-- Discussion containing changed information from previous version are highlighted. --
332
FXUS61 KAKQ 031910
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
310 PM EDT Fri May 3 2024

.SYNOPSIS...
A backdoor cold front pushes across the area today, leading to
much cooler conditions at the coast. Rain chances return thus
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 SATURDAY MORNING/...
As of 1030 AM EDT Friday...

Late morning sfc analysis shows high pressure remains SE of the
area, along and offshore the Carolina coast. Aloft, a ridge axis
is located just E of the area, extending into southern Quebec.
Well- advertised backdoor cold front has crossed into the FA,
with easterly winds and cool/moist maritime air noted along the
Atlantic coast of the Eastern Shore. Already seeing a wide range
in temps with 50s and 60s on the Eastern Shore and mid-upper
70s/around 80F further W. The backdoor front will continue its
journey SW today, creating non- diurnal temps that will have a
sharp gradient from NE to SW. Inland areas should be able to
warm into the mid-upper 80s (possibly ~90) by this aftn, with
falling temps as the front spreads further inland. Areas on the
Eastern Shore and Northern Neck will remain in the 50s and 60s.
Clouds will also increase through the day, becoming broken to
overcast by the afternoon. Winds turn to the NE behind the front
and become breezy, gusting to 20-25mph. There is a slight
chance for showers/thunderstorms in the Piedmont this afternoon
ahead of the advancing front (soundings show 1500-2000 J/kg of
CAPE w/ moisture pooling along the front), but CAMs generally
indicate isolated coverage. Have slightly expanded the 20% PoP
eastward towards RIC. Showers likely increase in coverage late
in the evening and overnight, but still look limited to the
piedmont and still scattered (40-50% PoPs). Lows
tonight/tomorrow morning will be a bit cooler than this morning,
dropping into the 50s.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
As of 400 AM EDT Friday...

Key Messages:

- Cooler temps and low clouds expected Saturday

- Intermittent precip expected Saturday and Sunday


The better moisture and lift moves in on Saturday and especially
Saturday night as the 850mb winds increase and have kept likely PoPs
over the NW 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. Still undercutting NBM highs a bit for Saturday.
Highs will range from the low 60s (or possibly even lower) in the NW
piedmont counties and the Eastern Shore, to around 80 across the far
south where some afternoon sunshine is possible. Increased coverage
in showers is expected Saturday night, but still keeping the likely
PoPs limited to W of I-95.

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
around 80, warmest SE VA/NC NC.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 400 AM EDT Friday...

Key Messages...

- Additional scattered showers and storms on 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.

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. Most will see temps in
the low 80s, upper 70s on the Eastern Shore.

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 5-7, 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 /19Z FRIDAY THROUGH WEDNESDAY/...
As of 215 PM Friday...

Degraded flight conditions are expected through most of the
03/18z TAF period as a backdoor cold front pushes further inland.
As of 18z, IFR CIGs (bases ~800 ft) have moved into ORF and
PHF. MVFR CIGs are noted at SBY, with VFR at RIC. Expect these
IFR CIGs to persist along the coast through the period.
Elsewhere, expect SBY and ECG to drop to IFR CIGs over the next
few hrs, with RIC holding off until this evening. CIGs may then
drop further to LIFR for a time tonight (best chances at ORF
and ECG). Additionally, there may be VSBY reductions below 3 SM
due to BR or FG. This part of the forecast is more uncertain so
have not gone lower than 3 SM in the TAFs at this time. In terms
of precipitation, most stay dry this aftn (a very brief shower
or storm cannot be ruled out at RIC), before more widespread
shower activity approaches the W later tonight into Saturday.
Areas of drizzle are also possible. Winds have turned to the E
behind the front at all TAF sites and E winds 10 should avg ~10
kt overnight into Saturday.

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

&&

.MARINE...
-- Changed Discussion --
As of 300 PM EDT Friday...

Key Messages:

- Small craft advisories are in effect for the Chesapeake Bay
  and lower James River. Advisories were expanded south to the
  NC/VA border and extended through this evening.

-Winds of 15 to 25 kt will persist this evening then diminish a
 bit late tonight/Sat morning, but winds may increase some
 Saturday and additional Small Craft Advisories may bee needed
 by Saturday/Saturday night.

Winds increased abruptly as expected earlier today behind the
backdoor cold front. Overall the NE winds have over-performed
with some gusts of 25 to 30 kt at times over the ocean and lower
Bay. SCA advisories are in effect for the Bay, lower James River
and coastal waters from the NC/VA border north. Winds will
persist into this evening, but should slowly decrease some by
midnight. That said given the pattern and gradient winds will
remain E-ENE at 15 kt gusts to 20 kt through the overnight.
Seas have increased to 4 to 6 ft from Cape Charles north and 3
to 4 near the NC/VA border. Given the easterly flow seas over
the ocean and waves at the mouth of the Bay may be slow to
decrease overnight.

Wind speeds increase again later Sat aftn/Sat night while
shifting to the SE and this reflected by nearly all of the
guidance. 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).Southerly flow looks as though it will
persist through most of next week with the next backdoor cold
front possible some time Friday.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
-- Changed Discussion --
As of 300 PM EDT Friday...

Have issues a Coastal Flood Statement for locations in the upper
Bay as tides increase and approach minor flood levels later on
Saturday. Tidal departures will increase overnight due to winds
persisting onshore from the E or ENE. Moderate levels are not
expected (except perhaps locally at Bishops Head), so no Coastal
Flood Watches are anticipated.
-- End Changed Discussion --

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory until 1 AM EDT Saturday for ANZ630>632-
     634-638.
     Small Craft Advisory until 7 PM EDT this evening for ANZ650-
     652-654-656.

&&

$$

SYNOPSIS...MRD
NEAR TERM...AM/SW
SHORT TERM...AM/MRD
LONG TERM...AM/MRD
AVIATION...SW
MARINE...LKB/SW/JAO
TIDES/COASTAL FLOODING...