Area forecast discussion
National Weather Service Wakefield Virginia
111 am EDT Friday may 24 2013
Synopsis...
a cold front will pass through the middle Atlantic overnight into
Friday morning. High pressure returns to the area late Friday into
the weekend with drier conditions and cooler temperatures
expected.
&&
Near term /through today/...
showers are waning across much of the forecast area as conditions
continue to become more unfavorable for development. A line of
thunderstorms is pushing across the Maryland Eastern Shore aided
by lift provided by a gust front. Expect heavy rain, lightning and
wind gusts to ~35mph with this line. Storms will weaken as gust
front interaction ends. Light showers/sprinkles will remain
possible through the overnight hours across eastern portions of
the forecast area. Not expecting skies to completely clear out...with moisture
still in place aloft following the surface frontal passage. Low temperatures tonight in the
low to middle 60s.
&&
Short term /tonight through Sunday/...
aforementioned middle-level trough slides through the middle Atlantic Friday
afternoon...and with decent moisture still from 950-700 mb will
maintain a 20-30% chance for showers along and east of I-95.
Overall...expect a drying trend as the trough pulls offshore and
strong cold air advection works into the area. A prtly cloudy sky in the afternoon with
noticeably cooler temperatures...highs only in the low to middle 70s.
Surface hi pressure slowly builds in from the west over the weekend as nwrly
cold air advection flow continues. Continued cooler temperatures (highs in the low to middle
70s and lows in the middle 40s to lower 50s). This is almost 10 degrees
below normal for late may.
&&
Long term /Sunday night through Thursday/...
have gone close to a European model (ecmwf)/hpc(wpc) blend with this period, which
yields only minor changes to medium range forecast. GFS has started
to catch on to ecmwf's slower solution with respect to progress of closed upper
level low over the northeast and Atlantic Canada. This slower
solution allows for a slow warmup through the period. It will also
allow for continued northwest flow across the southern middle-Atlantic Sunday
and Monday. Low (slight chance) probability of precipitation remain in place for Memorial
Day afternoon/evening and again on Tuesday as a weak disturbance/middle
level trough drops across the region while a warm front lifts north
across the Missouri/lower Ohio valleys.
By midweek, the front shunts north of the area. Middle-upper level
ridging rebuilds across the eastern half of the Continental U.S. As surface high
slides off the middle-Atlantic coast. Resultant Bermuda
high/"summerlike" setup will allow for increasing temperatures (and
humidity values) for the middle to latter part of next week. Rainfall
opportunities during this period will primarily be diurnally driven,
with little more than partly cloudy and increasingly muggy
conditions by night.
&&
Aviation /05z Friday through Tuesday/...
scattered showers and embedded thunderstorms will continue to
develop along a Lee side trough over central Virginia/NE NC this
afternoon. This in advance of a cold front...located over the
Ohio/Tennessee valleys as of 2 PM EDT. VFR/MVFR ceilings as low as 1500 to
2500 feet above ground level...with localized IFR ceilings over the lower Eastern
Shore...will prevail this afternoon. S winds generally 10 knots with
a few gusts up to 20 knots. Thunderstorm activity should mostly be
confined to inland Virginia and NC during afternoon heating. Atmosphere
remains more stable near the coast due to earlier showers and
cloud cover. Main impacts to aviation operations will be locally
heavy rainfall (mvfr/IFR visibilities possible) and gusty winds.
Thunderstorm coverage will diminish with the loss of daytime
heating...but expect scattered showers to continue tonight.
Front will cross the region tonight...clearing the coast early
Friday morning. Winds will increase from the northwest Post frontal Friday
morning and Friday afternoon. A few lingering showers will be
possible...mainly along the coast Friday morning. Otherwise...VFR
conds Friday. High pressure will then build into the region over the
weekend.
&&
Marine...
latest observation reflect general S-SW flow across the waters this
evening. Winds have begun to diminish as expected in the Bay and
sound...and have dropped Small Craft Advisory overnight with lull in Small Craft Advisory conditions
still expected. Scas now have been hoisted after 14z/Friday with
moderate cold air advection (15-25kt with gusts to 30 kt).
Good model agreement west/ developmnt/location of low pressure off
New Jersey/southern new eng coast Friday night into Sat. The low will be slow to lift to
the NE sun into Monday...resulting in only gradual improvement (sca per
wavewatch potentially to linger over the northern ocn waters into late sat).
As per policy will avoid "double headline" issuance, but additional
Small Craft Advisory flags will be necessary in the ches Bay and southern coastal
waters after current headlines expire. Period of Small Craft Advisory will be for late
Friday morning/afternoon through early Saturday. Conditions become sub-Small Craft Advisory
with winds diminishing at or below 15kt Sunday through tuesdya as high
pressure builds across the waters late in the Holiday weekend.
&&
Akq watches/warnings/advisories...
Maryland...none.
NC...none.
Virginia...none.
Marine...Small Craft Advisory from 10 am this morning to midnight EDT
tonight for anz635-636-638.
Small Craft Advisory from 10 am this morning to 6 PM EDT
Saturday for anz630>634.
Small Craft Advisory until 6 PM EDT Saturday for anz650-652-
654-656-658.
&&
$$
Synopsis...mas
near term...mam/dap
short term...mas
long term...mam
aviation...Sam
marine...mam
