Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
352 am EST Wednesday Nov 26 2014
low pressure will track northeast along the middle Atlantic coast
today...then quickly move northeast and away from the area tonight.
A secondary low tracks across the region Thursday. High pressure
builds in from the west Thursday night into the weekend.
Near term /today/...
low pressure off the Carolina coast this morning will deepen as it
quickly moves NE along the middle atlntc coast this afternoon and evening.
Models continue to indicate deep moisture along with good dymncs through 18z
with dmnshg effects as the best sprt moves NE of the area by 00z.
Expect MDT to occasional heavy rainfall with 100 probability of precipitation through the Erly afternoon hours
forecast area wide. Temperatures slowly falling from the 12z readings. Temperatures by afternoon
range from the m30s-l50s. Forecast becomes problematic across xtreme
northwestern counties between 14z-20z. Cold air advection remains rather weak...but intensity of
the precipitation will likely cause enough dynmcl cooling for surface temperatures to
drop into the middle 30s. This will likely result in a several hour prd of
mixed rain/wet snow if not all wet snow across portions of Louisa
/ Fluvanna counties. Slushy accumls of a dusting to 1/2 inch possible
(louisa - palmyra) with amts of 1/2 to around 1 inch closer to the
Albemarle County line (boswells tavern - antioch). Expect any accumls
would mainly be on grassy/elvated sfcs. A rain/snow mix is also
possible across Caroline / Hanover / on NE into the Northern Neck for a
few hours...but no accumls are expeceted there. No advsrys planned
at this time...but have put a bit more detail in morning severe weather potential statement.
Moisture Shallows aftr 18z..so precipitation should steadily lessen in
intensity before ending late afternoon or early evening. Locations that
change to snow could actually Switch Back over to -ra as precipitation
intensity wanes. A decent soaking expected with total quantitative precipitation forecast amounts
ranging from 2/3rds to 1 inch west of the Bay...1 to 1.5 inches
along the coast.
Short term /tonight through Friday/...
coastal low and assctd precipitation quickly move NE this evening...but enough left
over moisture seen in tsctns for lingering rain or mixed rain/snow showers
this evening. Kept a 20-30 pop. Models then show a several hour prd of "non
eventful" cndtns from late evening through Erly morning hours as first
systm leaves but with a secondary impulse hot on its heels aftr 09z.
Models differ a bit timing and moisture wise...but will keep chance probability of precipitation
across western counties late tonite. Thermal profiles and time of day
suggests snow showers (nrn cntys)...rain/snow shower mix nrth of Virginia/NC
line to say i64...remaining liquid across southeastern Virginia and NE NC. Lows
30-35 xcpt u30s southeastern coastal areas. No accumls anticipated but a
dusting of snow can't be ruled outm in any snow shower.
Short wave tracks across the forecast area Thursday morning...moving off the coast by late
in the day. Mostly cloudy with chance morning probability of precipitation (rain/snow shower mix)
with temperatures in the m30s-l40s...then becoming pt sunny with slght chance probability of precipitation
in the afternoon as temperatures slowly rise into the 40s.
High pressure builds into the area from the west Thursday night and
Friday. Expect clearing skies & dry conditions for those early morning
Holiday shoppers. Lows in m20s-l30s. Highs Friday in the l-m40s.
Long term /Friday night through Tuesday/...
going with a blend of the 12z/25 GFS/European model (ecmwf) for the extended
period. Will have a mainly dry forecast for the region with milder
temperatures expected for sun and Monday. Hi pressure will settle off the middle
Atlantic and southeast CST for Sat into Monday. A backdoor front will drop across
the area Monday afternoon/night with some cloudiness and maybe isolated precipitation.
The center of hi pressure will build across New England on Tuesday. Maximum temperatures
will be in the upper 40s to middle 50s Sat...in the lower to middle 60s
sun and Monday...and in the upper 40s to upper 50s Tuesday. Min temperatures will
be in the middle 20s to middle 30s Sat morng...in the upper 30s to lower 40s
sun morng...in the 40s Monday morng...and in the middle 30s to middle 40s
Aviation /09z Wednesday through Sunday/...
low pressure moving up the coast will bring a decent slug of
precipitation to the local area overnight and Wednesday. Ceilings
will lower to IFR/LIFR overnight through much of Wednesday at all
taf sites. Colder air wrapping around the coastal low may allow
for a brief period of -rasn Wednesday afternoon/evening northwest of kric.
Gusty north-northwest winds develop later this morning and average
10-20kt with higher gusts of 25-35kt likely at the immediate
coast. Winds are expected to diminish from west to east through
A brief reprieve in adverse conditions should be anticipated late
Wednesday evening and overnight...however a secondary low pressure system
should bring another round of precipitation to the area early
Thursday morning through early afternoon before moving off the coast
and dissipating. Colder temperatures in place will support a little better
chance for -sn or -rasn along and northwest of a general line from ksby-
kric-kfvx. Visibilities should improve much faster than ceilings...which
are then expected to improve/lift/break-up by Thursday evening.
low pressure will intensify as it moves north along the middle-Atlantic
coast from late this morning into the afternoon. Based on current
trends and model guidance...gale force gusts appear likely over all
waters but the rivers today...so have added the remaining Middle Bay
zones to the Gale Warning. Gusts may reach 40 knots on the coastal
waters. Strong sca's remain in place for the rivers through 5 PM.
Winds NE early this morning will switch to northwest this afternoon...as the
system lifts north of the area into tonight. The longer trajectory over
the water this morning should allow seas to build to between 6-10 feet
(highest out near 20 nm).
Sca's will likely replace the gales for a time this evening and
tonight...as the low quickly moves NE and away from the area. A
brief lull in winds Thursday morning before yet another cold air advection surge seen
Thursday evening into Friday morning behind upper level low that exits off the CST.
High pressure builds over the area Friday aftn/night.
a coastal flood statement remains in effect for Maryland/Virginia zones adjacent
to the Atlantic waters and the Lower Bay due to strong north-northeast flow Wednesday
morning leading to water levels within a few tenths of minor
flooding thresholds during the late morning/early afternoon high tide
cycle. Rainfall amounts to 1.50" to 2.50" will also tend to
exacerbate the flooding to some extent. Will continue to monitor
closely and a coastal Flood Advisory will be issued if conditions
warrant. Anomalies should fall off rather quickly later Wednesday/Wednesday
night as winds turn northwest/offshore so do not expect any additional
Marine...Small Craft Advisory until 5 PM EST this afternoon for
Gale Warning until 5 PM EST this afternoon for anz632>634.
Small Craft Advisory until 10 PM EST this evening for anz630-
Gale Warning until 7 PM EST this evening for anz654-656-658.
Gale Warning until 10 PM EST this evening for anz650-652.