Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Newport/Morehead City NC
1254 PM EST Thursday Dec 18 2014
high pressure will build in from the northwest through Friday.
A weak low pressure system will move through the southeast states
Saturday then off the coast Sunday. Another weak low will move
along the southeast coast Sunday night and Monday. A stronger
system will approach from the west Tuesday with associated cold
front pushing through eastern North Carolina Wednesday.
Near term /until 6 PM this evening/...
as of 1250 PM Thursday...deck of middle/high level clouds currently
in central North Carolina should drift east through the afternoon
with skies becoming partly to mostly cloudy by late afternoon from
west to east. Current temperature forecast in good shape with
highs in the low/middle 50s most areas. No major changes to the
Short term /6 PM this evening through 6 am Friday/...
as of 330 am Thursday...short WV will move across to north overnight with some
clearing of middle and high clouds late...and another weak surface trough
passage as colder air mass continues to spread in from northwest. Min temperatures
from lower 30s inland to upper 30s obx.
Long term /Friday through Wednesday/...
as of 315 am Thursday...active pattern expected this weekend into next
week. Surface high continues to ridge into the area Friday and Friday
night...while surface low moves through the deep south. Increasing
clouds through the day Friday ahead of approaching low. Low level
thickness values support highs in the upper 40s to middle 50s. Surface
low will move off the southeast coast and strengthen late Sat and sun.
Latest guidance continues to keep the surface low weaker and further
suppressed off the coast...keeping the heavier axis of precipitation
along and just off the coast. Will continue likely probability of precipitation...though
if models continue to trend drier especially inland may need to reduce
probability of precipitation for Sat and Sat night. Will keep SC pop sun though think most
of area will be dry. Highs this weekend in the upper 40s to middle
50s...and overnight lows in the middle 30s/middle 40s. Another weak low
is expected to move along the southeast coast Sun night into Monday. Though
uncertainty remains regarding timing with European model (ecmwf) quite a bit faster
than GFS. Increased probability of precipitation for Sun night into Monday. Think area should
be drying out Monday night into Tuesday...before next batch of precipitation.
Moisture and middle/upper dynamics increase Tuesday as strong low
pressure system approaches from the west. The main low becomes
vertically stacked over the upper Midwest/Great Lakes region Tuesday
night/Wed...while a secondary low develops along the cold front
and ahead of the upper trough...moving through the Carolinas and
mid-Atlantic. One main change to previous forecast was to add
thunderstorms for Tuesday night into the first part of Wednesday...mainly along and
east of Highway 17. Models show increasing instability...with 0-6km shear
50-60kt and increased low level helicity values. Instability
should decrease quickly behind the front late Wednesday morning/early
afternoon. Though it is several days out...cannot rule out the
potential for a strong thunderstorm given the setup and strong dynamics
Tuesday night into early Wednesday. Gusty winds expected ahead of and behind
the front Wednesday with strong upper jet over the area.
Aviation /18z Thursday through Tuesday/...
short term /through 12z Friday/...
as of 1255 PM Thursday...mid/high clouds approaching from the west
and should reach the taf sites over the next 3 or 4 hours. Expect
a broken deck around 10k feet or so. The combination of this
broken deck and a 3 to 5 degree temperature/dewpoint spread should
limit fog formation tonight.
Long term /Friday through Monday/...
as of 315 am Thursday...pred VFR conditions Friday and Friday night.
Deteriorating conditions expected Sat into Monday with periods of
sub-VFR likely...with two weak low pressure systems impacting
eastern NC. At this time think best precipitation chances will be Sat and
Sat evening...then again Sun night into Monday.
short term /through tonight/...
as of 1255 PM Thursday...the earlier northerly surge has ended
with winds at or below 12 knots across the coastal waters and
sounds. Seas are in the 3 to 5 foot range with the higher seas
over the central and northern waters. Winds increase again to
10-15 knots late tonight after another surface trough passage.
Seas subside to 2-4 feet tonight.
Long term /Friday through Monday/...
as of 315 am Thursday...high pressure will continue to ridge into the
area Friday and Friday night...with north/northwesterly winds 5-15kt and seas 2-4ft.
Surface low will move through the deep south Sat...then move off the
southeast coast and strengthen late Sat and sun. Latest guidance
continues to keep the surface low weaker and further suppressed off
the coast...limiting the impacts across the waters. North/NE winds
10-20kt Sat and sun. Will continue to show seas building to
3-5ft...though could be slightly overdone. Timing remains
uncertain...but another weak low pressure system is expected to
move along the southeast coast Sun night into Monday. East/NE winds 10-20kt Sun
night becoming more southeast/southerly by Monday afternoon. Confidence is low
regarding the potential for Small Craft Advisory this weekend into early next
week...but at this time think conditions should remain just below
given latest guidance.