Area Forecast Discussion
Issued by NWS Wilmington, NC-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS62 KILM 051152
Area Forecast Discussion
National Weather Service Wilmington NC
652 AM EST Mon Dec 5 2016
Light rain will slowly wane through this afternoon as weak low
pressure moves away. A stronger system will move back into the
region tonight through Tuesday bringing more substantial
rainfall. Quiet and seasonable weather will occur mid-week
ahead of an arctic front which will cross offshore late
Thursday. Very cold temperatures will follow for Friday
and into the weekend.
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --As of 630 AM Monday...Low pressure is now northeast of the area,
with the coastal front having been pulled back off the mainland
and attm nearly thru the coastal waters. This evident with
latest W to NW winds behind the low across the ILM SC CWA at
the moment. The low will track well NE of the ILM NC CWA later
this morning, pulling the remaining inland portions of the
coastal front back offshore. Overrunning light to moderate rains
will come to an end from SW to NE later this morning thru early
afternoon. Radar indicates an axis of higher intensity rain
this morning extending from Timmonsville northeast across Latta
and Evergreen to White Lake. This will end up being the area of
hier rainfall totals for this round of pcpn.
For late this afternoon thru tonight, wedge of high pressure
with CAA at the sfc, will set up across the area. The cutoff
upper low over Mexico late this weekend, will get picked up by
the upper westerlies and track to the NE, opening up into a
potent s/w mid-level trof by late tonight as it and it`s
accompanying sfc low reaches the lower Mississippi Valley. The
offshore front from earlier will return northward as a warm
front...reaching the coast by tue daybreak. Expect overrunning
light to moderate rain to once again overspread the FA later
this evening and overnight.
Todays highs along the immediate coast will likely occur early
this morning with 60s. Otherwise, highs inland will occur
during the normal diurnal cycle. ie. afternoon. Tonights lows
will be a blend of mos guidance.
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.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 415 AM Monday...The potent mid-level s/w trof, over the
lower to mid Mississippi Valley and associated sfc low, will
lift to the NE reaching the Ohio River Valley by Tue afternoon.
The associated sfc low will fill in, with a new low pressure
system taking shape off the Southeast NC Coast. Ie. The Miller
Type B Scenario. An occluded front will exist between the 2 sfc
lows, that will dissipate as the coastal low becomes the
dominate low. Meanwhile, wedge of high pressure across the area
will remain strong due to the parent center of the sfc high
remaining over the NE states well into Tue afternoon. This will
result in a continued influx of cool air at the sfc with ILM
inland areas remaining on the cool side. Once again, the front
offshore will get pulled north as a warm front, and likely
straddle along the immediate coast. Will have a nice range of
temps depending how far inland the warmer temps push. At this
point, it could be a repeat of what occurred on Monday or to a
lesser degree since the source of cool air to sustain the wedge
will be stronger. The better dynamics aloft with this system as
a whole, will aid in the possibility of isolated thunder in the
vicinity of the coastal front. Instability either at the sfc or
elevated will be enough for possible mention of isolated
thunder. Overall, looking at categorical overrunning rains
early Tue morning thru early afternoon, ending from SW to NE.
QPF will be equal or slightly hier than what occurs during
Monday. The heaviest pcpn ends during Tuesday afternoon. A
lagging mid- level weak s/w trof could ignite -shra Tues
evening and for that left a chance POP.
For Wed and Wed night, flow aloft no longer taps the Gulf as
WSW flow becomes the mainstay. Weak high pressure builds across
the FA. RH Model time heights displays indicate decent drying
aloft which will enable skies to become mostly clear for Wed
thru Wed night. Temps for Wed will run at or slightly below
normal with neutral advection.
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 300 AM Monday...Arctic front to cross the Carolinas
Thursday, with very cold conditions following in its wake.
Guidance has slightly increased its moisture associated with
the FROPA, and will carry SCHC POP for northern zones late
Thursday as a few showers are possible. Increased column
saturation above 600mb suggests increased cloud cover, but very
dry air beneath this will prevent much more than a brief shower
or sprinkle with the FROPA. All precip will be of the liquid
variety however, it will be too warm for any snowflakes this
time around. However, it will certainly FEEL like winter
beginning Thursday night and persisting through Saturday as
temps plummet. 850mb temps have warmed slightly in new guidance
as the core of the cold air deflects to our north, but still
expect highs only in the 40s Fri/Sat with lows dropping well
into the 20s Friday night. Additionally, gusty winds Friday
will make apparent temps even colder than that. The Canadian
high pressure bringing this cold air will shift offshore
quickly late in the wknd allowing temps to recover to
seasonable values Sunday.
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --As of 12Z...A mixture of MVFR/IFR through the morning hours with
gradual improvement to VFR this afternoon. Expect conditions to
deteriorate again to MVFR/IFR tonight through the end of the valid
Latest radar imagery depicts showers moving across the area this
morning, tapering off already from west to east. Will continue with
low cigs, VCSH and the potential for areas of fog through later this
morning, with conditions expected to improve to VFR this afternoon.
Into tonight, rain chances return with conditions anticipated to
return to MVFR/IFR due to low cigs and areas of fog. Expect north-
northwesterly winds becoming north-northeasterly winds through the
TAF period, with sustained winds 5 to 10 kts and intermittent higher
Extended Outlook...Periods of MVFR/IFR likely through Tuesday night
due to rainfall and low cigs/reduced visibilities. MVFR developing
on Wednesday, with VFR returning on Thursday.
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-- Changed Discussion --NEAR TERM /THROUGH TONIGHT/...
As of 630 AM Monday...SCA thru this morning for all waters.
The coastal front this morning is now located near where the
coastal and offshore waters meet, ie. 20 nm out. Low pressure
moving along this front, is now northeast of the local waters,
and will track further away from the local waters later this
morning. The coastal front will get pulled into the offshore
waters later this morning before stalling this afternoon. The
south side of the coastal front is where you will find the
stronger SCA conditions, S to SW winds with speeds reaching 15
to 25 kt. Late today and tonight, when the front has pushed back
offshore, winds will become W to NW at 10 to 20 kt and further
back to the NE to ENE around 10 kt. High pressure wedging from
the north tonight will add 5 kt, making it around 15 kt with
some hier gusts overnight.
Significant seas this morning will have built to 4 to 7 ft in
the Cape Fear vicinity, and 3 to 6 ft elsewhere. Wind driven
waves at 3 to 6 seconds will dominate the seas thruout this
period. After the lows passage and offshore winds after the
coastal front bounces back offshore, seas will subside rather
quickly this afternoon into tonight before holding steady in the
2 to 4 ft range.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 415 AM Monday...SCA conditions may again be met across
all waters during Tue into Tue night.
Front offshore Monday Night, will get pulled back to the north,
across the Coastal waters and possibly onshore during the 1st
part of Tuesday. Low pressure is expected to develop off the
southeast NC Coast Tue afternoon and track northeast away from
the local waters by Tue evening. This will pull the front, now
a cold front, back off the coast and offshore Tue evening. Weak
high pressure ridge in late Tue night and prevail thru Wed
night. Peak winds will occur during Tuesday, slowly abating Tue
night and continuing this trend thruout Wednesday. Significant
seas will also peak during Tue and mainly dominated by short
period wind driven waves. Seas will likely quickly subside Tue
night thru Wed due to the lack of any long period ground swell
progged to affect the local waters. PCPN will be widespread on
Tue with mainly light to moderate rains with embedded
thunderstorms. A few of these embedded thunderstorms could mix
down the progged stronger winds aloft that could yield a SMW or
atleast Marine wx statements. Activity becomes isolated Tue
night with drier air and no pcpn for Wed.
LONG TERM /THURSDAY THROUGH FRIDAY/...
As of 300 AM Monday...Strong cold front will cross the waters
late Thursday producing SCA conditions into Friday. Winds ahead
of this front will increase and slowly veer to the west, before
shifting to the NW and becoming 20-25 kts, driving seas up to
4-6 ft despite the offshore winds. These winds will remain
strong through Friday, falling only slowly to 15-20 kts while
becoming more northerly Friday night. Wave heights will fall
quickly however as the offshore winds weaken, becoming 2-4 ft
late. An SCA will likely be needed for late Thursday and a good
portion of Friday.
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MARINE...Small Craft Advisory until 10 AM EST this morning for AMZ250-