638
FXUS61 KLWX 010000
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
800 PM EDT Sun May 31 2026
.WHAT HAS CHANGED...
The Small Craft Advisory was expanded slightly into the lower
tidal Potomac River through Monday morning. A few sprinkles may
accompany a weak disturbance late tonight into early Monday,
mainly east of the Blue Ridge Mountains. Continuing to monitor
tide levels tonight into Monday.
&&
.KEY MESSAGES...
- 1) Below normal temperatures continue through mid week, with a chance
for showers or a thunderstorm Tuesday.
- 2) More of a summertime pattern Thursday into the weekend as
temperatures warm and thunderstorm chances increase.
&&
.DISCUSSION...
KEY MESSAGE 1...Below normal temperatures continue through mid
week, with a chance for showers or a thunderstorm Tuesday.
Low pressure moving toward New England will send a cold front
southward late tonight/early Monday. The combination of
increasing high level clouds, a light southerly flow, and higher
dew points will yield a warmer night compared to the prior one.
Most areas will be in the 50s, but some outlying areas could
still drop into the 40s, especially west of the Blue Ridge. To
the east of the Blue Ridge, there are hints that there may be
just enough mid-level moisture/lift as a weak wave passes to
result in a few sprinkles overnight into early Monday.
The cold front will likely be south of the area by mid morning
Monday, with main evidence being a wind shift back to the north. Any
showers that develop along the front on Monday will likely be south
and east of the forecast area. High level clouds may become thicker
for a time. High temperatures will be fairly similar to Sunday.
Several shortwaves/vorticity maxima will deepen the trough
along the east coast Monday night into Tuesday, eventually
forming a closed low somewhere south or southeast of the area
Wednesday. As the sharpening trough axis passes overhead
Tuesday, a few showers or even an isolated thunderstorm may
develop. The highest chances will be over the mountains where
there will also be some orographic lift in the easterly low
level flow. However, there is still considerable spread in
guidance regarding just how much precipitation forms. Many
locations will likely remain dry. A surface low will eventually
form off the Carolina coast, but the position of the closed low
and strong ridging building over the Great Lakes will likely
keep any rain and clouds to the southeast. The coolest
temperatures will likely be Tuesday beneath the trough axis,
with values rising back to around normal on Wednesday.
KEY MESSAGE 2...More of a summertime pattern Thursday into the
weekend as temperatures warm and thunderstorm chances increase.
Broad 1024-1027 mb high pressure meanders over the central Apps
Thursday before shifting south and east Friday into Saturday as
upper level ridging builds over the region. This will lead to a
gradual uptick with highs each afternoon in the mid 80s to low 90s
and overnight lows in the mid 50s and low 60s. Lows Saturday night
will warm into the 60s and 70s as return flow increases ahead of the
upper level trough and resultant cold front set to sag south for the
back half of the weekend.
Meanwhile, the upper-level trough over central Canada will
continue to eject south and east with the resultant cold front
dropping down from the Great Lakes and Ohio River Valley late
Saturday into Sunday. Current 06z/12z deterministic/ensemble
suites hold the boundary to the north Saturday before allowing
it to gradually sag south Sunday into early next week. A lot of
the guidance washes the boundary out over the area Monday into
Tuesday. With the front in the vicinity of the area and pieces
of energy rippling along it, expect an increase in
showers/thunderstorms this weekend into early next week. The
severe risk appears low at this time, but some low-end
probabilities are lighting up as this system moves through (such
as CSU Machine Learning/CIPS/NSSL Probabilities and NCAR`s
Medium-Range AI Convective Hazards forecast). The timing of the
front is still subject to change given that it is a week out,
but it does hint that this associated frontal boundary will
likely be the next chance for widespread rainfall within the
region.
Highs this weekend will push into the upper 80s and low 90s with
overnight lows in the mid 60s and low 70s. Slightly cooler
conditions are expected early next week pending the placement of the
frontal boundary. Humidity will also return during the period.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
VFR conditions are expected through Monday. High pressure will
continue to drift southeast through this evening. Winds will
become southerly for a time tonight. A weak cold front will
turn winds back to the north on Monday.
Easterly winds may bring some lower clouds Monday night into
early Tuesday, but model probabilities are low at this time. A
spotty shower or thunderstorm could form Tuesday afternoon,
although the greatest chance is over the Appalachians. Winds
pivot back to the north or northeast Tuesday. VFR conditions
are likely Wednesday with continued north or northeast winds.
Prevailing VFR conditions are expected across terminals Thursday
through Sunday, with winds generally out of the west Thursday into
Friday switching to the south and southwest this weekend. Some
temporary reductions are possible Saturday and Sunday afternoon
due to thunderstorms.
&&
.MARINE...
Southerly flow will become established this evening, and
channeling will result in Small Craft Advisory conditions on the
wider waters of the middle Chesapeake Bay and lower tidal
Potomac River. It`s possible these winds may extend briefly into
other zones for a time, but will handle with MWS.
A dry cold front will push through early Monday, turning winds
out of the north once again. For at least a time in the wake of
the front, there may be a few 20-knot gusts, but it remains
uncertain if they will be widespread enough to warrant an
advisory. Increasing easterly flow Monday night will provide a
slightly greater chance of an advisory. For Tuesday into
Wednesday, the strength of north or northeast winds is a bit
uncertain. The need for advisories will likely depend on the
position and strength of an area of low pressure that will be
developing off the Carolina coast.
Winds fall back below SCA levels Thursday with some southerly
channeling over the wider waters late Friday into Saturday. Sub-
SCA level winds continue Sunday into Monday. Showers and
thunderstorms may impact mariners/boaters on both Saturday and
Sunday afternoons.
&&
.TIDES/COASTAL FLOODING...
A return of southerly flow will bring a surge in water levels
tonight/early Monday. Combined with the astronomical effects of
the full moon, guidance indicates a greater chance of minor
flooding during this period, especially in the northern portion
of the Chesapeake Bay. Annapolis may even approach moderate
flood stage. At this time, think minor stage is most likely, and
a Coastal Flood Advisory has been issued for the early Monday
high tide. Will monitor trends to determine if additional
locations need an advisory.
A cold front will lower water levels Monday, but they might
rise again toward the middle of the week depending on the
position and strength of low pressure developing off the coast.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Coastal Flood Advisory from 3 AM to 9 AM EDT Monday for MDZ014.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 9 PM this evening to 8 AM EDT Monday
for ANZ534-543.
&&
$$
DISCUSSION...ADS/DHOF/EST
AVIATION...ADS/DHOF/EST
MARINE...ADS/DHOF/EST