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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 221651
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
1251 PM EDT Wed May 22 2019

.SYNOPSIS...
Just slightly warmer than normal afternoon today will give way
to an extended heat wave with well above normal temperatures.
There are no appreciable rain chances over the course of the
next seven days as high pressure dominates the weather.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 1000 AM Wednesday...Fairly decent cloud layer over area,
but overall thinning and still expect this trend to continue to
lead to partly to mostly sunny skies this afternoon. Forecast
on track for a relatively cooler day with NE to E on shore flow
and temps closer to 80 near the coast and mid to upper 80s
inland.

Previous discussion: A surge of easterly winds early this
morning is moving across the area, spreading low clouds inland
from the coast. Models have a surprisingly good handle on this
almost mesoscale event and show clouds thinning from east to
west later this morning. It may take until afternoon to get
cloud ceilings to break across the interior Pee Dee region where
cloud depth near 2000 feet will resist the strong May sun for a
few additional hours.

In the mid and upper levels strong high pressure is building across
Georgia and South Carolina. Forecast 500 mb heights exceeding 591
dam this afternoon and 593 dam Thursday should be at least 100
meters above average and among the highest values observed in May
according to the SPC sounding climatology website using CHS data.

The maritime boundary layer moving onshore is relatively cool and
should keep high temps in the upper 70s and lower 80s near the coast
today. Inland temps should still reach the mid to upper 80s.
Slightly drier air should make significant inroads across North
Carolina where dewpoints will probably dip into the 50s this
morning. If we get popup showers this afternoon the best potential
should be across Darlington and westward into central South Carolina
where higher dewpoints will exist along with modest surface-based
instability. Forecast PoPs near Darlington are only 20 percent.

High pressure across the Mid-Atlantic states will move offshore
Thursday. This should veer our surface winds from east to south.
Despite an increase in temperatures and dewpoints, a stronger
subsidence inversion aloft will probably cap off any potential for
showers.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 300 AM Wednesday...Thursday night ends the slightly
cooler conditions as the near term front lifts back to the north
and West Atlantic high pressure/return flow resume. Only low
level flow will turn to the south however so the moisture will
not grow very deep. Dewpoints will be creeping up but will not
quite reach the muggy levels seen earlier in the week. So even
as Friday highs soar into the low 90s the apparent temperatures
will only run a few degrees higher and stay well short of any
Heat Advisory. A backdoor cold front drops into the area on
Friday night bringing little more than a windshift over northern
zones.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 300 AM Wednesday...At the surface, backdoor front washes
out over the area on Saturday. Mid level ridge over the Gulf
States on Saturday to bring very unseasonably warm conditions
locally. Sunday and Monday then grow even hotter, less due to
thermal advection and more due to warmer starts and building low
level warmth (GFS forecast soundings show a 7kft boundary layer
by Monday afternoon). Record highs appear to be in jeopardy,
some dating back to the 1950s. The low level ridge above the BL
never makes it offshore, still precluding moisture deep enough
for surface dewpoints that will push the area into Heat Advisory
realm. Some guidance has been suggesting that the ridging aloft
should start to weaken early next week leading to a very
gradual abating trend in the heat. Given the common model bias
of breaking down such hot ridges too quickly have opted to keep
the forecast rain-free at this time and will show a continuation
of the heat wave.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
As of 18Z...Predominately VFR throughout the period. A cold
front has pushed south of the area and stalled. Behind the
front, morning stratus is continuing to erode with dry air
advection from the east. Expect VFR conditions to return to all
terminals over the next few hours. Winds will continue to be
from the east at 10-15 knots today until this evening when the
front weakens along with the associated pressure gradient. A few
areas of stratus are possible after 03Z tonight, but will keep
VFR for now.

Extended Outlook...Continued VFR through the weekend as high
pressure dominates. Hot. Slight chance of brief MVFR conditions each
morning from low stratus and/or fog and afternoon TS.

&&

.MARINE...
As of 1000 AM Wednesday...1026 mb high pressure centered across
the Mid-Atlantic states has pushed a reinforcing surge of east-
northeast winds across the area. Sustained wind speeds have
increased to 15-20 kt north of Cape Fear, and should increase to
around 15 kt south of Cape Fear. These winds should continue
through most of the day, gradually diminishing and veering
southeasterly tonight, then becoming southerly on Thursday
afternoon as the high moves off the Mid-Atlantic coastline. All
models are in agreement with this scenario and this is a high-
confidence forecast.

Seas should build to 3-4 feet this morning (highest near and north
of Cape Fear) in a 4-second wind chop. Beneath this, a smaller 9-
second southeast swell will continue. As winds diminish overnight
into Thursday seas should fall to around 2 feet.

Thursday night through Friday night: Southerly flow generally
expected through the period. A backdoor cold front will sink into
the area Friday night possibly turning flow very briefly E or even
NE, mainly over northern waters. Seas generally 2-3 ft. Backswell
from a system off New England coast largely gets wave shadowed by
OBX and largely stays east of the forecast zones.

Saturday through Sunday: Boundary both lifts out to the north and
falls apart over the weekend. This leaves Atlantic high pressure to
reassert itself albeit weakly. Light southerly winds and 2 to
possibly 3 ft seas to continue.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.

&&

$$

NEAR TERM...TRA/RGZ
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...21