FXUS62 KILM 231912

Area Forecast Discussion
National Weather Service Wilmington NC
312 PM EDT Wed Aug 23 2017

An approaching cold front will bring thunderstorms through
Thursday, some of which may be strong. Canadian high pressure
will bring an early fall feel Friday and through the weekend.
We will be watching the tropics for any development of low
pressure off the Southeast coast early next week.


As of 300 PM Wednesday...Mid level troughing moving across the Ohio
Valley will push a cold front to the coast through the period.
A clean passage is eventually expected however it will take some
time. For the afternoon and overnight hours convection will
slowly develop inland with the front and according to most high
resolution guidance form somewhat of a line later this evening.
This line should push south and east through most of the area
through about 7-8Z. There remains a severe threat primarily in
the form of strong winds with the stronger convection. The storm
prediction center continues to advertise a marginal risk over
much of the area. The front will become active again Thursday
afternoon. Overnight lows will remain elevated tonight with
residual heat, clouds and rainfall. Thursday will be a much
different story with regards to temperatures with readings some
five to seven degrees cooler.


As of 300 PM Wednesday...Some cooler and drier air will be filtering
in Thursday night from the northwest behind slow moving cold frontal
boundary. A little rain may linger along the coast due to the later
arrival of the drying. By Friday the front will stall just far
enough south for a rain-free day as a sprawling, cool season-like
1025mb high is centered over the Great Lakes. This high will
show little to no movement Friday night. The movement of the
front, if any will thus be determined by any potential low
pressure development off of JAX. This could also lead to a
coastal increase in moisture.


As of 300 PM Wednesday...A stationary front will be located
well offshore and S of the area Sat with an area of low pressure
positioned on the front, but well offshore. High pressure will
be ridging across the Carolinas from New England. The pressure
gradient between these two features will keep a fairly brisk NE
wind in place across the Forecast Area through the weekend.
This will ensure the cool air is continually reinforced and
highs during the weekend should only be in the lower to mid 80s
and this will be coupled with comfortable humidity levels. Model
profiles continue to be quite dry with precipitable water
values below climatological normals and thus will not include
any mention of a shower or thunderstorm during the weekend. This
pattern looks to hold through Sun. The flow becomes more
onshore and the column begins to moisten Mon and Tue. There may
also be some mid- level shortwave energy impinging on the area
from the SW. Will paint more in the way of cloudiness as a wedge
likely sets up and introduce the potential for some showers and
perhaps a thunderstorm. The probabilities for precipitation
will be highest at the coast.

The heat is not to be found, even early to the middle of next
week with highs only in the lower to mid 80s. Lows will be in
the mid 60s to near 70 through the period.

As a caveat, we will be watching the tropics early next week to
see if a weak disturbance is able to develop somewhere off the
SE coast. Confidence in any development is very low as is its
eventual track.


As of 18Z...VFR conditions will prevail through most of the
afternoon hours. Some scattered convection may affect sites
short term but a more organized line of showers and
thunderstorms should move northwest to southeast across the area
later this evening. The next issuance of the TAFs will
certainly have a better grip on the timing and strength. There
could be some MVFR and even brief IFR with the activity.
Subsequent shifts may want to visit the possibility of fog
across the inland sites early Thursday as well.

Extended Outlook...Showers and t-storms Thursday associated
with a cold front could produce localized IFR conditions.
Most showers and storms will push offshore Thursday night
into Friday. MVFR ceilings could linger, especially near
the coast Friday.


As of 300 PM Wednesday...A cold front will move steadily across the area
tonight with a northerly or at least westerly component to the winds
across most waters by early Thursday morning. The push will be short
lived however with the front wavering back onshore later Thursday
via the sea breeze. A stronger and more pronounced push offshore
will come just beyond this period of the forecast. Back to this
evening and tonight, southwest winds of 10-15 knots will increase to
the lower end of a 15-20 knot range and persist for about twelve
hours or so. Seas will increase to 3-5 feet for a few hours as well.
Lighter winds Thursday should lead to seas more in a range of 2-4

As of 300 PM Wednesday...Cold front comes through early Thursday
night turning winds to the NE by midnight. The NE to E winds will
last for the remainder of the period as a large area of high
pressure sits centered over the Great Lakes and the front remains
stalled to our south. Low pressure developing on the boundary off NE
FL coast gradually should pinch the gradient and allow for a slow
building of wind and seas.

As of 300 PM Wednesday...Persistent and brisk NE winds will
likely require a Small Craft Advisory for much of the period.
The tightening pressure gradient will be the result of high
pressure ridging down into the Carolinas from the N and an
offshore front and area of low pressure. NE winds will be
around 25 kt for much of the period. Seas will be 5 to 7 ft and
perhaps up to 8 ft by Mon.





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