Area NWS Forecast Discussion
FXUS62 KILM 221122

Area Forecast Discussion
National Weather Service Wilmington NC
722 AM EDT Fri Jun 22 2018

Hot and humid conditions with scattered thunderstorms
will continue today through the weekend. A cold front
accompanied with thunderstorms will move across the area
Monday night. In it`s wake, high pressure will ridge down
from the north and supply a drier air air mass with
temperatures dropping back to near normal Tuesday thru
Thursday of next week.


As of 615 AM Friday...Update to POPs. Weak forcing from aloft
and a weak sfc trof oriented from WNW to ESE across the ILM NC
CWA will both combine to produce widely scattered showers early
this morning thru mid daytime morning. Whether that transitions
to thunderstorm activity at this point looks minimal based on
the previous fcst.

As of 330 AM Friday...The mid level ridge that has been in
place to our west for so long bringing the heat has finally
been quashed by a trough dropping into the MS/OH valley region.
The center of this trough stays far enough to our west to
preclude any height falls and thus deep layer lift. Despite the
slight mid level veer from west to southwest there is not any
substantial moistening of forecast soundings. In fact, quite the
contrary PW values drop from 2.3" to 1.9". Factoring in a
little persistence (no measurable rainfall yesterday) will
minimize POPS today. Will carry isolated coverage area wide as
seabreeze and piedmont trough will both try to make
contributions. Friday night a few disturbances will streak by to
our west in the southwesterly flow. Most of the area will be
too stable for this to matter, but a few showers or shallow
thunderstorms could develop over the marine environment.


As of 330 AM Friday...The upper closed low over the Southern
Great Lakes will be in the process of opening up into a s/w trof
as it gets absorbed in the westerlies aloft. The mid-level trof
axis extending from the transitioning upper low will push from
west to east across the FA during Sat. This forcing will be
enough for convection to occur. With WSW flow aloft, drier air
aloft will push across the FA. Although a weak subsidence
inversion aloft should be able to overcome it given the forcing
from the s/w trof. Overall, could see 30 to possibly 40 pops
given how well defined the sea breeze becomes and if any inland
progression given westerly flow aloft.

Sunday will feature the suppressed upper ridge will finally get
to expand slightly northward from the Gulf of Mexico with
continued westerly flow aloft. The sfc trof across the western
Carolinas Sat will progress to the Central Carolinas Sunday thru
Sun night. A weak s/w trof or vort is progged to move from west
to east across Central NC. How much of this forcing bleeds
southward will make a difference in the POP forecast across the

Model MOS temp consensus indicates widespread maxes in the 90s
each day, except slightly hier during Sunday. Sfc dewpoints will
also run in the low to mid 70s inland to mid to upper 70s
closer to the coast both days. How much of those upper 70s push
inland will depend on the inland progression, or lack of, of the
sea breeze. Given slightly hotter temps Sun over Sat, have
indicated that Heat Advisory Conditions will be met Sun and
conveyed this possibility in the HWO.


As of 300 PM Thursday...Ridge will be suppressed to our S Sun
and  Mon as an upper trough pivots across the Northeast states
and then offshore Tue. Shortwave energy embedded in the W to
WNW flow s of 330 AM Friday...will skirt across the Carolinas
with one spoke moving across and offshore Sun night into Mon
morning and another late Mon and Mon eve. This should help drive
a surface cold front south and into the area Mon night into
Tue. High pressure will then try to build S Tue and Wed which
should push the front further S where it will stall out Wed and

This scenario should allow for the greatest coverage of showers
and  thunderstorms early in the week, especially Mon and Mon
night when precipitable water values will peak near or in
excess of 2 inches. Convection should be scattered Sun,
initiating along the seabreeze and Piedmont trough. A greater
number of thunderstorms may arrive Sun night coincident with
upper level support which should be able to sustain upstream
thunderstorms as they move into our portion of the Carolinas.
The arrival of progressively drier air from the N Tue and Wed
should result in a decrease in convective coverage and silent
POPs may be warranted for at least portions of the area Wed and

850 mb temps will reach 20-21C Sun and so expect the heat
and humidity to still be high with high temps reaching the mid
and upper 90s. This will bring the heat index to near 105 to
109 which would require a Heat Advisory. We should be at least
a degree or two cooler Mon with more clouds and developing
convection and then seasonable temps Tue through Thu as
dewpoints lower to the mid and upper 60s which will keep heat
index values below 100 degrees. Lows Sun night will still be
muggy, mid and upper 70s, but lower 70s should be more common
for the remainder of the week.


As of 12Z...Moderate to high confidence of VFR through the TAF valid
period. Best chance for VCSH will be this morning at KILM.
Afterward the chances for convection at any terminals will be
too low to mention in TAFs.

Extended Outlook...Mostly VFR. Mainly afternoon showers and
thunderstorms each day with short duration restrictions
possible. A cold front will bring a better chance for showers
and thunderstorms Monday.


As of 330 AM Friday... Mid level ridge to our west finally
replaced by troughiness and cyclonic curvature through the
period. This will slightly energize the southwesterly flow
that has been in place due to better alignment of wind in
the vertical. With such coast- parallel flow however any
building of seas will largely be confined to areas
outside of the 20nm forecast zones.

As of 330 AM Friday...Looking at an overall forecast of SW 10 to
15 kt with occasional gusts to 20 kt. Significant seas will run
2 to 3 ft occasionally 2 to 4 ft. However, latest consensus
progs indicate a tightening of the sfc pg Sat afternoon thru the
pre-dawn Sunday hours. It`s during the mentioned time-line that
SCEC conditions will occur with SW winds increasing to 15 to 20
kt with few gusts up to 25 kt. And significant seas will
quickly follow suit and peak in the 3 to 5 foot range. No real
ground swell to talk about. Will basically contend with 4 to 6
second period wind waves thruout this period.

As of 300 PM Thursday...SSW to SW winds Sun will be mainly SW
Mon and then shift to the N and NE in the wake of a cold front
late Mon night and then NE to ENE Tue as high pressure begins to
assert a southward push across the waters. The strongest winds
will be in the range of 15 to 20 kt later Sun afternoon and eve,
the result of a robust seabreeze circulation, and into Sun
night due to some nocturnal jetting. A tightening gradient ahead
of a cold front approaching from the N may keep wind speeds
close to this range into Mon. Wind speeds will diminish to 10 kt
late Mon night. A modest push of drier and cooler air should
bring wind speeds up to around 15 kt Tue. Seas will be 3 to 4 ft
with a tendency to build to 4 to 5 ft during Tue.





NWS ILM Office Area Forecast Discussion