Area Forecast Discussion
Issued by NWS Sterling, VA
FXUS61 KLWX 200040
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
840 PM EDT SUN JUN 19 2016
High pressure will remain over the area through Monday. A cold
front will cross the region on Tuesday. High pressure will press
in from the north briefly on Wednesday before another storm system
crosses the area from northwest to southeast on Thursday. High
pressure will return for the start of next weekend.
.NEAR TERM /THROUGH MONDAY/...
Surface high pressure is centered across the VA/NC border this
evening. Few to scattered mid-high level clouds will move across
the region tonight. Otherwise, light winds expected tonight with
some patchy fog in sheltered valleys.
Through Monday, a trough will push east across southern Canada and
the far northern United States...reaching near Lake Huron by early
Monday night. The closed low will meander off the coast. In
between...the ridge will be squeezed over us but remain intact.
Thus...little if any weather is expected through Monday afternoon.
As has occurred the last few mornings...the light winds and clear
skies may result in patchy valley fog across western
Virginia...western Maryland and eastern West Virginia late tonight
and early Monday. Temperatures will warm a little more aloft thru
the next 24 hours...so both lows tonight and highs on Monday
should end up a little warmer than last night/today.
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
A pseudo warm front appears to move across the region Monday
night. Combined with falling heights...and this may cause showers
and a few thunderstorms to break out. Lows will stay sultry with
the increased humidity and cloud cover.
Short-wave will dive into the base of the long-wave trough on
Tuesday. At the same time...the surface cold front will advance
into the area. Latest guidance is perhaps a bit slower with the
front...and temperatures thus look a bit warmer. In
addition...this suggests the risk of thunderstorms across much of
the CWA may last longer. Severe weather is a possibility...however
the overall flow aloft is pretty westerly and this has in the past
resulted in guidance over-doing the expected convection.
Nevertheless...SPC has a slight risk over our southwestern zones
for Tuesday and if the westerly flow is insufficient to cap
it...severe convection is definitely possible.
Front slides south Tuesday night and stays south Wednesday morning
as high pressure nudges south from Canada...however the front may
start nudging back northward by the end of the day Wednesday. We
should dry out Tuesday night...but showers may return to
southwestern zones as early as Wednesday afternoon. At this point
think thunder will be minimal with the more stable air mass in
place and cooler temperatures expected.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Area of high pressure moves to the East Coast Thursday, while low
pressure develops over the Ohio Valley and moves across our region
Thursday night. There is a chance for showers and thunderstorms
Thursday through Thursday night. At the present time, it appears
that the models are favoring the track of the low to be through
the middle of our forecast area. The threat for heavy showers and
a couple of thunderstorms will be present. Temperatures will be
The low pressure system should move offshore Friday. However,
wrap- around showers or a rumble of thunder could linger right
into midday Friday. Upper level energy will be swinging in from
the northwest around the main low. High pressure will begin to
work its way into the region Friday night and linger through the
The high will move offshore Sunday. A southerly return flow
should develop in its wake to feed moisture northward for the next
storm system Sunday night into early next week.
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
VFR with light winds thru next 24 hours all terminals.
Thunderstorms may start to impact the terminals at some point
Monday night but more likely Tuesday. CIGS and VIS may be
reduced...possibly briefly to IFR if a heavy enough storm hits a
terminal directly. VFR returns Wednesday but more rain/t-storms
will promise potential reductions again Thursday.
Light winds with dry weather on the water through the next 24
hours. Most likely any showers and thunderstorms...and gusty winds
ahead of the next cold front...will hold off until later Monday
night and Tuesday, but by then a SCA is definitely possible.
Quieting down Wednesday but another system may kick up the winds
and bring more showers/t-storms on Thursday.