McLean, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

696
FXUS61 KLWX 151430
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1030 AM EDT Tue Jul 15 2025

.SYNOPSIS...
A frontal boundary will remain nearly stationary today before
lifting northward as a warm front on Wednesday. Another cold
front moves through the region late Friday before stalling
nearby through the weekend and into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
*10:30 AM UPDATE*
Relative to 24 hours ago, the IAD sounding indicated a decrease
in precipitable water (PWAT) values over the area. The July 14
(12Z) PWAT was 2.14", with a drop to 1.83" this morning. While
the low levels remain moist as evidenced by the high dew point
air mass, the biggest change is the drying of the 500-250 mb
layer. Given the southward shift in the tropical air mass,
expect the better chance for organized heavy rainfall closer to
the I-64 corridor. With that in mind, have added a Flood Watch
(for flash flooding) across Augusta, Nelson, and Albemarle
counties, which includes the central Virginia Blue Ridge. This
is in effect from 2 PM until midnight with rainfall rates up to
1.50 to 2.50 inches per hour possible in the heavier cores. Most
notably, the biggest concern would be across the higher terrain
which have recently seen heavy rainfall.

*PREVIOUS DISCUSSION*
A frontal system slowly moves through the forecast area this
morning before stalling across the northern portions of the area
this afternoon. Warm and humid conditions continue today with
high temperatures in the mid to upper 80s. Heat indices will
rise into the low to mid 90s across much of the area.

Diurnally driven showers and thunderstorms are expected this
afternoon and will be less organized compared to yesterday.
Given the lack of forcing and lack of steering flow, pulse
convection will lack movement and will be capable of producing
heavy rainfall. With PWATS nearing or exceeding 2" combined with
previous rainfall in days prior, there is a risk of flash
flooding. WPC has a slight risk for excessive rainfall across
portions of the area.

Patchy fog is possible again overnight as humid conditions
continue with light winds. Overnight low temperatures will be
in the mid to upper 60s for those west of the Blue Ridge and in
the 70s for those east of the Blue Ridge.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
The aforementioned boundary is forecast to slowly lift northward
as a warm front on Wednesday before dissipating. While showers
and thunderstorms are expected each day, Wednesday looks to be
the more active of the two days as the front remains nearby.
High temperatures on Wednesday will be in the 80s to low 90s
with heat indices rising into the upper 90s to 100. Overnight
low temperatures will be in the 70s for most.

Precipitation linger on Thursday, with diurnally driven showers
and thunderstorms remaining possible. Temperatures warm under a
tropical airmass with highs in the upper 80s to mid 90s. With
humid conditions expected, heat indices near Heat Advisory
Criteria along the I-95 corridor. Overnight lows will stay in
the 70s for most.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Some shower and thunderstorm activity could develop in the
western and parts of the central zones midday Friday and Friday
afternoon as a cold front slides southeast across the region.
Otherwise, convection should fade some and slide southward by
Friday evening and night. High temperatures should be in the
lower 90s.

A couple of showers and a thunderstorm could linger or pop up on
Saturday with the heating of the day, mainly across the southern
half of the region. A weak area of high pressure could push into the
region and bring some slightly drier air into the region late
Saturday into Saturday night. High temperatures should reach the
middle to upper 80s.

Dry conditions could linger through midday Sunday with high pressure
still holding on. A slight upslope component to the wind in the
mountains in the west, followed by a developing warm front, could
spawn a few showers or a thunderstorm during the warmest time of the
day on Sunday and into Sunday evening. Highs in the upper 80s.

Showers and thunderstorms, once again, could become more widespread
Monday afternoon and evening with a low pressure system moving
across Pennsylvania and a trailing cold front pushing southeast
toward our region. Highs in the upper 80s to lower 90s.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
A cold front remains stalled overhead today before lifting
northward as a warm front tomorrow. This will lead to daily
shower and thunderstorm chances with Wednesday expected to be
the more active day. Flight restrictions are expected during
showers and thunderstorms.

Light winds out of the south are forecast across all terminals
today before becoming light and variable overnight. Winds
increase on Wednesday, gusting 15 knots out of the south in the
afternoon. Winds shift to southwesterly on Thursday, gusting 15
knots or less.

VFR conditions should start the day Friday, but MVFR to IFR
conditions may develop Friday midday through Friday afternoon at any
of the terminals. Once convection clears Friday evening and at
night, VFR conditions should redevelop. Winds southwest to west 5 to
10 knots. VFR conditions expected for the most part at all terminals
as a weak area of high pressure influences slightly drier
conditions. A few showers or a thunderstorm could move over CHO
Saturday afternoon and evening, but shouldn`t be too overbearing.
Winds becoming northwesterly 5 to 10 knots with light and variable
winds across the southern areas

&&

.MARINE...
Showers and thunderstorm chances continue over the waters each
afternoon and evening with SMWs possible today and Wednesday.
Precipitation chances decrease slightly on Thursday, though the
risk lingers for storms over the waters. Winds increase to near
SCA criteria Wednesday evening due to southerly channeling. A
Small Craft Advisory may be needed. Southerly winds continue
through Thursday with Small Craft Advisories possible again on
Thursday.

The only marine hazards that could occur Friday into Friday evening
would be Special Marine Warnings for thunderstorms that could
develop and move out over the Potomac River and Chesapeake Bay
waters Friday afternoon and evening. Winds generally southwest to
west 10 knots with exception to higher gusts in thunderstorms. No
marine hazards expected Saturday and Saturday night. Winds
becoming more northeast 10 knots.

&&

.TIDES/COASTAL FLOODING...
After a brief lull in the warm advection flow regime, expect a
return to the prolonged period of southeasterly winds. This will
lead to elevated tidal anomalies through midweek, particularly
across Annapolis. This location will see Action stage at
times, particularly during the higher of the two astronomical
high tide cycles. However, outside of freshwater influences from
heavy rainfall, the threat for tidal flooding appears low.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...Flood Watch from 2 PM EDT this afternoon through this evening
     for VAZ025-036-037-508.
WV...None.
MARINE...None.

&&

$$

SYNOPSIS...AVS
NEAR TERM...AVS/BRO
SHORT TERM...AVS
LONG TERM...KLW
AVIATION...AVS/KLW
MARINE...AVS/KLW
TIDES/COASTAL FLOODING...BRO