Area Forecast Discussion
Issued by NWS Wilmington, NC-- Remove Highlighting --
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FXUS62 KILM 210532
Area Forecast Discussion
National Weather Service Wilmington NC
1232 AM EST Tue Feb 21 2017
Temperatures will remain unseasonably warm through much of the week.
High pressure will slowly build across the area through Tuesday,
shifting offshore Wednesday. A trough of low pressure will bring
increased cloudiness and some showers mid week. Near record warmth
will come Friday and Saturday with an increasing chance of
showers ahead of an approaching cold front Friday night into
Saturday. Cooler and drier high pressure will build in behind
the cold front Saturday night into early next week.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
As of 930 PM Monday...A big dirty upper ridge covers the
Southeastern United States this evening. Saturation throughout
the 400-250 mb layer (approximately 24000-36000 feet AGL) will
maintain plenty of cirrus through the night and into Tuesday.
Forecast lows are already on the upper end of the guidance
envelope for most locations so no updates are planned to
temperatures, still anticipated to fall into the mid 40s inland
with upper 40s to around 50 at the immediate coast.
Surface high pressure centered way up over Quebec extends a
ridge axis down the U.S. East Coast into the coastal Carolinas.
Sea level pressures should rise by up to 4 millibars across
northern North Carolina between 00z and 12z, while smaller
pressure rises are anticipated over South Carolina. This
tightening of the gradient will strengthen winds offshore and
also just above the partially decoupled boundary layer over
land. East to northeast surface winds around 5 mph should
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
As of 300 PM Monday...An upper ridge will continue to drift
eastward with its axis migrating offshore Tue afternoon and
evening. At the surface, high pressure centered across New
England and the northeastern states will ridge across the
eastern Carolinas. Low pressure along the Gulf coast Tue will
move to south Florida Wed night.
An onshore flow will allow marine stratocumulus to rotate inland and
these clouds should be most prevalent along the coast Tue afternoon.
A series of shortwave troughs, embedded in developing WNW flow will
bring a general increase in cloud cover, from W to E Tue night
through Wed night. There may be some late night fog Tue night as
onshore flow brings increasing dewpoints. The column does moisten
adequately enough to support the inclusion of a small risk for
showers, mainly Wed afternoon and eve and these look to be largely
diurnally driven. The shower risk Wed eve will shift offshore, but a
developing coastal trough may skirt the coast and will include a
small risk for showers along the coast overnight Wed. Perhaps
another round of fog or even stratus Wed night as onshore flow keeps
the low levels moist.
Cooler air at 850 mb on Tue and an onshore flow should keep temps
from rising above the mid and upper 60s along the more coastal
environs while the beaches may be stymied in the lower 60s. Further
inland, it should be at least a couple degrees warmer, around 70. A
good deal of clouds will be around Wed, but the column will be a
little warmer. Despite the onshore flow, we think lower to mid 70s
will be quite common away from the cooling impacts of the ocean. The
immediate coast should not rise out of the 60s. Lows will be in the
50s through the period, so it certainly will not feel like February.
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 300 PM Monday...Medium range guidance remains fairly
consistent on the events for the extended period. The flow will
show a little amplitude through the first half of the period as
a shortwave rides through the midwest and Ohio valleys with a
cold front at the surface. Models have trended lower with the
moisture with this system but we maintain some low chance pops
for Friday into the day Saturday. We also have slight chance
pops for Thursday via the sea breeze or pulse type convection.
Later Saturday through Monday should be mostly dry. Temperatures
remain well above climatology backing off a little Sunday and
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --As of 06Z...Expect VFR through the valid TAF period as high pressure
continues to build into the area. Mainly FEW/SCT cirrus expected
overnight into Tuesday as easterly winds remain around 5 kts. After
daybreak, northeast winds in the morning will return to easterly in
the afternoon, persisting around 5 to 10 kts. Cirrus will continue
to stream across the area as well, becoming BKN/OVC towards the end
of the period.
Extended Outlook... Patchy fog possible late Tuesday night. Isolated
showers late Wednesday through Thursday. Showers possible Saturday
with a cold front. Otherwise expect VFR.
-- End Changed Discussion --
NEAR TERM /THROUGH TONIGHT/...
As of 930 PM Monday...Pressures should rise across northern
North Carolina by around 4 millibars tonight, while only a 2
millibar pressure rise is expected over South Carolina. This
means we`ll have a steadily tightening pressure gradient, with
wind speeds increasing overnight to 12-16 knots with some
higher gusts offshore. Seas currently around 2 feet should begin
to build shortly in response the increasing winds, reaching 3-4
feet by late tonight, highest over the Cape Fear area waters.
The current forecast has all this well handled, and no changes
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 300 PM Monday...The center of surface high pressure will drift
south and be centered just offshore of the eastern Carolinas Wed,
migrating further eastward Wed night. Meantime, low pressure along
the Gulf Coast will move slowly southeast across the Gulf of Mexico
and should be situated across south Florida Wed night. NE winds Tue
morning will veer to easterly during Tue afternoon and SE Tue night.
An Ese to SE wind will prevail Wed and Wed night. The strongest
winds this period are expected Tue, up to 10 to 15 kt. A tightening
pressure gradient is expected to develop to our S Wed night. Seas
will be 2 to 4 ft Tue morning. Seas will trend a little lower Tue
afternoon and Tue night, 2 to 3 ft. Seas will be building to our S
Wed and Wed night and some of there higher seas will be working
their way into our waters late in the period.
LONG TERM /THURSDAY THROUGH SATURDAY/...
As of 300 PM Monday...Relatively light wind fields for most of
the day Thursday and even into Friday with a southeast flow of
ten knots or so. Winds finally pick up modestly Saturday ahead
and in the wake of a cold front on the order of 10-15 knots from
the southwest. Significant seas will be 1-3 feet Thursday into
Friday then increase considerably as a decent swell component
moves in from the southeast.