Forecast Discussion
000
FXUS61 KLWX 200800
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
400 AM EDT Sat Apr 20 2024
.SYNOPSIS...
A cold front will move through the area this morning. High
pressure will build into the area tonight into early next week.
Low pressure will track to our north on Wednesday, causing
another cold front to move through the area.
&&
.NEAR TERM /THROUGH TONIGHT/...
A cold front is near the Appalachian crest this morning while a
separate area of low pressure is located over the Carolinas.
Showers have recently become more pronounced along the I-95
corridor, with some patchier light rain and drizzle still
lingering to the west. While current showers are showing a
steady eastward motion, some additional showers will be possible
along the I-95 corridor due to the slow progression of the front
and low passing by to the south.
The clearing line will progress eastward today, with most areas
seeing plenty of sun by early-mid afternoon. As pressures
finally begin to rise this afternoon, expect an increase in
northwest winds with gusts in the 20-30 mph range (locally
higher in the mountains). The downslope flow will promote
warming and drying, with highs ranging from the mid 60s to mid
70s in the lower elevations.
The front will stall well to our south tonight while high
pressure builds eastward from the plains. High level clouds will
begin to increase ahead of troughing aloft. Colder air will
continue to advect into the area, and overnight lows will range
from the mid 30s to lower 40s, with below freezing temperatures
in the higher elevations of the Alleghenies. While some patchy
frost is possible, especially west of the Blue Ridge, the
clouds, lingering light winds, and relatively large dew point
spreads lower confidence.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Low pressure will ride along the front well to our south on
Sunday while a narrow ridge of high pressure continues to extend
eastward from the Plains. Most guidance continues to keep rain
south of the area, but there are still some northern solutions
that bring some light rain from central Virginia to far southern
Maryland. Abundant mid and high level clouds will be in place
area wide and it will be much cooler. Highs will be in the mid
50s to lower 60s with 40s in the higher elevations. The lows to
our south and over eastern Canada will depart Sunday night,
allowing high pressure to finally build eastward. Skies will
clear, and guidance has a better signal for radiational cooling.
The only question mark in regards to frost is wind, which may
remain around 5 mph out of the west. Lows will be in the 30s for
most, except warmer in the urban centers. Besides the higher
elevation, there is also potential for subfreezing temperatures
in the central Shenandoah Valley.
High pressure will build atop the area Monday and Monday night.
Mostly clear skies are expected with temperatures slightly below
average. Patchy frost could form again Monday night in sheltered
valleys, but overall the airmass will start moderating by that
time.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
High pressure will influence dry conditions and near average
temperatures on Tuesday. Highs should reach the upper 60s to the
lower 70s.
The high will move east to allow for a cold front to approach
Tuesday night before passing through the region during the day on
Wednesday. There is a chance for rain showers later Tuesday night
and during the day Wednesday with respect to the passing front. High
temperatures on Wednesday will be near average but a few degrees
cooler than Tuesday. As the front passes each respective area later
Wednesday, a downsloping component to the wind could squash
additional chances of rain or lessen the effect from rain showers.
On the other hand, an upslope component will influence rain shower
chances along the western ridges.
A second area of high pressure builds in behind the departing cold
front Thursday with a reinforcing third high expected on
Friday. The second high will usher in cooler and drier air on a
gusty west to northwest breeze. The third area of high pressure
will solidify dry and cool conditions going into the end of the
week. Highs will be a couple of degrees below average Thursday,
but should rebound a couple of degrees on Friday.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
Low ceilings and showers remain across the area early this
morning as a cold front slowly approaches from the west. Most
areas are teetering between MVFR and IFR, with gradual
improvement toward daybreak as winds shift to the west. VFR
conditions should return by mid morning and showers will push to
the east. NW winds will increase this afternoon, with gusts of
20-25 kt expected. Winds will gradually diminish this evening.
Impacts with low pressure will likely remain south of the
terminals Sunday, although there will be mid/high level
ceilings. High pressure will build in Sunday night-Monday night
with no significant weather expected.
VFR conditions Tuesday through Tuesday evening. Sub-VFR conditions
possible Tuesday overnight and during the day Wednesday with
possible showers developing with a cold frontal passage. Winds
increasing south 10 to 15 knots gusts to 20 knots Tuesday into
Tuesday night. Winds southwest becoming northwest around 15 knots
gusts 20 to 25 knots Wednesday and Wednesday night.
&&
.MARINE...
Winds are currently sub-SCA level over the waters. A cold front
will move through early this morning, causing winds to turn
northwesterly in its wake. SCAs are in effect this afternoon for
most of the waters, expanding to all waters this evening as a
surge of winds pushes southward. Winds will decrease the second
half of the night.
Low pressure will pass south of the area Sunday and winds will
largely remain sub-SCA in nature, but some gusts could come
close across northern waters. A pressure surge Sunday night
could result in SCA conditions on the bay. Lighter winds are
expected Monday and Monday night as high pressure builds across
the area.
Small craft advisories are likely Tuesday afternoon through
Wednesday evening. Winds south 10 to 15 knots gusts up to 20 knots
Tuesday afternoon and Tuesday night. Winds southwest becoming
northwest 15 to 20 knots gusts higher Wednesday and Wednesday night.
&&
.TIDES/COASTAL FLOODING...
Tidal anomalies have already started to decrease. Besides the
headlines for the current high tide cycle, additional advisories
appear unlikely as water levels continue to decrease as
northwest winds take hold later today.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Advisory until 9 AM EDT this morning for DCZ001.
MD...Coastal Flood Warning until 8 AM EDT this morning for MDZ014.
Coastal Flood Warning until 4 AM EDT early this morning for
MDZ017.
Coastal Flood Advisory until 4 AM EDT early this morning for
MDZ018.
VA...Coastal Flood Advisory until 9 AM EDT this morning for VAZ054.
WV...None.
MARINE...Small Craft Advisory from noon today to 2 AM EDT Sunday for
ANZ530-535-536-538.
Small Craft Advisory from noon today to 6 AM EDT Sunday for
ANZ531-532-539-540.
Small Craft Advisory from 4 PM this afternoon to 6 AM EDT
Sunday for ANZ533-541-542.
Small Craft Advisory from 8 PM this evening to 6 AM EDT Sunday
for ANZ534-537-543.
&&
$$
SYNOPSIS...ADS
NEAR TERM...ADS
SHORT TERM...ADS
LONG TERM...KLW
AVIATION...ADS/KLW
MARINE...ADS/KLW/KJP
TIDES/COASTAL FLOODING...ADS
