Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Newport/Morehead City NC
701 PM EDT Monday Apr 27 2015
high pressure will build into the area through Tuesday. Low
pressure will affect the area Wednesday into Thursday. High
pressure will build in over the weekend and remain into the
beginning of the week.
Near term /until 6 am Tuesday morning/...
as of 701 PM Monday...only change was to lower temperatures a degree or
two as current dew points in the 30s suggest a cool night. Lows in the
low 40s inland to upper 40s coast.
Weak high pressure will continue to build east into the area
tonight. A quasi- stationary vertically stacked low pressure
system will remain over the northeastern states while a strong
vortmax rotates around the western periphery of the upper low. WV
imagery shows the vortmax/shortwave is currently located across
western PA/northern WV moving south-southeast towards the region. The present
scattered diurnal cumulus field will diminish with loss of heating
early this evening, then the vortmax will move into northern
sections of the County Warning Area after midnight and become sheared west-to-
east. Moisture remains limited with forecast soundings indicating
precipitable waters falling to less than 0.50 inches. The weak shortwave moving
through the area should result in increased clouds for the
northern half of the County Warning Area overnight. Northwest winds will persist
overnight with a slight surge in speeds after midnight, mainly
becoming gusty over the coastal waters and obx late. Lows tonight
will fall into the middle 40s inland to upper 40s/low 50s along the
Short term /6 am Tuesday morning through 6 PM Tuesday/...
as of 330 PM Monday...no major changes to the synoptic players on
Tuesday with the nearly stationary vertically stacked low over the
northeastern states/Canadian Maritimes with high pressure moving
in from the west. Another upper low will move through the southern
Great Plains into the Arkansas/la/MS moving towards the region. Northerly
flow continues Tuesday with speeds diminishing late afternoon. Dry
conditions continue Tuesday under mostly sunny skies. Thicknesses
fall slightly Tuesday, to 1340-1350 meters yielding highs in the
upper 60s/near 70 across southwestern zones to low 60s across
Long term /Tuesday night through Monday/...
as of 300 PM Monday...main feature will be coastal low affecting
area Wednesday into Friday. 12z models have come into slightly
better agreement with timing of low...but still have differences
with track. European model (ecmwf) has been most consistent with track along coast
and leaned to it for forecast changes. Main adjustment was to
continue likely probability of precipitation all zones Wednesday night and extended to northern and
western sections Thursday morning.
Tuesday night...moisture and isent lift will be increasing from SW but
model hold off quantitative precipitation forecast until after 12z...and continued dry forecast. Will
see increasing clouds with min temperatures middle 40s inland to low 50s
Wednesday through Friday...upper low currently over SW US will
open up and push across southeast US as another upper low dives in from
Canada and moves across Carolinas Thursday night-Friday. Developing surface
low over northern gulfmex early Wednesday will track NE to vcty of Cape
Hatteras by Thursday afternoon...strengthening rapidly as it moves NE Thursday
night and Friday. Initial affects for eastern NC will be rain
developing Wednesday and continuing into Thursday...with upper low resulting in
continued chance of showers Thursday night and Friday. GFS indicates 1 to
2 inches across area during period while European model (ecmwf) is heaver over northern
sections with 2-3 inches there. Current forecast will remain
conservative with amounts around 1 inch given uncertainty of surface
GFS and European model (ecmwf) indicating nearly winds 25-35 miles per hour possible over coastal
sections Thursday night into Friday as low deepens offshore. Remained
conservative with forecast winds but there is increasing potential
for Wind Advisory criteria...and other coastal concerns (see
marine section)...along the coast and will mention in severe weather potential statement.
Lowered maximum temperatures Wednesday-Friday with clouds and precipitation threat expected to
limit heating...highs mainly in 60s. Lows mainly in 50s.
Friday night through Monday...high and dry forecast with ridging surface
and aloft. Temperatures still a few degrees below normal Sat...but warming
to above normal sun-Monday with highs in lower 80s inland Monday afternoon.
Aviation /00z Tuesday through Saturday/...
short term /through 12z Tuesday/...
as of 701 PM Monday...VFR conditions will prevail through the taf
period. Expect clear skies tonight through Tuesday as high
pressure builds in from the northwest. Not expecting much more than
patchy fog development possibly at kpgv as there will be a light
northwest wind and low humidities.
Long term /Tuesday night through Saturday/...
as of 300 PM Monday...VFR conditions are expected Tuesday night
into early Wednesday with weak high pressure over area. Conditions
deteriorate by Wednesday afternoon through Thursday as strengthening
low pressure moves slowly along the coast. Widespread rain will
likely lead to periods of sub-VFR ceilings and visibility. Linging chance
of showers with sub-VFR Thursday night into Friday...then drying and
VFR Friday night into Sat.
short term /tonight and Tuesday/...
as of 340 PM Monday...latest surface and buoy observations
indicate north/north-northwest winds 10-15 kts and seas 2-4 feet. A robust vorticity maximum
associated with a vertically stacked low pressure across the
Canadian Maritimes will move across the region tonight which will
serve to tighten the pressure gradient, especially after midnight.
Expect north/northwest winds to increase to 10-20 knots and possibly
briefly around 25 knots across the central and northern waters late
tonight. Seas build back to 4-6 feet north of Ocracoke Inlet but
continue around 2-4 feet to the south. Maintained scas for the surge
expected late tonight through Tuesday morning. Northerly winds
diminish 5-15 knots Tuesday afternoon with seas 2-4 feet south to 4-6
feet for the outer portions of the central and northern waters.
Long term /Tuesday night through Saturday/...
as of 300 PM Monday...light winds and seas persisting Tuesday
night...then deteriorating boating conditions likely late Wednesday into
Thursday...and rough seas may continue northern and central waters into Sat.
Surface low forecast to track SW to NE across waters late Wednesday through
Thursday...and then strengthen as it moves to NE Thursday night and Friday.
Models still differ on forecast track but have better agreement on
timing with low near Cape Hatteras Thursday afternoon. Remained conservative
with wind forecast as low track across area given forecast
uncertainty...but did increase winds Thursday night and Friday to at
least 20-25 knots.
12z GFS and European model (ecmwf) indicate 25-35 knots nearly winds over waters Thursday
night and Friday...which would result in threat of high
surf and coastal flooding...and will mention in severe weather potential statement.
Used nwps for seas through Thursday night...then blend of previous forecast
and ww3 Friday-Sat resulting in forecast of 7-10 feet seas northern and central
waters Thursday night into Friday. If models continue to trend with
higher winds on backside of low...seas could be at least 3-5 feet
Marine...Small Craft Advisory from 4 am to 1 PM EDT Tuesday for amz150-