Area forecast discussion
National Weather Service Wilmington NC
352 PM EDT Friday may 24 2013
Synopsis...
high pressure will ridge down from the northwest bringing cool
and dry weather during the weekend. A gradual warm up begins on
Monday with seasonable temperatures expected for much of the
upcoming week. No significant rainfall is expected.
&&
Near term /until 6 am Saturday morning/...
as of 3:30 PM Friday...cool and dry northwest flow forcing dewpoints
down throughout the eastern Carolinas as Canadian high pressure
system builds in. A few tiny showers...the result of residual low
level moisture and steep lapse rates...have moved southeast across Pender
County and northern New Hanover County and then offshore. That is
about it for the day as far as precipitation GOES. The deep upper
trough responsible for the steep lapse rates will swing offshore
this evening as cool and dry air continues to pour in. Associated cumulus
field will also diminish this afternoon as the above factors come
into play.
Expect a dry and clear overnight period with record or near record
low temperatures. Forecast minimums range from the middle 40s inland to
around 50 at the coast. Record lows for may 25th are ilm-50 lbt-45
flow-48 myr-52 and cre-55. Some or all of these records may be broken
tonight.
&&
Short term /6 am Saturday morning through Sunday night/...
as of 300 PM Friday...surface high pressure ridging down from the
north and broad cyclonic flow within a longwave upper trough creates
cool and dry conditions for the weekend. While the weekend will be
pleasant with mostly sunny sky conditions other than some increased
middle level cloud cover beneath a weak shortwave late Sat
night...temperatures will struggle to 4-8 degrees below climatology for late may.
Stronger cold air advection Saturday will keep maximum temperatures only in the middle 70s even
with full sunshine. A weak surface trough associated with the passing
vorticity will turn winds briefly to the north Sat night...but a more
westerly component will develop Sunday which eases the cold air advection and helps
temperatures rise to near 80. Light winds in the cool/dry air mass will
permit decent radiational cooling Sat night...with mins falling to
10+ degrees below normal...upper 40s in the cooler spots to around
50 everywhere else. High pressure drifting offshore late in the
period creates some warmer southerly winds Sunday night...and mins
fall only into the low/middle 50s by Monday morning.
&&
Long term /Monday through Friday/...
as of 300 PM Friday...most of the country will remain fairly
active through the period with the notable exception of the
southeast...where middle level ridging will dominate especially late
in the extended forecast.
Wpc favors the European model (ecmwf) which shows an active middle level pattern across
the southwest with a meandering closed low and baroclinic zone
extending west to east well to our north. The only probability of precipitation for our area
are slight chance values late Monday across northern areas as a warm
front moves north and Tuesday before middle level ridging builds which
will all but put a lid on convection for Wednesday through Friday.
Temperature trends reflect the building ridge with at or just below
seasonal normals early trending to above climatology Tuesday and
Wednesday where they remain through the period.
&&
Aviation /20z Friday through Wednesday/...
as of 18z...there may be enough instability to kick off some
isolated showers...mainly around the Cape Fear region.
Otherwise...high confidence for VFR conditions. High pressure
building in this afternoon with gusty northwest winds. Winds
diminish this evening as gradient slackens and diurnal conditions
set up. Saturday...a beautiful day with nearly clear skies and a
moderate north wind.
Extended outlook...a slight chance for showers Sunday through
Tuesday. Morning fog possible Tuesday and Wednesday.
&&
Marine...
near term /through tonight/...
as of 3:30 PM Friday...have canceled the Small Craft Advisory for
our waters but have raised exercise caution headlines for most of
our marine zones in its place. North to northwest winds in the 15 to 20 knots
range will continue through the near term as cool Canadian high
pressure builds in. Seas will build into the 3 to 5 feet range over
the outer fringes of our waters this afternoon...otherwise expect 2
to 4 feet seas. Amz254 offshore of Horry County will stay in the 2 to
4 feet range throughout this afternoon and evening...so no headlines
for this zone.
Short term /Saturday through Sunday night/...
as of 300 PM Friday...slightly pinched gradient ahead of an
advancing high pressure at the start of the period will create north/northwest
winds of 10-15 kts early Saturday before the high moves overhead
causing much weaker wind speeds. Winds become northwest less than 10 kts
Sat night into Sunday...before veering to the southeast at less than 10 kts
Sunday night when high pressure moves offshore. Combination of light
winds and a weak 2ft/8sec southeast swell will keep wave amplitudes low
through the period...1-3 feet...highest early Saturday.
Long term /Monday through Tuesday/...
as of 300 PM Friday...the marine community can expect a
summertime pattern through the period with south to occasionally
southwest winds. Wind speeds will hover around 10-15 knots for
most of the period with the higher end Tuesday as the gradient
increases courtesy of a wave moving by well to the north. Seas are
representative of a Summer pattern as well with 2-3 feet with
mostly shorter period wind waves.
&&
Ilm watches/warnings/advisories...
SC...none.
NC...none.
Marine...none.
&&
$$
Synopsis...jdw
near term...rek
short term...jdw
long term...shk
aviation...rek/dl
marine...rek/jdw/shk
