Scientific Forecaster Discussion
fxus62 kilm 261310
Area forecast discussion
National Weather Service Wilmington NC
910 am EDT sun Mar 26 2017
above normal temperatures will prevail much of the upcoming
week as high pressure offshore brings southerly winds. A series
of low pressure systems will bring a chance of rain Monday into
Tuesday, and again late next week. A cooling trend is expected
into next weekend.
Near term /through tonight/...
as of 910 am Sunday...rally enjoying looking at the high
resolution loop of the new goesr satellite images, which show
thin streamers of cirrus overlaying a scattered to broken area
of strato-cu. Have not seen need to alter forecast for today.
Still expecting partly to mostly cloudy skies, nearly no chance
of showers and pleasantly warm temperatures in the 70s. Previous
discussion from this morning follows:
Much the same as previous day as an expansive area of strato cu
remains over off shore waters and plenty of cirrus streaming
over the Carolinas in SW flow aloft. The southeast return flow around
the ridge of high pressure over the Atlantic will push some of
these clouds on shore through the day and should see any stray
showers stay mainly over the waters. There may be some patchy
fog around just around sunrise. The cloud cover along with
plenty of warm air advection have helped to keep overnight temps close to 60.
This will give a jump start to warm day ahead. The warm air advection will
battle the cloud cover allowing temps to reach into the mid to
upper 70s this aftn.
Low pressure tracking up the Mississippi Valley will increase
the chc of pcp into the mountains and although this will not
directly affect our area, there will be increased moisture
advection in SW flow aloft. Pcp water values near .65 inches
will increase over an inch through late sun aftn. This may help
to trigger some showers over the central Carolinas and may see a
stray shower reach farther east...mainly west of I-95 late
Sunday, as well as increasing mid level clouds.
Short term /Monday through Tuesday night/...
as of 4 am Sunday...chief headline this period "warm and balmy"
and an offering of the best rain chances until late in the
week, in particular on Tuesday as a short-wave whisks overhead.
Dryish mid-level air will limit rainfall amounts and quantitative precipitation forecast output
far from stellar. The low-level heating and dewpoint fields
will continue to warrant a slight chance of a thunderstorm however, and
a few lucky folks may see higher local rainfall dumps from
convection. Pronounced drying in the mid-levels in wake of the
cold frontal passage late Tuesday night will curtail showers by
daybreak Wednesday, but no cold air follows the front.
Long term /Wednesday through Saturday/...
as of 4 am Sunday...brief high pressure intrusion via a back-
door cold front will bring a slightly cooler day on Thursday
with a lag of cooler air on Wednesday in wake of a frontal
Crossing of the coast. Thursday morning lows may end up being
the coolest portion of the week, before warm air advection
Cranks up again by Thursday night ahead of a potent southern
stream impulse. This system will offer the best rain chance of
late, and potentially a good soaking. Right now the amplified
nature of the shot-wave suggest a few strong to severe storms
cannot be ruled out late Thursday night into Friday. A few
showers may linger into Saturday beneath the cold pool of the
amplified trough, with drying and cooling through the day with
a cool morning lows in the 40s Sunday.
Aviation /13z Sunday through Thursday/...
as of 1030z...VFR conditions this taf cycle in mild and moist
weak southerly wind flow. Winds will generally be southeast to S up to
12 kts in the afternoon, otherwise 7 kts or less. An expansive
cumulus field just offshore may get guided onshore in south-southeast flow
and therefore did include a period of scattered-broken between 3-5 kft at
coastal terminals. Heating will produce some cumulus at inland
taf sites this afternoon. The mid levels will continue dry but
SW flow in the mid to upper levels will continue to feed cirrus
over the area. A few rain showers possible late inland, but not enough
in areal coverage to warrant inclusion in the tafs as of yet.
Extended outlook...flight category restrictions are possible in a
few bouts of showers and thunderstorms late Mon through Tue and
again thurs night. Expect VFR conditions after cold front moves
through on Wed lasting into thurs.
near term /through tonight/...
as of 910 am Sunday...latest obs continue to show a light S to
southeast flow with seas of around 3 ft. Forecast in good shape with no
updates needed. Previous discussion follows:
Southeasterly return flow will continue around Atlantic high
through the period. Winds will fluctuate slightly from southeast to S
remaining 10 kts or less. Winds near shore Sunday afternoon will
be a little bit higher, in the 10 to 15 kt range, and gustier
as the afternoon sea breeze circulation sets up. The persistent
southerly flow will push seas gradually but overall will remain
in the 2 to 4 ft range. Seas will remain right around the 3 ft
range through the period.
Short term /Monday through Tuesday night/...
as of 4 am Sunday...no advisories expected this period, but southeast
swell waves will keep sea heights relatively elevated given the
15 knots or less wind- speeds. Wave periods of around 10 seconds
will prevent steepness, and this will be co-joined by light to
moderate S-SW chop this period. A cold front will cross the
waters late Tuesday night accompanied by showers and isolated
thunderstorms. Patchy marine fog or mist is possible on Tuesday. A
hearty sea breeze will produce gusts to 19 knots near shore in the
afternoons. Both Mon/Tue S-SW winds 15 knots or less sustained.
Long term /Wednesday through Friday/...
as of 4 am Sunday...light winds Wednesday in wake of a cold
front can be expected, followed by a wind-shift to the n_ne
Wednesday night as a back door cold front pushes across the 0-20
nm waters. Briefly this intrusion will transition to light wind
as the high moves overhead Thursday afternoon. A strong and
progressive southern system will bring increasing southeast-S winds
late Thursday and an advisory may very well be needed for 25 knots
gusts late Thursday night ahead of its cold front. Strong storms
and numerous showers appear likely on the water Friday.