Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Wakefield Virginia
336 am EDT Thu Mar 23 2017
high pressure prevails over the region today, sliding offshore
tonight through Saturday. A gradual warming trend begins Friday
into the upcoming weekend. Low pressure tracks across the region
early next week.
Near term /through tonight/...
a cool and dry morning is observed across the region thanks to
a ~1033mb high centered over the northern mid-Atlantic region. A
shortwave digging down the backside of the exiting upper trough
has resulted in a few high clouds over the region, but little
impact to radiational cooling. Temps will start the morning in
the 20's inland to low 30's across southeast Virginia/northeast
High pressure settles over the region today as a broad
anomalous upper ridge over the central US builds eastward.
Despite moderating heights and low level thicknesses, a light
onshore flow and limited mixing will keep temperatures below
normal. Highs struggle into the low to mid 40's along the coast,
and into the low 50's inland. Otherwise, a clear sky prevails.
High pressure slides offshore tonight as winds become south to
southwest. Dewpoints begin to moderate overnight thanks to
modest return flow, but still cool with lows in the upper 20's
to low 30's inland. Cooler over the Maryland Eastern Shore as
temperatures drop quickly into the mid 20's late this evening,
before light return flow warms temperatures into the low 30's
Short term /Friday through Saturday/...
upper flow flattens Friday as an upper level low tracks into
the Central Plains. High pressure slides farther offshore,
resulting in increasing return flow over the forecast area.
Southwest winds increase to 15-20 mph with gusts of 25 to 30
mph. 850mb temperatures warm to around +6 to +8c (~1 Standard
deviation). Have trended toward the warmest guidance Friday as
thicknesses depict temperatures warming into the mid 60's. A
shortwave tracking across the northern mid-Atlantic region will
result in a partly cloudy sky, mostly across the northern half
of the local area. Breezy southwest winds Friday afternoon mix
dewpoints into the low to mid 30's Friday afternoon, resulting
in minimum relative humidity values as low as 30%. Mild Friday
night as light return flow continues ahead of an approaching
storm system. Lows generally in the upper 40's to low 50's.
The upper low begins to weaken/fill Saturday, tracking into the
lower Missouri River valley late. Associated area of low
pressure also locates in the vicinity of northeast Missouri. A
warm front will extend eastward over the northern mid-Atlantic
region as the cold front tracks into the lower Mississippi River
valley. The result will be ongoing return flow over the local
area. 850mb high pressure centers slides offshore, with better
moisture return expected, but conditions remain dry thanks to
ridging aloft (warm temperatures and a lack of forcing). Warm,
with highs in the mid to possibly upper 70's under a generally
partly cloudy sky.
Long term /Saturday night through Wednesday/...
medium range of the forecast period characterized by near to
above normal temperatures, courtesy of arriving mid-level
ridging aloft, and surface high pressure oriented just off the
mid Atlantic/southeast coast. Main weather features of note will
be a series of mid/upper level troughs...bringing a few periods
of scattered light precipitation over the weekend/early next
week. The first of these disturbances traverses across the
central/Southern Plains on Saturday, dampening as it crosses
east-NE into the Ohio Valley and Great Lakes on Sunday and into the
northeast on Monday. This feature will allow for some isolated
to scattered showers Sunday afternoon into early on Monday. Quantitative precipitation forecast
will be limited with this feature. Instability and weakening
dynamics/forcing remain maximized well off to our north-NW, and will
therefore maintain 40-60% pop over our western/northwest tier for some
sct to numerous showers Sunday evening into Monday morning, with
lesser pops for more isolated showers across the southeast coastal
plain. Mild southerly flow will keep temps mild, with forecast
highs in the upper 50s to 60s Northern Neck and lower Maryland Eastern
Shore...with upper 60s to low 70s inland for the weekend into
early next week.
For the middle of next week...attention turns to a pair of
shortwaves. A second southern stream disturbance is expected to
track east/northeastward from the California coast...across the plains
and mid-south late Sat to early Monday. This system will
continue to weaken as it pushes across the eastern third of the
Continental U.S. Monday through early Tuesday. Meanwhile, a northern stream
system will drop from the Pacific northwest toward the northern plains
early Monday, eventually reaching the Great Lakes by the middle
of next week. Models are still split on the evolution of these
systems. The 12z/22 European model (ecmwf) and 00z ec ensembles remains quicker
to dampen these features with the GFS/gefs a bit stronger/more
amplified. Taking a middle of the Road approach remains the
preference at this point, with the resultant blended solution
allowing for continued mild weather Mon to Wed with at least a
small chance for showers on Tuesday and Tuesday night. Shortwave
ridging rebuilds behind this system for Wednesday. Highs remain
mild through the period, with 50s and 60s over the Northern
Neck of Virginia into MD, with highs well into the 60s to mid 70s
inland. Early morning lows mainly in the 40s to low 50s southern
Aviation /08z Thursday through Monday/...
high pressure/fair weather prevails over the region this
morning. A few high clouds at or above 25k feet above ground level are
streaming over the region, with little aviation impact. Surface
winds generally north to northeast at or below 10 knots. Sky clear
conditions expected today as high pressure settles over the
region. Winds become south to southeast this afternoon,
remaining at or below 10 knots.
Outlook...high pressure/fair weather prevails through Saturday.
A storm system approaches from the west on Sunday, with a good
chance of showers late Sunday through Monday.
sfc hi pres remains situated from interior New England S into
the mid-Atlantic states. Continuing low end scas into the
early/mid morning hours. The high is slow to drift east and off the
coast by this eve. Expecting north-northeast winds to gradually wane after
through 12-15z/23...then become more east by late today at ligher
Sfc hi pres remains off the coast tonight...W/ winds becoming SW
Fri and lingering through Sat. Speeds increase to 15-20 knots
by Fri afternoon as a storm system develops over the Midwest.
The next front crosses the waters early next week...W/ relatively
benign marine conditions expected over the weekend in south-southwest winds
mainly aob 15 kt. Seas averaging 2-3 ft...waves 1-2 ft.
radar kdox remains inoperable due to a bad spectrum filter.
Maintenance is expected to begin overnight with an estimated
(though possibly unstable) return to service is now Friday,
Marine...Small Craft Advisory until 7 am EDT this morning for
Small Craft Advisory until 1 PM EDT this afternoon for anz656-