Area Forecast Discussion
Issued by NWS Wilmington, NC-- Remove Highlighting --
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FXUS62 KILM 191436
Area Forecast Discussion
National Weather Service Wilmington NC
930 AM EST Thu Jan 19 2017
Weak high pressure today will move offshore tonight. A series of
mid level systems will bring unsettled conditions Friday through
Monday. The strongest system will move across Sunday and into
early Monday. High pressure will build back in toward the middle
of next week.
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --As of 930 AM Thursday...Though the mid 70s of yesterday are a thing
of the past today`s highs in the low to mid 60s are still a good 6-8
degrees above climatology. The low level cool advection has already
shut down and the mid level ridge overhead is building in amplitude.
The surface gradient is poorly defined making for very light winds
today. Some late day cirrus will spill in from the west possibly
making for a nice sunset. Forecast soundings from the WRF show that
low levels will begin to moisten towards 03Z. The 12Z WRF is also
slower with rain advecting in from the west late tonight, generally
keeping it all west of here. Will likely adjust the forecast
accordingly should other guidance come in supportive of this idea.
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.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 300 AM Thursday...The main area of low pressure will be moving
across the Midwest on Fri. Its trailing frontal system will advance
into the Carolinas. A mid-level shortwave trough is expected to
spawn weak low pressure offshore along the front Fri. The low is
expected to then move away, but the front should stay in fairly
close proximity. Thus, the forecast remains unsettled and is
trending wetter than this time Wed. The initial surge of showers
should become more diffuse as they travel from SW to NE. The highest
risk for measurable rainfall will be across the I-95 corridor. Will
show POPs trending lower as the shortwave energy lifts out with
offshore showers becoming dominate. There is a potential for one to
possibly two tenths of an inch of rainfall late tonight into Fri. We
may catch 12 hours or so where POPs are below threshold as the front
gets knocked back by the departing coastal low Fri night. However,
by Sat, isentropic lift and a series of upper level troughs will
bring showers back into the forecast well ahead of a strong area of
low pressure across the Southern Plains. This time the rainfall will
be more significant. Given mixed layer CAPE values rise to around
500 J/kg Sat afternoon, will introduce a slight chance for
thunderstorms which may persist into Sat night.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 300 AM Thursday...Deep cyclone with complex frontal
structure will affect the area Sunday and into the day Monday.
Initially mid level low pressure will be moving across the Tennessee
Valley with a cold front extending southward into the Gulf of Mexico
and a warm front extending eastward bisecting the Carolinas. Sunday
will see warm sector showers and thunderstorms somewhat disorganized
in nature. The more organized convective line moves across late
Sunday night into Monday morning. The last few cycles of the
operational GFS show a kind of split in the line as the warm
conveyer belt shunts the best moisture off to the east and
northwest via a strong dry slot. This could reduce QPF amounts
and severe potential, but good coverage of showers and isolated
thunderstorms is expected nonetheless. Beyond this, a zonal
pattern develops at the mid levels which turns more
southwesterly in time with another front approaching very late.
No changes to the temperature forecast which are of course warm
early on dropping back just a little Tuesday and Wednesday.
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
As of 12Z...High pressure will move across the Mid-Atlantic
states and offshore tonight. Light northeast to east surface
winds and VFR conditions are expected today. Atlantic moisture
will return tonight as veering southeasterly winds develop just
above the surface. This could bring in a layer of 3000-4500 ft
AGL stratocumulus between 0200Z-0400Z. Deeper moisture aloft
could bring some light rain into the Florence and Lumberton area
just before daybreak Friday.
Extended Outlook...IFR ceilings and vsbys are possible, especially
inland Fri night into Sat morning as a warm front and rainfall event
develops. IFR conditions will again be possible late Sunday into
Monday as a strong low pressure system impacts the area.
-- Changed Discussion --NEAR TERM /THROUGH TONIGHT/...
As of 930 AM Thursday...High pressure today will move offshore
tonight. NE winds 10 to 15 kt today will veer to easterly this eve
and then SE overnight. Wind speeds tonight will be 10 kt or less.
Seas of 2 to 3 ft this morning will subside to 2 ft or less this
afternoon and tonight.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 300 AM Thursday...A warm front will move into the area from
the SW on Fri. A mid-level shortwave should spawn a weak area of low
pressure along this front offshore. The weak low will move away, but
the front should stall/waver in close proximity Sat and Sat night as
strong low pressure begins to advance east from the Southern Plains.
Expect southerly winds to hold on across the waters through the
period. At this time, they are not expected to exceed 10 to 15 kt.
Seas will be 2 to 3 ft. Much higher winds and seas are expected late
in the weekend when Small Craft Advisory conditions are expected. As
dewpoints approach a critical window Sat, there may be an
opportunity for sea fog to develop.
LONG TERM /SUNDAY THROUGH MONDAY/...
As of 300 AM Thursday...Southerly winds will pick up steam during the
day Sunday as a potent storm system moves closer to the area. Speeds
increase from 10-15 knots early to a healthy 15-20 knots late in the
evening. The strongest winds move across early Monday morning
reaching a maximum of 20-25 knots. A southwesterly flow develops
later Monday behind the front which is essentially a slight wind
direction shift. Speeds decrease to 15-20 knots. Significant seas
will build as well with small craft conditions developing by midday
Sunday and persisting through the remainder of the period. Could see
some 8-10 footers at maximum height across the outer waters early
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