Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

077
FXUS61 KLWX 061414
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1014 AM EDT Sun Oct 6 2024

.SYNOPSIS...
Mostly sunny skies continue today with increasing clouds late as a
strong cold front approaches from the Ohio River Valley. The front
will cross the area late tonight into Monday morning bringing a few
showers and perhaps a thunderstorm. Breezy conditions are expected
Monday afternoon and evening in the wake of the front as high
pressure builds over the region. High pressure will remain in
control with below normal temperatures Tuesday through late
week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Patchy valley fog mainly west of the Blue Ridge and over the high
valleys of the Alleghenies continues to slowly burn off through 11am
this morning. Elsewhere mostly sunny skies prevail as high pressure
pushes off the southern New England and Mid-Atlantic coast. High
pressure will continue offshore this afternoon as a strong cold
front approaches from the Ohio River Valley. The front will bring
increasing clouds late with the potential for showers and a few
thunderstorms mainly west of I-81 corridor.

Mostly sunny and dry conditions will continue in most locations
through this evening with the front expected to arrive late tonight
into Monday morning. Locations west of a line from Cumberland, MD
down to Franklin, WV will likely see cloud cover build in later this
afternoon after 20z/4pm. Showers and thunderstorms will pull into
far western MD and the mountains of eastern WV during the 7-10pm
timeframe. 12z CAM guidance shows convection initializing up around
Cleveland, OH and Erie, PA between 4-7pm before advancing toward
Pittsburgh, PA and Morgantown, WV between 6-9pm. Beyond this point,
models bring convection into western Garrett, Grant,Hardy, and
Allegany Counties between 8-11pm. CAPE values will hover between 300-
700 j/kg with 0-6km bulk effective shear values around 35-45 kts.
SPC continues to highlight areas along and west of the Alleghenies
for a Marginal Threat (Level 1 out 5) for severe weather. The
general focus amongst the 12z CAMS remains across western PA and
north-central WV where the highest CAPE and shear will be maximized.
Damaging winds and hail appear to be the primary threats with any
severe storms that can get going later this evening and into the
front half of the overnight period. This activity will continue to
weaken as it crosses the mountains after midnight and into early
Monday morning. The highest probabilities for precipitation east of
mountains tonight into Monday morning looks to be in areas along and
north of I-66/US-50 where a stray shower or thunderstorm cannot
be ruled out. High temperatures today in the mid to upper 70s
and low 80s under light south to southwesterly flow. Low
temperatures tonight will range from the upper 40s in the
mountains to the mid 60s across southern Maryland.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
The beginning of the work week kicks off a pattern of quieter
weather for the area. The cold front and associated precip will
swiftly exit early Monday morning and high pressure builds in
behind it with mostly sunny skies. With building high pressure,
the tight pressure gradient will result in breezy conditions,
northwest winds gusting 20-25 mph. As cooler air advects in,
high temperatures are only expected to reach the upper 60s to
mid 70s, and 50s in the mountains.

Tuesday will be similar, temperatures dropping a few more
degrees and winds diminishing slightly as the colder air mass
settles in. Highs in the upper 60s and low 70s will be near to
slightly below normal.

Low temperatures both nights drop into the 40s for most of the
area. Frost is possible in the mountains as temps drop into the
mid-upper 30s.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
High pressure will gradually build in from the Great Lakes Wednesday
into Thursday as a deep upper trough initially located over the
Northeast/Quebec progresses eastward toward the Canadian Maritimes.
Northwesterly winds are expected during that time ahead of the
approaching high, which will maintain a cool and dry airmass over
the region. Mostly sunny skies are expected both days, along with
high temperatures in the 60s. The high will build overhead Thursday
night, setting the stage for ideal radiational cooling conditions.
Low temperatures will be in the 30s and lower 40s for most, and
frost/freeze headlines may potentially be needed for portions of the
area.

Flow aloft will turn more zonal in nature, and the surface high will
move to our south late in the week into next weekend. This will
cause winds to turn southwesterly, which will advect a warmer
airmass into the region. In the absence of any notable upper air
features, sunny skies and dry conditions are forecast, along with a
gradual warming trend in temperatures. Highs on Friday are expected
to be near 70, with mid 70s on Saturday. Overnight lows will
generally be in the 40s Friday night, with upper 40s and lower 50s
Saturday night.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
Prevailing VFR conditions are expected for the remainder of the
afternoon across the terminals. Generally looking at SKC
conditions with a few low/mid level clouds passing along and
east of the corridor terminals as well as over the mountains.
Winds will remain light out of the south and southwest at 5 to
10 kts.

This evening, a cold front approaches from the NW, and
associated showers and thunderstorms are expected to diminish
east of the mountains. As such, the greatest chances of
precipitation with this frontal passage are west of MRB, but
isolated to scattered showers (and maybe thunderstorms) are
possible for MRB (10PM- midnight) and BWI/MTN (midnight-4AM).
Sub-VFR conditions are possible but confidence wasn`t high
enough to include in TAF explicitly. As the front exits early
Monday morning, any reductions should improve quickly.

High pressure builds in Monday into Tuesday, with mostly sunny
skies and NW winds gusting 15-20 kts. VFR conditions and
northwesterly winds are expected on both Wednesday and
Thursday.

&&

.MARINE...
A cold front crosses the waters tonight into Monday. Winds
strengthen out of the south before the frontal passage tonight,
and Small Craft Advisories are in effect for the Chesapeake Bay
and the lower tidal Potomac from 8PM tonight through 6AM Monday
morning.

Behind the front, gusty NW flow could necessitate further SCAs.
Winds likely diminish by Tuesday. Northwesterly winds are expected
over the waters on both Wednesday and Thursday, with gusts to
around 15 kt possible at times.

&&

.TIDES/COASTAL FLOODING...
Southerly flow today should allow tidal anomalies to increase once
again. No flooding is anticipated during the day today, but
Annapolis and DC SW Waterfront may come close to flooding tonight.
Winds will turn northwesterly behind a cold front later tonight into
early Monday morning. A prolonged period of offshore flow is
expected thereafter, which should lead to lower tidal anomalies and
a reduced threat for coastal flooding.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 8 PM this evening to 2 PM
EDT Monday for ANZ530>534-537-539>541-543.

&&

$$

SYNOPSIS...EST
NEAR TERM...EST
SHORT TERM...CAS
LONG TERM...KJP
AVIATION...KJP/CAS
MARINE...KJP/CAS
TIDES/COASTAL FLOODING...KJP