National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS61 KLWX 190129 AAA
AFDLWX

Area Forecast Discussion...UPDATED
National Weather Service Baltimore MD/Washington DC
929 PM EDT Thu Apr 18 2024

.SYNOPSIS...
Low pressure will track well to our north on Friday, causing a
cold front to move through Friday night into Saturday. Thereafter,
high pressure will return for the remainder of the weekend into
early next week.

&&

.NEAR TERM /THROUGH FRIDAY/...

Marine layer is advancing westward across the eastern shore of
Maryland. Hi-res guidance shows the marine layer reaching the
western shore of the Chesapeake Bay around 02z and the Blue
Ridge Mountains around midnight. Expect cigs at or below 1kt
late tonight into Fri morning. Showers along a cold front
approaching from the west will reach the Appalachians after 15Z
and spread across the rest of the area Fri afternoon finally
exiting the area by 06Z Sat.

Previous afd...

As we move into tonight, flow at low-levels will turn easterly.
This will lead to an increasing marine influence, with low
clouds developing later tonight. Low temperatures tonight will
be in the upper 40s and lower 50s for most.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
Upper troughing will move over the Great Lakes tomorrow, while
an associated area of low pressure tracks toward Hudson Bay. The
system`s cold front will trail to the southwest across the Ohio
and Tennessee Valleys, making slow eastward progress through
the day. Warm advection will ensue at low-levels in advance of
the system`s cold front, but will have little upper support to
work with as the primary trough tracks well to our north. As a
result, showers will be possible at times, but much of the day
should remain dry. Showers will overspread areas to the west of
the Blue Ridge tomorrow morning, before progressing further
east tomorrow afternoon. Showers will continue to be possible
through much of tomorrow night until the system`s cold front
clears the area.

Cold/dry advection behind the system`s cold front will lead to
dry conditions and increasing sunshine on Saturday. High
temperatures are forecast to reach into the mid 60s to lower 70s
for most, and winds will be breezy out of the northwest, with
gusts of 20-30 mph common during the afternoon hours.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
By the end of the weekend, a frontal boundary will be situated
across the southeast with high pressure across the heart of the
CONUS. As a low continues to move along the front, expect a
chance for an isolated shower late Sunday with most areas
remaining dry. Highs will top out in the 50s to low 60s for
most, with upper 40s to low 50s in the mountains.

Continued mostly dry conditions will persist through the start of
the workweek high pressure influencing the region. Temperatures will
be at or just below normal heading into Tuesday with a slight
warming trend through the early week. By midweek, a low pressure
system will approach from the Great Lakes and bring rain chances for
the area by late Tuesday into Wednesday as a cold front passes by.
Thunderstorm chances remain low given the lack of instability across
the area during this time. Slightly below average temperatures will
persist through the remainder of the week.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Winds will turn easterly at all terminals overnight. This will
lead to a marine influence and low ceilings building back into
the area tonight. Some improvement back to MVFR is expected
tomorrow, but chances for showers will also increase tomorrow
afternoon into tomorrow night.

Sub-VFR conditions will likely continue through the first half
of tomorrow night until a cold front moves through. Behind the
front, VFR conditions and northwesterly winds are expected.
Gusts of 20-30 knots may be possible in northwesterly flow on
Saturday.

VFR conditions are expected with winds mainly out of the northwest
Sunday into Monday. No really credible rain chances are expected for
the terminals.

&&

.MARINE...
Winds over the waters will turn northerly this evening and then
pick up out of the east overnight. Small Craft Advisories are
in effect for most waters this evening through the first half of
the overnight. Winds will be light out of the east tomorrow
morning, before turning light out of the south to southeast
tomorrow afternoon. A cold front will cross over the waters
tomorrow night, causing winds to turn out of the northwest.
Small Craft Advisory conditions appear likely in northwesterly
flow on Saturday and Saturday night.

Sub-SCA winds are expected Sunday into Monday with gusts 10 to maybe
15 knots at times, especially Sunday.

&&

.TIDES/COASTAL FLOODING...
Easterly winds develop tonight then become southerly Friday,
which will result in rising anomalies. The greatest chance for
minor flooding will be along sensitive shoreline (Annapolis,
Straits Point, DC SW Waterfront) with the Friday and Friday
night high tides, although it may be close in other locations.
Water levels will drop on Saturday in gusty northwest
postfrontal flow.

&&

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

&&

$$

SYNOPSIS...KJP
NEAR TERM...LFR
SHORT TERM...KJP
LONG TERM...ADM
AVIATION...LFR/ADM
MARINE...LFR/ADM
TIDES/COASTAL FLOODING...LFR