Area Forecast Discussion
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FXUS61 KLWX 301459
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1059 AM EDT Fri Sep 30 2016
Upper level low pressure over Kentucky will begin to lift
northward towards the Great Lakes today and into the weekend. The
low will pass by to the north early next week as it moves
offshore. High pressure will build into the area late in the
weekend and into early next week.
.NEAR TERM /THROUGH TONIGHT/...
Our forecast area seems to be dodging the bullet this time. Rain
continues to our east and west. Deep cloud cover continues as
upper low spins over KY. For the afternoon rain chances will
continue but not expecting any flooding. Highs only expected to be
in the mid to upper 60s.
Overcast skies...rain chances continue tonight. Little diurnal
variation in temperature - lows in the low to mid 60s east of the
mountains, mid to upper 50s west.
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Upper-level low will continue to track northward towards the Great
Lakes and then pass by to our north as it moves eastward toward the
weakening ridge over the Atlantic Saturday into Sunday. Impacts
associated with the low will begin to lessen Saturday...with only a
few spotty showers lingering (mainly across the northern half of the
CWA). By 00Z Sunday...dry slot expected to have finally worked its
way through the area...as frontal boundary pushes off to the east.
This will finally eliminate precipitation chances into Sunday...for
all but upslope areas along the western slopes. Drying out Sunday
with highs in the M/U70s.
.LONG TERM /MONDAY THROUGH THURSDAY/...
Surface high pressure remains over New England through mid-
week...with mostly dry and seasonable conditions across the Mid-
Atlantic. Highs in the 70s early next week...though, as onshore flow
develops around the surface high by mid-week...high temperatures
will fall into the 60s.
Hurricane Matthew is located along the north coast of South
America. It is expected to cross Cuba Monday. It is far too early
to discuss possible impacts to Mid-Atlantic region.
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
Upper level low will continue to impact the area through Friday with
onshore flow causing low ceilings at most terminals. Periodic
drizzle/showers through tonight...with IFR conditions prevailing.
Though, brief LIFR ceilings are possible in the heaviest showers.
Improving conditions Saturday as upper-low begins to lose its
influence over the area. Prevailing VFR conditions Saturday through
early next week as high pressure builds into the area.
Winds have diminished from the previous two days but SCA remains
in effect for all waters. Extended the SCA headline for the
Chesapeake Bay into early Saturday morning...as guidance indicates
SCA gusts lingering awhile longer there. Gradient relaxes for all
locations by early Saturday...with winds remaining below SCA
criteria into early next week as high pressure builds into the
Water levels running 1.5 to 2 feet above astronomical predictions
early this morning. With the continued east wind, do not expect
much change. Moderate flooding still expected at St. George
Island and Annapolis.
Confidence is sufficient to extend most Advisories and Warnings for
both tide cycles on Saturday. The exception: Southern Baltimore,
where the tide cycle occurs Saturday evening (will only go through
Saturday day). Skill, water level forecasting isn`t great beyond
36 hours. Consequently, have a Coastal Flood watch for Saturday
evening in St. Marys and Anne Arundel Counties, where moderate is
still forecast, but will less confidence.
On the upper tidal Potomac, at least minor tidal flooding should
occur through at least Saturday evening.
A gradual decline in water levels should transpire Saturday night
and Sunday. It is unclear at this time whether an additional tide
cycle would be affected. There is plenty of time to figure that out.
DC...Coastal Flood Warning until midnight EDT tonight for DCZ001.
MD...Coastal Flood Advisory until midnight EDT tonight for MDZ013.
Coastal Flood Warning until noon EDT Saturday for MDZ014-017.
Coastal Flood Watch from Saturday afternoon through Saturday
evening for MDZ014-017.
Coastal Flood Advisory until 8 PM EDT Saturday for MDZ016-018.
Coastal Flood Advisory until 2 PM EDT Saturday for MDZ011.
VA...Coastal Flood Advisory until midnight EDT tonight for
Coastal Flood Advisory until 8 PM EDT Saturday for VAZ057.
MARINE...Small Craft Advisory until 2 AM EDT Saturday for ANZ530>534-
Small Craft Advisory until 7 PM EDT this evening for