Area Forecast Discussion
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FXUS62 KILM 270736
Area Forecast Discussion
National Weather Service Wilmington NC
336 AM EDT Tue Sep 27 2016
A weak wave of low pressure moving just offshore will bring
showers today, mainly along the coast. A cold front approaching
from the west will stall through mid-week before moving across the
area on Thursday, maintaining warm and unsettled conditions. Cool
and dry high pressure will build into the area by the weekend.
.NEAR TERM /THROUGH TONIGHT/...
As of 1030 PM Monday...It looks like the the warm front has passed
just to the north of the forecast area. Some light showers are
approaching the coast as a coastal trough forms. This is as
forecast. Previous discussion follows:
The stationary front that was located just to the south of the
forecast area is slowly moving northward as the observations at
Kingstree and Georgetown are now reporting a more northeast and
east flow with increased dewpoint seen at Kingstree.
The water vapor imagery also is indicting the mid and upper moisture
has begun it shift northward. Scattered convection has developed
along a boundary from Longs, SC to Kingstree. So will continue with
a slight chance of POPs from SC this evening.
The models continue to show the development of a coastal trough with
a low pressure area forming and moving up the coast just offshore on
late tonight. So with this low pressure area will increase
precipitation chances to ~30-40% along the coast and a 20% chance
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 3 PM Monday...The short term forecast period will be marked
with a cold front sliding into the forecast area and then
stalling. This front will be a focal point for showers and
isolated thunderstorms each day.
On the synoptic scale a large upper-level low just north of Lake
Superior will shift to Ohio Valley by Wednesday night. This feature
will be bringing a significant air mass change but this does not
begin until after the short term forecast period.
The slow moving cold front will be the focus for the heaviest rain
on Wednesday into Wedensday night with QPF values running between
just over 1". Maximum Temperatures on Tuesday and Wednesday are
expected to rise to the middle 80s with the warmer temperatures west
of Interstate 95. For lower temperatures values will range from the
upper 60s inland to the lower 70s at the coast.
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 300 AM Tuesday...The extended remains a rather lower than
average confidence forecast due to discrepancies in the guidance
handling an anomalous cut-off low across the OH VLY. The ECM
continues to be a slow outlier, but once again the GFS/CMC, which
are in very good agreement today, have slowed from previous
solutions. This continues to lend some support to the ECM, and a
slower progression of the mid-level and surface features is likely,
just not quite to the extent the ECM continues to advertise. While
this upper low spins and ejects only very slowly NE through the
wknd, the surface cold front beneath it will drift east, crossing
the local area late Thursday, before being replaced by Canadian high
pressure. This suggests that cooler and drier conditions will be in
place for the majority of the extended, with temps at or slightly
below seasonable norms, and a nice early fall weekend is possible.
Must continue to note however that if the ECM ends up correct, this
front may not cross until Saturday, leaving much warmer and
unsettled conditions in place through the first half of the wknd.
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
As of 06Z...Slow moving cold front well NW of the terminals, and a
developing weak low pressure along the coast, will maintain ample
cloudiness and possible showers through the valid period. A few
showers have developed along the coast so far this morning, and this
is likely to continue through daybreak. Do not expect coverage to be
widespread enough for a VCSH mention, so have added a TEMPO group at
ILM/CRE/MYR for periodic and brief MVFR. The inland terminals will
likely remain dry as the showers along the cold front to the NW are
forecast to dissipate as they drop SE. While cloud cover will be
significant, much of it will remain the mid-levels, so light fog is
possible overnight at LBT/FLO, with winds just above the surface
likely too strong for any IFR vsby restrictions.
Scattered showers will again be possible during Tuesday aftn/eve,
but coverage is expected to be light enough that no mention of any
restrictions has been added attm. Best chance for showers during the
day will be along the coast, but will handle this potential with
later updates. Winds will be generally from the east and less than
10 kts beneath VFR cigs. More stratus will again be possible Tuesday
night, especially along the coast.
EXTENDED OUTLOOK...Scattered SHRA/TSRA Tuesday through Thursday.
Cold frontal passage Thursday. VFR expected fRI/SAT.
NEAR TERM /THROUGH TONIGHT/...
As of 1030PM Monday...Latest obs continue to show easterly winds
of 10 to 15 kts with seas of right around 3 ft. This fits in well
with the going forecast. No changes made with latest update.
Previous discussion follows:
A stationary front is located near the Georgetown coastal waters
and is expected to shift northward overnight. To the south a
coastal trough will develop with a low pressure area moving to the
southern coastal waters by daybreak.
Winds will mainly be from the east overnight at 10 to 15 knots with
seas ranging between 2 to 4 feet. A 1 to 2 foot easterly swell is
also expected to continue through the period.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 3 PM Monday...As a coastal low shifts northward along the
coast, a slow moving cold front will stall before shifting off the
coast late wednesday night. winds are expected to shift to the
southwest tuesday night but winds speeds are expected to be 10-15
knots. seas will continue to run between 2 and 4 feet. Showers and
thunderstorms are possible throughout most of this period.
LONG TERM/FRIDAY THROUGH SATURDAY/...
As of 300 AM Tuesday...A cold front will slowly move across the
waters on Friday, causing winds to shift from SW at 5-10 kts early,
to NW at 5-10 kts late. As high pressure builds down into the area
behind this front on Saturday, winds will shift further to the NE,
but remain at relatively weak speeds due to the weak pressure
gradient. Seas will be 2-3 ft Friday with a southerly 5-6 sec wave
being the predominant wave group. By Saturday, wave heights will
fall to around 2 ft, possibly building again late in the period as
some forerunner swell from a developing tropical system well out in
the Atlantic enters the waters.