Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
935 am EDT Monday Aug 3 2015
high pressure remains over the region through tonight. A weak
cold front enters the area Tuesday...then stalls across the middle
Atlantic region Wednesday through Friday.
Near term /through tonight/...
adjusted grids a bit per current trends. Precipitation now well south of the
region so dropped probability of precipitation across NE NC zones for the next few hours. Msas
indctg surface boundary located across southeastern Virginia snaking its way SW into the
NC Piedmont. High res data suggests scattered convection dvlpng along
and south of this boundary aftr 18z...so kept 20-30 pop there...
highest ivof alremarle sand. Cdfrnt remains well northwest of forecast area today with
surface trough dvlmng out ahead of it. Latest data shows little if any
sprt for convection with this feature. Hot and a bit more humid
with highs in the l-m90s...xcpt u80s at the beaches. Heat index
values expeceted to remain below 100.
M clear to pt cloudy tonight. Weak shear and best forcing/moisture
remaining to the south of the area should allow for any lingering
convection to quickly diminish after sunset. Lows u60s-l70s except
m70s beach areas.
Short term /Tuesday through Thursday/...
eastern trough sharpens a bit more to allow the approaching frontal
boundary to drop across the forecast area from the north. Best dynamics/forcing
look to remain off to our north. However, low level convergence,
moisture/relative humidity pooling ahead of the approaching boundary and diurnal
instability all seem to point toward scattered convection developing,
with best areal coverage expected from central Virginia over to the Northern
Neck and Eastern Shore, where chance probability of precipitation will be maintained. Otw, will
carry slight chance across the southeast farther away from better forcing
and lift. Highs once again 90-95...but will feel a bit hotter with
increased humidity. Slightly cooler u80s to around 90 again at
coastal/beach areas. Any convection dissipates after sunset. Mild Tuesday
night west/lows u60s-m70s.
Boundary washes out / dissipates over the region Wednesday/Thu, as flow
aloft becomes quasi-zonal. Have maintained a slight chance/low chance
pop for isolated to widely scattered diurnally driven convection, as
additional weak perturbations push across the region. Continued
very warm and still moderately humid with highs u80s-l90s.
Heat index values are elevated each day through the period and should
top out ~ 100 degree f Tuesday/Wednesday with the highest values across
interior southeastern Virginia/NE NC.
Long term /Thursday night through Sunday/...
long term period will feature frequent chances of rain with slightly
decreasing temperatures through the period. Tough to time exactly when best
chances will be but the forecast calls for a 30-40% chance of
rain showers/thunderstorms each afternoon/eveng through Sat...and a 20-30% chance each
night/morng. Pattern will feature an upper-level trough over the far eastern
Continental U.S. With transient shortwave troughs passing through the middle Atlantic
region. As for temperatures...highs will drop from the upper 80s/lower 90s Thursday
to low/middle 80s Sat and sun.
Aviation /14z Monday through Friday/...
update...showers riding along the Carolina coast this morning
should stay south of Albemarle Sound. Therefore do not expect any
impacts to flight conditions at kecg.
Previous discussion...a weak frontal boundary draped across far
southeast Virginia and NC early this morning will be shunted southward through today
as a cold front approaches the region from the W-NW. VFR
conditions will prevail today with south winds becoming breezy by
this afternoon. There remains a slight chance of late day showers/storms
at kecg... otherwise the remaining taf sites will be dry during
the next 24 hours.
Weak low pressure moving up the southeast coast will merge with
the incoming front and develop into an elongated trough along the
middle Atlantic coast Tuesday and Wednesday. Convective showers/storms
should be anticipated east of the trough axis both aftns/evenings.
Breezy SW winds persist on Tuesday... becoming more west-northwest and light
on Wednesday. Conditions become more unsettled Thursday/Friday as weak low
pressure develops over the Carolina coastal plain with weak high
pressure just north of the region.
a weak frontal boundary draped across far southeast Virginia and NC early
this morning will be shunted southward through today as a cold front
approaches the region from the W-NW. Predominantly S-SW winds
will average at or below 15 knots...becoming more breezy by this afternoon.
Low-end Small Craft Advisory wind speeds are expected during the late
afternoon/early evening hours over the Bay/sound and coastal
waters north of the Virginia/NC border...persisting into early
Tuesday morning. Speeds will range from 15-20 knots with gusts
to around 25 knots over the aforementioned coastal waters.
1-2 feet waves build to 3-4 feet this evening...and 2-3 feet seas
will build to 3-5 feet. Wind speeds will fall below 15 knots
around daybreak Tuesday morning...however seas will be slow
to drop below 5 feet until early afternoon.
Weak low pressure moving up the southeast coast will merge
with the incoming front and develop into an elongated trough
along the middle Atlantic coast Tuesday and Wednesday. Convective
showers/storms should be anticipated east of the trough axis
both aftns/evenings. Breezy SW winds persist on Tuesday...
becoming more west-northwest and light (aob 10 kt) on Wednesday.
Conditions become more unsettled Thursday/Friday as weak low pressure
develops over the Carolina coastal plain with weak high
pressure just north of the region. For Tuesday through
Thursday...expect S-SW winds at or below 15 knots and waves 1-2 feet/seas
2-3 feet (up to 4 feet at times near 20 nm).
Marine...Small Craft Advisory from 4 PM this afternoon to 7 am EDT
Tuesday for anz630>634.
Small Craft Advisory from 4 PM this afternoon to 1 PM EDT
Tuesday for anz650-652-654.
Small Craft Advisory from 8 PM this evening to 7 am EDT
Tuesday for anz656.