Area Forecast Discussion Issued by NWS Wilmington, NC
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000
FXUS62 KILM 161449
AFDILM
Area Forecast Discussion
National Weather Service Wilmington NC
1049 AM EDT Mon Apr 16 2018
.SYNOPSIS...
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High pressure will settle south of the area and then move offshore
Wednesday. It will be dry this week with cool temperatures today
and Tuesday and then temperatures warming to above normal mid week.
A cold front will move across the area Thursday night, bringing
temperatures back to about normal late in the week and into the
weekend. A frontal system will approach from the west Sunday
bringing a chance of showers and thunderstorms.-- End Changed Discussion --
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.NEAR TERM /THROUGH TONIGHT/...
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As of 1000 AM Monday...One shortwave trough is exiting offshore
late this morning, taking the bulk of the clouds with it. However,
satellite already shows stratocumulus filling in as sunshine
gets to work on a chilly airmass and this trend will continue
into the afternoon.
CAA will keep 850 temps near 2c today. Some sunshine along with
westerly downslope flow will help to offset the CAA a bit to
produce temps in the mid 60s most places. Afternoon relative
humidity will be as low as 25 to 30 percent and winds will be
gusting to 25 to 30 mph. Wet ground from widespread significant
rain Sun and Sun night should prevent any fire weather concerns
today.
The column cools and dries out further tonight as another trough
pivots offshore, leaving a deep NW flow of dry and cool air. A
secondary push of CAA tonight will bring 850 temps down to -3 to
-4C. Looks like winds will be slow to diminish tonight, but do
look like they will drop off to 2 to 4 mph toward morning. We
are not expecting any freezing temps, mainly upper 30s to around
40. However, those traditionally cold spots will likely drop to
the mid 30s for up to 3 or 4 hours around daybreak. Rather warm
soil temps and dry low-levels in conjunction with the brevity
of near critical temps should prevent the formation of frost.
However, it can not be completely ruled out on a very isolated
basis, again where temps drop to the mid 30s.-- End Changed Discussion --
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.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 300 AM Monday...Mid-level trough across New England will
retreat as ridging begins to blossom across the Southeast downstream
of another upper low which will dive into the Great Lakes Thursday.
While this secondary feature will push a cold front towards the area
Wednesday night, the mid-week period will feature dry conditions
with warming temperatures as surface high pressure expands across FL
and then shifts eastward. While there may be periods of high level
cirrus as moisture streams overhead from the Pacific in fast flow,
the rest of the column is forecast to be quite dry as PWATs fall to
around 0.5 inches. This dry column combined with 850mb temps
climbing to +12 to +15C by Wednesday supports temps well above climo
the latter half of the period. Expect highs to soar into the 80s
away from the coast and sea breeze Wednesday, after much cooler
readings Tuesday around 70. The nocturnal mins will feature a
similar pattern, with near normal lows in the upper 40s Tuesday
night, dropping only to around 60 Wednesday night ahead of the next
cold front.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
Fair weather is expected through Saturday, despite the passage
of a cold front on Thursday as moisture is forecast to be
limited with the front. Cool high pressure will then control
area weather into Sunday when another frontal system approaching
from the west will bring a chance for showers and
thunderstorms. Max temperatures Thu will reach the upper 70s to
lower 80s with upper 60s to lower 70s expected Fri through Sun.
Mins in the upper 50s to lower 60s Wed night will cool to the
upper 40s to lower 50s for the remainder of the long term
period.
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.AVIATION /12Z MONDAY THROUGH FRIDAY/...
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As of 12Z...The front is now well offshore with high pressure
pouring into the state. Good cold air advection will keep winds
quite gusty today, particularly around mid morning. A VFR strato
cu ceiling is expected to form due to cold air aloft. The
ceiling will dissipate later today with diminishing winds
tonight.
Extended outlook...VFR.-- End Changed Discussion --
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.MARINE...
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NEAR TERM /THROUGH TONIGHT/...
As of 1000 AM Monday...The Gale Warning has been downgraded to a
Small Craft Advisory. W to SW winds will be strongest through
early afternoon, 25 to 30 kt before diminishing to 20 to 25 kt.
A secondary surge of dry and chilly air will keep the environment
well mixed tonight. Winds will veer to NW during the night and
remain in the 20 to 25 kt range before diminishing to 15 to 20
kt toward morning. Seas will also be highest through early
afternoon, up to 5 to 9 ft, subsiding to 4 to 7 ft this eve and
to 3 to 5 ft by tue morning.
We will issue a MWS for abnormally low water levels during the
afternoon low tide. Water levels will drop as low as minus 1 to
minus 1.5 ft MLLW before retracing higher after 3-4 pm.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 300 AM Monday...High pressure will expand across the FL Gulf
Coast before elongating E-W and shifting into the Atlantic Ocean
through mid-week. With the surface feature remaining well south of
the waters, the gradient will stay pinched so wind speeds will be
elevated at 15-20 kt from the west Tuesday, increasing to 20-25 kt
and backing to the SW late Wednesday and Wednesday night. This
increase is due to the sharpening of the gradient in response to
an approaching cold front late in the period, and will push
seas up to 4-6 ft, likely necessitating an SCA. Before that
occurs, seas are forecast to be 2-4 ft Tue/Wed as the offshore
wind component limits wave amplitude.
LONG TERM /THURSDAY THROUGH FRIDAY/...
As of 300 PM Sunday...High pressure will give way to a quick
moving front that will cross the waters late on Thursday.
Southwest winds 15 to 20 KT Thu will become W to NW after the
frontal passage Thu night before shifting to the N and
decreasing to 10 to 15 KT on Friday. There is a chance winds
could reach 25 KT Wed night and Thu and a Small Craft Advisory
may be required Wednesday night into Thursday. Seas 3 to 5 FT
Thu will subside to 2 to 3 FT by late Fri.-- End Changed Discussion --
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.ILM WATCHES/WARNINGS/ADVISORIES...
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SC...None.
NC...None.
MARINE...Small Craft Advisory until 6 AM EDT Tuesday for AMZ250-252-254-
256.-- End Changed Discussion --
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$$
NEAR TERM...RJD/RGZ
SHORT TERM...JDW
LONG TERM...RAN
AVIATION...DL