Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 201019

Area Forecast Discussion
National Weather Service Wilmington NC
619 AM EDT Sun Jun 20 2021

Showers and thunderstorms will increase today into early Monday
as Claudette lifts northeast from the Southeast States to off
the OUter Banks of NC. A cold front will bring additional
unsettled weather Tuesday followed by high pressure Wednesday
and Thursday. A weak coastal trough may develop and move
onshore at the end of the upcoming work-week.


T.S. Warning has been raised for the immediate NC coast and the
adjacent waters with the worst conditions occurring tonight into
Mon morning. T.S. Watch has been raised for the immediate SC
Coast and adjacent Atl waters. This based on the latest NHC
future track and intensity of Claudette now moving ENE across
the Southeast States, poised to move across or just north of the
ILM CWA prior to pushing off the Outer Banks midday Mon.

A Flash Flood Watch is now in effect for the entire ILM CWA
due to an abundance of tropical moisture drawn northward as
Claudette approaches from the WSW. Progged PWs from soundings
indicate in excess of 2.25 inches with the NAM illustrating
hier. At the moment, have indicated widespread 2 to 3 inch
totals with isolated hier amounts possible. At this point,
Claudette will slowly accelerate as it reaches the ILM CWA and
in turn will help keep pcpn amounts from becoming a "huge"
problem. But we are dealing with tropical type rainfall which
proficiently uses the avbl moisture within the atm profile.
The rainfall on the backside of Claudette will not be as
problematic and therefore we see a quick POP decline by midday
Mon. Temps/dewpts will soon mimic a tropical system with
dewpoints already having surpassed 70 degrees. The diurnal temp
range from todays highs and tonights lows will hover around 10
degrees. Mon highs will depend on the strength of the weak mid-
level ridging in the wake of Claudette. If it`s able to help
scour out the leftover moisture due to the W to WNW flow aloft.
Have tweaked the Mon highs to upper 80s to lower 90s but not
quite as high as some MOS guidance indicates.


At this point, what was previously Claudette is now a shortwave
trough off the coast of the mid-Atlantic states. The westerlies
aloft take this feature and quickly scoot it off into the north
Atlantic. Look for a mostly dry forecast Monday night, albeit warm
and muggy, with lows only bottoming out in the mid 70s. Widespread
rain chances quickly return for Tuesday and Tuesday night, as a cold
front quickly approaches from the west. Instability does not look as
impressive here, but there does seem to be some speed shear to work
with (35-45kts), so it`s possible that there could a couple of low-
end severe concerns, particularly with wind and hail. In spite of
that, confidence is on the lower side there. Highs Tuesday in the
upper 80s to near 90, lows Tuesday night in the upper 60s to
near 70 at the coast.


Expecting a pattern change to start the long term forecast, as an
old feature returns into the fold: cold air damming (CAD) wedge.
This brings in cloud cover and cooler temperatures, with highs only
in the lower 80s in store for Wednesday and Thursday. The cold front
from the short term period is quick to move to the coast, but really
seems to stall after that, so considerably bumped up the rain
chances for Wednesday, particularly near the coast. These rain
chances relax a little more by Thursday, as the front slowly
traverses more offshore. Wedge may start to erode by Thursday
afternoon as the high pressure up north pushes offshore, but
forecast guidance doesn`t necessarily agree with that at the moment.
Friday and Saturday look more familiar for mid June, with highs in
the upper 80s and chances for convection in the afternoon, locally
driven by the Piedmont trough and seabreeze.


Heavy rain and thunder expected at ILM through around 12Z. There
may be a lull in the action through late morning as the next
batch of moisture moves in. The depresion will approach the
region this evening, with more rain and strong winds, with IFR
conditions a good bet.

Extended Outlook...Rain with embedded thunder becomes more
widespread Sun night into midday Mon due to Claudette. Expect
occasional to frequent MVFR/IFR conditions. Convection late Mon
thru Wed will not be as widespread but the threat for periodic
MVFR/IFR will continue.


Through Monday...A Tropical Storm Warning is now in effect for
the ILM NC Waters. And a Tropical Storm Watch is now in effect
for the ILM SC Waters. At the next update later this morning, it
will be determined whether to upgrade to a T.S. Warning for the
ILM SC Waters. Otherwise, the SCA for the SC Waters has been
raised for the mean time.

Conditions well ahead of Tropical Cyclone will get the local
waters stirred up today, with the main center of Tropical
Cyclone Claudette moving off the central Carolina coasts, ie.
the Outer Banks, Monday morning. The S-SW side of the cyclone`s
center will produce the strongest winds from this system, which
will be minimal T.S. Force. Timing of the strongest winds will
run from late this evening through Mon morning. Winds may lull
for a short time midday Mon but should pick back up and reach
SCA thresholds as a Lee Side trof over the Carolinas develops
which will re-tighten the sfc pg. Seas will generally be
dominated with wind driven variety likely peaking late tonight
into Mon morning then relatively hold steady thru the remainder
of the day on Mon. .

Monday Night through Thursday...
Though Claudette is physically out of the picture at this
point, winds and seas will still feel the influence.
Southwesterly winds at 20kts with gusts up to 25-30kts will
persist through Tuesday evening, easily staying in Small Craft
Advisory territory, but comfortably short of Gale Warning
territory. The seas correspond appropriately with this thinking,
with 3-4ft seas at the beaches and 5-6ft seas out 20nm from
shore. Tuesday night, southwesterly flow decreases to 10-15kts
with gusts up to 20- 25kts as seas decrease to 2-4ft. Through
Wednesday, winds veer to the NNE at 5-10kts, and the gusts
finally drop off. Seas steadily decrease a little further to
2-3ft. Seas remain consistent on Thursday, while winds continue
to veer to the SE, still sticking to 5-10kts.


SC...Flash Flood Watch from noon EDT today through Monday morning
     for SCZ017-023-024-032-033-039-054>056-058-059.
     Tropical Storm Watch for SCZ054-056.
     Beach Hazards Statement through this evening for SCZ054-056.
NC...Flash Flood Watch from noon EDT today through Monday morning
     for NCZ087-096-099-105>110.
     Tropical Storm Warning for NCZ106-108-110.
     Beach Hazards Statement through this evening for NCZ106-108.
MARINE...Small Craft Advisory until 6 PM EDT Monday for AMZ254-256.
     Tropical Storm Watch for AMZ254-256.
     Tropical Storm Warning for AMZ250-252.

MARINE...DCH/IGB is the U.S. government's official web portal to all federal, state and local government web resources and services.