Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
1156 PM EST Sat Feb 28 2015
Arctic high pressure remains over the region through
tonight...then slides offshore Sunday. Low pressure tracks
northwest of the area Sunday and Sunday night. The trailing cold
front pushes across the region Monday morning.
Near term /through Sunday/...
have extended the winter weather adsy another tier of counties per
latest observation with dew points still in the teens and temperatures in the
20s...with some additional cooling expected over the next few hours
as skies become mostly clear.
Strong (~1044 mb surface hi pressure centered over eastern sections of the County Warning Area
this evening providing cold/dry conditions over the region.
Variably cloudy skies currently...though with a period of mainly
clear skies likely over the next few hours per latest satellite.
This should allow temperatures to drop off a few more degrees...with lows
in the teens on the Eastern Shore...and 20-25 across most of the rest of
the County Warning Area (locally warmer 25-30 f in NE NC and far southeast va).
Between 06-09z...zonal flow aloft will bring increasing moisture
from the Ohio/Tennessee Valley with increasing low level moisture being
transported north from SC as 800 mb to h9 winds veer to the south-southeast.
Temperatures may rise slightly late as cloudiness increases/ceilings
gradually lower. Some light precipitation will try to spread into far west and SW
portions of forecast area (piedmont west of I 95) after 10z/01. Partial
thicknesses suggest ptntl mixed p-type (sn- ice pellets to start...then ice pellets-
fzra)...W/ temperatures in the M/u20s. Have raised a Winter Weather Advisory for
far western portions of forecast area...beginning at 09z/01.
Surface low pressure ejects NE from Ohio Valley to western new eng sun west/ assctd
warm front lifting northward across the forecast area. Surface hi pressure and low level
cold air will be slo to retreat during the day...setting up ptntl
winter p-type event lingering into the afternoon (esp away from the cst).
Model thermal profiles and climatology suggest that highest probability for ice
accums of 0.1" or greater will be west and northwest of ric...though will
continue to mention possible light mixed precipitation as far east as a
line from about sby- akq- emv line. East of that line...expecting mainly rain
as temperatures rise sufficiently above freezing before precipitation arrives...reaching
the l/m40s right at the CST...upper 30s not that far inland. To the
west...will hang onto to the Winter Weather Advisory until 21z/01-00z/02
for mainly ice accums up to tenth of an inch. Hi temperatures far west-northwest
struggle to rise into the l30s in the afternoon...l/m30s expected across
central tier from avc/emv to interior lower Maryland Eastern Shore.
Short term /Sunday night through Tuesday/...
precipitation tapering off well inland to freezing drizzle or drizzle Sun
night...while will have chance to likely probability of precipitation central and east. Temperatures hold
nearly steady from the 30s to l40s.
Cold front crosses the forecast area Monday morning...to be followed by clearing
and drying west-northwest winds. Have hung onto to slight chance/low chance probability of precipitation near the
CST Monday morning however. Hi temperatures from the m40s on the Eastern Shore areas
Surface hi pressure settles over the forecast area Monday night...though cloudiness will be
quickly returning as flow aloft becomes west-southwest. Another round of precipitation
(primarily rain...though brief mix possible across far interior portions
of forecast area Tuesday mrng) expected on Tuesday. Low temperatures Monday night from the l20s north to
u20s S. Hi temperatures Tuesday from the l/m40s north and west to the u40s/around 50f southeast.
Long term /Tuesday night through Saturday/...
surface pressure gradient tightens Tuesday night as low pressure to the
north pushes a cold front toward the middle Atlantic region. Light southeast
winds become southwesterly and breezy overnight which will promote warm air
advection...increasing dewpoints...and rising temperatures during
this time. Temperatures should have no problem rising into the
middle-upper 60s before rain moves in from the west with the front Wednesday
aftn/evening. Far southeast areas may reach 70 degrees...whereas far northern
areas may only top out in the lower 60s for highs. Precipitation will be in
the form of all rain Wednesday/Wednesday evening. Far northern areas may see a
rain/snow mix after midnight night Wednesday night...possibly changing to
snow by Thursday morning as a broad area of high pressure builds north of
the middle Atlantic region thus bringing a return to a colder airmass
and low temperatures near freezing north of Richmond.
Thursday may result in a tricky forecast as an upper trough swings
through the Ohio Valley and across the middle Atlantic region Thursday
night. Any moisture associated with this shortwave energy will
stream across the area and ultimately run into remnant warmer air
across the southeast...thus producing light showers. Model quantitative precipitation forecast
supports this continuation of precipitation through Thursday and then tapering
off from west to east Thursday night. A decent jet streak around 170kt
will also enhance lifting potential and aid precip-generation. Highs
on Thursday expected to be in the 40s (lower 50s along Albemarle
Sound...upper 30s Maryland lower eastern shore) with dewpoints falling
below freezing from northwest to southeast through the day. This supports mainly
rain on Thursday with a rain/snow mix north of Richmond. As temperatures
drop into the upper teens northwest to middle-upper 20s southeast Thursday night...precipitation
transitions to all snow. With another round of modified Arctic air
moving into the area...quantitative precipitation forecast amounts are rather bullish. It is too
soon to nail down specific snowfall accumulation amounts but suspect
that they would be light. High pressure moves overhead on Friday and
all precipitation comes to an end. Cool and stable conditions should keep
high temperatures Friday in the upper 30s (lower 30s Northern Neck and Maryland/Virginia
eastern shore). Westerly flow aloft starts to modify 850 temperatures Friday night
into the upcoming weekend. Highs rebound into the middle-upper 40s for
Aviation /06z Sunday through Thursday/...
VFR conditions continue tonight with clouds increasing. Cold
surface high pressure centered over of the County Warning Area will slide east
tonight. A weak disturbance over the southeast states will move north
overnight and bring precipitation with it. Due to the cold NE flow at the
surface and warming S-SW flow aloft...there will be a chance of -fzra
for portions of the County Warning Area Sun morning into early afternoon...especially west
of i95. A brief wintry mix may also affect sby/phf/orf during the
morning and early afternoon before changing over to all rain. Ceilings are
expected to lower to MVFR conds by middle morning for ric...then move
east as the precipitation overspreads the region. Expect IFR conditions
as ceilings continue to lower Sunday afternoon across the area.
Precipitation ends Sun night. A cold front passes through the region
Monday morning with high pressure building in from the west and
dry weather returning.
seas have finally dropped to 3-4ft with high pressure building over
the waters this evening. Seas will continue falling to 2-3ft after
Light NE/onshore winds at or below 10kt will persist through the first half
of Sunday until high pressure moves well offshore with an
approaching cold front. As the cold front advances toward the waters
during the second half of Sunday into Sunday night...winds shift
to the SW and start to increase after midnight Sunday night but
stay below Small Craft Advisory thresholds. The cold front pushes across the waters
Monday morning...followed by a brief northerly surge right behind
the front. A brief period of low-end Small Craft Advisory winds may be possible but
waves/seas should remain below Small Craft Advisory thresholds. High pressure
returns to the area Monday night into Tuesday with generally quiet
conditions and light NE to east winds expected. Low pressure tracks
just north of New York state late Tuesday night and into the
Canadian Maritimes on Wednesday...dragging a cold front across the
waters Wednesday aftn/evening. Winds become S to SW and increase
to Small Craft Advisory speeds late Tuesday night into Wednesday. Seas build to 4-7ft and
waves build to 3-4ft during this timeframe. Small Craft Advisory conditions diminish
Wednesday night as high pressure builds toward the middle Atlantic region
through the first half of the upcoming weekend.
records at Richmond and Norfolk date back into the late
1800s...with some notable top ten ranks in snow and temperature
Average temperature for February 2015:
Richmond: 31.4 f (-9.5 from avg). 6th coldest Feb on record and
the coldest since 1979.
Norfolk: 32.5 f (-10.0 from avg). 3rd coldest Feb on record and the
coldest since 1934.
Snowfall for February 2015:
* richmond: 12.2" (snowiest Feb occurred in 1983 with 21.4"). This
moves Richmond up to #9 all time for Feb.
* Norfolk: 11.5" (snowiest Feb occurred in 1989 with 24.4"). This
moves Norfolk up to #7 all time for Feb.
Record low temperatures (sunday morning):
3/1 all time record low temperatures for March
ric11/1937 10 March 4 2009
orf18/1980 14 March 14 1888
sby 13/1980 1 March 3,4 2009 and March 9 1911
ecg 16/1937 16 March 1 1937 and March 4 1943
Virginia...Winter Weather Advisory from 4 am to 7 PM EST Sunday for
Winter Weather Advisory from 4 am to 4 PM EST Sunday for