Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 140057
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
857 PM EDT Sun Aug 13 2017

.SYNOPSIS...
Weak high pressure will hold over the area through mid week. A
weak frontal boundary will move into the Mid Atlantic late in
the week.

&&

.NEAR TERM /THROUGH MONDAY/...
High pressure is across the Mid-Atlantic region tonight. Clear
and mainly calm conditions expected overnight. Patchy fog is
expected in low-lying areas tonight. Mid-high level clouds are
present across S WV and SW VA and will slowly move northward
overnight and into Monday morning. This will likely slow fog
from spreading and becoming more widespread into Monday morning.

Temps in the 60s and low 70s in the metros and near the waters
are expected tonight.

Clouds thicken through the day Monday as moisture returns on
backside of retreating sfc high.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
Sct showers expected Mon into Tue morning mainly over western
areas. Drying occurs on Tue afternoon and night as weak low pres
over ern NC moves offshore.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Frontal boundary will remain south of the region on Wednesday, but
warm advection will be starting already and clouds will be on the
increase again as high pressure moves east across the Northeast.
Warm front advances back across the region on Thursday with an
increased risk of showers and t-storms. By Friday, uncertainty
exists regarding speed of the wave of low pressure moving across the
Great Lakes, with faster guidance having pushed it east of the
region already, while slower guidance holds it over Quebec and
Ontario still. This uncertainty in the speed of system progression
continues Saturday, with slower guidance pushing the first system
east, while faster guidance already bringing the next system in from
the west. Sunday continues with this uncertainty, with potential for
showers and storms remaining, though some guidance now tries to
build high pressure back into the region. Bottom line is that there
is a lot of uncertainty in the long term, but it looks like the
unsettled pattern of recent weeks will be continuing. Temperatures
looks to be fairly close to normal overall, with no signicant heat
or cool swings.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
Fog possible at CHO/MRB/IAD tonight. Mid-high level clouds will
move across the terminals by Monday morning. MVFR vsbys possible
late tonight. VFR conditions expected Monday-Monday night. Low
clouds possible Tuesday morning as moisture increases northward.
Best chance for restrictions will be at CHO.

Main concern later this week will be possibility of reduced cigs and
vis with showers and thunderstorms possible Wednesday and Thursday.
Right now convection looks isolated for the most part, but could
increase to scattered coverage at some point, most likely Thursday
afternoon.

&&

.MARINE...
Winds are expected to remain below SCA through the end of the
week.

Main concern later this week will be possibility of gusty winds with
any thunderstorms Wednesday and Thursday. Risk is not high, but not
zero. Otherwise, winds likely to stay mostly below SCA criteria.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.

&&

$$
SYNOPSIS...LFR
NEAR TERM...HSK/LFR
SHORT TERM...LFR
LONG TERM...RCM
AVIATION...HSK/RCM/LFR
MARINE...HSK/RCM/LFR



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