Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 241422
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
1022 AM EDT Sun Sep 24 2017

.SYNOPSIS...
High pressure will maintain warm and dry weather today.
Hurricane Maria is expected to move northward a couple of
hundred miles east of Cape Fear Monday through Wednesday.
Hazardous boating conditions, strong rip currents, and high surf
are all expected to develop. A cold front is expected to reach
the area Friday, bringing cooler weather for next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1020 AM Sunday...Maria is far off the GA/FL coast with a large
area of mid/upper ridging from the Great Lakes to New England and
portions of the Mid-Atlantic. High level moisture is increasing
across the area while the lower and middle levels remain dry. In
fact the low-level moisture axis will remain offshore for a while
longer given the trajectory. Overall, no POPs required with this
update, and only cosmetic changes made to the wind and temperatures.
High risk of rip currents continues along with the High Surf
Advisory. Water levels at the downtown gauge should fall just short
of minor coastal flood thresholds with the early afternoon high
tide.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 300 AM Sunday...All eyes will be focused on Hurricane
Maria, moving northward across the western Atlantic on Monday.
After making some precipitous shifts westward over the past
couple of days, this morning`s new model runs seem to have
stabilized on the idea of Maria moving northward along 73.5-74.0
degrees west longitude which would keep the center of the
hurricane about 220 miles east of Cape Fear at its closest
approach.

The upper air pattern on Monday will feature a closed 500 mb
high over the Great Lakes, the Bermuda Ridge well offshore, and
the rapidly weakening remnant upper low of former Hurricane Jose
in between. As Jose`s low dissipates, the two ridges will
bridge together. This large "wall" of high pressure should stop
Maria from accelerating out to the northeast as so many western
Atlantic storms do, and instead will cause a much slower north-
northwestward motion toward the Gulf Stream off the Carolina
coast.

Given the current track and intensity of Maria, we`re
forecasting N/NE winds to reach 15-25 mph with some 30 mph
gusts both Monday and Tuesday, highest along the coast. Moisture
should remain fairly limited this far west of the storm`s
center and we`re only forecasting 20-30 percent rain chances
near the coast Monday night into Tuesday, with virtually no
chance of rain for the I-95 counties. There are still some model
ensemble tracks that would give us much higher winds and rain
chances, and this situation continues to bear watching.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 300 PM Saturday...the big question will be how far
offshore will Maria stay. The latest global models continue to
show the center of Maria slowing down and staying just offshore
Cape Hatteras middle of next week. A trough of low pressure will
pick up Maria and carries it out to sea by late next week.

At the surface a cold front will move into the eastern
Carolinas and offshore by Friday. Cooler temperatures and drier
air will move into the region for Saturday. At this time only a
chance of showers is expected on the western fringe of Maria
during mid-week. With the best chances along the coast mainly
north of Little River, SC. There will be a slight chance of
precipitation late Thursday and Friday.

High temperatures Tuesday through Thursday will be in the
middle to upper 80s but as the front approaches maximum
temperatures fall into the lower 80s Friday and the upper 70s on
Saturday. Low temperatures are expected to be in the upper 60s
to around 70 Tuesday night and Wednesday night. Lows Friday are
expected to fall into the lower to middle 60s.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
As of 11Z...High pressure over the Great Lakes will maintain VFR
conditions through the day. Deep northeasterly winds dry out
quite a bit with height, so although there will be some
scattered cumulus clouds developing this afternoon with bases
around 4000 feet, a subsidence inversion should cap these clouds
by 6000 feet with no potential of deeper growth. Breezy
northeast winds should exceed 12 knots along the coast today,
but models do not suggest enough wind energy within the
5000-foot mixed layer to support significant gusts.

VFR conditions tonight could turn MVFR in the ILM vicinity late
as low stratus 1000-1500 feet AGL developing across far-eastern
North Carolina begins to slide southwestward.

Extended Outlook...MVFR/IFR in fog and stratus possible during
the morning hours Monday, particularly near ILM. Brief MVFR
conditions may develop at the coastal airports as Hurricane
Maria brings isolated showers Tue-Wed as it moves N, with its
center remaining well offshore. N winds may increase to 15 to
25 kt Monday Night through Wednesday.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 1020 AM Sunday...High pressure over the eastern Great
Lakes continues to ridge southward while Maria moves northward.
This pattern will maintain a northeasterly fetch that will
increase across the coastal waters while large swells also
increase in height and power through tonight. A Small Craft
Advisory will remain in effect through all of the waters. The
northeast fetch generated higher frequency wind waves will
create steep conditions as they superimpose with Maria`s
swells.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 300 AM Sunday...All eyes will be focused on Hurricane
Maria, moving northward across the western Atlantic on Monday.
After making some precipitous shifts westward over the past
couple of days, this morning`s new model runs seem to have
stabilized on the idea of Maria moving northward along 73.5-74.0
degrees west longitude which would keep the center of the
hurricane about 220 miles east of Cape Fear at its closest
approach. Assuming this track is correct and assuming the
model`s depiction of Maria`s wind field is correct, tropical
storm-force winds could remain just outside of our coastal
waters in the Cape Fear and Grand Strand areas. Northeasterly
winds should back around to the north on Tuesday with wind
speeds generally in the 20-30 knot range, highest near and north
of Cape Fear. It`s worth bearing mind that any significant
shift westward in Maria`s track would bring 35 knot winds into
the Cape Fear coastal waters.

What is completely certain is that exceptionally large swells
generated by Maria will move through the coastal waters Monday
through Tuesday. Wave heights of 6-9 feet south of Cape Fear and
8-12 feet north of Cape Fear are currently in our forecast.
Peak swell periods around 14 seconds imply extremely long wave
lengths. These waves will begin to feel bottom in fairly deep
water, and breaking waves will occur miles from shore in some
spots. Breakers should occur along the entire length of Frying
Pan Shoals even 30 miles from shore! It`s situations like these
that have earned us the name "Graveyard of the Atlantic."

LONG TERM /WEDNESDAY THROUGH THURSDAY/...
As of 300 PM Saturday...Winds will shift to the northwest on
Wednesday. Seas are expected to range from 5 to 9 feet north
Cape Fear and drop down to 4 to 6 feet south of Cape Fear on
Wednesday, subsiding on Thursday as Maria moves away from the
area.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...High Rip Current Risk through late tonight for SCZ054-056.
     High Surf Advisory until 8 PM EDT Monday for SCZ054-056.
NC...High Rip Current Risk through late tonight for NCZ106-108-110.
     High Surf Advisory until 8 PM EDT Monday for NCZ106-108-110.
MARINE...Small Craft Advisory until 6 PM EDT Wednesday for AMZ250-
     252-254-256.

&&

$$

NEAR TERM...SRP
SHORT TERM...TRA
LONG TERM...DRH
AVIATION...TRA



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