Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 190742
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
342 AM EDT Sat Aug 19 2017

.SYNOPSIS...
High heat and humidity will continue today and Sunday with
temporary relief from scattered afternoon and early evening
showers and thunderstorms due to a slowly approaching cool
front and it`s interaction with an inland progressing sea
breeze. This front will stall in close proximity to the coast
during the weekend before dissipating Monday. High pressure will
build across the area from the western Atlantic Tuesday and
Wednesday, followed by another cool front approaching from the
northwest late Wednesday thru Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 330 AM Saturday...A weak mid level trough, currently
over the Tennessee Valley, will push a cold front near the
coast later today. This will be the focus for showers and
thunderstorms. Both the NAM and GFS have convection firing
around mid to late morning and lingering through the late
afternoon hours. Once again with precipitable water values
near two inches, heavy rainfall will be the biggest threat.
Tonight should be relatively quiet with guidance painting a
mostly convection free scenario. As for temperatures, there
will be a very slight cooling inland with regards to actual
temperatures and dewpoints. The coast however still remains
very humid with dewpoints in the upper 70s and I will
hoist an advisory for these areas.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 330 AM Saturday...The westerlies aloft will pull back
slightly to the north this period. With rising 5H heights, mid-
level ridging from off the Atlantic will extend westward,
across the FA, across the Gulf Coast States, and reaching Texas
and northern Mexico. The upper low or if it opens up, an inverted
upper trof, will make it`s way across the Gulf of Mexico this
period. At the sfc, a stalled frontal boundary will lie NE to SW
along the immediate Carolina Coasts or just offshore on Sun.
This proximity will allow for convection to develop especially
across the coastal counties with low chance category for POPs.
Further inland, drier air aloft and subsidence will keep
convection to isolated at best during Sun. On Mon, as mentioned
earlier, the upper trof aloft will push westward over the Gulf
of Mexico, with it`s upper trof axis extending and pushing
across the FA during Mon. What ever is left of the frontal
boundary will combine with dynamics aloft to producing a low to
modest chance for convection Mon into Mon evening. POPs will be
hiest across the coastal counties and the southern portions of
the ILM SC CWA. This may jeopardize the solar eclipse viewing
across portions of the FA. Stay Tuned. Stayed close to a
consensus amongst the various model mos guidance. The trend will
be for max temps hier Sun, slightly lower for Mon when compared
to Sun. Min temps, widespread mid to upper 70s, with a few low
70s well inland, ie. west of the I-95 Corridor, depending on sky
conditions.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 300 PM Friday...A flat mid-level ridge will extend
from the Atlantic across the Carolinas Tuesday, then get
suppressed south as a trough carves out across the Eastern
seaboard for the latter half of the week. With no real airmass
change evident in guidance until perhaps Thursday, precipitable
water values will hover around 2 inches until then. Scattered
pulse showers and thunderstorms are expected each afternoon and
evening Tuesday through Wednesday, with the highest chances
Wednesday night through Thursday when convection becomes
organized along and ahead of a frontal boundary. As usual in the
extended period, and especially in August, there is a great
deal of uncertainty with timing the front and determining how
far south it will push. Will hang on to higher PoPs across the
southern CWA on Friday to account for that.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
As of 06Z...Expect VFR conditions through the period. A cold
front will move in close proximity to the coast later today
where a good chance of showers and thunderstorms will reside.
There could be some transitory MVFR conditions with the
activity but confidence is not sufficient to include in the
forecast. Some wind in the boundary layer should keep BR in
check this morning but at worst would only expect a fleeting
report or two of MVFR. Once again not sufficient to warrant
mention in TAFs.

Extended Outlook...Scattered TSTMs Sun through
Wed. Flight restrictions will be possible in early morning
stratus/fog Sun-Wed.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 330 AM Saturday...Winds remain fairly brisk this morning
due to enhanced low level jetting. Speeds are currently in a
10-15 knot range down a few knots from earlier reports. Speeds
will decrease another knot or two then settle into this range
through early morning Sunday. Seas are currently just over four
feet and shouldn`t rise much if any more. Overall a range of 2-4
feet will continue through Sunday morning as well.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 330 AM Saturday...A meandering but basically stalled sfc
frontal boundary in proximity of the local waters, may initially
result in changing predominate wind directions. Overall, wind
directions will basically be onshore this period. The sfc pg
will however remain relaxed thru the period, with speeds
basically around 10 kt or less. Significant seas will be
dominated by a lazy 1 to 2 foot ESE-SE ground swell with periods
8 to 9 seconds Sunday and approaching 10 seconds during Monday.
Wavewatch3 does show a slight increase, up to an additional 1
foot, to the ESE-SE ground swell Mon night into Tue. Sun and MON
afternoons/evenings will see some short period wind chop due to
the sea breeze and it`s inland progression. Of the 2 days,
convection will be more active during Mon, especially across the
ILM SC waters.

LONG TERM /TUESDAY THROUGH WEDNESDAY/...
As of 300 PM Friday...A benign pressure field across the waters
will keep winds 10 knots or less Tuesday, as a weak Bermuda
high pressure remains in place off the coast. Winds will begin
to pick up out of the southwest by Tuesday afternoon as a
surface trough takes shape across the Carolina piedmont. Shower
and thunderstorm activity is expected to remain isolated to
widely scattered over the waters in a general southerly flow
through the period.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...Heat Advisory from 11 AM this morning to 6 PM EDT this evening
     for SCZ053>056.
NC...Heat Advisory from 11 AM this morning to 6 PM EDT this evening
     for NCZ099-105>110.
MARINE...None.

&&

$$
SYNOPSIS...DCH
NEAR TERM...SHK
SHORT TERM...DCH
LONG TERM...CRM
AVIATION...SHK



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