Scientific Forecaster Discussion
fxus61 klwx 171837
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
237 PM EDT Thu Oct 17 2019
A low pressure system over the northeastern US will continue to
track further northward away from our region. High pressure will
build into our region through Saturday afternoon. Precipitation will
be possible Sunday as a tropical low moves south of region and again
midway through next week due to a potential cold front.
Near term /through tonight/...
A strong surface low over the northeastern US will continue to shift
northeastward over eastern Canada. As this low moves further away
from our region, the pressure gradient will slowly weaken through
this evening. The strong winds we have been experiencing throughout
the day will continue to weakened with gusts dropping below 30s knots
by this evening. Winds will remain elevated over our coastal waters
through this evening which has led US to keep the Gale Warning in
place until 6pm but it may need to be extended. A general westerly
flow has lead to upslope induced clouds over our region. Skies are
expected to slowly clear through the overnight periods as the
westerly flow weakened and drier air is transported into our area.
Some upslope induced showers can't be ruled out for the peaks in our
eastern West Virginia zones and western Maryland. Temperatures this
evening will be cooler with temperatures hovering in the 40s east of
the Blue Ridge and the 30s to low 40 west of the Blue Ridge. Higher
elevations have the potential to experience lows in the upper 20s to
Short term /Friday through Saturday night/...
High pressure will shift over our region from the Midwest on Friday.
No precipitation expected for Friday as winds weakened and become
more northwesterly. This will lead to advection of cooler and drier
air into our zones. Some lingering gusty winds will be possible
during the day over our land areas due to weakening pressure
gradient but I expect no gusts over 25 knots. The gusty winds have
led US to replace the Gale Warning ending at 6pm today with a Small
Craft Advisory issued through Friday afternoon. Friday evening is
expected to be the coolest evening yet with most of our region west
of the I-95 corridor experiencing lows in the 30s with a few higher
elevation points dropping down to near freezing. Temperatures Friday
evening will be close to frost advisory criteria but there remains
some uncertainty and that falls in my period 4 and will leave for
High pressure will be in place over our region on Saturday but will
quickly shift out our region Saturday afternoon. A potential
tropical system forming in the Gulf is forecast to shift
northward through the southeast US and move northward toward the
southern parts our forecast area. Dry conditions expected
Saturday but a weak return flow is forecast to form ahead of the
coastal low. This will lead weak advection of warm and moist
air into our region. The earliest that precipitation from the
tropical system could start to affect our region will be
Saturday evening in central Virginia. The exact track of this
system remains uncertain but the low is expected to move quickly
through our forecast area Saturday evening into Sunday. At this
time I have only included chance pops for our counties in
central Virginia during the late Saturday to early Sunday
Long term /Sunday through Wednesday/...
Potential tropical cyclone 16 is expected to move rapidly
northeastward during the next couple of days and pass south of the
area Sunday as an extratropical/Post-tropical cyclone. Some light
rain will be possible Sat night into Sunday morning on the north and
left side of the storm track. Not looking at a lot of precip with
this system as it will be fast mover and will be far removed from
the storm track. Mid- upper level ridge builds during the early part
of next week with another storm system likely impacting the area
during the middle portion of next week.
Aviation /18z Thursday through Tuesday/...
Thursday through Saturday, the strong winds that have been
occurring today will continue to weakened through this evening.
Cloud cover will start to break this evening as the strong
westerly flow starts to weakened. Winds will remain out of the
west but will slowly become northwesterly by Friday. Skies are
expected to be mostly clear Friday and Saturday but some rain
may move into the cho terminal by Saturday evening. VFR
conditions expected through Saturday afternoon.
MVFR cigs in rain possible Sat overnight into sun.
A strong pressure gradient will lead to strong gusty winds over the
waters today through Friday. Gale warnings are in place for all of
our waters until 6pm but may need to be extended if winds over 34
knots linger. Small craft advisories are in place from 6 PM this
evening until 6pm on Friday. These small craft advisories may need
to be extended through Friday evening but winds will be marginal
near 18 knots. No small craft advisories expected at this time for
Small Craft Advisory conditions likely Sunday into Monday.
District of Columbia...none.
Marine...Small Craft Advisory from 6 PM this evening to 6 PM EDT Friday
Gale Warning until 6 PM EDT this evening for anz530>543.