Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
1054 am EDT Sat Aug 23 2014
a frontal boundary across the Middle Atlantic States will move southwest
of the area today. High pressure from New England slowly builds
into the area tonight into Sunday...before settling over the
Piedmont early next week.
Near term /until 6 PM this evening/...
the hrrr and RUC all indicate the showers over the SW part of the
County Warning Area will continue southeast and exit the area by early afternoon. Other
showers over Maryland will move into the Northern Neck and the Delaware-Maryland-Virginia
during the early afternoon. These will be weakening as they
encounter drier air. Have raised probability of precipitation some along the lines of both
areas of showers. Also have lowered the maximum temperature a little
as not much sunshine today and with winds coming off the ocean
will help to keep temperatures lower.
Previous discussion...latest surface analysis reveals hi pressure centered over New
England and a disorganized pressure field over the middle Atlantic region
coinciding with a weak stalled frntal boundary. Aloft...northwest flow
continues with an upper-level ridge centered over the east-central Continental U.S..
the surface front will sag S into the Carolinas today. Expect another day
with scattered shras/tstms...especially over the Piedmont closer to the
front. The potential for thunder will be confined away from the
csts due to NE flow with hi pressure building over New England. Not
expecting any severe weather but heavy rain is possible in some areas. Afternoon hi
temperatures will range from the upper 70s to near 80 over the lower Eastern Shore
to the low-middle 80s elsewhere.
Short term /6 PM this evening through Monday/...
the high surges south-southwest over the area tonight into Sunday with the
surface ridge axis settling over the Piedmont by Monday. This will
produce a drying trend along with a NE wind that should be rather
breezy along the coast. Partly to mostly sunny conditions are
expected by Sunday...with mostly clear/sunny conditions by Sunday
night and Monday.
Highs will be below seasonal averages through Monday (around -1
St dev). Highs Sunday and Monday will range from the upper 70s to
low 80s. Lows should be in the middle/upper 60s Sunday morning...with
mainly low/middle 60s expected Monday morning.
Long term /Monday night through Friday/...
surface high pressure and upper level ridging along the eastern Seaboard
is expected to continue through middle next week. This pattern will
maintain a cooler airmass over the area through Wednesday before the
ridge axes at the surface and aloft aloft begin to shift just east of
the forecast area...and moving offshore by Thursday. The forecast is generally dry
through the extended forecast periods due to well-established
subsidence through the atmospheric profile...however a few showers
cannot be ruled out near the far southeast Virginia/NE NC coast on Wednesday due to
the potential for wraparound moisture from the tropical system
passing well to the east. High and low temperatures will run below
normal from Monday night through Wednesday night (lows in the 60s...upper
50s far western counties/highs in the low-middle 80s...mid-upper 70s
beaches) and then rebound toward seasonal normals Thursday/Thursday night
(highs in the middle-upper 80s...upper 70s-lower 80s beaches/lows in
the middle-upper 60s...around 70 beaches).
Aviation /15z Saturday through Wednesday/...
kept a tempo group for -ra next few hours at kric as the batch of
rain crosses the Piedmont. Otw...high prs to the NE allowing for
dryer air along the coast with mainly VFR cndtns this am. Expect
VFR ceilings today with tsctns showing plnty of moisture around the area
for a broken SC deck (3-4k ft) through much of the forecast prd with MVFR
ceilings returning after 00z. Scattered convection possible after 18z...but
timing of any shower/tstrm problematic at this point so kept precipitation
out of forecast after 18z.
Outlook...MVFR/IFR conditions possible due to stratus/fog Sun morning.
Otw...dry weather is forecast for several days beginning Sunday.
frontal boundary now south of the area with high pressure building
south from New England. Despite the ongoing east-NE winds...latest
guidance not as bullish with the winds thus creating some doubt
when Small Craft Advisory conditions will start. Toughest call will be southern ches
Bay where only minimal conditions will be meet. Mouth of the Bay
will have an earlier start and later finish time. Seas (especially
out near 20 nm) are expected to build to 5 feet then remain there
through early next week...so extended the Small Craft Advisory headlines over the
waters through Sunday night. For continuity sake...went ahead and
hoisted Small Craft Advisory headlines for Currituck sand sun and Sun night as secondary
surge will likely keep winds between 15-20 kts.
Forecast next week will depend on the track of a developing
(tropical) low prognosticated to track NE but remain east of Gulf Stream
wall. Swell from this system will eventually affect the middle atlntc
tides prognosticated to build to about 1 foot above normal early next week
as the NE flow continues. Despite the persistant onshore flow...levels
expected to remain about 1/2 foot below minor flooding thresholds.
Went with a moderate rip current threat today given nearshore waves
of 2-3 feet and a increasing NE wind flow.
Maryland...moderate rip current risk until 8 PM EDT this evening for
NC...moderate rip current risk until 8 PM EDT this evening for
Virginia...moderate rip current risk until 8 PM EDT this evening for
Marine...Small Craft Advisory from 6 PM this evening to 2 am EDT Monday
Small Craft Advisory from 8 PM this evening to 6 PM EDT Sunday
Small Craft Advisory from 8 am Sunday to 6 am EDT Monday for
Small Craft Advisory from 8 PM this evening to 6 am EDT Monday
Small Craft Advisory from 2 am Sunday to 6 am EDT Monday for
Small Craft Advisory from 6 PM this evening to 6 am EDT Monday