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603
FXUS61 KLWX 181854
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
254 PM EDT Sat May 18 2024

.SYNOPSIS...
Low pressure will drift off the Carolina Coast through the weekend.
High pressure will build overhead Monday into Tuesday. A cold front
will approach from the Midwest Wednesday, then cross by Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
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As an upper shortwave moves off to the northeast, and a
secondary shortwave moves toward the Southeast coast, moderate
showers from this morning have departed. Behind the main swath
of moderate rain, scattered showers linger. Ceilings and
visibility quickly rebounded behind the exiting rain shield,
but MVFR and lower conditions have redeveloped thanks to
previous rainfall and ongoing showers. Some thinning of the
cloud cover is evident on satellite this morning, with even a
few breaks developing between the Allegheny Ridge and the Blue
Ridge. Currently expect this clearing to expand slightly further
east as we head into the afternoon, but likely no significant
clearing further than the Blue Ridge. High temperatures in these
areas may rise a few degrees than previously forecast.

Some guidance suggests lowering cigs/fog tonight within a few
hours of sunrise, primarily for DCA and westward. Have hinted at
this in the TAFs for DCA and IAD, and explicitly mentioned for
MRB and CHO with higher confidence. Coverage of spotty showers
decrease through the evening.
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&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
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Sunday starts off with cloud cover over most of the area, with
possible breaks along our western periphery similar to today.
Shower activity on Sunday appears to be less than previously
forecast since the system responsible has made a swift exit and
high pressure builds in from the north, but a few showers and
isolated thunderstorms can`t be ruled out in the afternoon quite
yet, primarily west of the Blue Ridge. Cloud cover will
decrease through the day and high temperatures are expected to
reach into the 70s for much of the area. Low temperatures will
be in the 50s. With available moisture from recent rainfall and
high pressure moving in, some fog could develop late Sunday
night into Monday morning.

Monday begins our reprieve from unsettled conditions with dry
weather and sunny skies in the forecast. High temperatures rise
to the mid-upper 70s, starting a warming trend as well.
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&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
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A broad upper level ridge is forecast to be remain in place over the
eastern seaboard on Tuesday with high pressure at the surface. A
southerly return flow will lead to increasingly warming
temperatures through the middle parts of next week. The SFC high
pressure on Tuesday will keep the region dry, but an approaching
cold front from the west will bring increasing chances for showers
and thunderstorms Wednesday through Friday. Model guidance has
trended slower with the mid-week system and there remains some
uncertainty if there will be enough instability (CAPE) that overlaps
with the favorable period for shear to produce a threat for severe
weather. SPC is focusing on the Ohio Valley for SVR weather
Wednesday into Thursday, but the CIPS machine learning model
continues to suggest that there is a chance for isolated severe
weather in our region during the middle and later parts of next
week.
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&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
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Ceilings and visibility quickly rebounded behind the exiting
rain shield, but MVFR and lower conditions have redeveloped
thanks to previous rainfall and ongoing showers. Some guidance
suggests further lowering of cigs/fog tonight within a few hours
of sunrise, primarily for DCA and westward. Have hinted at this
in the TAFs for DCA and IAD, and explicitly mentioned for MRB
and CHO with higher confidence. Coverage of spotty showers
decrease through the evening.

Conditions should improve to VFR by late morning/early afternoon
on Sunday as high pressure builds in.

VFR conditions are favored Tuesday through Friday with winds likely
to be out of the south to southeast.  Brief aviation restrictions
will be possible with shower and thunderstorms Wednesday through
Friday.
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&&

.MARINE...
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SCAs remain in effect for our southern waters and the lower
tidal Potomac from 5PM this afternoon through 6AM Sunday
morning. E/SE winds become N/NE by Sunday morning. High pressure
builds in on Sunday and winds remain sub-SCA and out of the E/NE
through Monday.

Sub-SCA conditions are favored on Tuesday, but a southerly
channeling flow on Wednesday may require Small Craft Advisories.
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&&

.TIDES/COASTAL FLOODING...
Persistent onshore flow (albeit light) is expected to persist into
early next week. Repeated rounds of flooding are possible,
especially along vulnerable shoreline. Given the light nature of the
flow, flooding should stay in the minor realm.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
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DC...Coastal Flood Advisory from 3 PM to 7 PM EDT Sunday for DCZ001.
MD...Coastal Flood Advisory from 1 PM to 4 PM EDT Sunday for MDZ014.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 5 PM this afternoon to 6 AM EDT
     Sunday for ANZ534-537-543.
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&&

$$

SYNOPSIS...DHOF
NEAR TERM...CAS
SHORT TERM...CAS
LONG TERM...JMG
AVIATION...JMG/CAS
MARINE...JMG/CAS
TIDES/COASTAL FLOODING...DHOF