Scientific Forecaster Discussion
fxus61 kakq 281111
Area forecast discussion
National Weather Service Wakefield Virginia
711 am EDT sun may 28 2017
a warm front will lift across the mid Atlantic this afternoon
into tonight. A cold front approaches from the northwest on
Memorial Day and stalls north of the region into Tuesday.
Near term /through tonight/...
the current surface analysis depicts a weak cold front in
vicinity of the Virginia/NC border as of 08z. The main mid-level
shortwave trough that triggered severe tstms yesterday aftn has
pushed well offshore. However, some lingering shortwave energy
has managed to trigger iso showers/tstms across srn Virginia over the
past few hours. This activity should diminish by sunrise.
Temperatures early this morning range from the upper 50s over
the Maryland ern shore, to the low/mid 60s into central VA, with upper
60s/near 70 south of the front. Some patchy stratus and/or fog
is possible early this morning.
This shortwave trough pushes offshore later this morning, with
shortwave ridging building over the mid-Atlantic through midday.
The surface cold front remains near the Virginia/NC border through
midday with north/NE flow developing north of the Virginia/NC border in
the wake of the mid-level trough and surface cold front. Cooler
over the ern shore with highs in the low/mid 70s. Highs
generally in the low/mid 80s for central/srn Virginia and interior NE
The surface boundary returns newd into the region later this
aftn into the evening and through early overnight hours. This
will combine with another shortwave trough resulting in an
increasing possibility of showers/tstms approaching from the
west during the late aftn and through the evening and early
overnight hours. 0-6km bulk shear rapidly increases to 35-45kt
after 18z resulting in a chc of a strong to severe tstms once
again mainly along and S of the I- 64 corridor. The main threats
are damaging wind gusts and large hail. The shortwave trough
pushes offshore after 06z, with pops rapidly diminishing SW-NE
thereafter. Partly to mostly cloudy overnight with lows in the
Short term /Monday through Tuesday/...
a cold front will be crossing the mountains Monday morning, and
then continue ewd Monday aftn. Additional showers/tstms are
possible Memorial Day aftn/evening. However, the 28/00z model
runs are trending drier with less coverage, mainly confined to
far southeast Virginia/NE NC, and pops have correspondingly been dropped to
the 20-30% range. Increasing west-southwest flow aloft ahead of a trough
digging across the Great Lakes will yield 0-6km bulk shear
values of 40-50kt. This will combine with ~1000 j/kg of 0-1km
MLCAPE resulting in the potential for severe thunderstorms
despite limited coverage and mainly across NE NC. Partly sunny
on Memorial Day with highs in the low/mid 80s, with the
potential for near 90 se, and 70s along the Atlantic coast of
the ern shore.
Current 00z guidance has trended toward the aforementioned cold
front becoming aligned parallel to west-southwest flow aloft and stalling
immediately north of the region to perhaps pushing into the Maryland ern
shore. The chc for aftn/evening showers/tstms will diminish
Tuesday with low chc pops confined to far southeast Virginia/NE NC. Forecast
highs Tuesday range from the upper 70s/low 80s to the mid 80s
inland west of the Bay, after morning lows in the 60s to low 70s
Long term /Tuesday night through Saturday/...
the long term period beginning Tuesday night features near normal
temperatures and generally low chances for precipitation. Weak and
poorly defined frontal boundaries affect the area and confidence in
the details of the precipitation forecast are rather low.
Thunderstorm chances Wednesday were kept relatively low as weak high
pressure builds in. A frontal boundary moves in for Thursday and
settles just off the coast Friday and Saturday. Highest pops (30 to
40 percent) are currently set for southern portions on Friday
afternoon and evening.
High temperatures are forecast to range from 80 to 85 Wednesday and
Thursday and the upper 70s to around 80 Friday and Saturday.
Readings will be a bit lower near the coast. Lows are expected to
range from 60 to 65.
Aviation /11z Sunday through Thursday/...
the current surface analysis shows a weak front in vicinity of
the Virginia/NC border, with light north/NE flow north of the boundary and
light S/SW flow south of the boundary. Fog is affecting ric this
morning and should persist through ~14z. Showers/tstms are
expected again this aftn/evening as another upper level system
interacts with the surface boundary. Sct coverage of
showers/tstms is expected after 18z, with more widespread
coverage after 21z for central/southeast Virginia/NE NC, and then spreading
newd toward sby after 00z. Strong to severe storms are possible
once again with severe wind gusts and hail being the main
threats. A minimal chc for aftn/evening showers/tstms will
persist Monday through Thursday. Stratus and patchy fog is
possible each morning.
latest surface analysis places a cold front near the Virginia
and North Carolina border with high pressure centered off the
northeast coast. The result is onshore flow north of the
boundary and south to southwest flow over the North Carolina
waters. Speeds are generally at or below 10 knots. Waves
generally 1 foot and seas 2 feet. The frontal boundary remains
in the vicinity of the North Carolina and Virginia border today
as a wave of low pressure pushes offshore late today into
tonight. Flow remains onshore at 10-15 knots today, becoming
south to southeast this evening, and then west to southwest late
tonight. Seas build to 2-3 feet, with waves of 1-2 feet. The
front lifts northward Monday as low pressure lifts into eastern
Canada. A trailing cold front stalls near the coast Monday
afternoon. Model differences with waves of low pressure and the
placement of the front/surface trough result in a challenging
wind forecast Monday and Monday night, with flow generally west
to southwest at or below 10 knots. Waves remain 1-2 feet and
seas 2-3 feet. The weak front remains near the coast Tuesday as
a stronger cold front approaches from the west. The next front
pushes across the waters Tuesday night. A lack of cold advection
expected to keep conditions sub-Small Craft Advisory Tuesday night. High
pressure builds into the region Wednesday, centering over the
waters on Thursday. High pressure slides offshore Friday.