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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 200758
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
358 AM EDT Mon May 20 2019

.SYNOPSIS...
A cold front will cross the area this afternoon and early
evening. Sprawling Canadian high pressure will dominate in its
wake through the middle portion of the work week. This high will
shift offshore Wednesday night as a frontal boundary lingers
near the Mid Atlantic to finish out the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Low pressure over the Great Lakes early this morning is
stretching a cold front on the doorstep of the Ohio Valley, as a
stationary boundary is kinked along the Mid Atlantic seaboard.
Skies overhead are partly cloudy with the bulk of shower
activity north of the Mason Dixon Line. Temperatures remain
quite mild this morning, hovering in the middle 60s over our
mountain zones, with low to middle 70s being observed elsewhere.
Dewpoints in the low to middle 60s continue to give that
summer-like feel in the air.

The aforementioned cold front will track eastward through the
Ohio Valley this morning, crossing into the CWA this afternoon
through early this evening. Guidance in fairly good agreement of
any shower/storm activity associated with its passage to be
mainly focused along and east of the Blue Ridge mountains. This
is where the best CAPE (1000-1500 J/kg) and shear resides, but
overall instability will be down compared to the past couple of
days. The threat for a few strong to marginally severe storms
does exist east of the Blue Ridge into the metro areas,
including southern MD. The primary threat with any strong storm
that develops along the front will be locally damaging winds
and hail. Temperatures are expected to soar well into the 80s,
but likely a degree or two cooler than Sunday given increased
cloud cover associated with front and 850 temps running a touch
cooler as well.

Precipitation will push off to the south and east shortly after
sunset this evening, as drier air filters in behind the frontal
passage. This will allow for decreasing clouds, lower humidity,
and cooler temperatures in the 50s overnight.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Sprawling Canadian high pressure will build down of the Mid
Atlantic from the Great Lakes Tuesday through Wednesday. Gusty
northwest winds on Tuesday will yield much cooler temperatures
in the low to middle 70s area wide, moderating slightly on
Wednesday but still holding in the 70s. The strong and complex
system impacting the southern/central Plains the next couple of
days will lift northward into the upper Midwest late Wednesday
and Wednesday night. This will lift a warm front toward our
region Wednesday night as the high shifts off the coast. This
will likely bring an increase in cloud cover Wednesday night, as
well as increasing shower chances by early Thursday morning,
mainly west of the Blue Ridge.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
An upper level high pressure system will be situated over the
southeastern US through Sunday. There is good agreement that this
upper level high will be in place over SE US but their remains
uncertainty on how far south the high will settle. This means that
their could be the potential for pop up showers and thunderstorms
through Sunday depending on the exact location of the high. These
storms/showers would be kicked off by shortwaves moving through the
system. The presence of this high means that temperatures will trend
upwards through this week with temps potentially hitting the 90
degree mark by this weekend. We will have to continue to monitor how
this setup progresses to determine the potential for any showers and
thunderstorms later this week.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
A cold front will cross the terminals this afternoon and early
evening. Predominate VFR conditions are expected, but scattered
showers and isolated thunderstorms could yield a brief episode
of sub VFR conditions at IAD/DCA/BWI/MTN between 18-21z.
Confidence is low in coverage at this time, so will include
further detail in the TAF as timing/confidence increases.

The front will push to the south and east of the terminals this
evening, with west northwest winds taking hold overnight.
Canadian high pressure will build over the terminals Tuesday
through Wednesday, with gusty northwest winds on Tuesday
slacking and becoming light through Wednesday night. No threat
for precipitation or sub VFR conditions Tuesday and Wednesday.

VFR conditions expected Thursday through Friday but brief
flight restrictions could be possible at terminals if
afternoon showers/thunderstorms form and move through an area.

&&

.MARINE...
A cold front is expected to cross the waters this afternoon and
evening. Gusty southwesterly breezes are expected ahead of the
front, thus an SCA is in effect. A line of showers/storms is
expected with the frontal passage, which could require the need
for Special Marine Warnings in any stronger storm packing gusty
winds.

After a bit of a lull in winds in the wake of the frontal
passage, the gradient is expected to tighten Tuesday morning,
thus SCA conditions expected once again. As high pressure shifts
over the region Tuesday night through Wednesday night, light
winds will prevail with no threat of gusty showers/storms.

High pressure will be in place over the region with light winds
within the mixed layer. This suggests that Small Craft Advisories
aren`t expected at this time for Thursday and Friday.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies remain elevated this morning ahead of an
approaching cold front. Minor flooding is expected at
DC/Annapolis this morning, and monitoring trend the last several
hours, looks possible at Baltimore as well. Have a couple more
hours to mull over the potential of minor flooding at Baltimore
before going with an Advisory. With the frontal passage this
afternoon/evening, anomalies are expected to fall.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Advisory until noon EDT today for DCZ001.
MD...Coastal Flood Advisory until 11 AM EDT this morning for MDZ014.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for
     ANZ531>534-539>541-543.
     Small Craft Advisory from 2 AM to 6 PM EDT Tuesday for
     ANZ530>543.
     Small Craft Advisory from 8 AM this morning to 6 PM EDT this
     evening for ANZ530-535>538-542.

&&

$$
SYNOPSIS...BKF
NEAR TERM...BKF
SHORT TERM...BKF
LONG TERM...JMG
AVIATION...BKF/JMG
MARINE...BKF/JMG
TIDES/COASTAL FLOODING...BKF