Scientific Forecaster Discussion
Area forecast discussion...corrected
National Weather Service Baltimore Maryland/Washington District of Columbia
400 am EDT Sat Jul 4 2015
Synopsis...low pressure will ride along a stationary front over
the area today. The front will push south as a cold front into
North Carolina on Sunday. High pressure will build overhead Sunday
and move off the coast Sunday night. Deeper moisture will return
to the area Monday and Tuesday bringing unsettled conditions.
Near term /until 6 PM this evening/...as of 07z...area of 1010mb mslp
over WV with another over southeastern Virginia. These are along the frontal
boundary that has lifted north as a warm front from NC. This front
will lift north to around District of Columbia today with the low tracking east
across the County Warning Area through the daylight hours. North of this
track/north of the warm front should be stable/no thunder today.
Isolated to scattered thunderstorms are expected along and south
of the boundary.
Overnight activity has been rather light and scattered in coverage
at best. However...activity coming from WV will overspread the area
with most northern sections of the County Warning Area with categorial probability of precipitation for low
quantitative precipitation forecast through middle morning.
Scattered thunderstorms develop this afternoon roughly along and
south of the front which is expected to arc from roughly Cumberland
Maryland to District of Columbia and south. The front shifts south as a cold front this
evening...with precipitation shunted south of most of the County Warning Area by
Bottom line...expect afternoon showers with some embedded
thunderstorms south from the front/low. Maximum temperatures middle to upper 70s
along and north of the front and low 80s south.
Tonight...precipitation clears as do the clouds. Fog develops in typical
Piedmont and valley locations. Min temperatures low to middle 60s...upper 60s
Short term /6 PM this evening through 6 PM Sunday/...brief high pressure.
Sunny with a light/variable flow and maximum temperatures middle 80s.
Long term /Sunday night through Friday/...as high pressure moves off
the coast Sun night moisture and instability begin to return northward
in deep layered srly flow with showers expected to break out Sun
night and continuing through Monday night as a warm front lifts north
through the area. Potential for heavy rains due to high precipitable waters at or above
2.0 inches and since rains will be near an upper level ridge
axis. Localized flash flooding not out of the question.
Drier SW flow establishes over the area late Tuesday and continues
through the end of next week. Lee-side troughs appear the only
mechanism to trigger convection. Otherwise...warmer and humid with
the risk of isolated-scattered diurnally driven convection each day.
Fronts appear to remain well north of the area next week. So
considerably warmer next week than it has been recently.
Aviation /08z Saturday through Wednesday/...weak cold front/low across
the District of Columbia metros today...pushing south this evening. Generally MVFR
conds in likely rain across the terminals with scattered thunderstorms District of Columbia and
south. Patchy fog in typical spots tonight...then VFR Sunday under
IFR ceilings appear likely for kcho late Sun night and early Monday in
rain improving to MVFR Monday afternoon. Low clouds again Monday night
as a warm front lifts through the area with IFR ceilings likely at
kbwi and kmtn.
Marine...Small Craft Advisory for southeasterly flow this morning...shifting northerly this afternoon and
gusting over southern Maryland waters. Small Craft Advisory for southern Maryland waters this afternoon. No
hazards tonight/Sunday under high pressure.
Surface winds expected to be generally light Sun night through Monday night
but strengthen Tuesday-Tuesday night due to channeling srly flow. This
may require Small Craft Advisory.
District of Columbia...coastal Flood Advisory until noon EDT today for dcz001.
Maryland...coastal Flood Advisory until noon EDT today for mdz011-014.
Coastal Flood Advisory until 9 am EDT this morning for mdz017-
Virginia...coastal Flood Advisory until noon EDT today for vaz054.
Marine...Small Craft Advisory until noon EDT today for anz532-540-542.
Small Craft Advisory until 6 PM EDT this evening for anz533-
Small Craft Advisory until noon EDT today for
anz541. Small Craft Advisory until 6 am EDT early this morning