Leesburg, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

991
FXUS61 KLWX 150228
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
928 PM EST Thu Nov 14 2024

.SYNOPSIS...
A cold front will slowly cross the region through Friday morning.
High pressure will build in for the weekend before another front
crosses early to mid next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
Current water vapor imagery shows troughing and a developing
upper level low located just off to our west over the Ohio
Valley. A weakening primary low is located over northern Ohio in
the vicinity of Toledo. Meanwhile, high pressure is centered
downstream over eastern Canada, with cold air damming wedging
southward to the east of the Appalachians all the way into the
Carolinas. A coastal low is just starting to take shape
downstream of the upper trough along the North Carolina
coastline. This low will will continue to deepen as it tracks
out to sea later tonight.

Earlier overrunning precipitation has started to break up, but
showers remain scattered about the area ahead of the approaching
upper trough. Steadier rain remains across southern Maryland,
where better large scale forcing for ascent is present within
the left exit region of a jet streak situated off to our south.
Rain will continue on and off throughout the night as the core
of the upper trough closes off into an upper low as it passes
overhead. Temperatures will only drop a couple of degrees from
where they are now, with overnight lows ranging from the upper
30s in the mountains, to the 40s elsewhere.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
Gradual clearing is expected Friday (especially during the
afternoon) as low pressure pulls offshore. Some fog may be
present during the morning mainly west of US-15.

High pressure will build in from the west leading to fair
weather and moderating temperatures through the weekend.

Some areas of northeastern Maryland may receive only around a
tenth of an inch of rain. Depending on just how dry and breezy
it is, these areas could see a locally elevated fire weather
potential particularly Saturday afternoon (see Fire Weather).

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
The long term looks to largely be dry once again as a strong
upper ridge builds overhead through mid-week. This will bring
above average temperatures as well, with highs in the 60s for
most, and 50s out in the mountains. There are some indications
that the ridge could briefly break down Monday into Tuesday,
allowing a shortwave to swing by just to our north. This looks
to be the main chance for any rain, albeit very low at this
point.

On Wednesday, a pattern shift begins to take shape however, as a
deep upper trough develops across the central CONUS and moves
eastward. No impacts are anticipated in the current forecast
period, but watching late next week for a significant pattern
change across the region.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Conditions will gradually deteriorate as CIGs lower heading into
this evening, with IFR likely developing near/SW of DCA between
00Z-03Z (a couple hours early possibly for KCHO/KMRB). VSBYs
will also drop at times in moderate rain to around 2-4 SM,
perhaps briefly lower especially at KCHO/KMRB/KIAD. Winds will
remain E/NE at 5-10 kts, with a few gusts of 15-18 kts possible
at KBWI/KDCA. VFR should return by Friday afternoon as a front
clears and winds turn NW. VFR then persists through Saturday
night as NW flow gusting 15-25 kts during the day continues.

Light SW winds on Sunday will gradually turn out of the W/NW by
Monday. No significant weather is expected to impact the terminals
as high pressure will once again dominate the weather pattern.

&&

.MARINE...
East to northeast winds will persist into Friday morning,
becoming northwest Friday afternoon through Saturday. Gusts of
15 to 25 knots are expected overnight, with winds decreasing for
several hours for northern waters while holding steady or even
increasing for southern waters as low pressure strengthens
offshore on Friday. Winds increase again as low pressure pulls
away Friday night into Saturday with gusts of 20-30 kts, then
slowly diminish Saturday night as high pressure builds.

Gusty NW winds will be on the way out on Sunday morning, but SCA
conditions remain possible the first half of the day. Beyond that,
winds taper off Sunday into Monday as high pressure moves overhead.

A weak upper-level disturbance swinging through Monday night into
Tuesday could briefly kick winds back up out of the NW, which
could near SCA criteria.

&&

.FIRE WEATHER...
Most of the region will receive a quarter to half inch of rain
through tonight, with higher totals near an inch of the central
Shenandoah Valley and Allegheny/Potomac Highlands. Lower totals
of a tenth to quarter inch are anticipated over northeast MD,
where dry and breezy conditions could potentially result in a
locally elevated fire weather threat Saturday afternoon.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies will remain elevated due to onshore flow through
Friday morning, before offshore flow lowers anomalies Friday by
Friday night. Minor flooding is anticipated at Annapolis and
Washington DC SW Waterfront through Friday, with near minor
possible at several other sites until water levels recede.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Advisory until midnight EST Friday night for
     DCZ001.
MD...Small Craft Advisory until 7 AM EST Saturday for MDZ008.
     Coastal Flood Advisory until 10 PM EST Friday for MDZ014.
     Coastal Flood Advisory until 4 PM EST Friday for MDZ016.
VA...Coastal Flood Advisory until midnight EST Friday night for
     VAZ054.
     Coastal Flood Advisory until 4 PM EST Friday for VAZ057.
WV...None.
MARINE...Small Craft Advisory until 7 AM EST Saturday for ANZ530>543.

&&

$$

SYNOPSIS...DHOF/EST
NEAR TERM...KJP
SHORT TERM...DHOF/EST
LONG TERM...CJL
AVIATION...DHOF/CJL/EST
MARINE...DHOF/CJL/EST
FIRE WEATHER...DHOF
TIDES/COASTAL FLOODING...DHOF