Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
329 am EDT Tuesday Jul 29 2014
High pressure will build overhead through midweek...bringing
pleasant weather. An upper level trough of low pressure may develop
east of the Mississippi River at week's end.
Near term /today/...
High pressure building into the middle Atlantic overnight. At 2 am amazingly
pleasant outside for Jul 29 - clear skies...temperatures in m60s...dewpoints in m50s.
Upper low will persist over Ontario today as surface high pressure
moves into the middle Atlantic region. Nearly winds will bring extremely plsnt
weather to the mid-Atlantic. Forecast maximum temperatures in the middle to upper 70s are
What a difference 3 yrs makes: 7/29/11 high temperatures - dca 104..iad
103..BWI 101...all records for this date.
Short term /tonight through Wednesday night/...
Upper level trough will continue to spin while the desert SW bakes under the
upper ridge. Forecast min temperatures tonight range from the upper 40s to low
50s in the mountains to the upper 50s near Interstate 95.
High pressure persists across the area Wednesday. Isolated thunderstorm are possible across
the Potomac Highlands Wednesday afternoon as a disturbance moves around the
upper level low. High temperatures will remain below normal...barely reaching
Wednesday night continues to be very comfortable west/ lows in the 50s west of
I-95...mu60s in the cities and along the Bay.
Long term /Thursday through Monday/...
Hipres will remain in the western Atlantic through the extend period...supporting
southerly return flow across the County warning forecast area. Another key player in the weather pttn
for the upcoming period will be the deep upper low...which will remain north of
the Great Lakes through the weak...evolving into a sharply amplified trough
axis for the weekend. Thus...will be transitioning from a period of cool/dry
weather to a period where daily probability of precipitation need to be considered.
Will keep Thursday dry due to westerly flow aloft...then upglide/thte/mstr
advection become too much to ignore. Suspect we/ll have some positive vorticity advection too by
the weekend...but thats too fickle to time this far out. Instability remains
modest...but should be sufficient to support mainly diurnal thunder.
Will keep rain showers for the nighttime hours.
Normal highs for Ely Aug upper 80s...W/ lows around 70f in the urban
downtowns and in the 60s outlying areas. Temperature forecasts throughout this period
below normal. Thursday may be the warmest day due to insolation and lack of
precipitation...but even then maxt middle 80s west/ dewpoints in the 50s.
Aviation /07z Tuesday through Saturday/...
VFR expected today. Patchy fog may impact cho-mrb early Wednesday
Thursday...VFR under hipres.
Friday and Sat...mainly VFR though may have local flgt restrictions in scattered
Winds are now waning on the waters. Still some gusts in the upper
teens on the widest part of the Maryland part of the ches Bay as well as
lower tidal ptmc so will likely let the Small Craft Advisory remain in effect until its
planned expiration at 6 am. High pressure will move into the
region today. Nearly winds 5-10 kts expeceted today and Wednesday on the waters.
Hipres offshore will provide gnly light winds to the waters. Southerly flow Thursday
will start to back Ely for Fri-Sat. Prognosticated sustained spds at or below 10 knots.
No headlines anticipated through Sat.
District of Columbia...none.
Marine...Small Craft Advisory until 6 am EDT early this morning for