Area Forecast Discussion
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FXUS61 KLWX 210048
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
848 PM EDT Wed Jul 20 2016
High pressure centered over the Mid Atlantic tonight will drift offshore
Thursday. A front will sag into the area Friday night before
stalling to our south over the weekend. High pressure will be in
control of the area weather Saturday through Monday. A weak front
looks to enter the area Monday night and linger just south of the
area into the midweek.
.NEAR TERM /THROUGH THURSDAY/...
High pressure shifts east offshore Thursday with a southerly return
flow developing in the afternoon across the area. Moisture
returns. Max temps around 90F with dewpoints rising to the mid
60s, just a couple degrees heat index. 850mb temps rise to 20C
west of the Blue Ridge by 00Z Friday, closer to 17C east at that
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
Tranquil Thursday night with high pressure still over the region.
Light Sly flow with a warmer night than tonight, upper 60s inland
and mid 70s nearshore.
Low pressure tracks east across northern Quebec Friday into
Friday night. Associated cold front will be quite strung out by
the Mason-Dixon line Friday evening. Ahead of this front, expect
850mb temps to increase to 20 to 22C with max temps mid 90s, upper
90s possible in best mixing. Dewpoints mid to upper 60s with heat
indices around 100F in the coastal plains. May need a very
targeted heat advisory for urban centers.
PoPs delayed to Friday evening with the weak forcing from the cool
front enough to cause scattered thunderstorms. Severe
thunderstorms are possible any time the temperature reaches the
mid 90s with dewpoints in the 60s. Any activity should wane in the
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Extended stretch of hot and humid weather over the weekend into at
least early next week as broad ridge that has been across the CONUS
noses into the mid-Atlantic. High temperatures near 100F combined
with dewpoints AOA 70F will combine to create heat index values near
105F...with heat related headlines possible during this time. Urban
areas will also see little nighttime relief as lows remain well into
U70s in the humid airmass. Shower/Thunderstorm chances remain low
over the weekend...with best chances with terrain induced
Vort max passes well to our north Monday into Tuesday...allowing for
H5 heights to fall some and for a cold front to approach the area.
While the uncertainty regarding how far cold south front makes into
our area is rather high, nearby frontal boundary could allow for
some afternoon/evening showers and thunderstorms Monday and
Tuesday, which could provide some relief from the heat.
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
VFR through Friday night under high pressure that builds tonight
and lingers offshore Thursday afternoon through Friday night. Best
fog chances tonight, though not expected to be more than ground
fog at TAF sites.
VFR prevails this weekend through early next week under high
pressure. Thunderstorm chances are low over the terminals during
High pressure builds southeast across the area through tonight.
NE wind 5-10kt in advance. Light return southerly flow begins
Thursday afternoon. Southerly flow continues through Friday night.
Channeling may require an SCA Friday afternoon into the night.
High pressure in control over the weekend, with southerly channeling
developing overnight leading to elevated winds near SCA criteria.