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000
FXUS62 KILM 271113
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
713 AM EDT Thu Jul 27 2017

.SYNOPSIS...
Isolated showers and thunderstorms Thursday will become
more numerous Friday into Saturday ahead of an unseasonably
strong cold front. Some of these storms could reach strong to
severe levels Fri aftn thru early Sat. Drier and cooler air,
relatively speaking, is expected to push across the area in the
wake of the cold frontal passage late Sat and continue thru
early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 300 AM Thursday...The local area will remain in
subsidence and dry air through today although the NE to
E flow will come back around to the SE to S by this afternoon.
Temperatures were down near 70 early this morning in a drier and
relatively cooler air mass, but there will be a gradual
moisture return bringing dewpoint temps up a few degrees
tonight. Shallow moisture provided some patchy fog and low
stratus in places, but this will dissipate allowing for plenty
of sunshine through the day today. The developing southerly
winds may bring some of the moisture from convection associated
with lingering front/low over Fl/GA this afternoon. Have
included a slight chc of shwrs/tstms over the Georgetown area to
account for this slight moisture return. Overall expect temps
to return into the mid to upper 80s after a below normal start
to the day.

Mid to upper ridge extending in from the west will get
squeezed out as trough digs down from the north late today
through tonight and weakening low to the south moves off to the
north to northeast. This lingering low pressure to the south
will weaken and move north to northeast through early Fri. This
should produce some shwrs/tstms over the waters by Fri morning
and some of these showers will affect the coast. Convection
associated with shortwaves rotating around mid to upper trough
should remain northwest of area through today but will include
increasing chc of convection reaching into the area by Fri
morning. Pcp water values as low as 1.2 inches today will
increase up near 1.6 inches by Fri morning but just to the south
and north values will be up to near 2 inches. The moisture
return will bring temps back up into the mid 70s for low temps
tonight.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 400 AM Thursday...An active wx period will highlight
this time period. Already under the influence of an upper trof
at the start of this period, it`s amplification is progged to
increase as a vigorous mid-level s/w trof dropping southeast
from the Great Lakes, reaches the Mid-atlantic states early Sat.
Models amazingly even agree in taking this open s/w and closing
it off over the Mid-Atlantic states thru Sun morning. All of
this activity aloft is quite unusual for this time of the year
when the area is usually under the influence of Bermuda High
pressure sfc and aloft with subtle flow aloft.

At the sfc, Friday will see convection fire up along a
pre-frontal trof across the central Carolinas and push to the
ILM CWA during the aftn and evening. By Friday night, will see
sfc low really start to take shape and in association of the
vigorous mid-level s/w trof dropping toward the Mid-atlantic
states. This 1010mb low initially will strengthen to at or
below 1000mb by Sat morning over the DELMARVA area. It`s
associated cold front will be pushing southeast across the FA
Sat aftn and clearing the ILM CWA Coast during Sat evening.
Convection ahead and along the cold front Fri evening thru Sat
will have plenty of dynamics to work with that will result in
strong to severe thunderstorms likely. SPC already has a Slight
Risk across the FA.

As for temps, maintained a blend of model guidance thru the
period. Looking at a decreasing trend to both highs and lows
from Friday thru Sunday morning.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 300 PM Wednesday...Primary weather features this period
include an unseasonably amplified upper trough, followed by
Canadian high pressure which may bring a brief feel of very
early Fall, as dewpoints dip below normal for the season. A
surface trough inland Saturday will move offshore Saturday
night, as relatively strong high pressure from Canada barges
in from the NW in earnest early Sunday. The high will drop
dewpoints deep into the 60s Sunday, removing the muggy edge
well into the next week, as the high remains anchored over
the mid- ATLC region. The best rain chances are Saturday,
before mid-level drying and lowering dewpoints inhibit
convection. NE flow in the low-levels may bring in bouts of
oceanic cu and, in conjunction with the Canadian high, will
keep maximum temperatures below normal from Sunday onward.
This accompanied by small rain chances, mainly by the coast.
It`s possible a few storms early Saturday could be capable of
strong gusts.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
As of 12Z...Mainly VFR conditions during this 24 hr stretch.
Only exception will be possible MVFR conditions from BR during
the 08z-12z time frame Fri morning.

Upper level cloudiness will push across the FA thruout this
period. There is a mid-level cloud deck from EDE to CLT that is
making some progress southeastward. Will include short term bkn
deck in the 6.0k to 7.0k foot height in the FLO and LBT TAFS
but hold off with the coastal terminals. This deck likely to
scour out by the time it reaches these terminals. Diurnal Cu
will sprout up in the 2.5k to 4.5k foot level later this morning
and aftn however will keep it FEW/SCT. Light NE-E winds around
5 kt will start the day. The center of the sfc high will push
off the NC Coast this aftn. The sfc pressure pattern becomes
conducive for southerly winds 5 to 10 kt except SE-SSE around 10
kt for the coastal terminals. Depending how much heating will
determine the strength of the sea breeze and the possibility of
stronger aftn/early evening winds for the coastal terms. Winds
all site veer to SW and drop to less than 5 kt by late this
evening and overnight.

Extended Outlook...MVFR/IFR flight restrictions are likely in
association with thunderstorms later Fri thru early Sat. Some
of the storms may be strong to severe. Mainly VFR expected
Sunday thru Monday.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 300 AM Thursday...Winds will remain 10 kts or less
through today as they shift from NE-E around to the SE to S as
high pressure extending across the waters from the north shifts
further off shore. The sea breeze will give a little spike to
the winds this afternoon. Seas will remain fairly benign with
heights less than 3 ft. A small SE swell around 9 seconds will
mix in. Winds will veer slightly more by Fri morning as Bermuda
High begins to dominate.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 400 AM Thursday...Deteriorating wind and sea conditions
expected thru this period. Ahead of the pre-frontal trof, SW
winds will increase to 15 to 20 kt during Friday and maintain
these speeds into Friday night with gusts to 25 kt being added
to the mix. For Sat, the sfc pg will tighten even more as low
pressure deepens over the Delmarva and Mid-atlantic states. The
sfc cold front dropping southeastward, will be on the doorsteps
by Sat morning. Models take the cold front across the local
waters late in the day Sat or Sat evening. Expect active SW to
WSW winds ahead of the cold front that will likely breach SCA
thresholds until the CFP, Sat evening. After FROPA, winds will
veer to the N-NE around 15 kt.

Significant seas will undoubtedly be dominated by wind driven
waves at 5 second periods on Fri, and around 6 second periods
during Sat. Seas will build to 3 to 5 ft during fri and reach 4
to 7 ft by and during Saturday. The 7 footers primarily the
waters from off Cape Fear to Little River Inlet. This a result
of a longer fetch due to the strong WSW-W wind directions during
Sat.

LONG TERM /SATURDAY THROUGH MONDAY/...
As of 300 PM Wednesday...A significant wind-shift will occur
Saturday from WSW to NNE, as a strong cold front for late July
crosses the coast Saturday afternoon or evening. It is possible
a Caution headline or even an Advisory may be needed for gusty
winds ahead of and just behind the front. In addition...TSTMS
and showers will be more numerous Saturday and a few storms may
be strong to severe. NE winds 15 KT Sunday will begin to veer
Monday to E-SE, with seas of 2-4 feet, highest offshore. Sunday
seas a bit messy, as residual SSW waves every 6 seconds mix with
a NE chop and weak SE swell waves. Isolated showers will dot
the waters Sunday and Monday but of light intensity.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.

&&

$$
SYNOPSIS...DCH
NEAR TERM...RGZ
SHORT TERM...DCH
LONG TERM...MJC
AVIATION...DCH