544
FXUS61 KAKQ 031815
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
215 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 /THROUGH TONIGHT/...
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 /SATURDAY 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 THURSDAY/...
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 /18Z 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...
As of 300 AM EDT Friday...

Key Messages:

- Small craft advisories are in effect for the Chesapeake Bay
  and lower James River, and for the Ocean N of Parramore Island
  for 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 N/1-2 ft S, with
waves in the Bay and rivers 1-2 ft (or less). The wind has
shifted to the NNE at buoy 44009 and into the Ocean zone from
the MD/DE border south towards Chincoteague. There may be a few
hrs worth of marine fog toward sunrise in these northern
Atlantic coastal waters before the winds increase, but do not
anticipate this being enough for a Marine Dense Fog.

Otherwise, 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, but will likely over- perform at
least across the northern coastal waters so have added the Ocean
zones N of Parramore to a Small Craft Advisory through 4pm this
aftn (with winds ~20kt gusting to 25 to near 30 kt), and seas
of 4-5 ft. 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. In the
Bay/James, SCA headlines remain in effect from later this
morning/aftn through 1 AM Sat morning. On the ocean S of
Parramore, wind gusts and wave heights on average should stay
below 25 kt with seas building to ~4ft. 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, will keep these zones out of any headlines. 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 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
TIDES/COASTAL FLOODING...