Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
207 am EDT sun Jul 5 2015
unsettled weather conditions will prevail through the Holiday
weekend as a frontal boundary oscillates north and south across
the region. The front finally lifts north of the area Monday night
into Tuesday ahead of the next cold front that should move into
the local area late in the week.
Near term /until 6 am this morning/...
the current surface analysis indicates low pressure southeast of Cape
Cod...with a trailing boundary extending SW back into eastern/southern Virginia.
Weak high pressure is centered over the Great Lakes region.
Aloft...somewhat of a split flow pattern exists...with one upper
trough over eastern Canada...and another lagging well off to our SW
across the deep south/Gulf Coast states. The current radar mosaic
shows a line of showers/thunderstorms moving off the Virginia Eastern Shore...with
isolated-scattered activity back across Southside Virginia. This is associated
with the surface boundary...and upper level rrq forcing from
250-300 mb upper level jet.
Overall...radar data suggests a diminishing trend...and rap/hrrr
support this as well. Given this...probability of precipitation have been trended down
overnight. Otherwise...variably cloudy northwest to mostly cloudy southeast. Lows
in the middle-upper 60s northwest to the lower 70s southeast.
Short term /6 am this morning through Tuesday/...
frontal boundary looks to stall near or just south of the Virginia/NC
border early sun...then will move back north once again later sun into
Monday as low pressure surface-aloft lifts NE from the Gulf states to the central
mountains there remain some model inconsistencies in this scenario...largely
relating to timing and where axis of highest quantitative precipitation forecast takes place.
The favored area of additional rain showers/thunderstorms on sun likely to be from
scntrl Virginia to interior NE NC in vicinity of stalled frontal boundary. Mostly
cloudy S...partly cloudy NE sun. Hi temperatures sun mainly in the l/m80s.
NAM/GFS/ECMWF into good agreement that deep moisture and lift will
push into SW portions of the area sun evening...and slowly spread
north/NE overnight into Monday. This will support likely probability of precipitation once again
across most of the County Warning Area (will keep probability of precipitation a little lower along the
coast). Most low temperatures Sun night in the u60s-l70s. Vrb clouds- mostly
cloudy Monday west/ highest probability of precipitation transitioning a bit to the north/west as upper
low approaches the central Appalachians. Hi temperatures in the l 80s northwest
to the upper 80s southeast. Finally looks a bit drier by Tuesday...with just
20-3% probability of precipitation mainly in the afternoon/evening with highs in the middle-upper
80s/around 90 f.
At this time...total quantitative precipitation forecast through Tuesday (most of it occurring tonight into
mon) will average 1.Oo-1.50 inches central/scntrl Virginia to interior NE
NC...tapering to an average of about 1/2 inch over the lower Maryland Eastern Shore.
However...lclly much higher amts are certainly possible due to hi precipitable waters
(1.75-2 inches)/slo moving or repeating shras/tstms. Will highlight
ptntl in severe weather potential statement.
Long term /Tuesday night through Saturday/...
a more typical summertime pattern develops by the middle and end of
the coming week as a sub-tropical ridge tries to build over the southeastern
U.S. And a series of disturbances pass mainly north of the local
area. Widely scattered after/evening thunderstorms will be possible each day (20-30%
pop). A cold front may drop south into the local area next Fri/Sat.
Lows through the period in the upper 60s to middle 70s. High temperatures in the
upper 80s to low 90s...except low/middle 80s at the beaches.
Aviation /06z Sunday through Thursday/...
early this morng...frontal boundary was laying across southern Virginia...with just
isolated showers over scntrl/southeast Virginia and NE NC. That front will lift
back north across the region as a warm front this afternoon into Monday. Expect
IFR conditions at sby and possibly ric early this morng...then
mainly MVFR or VFR conditions after 13z-14z. More scattered showers and
thunderstorms will return for later this afternoon into Monday...due to frontal
boundary lifting through the area. The front will move north of the region
Monday night/Tuesday morng...with a more typical Summer pattern expected
for Tuesday into Wednesday. Isolated late afternoon/evening thunderstorms will be possible
those two days.
a frontal boundary draped across the Maryland waters this afternoon
will drop south this evening and tonight before stalling along the
Virginia/NC border on Sunday. Mainly west-SW winds at or below 15 knots this afternoon
will veer around to the north-NE behind the front tonight...except
near/south of the Virginia/NC border where they'll remain west-SW at or below 15 knots.
Surface high pressure pushes off the middle-Atlantic coast on Sunday with
winds becoming east-southeast at or below 15 knots all waters. Light east-southeast winds continue
into Monday before becoming S-SW at or below 15 knots Tue/Wed. Seas will
generally remain 2-3 feet through midweek...with waves 1-2 feet on the