-- Discussion containing changed information from previous version are highlighted. --
641
FXUS61 KLWX 021852
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
252 PM EDT Thu May 2 2024

.SYNOPSIS...
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An upper level ridge will build over the area today through
Friday. Meanwhile, a backdoor cold front will cross the area
late tonight into Friday before sinking south this weekend. A
secondary cold front and area of low pressure will pass through
the area Sunday into early next week.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
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Mostly clear skies continue this afternoon with a few high
clouds passing by and patches of fair weather cumulus bubbling
up. Temperatures are on track to reach highs in the upper 80s to
low 90s for much of the area this afternoon, and possibly tie or
break a few climate records.

A backdoor cold front slowly descends into the region this
evening, turning winds out of the N/NE and possibly bringing a
surge of winds down the Bay overnight. Low temperatures will be
in the upper 50s to mid 60s, and a little warmer in the metros.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
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Brief ridging in place on Friday begins to erode as shortwave
energy digs in from the west. The backdoor cold front slowly
advances south and banks up against the Blue Ridge on Friday,
and a low pressure system moves into the Great Lakes, bringing
an associated, stronger cold front to the region Saturday into
Sunday.

The backdoor cold front will act as a focus area for PoPs Friday
morning and afternoon (though currently only slight to chance)
before expanding eastward as the second front approaches from
the west. The best chance for showers and thunderstorms begins
Friday evening and remain restricted to near and west of the
Blue Ridge until Saturday afternoon/evening with the steadiest
rain arriving Saturday night. WPC QPF has the area getting
around an inch of rain total between Friday and Saturday with
some locally higher totals along the Alleghenies. Will continue
to monitor the flood threat.

High temperatures could get into the upper 70s to mid 80s on
Friday before we cloud up. Saturday will be far cooler in
comparison, with onshore flow and dense cloud cover keeping us
in the 60s to low 70s at best.
-- End Changed Discussion --

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
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A lingering low pressure will continue to move through the area late
in the weekend with an associated cold front. Widespread showers
will build in early Sunday with isolated thunderstorm chances.
Precipitation will be most steady early in the day with continued
chances throughout the remainder of the weekend and into early
Monday. Frontal boundaries will linger through at least midweek with
renewed shower and thunderstorms chances, especially each afternoon.
The unsettled pattern looks to stick around even into the later part
of next week.

Temperatures will start out in the low to mid 70s on Sunday before
gradually warming a few degrees each day, with mid to late week
highs getting into the mid to upper 80s to even some low 90s for the
lower elevations. Overnight lows will mostly be in the upper 50s to
low 60s.
-- End Changed Discussion --

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
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VFR conditions are expected today and most of Friday with high
pressure and fair weather cumulus. Winds have been generally
W/NW around less than 10 kts, though observed a bit stronger
with some gusts at BWI. Winds go light overnight tonight for
most of the area, but a surge of stronger winds could move down
the Chesapeake Bay with the passage of a backdoor cold front
tonight, so terminals closer to the waters could see winds pick
up back to around 10 kts.

Clouds increase through the day Friday with onshore flow and an
approaching cold front from the west. Sub-VFR cigs could reach
the terminals by Friday night, and continue through Saturday
with showers and thunderstorms as the front moves through.

Sub-VFR ceilings are possible Sunday as showers and thunderstorms
impact the terminals throughout the day. Gusty southerly winds early
on Sunday will slowly subside by the midday and remain lighter into
Monday.
-- End Changed Discussion --

&&

.MARINE...
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While background westerly winds are fairly light over the area
today, southerly flow over the waters could result in channeling
this afternoon into this evening. Winds could occasionally gust
to around 18 knots at times, but confidence for a longer
duration warranting SCAs is low at this time. A Marine Weather
Statement has been issued for the waters for now but will
continue to monitor this evening. Additionally, a surge of
stronger winds could move over the waters with a backdoor cold
front overnight tonight, but confidence is also low regarding
duration of SCA criteria gusts.

Onshore flow strengthens by Friday afternoon and SCAs are in
effect. Additional advisories will likely be needed continuing
through Saturday as low pressure and an associated cold front
approaches over the weekend.

SCAs will be possible early Sunday morning before winds diminish
through Monday. Showers and thunderstorms may impact the waters,
cannot rule out an isolated SMW, especially early Sunday.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
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Onshore flow will lead to rising water levels late Friday through
Sunday. Minor coastal flooding expected during the weekend,
especially by Saturday night. Sensitive shoreline like Annapolis and
Straits Point could approach moderate flood levels.
-- End Changed Discussion --

&&

.CLIMATE...
Well above normal temperatures are forecast today. Below is a
list of daily high temperature records.

====================================================================
       Record Daily High Temperatures for Thursday 05/02
====================================================================
  Site         Thursday 05/02  value (Year record was set)
--------------------------------------------------------------------
Record Highs Thursday 05/02

Sites                         Records/Year           Forecast High
Washington DC (DCA)               91/2018                   90
Dulles(IAD)                       88/2018                   89
Baltimore, MD (BWI)               90/2018                   93
Martinsburg, WV (MRB)             95/1942                   86
Charlottesville, VA (CHO)         91/2018                   89
Hagerstown, MD (HGR)              90/2018                   86
Annapolis, MD (NAK)               90/1992                   84


=================================================================== =

     Site Legend
------------------------
DCA area - Washington DC
BWI area - Baltimore MD                          Table Legend
IAD area - Sterling/Dulles VA               ------------------------
MRB area - Martinsburg WV                      Temperature (Year)
CHO area - Charlottesville VA
HGR area - Hagerstown MD
NAK area - Annapolis MD

Although the facilities (airports, etc.) where temperatures are
currently observed were built in the mid to late 20th century,
additional temperature records taken at nearby sites before that
extend the valid periods of record back into the late 1800s (except
for IAD, where records go back to 1960).

Record Event Reports (RERs) are only issued for the sites denoted
with a (*).

All climate data is considered preliminary until reviewed by the
National Centers for Environmental Information (NCEI).

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 11 AM to 6 PM EDT Friday for
     ANZ530>543.

&&

$$

SYNOPSIS...LFR
NEAR TERM...CAS
SHORT TERM...CAS
LONG TERM...ADM
AVIATION...ADM/CAS
MARINE...ADM/CAS
TIDES/COASTAL FLOODING...ADS
CLIMATE...LWX