-- Discussion containing changed information from previous version are highlighted. --
581
FXUS61 KLWX 140128
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
928 PM EDT Thu Jun 13 2024

.SYNOPSIS...
High pressure moves further offshore today. A cold front tracks into
the region Friday, with increasing shower and thunderstorm chances.
Secondary high pressure builds back in for the weekend with lower
humidity and slightly cooler temperatures. Hot and humid conditions
return next week as a strong upper ridge impacts the area.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Current radar imagery shows a couple showers extending from
northern Loudoun County northeastward across north-central
Maryland, with dry conditions elsewhere. These showers may
continue for another hour or two as they slowly drift off toward
the east-northeast, but should struggle to intensify given the
stout mid- level inversion and ample mid- upper level dry air
present on the 00z IAD sounding. After these showers dissipate,
skies are expected to clear out for much of the night. A few
remnant mid- high clouds associated with decaying convection
that is currently ongoing over the Ohio Valley may approach
western MD and the WV Panhandle just prior to daybreak. Some
patchy fog may be possible late tonight, and overnight lows are
forecast to be in the 60s for most (around 70 in downtown DC
and Baltimore).
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
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Friday morning, conditions should be mostly dry with clouds
increasing from the northwest as a result of an approaching cold
front moving in from the Great Lakes region. Another above
normal temperature day is expected, with highs in the low 90s
across the lower elevations and mid to upper 70s for the
mountains. The cold front will likely become more negatively
tilted as it approaches areas along and east of the Blue Ridge
which may enhance coverage and intensity of any showers and
thunderstorms that spawn. For now, expecting isolated to
scattered thunderstorms to develop Friday afternoon and evening
just ahead of the frontal passage. With increased CAPE, slightly
steep low-level lapse rates, and increased flow aloft, a few of
theses storms may become strong to severe. The area of best
chances for this looks to be across north-central to northeast
MD. The main hazards for these storms will likely be damaging
winds, with increasing DCAPE through the afternoon. Cannot rule
out some hail with these storms as well. Most convection likely
moves east of the area after midnight Friday. Overnight lows
will fall into the low to mid 50s across the mountains and
slightly warmer into the low to mid 60s further east across the
lower elevations.

Secondary high pressure will build in for the weekend, with
decreasing humidity and slightly cooler temperatures. Highs will
generally be in the low to mid 80s both days, with winds remaining
light. Overnight lows Saturday night will be in the 50s for most
areas, with gradual humidity increase Sunday night with lows in the
low 60s for most areas.
-- End Changed Discussion --

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Upper level ridging sets up over the eastern half of
CONUS for the entirety of the long term period. Sunday will be the
coolest day of the long term period with high temperatures in the
80s for most. Those at higher elevations will stay in the mid to
upper 70s. With high pressure at the surface, dry conditions are
expected areawide. Dry conditions are expected overnight Sunday into
Monday with low temperatures 60s for most.

As we head into the workweek and the ridge settles overhead, above
average temperatures will be the main story. While there is a bit of
model discrepancy on exact high temperature forecasts, models agree
on above average temperatures each day. High temperatures each day
will be in the 90s with only those at highest elevations staying in
the 80s. With dew points in the upper 60s, heat indices will rise
into the upper 90s to even exceeding low 100s possible. Overnight
low temperatures will cool into the 60s to low 70s each night with
the metro areas staying in the upper 70s.

&&

.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
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VFR conditions are expected through early Friday, along with
light southerly winds. A few showers are evident on radar this
evening, but this activity is expected to remain off to the
north and west of the terminals. Some patchy fog is possible
later tonight and into early Friday but visibility restriction
at the terminals are not expected at this time.

By Friday afternoon, a cold front will approach the area and
bring the potential for isolated to scattered thunderstorms.
Some of these storms could become severe, especially for the
more northeastern terminals. Sub-VFR conditions may be briefly
possible Friday afternoon and evening with any of these showers
and storms that approach the terminals.

VFR conditions return for the weekend with light winds as a result
of reinforcing high pressure nearby.

VFR conditions are expected throughout the long term period with
high pressure and upper level ridging overhead. Southeasterly winds
on Sunday will shift to southerly on Monday. Dry weather is expected
both days with winds remaining light, blowing 5-10 knots.
-- End Changed Discussion --

&&

.MARINE...
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SCA conditions will continue in southerly flow over the Bay and
Lower Tidal Potomac through much of the night. Prevailing sub-
SCA southerly flow is expected over the waters on Friday, but
SMWs may be needed for any strong to severe thunderstorms that
cross the waters during the late afternoon or evening hours.
High pressure returns for the weekend. Cannot rule out SCA
conditions early Saturday with northerly channeling building for
the open waters especially.

Southeasterly winds on Sunday are expected to remain below SCA
criteria. By Monday morning, winds shift to southerly and will
primarily stay below SCA criteria. Winds in the lower portions of
the waters will near SCA criteria  Monday evening, gusting up to 17
knots with a SCA being possible during this time.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
Current tidal anomalies remain slightly elevated, generally ranging
between 0.5 to 0.7 feet. At this point, only the sensitive locations
like Annapolis and Straits Point are expected to reach Action stage
during the next several high tides. Water levels do quickly drop off
over the weekend behind a cold front. North to northwesterly flow
should push a lot of the excess water back toward the south.

&&

.CLIMATE...
High temperatures early next week. Below is a list of record high
temperatures for June 17th, 18th, and 19th, the year the record
was set, and the current forecast high temperatures for those
days. Daily temperature records are currently only maintained at
DCA, IAD, BWI, and MRB. Others are shown for reference.

                                     Monday Jun 17th
Climate Site                  Record High     Forecast High
Washington-National (DCA)     99F (2022)          93F
Washington-Dulles (IAD)       96F (2022)          94F
Baltimore (BWI)               96F (2022+)         92F
Martinsburg (MRB)             98F (1939+)         91F
Charlottesville (CHO)         97F (2022)          93F
Annapolis (NAK)               96F (1939)          87F
Hagerstown (HGR)              96F (1952)          92F

                                     Tuesday Jun 18th
Climate Site                  Record High     Forecast High
Washington-National (DCA)     97F (1944)          95F
Washington-Dulles (IAD)       94F (2018+)         95F
Baltimore (BWI)               97F (1957+)         93F
Martinsburg (MRB)             99F (1943)          92F
Charlottesville (CHO)         96F (2014+)         93F
Annapolis (NAK)               96F (1957)          89F
Hagerstown (HGR)              95F (1957)          93F

                                    Wednesday Jun 19th
Climate Site                  Record High     Forecast High
Washington-National (DCA)     99F (1994)          95F
Washington-Dulles (IAD)       98F (1994)          95F
Baltimore (BWI)               99F (1994)          93F
Martinsburg (MRB)             96F (1994+)         92F
Charlottesville (CHO)         97F (2018)          94F
Annapolis (NAK)               96F (1993)          89F
Hagerstown (HGR)              97F (1994)          94F

+ indicates that value has been reached on multiple years, with
the year displayed being the most recent.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 5 AM EDT Friday for ANZ530>534-
     537>543.

&&

$$

SYNOPSIS...ADM
NEAR TERM...KJP/ADM
SHORT TERM...ADM
LONG TERM...AVS
AVIATION...AVS/ADM
MARINE...AVS/ADM
TIDES/COASTAL FLOODING...LWX
CLIMATE...BRO