Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 161430
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
930 AM EST Thu Feb 16 2017

.SYNOPSIS...
High pressure builds overhead through Friday. A weak cold front will
move through early Sunday. High pressure returns Sunday into early
next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Gusty northwest flow across the area this morning will persist
into the afternoon. Scattered flurries and snow showers have
developed and continue to move across the region from about the
DC metro on northward. Brief reductions in visibility and a
quick dusting to locally up to a half inch of snowfall
accumulation are possible, especially the closer you go to the
Mason-Dixon line. Latest hi-res model runs and NAM12 snow-
squall parameter depict snow shower coverage decreasing across
much of the region later today, except northeast Maryland as
lobe of vorticity rotates through, where scattered flurries
likely to continue. Otherwise, partly- mostly cloudy skies with
gusts up to about 30 mph. Highs in the 30s to low 40s.

Strong radiational cooling tonight under clear skies and weakening
wind speeds will allow low temperatures to fall into the 20s across
the entire area.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
High pressure slides to the south Friday...keeping westerly wind
component through much of the day. This will help temper warming
somewhat. Though, gradual airmass modification will bring
temperatures back near climatological norms. It will certainly feel
warmer...as we won`t be battling the gusty winds of previous days.

Southerly return flow develops late Friday as high pressure slides
to our southeast. Rapid warm-up with highs Saturday 15-20 F above
normal. Despite the anamolous warmth, highs Saturday still 10 F or so
below records.

Weak upper-level disturbance approaches late Saturday into Sunday
morning. Some very light precipitation is possible across Central VA
and perhaps into N VA during this period. All liquid as low
temperatures well above freezing.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
In the wake of the departing southern stream low, a deep
amplified ridge of high pressure will build. This will be the
primary weather feature for Sunday and Monday, providing sunny
skies and anomalously warm temperatures.

Northern stream shortwave energy will flatten the 500 mb ridge
axis somewhat by Tuesday as a frontal system approaches. Cold
advection looks limited, as much of the moisture and forcing
remains confined to the Great Lakes/southern Ontario to New
England/southern Quebec, but temperatures may ease down a few
degrees Tuesday and Wednesday as clouds increase and small PoP
chances surface.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
While predominantly VFR conditions prevail through Saturday
night...gusty NW winds will continue through this evening. A few
scattered flurries or snow showers are possible into this
afternoon as well, with the potential for localized and brief
sub-VFR conditions. Gusts of ~25-30 knots likely through late
this afternoon...before wind gusts subside by this evening.
Relatively light winds Friday and Saturday.

VFR flight conditions should persist Sunday and Monday under
building high pressure.

&&

.MARINE...
SCA criteria gusts ongoing across much of the waters. Despite
increased mixing depth through the morning...wind field weakens
enough to keep gusts mostly high-end SCA. Winds lessen tonight.
Light winds expected Friday and Saturday with high pressure
nearby.

There may be a little burst of wind Sunday in the wake of passing
low pressure. However air temperatures will be substantially warmer
than the 40 degree water, which will prevent mixing. Otherwise
winds will be 10 kt or less under building high pressure.

&&

.FIRE WEATHER...
Conditions may become marginally favorable for an enhanced
threat for the spread of wildfires across central VA for a few
hours during the afternoon...as RH values bottom out between
25-30% with reduced fuel moisture. Limiting factors are winds
and temperatures...as sustained winds across this area expected
to remain near 10 kts (gusts 15-20 kts) with high temperatures
in the lower 40s.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...Winter Weather Advisory until 10 AM EST this morning for
     WVZ501-505.
MARINE...Small Craft Advisory until 1 AM EST Friday for ANZ530>533-
     538>542.
     Small Craft Advisory until 4 AM EST Friday for ANZ534-537-543.
     Small Craft Advisory until 7 PM EST this evening for ANZ535-
     536.

&&

$$
SYNOPSIS...MSE
NEAR TERM...MM/MSE
SHORT TERM...MSE
LONG TERM...HTS
AVIATION...MM/MSE/HTS
MARINE...MM/MSE/HTS
FIRE WEATHER...MSE



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