Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Newport/Morehead City NC
444 am EST Friday Dec 13 2013
high pressure over the area will gradually move off the coast this
evening. Low pressure moving across to the west and north will push
a warm front through the area late Saturday...followed by a cold
front late Sunday. High pressure will build in from the Gulf states
the first half of next week.
Near term /until 6 PM this evening/...
as of 300 am Friday...high and dry forecast will continue today with
some increase in high clouds this afternoon. After a cold
start...building heights..offshore winds and good insolation support
maximum temperatures several degrees warmer than on Thursday...upper 40s north to
lower 50s S.
Short term /tonight/...
as of 300 am Friday...good model agreement on approaching short WV
overnight leading to increasing isent lift and coastal trough
development...resulting in thickening cloud cover and onshore surface
flow by morning. All main models have some light quantitative precipitation forecast near or over
land areas by 12z Sat...with nam12 strongest and European model (ecmwf) weakest. Went
toward weaker solution with just 20 probability of precipitation S coast late tonight. All
models agree that warming atmos at all levels...thus developing precipitation
expected to be all rain.
Indicated warming or steady temperatures overnight with thickening clouds
and onshore flow developing. Temperatures likely to drop quickly this
evening for min temperatures low-middle 30s...and increase late
Long term /Saturday through Thursday/...
as of 420 am Friday...a wet forecast in store this weekend with phasing
of northern and southern streams and low pressure developing over
the Carolina Piedmont Saturday then deepening more rapidly Saturday
night as it moves off of the middle Atlantic coast. Precipitation will
become widespread by Saturday afternoon and evening and will
continue categorical probability of precipitation those periods. Models still indicating 1
inch or more of rain possible especially for southeast areas for the
Saturday and Sunday period as the Gulf of Mexico and Gulf Stream get
tapped and precipitable water values increase to around 1.5" and eastern NC comes
under favorable region of upper divergence. Although a large portion
of eastern NC will be in the "warm sector" instability will be poor
as dewpoints are only expected to reach around 60 degrees thus not
expecting any severe weather at this time. The best chance for
surface instability will be from the Crystal Coast to the Outer
Banks. The low quickly lifts into the Canadian Maritimes sun with
deepest moisture and precipitation pushing off the East Coast. Model
consensus trending a little faster pushing the front through early
sun and even the slower model solutions have the front well offshore
with precipitation ending across eastern NC by 18z sun with rapid clearing
through the afternoon.
Temperature forecasts for the weekend will be tricky as the
surface warm front (which will be the conduit for the surface low
to move northeast along) will be slow to move northwest across
eastern NC and could take until early evening before clearing the
northwest coastal plain. Thus highs in some northern locations may
not occur until evening and there will likely be a large gradient in
temperatures from southeast to northwest. Then on Sunday the surface
cold front will likely be moving through the early in the morning
with cold air advection ramping up through the day bringing a small diurnal temperature
range...especially along the coast.
A broad eastern trough will Delaware-amplify early next week with flow
becoming more zonal by Tuesday and Wednesday with surface high pressure
building in from the west. Cool/dry weather expected early through
the middle of next week with a gradual moderation of temperatures
Aviation /10z Friday through Tuesday/...
short term /through 06z Saturday/...
as of 1230 am Friday...high and dry conditions will produce VFR
conditions through forecast period. Exception will be kpgv where patchy
steam fog may produce period of 3-5sm visibilities and brief period of IFR.
Confidence not high but enough to include in taf forecast.
Long term /Saturday through Tuesday/...
as of 420 am Friday...low pressure will track inland from the coast Sat
with good covering of rain expected bringing reduced flight categories
Saturday into Sunday. High pressure builds back over the area Monday
with dry weather and prevailing VFR expected through Tuesday.
short term /through tonight/...
as of 300 am Friday...surface high building in from west-SW will allow
offshore winds to continue at 10-15 knots over northern and central waters
this morning. Speeds expected to diminish this afternoon with 10 knots or
less for all waters most of tonight as surface high center builds across
area. Return flow southeast winds will increase to 10-15 knots over southern waters
Local nwps not available...but latest ww3 in good agreement with previous
forecast seas. Current 3-4 feet heights will subside to 1-2 feet by this
evening and continue into overnight...except building to 2-3 feet southern
waters late tonight.
Long term /Saturday through Tuesday/...
as of 420 am Friday...conditions will deteriorate rapidly Saturday as
winds increase out of the south ahead of the approaching low
pressure system. Winds expected to reach 25 to 30 knots with gusts to
around 35 knots Sat afternoon through Sat night and will raise a gale
watch for all but Albemarle Sound with the morning package. Seas
will build rapidly Sat...expecting to peak around 6 to 10 feet Sat
evening...corresponding to strongest S/SW flow. Winds will shift to
the west and north west 20 to 25 knots behind a cold front early Sunday
and north 15 to 20 knots Sunday night into Monday. The moderate
northerly flow will help to keep seas elevated at 6 feet or higher
through early Monday morning. Lighter winds Monday night into
Tuesday will lead to lower seas of 2 to 4 feet.
Marine...gale watch from Saturday afternoon through late Saturday night