Area Forecast Discussion
Issued by NWS Sterling, VA
FXUS61 KLWX 200053
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
853 PM EDT THU MAY 19 2016
High pressure will build over the area through Friday morning.
Low pressure will track east across North Carolina Friday night
before turning up the Mid-Atlantic coast Saturday. Upper level
low pressure will persist along the Mid-Atlantic coast Saturday
night through Monday night. High pressure then builds overhead
through Tuesday night before shifting offshore.
.NEAR TERM /TONIGHT/...
A beautiful evening is underway - clear skies and comfortable
temperatures. 00Z IAD sounding shows majority of drying in past
twelve hours has been in the lower levels.
Near calm, clear skies, and residual surface moisture will result
in valley fog after midnight. Lows tonight mid to upper 40s
inland tonight, low to mid 50s near shore.
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Upper level trough tracks east across the Midwest states Friday
into Friday night. Surface low pressure develops over NC Friday
night reaching the northern outer banks during Saturday morning.
An east wind will develop across the CWA Friday night with
subtropical moisture converging ahead of the upper low. 100 POPs
spread east across the CWA through the night.
Bulk of rain from this event falls Friday night with widespread
moderate rain over the southern 2/3 of the CWA. Moderate rain
continues east of Interstate 95 Saturday morning. Wrap around NEly
flow keeps clouds and light rain across the area into Saturday
evening. Total QPF 0.5 inch along Mason-Dixon line to 1.5-2
inches over central VA with 0.75 to 1.25 inches between. Will need
to monitor eastern slopes of the Blue Ridge Mountains, but this
should be just a soaking rain with no flood hazards. The low
clouds keep high temperatures down, around 60 degrees.
North wind and clouds as upper trough enters the area Saturday
night. Rain should generally taper off through the night. Lows in
the upper 40s inland to low 50s near shore.
.LONG TERM /SUNDAY THROUGH THURSDAY/...
A slow moving upper-level low will spiral about just offshore of the
Mid-Atlantic through the first half of next week while slowly
weakening. A few showers are possible Sunday afternoon and again
Monday afternoon during daytime heating and aided instability from
the nearby upper low. But as the low weakens and pulls east Tuesday
into Wednesday, gradual height rises should squash any showers
leading to a drying and warming trend.
Upper-level ridging will build in the wake of the departing upper
low with a surface high establishing itself off the southeast coast
for the second part of next week. This should lend to a more summer
like pattern with warmer and more humid air and pop up showers or
thunderstorms during the afternoon and evening hours.
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
VFR conditions tonight as high pressure builds over the area with
light and variable flow. Clear and nearly calm conditions will
result in at least valley fog late tonight through sunrise Friday.
VFR then rest of Friday with light SEly flow developing.
Widespread rain spreads east Friday night with moderate rain and
IFR conds expected for KCHO and into DC Metros early Saturday
morning. NEly flow and light rain then lingers across the area
into Saturday evening as low pressure moves up the Mid-Atlantic
Sub-VFR possible in lingering showers under upper level low
pressure Saturday night into Sunday night. Winds will be
northerly around 10 knots Sunday into Monday.
Light north winds through the evening as high pressure builds from
the northwest. SEly flow develops Friday behind the high. Low
pressure passes south Friday night, turning up the Mid-Atlantic
coast Saturday. NEly flow increases to SCA range late Friday
night, lingering into Saturday night.
Northerly channeling behind departing low pressure to the
east and approaching high pressure from the west could result in
Small Craft Advisory level wind gusts lingering over at least
portions of the waters through Sunday.