Area Forecast Discussion
Issued by NWS Wakefield, VA-- Remove Highlighting --
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FXUS61 KAKQ 221922
Area Forecast Discussion
National Weather Service Wakefield VA
322 PM EDT SUN MAY 22 2016
A trough of low pressure will linger over the Mid Atlantic through
Monday. This trough will gradually move offshore Monday night into
Tuesday. An upper level ridge will build in from the west by the
middle of the week.
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Latest upper level analysis features a very familiar omega
blocking pattern, characterized by upper level ridging from the
Red River Valley into the Western Great Lakes and persistent upper
level troughing over the Mid-Atlantic/Northeast and the Northern
Plains into the Canadian Prairies. At the Surface, sfc low
pressure continues to lift offshore of the VA/NC coast this
afternoon. Regional radar mosaic showing areas of light rain or
drizzle pushing across the area as the upper trough slowly digs se
into the local area.
Mostly cloudy to overcast conditions are bringing another cool
day today w/high temperatures in the 50s to low 60s north...mid
60s south...this represents maxima that are -1.5 to -2 st dev.
Pops remain highest across northern portions of the area over the
next few hours. Have upped pops into categorical range for
periods of rain through early evening, coincident w/ribbon of low
level convergence/weak lift over the VA Northern Neck and Lower MD
Eastern Shore this afternoon. Radar has also begun to fill in out
in the E VA Piedmont, along another subtle convergence boundary.
CAMs continue to show this activity dropping south into NC by
early evening. Given this, and that areal coverage with this
activity is a bit lower, decided to maintain chc wording here
through the early evening.
The upper trough closes off tonight as it settles over SE VA
and Eastern NC tonight into Monday morning, with h5 heights
remaining on the order of ~-2 st dev. Mostly cloudy to overcast
conditions continue overnight. Likely pops (rain/drizzle) edge s
along and south-southeast of I-95 and I-64 tonight as the best
area of lift gradually pinwheels southeast over the area
overnight into Monday morning from central/e-central VA south
into southeast VA. Continued mostly cloudy to overcast with early
morning lows Monday mainly in the low/mid 50s.
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Upper level low will continue to slowly wobble off of the mid-
atlantic coast through the day, eventually sliding offshore by
monday night. This will produce more in the way of sct to numerous
showers on Monday, mainly in the afternoon and evening. Showalter
index numbers/LI values remain modestly/minimally unstable.
Nevertheless, have maintained a slight chc for thunder inland as
the upper cold pool pushes across. Temps once again a touch below
normal. Look for Monday maxima to top out in the upper 60s/around
70 inland, with lower to middle 60s along the southeast coast and
immediate coastal locations.
Evening stabilization should allow for partial clearing inland,
with any areas of showers to diminish quickly after sunset into
Monday night, though pops linger a bit later into the night over
the Eastern Shore. Pops drop off even further after midnight as
the upper low continues to push farther off toward the New
England coast into Tuesday morning. Remaining mild with early
morning lows Tuesday morning in the lower-middle 50s, under a
partly to mostly cloudy sky.
The Tuesday/Wednesday time frame will be characterized by
gradually improving conditions across the region behind the
departing upper low, as high pressure at the surface and aloft
slowly builds across the region in its wake for the mid week
period and beyond. While a gradually clearing sky/dry wx is
anticipated inland (actually mostly sunny by afternoon in the
piedmont), mostly cloudy conditions and some slight to low end
chance pops continue along eastern third of the area. This is in
association with one last upper disturbance rotating through
behind the upper trough. Again, while surface-based instability
looks to be minimal, Showalter numbers indicate some modest,
mainly elevated, instability. Will therefore continue with thunder
mention. Warmer on tuesday with highs in the upper 60s to around
70 coastal locations, low to mid 70s along the coast and mid 70s
to near 80 degrees inland.
Moderating/warming temperatures continues on Wednesday, as 1024+mb
surface high pressure slides offshore, as upper ridging build east.
Deep layered W-SW flow will bring increasing temps and moisture
across the region, though with PW values on the order of 0.50 to
0.75", and with models continuing to trend down with modeled rain
chances, will keep pops out for Wednesday. For the first time in a
couple of weeks, temps trend back up above climo area-wide on
Wednesday, with forecast maxima in the upper 70s to low 80s over
coastal sections along the Eastern Shore, low to mid 80s
southeast VA/NE NC coast, and mid to upper 80s inland.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
-- Changed Discussion --Bermuda sfc high pressure resides over the wrn Atlantic Ocean
through the long term periods as upper level ridging moves
over the ne CONUS during this time. Although the ridge becomes
more pronounced Fri through Sun, weak waves of energy/moisture
are expected to stream across the wrn fringes of the ridge.
QPF is being depicted each aftn/evening through Sat, however
this appears to be overdone given lack of preferred dynamics
and lack of definitive upper level features to aid lift for
convective development to occur. Held onto slight chance POPs
in far nw counties Thu aftn/evening and then slowly migrate
them ewd Fri/Sat. Current thinking is that the end result will
be high clouds streaming through the region rather than light
rain showers with isolated thunder. Meanwhile, low pressure
begins to develop over the Caribbean on Fri and is expected to
drift twd a location off the FL/GA coast by Sun. Will maintain
slight chance POPs for Sun/Sun night across Central VA due to
pop-up showers developing on the mtns and also in ne NC since
wraparound moisture could make it into this area during this
Overall, high temps should run around 5-7 degrees above normal
Thu-Sat. Highs generally in the mid 80s (mid 70s-low 80s
beaches). Low temps also running about 5 degrees above normal
Thu-Sat nights. Cooler Sun in anticipation of more clouds with
highs in the lower 80s inland and in the mid-upper 70s beaches.
-- End Changed Discussion --
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --A moist and unsettled pattern will persist thru Monday, as an upr
low drops southward into/over the fcst area. This feature will
maintain MVFR/IFR conditions across the region. Most TAF sites
have become MVFR as of 17Z, and expect MVFR to dominate through
00Z. Exception will be KSBY, where IFR will prevail. Scattered
showers becoming more widespread during the last hour, and these
will affect all terminals but KECG, which looks to remain dry
through much of the 18Z TAF period. Latest METARs suggest ceilings
will remain MVFR in showers, so have limited amount of IFR through
00Z. Expect IFR to dominate after 00Z, as cool/moist flow around
upr low persists. In addition, rain likely to become more
widespread, and have accounted for that in TAFs. Upr trof begins
crossing region Monday, with dry air in low/mid levels trying to
filter into the region as the day wears on. This should allow for
ceilings to become MVFR everywhere, with some VFR possible toward
the end of the TAF period. The upr low and associated trof will
finally slide e-ne of the region Tue aftn, with slowly improving
OUTLOOK...High pressure surface and aloft builds over the Mid
Atlc States with mainly dry weather Tue aftn thru Fri.
-- End Changed Discussion --
-- Changed Discussion --Sfc low pressure system that impacted the Mid Atlantic coast
yesterday is now located off the New England coast this aftn with
a frontal boundary extending down along the Southeast coast. A
new sfc low is starting to develop invof the Carolinas and is
expected to slowly track nne to just off the Mid Atlantic coast
late tonight into Mon evening...then into New England on Tue.
Meanwhile, an upper level trough sits over the region through Mon
before gradually sliding off the coast Mon night and tracking
into New England on Tue.
Winds generally n 10-15kt this aftn will become ne 15-20kt for
the Bay/Sound/all coastal waters early Mon morning. Expect gusts
to around 25kt coastal waters and mouth of the Bay during the
morning. Seas currently 3-4ft srn waters/4-6ft nrn waters. Seas
become 4-5ft all coastal waters by late this evening...build to
5-6ft Mon morning...then subside to 4-5ft Mon aftn. For srn Ches
Bay, 2-3ft waves will build to 3-4ft Mon morning and then subside
to 3ft in the aftn. For nrn Ches Bay, waves will average 2-3ft.
SCA flags in effect for Sound, all Bay zones, and all coastal
waters through various end times on Mon. Please refer to the
Marine Weather Message (WBCMWWAKQ) for specific details.
Wind speeds diminish Mon aftn as tightened pressure gradient
shifts ewd beyond 20nm. A secondary increase in wly winds may
be possible late Mon night into Tue morning for the mouth of
the Bay and coastal waters south of Cape Charles Light as sfc
high pressure starts to build into the region from the west,
however speeds of 10-15kt should keep the aforementioned areas
(and Currituck Sound) out of SCA flags attm. Conditions finally
quiet down Tue through Fri. Winds will generally be s-sw
aob 15kt. Seas 2-3ft/waves 1-2ft.
-- End Changed Discussion --
MARINE...Small Craft Advisory from 4 AM to 1 PM EDT Monday for ANZ632-
Small Craft Advisory from 7 AM to 4 PM EDT Monday for ANZ633.
Small Craft Advisory from 4 AM to 10 AM EDT Monday for ANZ630-
Small Craft Advisory until 1 AM EDT Tuesday for ANZ650-652-654.
Small Craft Advisory until 8 PM EDT Monday for ANZ656-658.