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397
FXUS61 KLWX 141907
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
307 PM EDT Tue May 14 2024

.SYNOPSIS...
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Slow moving low pressure will gradually push across the Mid-Atlantic
region today through Wednesday, bringing increased chances for
showers and isolated thunderstorms as well as below normal
temperatures. Drier conditions return briefly Thursday before
another storm system brings the threat for showers and storms Friday
into the weekend. Weak high pressure tries to build back over the
area Monday with additional shower and thunderstorm chances heading
into the middle of next week.
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&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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An area of low pressure continues to progress northeastward
across the lower Ohio Valley this afternoon, with a shield of
precipitation extending into the Mid-Atlantic region. The
earlier lull in precipitation will begin to fill in with light
to moderate rainfall moving in from the Carolinas. This is a
result of a secondary low pressure off the Carolina coast that
will continue to meander further north today and into Wednesday.
Cannot rule out an isolated thunderstorm across the central and
southern portions of the area this afternoon and evening, given
some limited instability nearby. QPF totals have been increased
along the eastern slopes of the Blue Ridge and further east
along the I-95 corridor later today and into the overnight
hours. Rainfall amounts of 1 to 2" will be possible across those
areas through midday Wednesday, with lesser amounts further
west. Would not be shocked if there are some localized higher
amounts somewhere in the aforementioned area. Given these
amounts coupled with antecedent conditions, there may be an
isolated threat for flooding but it does not look to be
widespread.

Highs today will top out in the upper 60s to near 70 for most areas,
with low 60s more common in the mountains. Increased cloud coverage
has certainly dampened the chances for warmer temperatures today.
Overnight lows will drop down into the 50s with some patchy fog
possible, especially across areas that receive a lull in the
precipitation.
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&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
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The low pressure off the Carolinas will gradually move further
offshore, with the incoming low from the west building into the
area. QPF amounts will be higher in the northeast where the main
precip axis will have moved towards. Given the stabilizing
atmosphere tomorrow, expect light to moderate rain to move through
rather than convective, heavier elements. Temperatures likely remain
in the 60s for most of the area. Rain should gradually wind down
Wednesday night as the upper level trough axis passes, although low
clouds likely stick around.

Thursday and Thursday night should feature a relative break in the
action as a narrow upper ridge moves overhead and surface high
pressure wedges in from the north. However, the now-stacked low off
the coast won`t be too far away, and it`s possible clouds and a few
showers continue to rotate westward into the area. A few showers
could also form along the Alleghenies due to upslope flow. High
temperatures will likely rebound into the 70s, but this will be
contingent on cloud cover.
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&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
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A broad mid-level trough over the Central Plains Friday
moves across the TN Valley toward the Southeast/Carolina coast over
the weekend. There`s some model discrepancies regarding the exact
intensity and placement of the mid-level trough, and its associated
surface low. Most of the guidance tracks these features just south
of the area, but exactly how far is going to determine whether
higher rain chances are realized over parts of the area this
weekend.

Friday looks to start off dry as weak mid-level ridging overhead
moves east into the Atlantic. A surface high over New England will
cause keeps winds southeast to east through the weekend, though
where the surface low tracks will also impact how wind direction
changes over the area. By Sunday winds turn more northeast, then
north to northwest as a weak cold front crosses the area.

As the forecast stands, the highest rain chances look to be late
Friday night through Saturday evening as the higher PWATs and
forcing aloft are maximized over the area, and mostly along and east
of the Blue Ridge. Coverage of showers Sunday looks to be less as
the surface low moves into the Atlantic and backing winds bring in
drier air from the north. High pressure builds in Monday, possibly
bringing another day or two of mostly dry conditions.

High temperatures Friday reach their seasonal values, in the mid to
upper 70s, then drop to the upper 60s to low 70s Saturday due to
extensive cloud cover and precip. Temperatures rebound through the
start of next week, eventually reaching the low 80s. Overnight lows
settle in the mid 50s to lower 60s.
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&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
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Rain showers are continuing to overspread the area this afternoon
for the terminals. MVFR to IFR ceilings will be popular cross the
terminals this afternoon through Wednesday with the shield of
precipitation moving in. An isolated thunderstorm is possible at CHO
and MRB this afternoon into tonight, but not a high enough chance to
include in the TAF. South to southeast winds 5-10 kt expected
through tonight.

Easterly winds will build in Wednesday with low ceilings continuing.
Some light ceiling improvements may happen later in the day on
Wednesday but showers will continue through Wednesday evening before
tapering off.

There may be a break in activity on Thursday, but a few showers and
low clouds may stick around with low pressure remaining stationary
off the coast.

VFR and dry conditions to start Friday, then showers and possibly
some thunderstorms move into the area during the afternoon to
evening. Sub-VFR conditions are likely at some point Friday night
into Saturday night. At least scattered showers look to continue for
much of the day Saturday. However, there is still a lot of model
discrepancy regarding the location of a surface low to our south. If
it remains close to the area, that will bring us more rain and
longer period of sub-VFR conditions.
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&&

.MARINE...
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South-southeast winds increase once again late this afternoon and
evening, with another SCA in effect for the Chesapeake and lower
Potomac. Winds could gust slightly higher to around 24-28 knots in
the open waters of the bay during this time. Isolated thunderstorms
are possible later this afternoon into tonight.

SCAs are likely through the day on Wednesday and into Thursday for
most of the waters with low pressure nearby increasing the pressure
gradient locally. A few showers and an isolated thunderstorm will
continue to be possible through Wednesday night before tapering off.

Sub-SCA conditions could prevail for much of the day Friday into
Saturday. During this time winds are primarily east to southeast at
5-10 knots. An area of low pressure approaches from the west late
Friday into the weekend, bringing another round of widespread
showers and some thunderstorms. Depending on how close the low
pressure gets to the local waters, there could be a brief period of
SCA winds Saturday afternoon into Saturday night. This is most
likely to occur in the open waters of the Chesapeake Bay south of
North Beach. Still, there is a lot of uncertainty regarding exactly
where the surface low will track.
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&&

.TIDES/COASTAL FLOODING...
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Minor coastal flooding remains possible at high tide at sensitive
locations through at least Wednesday morning as south to southeast
winds continue. While tide levels have remained steady, or even
dropped slightly over the past 12-18 hours there is still enough of
an anomaly for Annapolis, Straits Point, and DC Waterfront to
approach or just reach minor flood stage. The increase in southerly
winds for tonight is likely to result in more abundant coastal
flooding, with Coastal Flood Advisories needed for several
locations. Coastal flood concerns diminish Wednesday night into
Thursday as northerly winds push water down the bay.
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&&

.LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 2 AM EDT Wednesday for ANZ530>532-
     539-540.
     Small Craft Advisory until 6 AM EDT Wednesday for ANZ533-534-
     537-541-543.
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&&

$$

SYNOPSIS...ADM/EST
NEAR TERM...ADS/ADM
SHORT TERM...ADS/ADM
LONG TERM...KRR
AVIATION...ADM/KRR
MARINE...ADM/KRR
TIDES/COASTAL FLOODING...LWX