Area Forecast Discussion
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FXUS62 KILM 241409
Area Forecast Discussion
National Weather Service Wilmington NC
1009 AM EDT SUN JUL 24 2016
A ridge of high pressure will expand across the Carolinas bringing
increasingly hot and humid conditions through the end of the weekend
and much of next week. Isolated showers and thunderstorms are
possible each afternoon, and heat advisories will likely be needed
each day beginning Sunday. Chance of thunderstorms should increase
heading into next weekend as ridge aloft begins to weaken.
.NEAR TERM /THROUGH TONIGHT/...
As of 1000 AM Sunday...A hot day in store across the Carolinas as
upper ridge expands across the southern tier of the CONUS. Locally,
this drives heights to 594dm and temperatures to -4C at 500mb, with
850mb temps climbing towards 20C, and easterly mid-level flow
advecting very dry air into the column. At the surface, Bermuda high
offshore will maintain warm and moist SW flow, and the conjunction
of dry air aloft and warm/moist flow near the surface will produce a
mostly sunny but hot and humid day. High temperatures are forecast
to reach well into the mid 90s, low 90s at the coast, with heat
index values expected to exceed 105 degrees everywhere this aftn. A
heat advisory remains in effect for the entire CWA.
Thunderstorms will be isolated today, if any can form at all.
Warming mid-level temps combined with the aforementioned dry air
will put a lid on updrafts this aftn/eve. PWATS have fallen to
around 1.4 inches on the morning U/A soundings, and weakening lapse
rates above 850mb will make tstm development difficult. High res
guidance suggests at least isolated activity on the sea breeze
today, and with extreme instability forecast (around 3000 J/kg of
SBCAPE), cannot rule out one or two tstms later today on the typical
summertime boundaries. Coverage will be very isolated however, and
will wane shortly after dark. Mins tonight will remain quite warm as
return flow persists, dropping only into the mid 70s.
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 330 AM Sunday...A hot and humid airmass will continue to
dominate the eastern Carolinas as a broad, flat ridge prevails
aloft and the Bermuda high persists at the surface. A thermal
trough will strengthen each afternoon over the central Carolinas.
Both days will feature afternoon heat index values exceeding 100F,
and it is possible that heat advisories will be issued for parts
of the forecast area on both days. Much like on Sunday, very dry
air aloft and lack of strong forcing will limit convective
coverage to isolated storms each day, primarily along the sea
breeze front and any other boundries that happen by. Although will
be capping pops on Tuesday to slight chance, we may see more wider
coverage of convection on Tuesday night as slightly deeper
moisture may be advecting in.
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 330 AM Sunday...Hot weather will continue as ridge holds
over the Carolinas through the mid to upper levels. Latest model
runs do not weaken the ridge until we head into next weekend when
upper trough finally pushes a cold front toward the area. Although
heights drop slightly, do not expect much change in air mass with
temps reaching into the mid 90s most days with dewpoint temps
holding in the mid 70s most places. Expect heat advisories to be
issued through at least Thurs.
As the atlantic ridge builds westward through mid week, a deeper
westerly component to the wind will aid in greater downsloping
and warmer temps, but may also help to steer clouds and upstream
convection toward the area, as well as, aid in convergence closer
to the coast. Overall expect mid levels to remain dry and warm with
limited potential for convection through Fri. Will keep mainly
isolated to sct shwrs/tstms each aftn associated with sea breeze
boundary and other localized boundaries, and along the piedmont
trough inland. Gradient will tighten heading into Friday with
stronger and gustier SW winds as ridge finally begins to break
down and cold front gets a push closer to the area. Expect
convection to kick up a notch on Saturday as mid to upper trough
digs down pushing a cold front into the Carolinas.
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
As of 06Z...A ridge of high pressure extends over the Carolinas
at the surface. A few showers just off the coast early this
morning should dissipate as the morning progresses. Expect light
SW-WSW winds to back to the S-SSW as the morning progresses,
highest wind speeds 10-15kt at the coastal terminals. Convection
could develop along the sea breeze boundary and along the piedmont
trough inland, but with dry air in the mid-levels and lack of an
upper impulse do not expect support for more than isolated
convection. Have deleted VCTS from TAFs attm.
EXTENDED OUTLOOK...Isolated to scattered afternoon convection
Tuesday through Thursday may create periods of MVFR/IFR.
Otherwise expect VFR.
NEAR TERM /THROUGH TONIGHT/...
As of 1000 AM Sunday...Bermuda high pressure remains the dominant
feature today and tonight, maintaining SW flow across the waters.
The gradient has pinched a bit from the past few days, so wind
speeds will become 10-15 kts, slightly stronger in the backed near-
shore sea breeze this aftn, before returning to around 10 kts all
waters tonight. The sea spectrum continues to feature a 2ft/8sec SE
wave and a 1-2ft/4sec SW wave, producing seas of 2-3 ft.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 330 AM Sunday...High pressure over the western Atlantic
will continue to keep winds from the S to SW at 10 to 15 kts
through the period, with seas of around 2 ft. Expect gusts up
around 20 kts each afternoon.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
As of 330 AM Sunday...Expect south to southwest winds of 10-15
knots through the period as the Bermuda High and the Piedmont
trough remain the main drivers of winds. WNA continues to show a
slight increase in seas as a longer period e-se swell diminishes
and a shorter period wind wave begins to dominate. Overall expect
seas 2 to 4 ft with a general increase heading toward the weekend
as gradient flow begins to tighten with an approach of a cold
front toward the Carolinas as ridge aloft weakens.
SC...Heat Advisory until 8 PM EDT this evening for SCZ017-023-024-
NC...Heat Advisory until 8 PM EDT this evening for NCZ087-096-099-