Area Forecast Discussion
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FXUS62 KILM 301957
Area Forecast Discussion
National Weather Service Wilmington NC
257 PM EST Wed Nov 30 2016
Mild southerly breezes will continue through tonight as a cold
front approaches the Carolinas from the west. The front will
move offshore early Thursday morning. Canadian high pressure
will bring drier and cooler weather Thursday through Saturday.
Areas of low pressure developing along a front will bring clouds
and increasing rain chances the first half of next week.
.NEAR TERM /THROUGH TONIGHT/...
As of 300 PM Wednesday...Strong southwesterly winds aloft
continue ahead of a large upper level-low that is still centered
over the northern Mississippi River valley of Minnesota and
Wisconsin. Water vapor imagery is showing the strong jet
rotating up the southeast side of the low with speed nearing 110
knots at 500 mb over the lower Mississippi River valley.
Most of the showers that formed on the convergence boundary this
morning have shifted off the coast with a scattered showers
developing back to the west over Columbus and Bladen counties. The
showers are expected to be isolated to scattered through the early
evening. The 17 UTC HRRR shows the convective line that is moving
across Georgia at this time will approach the western counties
around 7 PM, and will weaken as it moves across the county warning
area through the night. Also, the 12 UTC NAM, GFS and ECMWF all
show this strong line weakening as it moves across the region. The
chances for significant precipitation in our area are not looking as
good with this model cycle. The models are indicating the chances
of precipitation will extend to just after 12 UTC for southeast
South Carolina but earlier for the areas to the west.
The lows overnight will drop into the middle 50s west of Interstate
95 and lower 60s at the coast.
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 300 PM Wednesday...This period will see the remainder of any
showers exiting the southeast North Carolina coast with high
pressure building in behind the cold front. This high pressure is
expected to continue through Friday night.
High temperatures are expect to only be in the upper 60s on Thursday
and with cold air advection behind the cold front highs on Friday
will only be around 60. Low temperatures on Thursday night will fall
into the upper 30s well inland to the lower to middle 40s at the
immediate coast line. On Friday night temperatures will drop into
the middle 30s well inland and 40 to 42 at the beaches.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 300 PM Wednesday...A deep cutoff upper low across the
Baja peninsula will eject out into the southern stream flow
early next week, bringing rain chances to the Carolinas. However
the timing of this remains uncertain owing to extremely large
model differences between the slower GFS and faster ECMWF.
Forecasters at WPC have access to a great deal of data we don`t
at the local NWS level, and noted in their extended discussion
that the ECMWF ensembles resemble the GFS operational run and
its ensembles much more than they do the ECMWF operational run.
For this reason, we favor a GFS-centric forecast for the
Surface high pressure and a low-amplitude upper level ridge
should keep Saturday dry. However by Sunday moisture should
begin increasing in advance of the big upper system ejecting out
of Mexico. While even the fast GFS doesn`t bring the trough to
our longitude until Tuesday, increasing flow of Gulf moisture in
the mid-levels should bring clouds and perhaps a little light
rain to the area Sunday afternoon or Sunday night. Rain chances
then develop again on Tuesday when I`ve increased rain chances
to 40-50 percent.
A northern stream trough which is shown in both the GFS and
ECMWF should roll east out of the Rockies during the middle of
next week and could begin to spread another risk of rain into
the area by late Wednesday.
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
As of 18Z...Area will remain in warm and moist air mass ahead of
cold front through this evening. Persistent fog along the coastal
terminals has broken up for the most part leaving IFR ceilings with
low stratus. Expect gusty southerly winds with some drier air mixing
down to produce mainly SCT to BKN lower ceilings through this
evening. A cold front will track across the TAF sites from west to
east overnight. This should produce a line of showers with gusty SW
to W winds. Have not included thunderstorms in TAFs due to timing of
frontal passing, but expect rapidly moving showers with some heavier
rain and stronger winds possible just ahead and along front from 02-
06z inland and 05-10z along the coast. Post fropa expect some brief
MVFR/IFR fog possible then showing trend of clearing with westerly
winds behind front up through end of TAF period.
Extended outlook...Expect VFR. Expect clouds and pcp back in
forecast by end of period with some MVFR/IFR conditions possible by
NEAR TERM /THROUGH TONIGHT/...
As of 300 PM Wednesday...South winds of around 20 knots are
occurring over the waters this afternoon well ahead of cold
front that is located just west of Georgia to southern
Mississippi. As the front moves closer to the coastal waters the
winds will become southwest and increase to 20 to 25 knots with
higher gust. Seas are running between 4 and 6 feet from 20
miles offshore to the coast. Seas are expected to increase to 5
to 7 feet overnight. A small craft advisory will continue for
all the water through the night.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 300 PM Wednesday...At sunrise the cold front will be
approaching the coastal waters and will move across the waters
during the morning. As the winds direction shifts behind the cold
front they will weaken, and the seas will diminish below small craft
conditions south of Little River around 7 AM and 10 AM north of
By Thursday evening, the winds will shift from the west to the
northwest by Thursday evening, and remain north to northwest through
Friday night. Winds will relax to 10 knots by Friday and seas will
settle out around 2 to 3 feet during this time frame.
LONG TERM /SATURDAY THROUGH SUNDAY/...
As of 300 PM Wednesday...Canadian high pressure over the Mid-
Mississippi Valley will build east into the Carolinas early
Sunday, weakening slightly as the centers sits across the
interior of both states Sunday night. Moderate offshore breezes
Saturday should gradually die down Saturday night, but may get
reenergized Sunday night as a wave of low pressure begins to
take shape along the Georgia coast late.
MARINE...Small Craft Advisory until 7 AM EST Thursday for AMZ254-256.
Small Craft Advisory until 10 AM EST Thursday for AMZ250-252.