Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 140634

Area Forecast Discussion
National Weather Service Wilmington NC
230 AM EDT Mon Aug 14 2017

A stalled frontal boundary will meander across the central to
eastern Carolinas today through midweek. Mid level ridging will
erode this front late in the week before another cold front
approaches next weekend.


As of 845 PM Sunday...A plethora of boundaries reside across
the ILM CWA with plenty of interactions still ongoing. Based on
latest 88D mosaics, the overall coverage of convection has
decreased across the Eastern Carolinas and will indicate this in
the latest update for this evening. Overall, will trend down
POPs to low or even slight chance respectively. With a
moisture-laden atmosphere, PWs above 2 inches, any convection
that does occur will primarily be heavy rain producers that
could result in localized flooding across prone locations such
as poorly drained and low lying areas. Have included patchy to
areas of fog, especially away from the immediate coast, during
the pre-dawn Mon hrs and extending up to a few hrs after
daybreak. Model guidance even suggests the possibility of dense
fog and low clouds, below 1k ft, in the vicinity and north of
the meandering frontal boundary. Low temps tonight in the mid
and upper 70s to around 80 along the immediate coast.

As of 300 PM Sunday...Convection this afternoon concentrated
along the sea breeze front near the coast and along a stalled
cold front oriented NE to SW west of LBT and FLO. Analysis of
morning data and latest guidance show a moderately unstable and
very moist atmosphere with severe weather unlikely but very
localized flooding from training storms a concern for the
remainder of the daylight and evening hours. High-Res data does
show some filling in between the above mentioned lines of
convection and this looks good given impending multiple boundry
interactions. However, this same guidance also shows activity
will mostly fade with the setting sun. For Monday, expect more
of the same with the stalled front wavering in the area and a
continued moist and moderately unstable airmass.

Temperatures will show little change from recently experienced.
Expect lows tonight in the mid to upper 70s, with highs Monday in
the mid to upper 80s. Elevated dewpoints will give us heat index
values of around 100F.


As of 300 PM Sunday...The pattern we have seen the past several
days will continue through the short term period. This consists
of a moisture rich southwest flow featuring persistent
precipitable water values over two inches. A weak boundary
wavering around the area (mostly inland) will provide an impetus
for convection along with the sea breeze and numerous outflow
boundaries and differential heating. The highest pops, likely
values, occur Tuesday afternoon with good chance and chance for
the other periods. Tuesday`s highs will be in the upper 80s to
near 90, depending on the convection with overnight lows pegged
in the middle 70s for the most part.


As of 300 PM Sunday...A return to summer heat and humidity occurs
late week as the mid-level trough finally gives way to SE ridging.
This ridge amplifies in response to a trough digging across the
west, and will drive increasing thicknesses, and hence temperatures,
into the Carolinas into next wknd. Despite this ridge expanding
from the Gulf Coast, heights locally may be relatively lowered
thanks to several weak impulses moving to the north in the zonal
flow across the Mid-Atlantic. These subtly steeper lapse rates
will combine with PWATs still above 2 inches, and strong
instability thanks to highs into the 90s to keep the chance for
showers and tstms in place each aftn/eve through late week,
although with coverage likely less than we have seen much of
August so far. By Saturday, a cold front will dig through the OH
VLY and then stall in the vicinity causing renewed good chances
for convection and slightly cooler temperatures. However, with
the ridge overhead this front may entirely dissipate by the end
of the period instead of lingering like many of our summer-time
fronts so far this season.


As of 06Z...As convection waned overnight, areas of fog
developed across the forecast area. Model guidance suggests
areas of dense fog and low clouds with IFR ceilings and vsbys.

With a frontal boundary running through the forecast area right
around the I-95 corridor, the threat for low clouds and fog,
possibly dense, will continue through the early morning hours. The
fog and low clouds should disperse by mid morning followed by
increasing chc of convection as atmosphere becomes more unstable
as temps rise. Looks like the convection will once again be
focused along sea breeze boundary and front as it shifts south
and east before moving north again later today.

Extended Outlook...There is a chance for MVFR/IFR ceilings and
visibility in showers and thunderstorms Tues through Thurs due
to a persistent stalled frontal boundary meandering across the
area. Each morning could see MVFR/IFR conditions from low
ceilings and reduced vsby from fog.


As of 845 PM Sunday...The stalled front will remain north and
inland from the coast overnight thru Mon. The resulting sfc
pressure pattern will produce a S to SW wind direction. The sfc
pg will remain rather loosened with resulting speeds around 10
kt or less. Significant seas overnight thru Monday will run 2
to 4 ft, with the 4 footers primarily off Cape Fear. The 4
footers will become more pronounced across all waters late Mon
and Mon night due to the closest approach of Gert, which will
pass well offshore from the ILM local waters.

As of 300 PM Sunday...High pressure over the western Atlantic
will keep winds southerly in the 10 kt range through the
period, with gusts up around 20 kts during the afternoon hours
and near convection. Seas will range right around 3 ft, give or
take a foot, through Monday.

As of 300 PM Sunday...Southwest winds of 10-15 knots will
persist throuigh the period. The speeds will lean moreso to
the lower end of the range. Significant seas will be 2-4 feet
with a general mix of a modest wind wave and swell component.

As of 300 PM Sunday...Broad high pressure offshore will exert
its influence across the waters through late week. This creates
SW winds through the period, with speeds only increasing above
10 kts on Friday in response to a cold front approaching from
the NW. The prolonged fetch around the offshore high pressure
will allow a 1- 2ft/9sec SE swell to persist through the end of
the week, but this will become masked by an amplifying 5 sec SW
wind wave, especially the latter half of the period. These 2
primary wave groups will create seas of 2-3 ft Wed/Thu, rising
to 3-4 ft on Friday.





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