Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
952 PM EDT Sat Mar 28 2015
high pressure builds into the region overnight and settles over
the area Sunday. A weak cold front will move across the region
later Sunday night into early Monday...with high pressure
returning Monday afternoon and Tuesday.
Near term /tonight/...
last of the short wave energy (in the form of a scattered-broken ac deck) will
cross the ches Bay / Eastern Shore areas next few hours. Kept it dry
given deep temperatures dropping through the teens...but a stray flurry still
possible across the Eastern Shore next hour or so. Otw...skies clear as high
pressure builds in from the west. January like readings by morning
as winds decouple west of the Bay allowing for good raditional
cooling. Lows in the l-m20s...xcpt u20s along the immediate coasts
of southeast Virginia/NE NC. These readings expeceted to fall just short of the
record lows for 3/29. See cli section below.
Short term /Sunday through Tuesday night/...
surface high pressure will move across the region Sunday. This
will result in dry...sunny...and cool conditions with a light northwest
wind becoming SW by afternoon. Limited mixing will only allow high
temperatures to reach the middle/upper 40s along the coast...to the
low 50s over interior Virginia/NE NC. Have dropped high by a degree or
two based on the guidance...but expect a good deal of sunshine
with some high clouds possibly pushing in from the northwest late in the
An upper level trough and weak surface cold front cross the region
late Sunday night into early Monday morning. Expect increasing
clouds Sunday night along with a chance for rain. With the low-
level airmass starting out so fry and return southerly flow
limited...so there is only a low probability for -shra (~20-30%)
with rain accumulations of only a few hundredths. Many areas will
likely only see a trace of that much. The boundary drops S of the
region early Monday with deep layered west-southwest flow developing Monday.
Mostly cloudy conditions early should give way to a partly to
mostly sunny sky by afternoon. Improved mixing and more sun will
result in highs ranging from the low/middle 60s east...to middle/upper 60s
west. This will be after morning lows in the middle 30s to low 40s.
This trend will continue into Wednesday as high pressure moves
directly across the region. Skies will remain mostly sunny most of
the day with highs remaining near 60 over Eastern Shore and along
the immediate coast and middle to upper 60s inland.
Long term /Wednesday through Saturday/...
better agreement in medium range guidance with respect to handling
split flow compared to 24 hours ago. To begin the extended...good
model consensus now with a northern stream wave dropping into the northern middle-
Atlantic region late Tuesday night. Associated surface low prognosticated to track
across northern Virginia/Maryland Tuesday night with a weak cold front sweeping across
the region early Wednesday morning. Best moisture/lift will be north of
the local area...but will introduce slight chance-low end chance
probability of precipitation across the NE zones late Tuesday night closest to best
moisture/lift. Surface low and cold front push well offshore Wednesday as surface
high pressure centers over the region. Modest cold air advection and mostly sunny
skies will result in temperatures in the low-middle 60s inland and middle-upper
50s Eastern Shore and coastal areas. High pressure pushes offshore Wednesday
night-Thursday as a southern stream wave lifts from the Southern Plains into the
Tennessee Valley. Moisture return expected thanks to increasing S-southeast flow.
28/12z European model (ecmwf) quicker with bringing precipitation into the region Thursday
afternoon. Have dropped probability of precipitation Thursday afternoon...but kept slight
chance probability of precipitation across the Piedmont. South-southwest flow will help moderate temperatures
into the upper 60s to around 70 inland to low-middle 60s coastal areas
Thursday. Expect clouds to increase Thursday afternoon.
Thereafter...chance for precipitation ramp up Thursday night-Friday as the southern
stream wave lifts over the region. Northern stream wave over the upper
Midwest also prognosticated to flatten and track across the Great Lakes
region late Thursday-Thursday night. Associated occluded surface low locates
over southeastern Canada Thursday night-Friday morning...with an attendant cold
front crossing the region during the Friday-Sat timeframe. Spatial and
timing differences exist...but will carry chance probability of precipitation through Sat
morning. Slight warmer Friday with highs in the low-middle 70s inland and
low-middle 60s coastal areas.
Aviation /02z Sunday through Thursday/...
VFR conditions expected through the 00z taf period. Deep upper
trough will slide off the coast tonight with high pressure
building over the region Sunday. Few cumulus due to cold air at around
6k feet. This cloud layer should clear after sunset as surface
heating ends. Northwest winds will diminish slightly overnight with some
increase in the winds once again during the day Sunday.
Outlook...the aforementioned high will move to the south Sunday
night as a weak cold front crosses the area early Monday. There
will be slight to low chance for showers early Monday. High pressure
builds back into the area early next week. A chance for showers
latest surface analysis reveals low pressure lifting well off the middle-
Atlantic coast this afternoon with high pressure centered over the
Midwest. Ongoing cold air advection continues to produce strong northwest winds of 15-25
knots over the water. Waves average 2-4 feet and seas 4-6 feet. Small Craft Advisory conditions
persist through the night thanks to the pressure gradient and cold air advection.
Waves remain 2-4 feet and seas 4-6 feet. High pressure builds SW of the
water early Friday...with northwest winds diminishing at or below 15 knots by middle
morning. Seas subside by early afternoon. High pressure builds south
of the water Sun afternoon...with flow becoming southerly at or below 10 knots late
sun. The next cold front approaches from the west Monday
night...crossing the water late Monday-early Monday night. Prefrontal southerly
surge expected Sun night...with speeds increasing to 15 knots in the
Bay and 20 knots in the coastal waters. Models indicate Small Craft Advisory
conditions...but based on warm air advection and cold water...expect a sharp low
level inversion to prevent strongest winds from mixing to the
water. Have capped speeds below Small Craft Advisory at this time. Southerly fetch may push seas
to 5 feet in the northern coastal waters Monday morning. Southwesterly flow returns
Monday night- Tuesday. Low pressure tracks across the middle-Atlantic
region late Tuesday with another front crossing the water early Wednesday
night. Winds stay at or below 15 knots. High pressure returns weds-thurs.
record low temperatures for Sunday 3/29:
Marine...Small Craft Advisory until 7 am EDT Sunday for anz635>638.
Small Craft Advisory until 10 am EDT Sunday for anz630>634.
Small Craft Advisory until 1 PM EDT Sunday for anz650-652-654-