Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington NC
319 am EDT Sat Jul 30 2016
high pressure will continue to bring oppressive heat and humidity
to the region through Saturday. The high will begin to break down
beginning Sunday. A cool front will drop slowly across the area
Tuesday into Wednesday bringing good chances for thunderstorms.
Cooler temperatures will follow for the middle and end of next
Near term /until 6 am this morning/...
as of 315 am Saturday...late night convection has weakened and
shifted off the coast and the day will begin as the last few days
with the Piedmont trough established. Precipitable water is
plentiful and the model bufr soundings are showing that deepest
moisture is along the southeast North Carolina coast. This area is
shown as where the first convection of the day will occur starting
at 16 UTC but stay along the coast counties through mid afternoon.
Models continue to show convection developing by late afternoon and
moving into the western sections of the forecast area late and
this is a plausible scenario.
The other item is that with the combination of high temperatures in
the upper 90s inland and middle 90s at the coast and dewpoints in
the lower 70s a portion of the area will fall under a heat advisory.
The counties south of a Florence to Burgaw line will see heat
indices reaching 105 to 107 degrees.
Short term /6 am this morning through Monday night/...
as of 315 am Saturday...the pattern still doesn't change much with
the Piedmont trough in place and deep moisture will continue
overhead. A cold front will approach from the north late Monday
night. The models are indicating a chance of convection throughout
most of this period. With the high precipitable waters any
thunderstorm that forms is likely to produce heavy downpours and
frequent lightning. With the increase in cloud cover, ever so
slightly cooler 850 mb temperatures, and possible convection the
high temperatures will be 2 to 3 degrees cooler on Sunday (max temps
92 to 96 degrees). This in turn will keep the heat indices just
below the heat advisory criteria.
Long term /Tuesday through Friday/...
as of 315 am Saturday...a cool down to more seasonable
temperatures is in store for the first week of August due to an
upper level trough along the eastern Seaboard and an accompanying
cool front, with highs in the upper 80's/around 90 degrees and
lows in the lower 70s through the extended. As the boundary drops
southward across the area on Tuesday, anticipate increased cloud
cover along with higher pops for showers and thunderstorms on
Tuesday and Wednesday. Latest forecast soundings highlight
precipitable water values around 1.5 and 2.0 inches, and as a
result would not entirely rule out the mention of possible heavier
downpours. Into Thursday, anticipate this boundary to weaken and
dissipate as the upper ridge expands and builds into the region.
Through the remainder of the week, expect typical summertime
Aviation /07z Saturday through Wednesday/...
as of 06z...isolated rain showers/thunderstorms and rain overnight and the potential for
patchy areas of marginal MVFR towards morning. Otherwise expect VFR
through the valid taf period with scattered rain showers/thunderstorms and rain Saturday
Latest radar imagery depicts isolated light showers moving across
the area. Do not anticipate any restrictions to arise from this
activity. With the combination of light winds and available low
level moisture from isolated showers, this may allow for patchy
areas of fog to develop towards morning, especially inland.
However, given lower confidence have not introduced into going
forecast at this time. Any fog that does develop could potentially
create marginal MVFR. After daybreak, VFR will prevail across the
forecast area with southwest winds around 10 kts, with higher
gusts and scattered convection in the afternoon. Anticipate
rain showers/thunderstorms and rain activity to taper off Saturday night, with light winds
and gradually clearing skies.
Extended outlook...isolated to scattered afternoon and evening
convection each day may result in localized MVFR/IFR conditions.
Each morning may also observe brief MVFR/IFR from fog and/or low
ceilings. Otherwise, expect VFR.
near term /through tonight/...
as of 315 am Saturday...with the surface pattern similar to
yesterday with the Piedmont trough to the west and the Bermuda high
axis to the south, winds over the water will be from the southwest
to south-southwest at 10 to 15 knots. Seas will be 2 to 3 ft today
with an occasional 4 footer 10 miles off the coast. Overnight a low-
level jet develops and the winds increase to 15 knots and seas will
rise to the 3 to 4 ft range.
Short term /Sunday through Monday night/...
as of 315 am Saturday...only change to the current pattern is a
front will shift into the northern waters just before daybreak on
Tuesday will cause the winds to increase to 15 to 20 knots on Monday
night. Seas will remain in the 2 to 4 ft range through this
forecast period. There will be a chance for thunderstorm over the
waters through this period.
Long term /Tuesday through Wednesday/...
as of 315 am Saturday...a cool front will drop southward
and gradually weaken across the waters Tuesday into Wednesday. As
a result, expect southwest winds around 10 to 15 kts
becoming northerly and then northeasterly Tuesday evening into
Wednesday,with sustained winds around 10 kts. Seas of 3 to 4 ft
on Tuesday will become 2 to 3 ft on Wednesday.
SC...heat advisory from noon today to 8 PM EDT this evening for
NC...heat advisory from noon today to 8 PM EDT this evening for