Area Forecast Discussion
Issued by NWS Wakefield, VA-- Remove Highlighting --
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FXUS61 KAKQ 292352 AAA
Area Forecast Discussion...UPDATED
National Weather Service Wakefield VA
752 PM EDT SUN MAY 29 2016
Tropical Depression Bonnie will linger along the South Carolina
coast tonight, and will slowly track northeast along the coastal
Carolinas while weakening further through the middle of the week.
.NEAR TERM /THROUGH MONDAY/...
Latest analysis indicating TD Bonnie now located just inland of
Charleston SC (was downgraded from a tropical storm earlier today).
Please continue to refer to discussions/forecasts issued by the
National Hurricane Center for the track on TD Bonnie. Upper level
ridge has retreated farther off the Mid-Atlc coast and widespread
showers have been affecting the CWA this aftn.
WV/IR imagery and radar trends support continuing Likely to
Categorical POPS into early evening for most areas, though skies
are partially clearing over ern NC and will probably see some
sunshine from time to time through sunset over southern VA and ne
NC. High res models suggest the highest POPS/categorical will
tend to shift to the N/NW zones after 00z, with high- end chc
POPS persisting acrs the south. Has not been much in the way of
lightning activity so far, but will maintain isolated tstm
mention/scattered acrs the south. Main issue tonight will continue
to be locally heavy rain, noting 12Z sounding from MHX at 2.18
PWAT (1.68 at WAL per 12Z), and latest SPC mesoanalysis shows
PWATS now to be 2.00" or greater cwa-wide. Steering flow/MBE
vectors suggest best chc for training cells has been along the
coast, while storms move a little faster farther inland. This may
change a bit this evening though as BUFKIT data suggests training
becomes more of an issue inland as well. Will mention heavy rain
in the gridded database acrs NW 1/2 of the cwa this evening due
to high precip rates and additional potential localized flooding.
Temps remain warm/humid this evening with lows genly 65-70 F
TD Bonnie or it`s remnant low is very slow to weaken acrs SC and
get slowly transported NE later tonight as broad, Upper level
troughing pushes in from the SW. Bulk of widespread and heavy
precip may weaken for awhile late in the evening/early morning,
but expect to see it regenerate early Mon morning as increasing
lift returns which will be further enhanced by upper divergence
provided by RRQ of upper jet. Sfc trough remains centered inland,
and gradually shifts east towards the coast by Mon aftn. Will have
80% POPS most areas Mon morning, some drying NW by aftn, but will
maintain 60-80% POPS through the aftn elsewhere. Additional
periods of locally heavy rain are likely with QPF amounts through
mon evening to avg 1-2", more of this overnight/mon am west of
I-95, and on Mon farther east. highs Mon held in the mid-upper 70s
due to clouds and widespread precip.
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
TD Bonnie (or more likely the remnant low) looks to very slowly
lift NE along the SC/NC coast through the period. Continued
humid,though dew pts lower slightly into the mid 60s by Tue. Highs
avg in the upper 70s/lower 80s both Tue-Wed with lows in the lower
60s NW to the upper 60s SE. Above climo POPS of 40-50% SE and
20-30% NW persist Mon night-Wed.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Model consensus and NHC forecast centers Tropical Depression Bonnie
(or the remnant low) just off the Mid-Atlantic coast Thursday. An
upstream trough and associated cold front approaches from the west.
Will keep mention of chance POPs along the coast, as well the
Piedmont as moisture increases from the west. Expect subsidence over
central VA and hopes for dry conditions, but will keep slight chance
POPs. Expect increasing clouds Thursday night as the approaching
trough finally kicks off the coast in advance of the approaching
upstream trough. Will keep mention of slight chance POPs, but
overall dry conditions expected. The front drops into the forecast
area Friday with increasing chances for showers and
afternoon/evening thunderstorms. Latest guidance now in good
agreement with cutting off mid level energy over the Southern
Plains, with the largest height falls over New England. Sensible
weather impacts will be a quicker departure of the front off the
coast Friday night into Saturday than previously forecast. Will keep
mention of chance POPs Saturday, will drying conditions into
Saturday night. Only a slight chance POP across the southeast
forecast area for Sunday as the front stalls over the Carolinas in
westerly flow aloft. Sky generally partly cloudy Sunday.
Highs in the low to mid 80`s Thursday and Friday cool only a few
degrees into the upper 70`s to low 80`s Saturday and Sunday. Lows
in the 60`s.
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --Circulation and moisture associated with T.D. Bonnie will
continue to be the primary weather maker for the next 48-72 hours.
Initial surge of shower/tstm activity has cleared all terminals
but KRIC, where localized convergence zone will keep precipitation
and IFR conditions going for at least another 2 hours. Additional
scattered showers moving northward toward KECG, and will affect
that terminal through 03Z. biggest questions next 12 hours will be
future areal coverage and intensity of precipitation and amount of
fog/stratus development overnight. Think IFR will be predominate
at KRIC through at least 12Z Monday, as that terminal will be
closest to inverted surface trough. Models have been very
consistent in bringing stratus into KECG, and have followed
previous forecast in that realm. Have also shown an increase in
stratus at KPHF/KSBY and KORF, with IFR conditions all 3 terminals
overnight. Timing and intensity of precipitation the hardest to
pin down, and have used current radar trends, and hi-res model
guidance for the next 6-12 hours.
thereafter, think all terminals will slowly become mvfr by mid to
late Monday morning. However, airmass will be marginally unstable,
which means at least scattered showers and isolated thunderstorms
will be possible at any time. Have not tried to time precipitation
after 12Z Monday due to more scattered nature, and inconsistency
of model guidance.
Outlook...low pressure/remnants of Bonnie to the north will slowly
move along the north carolina coast through Tuesday. A weak cold
front moves across the region Tuesday aftn/night, temporarily
shifting deepest moisture to/east of the coast. However the
weakening/remnant tropical low pressure system is expected to
linger near the Carolina coast through the middle of the week and
keep rain chances in the forecast during this time, with highest
chances along the coast. A stronger cold front moves into the area
-- End Changed Discussion --
Latest surface analysis centers Tropical Depression Bonnie just east
of Charleston SC this afternoon. High pressure has pushed well
offshore. Obs indicate southeasterly winds around 10 knots. Waves 1-
2 ft and seas 3 to 4 ft. Bonnie is expected to make very little
northward progress Monday as a coastal trough sets up along the Mid-
Atlantic coast. A wave of low pressure lifts along the front Monday
afternoon over the Bay. Winds remain southerly over the waters at or
below 15 knots Monday, but become light and variable behind the wave
Monday night. TD Bonnie locates over eastern NC Tuesday with flow
becoming onshore at or below 10 kt. Waves remain 1-2 ft and seas 3-
4ft. The gradient strengthens Tuesday night and Wednesday as the low
locates in the vicinity of the Currituck sound. Onshore flow ramps
up to around 15 kt Wednesday, with SCA conditions possible. Seas
also build to 4 to 5 ft Weds. Waves 2-3 ft (up to 4 ft mouth of the
bay). The low lifts off the Mid-Atlantic coast Thursday with flow
becoming northerly. A cold front is forecast to reach the waters
late in the week into next weekend. Sub-SCA conditions expected.
For more information on TD Bonnie, please refer to NHC.
The monthly rainfall total to date for May at Richmond prior to
today had been 8.41", ranking as the 6th wettest month of May on
record at Richmond. Rain has occurred today and with additional
rain over the next 2 days, there is good potential to end as the
wettest May on record.
Top 6 wettest months of May at Richmond
1. 9.13" 1889
2. 8.98" 1873
3. 8.87" 1972
4. 8.67" 1886
5. 8.59" 2003
6. 8.41" 2016 (to date)