 300 PM Monday...High pressure will be over the coastal
waters through the period. Winds will shift to the east and
weaken to 5 to 10 knots on Fri into Sat. Seas will range
generally in the 2 to 3 foot range.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...Beach Hazards Statement until 8 PM EDT this evening for SCZ054-
     056.
NC...Beach Hazards Statement until 8 PM EDT this evening for NCZ106-
     108.
MARINE...None.

&&

$$

NEAR TERM...BSH
SHORT TERM...RGZ
LONG TERM...RH
AVIATION...BSH
MARINE...

NWS ILM Office Area Forecast Discussion