Area Forecast Discussion
Issued by NWS Wakefield, VA-- Remove Highlighting --
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FXUS61 KAKQ 291110
Area Forecast Discussion
National Weather Service WAKEFIELD VA
710 AM EDT Wed Mar 29 2017
A cold front pushes farther offshore this morning. High
pressure builds across the northeast today, before it retreats
to the northeast on Thursday. A strong system is expected to
impact the region Friday and Friday night. Dry weather returns
for the weekend.
.NEAR TERM /THROUGH TONIGHT/...
Latest upper air analysis reveals a dampening upper level trough
now oriented offshore of the Mid-Atlantic/Northeast coast. In
its wake, shortwave ridging continues to build northeast from
the Mississippi River Valley into the OH/TN Valleys. Farther
west, a strong closed low continues to slowly cross the Southern
High Plains this morning. At the surface, surface trough now
aligned just offshore, with ~1034+ mb sfc high pressure
centered from Hudson Bay down into Western Ontario and now
dropping south across the Upper Great Lakes.
As expected, have noted some patchy fog across South Central VA
into Interior NE NC over locations that received between 0.5 and
1" of rainfall Tuesday aftn. As post-frontal NNE flow continues
this morning, expect areal coverage to remain limited, but
have accounted for lingering low stratus/patchy fog early this
morning. Otherwise, look for clouds to eventually give way to
a partly/mostly sunny sky as drier air moves in from the N.
Somewhat cooler, but still expecting temperatures near to a
little above average with highs 60-65F near the coast and in
the upper 60s to lower 70s well inland.
Upper ridging pulls overhead tonight as upper trough lifts
across KS/OK late tonight. At the surface, high pressure nudges
south from Eastern Canada/New England tonight, with low level
flow becoming E-NE and increasing. Lows in the mid 30s to near
40 across far northern zones, low to mid 40s farther south...mid
to upper 40s along far SE coastal zones. Sky begins mainly
clear, but expect some increasing mid to high clouds toward
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Dry Thursday, with upper ridge in place overhead. However, WAA
aloft atop the stable onshore flow will likely result in partly
to mostly cloudy sky Thursday and model BUFR soundings continue
to suggest mostly cloudy to overcast conditions inland by 18z
Thu (partly sunny eastern sections). Given weak/low mixing and
the increase in clouds, expect a much cooler day with highs
mainly ranging from the lower to mid 50s near the coast to the
upper 50s over interior eastern VA/northeast NC.
Models coming into increasing agreement with handling of
previously mentioned upper low currently pushing slowly across
the Southern High Plains. 00z NAM has come into better agreement
with the GFS/ECMWF solutions, which all feature a strong closed
low lifting across the Missouri Valley, and taking on a
negative tilt as it lifts across IN/OH by Friday morning. Good
model agreement exists with respect to onset of showers and
embedded t-storms late Thursday night/Friday Morning from west
to east. Similarly good agreement with respect to potential for
widespread showers/tstms and potential for heavy rain during
Fri, which makes sense given the negative tilt, PW values in the
1.25-1.5" range (>150% of normal) and flow aloft parallel to
the encroaching frontal boundary. quickly expand pops just
before sunrise west of I-95 before increasing to 80% to 90% all
areas during Fri morning.
Categorical pops continue Friday aftn as the upper low tracks
east across the mountains Friday afternoon and night. There
remains every indication that we`ll have the chance for some
strong to locally severe storms once again during this time
frame. Given the trend towards the quicker solution, storms will
move out quicker and there will be less time for diurnal
destabilization, so it is certainly a conditional threat.
That said, strong 0-6km shear values, Lifted Indices of
<-4 deg C coincident with timing of best forcing onset Friday
aftn would at least argue favorably for continued mention of
thunder in grids, especially across the southern 2/3 of the
area. Lowered pops Friday night given quicker timing, with
clearing into Sat morning. as front crosses the area late
Friday. Highs in the 60s to near 70. Lows Sat morning in the low
to mid 50s, with some upper 40s across our far northern tier of
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Low pressure and associated surface cold front cross the area
Friday night then moves off the coast. Dry wx and high pressure
returns for Sat thru at least Mon morning. Yet another system
will bring the chc for showers back to the area late Mon thru
Highs in the mid 60s to lower 70s Sat, in the 60s to near 70
Sun and Mon, and in the 60s to lower 70s Tue. Lows in the upper
40s to mid 50s Fri night, in the 40s Sat night and Sun night,
and in the mid 40s to lower 50s Mon night.
.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --Predominate VFR conditions across area terminals, with only
localized Visibility/Ceiling restrictions in light N-NE flow.
This will result in some ceilings localized LIFR/IFR cigs for a
brief time early this morning in low stratus, with some
patchy fog in areas that picked up ~1" of rain late Tuesday.
Skies will scatter out and lift from north to south this morning
as high pressure slowly nudges into the region from the north.
Outlook: Dry w/ VFR conditions tonight through Thursday.
However, clouds will increase on Thursday as another front
approaches the region. Clouds then thicken and lower Thursday
night as the next low pressure system approaches the area w/some
patchy drizzle and IFR as early as Thursday evening. This
system should bring widespread showers and thunderstorms to the
area Friday/Friday night as it crosses the Mid-Atlantic region.
-- End Changed Discussion --
Latest sfc analysis shows a cold front sliding off the Carolina
coast with high pres over the Great Lakes region. The front
will push farther offshore today as the high builds north of the
region. Resulting north winds will increase this morning in
association with weak CAA/pres rises. Currently expecting
sustained winds up to ~15 kt with a few gusts up to 20 kt psbl
over the Bay...but no SCA hazards issued attm. Also, seas will
build close to 5 ft out 20 nm this aftn but confidence is not
high enough to issue a SCA there also as seas should mainly cap
out around 4 ft there. Conditions just sub-SCA again tonight
with NE flow of 10-15 ft over the Bay/rivers/Sound and 15-20 kt
over coastal waters. Similar conditions into Thu morning with
seas near 5 ft out 20 nm over the coastal waters. Next cold
front then approaches from the west Fri, with marginal SCA S/SE
flow expected ahead of the front. This front crosses the waters
late Fri night/Sat morning.