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fxus61 kakq 231725 
afdakq

Area forecast discussion
National Weather Service Wakefield Virginia
125 PM EDT sun Apr 23 2017

Synopsis...
a frontal boundary becomes nearly stationary across the Carolinas
today. A strong low pressure system will cross the region
through midweek...and bring periods of moderate to heavy
rainfall to the region Monday and Tuesday.

&&

Near term /through tonight/...
pcpn moving more east than northeast as it advances from the SW.
Still some breaks in overcast / thinning across the north due to the high
moving east across PA. Think the pcpn eventually wins out as
afternoon progresses so adjusted grids a bit. Main change was to
change from a convective pcpn form to more stratiformed since
we are on the cool side of the developing low (i.E. Rain vs shwrs).
Remaining cool with highs 55-60.

Pvs dscn:
late morning msas has low pressure over nrn Georgia with the cold
front extending east to near ilm then offshore. Akq fa wedged in
as high pressure to the north provides a cool NE wind. Rain
associated with the first wave has diminished to some light rain
over the south, even some breaks in overcast across the north. However,
moisture from the second wave already making a Beeline for the
region from the SW. Thus, expect a cloudy, cool and increasingly
wet afternoon ahead as this moisture overspreads the region.
Exception will be across the lwr Maryland Eastern Shore where any rain
will not arrive until late. Highs 55-60, coolest over the
Piedmont due to the developing in- situ wedge. Thunder chcs just
about none due to the cool and rather stable airmass.

&&

Short term /Monday through Tuesday night/...
a cloudy and wet period to begin the work week. Periods of MDT
to hvy rainfall expected Monday night and Tuesday. Quantitative precipitation forecast btwn 1.5
to 3.5 inches (highest across the southern third of the area).

Models in general agreement that aforementioned upr-level low
cuts off as it tracks southeast across the southeast and the coastal
Carolinas. System then takes on a neg tilt Mon night that
spawns a coastal low off the se coast Monday. Resultant strong
coastal front will be conducive for heavy rainfall across the
southeast conus, which will eventually move in our direction
late Monday night and Tuesday.

Look for mainly cloudy skies with periods of MDT to locally hvy
rainfall Mon/Tue as copious amounts of deep Atlantic moisture
gets entrained north and rotates around the system. Thus,
confidence remains high enough to go with likely to categorical
pops each period. Kept high pops but low chc thunder along the
coast.

Highs Mon in the mid 50s-mid 60s except 65-70 sern coastal
areas. Lows Mon nite in the upr 40s-lwr 60s. Highs Tue in the
lwr 60s-lwr 70s.

Hydro wise, no flood headlines anticipated attm with numerous breaks
in between bouts of rain expected. Do expect some healthy rises in
local river by early next week, especially if the heavy rainfall
falls over the headwaters. Given the forecasted quantitative precipitation forecast and after coord
with the rfc, expect minor flooding at Lawrenceville on the Meherrin
River by Tue. Again, this based on quantitative precipitation forecast so plenty of time to adjust
if needed.

Rain tapers off from south to north Tuesday night as the upper
low pivots offshore and NE of the Delmarva overnight into
Wednesday morning. Early morning lows 55-60.

&&

Long term /Wednesday through Saturday/...
long term period will feature a trend towards drier and warmer
conditions. For Tue night, mid-level cutoff low and associated
sfc low start to progress offshore, with some pcpn psbl on the
backside of the systm. Pops range from 20-40%. Warming trend
then commences for Wed as deep swly flow develops across the
eastern Seaboard, lasting through the end of the week with temps
in the 70s Wed reaching the 80s most areas Thu and Fri.

&&

Aviation /18z Sunday through Thursday/...
high pressure moving east across PA is keeping ric/sby VFR attm
but mfvr conditions across the south with -ra movg east. Expect
MVFR St to become dominate cloud coverage across the entire area
as the slug of rain overspreads the region. Sby will be the last
to go MVFR probably closer to 00z. After that expect widespread
MVFR/IFR ceilings in areas of rain/fog for the rest of the forecast
period as the system is slow to develop off the se coast. Gusty
NE winds (15-25 kts at times) along coastal taf sites.

Outlook...a well organized low will linger just off the mid
Atlantic coast through mid week before lifting NE and away from
the area. Expect a continuation of MVFR and IFR conditions along
with areas of rain/fog through tues, slowly ending west to east
tues night. MVFR/VFR expected later in the week as high pressure
moves in.

&&

Marine...
northeast flow prevails over the marine area, between high pressure
building into the northeast and low pressure over the southeast.
Speeds are generally 15-20 knots, with marginal Small Craft Advisory conditions in
the Bay. Waves generally 2-3 feet and seas 3-6 feet (highest
southern coastal waters). High pressure builds in from the northwest
today as low pressure remains over the southeast. Gradient winds
relax later this morning into the afternoon, resulting in a brief
lull in Small Craft Advisory conditions. Longer reprieve expected in the Upper Bay,
so have opted to drop the headlines mid morning. In the southern
Bay, marginal Small Craft Advisory conditions expected today with occasional gusts to
20-23 knots. Gusts of 20-25 knots also expected in the sound and
southern coastal waters today. Seas average 4-6 feet. High pressure
slides offshore tonight as low pressure slides toward the southeast
coast. The result will be an uptick in northeast winds tonight, with
speeds of 15-25 knots. Gusts up to 30 knots in the coastal waters.
Seas increase to 5-8 feet. Am concerned guidance is not handling the
northeast flow and long period swell the best, so have opted to go
above guidance on wave heights. There is the potential for high surf
conditions as well, but there remains some uncertainty so have held
off on high surf headlines. Small Craft Advisory headlines return for the rivers late
tonight. Low pressure slides off the southeast coast Monday and
deepens. Strongest gradient winds begin to expand northward Monday,
with speeds of 15-25 knots expected from the mouth of the Bay
northward. A brief lull is possible for the sound Monday. Seas
remain 5-8 feet, but subside to 4-6 feet in the southern coastal
waters. Waves 3-6 feet (highest in the mouth of the bay).

Low pressure slowly lifts along the southeast coast Tuesday and
offshore the mid-Atlantic coast Tuesday night. Onshore flow and Small Craft Advisory
conditions persist. Seas build upwards of 6-9 feet Tuesday. Flow
becomes northerly Tuesday night as speeds diminish at or below 15
knots as the low lifts over the waters. Seas subside to 4-6 feet
late Tuesday night. Waves 1-2 feet. The low weakens and lifts away
from the region Wednesday as sub-Small Craft Advisory conditions return. Seas
forecast to drop below 5 feet late Wednesday. The next front
approaches the waters Friday.

&&

Tides/coastal flooding...
tidal departures are averaging 1 to 1.5 feet early this morning
thanks to persistent onshore flow. Tidal departures will build
today through midweek as onshore flow prevails ahead of an
approaching area of low pressure. Majority of the tidal
locations in the Bay and Atlantic coast will reach action stage
today and tonight, but no minor flooding is anticipated at this
time. However, tidal departures increase to 1.5 to 2 feet
Monday. Minor coastal flooding is expected during high tide
Monday night and again on Tuesday, especially in the lower
Chesapeake Bay and Atlantic waters. Depending on the exact track
of the low, high end minor to low end moderate coastal flooding
is possible Tuesday night. Departures subside Wednesday as low
pressure lifts along the northeast coast and flow becomes
offshore.

&&

Akq watches/warnings/advisories...
Maryland...none.
NC...none.
Virginia...none.
Marine...Small Craft Advisory from midnight tonight to midnight EDT
Monday night for anz635>637.
Small Craft Advisory until 6 am EDT Tuesday for anz632-634-650-
652-654-656-658.
Small Craft Advisory until 6 am EDT Monday for anz633.
Small Craft Advisory from 6 PM this evening to 6 am EDT
Tuesday for anz630-631.
Small Craft Advisory from 6 PM this evening to midnight EDT
Monday night for anz638.

&&

$$
Synopsis...mam
near term...mpr/mam
short term...mpr/mam

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