Area Forecast Discussion
Issued by NWS Wilmington, NC
FXUS62 KILM 290742
Area Forecast Discussion
National Weather Service Wilmington NC
342 AM EDT SUN MAY 29 2016
Rain will stay in the area through Tuesday until the tropical
system makes its slow departure. Moisture will hang around for
most of the week so while sunshine should return in part there
will still be a scattering of storms each day. A cold front will
approach next weekend.
.NEAR TERM /THROUGH TONIGHT/...
As of 300 AM Sunday...A Tropical Storm Warning is in effect for the
South Carolina coast. Weak Tropical Storm Bonnie was located about
190 miles south of Myrtle Beach and as of the last report was moving
slowly to the north. As was the case last night...all of the
convection was located NW and N of the actual center. There is
virtually no cold cloud tops/significant convection in the vicinity
of the center. This is indicative of a sheared environment. Also,
dry air to the south of the center, across FL and coastal GA was
getting advected northward and into the system. These conditions
should continue to hinder any strengthening.
Bonnie is expected to be very near the coast near CHS late this
morning and early this afternoon. Steering flow remains weak, but
Bonnie is expected to be guided northward through tonight as
upstream upper level trough moves toward the coast and western
Atlantic ridge builds near Bermuda. This may result in Bonnie
hugging the upper South Carolina coast.
Regardless of the exact track and lack of organization, the expected
weather conditions will be the same. High precipitable water values,
around 2 inches in deep east to southeast flow will necessitate high
pops. The potential for bouts of heavy rain in waves of showers and
a few thunderstorms streaming in from off the Atlantic. This may
cause localized ponding. ENE to E winds will generally become ESE or
SE today. Wind speeds will be 10 to 15 mph...but up to 15 to 25 mph
across the South Santee River area and as far north as the southern
Grand Strand. Winds will be strongest later this afternoon and into
the eve hours.
A weak tornado can not be ruled out, mainly early today when the low-
level flow will exhibit the greatest veering with height.
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 300 AM Sunday...Bonnie may be a tropical depression before the
start of the period. The system or its remnants will be in the area
through the period as it moves slowly up along the Carolina coast.
The current forecast track has it lifting north of the Cape Fear
area Tue night. This will keep the weather unsettled, but drier air
and subsidence will eventually reach the area. Thus, would expect a
greater coverage of showers and thunderstorms throughout Mon with
coverage perhaps shrinking inland on Tue, but still high along the
coast. We are still forecasting total rainfall amounts in the 2 to 3
inch range although higher amounts will be possible.
Thick cloud cover Mon will be shrinking from W to E Tue and Tue
night and this will result in slightly warmer temps inland on Tue.
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 3 AM Sunday... The moisture directly associated with Bonnie
should be out of the picture by Wednesday. Sufficient moisture will
remain for scattered showers and storms however especially if some
upper troughiness remains behind. Rain chances should arguably wind
up just a bit higher over northern zones. No more mid level trough
on Thursday but a poorly defined surface pressure pattern will
remain. The sea breeze and outflow boundaries should still manage to
produce appreciable coverage of mainly diurnal storms. The former
should make good progress inland. Rain chances then rise a bit
Friday and maybe moreso Saturday as the next upper trough and
surface cold front approach from the north and west.
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
As of 06z...Tropical Storm Bonnie is nearly stationary about 200
miles south of Myrtle Beach...and as this tropical storm lifts very
slowly NW...periods of MVFR/IFR are expected at all terminals.
Rainfall has been mostly offshore so far tonight...but bands
continue to develop and angle towards the coast. The rain has been
primarily light...but MVFR vsbys with IFR cigs are expected at times
overnight...highest confidence at CRE/MYR. Timing the exact onset
and dissipation of IFR is nearly impossible so have handled this
with a TEMPO group at the coastal terminals. Inland...cigs are
forecast to gradually lower to IFR even though rainfall will be
less...and have a predominant IFR cig group at LBT/FLO...however
confidence is low.
After daybreak IFR cigs will lift...but periods of showers and MVFR
will persist as TS Bonnie lifts slowly towards the area. Winds will
increase...especially near the coast...with gusts up to 20 kts
possible from the E/SE. Attm do not expect an all-day rain...but
periods of showers will be frequent through the day. More MVFR/IFR
is possible late Sunday night as the column remains highly saturated.
Extended Outlook...Unsettled weather through Thursday with possible
SHRA/isolated TSRA and TEMPO MVFR/IFR conditions.
NEAR TERM /THROUGH TONIGHT/...
As of 300 AM Sunday...A tropical Storm Warning is in effect for the
southern waters and a Small Craft Advisory is in effect for the
northern waters. The strongest winds are expected this afternoon and
this eve as Bonnie slowly lifts northward along the coast. Wind
speeds across the southern waters should peak in the 20 to 25 kt
range...perhaps up to 30 kt as stronger winds to our south creep
north. Winds across the northern waters will be 15 to around 20 kt.
The wind direction will be ESE to SE. The wind direction will veer
to the SSE and S tonight. Seas will be mainly 5 to 7 ft. A brief
waterspout or two can not be ruled out today.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 300 AM Sunday...Bonnie may be a tropical depression by the
start of the period. The depression or its remnants will slowly lift
north along the upper South Carolina coast and the southeast North
Carolina coast...perhaps lifting north of the Cape Fear waters Tue
night. This will keep showers and thunderstorms across the waters
for much of the period. South winds will hold across the waters Mon
and Mon night. As what is left of Bonnie lifts slowly away from the
area Tue and Tue night...winds should come around to a more NW or N
direction. Seas will be 4 to 5 ft Mon, subsiding to 3 to 4 ft by Tue
and then 2 to 3 ft Tue night.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
As of 3 AM Sunday... Decreasing wind and seas through the period as
tropical system moves off to the north and east. Wednesday`s wind
direction forecast may need some refining as there is still guidance
that stalls the system very near the area until then. Not so by
Thursday at which time the system`s exit will bring a west wind
that will then back to southerly as west Atlantic high pressure
SC...Tropical Storm Warning for SCZ053>056.
High Rip Current Risk through this evening for SCZ054-056.
NC...High Rip Current Risk through this evening for NCZ106-108-110.
MARINE...Tropical Storm Warning for AMZ254-256.
Small Craft Advisory until 10 PM EDT Monday for AMZ250-252.