Area Forecast Discussion Issued by NWS Sterling, VA
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000
FXUS61 KLWX 270047
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
847 PM EDT Tue Mar 26 2024
.SYNOPSIS...
A cold front will approach the area tonight into tomorrow. An
area of low pressure will develop along the front and track off
to our northeast on Thursday into Friday. High pressure will
build to our south on Friday. Multiple weak disturbances will
track across the area this weekend into early next week.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
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A band of light to moderate showers are moving slowly through
the region this evening. Dewpoint depressions of 20 to 30
degrees is limiting the amount of measurable precipitation
observed due to theses showers. There should be a break after
theses showers exit the region before another round of
precipitation arrives around daybreak tomorrow morning.
Overnight lows will be much milder in the 40s due to increasing
cloud cover throughout the night.
.Previous Forecast
Current surface analysis shows a strong area of low pressure
tracking across the Upper Peninsula of Michigan. Water Vapor
imagery shows a broad upper trough over the Great Lakes, as
well as much of the center of the country, with a pronounced
lead shortwave attendant to the aforementioned area of low
pressure. A large fetch of moisture is steaming northward across
the Appalachians and Ohio Valley downstream of the upper
trough, with a fairly expansive stratiform rain shield in place
from Georgia northward into Ontario. The shortwave and attendant
area of low pressure will lift toward the north-northeast later
this afternoon into tonight, with the bulk of the large scale
ascent moving across the Great Lakes into southern Canada. As a
result, the shield of precipitation currently on radar off to
our west will tend to weaken and thin out as it slowly spreads
eastward through the rest of the day today into tonight.
Rain will move into the Alleghenies over the next couple hours,
and slowly expand eastward/start to fall apart through the
evening. A few sprinkles or light showers may be possible
anywhere overnight, but conditions should remain dry the bulk of
the time. Some patchy fog and/or drizzle may form toward
daybreak within light southeasterly flow. It will be a mild
night with the thick cloud cover in place. Low temperatures in
most locations will be in the 40s.-- End Changed Discussion --
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
Rain will be on the increase tomorrow morning, especially to the
east of the Blue Ridge. Chances for thunderstorms are low, but
a few elevated storms can`t be ruled out along and east of the
I-95 corridor late tomorrow morning into early tomorrow
afternoon. Overall, rainfall amounts should be fairly light
through the day tomorrow, with just a few tenths of an inch
expected. Less rainfall is expected to the west of the Blue
Ridge, but cloudy conditions will persist. Winds will remain
light out of the southeast, and high temperatures will generally
be in the 50s to the east of the Blue Ridge, with 60s further
west.
Spread in model guidance begins to increase tomorrow night as a
slow moving cold front progresses eastward across the area and
an area of low pressure develops along the front to our south.
The majority of 12z guidance has continued a southeastward
trend with the precipitation. Some solutions (such as the HRRR)
have little to no precipitation along and west of I-95 tomorrow
night, while others (such as the 12z 3km NAM) still show
substantial precipitation amounts. Most solutions now have the
heaviest rainfall confined to southern Maryland.
The front will continue to slowly progress eastward on Thursday
as low pressure deepens and tracks northeastward along the
Carolina Coast. Chances for rain will continue through at least the
morning hours and potentially into the afternoon as well,
especially to the east of the Blue Ridge. Conditions should finally
dry out by Thursday night.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
Drying conditions will settle in on Friday in the
wake of a low pressure system that will have impacted the area over
the previous few days. Pressure gradients will remain tight across
the area as a result of the low to the north and high pressure
building in across the southeastern states. Gusts may reach Wind
Advisory criteria, especially along the higher terrain. Aside from
the winds, expect mostly sunny skies with high temperatures in the
50s to low 60s (warmest across central VA and southern MD).
The area of high pressure will continue to shift further south late
Friday night into early Saturday, with a warm front moving in from
the west. This front is expected to stall around the Mid-Atlantic
and may allow for periods of rain and increasing clouds for the
weekend. With warm air advection in place, expect high temperatures
to rise into the mid to upper 60s on Saturday to even low 70s by
Sunday across a large portion of the area. It will be slightly
cooler across the higher elevations with mid to upper 50s expected.
Should the front continue to linger around the area on Monday, rain
chances may continue. Temperatures will be likely be closer to just
above normal for this time of year. Rain chances increase going into
midweek next week as an another disturbance impacts the area from
the west.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions are ongoing at most terminals this afternoon, but
an MVFR deck is holding at MTN. This MVFR deck will slowly move
westward as southeasterly flow develops, impacting BWI next, and
then all terminals by later this evening. Conditions should drop
to IFR at all terminals tonight, and remain IFR through the day
tomorrow, and likely even much of tomorrow night into Thursday.
Improvement back to VFR ceilings is expected Thursday afternoon
into Thursday night.
A few sprinkles or light showers may be possible starting this
evening, but most of the overnight hours should remain dry. Some
patchy fog and/or drizzle may also start to form during the
second half of the night. Steadier rainfall is expected tomorrow
morning at all terminals, with the steady rain lingering through
much of the afternoon at DCA, BWI and MTN. Chances for thunder
during the late morning/early afternoon hours are non-zero, but
far too low to include in the TAFs. Precipitation may redevelop
tomorrow night and continue thorough much of Thursday as a
coastal low develops off to our east. There is some east/west
uncertainty with respect to where this precipitation shield sets
up. Locations further east will have greater chances for steady
rain. Winds will generally be out of the southeast through
tomorrow, before turning out of the northwest on Thursday.
VFR conditions are expected Friday with gusty northwest winds of 25
to 35 knots possible. A weak front may approach Saturday and provide
a chance of showers and perhaps some wind gusts to around 20 kt, but
confidence remains low in CIG/VIS restrictions.
&&
.MARINE...
Winds have turned out of the southeast to east this afternoon
and are relatively light at around 5-10 knots. There may be a
slight uptick in the winds this evening to around 15-20 knots for
an hour or two. Winds will remain sub-SCA out of the southeast
through the day tomorrow. Winds will turn northerly tomorrow
night, and then northwesterly during the day on Thursday. Small
Craft Advisories may be needed for the waters in northwesterly
flow on Thursday.
Gusty northwest winds are expected Friday with a tightening pressure
gradient over the waters. Small Craft Advisories appear likely at
this time with some chances for potential gale-force winds during
the day. Advisories may continue on Saturday before the gradient
weakens over the following few days.
&&
.TIDES/COASTAL FLOODING...
Water level anomalies are around 1.5-2 feet above normal this
afternoon. While the rate of increase in anomalies has slowed,
models indicate another half to three quarters foot rise is possible
through early Wednesday as onshore flow continues. Made subtle
tweaks to the overall watches/warnings/advisories. The primary
message remains the same that fairly widespread minor to locally
moderate flooding is expected through the middle of the week. Water
levels will begin falling Thursday after a front pushes through.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
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DC...Coastal Flood Advisory until 7 AM EDT Wednesday for DCZ001.
Coastal Flood Watch from 7 AM EDT Wednesday through Wednesday
afternoon for DCZ001.
MD...Coastal Flood Advisory until 3 PM EDT Wednesday for MDZ011-016-
508.
Coastal Flood Warning until noon EDT Wednesday for MDZ014.
Coastal Flood Warning until 6 AM EDT Wednesday for MDZ017.
Coastal Flood Advisory until 7 PM EDT Wednesday for MDZ018.
VA...Coastal Flood Advisory until 3 PM EDT Wednesday for VAZ053>055-
057-527.
WV...None.
MARINE...None.-- End Changed Discussion --
&&
$$
SYNOPSIS...KJP
NEAR TERM...KJP/JMG
SHORT TERM...KJP
LONG TERM...ADS/ADM
AVIATION...ADS/KJP/ADM
MARINE...ADS/KJP/ADM
TIDES/COASTAL FLOODING...