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274
FXUS62 KILM 171028
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
630 AM EDT Tue Sep 17 2019

.SYNOPSIS...
Hurricane Humberto will move farther out to sea in the days
ahead, but will send increasing swell waves toward our beaches,
producing strong rip currents. A cold front will cross the
coast later today, bringing cooler and drier air mid through
late week.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
An upper level ridge extending from the Mississippi Valley across
the Great Lakes will break eastward toward New England tonight and
Wednesday as a strong shortwave dives south well off the East Coast.
Convergence aloft and subsequent downward motion downstream of the
ridge will cause surface high pressure to expand across the
northeastern United States, pushing a cold front southward into the
Carolinas this evening. Since northeasterly low-level winds are
already in place, look for an increase in mid-level cloudiness and a
drop in dewpoints to signal the front has pushed through.

850 mb temps in the +16C to +18C range should support inland highs
in the lower 90s today, with mid-upper 80s near the coast. We`re
probably getting close to the last few 90 degree readings of the
year as October (with its rapidly shortening days and lowering sun
angles) is only two weeks away. There appears to be too much dry air
aloft within the subsidence inversion to allow for a significant
chance of showers this afternoon or this evening. Dewpoints plunging
into the 50s on Wednesday will similarly keep rain chances low.
Highs on Wednesday should only reach 80-82 across the area as cooler
Canadian air spreads in from the northeast.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
Essentially an amplified blocking pattern in place at the mid
levels as Humberto starts an extratropical transition in the
Atlantic and troughing across the Western U.S. In between a
massive ridge will keep high pressure in place nosing down into
the Carolinas. Long story short, very nice conditions for this
period with cool temperatures, lots of sunshine and a bit of a
breeze from the northeast. Still expecting good coverage of 50s
for lows both Thursday and Friday mornings with highs probably
not eclipsing 80 in most areas Thursday.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
The mid level blocking period breaks down into the
weekend as a zonal flow develops. The forecast remains dry
throughout the period and in fact the summer time pattern of a
Piedmont Trough shows up late but with limited moisture.
Temperatures will show a gradual increase from below normal early to
somewhat above early next week.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Satellite shows some stratus in Pender county trying to sing south.
Think the sun will mix the stratus out before it gets to ILM. Look
for VFR conditions and a moderate northeast wind. Looks like a
southeast sea breeze in North Carolina by 18Z.


Extended Outlook...VFR.

&&

.MARINE...
Hurricane Humberto moved to within about 300 miles of Cape Fear
overnight but is continuing to move east and away from the Southeast
coast. Breezy northeast winds are due to the pressure gradient
between Humberto and a large area of high pressure across
southeastern Canada. These winds will actually increase tonight to
20 kt or stronger as a cold front passes through from the north
during the evening hours. Shower chances appear too low for mention
in the forecast, but breezy northeast winds will continue through
Wednesday.

Large 10-second southeasterly swells coming at us from Hurricane
Humberto are adding several feet to shorter period waves produced by
the northeast wind. Combined seas currently 4-7 ft are expected to
build by another foot tonight. The Small Craft Advisory will
continue.

Little in the way of forecast changes for the marine
community as the big features and details are certainly intact.
Wedging high pressure from the northeast, courtesy of a massive
blocking ridge across the Mississippi Valley. Northeast winds of 20
knots or so will continue as will the seas of 4-7 feet. Once again
extended the small craft advisory forward for all waters into Friday
morning. Conditions will be relaxing shortly after this with a
slowly evolving return flow for the weekend and certainly lower
seas.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...Beach Hazards Statement from 8 AM EDT this morning through
     this evening for SCZ054-056.
     High Rip Current Risk from 8 AM EDT this morning through this
     evening for SCZ054-056.
NC...Beach Hazards Statement from 8 AM EDT this morning through
     this evening for NCZ106-108-110.
     High Rip Current Risk from 8 AM EDT this morning through this
     evening for NCZ106-108-110.
MARINE...Small Craft Advisory until 8 AM EDT Friday for AMZ250-252-254-
     256.

&&

$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43
MARINE...TRA/SHK