Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

000
FXUS61 KLWX 242202
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
602 PM EDT TUE MAY 24 2016

.SYNOPSIS...
A ridge of high pressure will build south of the region through
the remainder of the week and into the weekend. A low pressure
system may affect the region late in the weekend and into early
next week.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Cu field will diminish this evening due to the loss of daytime
heating. High pressure will build toward the region
tonight...bringing dry and seasonable conditions.

Mostly clear skies and light winds are expected for the overnight
hours. Patchy fog likely in a few areas, especially north and
west, but low levels are drying considerably, and crossover
temperatures will struggle to be met, so widespread fog not
expected. Lows generally 50-60F.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Mostly sunny, warm, and dry weather will be the theme on Wednesday
as ridge of high pressure dominates. Will be a weakening remnant
vort/shortwave approaching from the west during the day, but
instability will be lacking as moisture return is slow to occur,
so only have a slight chance in the higher elevations of the far
western counties. Highs will be in the mid 80s pretty much area-
wide, with relatively low humidity as dew points hold in the 50s.
Wednesday night will also be dry, lows upper 50s to mid 60s.

Thursday will see more in the way of moisture return with dew
points rising back into the low/mid 60s. This will lead to the
development of some isolated to scattered showers/thunderstorms,
especially in the higher terrain. Very weak wind field aloft
though, so organized severe not expected. Temperatures warm a few
more degrees with highs in the mid/upper 80s. A few showers/storms
may linger into Thursday night. Mild night in store with lows in
the 60s for all.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Remaining hot (U80s) and humid (U60s Tds) Friday with chances for
isolated afternoon thunderstorms in the moderate instability, very
low CAPE environment. Thunderstorm coverage will be greatest where
orographic forcing helps with convective initiation. With weak
steering flow, activity will have a difficult time moving off the
higher terrain, though there could be a storm or two east of the
Blue Ridge that develops due to localized influences.

Saturday looks dry across most of the area, as poor mid-level lapse
rates develop, with mid/upper ridge extending further north into the
area. This keeps any shower and storm activity confined to the west
over the higher terrain. Temperatures/dewpoints cool a few degrees
from Friday.

Changes begin to develop late Saturday into Sunday as low over the
Atlantic approaches the eastern seaboard from the SE. While ultimate
track of the system is uncertain at this time, precipitation shield
ahead of system could begin to impact the area as early as Sunday
and continue into early next week. Onshore flow and cloud cover
ahead of system will also help to cool temperatures back below
normal.

&&

.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
Predominantly VFR through at least Thursday night. Some fog may
bring some reductions late tonight, early Wednesday morning, but
have left VFR for now as coverage will be patchy. Will also be
some isolated-scattered showers and thunderstorms around on
Thursday which may bring some brief reductions...but coverage will
be scattered at best. Winds out of the northwest this afternoon
with gusts up to about 17 knots become light and locally variable
tonight, before turning light south/southwest Wednesday through
Thursday night (less than 10 knots).

While most of Friday will end up VFR, could be a few isolated storms
with sub-VFR possible in and around any activity.

Uncertainty increases Sunday as coastal low approaches the eastern
seaboard, though rain chances (and associated sub-VFR) possible as
early as Sunday.

&&

.MARINE...
Winds will diminish this evening due to the loss of mixing from
daytime heating. Lighter winds are expected through Thursday
night. May be a few isolated- scattered thunderstorms on Thursday.

Flow remains sub-SCA Friday and Saturday, though there is a low-
end chance for a thunderstorm over the waters Friday.

&&

.CLIMATE...
We put together some records (preliminary) of how this month compares
to rainy Mays on record for our area.

Washington, DC (records since 1871)
Most days in May with at least a trace: 25 (in 1952
and 1943) So far in 2016 (through 2PM EST on the 24th): 20

Most days in May with at least 0.01": 20 (in 2003)
So far in 2016 (through 2PM EST on the 24th): 18

Highest May monthly rainfall: 10.69" (in 1953 and 1889)
So far in 2016 (through 2PM EST on the 24th): 5.22"

Baltimore, MD (records since 1870)
Most days in May with at least a trace: 25 (in 2003)
So far in 2016 (through 2PM EST on the 24th): 20

Most days in May with at least 0.01": 21 (in 1882)
So far in 2016 (through 2AM EST on the 24th): 17

Highest May monthly rainfall: 8.71" (in 1989)
So far in 2016 (through 2PM EST on the 24th): 4.92"

Dulles, VA
Most days in May with at least a trace: 23 (in 2003)
So far in 2016 (through 2PM EST on the 24th): 21

Most days in May with at least 0.01": 21 (in 2003)
So far in 2016 (through 2PM EST on the 24th): 17

Highest May monthly rainfall: 10.26" (in 2009 and 1988)
So far in 2016 (through 2PM EST on the 24th): 6.07"

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for
     ANZ530>543.

&&

$$
SYNOPSIS...MM
NEAR TERM...BJL/MM
SHORT TERM...MM
LONG TERM...MSE
AVIATION...MM/MSE
MARINE...BJL/MM/MSE
CLIMATE...DFH



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.