Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Baltimore Maryland/Washington District of Columbia
251 PM EDT Monday may 25 2015
High pressure will remain offshore this week. A southerly flow
will bring warm humid conditions to the middle Atlantic through
Friday. Showers and thunderstorms will be possible each afternoon
and evening beginning Tuesday and lasting through the end of the
Near term /tonight/...
Sunny and dry conditions will continue this afternoon across the middle-
Atlantic. A cumulus field has developed across central Virginia and southern
Maryland. Cumulus will dissipate early this evening and mostly clear and dry
conditions expected tonight.
An upper level ridge will move further off the East Coast tonight.
Middle-high level clouds will move into The Highlands late tonight from
the activity in the Tennessee Valley.
Short term /Tuesday/...
Some dissipating showers may skirt the Allegheny Front into
Tuesday morning. Clouds are expected to move eastward by Tuesday
morning. This will inhibit full heating Tuesday even though 850
temperatures are warmer Tuesday than Monday. The middle-Atlantic will be
under SW flow aloft with the ridge in the Atlantic and multiple
disturbances are expected to ride near or over The Highlands
Tuesday afternoon. The storm motion will be close to 180 so there
wont be much eastward progression. Areas east of the Blue Ridge
should stay dry into Tuesday afternoon. Flow veers to 220 by late
afternoon and scattered showers and thunderstorms may move into the
western suburbs of District of Columbia and Baltimore by sunset. Shear and
instability will be marginal due to the ridge still influencing
the area and cloud cover. Any thunderstorms should stay sub-svr.
Long term /Tuesday night through Sunday/...
Early Summer warmth and moisture will be the main weather words for the
2nd half of the weak. High pressure off the CST and frontal boundary east of the
MS river will keep the east CST in warm humid air. Models are putting out
some likely probability of precipitation. It is hard to want to raise Summer cnvtcn probability of precipitation to
that level several days in advance - for the time being will keep probability of precipitation in
Clouds will be on the increases Tuesday and remain through Thursday. This will keep
insolation down...but moisture/srly flow will also be keeping
nighttime warmth in. Highs will be in the mu80s...lows in the mu60s
xcpt l70s in the cities.
A cold front will stall across the eastern half of the region
Thursday night and Friday...allowing for additional showers and
thunderstorms to develop. Low temperatures Thursday night and
high temperatures Friday could still be 7 to 10 degrees above
The cold front is expected to briefly return northward as a warm
front Friday night before a second cold front...moderately-strong...
approaches the region Saturday. Showers and thunderstorms will
continue to be a threat Friday night and Saturday along the cold
front. Low temperatures Friday night and high temperatures
Saturday could be 10 degrees above normal...reaching the upper 60s
and near 90...respectively.
The cold front should slowly push through the region Saturday
night into Sunday. The European model is slower than the GFS
in doing this. Nonetheless...the chance for showers and
thunderstorms will linger throughout the period. Lows Saturday
night and highs Sunday will still be above average.
A wedge of high pressure will build southward along the East
Coast...helping to cool conditions down a little. However...
overrunning moisture from the south and passing middle-level
disturbances to the north could bring another threat for rain
showers. Thunderstorms should be limited. Temperatures may be a
few degrees above normal each period.
Aviation /18z Monday through Saturday/...
VFR conditions expected today and tonight. -Shra/thunderstorms in the vicinity possible
Tuesday afternoon mainly across mrb/cho.
VFR majority of the time Tuesday ngt-Thu. Rain shower/thunderstorm will be possible...
especially in the afternoon/Erly evening. Srly winds will gust into the l20s
during the afternoon.
MVFR or IFR conditions possible at all terminals Thursday night
and Friday with showers and thunderstorms. Winds generally southwest
5 to 10 knots with a few higher gusts.
S winds will persist across the waters today through Thursday.
Mixing during the afternoon will lead to Small Craft Advisory conditions across all
the waters. Winds should subside tonight across the upper tidal
Potomac and Chesapeake Bay north of Pooles Island. This trend will
continue Tuesday and Tuesday night.
Srly flow will continue over the waters Tuesday ngt-Thu. Small Craft Advisory in effect Tuesday
night for the lower ptmc/main portion of the Bay. This will likely need to be
extend into Wednesday. Rain shower/thunderstorm will be possible as well.
No marine hazards expected Thursday night through Friday.
District of Columbia...none.
Marine...Small Craft Advisory until 6 PM EDT Tuesday for anz531-538-539.
Small Craft Advisory until 6 am EDT Wednesday for anz532>534-
Small Craft Advisory until 10 PM EDT this evening for anz530-
Small Craft Advisory from 11 am to 6 PM EDT Tuesday for anz530-