Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
215 PM EDT Thursday Oct 30 2014
a cold front continues to push farther offshore today.
Meanwhile...weak high pressure builds across the area through
Friday. A strong low pressure system will develop off the middle
Atlantic coast Saturday and Saturday night before exiting the
area on Sunday. High pressure returns for the beginning of next
Near term /through tonight/...
midday surface analysis indicated surface cold front well offshore, extending
into the deep south. Meanwhile, ~1022mb surface high pressure
continues to build into the region from the west-northwest. Little change made to
the going forecast for the balance of the day. Mostly sunny inland
with continued clearing over southeast zones through the afternoon. Afternoon high
temperatures ranging from the l/m60s north-northwest to M/u60s south-southeast.
Surface high builds over the region tonight...with low temperatures into the
M/u30s inland to around 50f along southeast coastal areas...under a clear to
mostly clear sky.
Short term /Friday through Saturday/...
forecast area to be in between frontal boundary (well) off the CST and strong upper
level system diving southeast from the lakes/Ohio Valley Friday into Friday night. Starting
out clear Friday morning...with vrb/incrsg clouds through the afternoon. Hi
temperatures from the u50s far northwest to l/m60s elsewhere.
All models continue to show dynamic weather system develop in vicinity of mdatlc CST from
lt Friday through Sat. Strong upper level low pressure continues to dive east-southeast
through the Carolinas...while at same time...surface low pressure slowly
develops off the CST (invof lingering frontal bndry). Given forecast of
how far S upper level system tracks...most significant impacts from this storm
situation Apr to be for eastern/coastal locations (primarily) from Sat afternoon
into 1st part of Sat night. Probability of precipitation to increases throughout the day
Sat...W/ highest probability of precipitation (60-80%) near the CST...to mainly 30-50% probability of precipitation
elsewhere. Additionally...incrsg concern to strong north-northeast winds (to 35-45
mph) near the CST along west/ minor to ptntlly moderate coastal flooding
(invof southern Bay...along the Atlantic beaches). Will highlight ptntl
impacts in severe weather potential statement.
Low temperatures Friday night mainly in the l/m40s inland to around 50f at the
immediate CST. Hi temperatures Sat in the l/m50s inland to around 60f near
Long term /Saturday night through Wednesday/...
windy/rainy Sat evening (close to the cst) as storm strengthens offshore.
The surface low begins to exit the mdatlc coastal waters after mdngt Sat night.
Clearing from the west will begin after 03-06z/02.
Strong high pressure builds into the middle Atlantic Sunday...before
settling over the region Sunday night and Monday. A much cooler
airmass will accompany the high pressure system. Highs Sunday
should only rise to 50-55 under a mostly sunny sky as cold air advection
continues. The high is expected to settle over the region Sunday
night...with lows falling to around 30-32 for much of the area
(upper 20s possible in favored cold spots)...with slightly higher
values (35-40) for far southeast portions. This has the potential to
produce the first widespread freezing temperatures this fall
(inland) across the local area. A slow moderating trend is
expected Monday through Wednesday as the high gradually moves
offshore. Highs Monday should range from 55-60...with low/middle 60s
by Tuesday and Wednesday. Overnight lows should remain rather cool
Tuesday morning ranging from the low/middle 30s interior to low 40s
for southeast coastal locations. Lows should moderate into the low/middle
40s Wednesday morning. The next cold front approaches from the northwest
during the middle of next week. Confidence is rather low with
respect to the strength and associated moisture with this front.
Aviation /18z Thursday through Tuesday/...
hi pressure will build into and over the area tonight into Friday morng...then
dissipates over the region Friday afternoon. Upper air/surface low pressure will then
affect the region Friday eveng into Sat night. Expect VFR conditions
into Friday eveng...then lower ceilings/visibilities possible due to rain Friday night
into Sat night. Hi pressure and VFR conditions return for sun and Monday.
sca's have been extended through 10am for coastal waters S of the Virginia/NC
border where 5 feet seas persist...and Currituck Sound due to 15-20
knots winds. Sub-Small Craft Advisory conditions have commenced over the mouth of the
Bay so headlines have been cancelled there. For today...expect north
winds avgg 10-15 knots as a cold front pushes S of the area and broad
surface hi pressure builds in from the west. Similar winds into tonight with weak hi
pressure over the middle Atlantic. The hi dissipates by Friday...with
conditions remaining sub-Small Craft Advisory (10-15 knots north winds and 2-3 feet seas).
A vigorous upper level trough is then expected to cross the region
Friday night and Saturday...followed by strong cold air advection later Saturday
into Sunday as Canadian high pressure builds in from the northwest. A north-northwest
wind is expected to quickly increase Saturday afternoon and a period
of gale conditions is increasingly likely Saturday afternoon into
Saturday night...followed by Small Craft Advisory conditions lingering through Sunday
night. If rapid cyclogenesis eventually occurs off the Virginia coast a
brief period of storm force gusts is possible over the Lower Bay and
ocean during the late Saturday afternoon/Saturday evening timeframe.
High pressure builds over the area Sunday night and Monday and then
slowly moves offshore early next week.