Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
953 am EDT Sat Sep 20 2014
low pressure develops off the southeast coast today and lifts north
off the Atlantic Seaboard on Sunday. A quick moving cold front
sweeps through the region Sunday night...followed by high
pressure...and cooler and drier conditions...for most of next week.
Near term /through tonight/...
middle morning update...have tweaked sky cover and probability of precipitation based upon
latest radar and satellite trends. More could cover than expected
on the Delaware-Maryland-Virginia...and increased probability of precipitation a bit across the extreme southeast
based upon latest radar. Radar data has consistently shown a
weakening trend with offshore showers as they approach the coast.
At this point...expect that trend to continue...and have only made
modest changes to probability of precipitation as a result. Forecast maximum temperatures look
good...although may have to tweak maximum temperatures across the E/se...if
cloud cover persists or thicker clouds become more widespread that
satellite trends suggest.
Early morning discussion...surface high pressure (centered off the
New England coast) will remain anchored over the local area today.
Meanwhile...low pressure will develop off the southeast coast. The
resultant easterly flow will produce a fair amount of cloud cover
across eastern areas today...while western areas will enjoy a
partly to mostly sunny Sky. High res models are in good agreement
in keeping a small chance of showers (20-25%) across far southeastern
areas today...including the coastal waters. Dry elsewhere. As far
as temperatures...pleasant readings are expected this afternoon
with highs in the middle/upper 70s to low 80s (highest inland).
For tonight...low pressure continues to lift NE off the Carolina
coast. Surface high pressure wedged in-between this feature and the
next cold front approaching from the northwest will limit small precipitation
chances (~20%) to far southeastern areas once again. Partly to mostly
clear west to mostly cloudy east. Lows in the middle 50s west to the
low/middle 60s along the coast.
Short term /Sunday through Monday/...
high pressure is expected to promote a dry and warm day Sunday
ahead of the advancing cold front from the Ohio Valley. Meanwhile...
the aforementioned coastal low quickly moves North Well off the
middle- Atlantic coast. Winds becoming west-SW in addition to 850 temperatures
climbing to around 17c Sunday afternoon should boost maximum temperatures into the
middle to upper 80s.
The cold front front will approach from the northwest Sunday
evening. The models show a very narrow band of moisture with the
front as the strongest dynamics sweep across PA. With the best
forcing to the north and limited moisture...have kept probability of precipitation in the
slight chance range Sunday night into Monday morning. After the front
clears southeastern sections of the forecast area by late Monday morning...high pressure
builds into the entire region with much drier air...and maximum temperatures
topping out between 75-80 degrees.
Long term /Monday night through Friday/...
the long term period looks to be mainly dry and uneventful with
below normal temperatures. Surface high pressure Parks over the
northeastern states middle to late week. This means a continuation of
NE to east winds which may have some marine implications. Upper level
ridging develops over the eastern Continental U.S. Late in the week.
A surface trough may develop off the Carolina coast late in the
week. Models indicate low to middle level moisture increases with some
of it spreading into our area. Slight chance showers are in the forecast eastern
Virginia/NE NC late Thursday into Friday.
Temperatures average below normal Monday night through Friday with
highs in the 70s and lows mostly in the 50s.
Aviation /14z Saturday through Wednesday/...
high pressure remains anchored along the New England coast today
as low pressure develops and moves northward off the southeast
coast. This will maintain an east-northeast wind...with speeds of 8-12kt
along the coast...and 5-8kt inland. The sky should be mainly clear
to begin the day...with 5k feet ceilings possible by this afternoon
over coastal southeast Virginia/NE NC. Low pressure continues to move northward
off the Carolina coast tonight...and off the middle Atlantic coast
Sunday. There is a slight chance of -shra over coastal southeast Virginia/NE NC
later today into tonight as the low tracks off the coast. A cold
front moves through the region Sunday night with a slight chance
-shra and/or -tsra. High pressure builds in behind the cold front
and prevails Monday through Wednesday.
update...a Small Craft Advisory was issued for the southern Chesapeake Bay from New
Point Comfort to Cape Henry until 4 PM this afternoon. A Small Craft Advisory is
also in effect for the mouth of the Bay and Currituck Sound
through 4pm this afternoon...and for the Atlantic coastal waters.
Observational data indicate Small Craft Advisory winds ~20kt east-northeast have continued to
develop over the lower Chesapeake Bay and Currituck Sound. This
should continue through midday...before slowly diminishing this
afternoon. Waves of 2 to 4 feet will occur in the Lower Bay.
high pressure will drift off the New England coast today as low
pressure develops and moves northward off the southeast coast. This
will maintain a 10-15kt east-northeast wind. The persistence of the onshore
wind will allow seas to build to 5-6ft out near 20nm. Low pressure
will continue to move north-northeast off the Carolina coast tonight.
However...the surface pressure gradient will slacken allowing the
wind to shift to north-NE and diminish to at or below 10kt. Seas should remain
~5ft and hence the Small Craft Advisory has been extended through tonight. Low
pressure races off to the NE Sunday...with the wind eventually
becoming SW by afternoon ahead of a cold front. A north-northeast wind should
continue early Sunday off the Currituck Outer Banks...so the Small Craft Advisory for
this particular zone has been extended through Sunday afternoon. The
cold front sweeps across the coast late Sunday night/early Monday
morning...with high pressure building in from the northwest Monday. High
pressure builds north of the region Monday night through Wednesday
allowing for another period of prolonged NE flow.
Maryland...Beach hazards statement until 8 PM EDT this evening for mdz025.
NC...beach hazards statement until 8 PM EDT this evening for ncz102.
Virginia...Beach hazards statement until 8 PM EDT this evening for
Marine...Small Craft Advisory until 4 PM EDT this afternoon for
Small Craft Advisory until 7 am EDT Sunday for anz650-652-654-
Small Craft Advisory until 4 PM EDT Sunday for anz658.