Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 290719
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
319 AM EDT Thu Jun 29 2017

.SYNOPSIS...

High pressure will settle near Bermuda Thursday with hot and
humid conditions returning and persisting through the first half
of next week.

&&

.NEAR TERM /TODAY/...

High pressure - which was responsible for chilly conditions
Wednesday morning and a very comfortable day, is now centered
just east of Norfolk. This will continue to drift east, and wind
field will turn to the south today, allowing temperatures to
rise back to late June norms. Highs this afternoon should reach
the mid to upper 80s.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...

Temperatures more typical for the end of June/early July will
persist into Saturday. Outside of the higher elevations
temperatures will approach 90 both afternoons with lows near 70.

Precipitation chances will be slim in the next 48 hours -
perhaps some orographically induced showers/thunderstorms Friday
afternoon/evening, but the best chance will be Saturday
afternoon. Low pressure over Ontario/Quebec with a cold front
dropping into NY state and a weak trough approaching the
mountains will serve as the focus for storms. Bufkit profiles
show a weak unidirectional wind field, so at this moment pulse
severe looks to be the worse case scenario.

With summer precipitation forecasting I am usually hesistant to
go beyond "chance" five periods out. Given we have been
advertising "likely" in the west as our surrounding offices, and
GFS is forecasting 70 PoPs I`ll hold with the 60 PoP Saturday
afternoon west of the Blue Ridge.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...

Typical summertime conditions expected for late in the weekend and
into next week with daily chances for afternoon/evening convection
and very warm temperatures.

A weakening frontal boundary that approaches Saturday will stall
near the region Saturday night into Sunday, keeping chances for
showers and thunderstorms in the forecast. This boundary will remain
near or just north of the area into next week, separating a
hot/humid air mass to the south from a cooler Canadian air mass to
the north. Thus there will be chances for isolated/scattered
showers/thunderstorms each day, but the vast majority of the time
should be dry.

Will show highs upper 80s to low 90s through the period for now,
with lows in the 60s/70s, but will be dependent on frontal
position.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...

VFR conditions today through midday Saturday. Showers/
thunderstorms will be possible Saturday afternoon, especially at
IAD/MRB/CHO.

Mainly VFR expected through at least Monday. Isolated-scattered
showers/thunderstorms possible, so some brief reductions are
possible.

&&

.MARINE...

Southerly channeling currently occurring on the Bay/lower
Potomac - a sure sign of summer. With daytime heating this will
expand to include all waters after sunrise, then return to its
current state tonight.

This will likely reoccur Friday into Saturday.

Mainly Sub-SCA conditions expected Saturday night through Monday.
There is a chance for isolated-scattered showers/thunderstorms each
afternoon and evening, which may contain locally gusty winds.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 AM EDT Friday for ANZ530>534-
     537>541-543.
     Small Craft Advisory from 10 AM this morning to 8 PM EDT this
     evening for ANZ535-536-542.

&&

$$
PRODUCTS...WOODY!/MJM



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