Area Forecast Discussion
Issued by NWS Wilmington, NC-- Highlight Changed Discussion --
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FXUS62 KILM 051547
Area Forecast Discussion
National Weather Service Wilmington NC
Issued by National Weather Service Charleston SC
1047 AM EST Mon Dec 5 2016
Rain chances will decrease through the day as weak low pressure
moves away from the coast. 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 /UNTIL 6 PM THIS EVENING/...
Frontal wave is now located well to the northeast of Cape
Hatteras and will continue to pull away from the region. Some
lingering post-frontal isentropic assent is supporting
scattered showers along the coast, but this activity will
diminish over the next few hours. Temperatures have been held
down this morning by diabatic processes, but should recover some
this afternoon as rain ends. Opted to nudged highs down a few
degrees to account for current trends and the latest high
resolution temperature guidance. Visible satellite shows breaks
in the cloud canopy moving across the northwestern tier from
roughly Darlington, SC to Elizabethtown, NC. This should be
temporary as clouds are expected to increase again later this
afternoon as weak isentropic assent redevelops. Sky grids have
been updated to reflect this thinking.
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY 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 /WEDNESDAY 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 /16Z MONDAY THROUGH FRIDAY/...
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.
NEAR TERM /THROUGH TONIGHT/...
Buoy sea and wind reports indicate conditions have dropped below
Small Craft Advisory thresholds. Seas are still around 5 ft at
41108, but will continue to drop. Can not completely rule out a
few gusts to 25 kt east and northeast of Cape Fear for the next
1-2 hours, but do not think these will be frequent enough for
Winds and seas will increaes again tonight.
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.