Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Wakefield Virginia
648 am EDT Monday may 25 2015

Synopsis...
high pressure remains nearly stationary off the middle Atlantic
coast through Friday.

&&

Near term /through tonight/...
latest weather analysis revealing ~1028 mb surface high pressure aligned
SW to NE from the coastal Carolinas to off the Delaware-Maryland-Virginia coast.
Aloft, upper level ridge remains centered off the southeast coast.

Quiet weather continues today. Upper ridge will remain centered
off the southeast coast, but will amplify through the day. Meanwhile, surface
high will continue to slowly slide southeast through tonight. Precipitable water
values begin to creep above climatology normal today on S-southeast wind
(breezy this afternoon during peak mixing). However, subsidence beneath
the ridge will bring a dry/warm Memorial Day across the area,
with little more than a few to scattered afternoon cumulus. Thickness tools
reflecting a modest bump upward in temperatures compared to
Sunday...about a category higher on average compared to those of
yesterday. This yields highs in the 75 to 80 along the
coast...lower/mid 80s north...middle 80s south. Clear and mild
tonight west/early morning in the lower to middle 60s.

&&

Short term /Tuesday through Thursday/...
Bermuda high offshore will provide Summer-like conditions through
Tuesday through midweek. Upper ridge sliding offshore will allow for
an incremental increase in humidity Tue/Wed. A weak Lee trough
develops late Tuesday...and some scattered convection possible west of the
mountains however, airmass remains capped with convection not expected
to hold together for most of the local area. Did add a slight
chance for the far western tier of the area mainly along and northwest of
Highway 15...but otherwise maintained a dry forecast.

Upper trough ejects northeast across the upper Midwest on Wednesday/Thu,
dampening the East Coast upper ridge slightly. Resultant pressure
falls associated with weak flow aloft will sharpen Lee trough a bit
further for Wednesday afternoon. This feature...combined with increasing/advancing
moisture from the middle-south will allow for better low level convergence and
at least some forcing for some isolated to widely scattered mainly diurnally
driven convection. Have aligned 20-30 pop across the Piedmont on
Wed, mainly along/west of I-95. Chance pop across this same area again on
Thursday...with a slight chance pop installed along the coastal plain as
additional weak disturbances lift NE from the Ohio/Tennessee valleys. Severe
weather not expected during the forecast period, with shear profiles
remaining rather weak. Light steering flow would portend to a
concern for local heavy rain in any showers that develop on
Wed/Thu...but overall, expect areal coverage for showers to be
rather low through the period.

While increasing relative humidity will make it increasingly "summer-like" by the
day, look for highs each day in M-u80s west of the ches Bay...m70s-
l80s along the coast...coolest at the beaches. Early morning lows
in the 60s.

&&

Long term /Thursday night through Sunday/...
long term period will be characterized by above normal temperatures each
day and typical diurnal chances for /tstms across northwest areas.
Upper level ridge will keep fronts over the upper Midwest. Leeside
trough may trigger after thunderstorms Thursday. GFS/Euro both
indicate drying for Friday and Saturday with less coverage of
convection. Ridging weakens and the cold front to the northwest begins to
approach the area. Thunderstorm chances increase once again Sunday. High
temperatures inland range from the middle to upper 80s Thursday and
Friday increasing to around 90 Saturday and Sunday. Highs range from
80 to 85 near the coast. Lows are forecast to range from 65 to 70.

&&

Aviation /12z Monday through Friday/...
surface high pressure will persist off the eastern Seaboard through
the upcoming weekend...while middle/upper level ridging over the southeast
and Middle Atlantic States will be the dominant weather feature
through at least early Wednesday. VFR conditions will prevail
during the next 24 hours under mostly clear skies. Winds will vary
between a southeast-SW direction...becoming breezy each afternoon/early evening
during peak heating/afternoon mixing. As the middle/upper ridge axis
shifts east of the middle-Atlantic region Monday evening...expect an
influx of moisture with gradually increasing and
thickening/lowering clouds from the SW with each passing day.
Middle/upper ridging breaks down Tuesday night due to a remnant trough
passing across the western Appalachians into the Ohio Valley. This
feature will introduce showers and thunderstorms into the forecast
beginning Wednesday afternoon/evening and will allow periods of unsettled
conditions to continue through the upcoming weekend.

&&

Marine...
surface high pressure will persist off the eastern Seaboard through
the upcoming weekend...while middle/upper level ridging over the southeast
and Middle Atlantic States will be the dominant weather feature
through Tuesday. Winds will vary between a south-southeast-south-southwest direction...becoming
breezy at or below 15kt each afternoon/early evening during this timeframe.
Overall conditions will remain sub-sca...however a few gusts
could reach up to 20kt at times on the coastal waters/ches
Bay/sound. The middle/upper ridging breaks down Tuesday night due to a
remnant trough passing across the western Appalachians into the Ohio
Valley. This feature will introduce showers and thunderstorms
into the forecast beginning Wednesday afternoon/evening and will allow
periods of unsettled conditions to continue through the upcoming
weekend. Waves/seas will average 1-3ft today through Friday.
However...seas may reach up to 4ft between 10-20nm in the northern
coastal waters (north of Cape Charles light) from Tuesday night
through Thursday/Thursday night.

&&

Akq watches/warnings/advisories...
Maryland...none.
NC...none.
Virginia...none.
Marine...none.

&&

$$
Synopsis...mam
near term...mam
short term...mpr/mam
long term...lsa
aviation...bmd
marine...bmd

National Weather Service Glossary of Abbreviations