Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Newport/Morehead City NC
1249 am EDT Friday Aug 28 2015
a stationary front off the coast will drift slowly east through
the weekend as weak high pressure builds into the area from the
north. Tropical cyclone Erika is forecast to be in the vicinity of
the southeast coast early next week.
Near term /until 6 am this morning/...
as of 1245 am Friday...have adjusted probability of precipitation down as most of the
activity is now offshore. Will keep just a slight chance of
precipitation along the coast overnight. Rest of forecast in
pretty good shape. Middle/high clouds will continue to prevail
overnight with low temperature forecast in the middle 60s inland to
around 70 looking good.
Short term /6 am this morning through 6 am Saturday/...
as of 240 PM Thursday...deeper moisture will gradient move further east
Friday as high pressure builds closer and the front/low offshore moves
further east. Expect dry conditions inland with a slight chance to chance
pop imd CST...espcly early. With more sun inland shld see highs
around 85 with lower 80s CST.
Long term /Saturday through Friday/...
as of 335 PM Thursday...weak zonal flow develops Friday with the
upper ridge over Bermuda building west towards the southeastern
states. At the surface, a weak front will remain stall off the NC
coast through Saturday.
Little change in forecast reasoning based on 12z guidance through
the period. The frontal boundary and deepest moisture remains
stalled offshore through Friday night and will maintain dry
conditions inland to slight chance probability of precipitation for coastal sections.
The upper ridge across the western Atlantic builds west into the
southeast Friday through early next week while a robust northern
stream shortwave moves across the Midwest into the weekend. A broad
shortwave will lift northeast around the western periphery of the
upper ridge Saturday night through Sunday, though will remain far
enough north and west of the region to have little impact. At the
surface, high pressure will shift off the middle-Atlantic coast late
Friday and ridge southwest into eastern NC Friday night into
Saturday, then transition offshore with the Piedmont trough
developing Sunday through Tuesday. Will maintain slight chance
probability of precipitation for diurnally driven, mainly isolated, shower/thunderstorm
pattern through the weekend and into Tuesday. Temperatures will
be near or a few degrees above climatology for late August.
The forecast for Wednesday and Thursday, day 7/8, is particularly
tricky due to the uncertainty in any tropical impacts from
Tropical Storm Erika, currently southeast of Puerto Rico. Will
hedge towards a model blend for this period with slight chance
probability of precipitation Wednesday increasing to chance probability of precipitation Thursday, as surface flow
shifts southeasterly and abundant moisture overspreads eastern NC.
The focus will be on the tropics this weekend as the National
Hurricane Center has Tropical Storm Erika forecast to move into
the Bahamas. Significant uncertainty continues with regards to
the strength and track of the system beyond day 3 with poor run to
run consistency in the models, thus it is too soon to speculate at
this time what impacts may be felt across the region next week.
Aviation /06z Friday through Tuesday/...
short term /through 06z Saturday/...
as of 1245 am Friday...have continued trend of VFR forecast
through the period. Middle to high clouds will prevail overnight and
with weak boundary layer mixing do not expect much in the way of
fog or stratus formation overnight. Drier air advects into the
region for Friday into Friday night with VFR conditions
Long term /Friday night through Tuesday/...
as of 340 PM Thursday...predominant VFR conditions expected
through Tuesday with only isolated, mainly diurnally driven
short term /through Fri/...
as of 1245 am Friday...gusty northeast winds over the Pamlico
Sound and some of the central and northern waters. The hrrr and
RUC are picking up well on these winds and have used a blend of
these wind fields for the very near term. Seas continue in the 3
to 5 feet range and this should persist overnight. On Friday the
high builds just to the north as the low/front drifts further east. This
shld lead to NE winds diminishing to 10 to 15 kts. The persistent
fetch will keep seas 3 to 5 feet...highest outer waters.
Long term /Friday night through Tuesday/...
as of 340 PM Thursday...the high will shift off the middle-Atlantic
coast Friday night into Saturday with winds around 15 knots or less
Saturday, diminishing to 10 knots or less by Sunday. Wind direction
will generally be northeast Saturday and Sunday, veering southeast
Sunday night then south Monday into Tuesday. Wind speeds will
become less than 10 knots Sunday night through Monday night due to
weak pressure gradient across the eastern NC coastal waters. Seas
will range 2-3 feet through the long term with some 4 feet seas for
the outer central waters. Local Swan/nwps performing better in
northeast wind/swell conditions Saturday, then a general blend
with wavewatch for the medium range. Marine interests should
continue to monitor the development of Tropical Storm Erika over
the weekend, currently located southeast of Puerto Rico.
Significant uncertainty remains with regards to forecast track and
intensity beyond day 3.