Area Forecast Discussion
Issued by NWS Wilmington, NC-- Remove Highlighting --
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FXUS62 KILM 180748
Area Forecast Discussion
National Weather Service Wilmington NC
248 AM EST Wed Jan 18 2017
A cold front will drop south through the region today. Weak
high pressure will follow on Thursday. Low pressure will move up
from the Gulf Coast and drag a cold front across the area on
Friday. High pressure will build in on Saturday before another
system brings unsettled weather for late Sunday into Monday.
.NEAR TERM /THROUGH TONIGHT/...
As of 245 AM Wednesday...The bulk of the mid-level shortwave energy
will swing across the central Appalachians and VA today, before
heading out to sea. The southern most spoke of this energy will
skirt the northern reaches of the forecast area. 07z Radar shows
some light returns showing up along the NC and TN line and then
stretching across the VA/NC border. The high resolution model, HRRR,
shows some light showers skirting areas along and N of a BBP to ILM
line after 15z. These showers will be occurring just ahead of a cold
front which should slip S of the area this afternoon, shifting
westerly winds to the N. The risk of showers will come to an end
prior to dusk. In fact, mostly cloudy skies will begin to clear
almost immediately behind the front this afternoon.
Given the magnitude of mid-level dry air and with a deep westerly
flow in place, it seems reasonable to keep the risk of measurable
rainfall low and confined to the northern third or so of the CWA.
Where rain does measure, it will be on the order of just a few
What most people will notice about today is that when they head out
early this morning, it is just too warm for this time of year. We
are above the normal high by several degrees already this morning.
Consequently, today`s highs will be well above normal, lower to mid
70s. You will also likely notice the gusty winds as 35-45 kt of
wind, riding 2-3 kft above the surface, partially mix down.
Tonight, skies will clear and high pressure will build toward the
area from the W. Winds will gradually become very light which will
increase the effects of radiational cooling. Lows will be in the
lower to mid 40s with some upper 40s to near 50 along portions of
the immediate coast and South Santee River area.
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 245 AM Wednesday...High pressure will be in place Thu, moving
offshore Thu night. Clouds will begin to increase during Thu
afternoon, but it will remain dry with above normal temps, lower to
mid 60s. A storm system will be moving across the Midwest with its
complex frontal system trailing south across the Tennessee Valley
and south to the eastern Gulf Coast Friday morning. Moisture
advection into the Carolinas will peak overnight Thu into the first
portion of Friday and this is when we will advertise generally
likely pops. The mositure return looks a little weaker and briefer
as compared to 24 hours ago and this is partially due to weaker
jetting. At this time, rainfall amounts should fall between one
tenth and one quarter of an inch. Shortwave energy pivoting across
the FA may spawn an area of weak low pressure along the North
Carolina coast Fri night as the front stalls in close proximity
offshore. Will contine to show POPs trending down Fri afternoon and
will keep any showers offshore Fri night.
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 245 AM Wednesday...An unsettled weekend ahead with the
possibility of severe weather highlights the extended forecast.
Saturday starts off with a broad southwest flow aloft with weak high
pressure at the surface. Weak shortwaves in this flow along with
some isentropic lift keep pops in the forecast through the day
Sunday when a more organized system approaches from the southwest.
Guidance shows a deep vertically stacked cyclone developing in the
Mississippi Valley moving east throuigh the Carolinas through the
day Monday. A deep subtropical plume of moisture accompanies the
cold front late Sunday into Monday morning with accompanying high
shear and low cape values. Low level wind speeds reach close to 60
knots at 850mb so any convective cells could translate strong winds
to the surface. As is usually the cast this time of year low level
instability will be the issue.
The mid level low slowly moves across the area Monday into early
Tuesday and depending on timing and any heating available some
instability showers could develop. Mid levels will be drying out
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
As of 06Z...Satellite imagery shows partial clearing continuing
across the region as warm front has lifted well north of the
region. Cold front across eastern TN will move into extreme
western NC this morning and continue to move eastward throughout
the day. Main issue continues to be the increased low level jet
at H8 ahead of this frontal boundary and the threat for low
level wind shear of 25-35 knots at about 1500 feet AGL through
this morning. Have kept low level wind shear in the forecast
for Florence, Wilmington, and Lumberton. Another concern is sea
fog developing off the coast, but as of now, it is expected to
remain just offshore of the two Myrtle Beach airports. However,
a slight shift in the wind direction could bring this fog
onshore. It is hard to discern on satellite so will have to wait
on surface reports for verification.
Not much change from previous discussion regarding stronger
westerly winds in advance of a cold front mixing down to the
surface during the morning with wind gusts in the 18-25 knot
range possible. Again cannot rule our some light showers from a
mid-cloud deck near the front as it passes with best chance in
the Wilmington area. Still will keep prob in the tafs for the
other terminals with a tempo for KILM along with MVFR conditions
in ceilings, VFR throughout across all other terminals.
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 245 AM Wednesday...We will initialize with a Small Craft
Should Exercise Caution headline for the northern waters and keep
the headline through the day. The wind direction ahead of a cold
front will be SW. The wind will shift to the N with passage of the
front this afternoon and lastly across the far southern waters early
this eve. Wind speeds today will be up to 20 kt N and 15 to 20 kt S.
Seas will be up to 4 to 5 ft, otherwise 3 to 4 ft today. High
pressure will build in from the W and NW tonight. The wind direction
will veer slightly, from N to NNE/NE overnight. Wind speeds tonight
will generally be 15 to 20 kt, but will show a downward trend toward
morning. Seas will be up to 3 to 4 ft in the eve with some 5 ft seas
across the outer northern waters. Seas will subside to 2 to 3 ft
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 245 AM Wednesday...High pressure Thu will move offshore Thu
night. An area of low pressure and its associated frontal system
will move across the area Fri. Weak low pressure may develop Fri
night as mid-level shortwave energy pivots across a frontal
boundary, in close proximity offshore. NE winds Thu will become E
and then SE Thu night. The wind direction will further veer to SW
during Fri and then W and NW overnight Fri. Wind speeds of 10 to 15
kt will be common through the period. Seas should not exceed 2 to 3
ft during the forecast period.
LONG TERM /SATURDAY THROUGH SUNDAY/...
As of 245 AM Wednesday...Weak high pressure will lead to benign
conditions for Saturday and most of Sunday for that matter. Wind
speeds will be mostly ten knots or less and the synoptic direction
from the east/northeast. Speeds do pick up a little later Sunday via
an approaching front and the direction veers to the southeast.
Significant seas will be 2-3 feet.