Area Forecast Discussion
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FXUS61 KAKQ 271804
Area Forecast Discussion
National Weather Service Wakefield VA
204 PM EDT MON JUN 27 2016
High pressure shifts off the Mid Atlantic coast today, as a cold
front slowly approaches from the west. The front will move across
the region Tuesday and Tuesday night. Weak high pressure builds in
from the north Wednesday and Thursday as the front stalls across
.NEAR TERM /THROUGH TONIGHT/...
Latest GOES water vapor imagery depicts anticyclonic flow over
the Southeast states late this morning. The result is a mostly
sunny to sunny sky and dry conditions after some early morning
patchy fog. Temps have warmed into the mid to upper 70`s late
morning. Ongoing forecast is on track, so no changes made. Hi-
res guidance still indicating a weakening line of showers ahead
of the front tonight, while course resolution models keep the
showers together moving into the region. With the lack of upper
level support and warm temperatures aloft, the hi-res guidance may
be onto something. Have kept POPs unchanged and will await new
guidance before making adjustments.
Today will be a transition from the dry/pleasant weather
yesterday when dew pts were primarily in the 50s to one with
increasing moisture and humidity as the low level flow veers
around to the south. However, still should have a dry day for most
areas as showers and tstms develop along the Mtns this aftn and
will be slow to push east into the CWA. Model consensus continues
to support a broken line of showers and tstms beginning to affect
the NW zones sometime late in the aftn, primarily after 20-21Z,
with the better chance for storms not making it to areas e and SE
of metro Richmond until after 00Z. Have made some minor
adjustments to the forecast to best reflect these trends. Highs
today will avg in the upper 80s well inland to the upper 70s to
lower 80s along the immediate coast (gradient not strong enough to
completely keep the typical backing of the wind direction to the
SE closer to the coast). Skies will start off mostly cloudy along
the coast and become mostly sunny later this morning. Farther
inland expect partly to mostly sunny skies for most of the day
with increasing clouds late over the NW.
Precipitable Water values surge rapidly to around 2.00" this
evening/overnight ahead of the approaching cold front. POPS ramp
up to likely most areas during the 00-06Z/tue timeframe, though
far SE VA and ne NC look to stay mainly dry through that time as
shortwave energy rides ENE along or slightly ahead of the cold
front. Severe threat for strong wind gusts appears to remain just
NW of the area closer to the main jet axis and where storm
coverage will be greater prior to sunset and coincident w/ optimal
instability. However, The high PW airmass will support this
potentially being a moderate to locally heavy rainfall event.
Furthermore, the flow aloft will not be that strong from the NW
and shifting to the W with low level flow from the SW, creating a
fairly slow storm motion and perhaps some training cells. Still not
enough confidence to issue a Flash Flood watch, as some of the
models depict storms diminishing after sunset w/ loss of daytime
heating while others shows coverage of storms maintaining through
the night. Will mention potential for heavy rain/flooding in the
HWO (mainly NW). Thunder chc greatest through 06z. Lows in the upr
60s to lwr 70s. QPF through 12Z Tue to avg 1.00-1.50" far NW and
0.50 to 1.00" or less elsewhere (but with locally higher amounts
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
The boundary will be slow to push across the region Tuesday as
the upper trough and associated cold front slowly moves east.
Additional shortwave energy will maintain decent amount of lift
across the SE half of the region and have bumped even the morning
POPS to likely across this region (30-40% elsewhere). The
greatest threat for heavy rain will be across the SE. By aftn,
potential for some clearing which could lead to additional storm
development. Highs in the low to mid 80s except upper 70s to lower
80s SE sections with more widespread low clouds all day.
Convection slowly wanes Tuesday night as drier air arrives in the
wake of the front, but upper level shortwave passing across the
north may be enough to set off a secondary line of showers/tstms
Tue evening, especially across the north. Lows 65-70 F.
Broad, upper level trough pushes across the region Wed. This will
likely be enough of a trigger for sct convection to develop once
again mainly during the afternoon / evening hours, over the south
(probably becomes too dry over the north by aftn). Highs in the
mid 80s except upr 70s to lower 80s at the beaches.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
The cold front will have pushed well offshore by Wednesday morning
with high pressure building in and dominating the weather Wednesday
into Thursday. model hint at a few possible showers along the
Sound Wednesday night into early Thursday...otherwise dry
through mid week with high in the low to mid 80s.
The weather pattern becomes more unsettled Friday as a broad upper
level trough dominates Thursday night into the holiday weekend. Have
increased POPS to high chance over much of the area with the
exception of the Eastern Shore Friday afternoon. Showers and storms
look to develop late after strong heating with highs Friday in the
mid to upper 80s. The pattern changes very little into the holiday
weekend with another front pushing though Saturday night into
Sunday. This will keep a good chance for showers and storms in the
forecast through the weekend. At some point POPS will likely have to
be increased for the timing of the front.
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR conditions are expected through this evening at all sites.
Showers and thunderstorms over the mountains will attempt to move
into the region tonight, however it is unclear how widespread they
will become. If nothing else, ceilings will lower overnight at all
sites and may become MVFR late tonight into Tuesday. There are
chances for thunderstorms late tonight, but confidence is not high
enough to include in any terminal at this time. Best chance for
thunder would be at RIC. Continued MVFR or lower end VFR on Tuesday.
OUTLOOK...Chances for thunderstorms will continue Tuesday afternoon
into Wednesday as the front moves slowly through the area. This
front remains just south of the area through Friday, and with that a
chance for showers and storms, especially at ORF and ECG.
High pres was cntrd just off the New England and nrn Mid Atlc cst
early this morning, while a cold front was pushing thru cntrl OH
and wrn KY. No headlines in the short term today thru Tue ngt. The
high will slide farther e into the Atlc during today, as a pre-
frntl trough approaches fm the wnw. Winds will become SE or S and
increase to 10 to 15 kt for this aftn into tngt. A band of showers
and some thunderstorms will approach the Ches Bay and coast later
tngt into Tue morning, as the pre-frntl trough slides into and
acrs the region. Winds will lessen a bit and become SSW as the
trough moves in. SSW flow 5 to 15 kt continues Tue into Tue ngt,
as the actual cold front approaches fm the wnw. The cold front and
wind shift to a N and NE wind drops through the waters Wed morning
into Wed aftn with high pressure pushing into the Grt Lks and OH
valley. This will maintain a NE to E flow Wed and Thu.
Chances to add to an already wet month mainly tonight and Tue. June
has been another wet month at Richmond, the monthly total rainfall
through the 24th stands at 6.92" and already makes this the 9th
wettest June on record (2004 is wettest June with 9.93").