National Weather Service United States Department of Commerce

 


000
FXUS62 KILM 262349
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
749 PM EDT THU MAY 26 2016

.SYNOPSIS...
High pressure will continue to bring sunshine and warmth through
Friday. Clouds and rain chances will increase over the weekend as
low pressure develops in the Bahamas and very slowly approaches.
This system may take until Tuesday to clear out of the Carolinas
brining a prolonged period of unsettled weather.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 645 PM Thursday...Other than a couple light short lived
showers along the sea breeze as it pushed across Horry and Bladen
counties early this evening, the FA will remain POP-less tonight.
Diurnal Cu fields across the FA, will dissipate altogether by or
just after sunset. Debris clouds in the mid and upper levels from
convection well upstream, will further decay as they push toward
and across the FA overnight. An active sea breeze, having
progressed well inland, will take up to several hours after
sunset before finally dissipating. Low temps continue in the ball
park with no tweaking applied.

Previous......................................................
AS OF 330 PM Thursday...An extensive cu field has developed this
afternoon with thickest coverage along and near the sea breeze
front over the coastal counties. Convective development beyond
this point is being hampered by very dry air aloft. Still
expecting a dry and warm afternoon with highs in the mid to upper
80s.

A broad area of high pressure over the western Atlantic and eastern
Carolinas will slowly retreat to the east and north as a developing
tropical or sub-tropical low over the Bahamas drifts slowly to the
NW with little change in intensity. Model guidance and ensembles are
in good accord with this scenario. This will keep up a mild
southerly flow into the nighttime hours with winds becoming light
and variable after midnight. A consensus of guidance has
temperatures bottoming out in the lower to mid-60s. Skies will
become mainly clear overnight as diurnal cu fades with the sunset.
Light winds, clearing skies and elevated dewpoints will allow for
fog development of patchy to areal extent in coverage. Expect
greatest fog development over our coastal counties.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 330 PM Thursday...The western limb of a broad high pressure
system over the western Atlantic will extend over the eastern
Carolinas at the beginning of the period but will slowly retreat to
the north and east as a developing tropical or sub-tropical low over
the Bahamas drifts slowly to the NW with little change in intensity.
As mentioned in the Near Term discussion above, model guidance and
ensembles are in good accord with this scenario. Model soundings do
not move deep layer moisture in until around daybreak on Saturday
morning, so until then we can expect fair skies, dry weather and
warm temperatures. Although there is significant forecast
uncertainty regarding development of this system, it looks likely
that deep layer moisture will advect in beginning on Saturday.
This will bring increasing chances for showers or thunderstorms,
especially along the coast, beginning on Saturday morning, with
chances increasing through the remainder of the period. It is
unlikely that winds associated with this system will be a concern
through the short term as guidance continues to show that this
feature will be weakly organized and slow to develop.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 3 PM Thursday... Well, there are some facets of the extended
that are becoming a bit clearer and other things not so much. The
development and track of the Bahamas system is becoming better
agreed upon between various models. Most seem to take it into the
South Carolina coast some time (late, probably) Sunday. The GFS and
EC also agree that from there the system will grind to nearly a halt
with just a slow NE drift up the coast on a slow inland track. Only
the Canadian has a quicker movement. The slower solution preferred
following coordination call with NHC/WPC. So while this will no
doubt be refined in the future (especially if flights into the
system begin tomorrow) the more uncertain points remain the strength
of the system and the envelope of moisture. Should a long duration
of effects from this system pan out they will likely be Sunday
through Tuesday. Potential heavy rain probably the greatest threat
at this point but even that may not be overly high. Secondary
effects likely beach related in the form of rip currents. And then
whenever the center of the storm moves by a tornado threat certainly
seems likely to develop. With the current forecast the rain and
tornado threat appear slated for Monday. With the slow exit of the
system improvement will be gradual Tuesday into Wednesday as we
transition to a sunnier and warmer pattern with little appreciable
rain chances.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
As of 00Z...Potential for marginal MVFR due to patchy fog early
Friday morning. Otherwise expect VFR through the valid TAF period.

VFR prevails across the area this evening with southerly
winds around 10 kts or less. Expect winds to become light and
variable late overnight into early Friday morning, with the
potential for patchy light fog towards morning. Would not
entirely rule out brief MVFR due to fog early, but confidence is
low. On Friday, expect VFR to prevail with increasing southeast
winds around 10 kts.

Extended Outlook...MVFR possible in scattered to numerous showers,
isolated TSTMS this weekend. Otherwise expect VFR.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 645 pm Thursday...Tranquil boating conditions to continue
overnight into Friday. For tonight into Friday, the sfc ridge
axis from the high`s center offshore from the Carolinas, will
extend back to the sw and onshore in the vicinity of the Savannah
River. Look for winds to switch back to the e or se. The sfc pg
will remain relaxed with wind speeds 10 kt or less. Significant
seas will hover around 2 feet. Expect little input from wind
driven waves. This leaves a 1 to 2 foot ese ground swell
at 8 second periods dominating the significant seas.

Previous......................................................
AS OF 330 PM Thursday...A broad area of high pressure over the
western Atlantic will slowly retreat to the east and north as a
developing tropical or sub-tropical low over the Bahamas drifts
slowly to the NW with little change in intensity. This will keep
up a southerly flow of 10 to 15 kts through the nighttime hours.
Seas will remain right around 2 ft through the period.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 330 PM
Thursday...The western limb of a broad high pressure system over the
western Atlantic will extend over the waters at the beginning of the
period but will slowly retreat to the north and east as a developing
tropical or sub-tropical low over the Bahamas drifts slowly to the
NW with little change in intensity. This will bring increasing
chances for showers or thunderstorms, along with gradually
increasing winds and seas, beginning early on Saturday after a day
of mild wind and sea conditions on Friday. At this point it is
unlikely that winds associated with this system will be strong
enough to warrant any advisories or warnings for the short term as
guidance still shows a weakly organized and slowly developing system
at that time. For now expecting maximum winds of 15 to 20 kts on
Saturday night, with seas building to 3 to 5 ft.

LONG TERM /SUNDAY THROUGH TUESDAY/...

As of 3 PM Thursday... Onshore flow through the entire long term
period now appearing likely as the low slated to develop over the
Bahamas enters the area and just about stalls. Swells could push
waves to near SCEC thresholds but as the system is progged to remain
quite weak that`s likely about it. This also means that wind remains
quite light through the period though the track of the system is
uncertain and this translates to uncertainty with regards to
direction.

&&

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

&&

$$

SYNOPSIS...MBB
NEAR TERM...DCH/REK
SHORT TERM...REK
LONG TERM...MBB
AVIATION...SGL