Aspen Hill, Maryland 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

091
FXUS61 KLWX 311339
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
939 AM EDT Thu Jul 31 2025

.SYNOPSIS...
A cold front will slowly move across the mid-Atlantic today
through Friday. Strong high pressure will build into the area
over the weekend, bringing below normal temperatures and
humidity. High pressure weakens into next week while the next
front is expected to slowly approaches from the south. Rain
chances return by the middle of next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
Excessively humid conditions are being observed across the
region with dew points well into the 70s to near 80 and PW in
excess of 2 inches (even 70+ Tds over the higher terrain). This
will fuel thunderstorms with very heavy rain beginning in a few
hours (roughly midday onward).

A cold front will sag south into our region today. A strong
shortwave trough will move over our area this afternoon and
evening. A persistent southerly flow will provide deep tropical
moisture to help fuel numerous heavy showers and strong to
severe thunderstorms this afternoon and evening. Dewpoint
temperatures in the low to mid 70s will result in revealing
PWATs of 2.2 to 2.3 inches. One final day of hot and humid
conditions today with the developing convection. Highs are
forecast to be in the upper 80s to low 90s, with peak heat
indices between 95-105.

Heavy rainfall leading to flash flooding is going to be a major
concern for portions of the area. Thunderstorms will be capable
of producing torrential downpours due to high PWATs and
efficient warm cloud processes. Some areas could see multiple
rounds of storms with high res models indicating slow moving/erratic
thunderstorms in the early afternoon, then the main convective
push moves through mid afternoon to early evening. The focus
area looks to be east of the Blue Ridge and along/north of
US-50/I-66. These are the regions where widespread rainfall
amounts of 1-2" are expected, with localized higher amounts of
4-6" possible. This could result in numerous instances of flash
flooding, especially in urban areas where it could be significant.

Showers/thunderstorms will develop by early afternoon, with the
heaviest rainfall most likely between 1PM to 6PM west of the Blue
Ridge, and 3PM to 8PM to the east. A Flood Watch remains in
effect for portions of the Shenandoah Valley, northern/central
Virginia, and most of Maryland from Washington County eastward.
A Moderate Risk ERO with WPC that will cover the entirety of
the DC and Baltimore Metro areas and goes up into PA/NJ remains
the main message of today`s active weather. It is extremely
important for those traveling during this evening`s commute to
be aware of possible flooding. Do not drive through flooded
roadways, find an alternate route to your destination, or avoid
driving during the worst of the weather. Remember --> Turn
Around, Don`t Drown!

Heavy showers and thunderstorms are possible elsewhere, though
coverage and motion of convection will be a bit faster.

There will be plenty of instability to sustain thunderstorms
through the day, though the severe threat looks limited due to
high freezing levels and weak mid-level lapse rates. Localized
damaging wind gusts will be the main threat from any severe
thunderstorm that develops. Abundant cloud cover could also work
against a more widespread severe threat.

Convection wanes later this evening as the front slowly
continues to drift south. On and off showers will be possible
overnight into early Friday.

The leading edge of the front pushes south of the area by Friday
morning, as is noted with the surge of northerly winds across the
area. However, the anafrontal nature of this system will keep
overrunning showers around for most of the day on Friday. As a
result, high temperatures are forecast to be well below normal - in
the mid to upper 70s. A reinforcing trough moves across the area
Friday evening and finally scours out any lingering precip. Much
drier and cooler air surges in Friday night, dropping temps to the
50s to low 60s.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
A reinforcing trough of low pressure moves across the area
Friday evening and finally scours out any lingering precip. Much
drier and cooler air surges in Friday night, dropping temps to
the 50s to low 60s.

Saturday will remain below average but not as cool as Friday.
Highs near 80 in the eastern half of the region. Dry Saturday
into Saturday night in part to high pressure.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Cooler, drier, and less humid conditions are expected during the
long term period.

High pressure will build to our north for Sunday and Monday,
resulting in light onshore flow at the surface. Mostly sunny skies
are expected both days, along with below normal temperatures and low
humidity levels for early August. Highs will be in the upper 70s to
mid 80s and lows will be in the 50s and lower 60s for most.
Precipitable water values will drop to under one inch, and dewpoints
will hold in the 50s.

High pressure is expected to progress off the New England Coast by
Tuesday and Wednesday, while weak upper troughing starts to
approach from the west. High temperatures are forecast to reach into
the low to mid 80s, with lows generally in the 60s. Dewpoints will
gradually start to climb back into the lower to middle 60s, while
precipitable water values increase back above one inch. Dry
conditions are expected for most, but an afternoon shower or
thunderstorm can`t be ruled out, especially on Wednesday.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
A cold front will sag south into the area today, bringing
numerous showers and thunderstorms this afternoon and evening.
These storms are likely to produce periods of sub- VFR
conditions at all terminals. This looks to be most likely
between 19Z Thu to 00Z Fri, though some adjustments are likely
needed as new guidance comes in.

The front will be slow to push through the area, likely being
overhead tonight through much of Friday. As a result, sub- VFR
conditions are likely due to low stratus and maybe some vsby
reductions due to showers/drizzle in the area. The front finally
clears the area Friday night with VFR conditions returning.

VFR conditions and light easterly winds are expected on both Sunday
and Monday.

&&

.MARINE...
A cold front will sag south into the area this morning. This
brings numerous showers and thunderstorms this afternoon into
this evening, that will pose a threat to mariners from gusty
winds and lightning strikes. Special Marine Warnings are likely
needed for portions of the waters on Thursday.

The cold front slowly moves south tonight into Friday. SCA
conditions appear likely behind the front Friday evening into
Saturday as northerly winds strengthen.

Small Craft Advisories will likely be needed on Saturday as
northeasterly winds gust near 20 knots over the waters. Winds
diminish overnight, although Small Craft Advisories remain possible
in the southern portions of the waters overnight.

Sub-SCA level easterly winds are expected on both Sunday and
Monday.

&&

.HYDROLOGY...
A cold front is expected to slowly push southeastward over the
next 12 to 24 hours. This front will push to the south later
this evening and overnight, but not before leaving a mark in the
region of possible severe thunderstorms, as well flooding
rainfall. Multiple rounds of showers and thunderstorms are
possible. A quick 1 to 2 inches of rain in 30 minutes is
possible in the stronger cells. Given many storms will be slow
movers, 2 to 4 inches of rain is possible within a couple hours.
Flash flooding will become more likely in these areas. While it
is difficult to say with confidence where the heaviest rain
will set up, some locations could see a worst case scenario of 4
to 6 inches of rain. A Flood Watch for Flash Flooding remains
in effect from 2 PM today until 2 AM Friday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Flood Watch from 2 PM EDT this afternoon through late tonight
     for DCZ001.
MD...Flood Watch from 2 PM EDT this afternoon through late tonight
     for MDZ003>006-008-011-013-014-016>018-503>508.
VA...Flood Watch from 2 PM EDT this afternoon through late tonight
     for VAZ027>031-038>040-050-051-053>057-501-502-505>507-
     526-527.
WV...Flood Watch from 2 PM EDT this afternoon through late tonight
     for WVZ051>053.
MARINE...Flood Watch from 2 PM EDT this afternoon through late tonight
     for ANZ530.

&&

$$

SYNOPSIS...KLW/DHOF
NEAR TERM...KLW/DHOF/KRR
SHORT TERM...KLW/DHOF/KRR
LONG TERM...KJP
AVIATION...KLW/DHOF/KJP
MARINE...KLW/DHOF/KJP
HYDROLOGY...LWX