Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
1107 am EDT Tuesday Oct 6 2015
low pressure off the southeast coast will move offshore. High
pressure will build into the middle Atlantic region today through
Thursday. A cold front will cross the area Friday. High pressure is
expected to return to the area for the weekend.
Near term /until 6 PM this evening/...
today...sunny with a slight north breeze...maximum temperatures generally
low to middle 70s.
Short term /6 PM this evening through 6 PM Wednesday/...
tonight...milder with increased moisture. High clouds build in
ahead of a shortwave. Min temperatures generally middle to upper 50s. Will
need to look more into timing of clouds for fog potential.
Wednesday...weak shortwave crosses the area from the west. Sref/GFS
support low chance probability of precipitation...so introduced 20/30 probability of precipitation for the southwestern
zones in the afternoon.
Long term /Wednesday night through Monday/...
high pressure builds back into the area Wednesday night aftr a weak cold fnt
moves through. Lows in the mu40s west of I-81...50s eastern half of the forecast
area. Thursday west/ the high over the region expect a M sunny day west/ highs in
the m70s over much of the region.
A cold fnt will be aprchg the east CST Friday. Timing will be key to the high
temperature forecast - if it does not arrive until Friday evening temperatures may get into
the u70s. For now will hold in the m70s...especially if rain shower do move
in during the afternoon. There is a bit of skinny cape in the sndg
profiles Friday afternoon...but for time being will leaving thunder mention out
Rain shower chance should be ongoing Friday evening. Lows in the lower 50s. Models
diverge on Sat solution - GFS moves the fnt far away west/ the high building
in rapidly while the Euro is slower west/ the exit. Regardless temperatures
will be about 10 degrees cooler Sat than Friday.
High pressure over the area Sunday. Much of the area looks to drop
into the 40s Sat night. High Sunday in the m60s.
Aviation /15z Tuesday through Saturday/...
VFR today. Calm again tonight with more fog possible though this
may be limited as high clouds overspread the area. Low chances for
showers in vicinity of kcho Wednesday afternoon from a weak upper
Majority of extend will see VFR conds. Primary xctpns could be if
overnight fog develops at cho/mrb/iad...and west/ an aprchg cold fnt Friday
which could trigger rain shower/isolated thunderstorm and lowered ceilings Friday aftn/eve.
cancelled Small Craft Advisory as winds have subsided.
Main concern in the extend portion of the forecast will be an aprchg cold
fnt late Friday - srly winds could reach Small Craft Advisory values Friday aftn/eve...
then again Sat on nwrly flow behind the fnt.
St. George's creek came within a few hundredths of a foot of
moderate flood during this morning's high tide cycle...but has
since started coming back down. Coastal Flood Warning for St.
Mary's expired at 11 am and coastal flood adivsory for minor
flooding continues until 7 am Wednesday.
Northeasterly flow has weakened with minor coastal flooding for upper
tidal Potomac and Anne Arundel/Calvert/St Marys high tide through
Wednesday morning. Current coastal Flood Advisory continues
through tonight and will need to be extended for probably all
zones. More Baltimore minor flooding likely high tide tonight.
Departures continue to slowly decrease in light northerly flow through
District of Columbia...coastal Flood Advisory until 7 am EDT Wednesday for dcz001.
Maryland...coastal Flood Advisory until 7 am EDT Wednesday for mdz014-017-
Virginia...coastal Flood Advisory until 7 am EDT Wednesday for vaz054.