Scientific Forecaster Discussion
fxus61 klwx 191923
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
223 PM EST Fri Jan 19 2018
high pressure to the south will dominate the weather through
the weekend. A cold front will approach the region Monday before
passing through Monday night into Tuesday. High pressure will return
for Wednesday through Thursday of next week before moving offshore
Near term /through tonight/...
high pressure extends from the southeastern Continental U.S. To the mid
Atlantic. Wave clouds still reside across southern Pennsylvania
into western maryland; otherwise the forecast area is mostly
sunny aside from a few cirrus.
Winds never fully decoupled last night. Tonight's setup will be
quite similar aside from a lack of an offshore coastal cyclone.
Nonetheless, in light of good model agreement, am hesitant to
undercut low temperatures. Will therefore leave lows in the
upper 20s to near 30.
Short term /Saturday through Sunday night/...
while the high pressure ridge remains in place through the
weekend, there will be a couple of transitory features in the
mean westerly flow: southern stream 500 mb shortwave/cyclone
along the Gulf Coast, and northern stream low pressure across
southern Canada with weak attendant boundary emanating
west/southwest from it.
While neither will have a direct impact locally, warm advection
in the wake of the former disturbance will spread moisture
north Saturday-Saturday night. Saturday will still be sunny. At
this time, it appears as though any precip will be confined to
mountains Saturday night. Further, it is looking more likely
that temperatures will remain above freezing through this time,
so have removed mention of freezing rain.
Sunday will be cloudier, in part due to the pressure weakness.
But forcing will be too meager for anything but clouds.
Thermally, the cloud cover likely will lead to slightly cooler
temperatures, but highs will still be at-or-above 50 degrees.
Long term /Monday through Friday/...
a cold front will approach from the west Monday before passing
through Monday night into Tuesday. Showers are expected ahead of the
boundary...especially Monday night into Tuesday. A southerly flow
ahead of the boundary will allow for mild conditions Monday...but
low clouds and fog are possible and if this develops it would cause
temps to be a bit cooler than currently forecasted.
The cold front will move off to the east later Tuesday and high
pressure will return for Wednesday and Thursday. Dry and seasonably
chilly conditions are expected during this time.
The high will move offshore late in the week and milder conditions
will return due to a southerly flow.
Aviation /19z Friday through Wednesday/...
VFR conditions will prevail through the weekend with high
pressure positioned just southwest of the terminals.
A cold front will approach from the west Monday. Low clouds and fog
are possible ahead of the cold front due to warm and moist air
overrunning cooler air near the surface...but confidence is low at
The cold front will pass through Monday night into Tuesday...
bringing showers and subvfr conditions. High pressure will return
for later Tuesday and Wednesday with VFR conditions likely.
winds will be 10 kt or less through the weekend with high
pressure positioned southwest of the waters. Flow will have a
primary southwest component, but will veer west/northwest by
Sunday as a front approaches.
A cold front will approach the waters Monday before passing through
Monday night or Tuesday. High pressure will return for the middle
portion of next week. A Small Craft Advisory may be needed for
portions of the waters Monday night through Wednesday.
District of Columbia...none.