Area Forecast Discussion
Issued by NWS Wilmington, NC-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS62 KILM 171724
Area Forecast Discussion
National Weather Service Wilmington NC
1224 PM EST Tue Jan 17 2017
A warming trend will occur today into Wednesday ahead of a cold
front which will drop south through the Carolinas late Wednesday.
Cooler and drier high pressure will follow on Thursday. Low
pressure moving up from the Gulf Coast will drag a warm front
through the area on Friday. High pressure will build in on
Saturday before another system brings unsettled weather for
Sunday into Monday.
.NEAR TERM /THROUGH TONIGHT/...
As of 945 AM Tuesday...Dense fog advisory continues and was expanded
into inland NC counties through 15Z. RAP initialization appeared best
and served as the main guidance used for the update. The soupy
airmass has prevented surface insolation and the diurnal curve had
to be slowed. Early vis pics show some breaks forming over Grand
Strand. This should allow for a feedback as the insolation leads to
warming, further breaking up the low cloud deck. The surface warm
and humid air just off the coast (temp 71, dewpoint 63 at 41013) to
flow readily ashore, aided by a seabreeze. sticking point in the
forecast is that SREF and RUC are really liking the development of
sea fog as this occurs. This will mostly be a marine issue and the
CWF and marine grids have been updated, but parts of coastal
Brunswick may have difficulty shaking the fog and stratus today.
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 300 AM Tuesday...The flow remains largely westerly and
marginal moistening of the column is brief with dry air in the mid
levels formidable Wed. The cold front is expected to become oriented
E-W and should move to our S during the afternoon and early eve
hours of Wed. Isolated to scattered showers should not produce more
than a few hundreths of qpf where measurable rainfall does occur. We
are still expecting the warmest day of the week Wed, lower to mid
70s. The Brunswick County coast and southern New Hanover County will
be short changed due to the prevailing flow being onshore, thus
mainly shy of 70 here.
A brief surge of colder and drier air Wed night with skies clearing
as high pressure builds into the area. Low temps will drop into the
mid and upper 40s with some lower 50s along portions of the
immediate coast and the South Santee River area.
This high will quickly move overhead Thu and then offshore Thu
night. Clouds will begin to increase during Thu afternoon, but it
will remain dry with above normal temps. Eyes will then turn to a
storm system, which by this time, will be moving across the Ohio
Valley with its complex frontal system trailing south across the
Tennessee Valley and south to the eastern Gulf Coast. Moisture
advection into the Carolinas will be in full swing toward the tail
end of the period as Conveyor belt of deep moisture transports Gulf
of Mexico moisture north as 50 kt low level jet begins to impinge on
the area. Will show pops ramping up overnight Thu.
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 300 AM Tuesday...Continues to look unsettled through much
of the long term period as first system brings some pcp to the
area on Fri in a warmer and moister southerly flow. Once this
system lifts out of the area, should see a break Fri night into
Sat with some drier air and sunshine on Saturday before next
system spreads clouds and pcp our way once again Sat night into
Sunday. This system may keep clouds and chc of pcp over the
Carolinas through Monday. Clouds and pcp will keep less of a
diurnal swing with highs reaching into the 60s most days.
.AVIATION /18Z TUESDAY THROUGH SATURDAY/...
As of 18Z...The last of this morning`s widespread dense fog and
low stratus event should wrap up between 1800Z-1930Z in the
Florence SC to Lumberton NC corridor. Satellite imagery shows
clearing proceeding from both the southwest and southeast. A
warm front at the surface defines the southeastern edge of the
low clouds, and this feature should sweep across the area in the
next couple of hours, allowing warmer and more humid
southwesterly winds to mix down to the surface.
A southwesterly low level jet should increase to 25-35 knots at
1200 feet AGL this evening, and low level wind shear has been
added to the forecasts for Florence, Wilmington, and Lumberton.
Sea fog potentially developing off the coast is expected to
remain just offshore of the two Myrtle Beach airports, however a
10-20 degree error in wind direction could bring this fog
Wednesday morning stronger westerly winds in advance of a cold
front should mix down to the surface with wind gusts in the
18-25 knot range possible. Some light showers from a mid-cloud
deck could also sweep across the area near the front, best
potential in the Wilmington area.
Extended Outlook...IFR ceilings are possible in low stratus
Friday and Friday night as the next warm front and rainfall
event develops. IFR ceilings could continue into Saturday
morning as models indicate a cool air wedge possible.
NEAR TERM /THROUGH TONIGHT/...
As of 945 AM Tuesday...With the warm front dissipating warm and
humid air will flow into the coastal zones. Models are in
fairly good agreement that as this airmass flows over the cooler
water it becomes cooled to its wetbulb and some marine fog
develops. The forecast has been updated to reflect as such. Will
continue to monitor new guidance and satellite imagery to
assess the need for a fog advisory.
As of 630 AM Tuesday...A warm front will move across the waters
today. Light NE or ENE winds will become SW today and then increase
to 15 to 20 kt tonight ahead of a cold front. Seas will respond to
the increasing wind energy, building from 2 ft or less to 3 to 4 ft
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 300 AM Tuesday...A cold front to the NW will become oriented E-
W as it moves across the waters during the afternoon and should be
south of all the waters by/during the early eve hours of Wed. SW to
W winds Wed will shift to N in the wake of the front. Wind speeds up
to 15 to 20 kt are expected prior to the front and then for several
hours after the passage of the front. Seas will be mainly 3 to 4 ft
Wed and Wed night, although some 5 ft seas across the outermost
northern waters will be possible. NE winds near 10 kt Thu will veer
as high pressure moves overhead and offshore. Toward the tail end of
the period, expect SE and S winds to be on the increase ahead of the
next storm system. Seas for Thu and Thu night will be 2 ft or
LONG TERM /FRIDAY THROUGH SATURDAY/...
As of 300 AM Tuesday...Light and variable winds early Friday
will become on shore and eventually southerly as low pressure
lifting up through the Mississippi Valley pulls a warm front
through the Carolinas. This southerly push will bring seas up to
3 to 4 ft most waters late Friday into early Saturday. A weak
northerly flow will develop Sat allowing seas to subside down to
3 ft or less through early Sunday.