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591
FXUS61 KAKQ 121937
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
337 PM EDT Sun May 12 2024

.SYNOPSIS...
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Scattered showers are possible for the Eastern Shore this
afternoon as an upper trough exits the region. Dry and warmer
to start the work week before another round of showers and
storms returns to the region Tuesday and Wednesday.
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&&

.NEAR TERM /THROUGH MONDAY/...
As of 330 PM EDT Sunday...

Key Messages:

- Showers and a few storms are possible across the eastern shore
  this afternoon.

- Drying out tonight with some patchy fog possible on the
  eastern shore.

- Warmer and remaining dry for Monday.

Latest analysis reveals several weak lows from NE PA to just off
the Delmarva along a weakening and increasingly diffuse frontal
boundary draped across the Atlantic coast of the Maryland
eastern shore into eastern PA. Out ahead of this boundary, weak
1014mb high pressure remains along the northeast coast. Aloft,
an upper trough lingers over New England. Cooler temps and
steeper mid level lapse rates ahead of the crossing upper trough
have allowed showers and some isolated to scattered storms to
re- fire over the MD Eastern Shore this afternoon. As of this
writing, the stronger, albeit sub-severe low-topped convection
has pushed offshore. However, some additional weak overrunning
moisture will allow for scattered showers to continue over the
next 90 minutes to 2 hours before tapering off into the evening
hours.

Farther south, subsidence behind the passing trough and high
pressure building to the SSW has allowed for plenty of sunshine
over the SW 2/3 of the area this afternoon. Temps range from the
low to mid 70s across central and south central VA into NE NC,
with highs in the mid-upper 70s over inland areas far south
still looking good. Much cooler upper 50s to low 60s over the
eastern shore with showers and onshore flow, with mid 60s to
around 70 along the immediate coast down to Currituck Beach NC.

Drying out tonight with a clearing sky along the MD coast
behind the departing trough. Some patchy fog will again be
possible late, this time on the eastern shore and perhaps also
over the VA northern neck, though forecast confidence is a bit
lower over southern sections with more time to clear out this
afternoon. Early morning low temps fall into the mid to upper
40s inland, upper 40s to low 50s along the coast.

High pressure over the coastal plain slides offshore on Monday,
bringing warmer temperatures and dry conditions (briefly) back
to the region. High temps climb back into the 70s to low 80s.
Clouds start to increase by late in the afternoon from the SW
ahead of our next system.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 330 PM EDT Sunday...

Key Messages:

- Increasing clouds Monday night, with showers developing late
  over inland areas.

- Next system moves in Tuesday with showers and thunderstorms.
  Widespread severe weather is not expected.

- Showers and a few storms linger on Wednesday before moving
  offshore overnight.

Rain chances quickly ramp up after midnight Monday night/early
Tuesday and into the day on Tuesday. A closed upper low over the
mid-Missouri Valley translates east into the Western TN Valley
Monday night, with the system slowing and lingering across the
TN Valley through midweek.

Overrunning moisture pushes into the piedmont region west of
RIC in the early morning hours Tuesday, reaching the I-95
corridor by midday, and the coast by mid- afternoon.
Kinematics and relatively weak deep- layer shear would indicate
only a modest chance for storms on Tuesday, with the overall
severe threat even lower. However, will maintain a thunder
chance through the afternoon on Tuesday over SW sections and
along the SE coast into later Tuesday evening. QPF through Tue
night between 3/4" and 1" of additional rainfall, with locally
higher totals possible. Best chances for periods of locally
heavy rainfall will be across south central and southeast VA
into northeast NC Tue night, where secondary low pressure looks
to develop Tuesday aftn, lifting a warm front across the region
Tuesday evening. Better area of IVT and PW values AOA 1.5-1.75"
(near climo daily maxes) then look to stream NNE across our SE
coastal plain Tuesday evening, with showers and storms forecast.
For its part the CSU machine learning probs do show a marginal
risk area for its ERO forecast, which has been matched by WPC
for day 3 (Tuesday).

Rain briefly tapers off early Wednesday morning, especially
across the S/SE, as mid-levels briefly dry out. However, we
never really dry out lower levels through this period. This
likely portends continued overcast/substantial cloud cover and
light rain throughout Wednesday, as the closed low to the west
opens up and the surface reflection weakens as it crosses the
central/southern Appalachians. Precipitation character remains
a bit more stratiform through the day for most. However, chances
for storms do increase a bit over NE NC and perhaps into Hampton
Roads by afternoon as the weakening upper low approaches. This
allows for a period of increased deep-layer shear (25-35 kt)
along with some decent instability (LREF does show 500-750 J/kg
of CAPE by afternoon) in the pseudo warm sector across the SE.

As high pressure builds to the north, the weakening surface low
crosses the area Wed night, with the positively-tilted upper
trough lingering over the area into Thursday. Given this timing,
Wednesday night would then feature diminishing rain chances and
drier air filtering into the region. Kept highs in the 70s for
much of the area on Wednesday, with some lower 80s across the SE
coast. Lows Wed night in the 50s to near 60.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 330 PM EDT Sunday...

Key Messages:

-Continued warm late this week with increasing chances for showers
 and storms later Friday and Saturday.

High pressure builds in briefly on Thursday but another system
approaches on Friday with another chance for scattered showers
and storms, though the 12z suite of models is notably slower
with returning moisture back into the local area, and have
accordingly pushed PoPs a bit lower with this forecast package.
High temps remain in the 70s to low 80s on Thursday and Friday
with low to mid 80s on Saturday. Overnight lows continue around
60 degrees.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
As of 200 PM EDT Sunday...

VFR conditions across area terminals to begin the 18z TAF period
persist through tonight for most areas. Exception will be along
the MD coast in the vicinity of the KSBY terminal. Here, expect
additional showers and storms will move across the eastern
shore including KSBY into late afternoon as weakening front and
the parent upper trough axis slide through the region. Breezy
NNW winds ~ 10 kt with gusts 15-20 kt this afternoon,
diminishing by 00z. Clearing skies and VFR conditions are
expected overnight with winds remaining light and variable.
Areas of fog and potentially some low stratus will be possible
once again late tonight, with best chances of Sub-VFR CIGs
occurring around KSBY after 06-08z. NBM is trending toward some
low-end probabilities for some sub-VFR CIGs at PHF, but forecast
confidence is much lower there, and have accordingly held out of
the TAF for now.

Outlook: Dry conditions return area-wide on Monday. However,
unsettled weather returns Tue-Wed as another low pressure
system approaches the FA.

&&

.MARINE...
As of 330 PM EDT Sunday...

Key messages:

-Sub-SCA conditions expected through Monday.

-Additional SCAs possible ahead of a low pressure system Monday
night and more likely Tuesday into Wednesday morning

A boundary was draped across the MD Eastern Shore and a weak area of
low pressure was just offshore as of afternoon sfc analysis, leading
to slight variation in wind direction across local waters today.
Latest obs reflect northerly winds in the bay and rivers at 10-15kt,
while winds over coastal waters are more northeasterly at ~10kt.
Latest buoy obs show seas of 3-4ft and waves 2-3ft. As the boundary
moves away from the local area, high pressure will build behind it
before sliding offshore tomorrow. Overnight, onshore winds will be 5-
10kt. Winds then increase out of the S-SE on Monday as that high
moves well offshore. In fact, a brief period of low-end SCA
conditions is possible Monday night, and local wind probs are now
showing a 50-75% chc of sustained 18kt winds on the Ches Bay between
7 PM Mon-1 AM Tue. However, will hold off on issuing SCAs for now
given marginal and relatively brief nature of it.

S winds briefly diminish to 10-15kt Tuesday AM. However, a low
pressure system will approach the area on Tuesday before crossing
the area from west to east late Tuesday night/early Wednesday. The
pressure gradient will increase ahead of the system by Tue
aftn/evening, allowing S winds to increase to 20-25kt (and remain
elevated through most of Tue night). Local wind probs show an 80-
100% chc of 18kt winds on the bay Tue night. Probs of sustained 25kt
winds are at 20-45% (highest in southern coastal waters). In
addition, seas build to 5ft ahead of the mid-week system. Sub-SCA
conditions are expected behind the system Wed night-Thursday (w/ N
winds near 15kt and seas subsiding to ~4ft). Waves on the bay will
be 1-3ft through most of the period (although 4ft waves are possible
Tue night).

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...None.

&&

$$

SYNOPSIS...MAM/RHR
NEAR TERM...MAM
SHORT TERM...MAM
LONG TERM...MAM/RHR
AVIATION...MAM/RHR
MARINE...AM/ERI