Clifton, Virginia Weather

000
FXUS61 KLWX 270030
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
830 PM EDT Fri Apr 26 2024

.SYNOPSIS...
Surface high pressure will remain situated along the East Coast
through Saturday. A warm front will lift north of the area by
Sunday. A series of fronts will cross the area during the middle
of next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Upper-level ridging will continue building in from the west
through tonight. Meanwhile, a surface high over southern New
England will begin to slide south into the western Atlantic
Ocean. Dry conditions continue as of mid evening. However,
onshore flow continues to result in clouds banked against the
central Appalachians and Blue Ridge. Clouds will gradually
expand across the area tonight as overrunning moisture and warm
advection spreads in from the southwest. Light showers will be
possible mainly west of I-81 during the second half of the
night. With the thickening clouds, overnight lows for much of
the area will be in the mid 40s to near 50. However, northeast
Maryland could drop closer to 40 as these areas will be clearer
longer.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
The surface ridge will remain along the east coast Saturday
while the mid/upper level ridge builds overhead. A perturbation
within the ridge may provide some lift, but the main contributer
to rain chances will be the advancement of the low level warm
and moist advection axis. The highest chance for greater than a
tenth of an inch of rain will be west of the Blue Ridge. Showers
will tend to fall apart to the east as they encounter a drier
airmass closer to the surface high. Thick cloud cover will limit
highs to the mid 50s to lower 60s for much of the area. Although
there could be some lingering light showers or patchy drizzle
Saturday night, most areas will be dry as the best forcing
departs. Milder temperatures in the upper 40s to mid 50s are
expected.

Deep ridging engulfs much of the Southeast and Mid-Atlantic
Sunday, bringing clearing skies and a drastic warm up. Highs
will reach the lower to mid 80s for much of the area outside of
the higher elevations and Chesapeake Bay vicinity. Some
guidance indicates potential for a stray shower or thunderstorm
to develop during the afternoon along the higher terrain, but
with weak forcing and lapse rates, any activity will be short
lived. The pattern shift will translate to overnight lows in the
mid 50s to lower 60s.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
A strong upper-level reaches its peak intensity over the region on
Monday. Additionally, high pressure is set up in prime position off
the east coast to pump in warm and moist air into the region out of
the south. This will lead to well above average temperatures, with
some ares potentially pushing for 90 on Monday along the I-95
corridor. Higher end guidance even has much of the area into the low-
mid 90s, but I would consider that a low-end probability solution.
Dew points Monday only reach the upper 50s to low 60s, so it won`t
feel quite as muggy as when we get this sort of setup during the
summertime, but still a day where staying cool and hydrated will be
important if doing work outdoors.

A weakening upper trough will lift to our northwest on Tuesday as it
ejects out of the central CONUS into the Great Lakes region. A weak
piece of shortwave energy breaks off as this happens and slides
across our region. An accompanying "cold front" will push through
and perhaps pop off some thunderstorms during the afternoon/evening
hours. The amount of instability and shear available is still very
much in question. As previously mentioned, this isn`t the muggiest
air mass, so won`t have quite as much CAPE as one would expect since
there really isn`t a direct link into the Gulf of Mexico. Wind shear
will be modest (30-40 kts of deep layer shear), but nothing too
impressive, as the shortwave moves through. Most likely initiating
source will be a pre-frontal trough in the lee of the Blue Ridge.
Forecast soundings depict an inverted-V feature in the lowest few
kilometers of the atmosphere, which would be indicative of downburst
potential with any storms that do manage to get going. Something to
watch in the coming days, but a very marginal threat at best at this
time.

A warm and unsettled pattern continues Wednesday and Thursday as
pieces of upper-level energy ride along the periphery of the
aforementioned upper ridge. High temperatures each day will be in
the mid 80s with dew points again in the upper 50s to low 60s. This
will yield similar instability values each day. However,
shear/forcing is weaker, especially on Wednesday. So severe
potential is somewhat lower that day in particular. Could see
Thursday being the next day to watch, but again it doesn`t appear to
be a slam dunk at this point in the forecast.

As always with the long term portion of the forecast, the finer
details can, and likely will, change as we move closer. So tune into
the latest forecast from our office at weather.gov/lwx.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions are expected through this evening as high
pressure to our northeast maintains dry conditions. Broken
ceilings around 5-8kft have been scattering at times but remain
prevalent from DCA to the south and west. CHO may remain
overcast through tonight. Those ceilings will lower the second
half of the night as a warm front approaches. While CHO could
drop to MVFR at times by late evening, the most likely onset
will be near or after sunrise Saturday.

The warm front will continue across the area Saturday. Showers
will be likely west of the Blue Ridge during the morning,
affecting MRB. The showers will become lighter and more
scattered as they move eastward. MVFR ceilings are likely at
CHO and MRB with a smaller chance of a period of IFR. Have
introduced MVFR cigs at IAD as well, although that may be
dependent on whether rain makes it this far east. DCA, BWI, and
MTN look to stay just east of the lower CIGs, though again it
bears watching as that could change. The system exits Saturday
night, and while VFR conditions may return overnight, the lower
clouds may linger until mixing out Sunday.

A stray shower or thunderstorm is possible near MRB Sunday
afternoon. Otherwise no significant weather expected
Sunday/Sunday night.

Southeast winds around 10 knots tonight turn south-southeast to
south Saturday, then southwest on Sunday. Could see some
occasional gusts to 15-20 knots each afternoon to evening,
especially at DCA, MTN, and BWI.

A potent upper-level ridge will keep things quiet on Monday with VFR
conditions expected. This should persist for the first half of
Tuesday as well.

Thunderstorms become a possibility by Tuesday afternoon at all
terminals. Though at this point we are only carrying chance POPs for
this period, so it is by no means a certainty. Timing would likely
be during the afternoon hours during peak heating as a pre-frontal
trough develops in the lee of the Blue Ridge.

&&

.MARINE...
Onshore/SE flow will continue through tonight. Periods of SCA
conditions are likely across most of the waters this evening.
Southeast winds are likely to result in several hours of gusts
to around 20 knots, so a Small Craft Advisory remains in effect.
After a break Saturday morning, southerly channeling is likely
to result in additional SCA winds Saturday afternoon into
Saturday night, especially on the Chesapeake Bay.

High pressure builds across the region Sunday, likely keeping
southwest winds at 10 knots or less.

Surface high pressure offshore will bring a southerly flow to the
region, which could channel up the Chesapeake Bay at times. This
could necessitate SCAs through Tuesday.

In addition to this, there will be the potential for some
afternoon/early evening thunderstorms Tuesday afternoon. Thermal
profiles are supportive of strong gusty winds with storms that do
develop, so SMWs are a possibility.

&&

.TIDES/COASTAL FLOODING...
Onshore/southeast winds will keep water levels elevated through
Saturday. The PM high tide is lower astronomically, so most
locations should remain below flood stage. Additional
advisories will likely be needed for the Saturday morning high
tide. Beyond that, additional flooding becomes less certain.
High pressure and light southwest winds may allow for gradual
draining of water from the estuary.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 2 AM EDT Saturday for ANZ530>533-
     536-538>542.
     Small Craft Advisory until 4 AM EDT Saturday for ANZ534-537-
     543.
     Small Craft Advisory until midnight EDT tonight for ANZ535.

&&

$$

SYNOPSIS...ADS/DHOF
NEAR TERM...ADS/DHOF
SHORT TERM...ADS
LONG TERM...CJL
AVIATION...ADS/DHOF/CJL
MARINE...ADS/DHOF/CJL
TIDES/COASTAL FLOODING...ADS/DHOF