Area Forecast Discussion
Issued by NWS Wilmington, NC-- Remove Highlighting --
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FXUS62 KILM 201155
Area Forecast Discussion
National Weather Service Wilmington NC
755 AM EDT Thu Oct 20 2016
Warm and dry weather will continue through today. A strong cold
front will move through Friday, bringing significant cooling over
the weekend. A slight warming trend is expected Monday before a
secondary and dry cold front sweeps off the coast Monday evening.
High pressure will build down from the north behind cold front through
the middle of next week.
.NEAR TERM /THROUGH TONIGHT/...
As of 600 AM Thursday...One more full day of summer-like
conditions with low to mid 80s for highs with a few upper 80s well
inland away from the effects of the mesoscale sea breeze which
does progress inland, just not far enough. Stayed closer to the
slightly hier european mos guidance due to its superiority across
the other model mos guidances with this weather pattern. This also
includes the european mos for tonights lows which is also running
slightly hier than the other mos`s. The question for tonight is
the possibility of a low level jet that will keep it mixed to the
sfc. At this point, think the sfc based inversion that develops
after sunset will become just strong enough to prevent the mixing.
Therefore, have included patchy fog during the pre-dawn Fri hours.
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 330 AM Thursday...The cold frontal passage during Friday and
the influx of the coolest air of this autumn season will be the
story line for this short term period.
A change in the patter n aloft takes place during this period. The
upper ridge affecting the FA during the past week will succumb to an
amplifying s/w trof from the west which has its roots in the
Rockies. A northern stream s/w trof will hook up with main s/w trof
and result in a nearly full latitude trof that goes negatively
tilted by Saturday morning. This progressive flow sfc and aloft will
push the sfc cold front rather quickly across the FA with low chance
pops along it. The tstrm parameters are borderline...mainly the
further north you are located along the cold front with better
dynamics aloft. Thus will include isolated tsra for mainly the ILM
NC CWA and a small northern portion of the ILM SC CWA...elsewhere
will be shra. The time frame from west to east for the cfp and pcpn
to occur runs from 1000AM to off the ILM CWA Coast by 600 PM. Not
much wind ahead of the cold front but afterwards look for gusty NW
winds that run from late Fri thru Saturday. The tightened sfc pg
combined with excellent CAA as seen thru model partiaL thickness
schemes and just temps aloft...ie 850mb temps.
Winds will stay active thru Saturday due to a 1025+ mb modified
Canadian High pressure which its center drops to the Gulf Coast
States by daybreak Sun. Just not close enough for a good radiational
cooling night. As for temps, looking at 70s to lower 80s for
Friday`s highs ahead of the cold...with highs on Sat widespread 60s,
a drastic change from this past week! Saturday mornings lows expect
widespread mid to upper 40a,and Sunday`s lows in the lower 40s with
possible upper 30s inland depending if the FA`s winds can
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 300 AM Thursday...A deep N-NW flow will continue to usher
in cold and dry air through the latter half of the weekend as high
pressure remains sprawled across the southeast. Pcp water values
down near a quarter of an inch will rise slightly Sun night into
Mon as winds back to the W-SW as high pressure gets suppressed
south. A dry cold front will drop down from the north by late Mon
with high pressure building down from the north behind through mid
Temps a good 5 to 10 degrees below normal early Sun will rebound
late Sun into Mon back toward normal but will get knocked back
down with a reinforcing shot of cool and dry air behind front by
Tuesday. Overall expect plenty of October sunshine with overnight
lows below 50 most days and afternoon highs below 70 except Mon.
Latest guidance showing coldest temps below 40 just before
daybreak early Sunday morning. Temps near the beach will be
slightly warmer due to warmer ocean temps.
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --As of 12Z...Anticipate MVFR/IFR due to fog/low cigs again late
overnight into Friday morning. Otherwise expect VFR.
Conditions are already improving to VFR after widespread fog and
areas of low cigs created MVFR/IFR earlier this morning. Light
east-southeast winds will continue today with nearly clear skies.
Overnight, ideal radiational cooling conditions return, with the
development of fog and areas of low cigs anticipated to create
Extended Outlook...Potential for brief MVFR conditions in -SHRA
and clouds on Friday, especially late in the day. Otherwise,
-- End Changed Discussion --
NEAR TERM /THROUGH TONIGHT/...
As of 600 AM Thursday...Winds to start out variable around 5 kt.
Will identify the most dominate wind direction in lieu of going
variable. The expanding synoptic offshore low, NE of the Bahamas
by this evening, will result in a slight increase to the e to ne
winds later today backing to northerly tonight. With speeds only
increasing to 5 to 10 kt or around 10 kt. By late tonight...the
expanding low...will begin its turn toward the n or nne.
Significant seas will be at their minimum this morning followed by an
increasing 9 to 11 second period swell from the offshore low late
this aftn thru tonight. Seas around 2 ft this morning will build to
2 to 4 ft beginning late this aftn but majority of it occurring
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 330 AM Thursday...For Friday thru Friday Evening, the main
story will be the approach and passage of the cold front. Ahead of
the front winds will be wsw to wnw direction at 10 to occasionally
15 kt. The cfp will occur late this afternoon and early evening
with winds after the cfp increasing from the NW at 15 to 25 kt
with gust around 30 kt. Could see gusts approaching 35 kt late
Friday night or early Saturday during the height of the CAA
combined with the well tightened sfc pg. Winds will diminish-some
Saturday night as the sfc pg loosens a bit. With the center of the
high progged to be over the Gulf coast states by Sun morning,
winds across the area will remain active.
Significant seas will initially be influenced by the well offshore
Low with 2 to 4 foot or 3 to 5 foot seas affecting the local waters
and mainly in a 9 to 10 second period easterly swell.
After the cfp and thru the remaining short term period, the long
period swells will combat the building nw wind driven waves. By
Saturday thru saturday night, the 3 to 6 second short period wind
wave will finally dominate the local waters. Seas could reach 7 to 8
ft across the outer waters and just offshore from Cape Fear due to
the interaction of the incoming easterly swell and the increasing
offshore wind waves. But overall, looking at 3 to 6 ft on Saturday
subsiding to 2 to 5 ft...with the lower seas near shore.
LONG TERM /SUNDAY THROUGH MONDAY/...
As of 300 AM Thursday...Winds will lighten up and back to the
W-SW Sunday through Monday as high pressure shifts closer overhead
and weakens. Seas will subside through early Mon down to 2 to 3
ft. A dry frontal passage late Monday will bring W-SW winds 15 KT
or less Monday. Another surge of northerly winds overnight Mon
into early Tues may push seas up towards SCA thresholds on Tues.
As of 600 AM Thursday...A Coastal flood warning may be needed for
this afternoon`s high tide along the banks of the Lower Cape Fear
River from Wilmington southward to the river`s mouth. Water levels
are forecast to reach moderate flood thresholds, greater than or
equal to 6.7 ft MLLW during this afternoon`s high tide. Each
successive high tide will likely require either a coastal flood
warning or advisory. Of the 2 high tides per day, the afternoon`s
high tide will be the higher of the 2 through Saturday.
High Tide Times and the forecast water level for the downtown
1:55 PM on Thu Oct 20...7.0 ft MLLW.
2:22 AM on Fri Oct 21...6.6 ft MLLW.
2:57 PM on Fri Oct 21...7.0 ft MLLW.
3:23 AM on Sat Oct 22...6.1 ft MLLW.
3:56 PM on Sat Oct 22...6.5 ft MLLW.
Here are the flooding thresholds based on the downtown Wilmington
Gage on the Lower Cape Fear River...
Minor flooding......5.50 ft MLLW to 6.69 ft MLLW.
Moderate flooding...6.70 ft MLLW to 7.99 ft MLLW.
Major Flooding......8.00 ft MLLW
As of 600 AM Thursday...The ASOS at the Lumberton, NC airport
(KLBT) has no power and the emergency generator which had
maintained power since Hurricane Matthew has run out of fuel.
Observations and climate data from Lumberton will remain missing
until further notice.