Scientific Forecaster Discussion
fxus61 klwx 140804
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
404 am EDT Mon Oct 14 2019
High pressure will build from the Tennessee Valley toward New
England through Tuesday while a secondary cold front approaches from
the Great Lakes and weakens. A strong area of low pressure will move
across the Ohio Valley Wednesday, then re-develop over southeastern
Virginia and move up the coast toward New England Wednesday night
into Thursday. High pressure will follow Friday into the weekend.
Near term /through tonight/...
Main concern early this morning is patchy dense fog. Sfc obs and
nighttime microphysics rgb show dense fog has developed across
parts of the area this morning with vsbys as low as quarter of
an mile in a few spots. Right now, it is patchy and not
widespread enough to issue an advisory, but will continue to
monitor. Otherwise, mostly clear today with high temperatures in
the middle 70s. Clear and cool tonight as high pressure builds
Short term /Tuesday through Wednesday night/...
Tranquil on Tue as high pressure dominates. High moves offshore
Tue night with increasing clouds and showers developing late.
Model guidance has trended slower with onset of precip Tue night
this cycle and have confined pops mainly after 06z Wed. Global
models during the past few days have been trending stronger with
a southern stream low pressure center fcst to move across the
area Wed afternoon showing it to be the more dominant weather
system. As a result, expect some beneficial rains late Tue night
through Wed afternoon with quarter to half inch of rain. Eps
95th percentile shows up to 1.5 inches of rain along the I-95
corridor. Expect a convective line to race through the area Wed
afternoon with frontal passage and gusty northwest behind it. Upslope
rain showers will continue over the Appalachians into Thu
morning in northwest flow.
Long term /Thursday through Sunday/...
In the wake of the aforementioned cold front, a windy day is
expected on Thursday. Sustained winds of 10-15 mph, with gusts up to
25 mph are expected, especially in the late morning/early afternoon.
Additionally, the front will be bringing in the coolest air mass of
the season thus far, with highs in the upper 50s to low 60s. Other
than some upslope showers along/west of the Allegheny Front Thursday
morning, thinking we stay dry and mostly sunny. Overnight lows on
Thursday will be in the upper 30s to low 40s, with some even some
temperatures near freezing at the highest elevations.
High pressure will settle overhead on Friday, resulting in sunny
skies and seasonable temperatures, with highs in the low 60s. Clear
on Friday night with overnight lows into the low 40s. High pressure
will then shift offshore by Saturday, warming temperatures into the
mid to upper 60s. Again, expecting a dry and mostly sunny day.
Overnight lows on Saturday night will be warmer, into the upper 40s
to low 50s, thanks to the southerly return flow. Sunday again looks
dry at this time, with high pressure settled offshore. Temperatures
will be even a little warmer, with highs into the low to mid 70s.
Aviation /08z Monday through Friday/...
Patchy dense fog across the region this morning. Will continue
to monitor. Otherwise, VFR conditions through Tue evening with
potential for MVFR cigs late Tue night and Wed in rain as cold
front crosses the area. Gusty northwest winds behind fropa late Wed
into Wed night.
VFR conditions expected Thursday and Friday behind a cold frontal
passage, with high pressure building into the region. Main concern
will be gusty west-northwesterly winds up to 20 knots or so.
Less windy on Friday, with continued VFR conditions expected.
Winds begin to increase Wed afternoon and smws may be required
with convective line along cold front. Solid Small Craft Advisory conditions
expected Wed night in Post-frontal northwest flow regime.
In the wake of a passing cold front, small craft advisories are
likely going to be needed all day Thursday through much of the day
on Friday. Gale force winds are even a possibility early in the day
on Thursday. Winds will begin to taper off Friday afternoon.
Cf.Y remains in effect for Annapolis as it looks like there is
still a low chance of reaching minor flooding with next high
tide, although my forecast keeps it just below. Will monitor
and cancel early if it doesn't look like it won't reach the
District of Columbia...none.
Maryland...coastal flood advisory until 8 am EDT this morning for mdz014.