Area Forecast Discussion
Issued by NWS Wilmington, NC
FXUS62 KILM 311920
Area Forecast Discussion
National Weather Service Wilmington NC
320 PM EDT TUE MAY 31 2016
Moisture associated with the remnants of Bonnie will be very slow
to leave the area even as the actual system finally moves northeast
of the area during Wednesday. The risk for showers and thunderstorms
will persist into the weekend as a cold front drops into the area
and stalls. The front will move offshore early next week.
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 315 PM Tuesday...Remnants of Bonnie continue to be the big
story this aftn as the center rotates slowly south of Cape Fear.
High res NSSL WRF and HRRR have done quite well displaying the axis
of heaviest rainfall which has setup across the inland Cape Fear
counties...and this will be the primary rainmaker through tonight.
Very high dewpoints combined with temps in the 80s have created a
highly unstable environment...which combined with PWAT around 1.9
inches is serving as fuel for convection with heavy rainfall. This
band of rain pivoting across the area is on an instability
gradient...and the anti-parallel vector of moisture transport to
upwind propagation is driving regeneration and heavy rainfall moving
across the same areas. This band has weakened as it "rains itself
out"...but more rain bands and tropical moisture are expected to
move back onshore and follow a similar pattern. Have carried
categorical POP for Cape Fear...ramping down to SCHC west of i-95
where instability remains high...but the atmosphere is much drier.
Much of this convection will wane with loss of heating...but
overnight tropical showers will remain a possibility although in a
weakened and less intense form.
Mins tonight will drop to a degree or two either side of 70...and
while low stratus is a near certainty everywhere...locations that
received rainfall today should also develop some fog. Local UPS fog
procedure forecasts fog primarily Horry county and NE...and this
seems reasonable where crossover temps will likely be exceeded and
the surface is most saturated. Fog potential inland is less certain
so have left out any mention inland...but light fog is still
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
As of 315 PM Tuesday...The remnants of Tropical Storm Bonnie will
continue to move very slowly to the NE this period...maintaining its
influence on the local weather. Wednesday morning...the remnants
will likely be just east of Wilmington and will drift NE to finally
exit the local coastal waters Wednesday night. As this low drifts
NE...a continued tropical airmass will support scattered showers
with heavy rainfall...but the heaviest rain should be focused NE of
the CWA on Wednesday. This is due to at least somewhat drier air
noted on today`s WV imagery and in forecast PWAT values advecting in
from the W/SW. Still...expect scattered showers with isolated
thunderstorms across the eastern third of the CWA...aided by the sea
breeze boundary as temps rise again into the low/mid 80s. There will
be more sunshine inland...but enough dry air should preclude much
convection. Most showers/tstms will wane after dark but another very
warm night is forecast with lows falling only to around 70.
The residual low pressure from Bonnie will move towards the Outer
Banks Thursday...and the driest day in some time is expected
locally. Dry air from the west...drying NW flow...and building
heights aloft will keep convection mostly capped on Thursday. Cannot
rule out isolated showers and will maintain inherited POP mostly for
sea breeze activity...but Thursday will be a much better day with
highs in the mid 80s and lows again falling to around 70 beneath
more widespread sunshine and aftn diurnal cu.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 315 PM Tuesday...The mid level pattern will continue
to evolve slowly as would be expected as we transition into the
summer months. A poorly defined west to southwest flow will be in
place through the weekend over the southeast. With precipitable
waters remaining well above 1.5 inches, the Piedmont trough will
keep good chances of showers and thunderstorms in the area for the
weekend. Difficult to distinguish what day will be wetter or
drier. There is a subtle drying of the mid levels Sunday so this
would appear to be the better (drier) of days. By Monday and
Tuesday a decent mid level trough will allow a cold front to move
across the area. A drying trend will commence as well as cooler
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
As of 18Z...The remnant low from former tropical storm Bonnie
sits about 70 miles south of wilmington. Counterclockwise winds
swirling around the low are pushing showers onshore. Now through
about 22z the best potential for flight category impacts will
exist across KCRE and KMYR where showers and t-storms are moving
in from the NE. KILM could also see some impacts this afternoon
although these inbound showers currently appear lighter in
intensity. Farther inland...KFLO and KLBT could see a VFR cumulus
ceiling with much lower chances of showers.
Mainly VFR conditions should develop this evening as showers die
away. New showers developing near the offshore low may rotate
onshore but latest models are downplaying this potential.
Beginning around 08z another low stratus cloud ceiling should
develop very similarly to this morning. This should burn off
between 13-14z Wednesday.
Extended Outlook...Mostly VFR with mainly afternoon showers and
NEAR TERM /THROUGH TONIGHT/...
As of 315 PM Tuesday...The remnant circulation of Bonnie continues
to move across the coastal waters this aftn...and will move very
slowly NE tonight. The center will remain over the coastal
waters...likely moving to a position east of Cape Fear by early
Wednesday. This is a weak system so winds will be pretty light...and
after the aftn sea breeze eases this evening winds will become more
uniform. However...the direction will be dictated by the remnant
low. Waters north of the system will experience E or NE
winds...while winds behind it will be N or NW. Speeds 10 kts or less
expected regardless of direction. The light winds will allow the SE
swell to remain dominant within the spectrum through
tonight...creating seas of 2-4 ft.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 315 PM Tuesday...Remnants of Bonnie will finally "exit stage
right"...or in this case coastal waters right...by Thursday as it
moves slowly off to the NE allowing for broad ridging to expand
across the waters on Thursday. Winds Wednesday will be dictated by
the departing storm...E/NE far NE waters...W/NW southern
waters...becoming SW at 10 kts or less all waters late. On Thursday
as the ridge expands winds will remain out of the SW...but
increasing to 10-15 kts. Seas will be generally 2-4 ft both
Wednesday and Thursday...with a SE swell dominating the spectrum
Wednesday before a southerly wind wave amplifies during Thursday.
LONG TERM /FRIDAY THROUGH SUNDAY/...
As of 315 PM Tuesday...A relatively weak pressure pattern will be in
place through the period. The gradient will tighten up a bit on
Sunday as a decent front edges closer from the west. Southwest winds
on the lower end of a 10-15 knot range will suffice for Friday and
Saturday. With the slight increase in the gradient, winds should
increase to the top end of the range. Significant seas will be 2-3
feet early increasing a bit with the winds Sunday to 2-4 feet.