Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington NC
1115 PM EDT sun Apr 26 2015
a cold front will sink further south of the forecast area through
tonight. Dry high pressure will follow and move into the region
Monday and Tuesday before a storm system impacts the area late
Wednesday into Thursday. The next cold front will push across the
area Thursday...followed by seasonable and dry high pressure
Friday into next weekend.
Near term /until 6 am Monday morning/...
as of 1030 PM Sunday...elevated low topped isolated to scattered
convection to affect the area for the remainder of this evening
and early into the pre-dawn Monday hours. The actual surface cold
front...via clx radar...was located near the SC-Georgia border at this time...
and will continue to push further south overnight. Weak upward vertical velocities was
noted at the 850mb and 700mb levels across the ilm County Warning Area into the
pre-dawn Monday hours...even well behind the actual surface cold front.
Available moisture remains via latest model time height displays for
locations across the forecast area...as well as limited elevated
instability. Thus the overall activity will continue to fire but
become limited to showers...with no longer a threat from thunder.
The activity should diminish in coverage late this evening as the
the precipitation activity moves to the east-southeast at a decent clip. With surface
ridging overtakes the forecast area...albeit weak...and the forecast area becomes
more-so under the influence from middle to upper flow around the NE
states upper low. Continue to tweak tonights mins and hrly
surface dewpoints by a degree or 2. The much drier air...lower surface
dewpoints...to work their way into the ilm County Warning Area from the
north...mainly late in the pre-dawn Monday hours. Have held onto
overnight cloudiness a bit longer. Enough surface winds should keep
any fog issues at Bay.
Short term /6 am Monday morning through Tuesday night/...
as of 300 PM Sunday...cold front will be offshore Monday
morning...with cool high pressure building down behind it. While
sunshine should be abundant on Monday...cool northwest flow and 850mb temperatures
only around 3-5c will keep highs below normal once again...rising
only to around 70 during the afternoon. Cirrus level moisture will
increase late Monday...but this will have little impact to restrict
temperatures from plummeting Monday night. Weakening gradient and continued
light north winds will allow mins to drop to below 50 across most of
the County Warning Area...with mins a few degrees warmer at the beaches.
Weather begins to deteriorate slowly on Tuesday as high pressure
slips offshore and an area of low pressure develops beneath a
shortwave near the Gulf Coast. Most of the impacts from this system
should hold off until beyond the short term period...but increasing
isentropic lift atop the surface high will drive a rapidly
moistening column...and light rain showers are expected to develop
from west to east Tuesday night. Will maintain inherited low-chance pop
beginning after dark Tuesday. Highs will again be below
normal...rising to around 70...but a warmer night is expected as
cloud cover keeps lows from falling below 50.
Long term /Wednesday through Sunday/...
as of 300 PM Sunday...medium range guidance has come into better
agreement with the middle level pattern for midweek and beyond. A
cutoff low will move into the Tennessee Valley then lift slowly to
the northeast Wednesday through Friday. The surface cyclone will
move from the Florida Panhandle up the coast off of Cape Hatteras
by Thursday then out to sea Friday. I have extended the likely
probability of precipitation from Wednesday through Thursday morning. Lingering wrap
around moisture with middle level deformation warrants chance probability of precipitation
through the day Thursday but the organized activity will have
concluded by that point. 48 hour quantitative precipitation forecast amounts from wpc look
promising with an inch or so over most areas with the highest
amounts along the coast. Beyond this the middle level pattern relaxes
with surface high pressure taking control with next weekend
shaping up as dry and seasonable.
Aviation /03z Monday through Friday/...
as of 00z...MVFR ceilings are still the rule early this evening with
scattered showers. Tempo IFR visibilities will be possible in heavier
showers kmyr/kcre early this evening. Satellite loops show cloud
coverage is generally decreasing and expect showers to decrease and
MVFR clouds to slowly scattered through the evening. Middle level clouds
around 7k should scattered through the overnight hours. This layer along
with light northwest-north winds should prevent any early morning fog from
developing. If any br does develop highest confidence will be
klbt/kilm which should scattered out first. Kcre and kmyr could also have
br issues if winds get light enough due to this evenings rain. VFR
expected with northwest winds after daybreak with generally scattered low/high
Extended outlook...VFR Monday afternoon through Tuesday afternoon.
A low pressure system will move into the terminals late Tuesday
with rain and possible MVFR/IFR conditions late Tuesday evening
through Wednesday. Becoming VFR Thursday with showers ending. VFR
near term /through tonight/...
as of 1045 PM Sunday...synoptic winds are north to NE in direction
across the area waters. The local convection pushing across the
area waters may temporarily disrupt the overall synoptic
flow...especially between Cape Fear south to Little River Inlet.
This temporary wind field will likely not occur long enough to
warrant an update to the general forecast of overall north to NE
winds 10-15 knots. The overall convection has weakened to possibly
mws Worth but even that will be pushing it. Significant seas to
run 2 to 4 feet. The wind induced waves from the previous south-southwest-west-southwest
winds of the past day and a half will rule sig. Seas with
dominating periods at 7 to 8 seconds.
Short term /Monday through Tuesday night/...
as of 300 PM Sunday...cold front offshore will give way to high
pressure building in from the northwest through the early part of the
week. This high pressure will remain rather diffuse...with a weak
center passing north of the local waters...so winds will remain
rather light through the period. The exception to this will be a
brief surge Monday night when north winds will increase to 15-20
kts. Otherwise...winds will be mostly around 10 kts while veering
slowly from northwest to east. Wave heights will be highest with the
northerly surge Monday night when seas will reach 3-4 feet.
Otherwise...seas will be 1-3 feet with the primary wave group
following the veering winds.
Long term /Wednesday through Thursday/...
as of 300 PM Sunday...low pressure will move up and just off the
coast Wednesday and Thursday bringing a prolonged period of north
to northeasterly winds to the waters. Wednesday will feature
mostly northeast winds of 10-15 knots. The transition to northwest
will occur around middle morning Thursday with speeds of 10-15 knots
steady through Friday afternoon. Significant seas will remain in
check with the winds with 2-4 feet Wednesday increasing to 3-5
feet early Thursday. There could be some six footers later
Thursday across the outer waters. Seas drop off somewhat Friday.