-- Discussion containing changed information from previous version are highlighted. --
082
FXUS61 KLWX 150800
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
400 AM EDT Wed May 15 2024

.SYNOPSIS...
-- Changed Discussion --
Unsettled weather conditions look to continue today as slow moving
low pressure and it`s associated front cross the region. Weak high
pressure will bring drier weather conditions to the area on both
Thursday and Friday. Another slow moving low pressure system will
bring additional shower and thunderstorm chances for the weekend
before weak high pressure returns early next week.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
One area of low pressure is near Evansville IN this morning with
a secondary low developing near Hampton Roads. Ascent with the
coastal low continues to result in light to moderate rain for
the I-95 corridor, while a dry slow moved over the western
areas. There have even been a few breaks in the clouds, so some
patchy fog is trying to form in the western valleys. Some
showers and drizzle are likely to fill back in through the
morning hours as the upper trough approaches and the coastal low
moves northeast, increasing moisture aloft.

Showers associated with the coastal low may tend to decrease
during the midday hours, but light drizzle may continue until
early evening thanks to onshore flow. Additional showers under
the upper trough may cross southwestern portions of the CWA this
afternoon. This area has the best chance for a few breaks in the
clouds and some weak instability to develop, so an isolated
thunderstorm is possible. Have removed the mention of thunder
elsewhere. Temperatures will struggle to rise under the low
overcast, with high temperatures only in the mid 60s.

The upper trough will absorb the coastal low tonight, causing it
to stall off the coast. Chances for rain will decrease, although
showers could linger near the Chesapeake closer to the low.
Skies will likely remain cloudy through the night, but there
could be some breaks in western portions of the area, leading to
fog development. Lows will be in the mid 50s to near 60.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
-- Changed Discussion --
The low will remain off the coast on Thursday while ridging
aloft attempts to build in from the west. Clouds may be slow to
clear across the I-95 corridor, but even where clouds do break,
a scattered to broken cumulus field should fill in. Most of the
day will be dry, but lingering moisture and localized
convergence could result in a few showers. Cloudier locations in
the east may struggle to reach 70, while western areas will have
highs in the mid to upper 70s. The upper ridge axis will move
overhead Thursday night, leading to dry conditions and lows in
the 50s.

The next trough will be taking a similar west to east path
across the mid Mississippi Valley on Friday. Leading axis of
forcing will approach Friday afternoon into Friday night,
bringing an increasing chance of rain. The highest chance for
showers and an isolated thunderstorm will be west of the Blue
Ridge. Temperatures will remain seasonable.
-- End Changed Discussion --

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
-- Changed Discussion --
Once again it`s another unsettled weekend with increased shower and
thunderstorm chances across the region. Our active weather pattern
continues with 1-2 days of drier weather followed by 2-3 days of
stormy conditions.

The next low pressure system and it`s associated cold frontal
boundary will approach from the Ohio River Valley Saturday into
Sunday. 00z model guidance continues to show subtle discrepancies in
regards to the placement of the low and associated surface fronts as
it pushes east. Current thinking is that the low will cut across the
central Appalachians Saturday afternoon before pushing off the VA/NC
coast Sunday.

Expect fairly widespread shower and thunderstorm activity Saturday
with decreasing coverage as the low pushes east Sunday. Severe
weather does not appear to be a concern at this point although one
or two strong thunderstorms cannot be ruled out if CAPE/shear can be
maximized within the peak heating period. This will be the case
Sunday where a few breaks in the clouds are possible (mainly over
the mountains) as drier air tries to push back in. Localized
flooding could be the bigger concern given repetitive rounds of rain
throughout the week and rich moisture (high PWATS around the 90th
percentile) funneling in. For those with plans outdoors Saturday
appears to be the wettest compared to Sunday.

Mid level ridging/weak high pressure briefly build back into the
area Monday and Tuesday bringing slightly drier conditions. Another
front and shortwave trough of low pressure will follow for Wednesday
and Thursday with renewed chances for showers and thunderstorms

Below normal high temperatures can be expected this weekend due to
added clouds and increased rain chances. Highs Saturday will push
into the mid to upper 60s with lows in the mid to upper 50s. Sunday
is slightly warmer with highs in the upper 60s and low 70s.
Temperatures rebound through the early and middle part of next week,
eventually reaching the low 80s. Overnight lows settle in the mid
50s to lower 60s.
-- End Changed Discussion --

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
Low pressure is located near Hampton Roads this morning, leading
to rain across the metro areas. A dry slot has resulted in rain
ending temporarily to the west. Standard MOS guidance has been
too pessimistic with ceilings, but do bring IFR back into the
TAFs toward dawn based on HREF probabilities. Likewise have
leaned more optimistically into MVFR conditions this afternoon
based on these probabilities. Showers may fill back in for a
time this morning, tapering more to drizzle this afternoon. One
caveat is that if drizzle is more persistent, IFR ceilings and
even visibilities could linger. Easterly winds do become more
northerly this evening, which should lead to drying conditions.
However, MVFR to IFR ceilings will likely persist with the low
lingering off the coast. Some breaks in the clouds could occur
at MRB, which could lead to fog.

Low ceilings should gradually lift Thursday and could scatter
out in some locations. However, there are indications low
ceilings and/or fog may redevelop Thursday night into Friday
morning. The next system will be approach late Friday,
increasing the chance for showers and sub-VFR ceilings,
especially Friday night.

Sub-VFR conditions can be expected through Saturday as another low
pressure system passes through the region. Shower activity will
increase across the terminals Saturday morning with perhaps a few
thunderstorms Saturday afternoon as the surface low passes to the
south. Slightly drier air and VFR conditions return Sunday into
Tuesday with weak high pressure overhead. Additional sub-VFR
conditions are possible Wednesday and Thursday next week as another
front and shortwave low pressure system cross the region.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
Low pressure is located near Hampton Roads this morning and will
gradually lift to the northeast today. Easterly winds have been
verifying on the higher side of the envelope, with gusts around
30 kt in the middle bay and lower Potomac. While not quite that
strong, forecasts do have stronger winds spreading northward
this morning. Therefore have issued a Small Craft Advisory for
all zones today except for the upper Potomac, which may be too
far west to feel these effects. Showers and drizzle may also
reduce visibility at times.

The low will remain off the coast tonight into Thursday. An
advisory will remain in effect for the bay and lower Potomac
through the night as winds become more northerly. Deeper mixing
should ensue Thursday with the wind field still in place, so the
SCA will expand to all waters. Winds are forecast to gradually
diminish Thursday night, but the advisory will likely need to be
extended for some zones. Overall lighter winds are expected
Friday and Friday night as weak high pressure moves across the
area.

A brief period of SCA conditions remain possible Saturday afternoon
into Saturday night as an area of low pressure passes just south of
the region. This will be especially true over middle and lower
portions of the bay and lower tidal Potomac where a bit more
channeling could occur. Numerous showers and perhaps a few
thunderstorms will accompany this system through Saturday into early
Sunday.

Slightly drier conditions are expected Sunday although SCA
conditions will likely remain. Winds will change from the south and
southeast Saturday to the east and northeast Sunday as low pressure
pushes off the VA/NC coast. Marginal SCA conditions will linger into
Monday as weak high pressure builds over the region.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
-- Changed Discussion --
Easterly winds will keep water levels elevated in the
Chesapeake Bay and Tidal Potomac through this afternoon. Expect
additional minor coastal flooding during this morning`s high
tide cycle at Annapolis and Straits Point, and possibly DC SW
Waterfront, although all three locations may be marginal.

As an area of low pressure moves east of the area later today, winds
become northeast, then north. This should result in quickly
decreasing water levels and reduced coastal flood threat.

Beyond today, the next threat for coastal flooding appears to be
Friday into the weekend as south to southeasterly flow returns ahead
of an approaching low pressure system from the Ohio River
Valley.
-- End Changed Discussion --

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...None.
MD...Coastal Flood Advisory from 9 AM this morning to 3 PM EDT this
     afternoon for MDZ014.
     Coastal Flood Advisory until 11 AM EDT this morning for MDZ017.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 PM EDT Thursday for ANZ530-539-
     540.
     Small Craft Advisory until 6 PM EDT Thursday for ANZ531>534-
     537-541-543.
     Small Craft Advisory from 8 AM to 6 PM EDT Thursday for ANZ535-
     536-538-542.
     Small Craft Advisory until 6 PM EDT this evening for ANZ536-
     542.
     Small Craft Advisory until 6 PM EDT this evening for ANZ538.
-- End Changed Discussion --

&&

$$

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