Scientific Forecaster Discussion
fxus62 kilm 231413
Area forecast discussion
National Weather Service Wilmington NC
1013 am EDT Wed Oct 23 2019
high pressure will bring fairly seasonable temperatures through
Friday. A storm system will approach over the weekend bringing
a gradual increase in rain chances.
14z surface analysis shows high pressure centered over the mid-
south, accompanied by very dry air. The high will lift towards
the mid-Atlantic today and tonight as a mid-level trough digs
across The Rockies. Light northerly surface flow will keep Max
temps just a few degrees below climo today, otherwise abundant
sunshine is on tap. No changes needed to going forecast at this
time. Across the coastal waters, northerly winds of 15-20 kt
will diminish to 10-15 kt as the pressure gradient weakens this
afternoon, and seas will consist primarily a northerly 3-4 ft
wind wave every 4-5 seconds.
Near term /through Thursday/...
no pops or any type of weather to contend with this period.
The secondary cold front passage has pushed thru during these pre-dawn Wed hrs with
the cold air advection surge now encompassing the ilm County Warning Area. This follows on the
heels of late last evening after the main cfp, in which the forecast area saw
winds veer westerly at 5 to 10 mph, which advected drier air, ie.
Lower dewpoints, across the forecast area. Few/sct stratocu early this morning
will dissipate leaving mainly thin cirrus moving overhead, under west-southwest-
SW jetstream flow thru the remaining near term period. Center of sfc
high will elongate across the Carolinas from the Gulf Coast states
late today and tonight. The center will progress across and off the
mid-Atlantic states by Thu evening. The cold air advection will be quick and become
neutral this aftn thru Thu. Could see a decent rad cooling night
tonight and will hedge lows slightly lower than the consensus of
various model MOS guidance. Max temps Thu will nearly be the same
for what occurs today, possibly a degree or 2 milder than today with
full insolation and neutral adv. Return flow around the high
departing off the mid-Atlantic states could push stratocu toward and
possibly onshore especially south of Cape Fear but not enough to
curtail mostly sunny Thu fcst.
Short term /Thursday night through Friday night/...
high pressure will be shifting off the mid-Atlantic coast thurs
night through Fri, while extending back into the Carolinas. In
the mid to upper levels, ridge to the east will maintain west-SW
flow aloft. Low pressure system over the western Gulf will
deepen as shortwave dig down toward the lower Mississippi
Valley and cuts off. The deep west-SW flow aloft will carry
moisture from this system across the southeast in the way of
increasing mid to high clouds on Fri, but ridge will maintain a
good bit of dry air and subsidence aloft. Low level flow will
shift slowly around from the NE to east with an increasing moist
flow off the Atlantic as wedge of high pressure holding on.
Expect increase of low clouds into Fri night under fairly steep
subsidence inversion aloft. Overall, air mass will begin to warm
with increasing clouds through Fri into Fri night, but any
significant pcp should hold off as system to the west begins to
lift northward. Temps will be influenced by increase in clouds
and moisture. High on Fri should reach into the mid 70s most
Long term /Saturday through Tuesday/...
storm system will lift rapidly northward from the lower
Mississippi Valley to the Ohio Valley, reaching New England by
Sunday. At the same time, high pressure will continue to wedge
in from the northeast while ridge aloft holds just to our east.
Expect more in the way of low clouds into Saturday with
increasingly deep moist flow heading into the latter half of
the weekend as system moves rapidly off to the northeast. Expect
clouds to increase and thicken with increasing chc of pcp in
deeper moisture return from the Gulf ahead of trailing cold
front Sat night into Sunday. Temps will warm into early next
week with above normal temps expected, especially with
increased clouds and moisture present.
Cold front should drop south but should linger just south as
wave of low pressure develops along it as another shortwave digs
down toward the Gulf Coast. This could leave unsettled weather
over the area, or at least a portion of the area into the middle
of next week.
Aviation /14z Wednesday through Sunday/...
high confidence for VFR conditions through the forcast period. High
pressure will build in today, with north northwest winds becoming
northeast and diminishing tonight. Only passing cirrus is expected.
Extended outlook...mainly VFR with possible MVFR/IFR from fog and/or
low stratus Fri and Sat mornings...and from pcpn and clouds ahead of
a cold front during sun.
cold air advection surge under offshore west-northwest-north-northwest winds will dominate today,
with a few gusts up to 25 kt this morning due to the surge
across SSTs in the 70s. Not enough occurrence to invoke a Small Craft Advisory.
The short period wind driven seas that built up under southeast-S flow
yesterday, will get knocked back down rather quickly today. An
underlying 2 foot east-northeast-east wraparound swell around 10 second
periods will become dominant late tonight thru Thu with some
weak wind chop on top. The center of high pressure will track
across the Carolinas tonight and off the coast of the mid-
Atlantic states during Thu. This will keep a semi-tightened sfc
pg across the ilm waters that will keep winds semi-active,
around 10 kt tonight and Thu except 10- 15 kt for the
southernmost portions of the local waters Thu.
Northeasterly winds thurs night into Fri will become more
onshore as high pressure continues to extend into the waters
from the north to northeast as it tracks east off the mid
Atlantic coast. Winds will eventually become southerly as storm
system to the west lifts off to the north dragging a cold front
eastward through the end of the weekend. Seas will remain less
than 3 ft heading into the weekend, but should increase by the
latter half o the weekend into early next week in increasing
southeasterly push ahead of approaching cold front. Seas may
reach up to 3 to 5 ft by late Sunday.