521
FXUS61 KAKQ 030540
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
140 AM EDT Fri May 3 2024

.SYNOPSIS...
A backdoor cold front pushes into the Maryland eastern shore
late tonight, then inland across the remainder of the area on
Friday, leading to much cooler conditions at the coast. Rain
chances return Friday evening through Sunday as a series of
disturbances impact the region. Summerlike conditions return
to the area by the middle of next week.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
As of 905 PM EDT Thursday...

Latest analysis reveals sfc ridge offshore of the coastal
Carolinas early this evening. Meanwhile to the north, 1024+mb
sfc high pressure is building south from Ontario and Quebec into
the northeastern US. This feature is also driving weakening low
pressure over eastern New England south and offshore of the
northeast coast. Aloft, anomalously strong mid/upper level
ridging which allowed for highs in the upper 80s to low 90s
inland today remains in place this evening from the mid-south
to the southeast coast, extending north across the mid-
Atlantic region.

Mainly quiet weather prevails through the night, with high
pressure in place just offshore. Guidance suggests that the
surface low to the north dives farther south overnight, with the
associated cold front diving across the MD eastern shore after
10z/6am late tonight into Friday morning. Expect winds to back
to the NE post-frontal, with an increase in clouds over the
Delmarva for the afternoon, reaching eastern VA by mid to late
afternoon. This evening`s guidance is a bit too aggressive right
now given latest regional observations, and do not think fog
will be an issue tonight given that we had a day of full
sunshine today to mix out much of the remnant moisture from
yesterday`s light rain. That said, some spotty ground fog will
be possible, with the best chances mainly east of US-13 on the
Atlantic coast of the eastern shore. Mild early morning lows
will be in the mid- upper 50s across the MD eastern shore and
lower 60s elsewhere.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
As of 905 PM EDT Thursday...

Key Messages:

- Increasing clouds from NE to SW Friday into Friday night as a
  cold front drops across the region.

- Rain chances increase mainly west of the bay tomorrow
  afternoon into tomorrow evening. Lighter, intermittent
  rainfall possible along the coast tomorrow night and into
  Saturday.

The backdoor front will continue to move SW across the region on
Friday. Models have good timing on the front, reaching the VA
eastern shore and SE VA Friday morning, the RIC metro around lunch
time, then to the southern Piedmont of VA by late afternoon.
Latest CAMs show some pop up showers for areas mainly west of
I-95 as the front moves SW. Have therefore included slight
chance PoPs for the afternoon in that same general region. Could
not completely rule out thunder as the HREF mean SBCAPE shows
500-1000 J/KG. There will be quite a gradient of temperatures
across the area, with Ocean City likely staying in the 50s
through the day, while areas in the southern Virginia Piedmont
will reach upper 80s for highs. The temperature will likely
remain steady or even fall slightly once the front passes your
location tomorrow.

Improved moisture return sets up for Friday night and continues into
Saturday. Best moisture stays mainly over the Piedmont, and will
also be helped by overrunning over top the low level wedge. The
better moisture and lift moves in on Saturday as the 850mb winds
increase and have kept likely PoPs over the Piedmont, tapering to
low chance at the coast. Even at the coast though, it will not be
terribly pleasant in the morning with onshore flow, low clouds
and the potential for drizzle into Saturday morning. Have
generally undercut the NBM highs for Saturday, especially
across the far NW. Highs will range from the mid 60s (or
possibly even lower) in the NW piedmont counties, to lower 80s
across the far south where some afternoon sunshine is possible.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 905 PM EDT Thursday...

Key Messages...

- Additional scattered showers and storms on Sunday and Monday.

- A more summer-like pattern with warmer days and chances for
  late afternoon and evening showers and storms appears to be on
  the way for the middle of next week.

The backdoor front will attempt to move back north on Sunday as the
Ohio valley system approaches from the west. Showers may be more
widespread on Sunday due to a weak disturbance aloft lowering
heights across the region. Best moisture and still expected
along/west of I-95.  As such, have continued with likely/categorical
PoPs over the west on Sunday, tapering to chance PoPs at the coast.
Highs expected to be warmer than Saturday in the mid 70s to lower
80s, warmest SE VA/NC NC.

By Monday, the warm front will be well north of the area. However,
the system over the Ohio Valley will be moving through during the
day. Expect another round of showers/storms mainly during Monday
afternoon into Monday evening as a stronger upper disturbance moves
through in the W-NW flow aloft. Slightly more instability on Monday
vs Sunday so more thunderstorms are expected.

We get into an almost summertime pattern by Tuesday as the ridge
aloft builds overhead with afternoon/evening showers and
thunderstorms each day being triggered by the lee side trough. The
GFS and ECMWF both suggest the ridge breaks down slightly by Wed/Thu
with stronger 500mb flow of up to 50 kt by Wed afternoon. Along with
this, those models suggest weak short waves (likely of mesoscale
origin from convection over the Ohio Valley and central plains)
moving through the area. Although we are talking about days 6 and 7,
the relatively strong upper flow combined with relative steep mid
level lapse rates of up to 7 C/km would suggest the possibility of
severe weather. In fact, the CSU Machine Learning Probabilities
suggest a slight risk for severe weather on Wednesday and again on
Thursday. We have plenty of time to monitor this, but the area may
become a little more active by the end of next week.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
As of 905 PM Thursday...

VFR conditions with light winds to begin the 00z TAF period,
with VFR conditions to prevail through the night. A backdoor
cold front dives southwest across the Maryland Eastern Shore
towards sunrise Friday morning, allowing winds to turn NE by
Fri morning, with MVFR conditions on the eastern shore tomorrow,
especially east of KSBY to KOXB. The front will continue to
slowly move SW on Friday, perhaps reaching the other terminals
by 18-20z. Some scattered showers and perhaps even a
thunderstorm will be possible at KRIC and points west tomorrow
afternoon into tomorrow evening.

Outlook...Sub-VFR conditions expected at times through through
the weekend and even into early next week due to an unsettled
weather pattern through Monday. A series of systems will cross
the region, with chances for rain/storms each day. A warmer,
more summerlike pattern returns by Tuesday with chances for
storms each afternoon/evening.

&&

.MARINE...
As of 130 AM EDT Friday...

Key Messages:

- Small craft advisories remain in effect for the Chesapeake Bay
  and lower James River for later today behind a backdoor cold
  front.

-Winds diminish a bit late tonight/Sat morning, but additional
 Small Craft Advisories may bee needed by lat Saturday/Saturday
 night.


Still rather quiet across the waters early this morning with SSW
winds of 10-15 kt or less and seas 2-3 ft with waves in the Bay
and rivers 1-2 ft (or less). Guidance suggests another bout of
marine fog will be possible toward sunrise, mainly across our
northern Atlantic coastal waters behind the backdoor frontal
passage. E/NE winds increase abruptly later this morning as
cool/dry advection gets going behind the front with pressure
rises on the order of 4-5mb/6 hr. E-NE winds increase to 15-20
kt with gusts to around 25 kt. The highest confidence in meeting
small craft criteria is in the southern bay/lower James, but
the entirety of the bay should at least see marginal SCA
conditions. SCA headlines remain in effect for these areas from
later this morning/aftn through 1 AM Sat morning. On the ocean,
wind gusts and wave heights on average should stay below 25 kt
and 5 ft, respectively. Should note that onshore flow conditions
tend to elevate seas a bit higher than guidance, so will
monitor the trends later this morning As of now, seas are
forecast to increase to ~4 ft. The best chance of 5 ft seas
would be N of Cape Charles. Easterly winds subside some by Sat
morning, but will remain around ~15 kt. Wind speeds tick up
again later Sat aftn/Sat night while shifting to the SE. This
brings another chance at SCA conditions, again mainly over the
Bay. Seas remain 3-4 ft with waves 2-3 ft in the
bay/rivers/sound.

The front lifts back N on Sunday, shifting winds to the S. SSW
winds return for Monday through the middle of next week (but
likely remain sub-SCA).

&&

.TIDES/COASTAL FLOODING...
As of 130 AM EDT Friday...

Tidal departures increase later today in response to the winds
turning onshore from the E or ENE. May consider a statement for
the lower Bay/lower James and for the upper Bay across the
northern Neck and perhaps Dorchester MD for the tide cycle this
evening/tonight depending on how the water levels respond.
Additional tidal flooding, mainly to minor flood thresholds
appears likely by later Sat through Sunday across the upper Bay
as winds become more SE to S. Moderate levels are not expected
(except perhaps locally at Bishops Head), so no Coastal Flood
Watches are anticipated.


&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory from 10 AM this morning to 1 AM EDT
     Saturday for ANZ630-631.
     Small Craft Advisory from 1 PM this afternoon to 1 AM EDT
     Saturday for ANZ632-634-638.

&&

$$

SYNOPSIS...MRD
NEAR TERM...MAM/MRD
SHORT TERM...MRD
LONG TERM...MRD
AVIATION...AJB/MAM/MRD
MARINE...LKB/SW
TIDES/COASTAL FLOODING...