Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
614 am EDT Monday Mar 17 2014
low pressure intensifies as it tracks to off the Carolina coast
today. A second area of low pressure lingers off the southeast
coast tonight and Tuesday. High pressure builds across the
southern states for the middle week period.
Near term /until 6 PM this evening/...
based on current radar / surface temperatures & p-types...will keep current
warnings / advsrys in place mainly due to impact and for second
batch of precipitation moving east from the mts. Less than an inch addntl
accumls expeceted. Day shift can re-evaluate headlines in a few hours
once the sun comes up.
appears high pressure to the north just not strong enough to hold
enough cold air in place for a widespread snow across the area
with the exception of northern most countys (2-4 inches as of this
writing). Local studies indct 1020 mb or higher isotherm needed
across akq forecast area for The Wedge to have the most impact. Msas showing
only 1016 mb across the area at this time. Thus...the circulation around
the low to the south has allowed a bit warmer air to come in aloft
(arnd 2c at h8) for a mixed bag of precipitation across the area overnight.
Add to this a dry slot that has cut off the significant quantitative precipitation forecast over
the south and all this results in a much weaker impact event than
was anticipated. Guess we got lucky for St patricks day.
Models agree that best forcing rapidly lifts north of the area by
12z as coastal low takes over as primary feature. However...plnty of
low level moisture prognosticated to keep a mixed bag of p-types going
today...with the majority of the precipitation during the morning hours.
Tsctns / soundings indct more of a lght precipitation / drizzle this afternoon.
Addntl accumulations aftr 12z to be less than 1 inch across northern most
countys. Kept current warnings / advsrys going for more of an impact
due to the mixed p-types today. Just rain/drizzle across southern third
of the forecast area. Dryer air from the north will end the precipitation across northern
areas late in the day. Will have a shot of breaking some record
low maximum temperatures for 3/17. Combo of a raw north-NE wind...clouds and precipitation
keeps maximum readings about 2 stndrd deviations below normal. Highs
in the 30s...xcpt l40s southeastern areas.
Short term /6 PM this evening through Tuesday night/...
models in general agreement with the handling of the second low
pressure systm tonight and Tuesday. BUFKIT soundings continue to show
substantial dry air in the dendritic growth zone (-10 to -20c) so
expecting mostly just drizzle or very light precipitation after midnight.
Enough of a warm nose above 850-900 mb that the ptype outside of
far southeast Virginia/NE NC would be either freezing rain/drizzle or sleet.
May eventually need anthr winter weather adsy for portions of the County Warning Area and
will mention in severe weather potential statement for now.
Moisture from this low prognosticated to drift back north across the region
Tuesday. Tuff to tell just when the measurable precipitation begins across
the west but for now will keep the chance probability of precipitation going over most of the
forecast area...likely probability of precipitation across southeastern areas where deepest moisture prognosticated.
P-type here mainly rain...however some freezing rain / drizzle possible
across Piedmont areas in the morning. Unseasonably cold again with
highs in the 40s (one Standard deviation below normal).
Generally dry Tuesday night as weak upper ridge builds in along the East
Coast...but light low level onshore flow should keep skies mainly
overcast. Continued dreary on Wednesday despite winds slowly shifting to the
S/se. Could see some sunshine by afternoon but confidence not that high.
Somewhat warmer...but still went a few degrees cooler than guidance.
Highs in the 50s.
Long term /Wednesday through Sunday/...
a change to drier and milder weather can be expected during the
latter part of the week. Temperatures then drop to below normal by
Sunday. Precipitation is possible with the cold front around Saturday.
As the shortwave trough exits the region Wednesday...the dominant
upper flow across much of the Continental U.S. Becomes fast and almost zonal.
Thursday and Friday will feature slightly above normal
temperatures. Upper level heights gradually lower and a cold front
drops through the Middle Atlantic States Saturday...bringing a return
to below normal temperatures by Sunday. There is a chance for
showers with the cold front Saturday.
High temperatures Thursday range from the 50s on the lower Eastern
Shore to the lower 60s across most inland areas. Highs on Friday
and Saturday are expected to be from the upper 50s to around 60 on
the lower Eastern Shore to the upper 60s over inland southern
Virginia. Highs on Sunday cool to 50 at the coast to the middle and
upper 50s inland. Lows around 40 Thursday morning lower to the 30s
Friday morning...increase to the 40s on Saturday morning then fall
back to the 30s Sunday morning.
Aviation /10z Monday through Friday/...
low pressure develops off the NC coast and pulls offshore through
the morning hours. Meanwhile...high pressure remains anchored north of
the region. Precipitation should prevail as -sn at sby...before
transitioning to more of a wintry mix of -ra/snow or pl between 12-14z
as the intensity diminishes. Ric should mainly be -pl or -sn/pl
through the 12-14z timeframe before transitioning to -ra/sn. Phf
should prevail as -ra. However...occasional periods of pl are
possible in heavier pockets of precipitation. Orf/ecg are expected
to remain as -ra. A 10-15kt NE wind will prevail away from the
coasts...with speeds around 20kt...with gusts to around 30kt along
the coasts. IFR ceilings should prevail through around 14z...and may
lift to MVFR thereafter. Surface high pressure remains anchored
over New England tonight into Tuesday. This will maintain NE flow
and low-level moisture across the region. IFR ceilings are possible
tonight along with pockets of -fzdz inland/-dz along the coasts.
Conditions slowly improve Wednesday ahead of a cold front...which
could bring a few -shra. Dry conditions will prevail Thursday and
a surface low has emerged off the northern Outer Banks early this
morning...and will quickly race well east and out to sea by late
morning. A decent pressure gradient has developed between the
offshore surface low and high pressure over interior New England. As a
result...have seen winds ramp up to gale force across the ocean
waters and much of the central/lower ches Bay. Elsewhere...solid Small Craft Advisory
conditions exist across the rivers of eastern Virginia and the Currituck
Sound. Will leave headlines as-is given current observation...except for
replacing the Gale Warning on the Currituck Sound with an Small Craft Advisory. Winds
are expected to continue at similar speeds through the morning
hours before diminishing slowly this afternoon as the surface low
continues to head east. Should be able to replace gales with sca's
all areas this afternoon. Seas this morning are currently running
from 7-9 feet north to 8-12 feet off the Outer Banks. Only expecting a
slight reduction in seas this afternoon as persistent north-NE flow
Another surface low moves north along the southeast coast on Tuesday...as high
pressure remains north of the region. Small Craft Advisory conditions will persist
through at least early Tuesday evening due to continued onshore flow
and slowly diminishing winds. Seas will take longer to subside and
could stay around 5 feet into Thursday.
a strong NE wind along with a full moon will result in elevated
water levels today. Tidal anomalies are expected to range from
1.5-2.0 feet above normal at high tide this morning for Ocean City.
This will place water levels around 4.0 feet...which is the minor
threshold for Ocean City. A coastal Flood Advisory remain in
effect for this mornings high tide at Ocean City. Tidal anomalies
of 1.5-2.0 feet above normal along the lower Chesapeake Bay and
tidal rivers of far southeast Virginia will place water levels near minor
flooding thresholds later this morning. A coastal flood statement
has been issued to account for this.
record low maximum temperatures for 3/17:
Ric...40 in 1900
orf...38 in 1893
sby...33 in 1916
Maryland...Winter Storm Warning until 5 PM EDT this afternoon for
High surf advisory until 11 am EDT this morning for mdz025.
Coastal Flood Advisory until 11 am EDT this morning for mdz024-
NC...Wind Advisory until 2 PM EDT this afternoon for ncz017-102.
High surf advisory until midnight EDT tonight for ncz102.
Virginia...Winter Weather Advisory until 5 PM EDT this afternoon for
Winter Storm Warning until 5 PM EDT this afternoon for vaz048-
High surf advisory until 2 PM EDT this afternoon for vaz095-
Wind Advisory until 2 PM EDT this afternoon for vaz095-098.
High surf advisory until 11 am EDT this morning for vaz099-100.
Marine...Gale Warning until 2 PM EDT this afternoon for anz630>632-634-
Small Craft Advisory until 1 am EDT Tuesday for anz635>638.
Small Craft Advisory until 8 PM EDT Tuesday for anz633.