Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus62 kilm 281436 
afdilm

Area forecast discussion
National Weather Service Wilmington NC
issued by National Weather Service Charleston SC
1036 am EDT Fri Apr 28 2017

Synopsis...
expect high pressure to extend across the area from offshore
through Sunday. Expect warm temperatures and isolated sea breeze
convection, mainly on Sunday. The next cold front will bring a
chance of showers and thunderstorms late Monday into early
Tuesday. High pressure will follow for the mid-week period. Low
pressure system may impact the region during Thursday with a
soaking rain.

&&

Near term /through tonight/...
for the mid-morning update... retreating low-level clouds are
mitigating the potential for shower development this morning,
and several high-res model suites are not impressed with early
shower or convective initiation, so pops have been lowered
slightly for the next few hours. Isolated afternoon convection
due to the seabreeze cannot be entirely ruled out so will blend
into the previous pops forecast. Minor near-term adjustments to
hourly surface parameters have been made based on observations,
but previous forecast appears largely on track. The Bermuda high
stretching into the forecast area will promote humid conditions
with above average temperatures, especially inland. Expect high
temperatures in the mid to upper 80s away from the coast.

&&

Short term /Saturday through Saturday night/...
as of 330 am Friday...high pressure and ridging aloft and at the
sfc will be the primary drivers affecting sensible weather
across the ilm County Warning Area. Closed high with heights of 590+ dam will
anchor offshore and east of the Carolinas during this period.
The center of the sfc high will basically park underneath the
upper high offshore with ridging extending westward and onshore
in the vicinity of Cape Romain on Sat, and onshore and inland in
the vicinity of Cape Fear Sunday. A semi-tightened sfc pg will
occur across the forecast area thruout this period keeping S to SW winds
active, even during the evening and overnight. The sea breeze
each aftn and evening will further enhance the S winds. An
active low level jet will keep winds busy during the overnight,
preventing any widespread fog development, but enough moisture
in the low levels may result in low stratus or stratus fractus
each early morning.

The subsidence from the ridging will keep pops in check on
Saturday but could see isolated sea breeze induced convection
during Sunday with the subsidence weakening slightly. Daily high
temperatures for Saturday will run in the 80s to lower 90s
inland, and for Sunday mainly widespread 80s due to winds having
become more southerly thruout enabling some marine influence to
extend well inland. Balmy nights can be expected with upper 60s
to lower 70s.

&&

Long term /Sunday through Thursday/...
as of 300 PM Thursday...surface and mid level ridge will
weaken and drift east Mon, allowing a cold front to approach
from the west. Low pressure and associated strong dynamics and
upper level support will be well dislocated from the Carolinas
as a cold front moves across the area Mon night. This suggests
convection weakening as it moves into the eastern Carolinas.
Current timing brings the likelihood for showers and
thunderstorms later Mon and Mon night.

As the front moves off the coast Tue morning, high pressure
along the Gulf Coast will slide east and then offshore to our S
during Wed. This should bring a dry period. Deep low pressure
will move out of the mid south and Gulf Coast states Wed,
lifting slowly to the NE. Its associated cold front will move
into the southeast states Thu-Thu night, bringing the risk for
robust thunderstorms.

&&

Aviation /14z Friday through Tuesday/...
as of 12z Friday...IFR/MVFR conditions this morning especially
across the coastal terminals due to low level stratus and fog.
Should dissipate by mid to late morning leaving diurnally driven
cu possible, becoming enhanced along the sea breeze boundary.
Sfc dewpoints in the 70s have pushed onshore mainly affecting
the coastal counties and resulting in 1500 to 2500 cape avbl
for convection this morning into the aftn. Have included thunderstorms in the vicinity
to highlight it's possibility across the coastal terminals.
Sea breeze will enhance southerly wind speeds across the
coastal terms by midday and continue thru this evening. Low
level S to south-southwest jet to develop during the pre-dawn Sat hrs and
will help to keep sfc fog from becoming widespread or dense.
However, a low level stratus deck will likely occur again.

Extended outlook...VFR through Sunday with brief MVFR condition
possible across the coastal terms due to spotty sea breeze
convection. Periods of IFR/MVFR conditions possible in
showers and thunderstorms late Monday into early Tuesday.

&&

Marine...
near term /through tonight/...
as of 330 am Friday...southwesterly flow will be King with a
large area of high pressure across much of the western Atlantic
centered well east of Bermuda. With such a broad swath of flow
coming across the Bahamas and into the southeast a swell
component will be able to coexist with the relative small wind
waves. For the most part this will yield a forecast of 2 to 4 ft
for all zones.

Short term /Saturday through Sunday night/...
as of 330 am Friday...sfc high pressure parked offshore from the
Carolinas will extend westward and onshore in the vicinity of
Cape Romain Saturday, and onshore vicinity of Cape Fear Sunday.
Winds Saturday will run S to SW at 10-15 kt, with the SW
direction mainly occurring over the waters from Cape Fear
northward. For Sunday, the slight deviation with the sfc ridging
will produce south winds thruout with speeds 10 to 15 kt
initially, increasing to 15 to 20 kt as the sfc pg further
tightens as an eastward moving cold front tracks into the
western Carolinas late Sunday night. The sea breeze each day
will result in winds gusting around 20 kt near shore.
Significant seas will run 2 to 4 ft, choppy nearshore each aftn
and early evening due to the sea breeze influence. Seas will
build Sunday night reaching 3 to 5 ft by daybreak Mon. A
southeast to south-southeast pseudo swell at 5 to 7 second periods will be the
primary driver for significant seas this period.

Long term /Monday through Tuesday/...
as of 300 PM Thursday...western Atlantic high pressure will
bring increasing S winds ahead of a cold front. South winds 15
to 20 kt early Mon will increase late Mon and Mon night, up to
20 to 25 kt with seas 3 to 5 ft at the start building to 5 to 8
ft. In the wake of the cold frontal passage early Tue, offshore
winds will slowly diminish. The offshore trajectories will knock
seas down and we should drop below Small Craft Advisory levels
by Tue eve.

&&

Ilm watches/warnings/advisories...
SC...none.
NC...none.
Marine...none.

&&

$$
Synopsis...

National Weather Service Glossary of Abbreviations