Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 271956

Area Forecast Discussion
National Weather Service Wilmington NC
356 PM EDT Sun May 27 2018


A flood watch is in effect tonight into Monday. As Alberto
moves into the northeast Gulf of Mexico tonight, a deep plume of
tropical moisture will stream northward into the Carolinas,
bringing periods of heavy rain late tonight and Monday. A good
chance of showers and thunderstorms will continue through mid
week as a tropical feed of moisture is expected to continue as
Alberto moves north from the Gulf Coast to the Great Lakes by
Thursday. A drying trend is expected into next weekend.


As of 300 PM Sunday...Crisp photograph sequences taken from
the shiny new GOES-East is capturing exceptional detail of
Alberto slowly gaining momentum and gradual organization, at
present forecast to reach the FL panhandle Monday morning,

The visual data also confirms deep CB cores and over-shooting
cloud tops off the Georgia and South Carolina coasts, rising
north and west. This will bring periods of torrential rain
to NE SC and SE NC, and with already sopping and damp ground,
areas beneath intense rain-rates could lead to problem flooding
quickly in spots, and a Flash Flood Watch for all of NE SC and
SE NC is posted. 2-3 inch rain amounts expected tonight through
Monday day, with locally higher 4-5 inch amounts not to be ruled
out. Although stronger convergence will focus higher rain-rates
eventually inland, overnight into Monday, potential training of
heavy showers from the ocean, onshore, warrants a Flood Watch
for coastal zones as well.

Monday winds from the SSE may gust as high at 35-45 mph with
any convection due to increased low-level flow, and hodograph
analysis shows a non-zero chance of a brief tornado Monday
afternoon as an axis of 0-3 km helicity rises northward. The
strong surface convergence inland may prompt a few strong cells
capable of generating a meso-cyclone.


As of 300 PM Sunday...A deep tropical fetch will continue across the area
through the period. It appears, tracking the GFS, the more favored
times for heavy rain will be after midnight Tuesday and again late
Tuesday evening. These areas are matched with higher areas of mid
level vorticity and confidence is not overly high as these can
sometimes change dramatically with model cycles. With good rainfall
expected on Monday on top of the already soggy conditions I would
expect the Flash Flood Watch to be extended well into Tuesday.
Overnight lows will continue hovering in the lower 70s with highs
Tuesday in the lower to middle 80s highly dependent on the amount of
sun that peeks through.


As of 300 PM Sunday...Alberto will be tracking north from
Kentucky toward the Great Lakes Wed into Thurs. The continued
feed of tropical moisture streaming into the Carolinas between
Alberto and the Atlantic ridge will begin to diminish through
the period, but expect locally heavy rain possible still on Wed.
The pcp water values, well above normal, near 2.3 inches Wed
will diminish late Thurs into Fri as winds veer to a more
westerly direction in the low to mid levels as Alberto reaches
up near the Great Lakes. Even with the column drying out some, a
very moist atmosphere will remain into Saturday with a good
chance of showers each day. Overall, expect a very warm and
humid air mass in place with clouds and showers hanging on
through at least Thurs with increasing sunshine and less
widespread shower activity by Friday or Saturday. GFS shows
drier air wrapping around into the area next weekend which could
diminish the chance of showers further through the weekend.
Small diurnal ranges expected in temps with low 80s most days
and low 70s at night in a very warm and humid air mass.


As of 1725z...Deep south to southeast flow will ensure that a moist,
tropical airmass will remain in place through the period, with
isolated to scattered showers this afternoon mainly inland. The
marine layer will inhibit convection near the coast. Showers will
become more numerous after midnight, with IFR conditions becoming
predominate. Widespread convection is expected to increase across
the area from the south Monday morning, along with the potential for

Extended outlook...On Monday, IFR with periods of heavy rain and
potential LIFR in showers and some thunderstorms. Tue-Thu, tempo
MVFR/IFR in showers and thunderstorms. Drier air moves in on
Friday with decreasing potential for showers/tstms.


As of 345 PM Sunday...An increasingly dangerous marine period
as intensifying SE winds build seas, while torrential rain and
isolated TSTMS move in tonight and feed ashore through the day
Monday. Seas will build to 5-8 feet Monday, as 9-10 feet near
Frying Pan Shoals and edges of the Gulf Stream. Please know that
winds and seas will be even higher in and near TSTMS. The
intense rain-rates expected offshore, will sharply restrict
visibility measured in feet. Mariners of small craft should
remain in port this period.

As of 300 PM Sunday...A southerly flow of 10-15 and at times 15-20
knots will continue across the waters through about midday Tuesday.
Beyond that point speeds will diminish somewhat dropping firmly in
the lower range and tending toward the lower end of that range. A
small craft advisory will continue through about midday Tuesday via
some higher seas. Overall seas will be 5-7 feet for the advisory
time dropping to 2-4 feet by the end of the period.

As of 300 PM Sunday...Southerly winds less than 15 kts on Wed
will increase slightly as they veer to a more SW to W direction
Thurs into Fri. The off shore flow will allow seas up near 3 to
4 ft on Wed to diminish into Thurs, but a slight increase in
wind speeds will maintain seas between 2 and 4 ft with some 5
fters in the outer waters through Fri.


As of 3 PM Saturday...Approaching full moon is beginning to
pull water levels up a bit, and enough it seems, to breach the
threshold of minor flooding along the lower Cape Fear river. The
5.5 ft benchmark should be crossed by a few inches and a brief
advisory will be issued for downtown Wilmington, as water rises
out of the storm grates near Water St. and Market St, mainly
between 9-11 pm coincident with high tide.


SC...Flash Flood Watch from midnight EDT tonight through Monday
     afternoon for SCZ017-023-024-032-033-039-054>056-058-059.
     High Rip Current Risk from Monday morning through Monday
     evening for SCZ054-056.
NC...Flash Flood Watch from midnight EDT tonight through Monday
     afternoon for NCZ087-096-099-105>110.
     High Rip Current Risk from Monday morning through Monday
     evening for NCZ106-108-110.
     Coastal Flood Advisory from 9 PM to 11 PM EDT this evening for
MARINE...Small Craft Advisory from 8 PM this evening to noon EDT
     Tuesday for AMZ254-256.
     Small Craft Advisory from 2 AM Monday to noon EDT Tuesday for



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