FXUS61 KLWX 090145
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
945 PM EDT Wed Jul 8 2020
High pressure will remain offshore through tonight while low
pressure develops near the Carolina Coast. The low will slowly
move up the Mid-Atlantic Coast Thursday and Friday before moving
off to the northeast Friday night. The low may develop tropical
characteristics during this time so this will have to be
monitored. An upper-level trough will build overhead Saturday
while a cold front passes through the area. The upper- level
trough will hang around for early next week.
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A few showers and thunderstorms remain over western Maryland
and eastern West Virginia, while the rest of our CWA remains
dry with subsidence aloft. Low pressure located off of the
Carolina Coast is being monitored closely for potential tropical
development. Please see the National Hurricane Center website
for additional information.
A few showers may approach southern MD and the VA Piedmont
late tonight as the low to the south begins to edge northward,
however chance is low. Areas of low clouds and fog are expected
again as moisture gets trapped underneath the subsidence and
nocturnal inversions. Humid conditions will persist for tonight
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
The low will slowly move north up the Mid-Atlantic Coast
Thursday through Friday before moving off to the northeast
Friday night. There is still some uncertainty as to the exact
track, but it is increasingly likely that it will be closer to
the coast or even a little offshore. This system does have a
chance to interact with the warmer waters off the coast to
develop tropical characteristics, so it will have to be
monitored closely. As of now, it appears that the most likely
track will keep the heaviest rain off to our east.
For Thursday, an easterly flow will develop around the low that
is to the south and this will allow for more humid conditions.
The best chance for showers and a thunderstorm will be
southeast of Interstate 95 across southern Maryland where
moisture will be a bit deeper closer to the low. Elsewhere, much
of the time may actually be dry since there will be little
convergence and subsidence will still play a role as upper-level
high pressure remains nearby just to the north and northeast.
Did allow for the possibility of a shower/thunderstorm. Areas
near and southeast of Interstate 95 will not be quite as hot as
recent days due to more cloud cover, but it will be quite humid
with dewpoints in the 70s.
More humid conditions Thursday night. Most of the time may turn
out dry northwest of Interstate 95 as any convection that does
develop diminishes with the loss of daytime heating. Some
showers are possible, especially southeast of Interstate 95.
The best chance for showers and perhaps a thunderstorm will be
Friday into Friday evening as the low passes by to our east. As
of now, the best chance for precipitation will be east of the
Blue Ridge Mountains. The most likely track would keep the
heaviest rain to our east, but this will have to be monitored
because a slight adjustment westward means that heavier rain
could approach our eastern areas and even toward I-95.
Weak subsidence may return late Friday night as the low moves
away from the area. Areas of fog are possible as well with winds
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A cold front will approach and move through our region Saturday and
into Sunday. Ahead of this front, winds will be out of the south
leading to advection of warm and moist air into our region on
Saturday. This will lead to increased instability ahead of the
approaching front. The front will act as a lifting mechanism leading
to the potential for the formation of strong thunderstorms ahead of
the frontal passage. Saturday looks like the best chance for
thunderstorms but there remains some uncertainty on the exact timing
of the frontal passage. If the front passage timing is slower then
thunderstorm threat could be limited or even pushed to Sunday. The
front looks to be through our area by late Sunday morning but the
upper level trough will be overhead Sunday which could lead to some
scattered showers through Sunday afternoon. Temperatures will trend
upwards into the 90s during the day with overnight lows in the
High pressure builds back over our region Monday through Tuesday but
there are hints of a stalled boundary to our southeast. If this
boundary stalls further north closer to our area, some showers could
linger through the early parts of next week. Near 90 degree weather
looks to continue through the early parts of next week.
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
VFR conditions are expected through this evening. More low
clouds and fog are possible late tonight into Thursday morning.
Low pressure will approach Thursday into Friday before passing
by to our east Friday into Friday evening. Showers and a
thunderstorms are possible, especially Friday when the low will
be closest. Restrictions are possible mainly over BWI and MTN,
maybe DCA. Also, low clouds and subVFR cigs are possible
Thursday night into Friday due to an easterly flow.
A front will bring scattered thunderstorms, possibly bringing
restrictions over the terminals, on Saturday which could lead to
periods of subVFR conditions and along with gusty winds. VFR
conditions will likely return late Sunday and into Monday.
A southeast flow this afternoon will turn east and northeast
tonight into Thursday as low pressure develops to the south and
begins to edge northward. The low will pass by to our east Friday
into Friday evening before moving away from the waters Friday
night. A Small Craft Advisory is in effect over the water due to
this approaching system through Thursday night. However, Gale
Force winds are possible overnight Thursday into Friday but not
confident enough to issue it at this moment. Will continue to
monitor and update the hazard if needed. Any gusty winds should
weaken Friday night as the low moves away.
A front will pass over the waters Saturday and into Sunday. Some
gusty winds over 18 knots will be possible with storms.
Southerly to easterly flow tonight and into tomorrow could
bring water levels up enough to pose coastal flooding in the
northern Bay waters late tonight and Thursday morning, and in
the central Bay waters later in the day Thursday.
MARINE...Small Craft Advisory from 6 AM to 8 AM EDT Friday for ANZ530-
Small Craft Advisory from 5 PM Thursday to 8 AM EDT Friday for
Small Craft Advisory from noon Thursday to 8 AM EDT Friday for
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