Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
959 am EDT sun Aug 2 2015
high pressure will dominate the area through tonight. A cold
front will approach the area Monday before stalling out overhead
Monday night into Tuesday. The boundary will remain nearby through
the end of the week while a wave of low pressure rides along
it...bringing unsettled conditions especially during the latter
half of the week.
Near term /through tonight/...
high pressure will dominate the weather pattern today.
However...a pesky inversion has trapped some middle-level moisture
over much of the area...resulting in a middle-level cloud deck. Some
guidance clears this out during the afternoon...while others keep
the clouds around much of the day. Increased sky cover for this
morning and much of the afternoon as a result. West-southwest flow
will help temperatures rise into the 80s in most
locations...except low 90s in the immediate Washington
District of Columbia/Baltimore metropolitan. It should be noted that if clouds are
persistent enough...highs may end up a bit lower than expected.
Overnight lows will dip back into the upper 50s to middle 60s
west of the Blue Ridge to the upper 60s to lower 70s east of the
Blue Ridge...slightly milder over the metropolitan centers. Some patchy
fog is possible overnight inland and away from the metropolitan.
Short term /Monday through Tuesday night/...
upper trough and cold front will approach from the west Monday.
Ahead of the front...south to southwest flow will increase and
temperatures will become hot. Afternoon readings will likely reach
the 90s in most areas. However...low dew points should keep US
from reaching head advisory levels...with most dew points staying
well within the 60s. Chances for showers and thunderstorms will
increase from west to east very late in the day.
A weak cold front will move into the region Monday night and it
is expected to stall out overhead for Tuesday and Tuesday night. A
couple showers and thunderstorms may impact the area Monday
night...especially across northern Maryland and the Potomac
Highlands where forcing may be a bit stronger along the boundary.
Min temperatures Monday night will range from the 50s/60s in the Potomac
Highlands to the middle and upper 70s in downtown Washington and
Baltimore. If some clearing occurs late...patchy fog will once
again be a concern inland and away from the metropolitan.
The stalled boundary over the area will be weak Tuesday and
Tuesday night. Therefore...little temperature gradient is expected
along the boundary. There will be a dewpoint gradient and with
higher dewpoints south of the boundary a couple showers and
thunderstorms may pop up Tuesday afternoon and evening...mainly
across central Virginia into southern Maryland. Even across these
areas convection is expected to remain isolated/scattered since
the boundary will be weak. Any convection should dissipate
overnight Tuesday with the loss of daytime heating.
Long term /Wednesday through Saturday/...
the boundary will remain nearby Wednesday through Saturday. A
zonal flow aloft will separate upper-level low pressure over
Canada from an upper-level ridge over the south-central Continental U.S.
Into the Atlantic Ocean. A series of disturbances will rotate
through the area in the zonal flow aloft. These disturbances will
interact with the frontal boundary...increasing the chance for
showers and thunderstorms. Timing of these are uncertain this far
out...but guidance indicates that the best chance for convection
may be Wednesday night and Thursday...and possibly again later
Friday into Saturday. Again...timing this far out is highly
Aviation /14z Sunday through Thursday/...
VFR to persist today into Monday...with just slight chance of
reduced ceilings/visible in patchy fog at mrb/cho. Winds will increase
out of the south to southwest on Monday. Wind speeds in the
10-15kt range will be possible. Scattered showers and
thunderstorms may develop Monday evening and persist into the
A weak cold front will stall over the area Monday night and it
will remain nearby through Thursday. A shower or thunderstorm is
possible Monday night and Tuesday...but most of the time will be
dry. There is a better chance for showers and thunderstorms along
with reduced ceilings/visibilities Wednesday night and Thursday.
winds will remain below Small Craft Advisory today into tonight but will increase
with southerly channeling on Monday. Small craft conditions are
now expected...and Small Craft Advisory has been issued.
A cold front will stall out near the waters Monday night and it
will remain nearby through the end of the week. A Small Craft
Advisory may be needed for portions of the waters Tuesday. A
series of disturbances will ride along the boundary...increasing
the chances for showers and thunderstorms during the latter
portion of the week.
astronomical tides are higher due to the nearly-full moon...but
anomalies are low enough that tidal flooding will not be a threat
through today. Southerly flow ahead of the next front will
elevate tidal anomalies on Monday...but at this point not
expecting minor flooding. This possibility will require monitoring
District of Columbia...none.
Marine...Small Craft Advisory from noon Monday to 6 am EDT Tuesday for
Small Craft Advisory from 3 PM Monday to midnight EDT Monday
night for anz535-536.