Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
909 PM EST Sat Nov 22 2014
high pressure will slide off the middle Atlantic coast tonight and
moves farther offshore Sunday. A warm front will lift north across
the region late Sunday afternoon through Sunday night. A cold front
will cross the area late Monday into Monday night. Weak high
pressure builds into the area from the west Tuesday. Low pressure
tracks up the East Coast Tuesday night and Wednesday.
Near term /until 6 am Sunday morning/...
latest GOES WV imagery indicates a potent trough tracking across
Texas...with a broad ridge downstream covering the southeast and Middle
Atlantic States. At the surface...a ~1030mb high is centered just
offshore of the NC Outer Banks. Infrared satellite imagery showing some
middle level cloudiness across the southeast into the Carolinas out
ahead of the trough moving across the Texarkana region overnight
toward the central Gulf Coast. Temperatures have fallen off
quickly into the 30s as expected early this evening with light
winds/clear sky and with dry airmass in place. Temperatures should
begin to stabilize over the next few hours...becoming steady or
even slowly rise late tonight into early Sunday morning as clouds
gradually increase and lower towards morning. Nudged inherited
minima down slightly given latest observation...but still anticipating
u20s to l30s inland...middle to upper 30s along the coast.
Short term /6 am Sunday morning through Tuesday/...
clouds continue to increase...thicken...and lower from the SW sun
as Gulf Coast moisture and an associated warm front lift NE through
the southeast Continental U.S....ahead of the middle-level trough lifting through the
Tennessee Valley. Much of the day should be dry...but some rain
should arrive in SW portions late in the day...with 60% probability of precipitation SW
late in the day...bordered by a 30-50% pop from the northwest Piedmont
through NE NC. Highs should range from the middle 50s northwest to low 60s
The warm front with strong vertical motion will cross the middle
Atlantic region primarily from sun evening through the early
overnight hours. Substantial moisture (+3 St dev precipitable water 03-06z Monday per
22/15z sref) will accompany the front due to a strong nearly 70kt
low level jet. Probability of precipitation for rain during the 12hr period Sun night have been
raised to 100%. A slight chance of thunder will be maintained for
coastal NE NC. However...0-3km lapse rates seem to be a limiting
factor throughout the 22/12z suite of numerical guidance...offsetting
a strong ambient wind field. Given this...the Storm Prediction Center slight risk has
been shunted S of the Albemarle Sound. A tightening pressure
gradient and 6hr pressure falls of -7mb to -10mb per 22/12z GFS
will result in breezy/windy conditions...especially in vicinity of
the coast. Gusts from the south-southeast direction of 30 to 40 miles per hour are
possible. Lows Sun night should range through the 50s...with
readings likely to rise after midnight. Strong forcing and
substantial moisture should result in a ~6hr period of moderate to
occasionally heavy rain Sun night...with total quantitative precipitation forecast amounts
The warm front will be well north-northeast of the region by 12z Monday...with a
cold front approaching toward the far western counties by 00z Tuesday. Low
clouds and fog are possible Monday morning...with a gusty SW wind
developing during the late morning and afternoon in advance of the
cold front. This will help push temperatures into the 70s (see the
the climatology section below for records). 22/12z NAM lingers moisture
across the area. This is somewhat of an outlier at this time.
However...probability of precipitation have been increased to 20-30% due to the approach
of the cold front and secondary shortwave trough.
Weak high pressure builds into the region Monday night and Tuesday. Partial
clearing is possible inland...with clouds lingering near the coast
as the frontal boundary stalls offshore and low pressure begins to
develop off the southeast coast later Tuesday. Highs Tuesday should range
from the middle 50s northwest...to low 60s southeast...after morning lows from the
middle 40s northwest...to low/middle 50s southeast.
Long term /Tuesday night through Saturday/...
going with a blend of the 12z GFS and 12z European model (ecmwf) for the extended
period. Models now showing southern stream low pressure over the eastern Gulf Tuesday
eveng...will track north-northeast and just off the east CST Tuesday night into Wednesday
night. Thus...have increased probability of precipitation for rain to 40%-60% (highest in the
eastern half of the region) during Wednesday. Precipitation/moist then moves east of the
area and off the CST later Wednesday eveng/Wednesday night...with probability of precipitation diminishing
from west to east. A mainly dry front swings across the area Thursday afternoon into
early Friday morng. Hi pressure will then build into and over the region Friday
through Sat. Maximum temperatures will be in the 40s Wednesday...in the upper 40s to lower
50s Thursday...in the middle to upper 40s Friday...and range through the 40s Sat.
Min temperatures will be in the middle 30s to lower 40s Wednesday morng...in the upper
20s to middle 30s Thursday and Friday morngs...and in the middle 20s to lower 30s
Aviation /02z Sunday through Thursday/...
VFR conditions continue across the region and will persist into Sun
morning. Surface high pressure has moved offshore of Virginia/NC and winds
around the high are southeast-SW over the region and generally less than
10 kts. Meanwhile...lots of moisture across the southeast and Gulf states
will push north into the middle atl region during the overnight and
A middle-level wave will help form a surface low pressure system
across the southeast US as the middle-level wave moves NE out of the Gomex
on sun. This will further increase the moisture as a warm front
surges through the area Sun night. Expect IFR conditions(possibly
lower) due to lowered ceilings and reduced visible due to rain.
Also...wind gust to 35kt may be possible Monday morning as the system
deepens over the area. Elevated thunderstorms will also be
possible over NE NC/southeast Virginia.
have hoisted sca's for the entire waters starting sun eveng...and
lasting through Monday afternoon/eveng or Monday night for the ches Bay/Currituck
sand and the coastal waters. Hi pressure slides out to sea during sun...with
low pressure moving from the middle MS Valley North-northeast through the Great Lakes and
into eastern Canada sun eveng into Monday night. Southeast or S winds will
increase across the waters/region late sun into Monday morng in advance
of a cold front. Southeast or S winds 15 to 25 knots with gusts up to/around
30 knots expected sun eveng into Monday eveng...with waves bldng to 3
to 5 feet in the ches Bay...and seas bldng to 5 to 8 feet on the
coastal waters. Cold front crosses the waters Monday night...with calmer
conditions expected Tuesday into Tuesday night. Strong NE or north winds then
expected Wednesday into Wednesday night...as low pressure tracks nwrd just off the
unseasonably warm weather expected Monday.
Record high temperatures for Monday.
Ric 76 1979
orf 78 1983
sby 78 1931
ecg 77 1983
Marine...Small Craft Advisory from 10 PM Sunday to 10 am EST Monday for
Small Craft Advisory from 10 PM Sunday to 7 PM EST Monday for
Small Craft Advisory from 10 PM Sunday to 4 PM EST Monday for
Small Craft Advisory from 10 PM Sunday to 1 am EST Tuesday for
Small Craft Advisory from 10 PM Sunday to 4 am EST Tuesday for