National Weather Service United States Department of Commerce

 


000
FXUS62 KILM 161910
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
310 PM EDT Wed Aug 16 2017

.SYNOPSIS...
Summertime heat and humidity will build across the area through
Friday. Showers and thunderstorms will be on the increase
during the weekend as a cold front approaches from the north.
This front may stall in close proximity early next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 300 PM Wednesday...With dewpoints in the mid 70`s and
temperatures in the upper 80`s to low 90`s, heat indices have
reached at or just above 100 degrees across much of the area
already. The Heat Advisory will remain in effect through this
afternoon for portions of the area.

Latest visible satellite illustrates quite the healthy cu field
across the area, while latest radar imagery only shows a few
showers and thunderstorms which have developed outside of the
forecast area. With latest guidance, do continue to expect
isolated to scattered showers and thunderstorms to develop this
afternoon into the early evening hours with the assistance of
the the afternoon sea breeze and piedmont trough. Any convection
that does develop will dissipate later tonight , with
conditions remaining fairly quiet overnight with overnight low
temperatures in the mid 70`s. Patchy areas of fog are possible
towards the morning hours.

On Thursday, upper level ridging will move into the Carolinas ahead
of the approaching cold front which is progged for later this week.
However, even with ridging in place, some available moisture, low
level convergence and lingering boundaries, have kept in slight
chance/chance pops for isolated to scattered convection. The heat
will be of discussion again as well, as higher dewpoints combined
with temperatures in the low to mid 90`s will likely allow heat
indices to reach 100 degrees, with some locations reaching
advisory criteria.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 300 PM Wednesday...High pressure will give way Thursday night
as a Piedmont trough develops over the Carolina`s on Friday ahead of
a cold front that will move into the central Carolinas by early
Saturday morning.

The deep 2+ inch precipitable water will continues its hold over the
area through this period. Convection is expected on Friday and
Friday night with the established trough and the approaching cold
front. With the 850 millibar temperatures hitting the 19 to 20C
range expect another hot day with possible heat advisories for
portions of the forecast area.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 300 PM Wednesday...Cold front stalled either just to our west
or even over western counties on Saturday while moderately strong
trough crosses through the Northeast and MidAtlantic. Thunderstorm
coverage should be elevated above the norm. Thunderstorm coverage
may also not show the normal diurnal decrease due to the presence of
the boundary. The higher concentration of storms will be over
northern zones where there also may be a small severe weather
threat. Temperatures will be running close to normal. The boundary
will show little movement into Sunday but height rises aloft will be
underway. Overall expect a downward trend in storm coverage and a
warmer afternoon.

Attention to Monday`s forecast continues to increase each day due to
the solar eclipse. Unfortunately there isn`t much different in the
way of thinking and even less fortunate the news isn`t great. True
the front will be weakening but convective signals in the models are
still suggesting ample moisture for considerable coverage of
thunderstorms that afternoon. The silver lining could be the rising
heights aloft, possibly capping thunderstorm formation until after
the eclipse or at least its peak. Even so all it takes is one
vigorous towering cumulus to ruin the view over a given location.

By Tuesday the front no longer appears in the models but a well
defined piedmont trough develops. Thunderstorms forming within this
boundary and moving east paired with seabreeze activity calls for
scattered POPs just about area-wide. By Wednesday some mid level
troughiness starts breaking into the area in association with a
large trough forming north of the Great Lakes. A continued moist
boundary layer paired with energetic NW flow likely means a
continuation of the unsettled weather.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
As of 18Z...Potential for brief MVFR in any heavy downpours this
afternoon/evening, as well as possible areas of MVFR with fog
across the area Thursday morning. Otherwise expect VFR.

Latest radar imagery remains fairly quiet at the terminals at
this time, but just outside of the forecast area, showers are
beginning to develop. Have kept VCTS/VCSH in the going forecast
for all terminals through this evening. Any heavy downpours
could create brief MVFR. Expect activity to deteriorate into
the overnight hours. Towards the morning hours, patchy areas of
fog may create MVFR, quickly dissipating after daybreak.
Overall winds will remain light and variable through the period.

Extended Outlook...A brief period of MVFR or lower conditions
can not be ruled out in isolated to scattered showers and
thunderstorms through Fri. The risk for flight restrictions due
to showers and thunderstorms will increase significantly on Sat
and Sun. Low stratus and some fog during the overnight and early
morning hours may result in flight restrictions as well each
day.

&&

.MARINE...
NEAR TERM /TONIGHT THROUGH THURSDAY/...
As of 300 PM Wednesday...Conditions will remain fairly quiet
across the waters as Hurricane Gert continues to move well away
from the waters, off to the northeast. Southwest winds up to 10
kts tonight will veer to the north and then northeast Thursday
morning, and back to the southeast by the afternoon hours. Winds
will remain around 5 to 10 kts. Seas will be around 2 to 3 ft.

SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 300 PM Wednesday...Winds will be from the south and will
veer to the southwest of Friday and Friday night ahead of a cold
front that will stall inland. This will increase the winds from
around 10 knots to 15 knots late Friday. Seas will respond by
increasing from around 2 to 3 feet to 3 to 4 feet late Friday
night.

LONG TERM /SATURDAY THROUGH MONDAY/...
As of 300 PM Wednesday...A front will be stalled over land over the
weekend and into Monday in a weakening state. This boundary will
serve a similar function to the piedmont trough normally seen during
the warm season and we should still see a fairly typical
southwesterly flow. Seas will run 2 to 4 ft for the most part,
highest offshore in the coast-parallel flow.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...Heat Advisory until 5 PM EDT this afternoon for SCZ017-023-024-
032-033-039-053>056.
NC...Heat Advisory until 5 PM EDT this afternoon for NCZ099-109.
MARINE...None.

&&

$$

NEAR TERM...SGL
SHORT TERM...HAWKINS
LONG TERM...MBB
AVIATION...SGL