239
FXUS61 KAKQ 032333
AFDAKQ

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

.SYNOPSIS...
A backdoor cold front pushes south and west of the area tonight.
On and off shower chances are expected Saturday and Sunday. Summerlike
conditions return to the area for next week with daily chances
of showers and storms.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 330 PM EDT Friday...

Key Messages:

- Dropping temperatures expected this afternoon behind a backdoor
cold front.

- On and off showers expected tonight through Saturday with the
highest coverage inland.

- Becoming dreary for all areas Saturday with extensive low-level
cloud cover.

Sfc obs, satellite, and radar data show the backdoor cold front
quickly marching W/SW across the area. Behind the front, temps are
falling quickly. It`s in the 50s on the VA/MD Eastern Shore and in
the 60s across Hampton Roads northwards to the Northern Neck. Ahead
of the front (over the Piedmont), temps have risen into the mid and
upper 80s. Thus, we are currently seeing a very impressive
temperature gradient over the area (55 at Ocean City/OXB vs 87 at
South Hill/AVC). Extensive low-level clouds are also slowly pushing
inland from the ocean and Chesapeake Bay. Expect the front to
continue advancing westward for the remainder of this afternoon. A
few CAMs show a few pop-up showers or storms developing along the
front given building instability (SPC mesoanalysis showing ~500-1000
J/kg across the Piedmont). Will continue a 20% PoP for these areas
through the afternoon. Additional shower chances are expected
overnight, with the highest coverage expected over the nrn half of
the area. Not expecting any thunder tonight. Some patchy fog may
also move onshore across SE VA and NE NC, but think visibilities
will not get too low given the elevated winds. Lows tonight will be
chillier than the previous few nights and around 50 on the MD
Eastern Shore to the mid-upper 50s for the rest of the area (lower
60s down along the Albemarle Sound).

The front will be well W/SW of the area by tonight into Saturday.
Sfc high pressure will be left in its wake across New England. This
will wedge a cool/moist low-level airmass over the entire area for
the day Saturday. This will also keep cloudy conditions in place.
The best forcing/lift and moisture remains across the W, so
expecting the highest coverage Saturday mainly W of I-95. Despite
this, it will tend to remain unpleasant even towards the coast w/
onshore flow and patchy drizzle. Continue to trend highs lower with
temps struggling to reach 60 across the N, with mid 60s-low 70s
elsewhere. There is a chance that far SW portions of the CWA (e.g.,
Northampton/Bertie Counties in NC) reach the upper 70s, but this may
even be overdone. These values are still below NBM (especially S).
On and off "showery" rainfall continues overnight Saturday with lows
in the 50s N to 60s S. QPF through tomorrow averages from up to
0.50" across the W, 0.1-0.4" central, and 0.00" to a few hundredths
of an inch closer to the coast.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 330 PM EDT Friday...

Key Messages:

- Continued unsettled, but warmer, Sunday.

- More humid on Monday with showers and storms areawide.

The front is expected to lift back N Sunday into Monday, shifting
the low-level flow to the S. These factors should act to scour out
the dreary conditions seen on Saturday. However, still expecting
shower redevelopment in the aftn hours as temps warm into the 70s
and 80s and the residual front and a weak disturbance aloft remains
near the area. An early look at some CAMs show that they are not
particularly enthusiastic at widespread rainfall coverage, which
makes sense given a lack of any focused areas of lift. Lows Sun
night in the 60s.

Upper heights begin building back N for Monday with high temps
warming into the low 80s areawide. Despite the warmer temps, a lee
trough is expected to develop in the aftn and evening hours.
Combined w/ an approaching shortwave from the OH River Valley,
showers and storms are expected to develop over the higher terrain
in the afternoon and slide eastward into the evening. Models show
around 1000 J/kg of CAPE developing with rather weak shear.
Therefore, the severe threat looks relatively low, but cannot rule
out a stronger storm or two. Soundings do show a rather saturated
atmospheric column (PWATS potentially reach or exceed 1.5"), which
could lead to some heavier downpours. Dew points also increase into
the mid-upper 60s so the humidity will make it feel more like early
summer. Shower/storm activity diminishes inland after midnight, but
may linger closer to the coast overnight. Lows remain mild in the
mid 60s.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 335 PM EDT Friday...

Key Messages...

- 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 to end of next week.

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 shortwaves (likely of mesoscale
origin from convection over the Ohio Valley and central plains)
moving through the area. These convective complexes may also move
through the region from the NW, but these features are
notoriously hard to predict. Although we are talking about days
5-7, the relatively strong upper flow combined with relative
steep mid level lapse rates of up to 7-7.5 C/km would suggest
the possibility of severe weather. Instability will certainly
not be a limiting factor as temps warm into the 80s and 90s
every day. At this time, the synoptic pattern for severe looks
most favorable Thursday with an approaching trough and the most
robust CAPE. The CSU Machine Learning Probabilities have picked
up on the aforementioned parameter space and suggest at least a
slight risk for severe weather on Wednesday and Thursday for
the entire area and Friday for southern/southeast areas. We
continue to have plenty of time to monitor this, but the area
may become more active by the end of next week.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 730 PM EDT Friday...

Degraded flight conditions are expected to continue through the
00z/04 TAF period as MVFR to LIFR CIGs have already overspread
the terminals in the wake of a backdoor cold front (with E-NE
winds of 10-15 kt with gusts to 20 kt). IFR/LIFR CIGs are
expected through much of the night with some improvement on Sat
(to 1000-2000 ft) with continued onshore flow. In terms of
precipitation, mainly dry wx is expected through 03z before
more widespread shower activity approaches the W later tonight
into Saturday. Cannot completely rule out thunder at RIC
overnight, but the chance of this is very low. Areas of drizzle
are also possible through Sat AM. Shower chances continue on
Saturday (highest PoPs at RIC w/ lesser chances near the coast).

Outlook...Sub-VFR conditions expected at times through the
weekend and even into Monday due to an unsettled weather
pattern. Scattered showers and tstms are expected on both Sunday
and Monday. A warmer, more summerlike pattern returns by
Tuesday with chances for storms each afternoon/evening.

&&

.MARINE...
As of 710 PM EDT Friday...

Key Messages:

- Small Craft Advisories have been extended for the Chesapeake
  Bay and lower James River through Saturday night.

- Small Craft Advisories for the seas north of the
  Virginia/North Carolina border have been extended until 1 AM
  Saturday.

- Winds of 15 to 20 kt with gusts to 25 kt will diminish a bit
  later tonight into Saturday morning before increasing
  Saturday.

Winds behind the backdoor cold front remain 15-20 kt with gusts
to 25 kt this evening (lower across the NC coastal waters).
Winds diminish some overnight but should still gust to 20 kt
through the night. Winds ramp back up Sat afternoon into Sat
night with gusts to 25 kt. Winds become ESE late Sat night as
a warm front lifts N. Waves remain 2-4 ft during this time.
Given the gusts to 20 kt between the two surges, have opted to
extend SCAs through Sat night to account for both surges for
the Ches Bay and Lower James. Additionally, with seas of 4-6 ft
this evening N of the VA/NC border and persistent E flow, seas
should be slow to subside to 4 ft tonight. As such, have
extended SCAs for all coastal waters N of the VA/NC border until
1 AM Sat.

The front lifts back N on Sunday, shifting winds to the SE/SSE.
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.

&&

.TIDES/COASTAL FLOODING...
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.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory until 7 AM EDT Sunday for ANZ630>632-634.
     Small Craft Advisory until 4 AM EDT Sunday for ANZ638.
     Small Craft Advisory until 1 AM EDT Saturday for ANZ650-652-
     654-656.

&&

$$

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