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Area forecast discussion 
National Weather Service Mount Holly New Jersey
424 PM EST Monday Feb 8 2016

Synopsis...
strong low pressure well off the East Coast will coninue to move
away from the area this evening. Another weaker low pressure is
forecast to develop off the middle- Atlantic coast overnight. Low
pressure at the surface and aloft will persist over the region
through Tuesday night bringing periods of snow to the area. The
low pressure will gradually move away on Wednesday followed by
colder air and below normal temperatures for Thursday and Friday.
An Arctic cold front on Friday night or Saturday will usher in
perhaps the coldest air of the winter for next weekend.

&&

Near term /until 6 am Tuesday morning/...
Winter Storm Warning and winter weather advisories have been
issued for portions of the area.

As the first strong low pressure system continues to pull away from
the area tonight, another is expected to develop and strengthen off
the coast tonight, which will help lead to an accumulating snowfall.
An area of low pressure is currently located across the eastern
Great Lakes region, with a frontal boundary extending south toward
the Gulf Coast. An area of low pressure is expected to develop along
this boundary overnight, before moving offshore toward daybreak. The
front will weaken and stretch out into more of a surface trough
overnight. Meanwhile, a couple of short wave/vorticity impulses will
slide across the area within the southwest flow. The associated lift
from the surface trough and vorticity impulses, combined with
increasing moisture in the dendritic zone will lead to developing
snowfall this evening and overnight. The heaviest snowfall is
expected to be across southeastern Pennsylvania, southern New
Jersey, as well as northern and central Delaware-Maryland-Virginia where 1 to 3 inches
could fall through daybreak.

&&

Short term /6 am Tuesday morning through 6 PM Tuesday/...
snow is expected to be ongoing at the start of Tuesday as the
surface trough will remain in place across our area as the coastal
low continues to lift to the northeast. The combined lift from the
surface trough, along with a stronger vorticity impulse expected
during the day, will continue to combine with enhanced moisture in
the dendritic zone and is expected to lead to a period of enhanced
snowfall during the day across the area. It may not snow the
entire time during the day Tuesday, but when it does snow, there
could be a few heavier periods. An additional 1 to 3 inches could
fall across portions of the area. Across the southern areas,
snowfall cold change over and/or mix with rain at times during the
day which would limit their accumulations during the day.

&&

Long term /Tuesday night through Monday/...
a deep upper trough/low will move slowly eastward from the Midwest
across the northeast and middle Atlantic regions over the next 2-3
days. This will result in periods of snow across the forecast area
for much of this time. The snow event will be in progress over the
area at the beginning of this extended period...Tuesday evening...although
it looks like the majority of the snow may have already fallen by
that time. This upper system is fairly complex with a number of
shortwave/vorticity centers rotating around it so it is somewhat difficult to
say quite when and where the heavier snow will fall. Overall this
does not look to be a major storm with no strong surface low
development and mainly just light or moderate snow at times...as
noted above. For total snow...most guidance including wpc seemed
to indicate a west-east band of greater snowfall across the middle
of our forecast area and that is reflected in our total snow grid.

The snow should have mostly ended by early Wednesday morning...however
the upper trough will remain over the area during the day on Wednesday so
scattered snow showers will remain a possibility. There will be
decent cold advection behind the system from late Wednesday into
Friday resulting in temperatures well below normal toward the end of the
week. However even colder Arctic air will push into the area on
Saturday with some of the coldest temperatures of the winter expected at
that time. This period is expected to be mostly dry however there
could be snow showers or squalls with the Arctic frontal passage.

&&

Aviation /20z Monday through Saturday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.

VFR conditions continue across the taf sites this afternoon,
although there are some MVFR ceilings at other sites. We expect
conditions to lower into this evening, with everyone becoming MVFR
after sunset. Conditions will further deteriorate through the night
as ceilings are expected to lower to IFR, and snow develops and moves
into the area. Visibilities should drop once snow starts and lower into the
IFR range through the night. Snow may become heavier toward
daybreak, and also during the day Tuesday, so we have lower
ceilings/visibilities during this time.

Winds will remain northeast to east through the entire taf period.
Gusts have dropped off, but a steady 5-10 knot flow should remain.
Winds could become gusty for the Delaware valley tafs south and
eastward toward the coast during the day Tuesday with gusts around
20 knots possible.



Outlook...
Tuesday night...periods of snow expected Tuesday night but tapering
off to snow showers Wednesday morning. Expect widespread MVFR/IFR conds
and the possibility for LIFR if the heavier snow bands develop.
Light winds.

Wednesday...leftover snow showers will taper off from west to east
during the day, with conditions improving to VFR. Breezy westerly
winds gusting to 25 knots.

Thursday and Friday...VFR and breezy northwest winds gusting 20 to 30 knots.

Saturday...possible brief MVFR or IFR conds in snow showers winds
becoming northwest and gusting to 30 knots or greater.

&&

Marine...
outlook... Tuesday night through Thursday...small craft conditions
expected to continue through the period with gales possible on
Thursday.

Friday...sub Small Craft Advisory condtions expected.

Saturday...winds/seas increasing again to Small Craft Advisory and possibly gale
conditions.

&&

Tides/coastal flooding...

Tonight's high tide...
with renewed northeast flow and wave action, widespread moderate
coastal flooding is expected along the Delaware and New Jersey oceanfront during
the high tide around 700 PM to 8pm this evening, in spite of the
lower astronomical tide. For Delaware Bay, where high tide is
between 11pm and midnight, expect minor flooding with pockets of
moderate flooding, particularly with residual high water levels
and ekman transport. Thus, a coastal Flood Warning is in effect
for the entire Delaware and New Jersey oceanfront, as well as Delaware Bay.
Minor nuisance flooding is also possible for tidal sections of the
Delaware River and its tidal tributaries when high tide occurs
around 2 am Tuesday, including Philadelphia, where a coastal Flood
Advisory is in effect.

Overall, for the Delaware and New Jersey oceanfront, we expect similar flooding
tonight, compared to Monday morning's high tide. For Delaware Bay,
we expect greater flooding tonight compared to Monday morning's
high tide with widespread minor flooding and pockets of moderate
flooding.

Tuesday morning's high tide...
with a stronger northeast flow and higher wave action, widespread
moderate coastal flooding with pockets of major coastal flooding
is expected along the Delaware and New Jersey oceanfront during the time of high
tide around 730 am to 830 am. For Delaware Bay, there is a higher
likelihood of moderate flooding near the time of high tide between
11 am and 12 PM. The coastal Flood Warning continues for the entire
Delaware and New Jersey oceanfront and Delaware Bay for the Tuesday morning high
tide. We also expect minor flooding for tidal sections of the
Delaware River and its tidal tributaries when high tide occurs
around 2 PM Tuesday, including Philadelphia, where a coastal Flood
Advisory continues.

Overall, for the Delaware and New Jersey oceanfront, including Delaware Bay,
we expect the greatest impact with the high tide Tuesday morning
compared with the previous two high tides. In fact, there will be
more widespread Road flooding with Road closures in some areas.
There will also be the possibility of damage to more vulnerable
structures, especially factoring in nearshore waves of 5 to 10 feet,
which could also result in significant beach erosion. In particular,
some beach areas will be more susceptible to damage due to beach
erosion and damage to shore structures that occurred in late January,
with emphasis on Cape May County New Jersey and the Delaware oceanfront.

&&

Phi watches/warnings/advisories...
PA...Winter Weather Advisory from midnight tonight to 6 am EST
Wednesday for paz060-061-103-105.
Winter Storm Warning from midnight tonight to 6 am EST
Wednesday for paz070-071-101-102-104-106.
Coastal Flood Advisory until 6 PM EST Tuesday for paz070-071-
106.
New Jersey...Winter Weather Advisory from midnight tonight to 6 am EST
Wednesday for njz009-010-012>015.
Coastal Flood Warning until noon EST Tuesday for njz012>014-
020>027.
Winter Storm Warning from midnight tonight to 6 am EST
Wednesday for njz016>025-027.
Coastal Flood Warning until 4 PM EST Tuesday for njz016.
Coastal Flood Advisory until 6 PM EST Tuesday for njz015-
017>019.
Delaware...Winter Weather Advisory from midnight tonight to 6 am EST
Wednesday for dez003-004.
Coastal Flood Warning until noon EST Tuesday for dez002>004.
Winter Storm Warning from midnight tonight to 6 am EST
Wednesday for dez001-002.
Coastal Flood Warning until 4 PM EST Tuesday for dez001.
Maryland...Winter Weather Advisory from midnight tonight to 6 am EST
Wednesday for mdz019-020.
Winter Storm Warning from midnight tonight to 6 am EST
Wednesday for mdz008-012-015.
Marine...Small Craft Advisory until 6 am EST Wednesday for anz450>455.

&&

$$
Synopsis...amc
near term...Robertson
short term...Robertson
long term...amc
aviation...amc/Robertson
marine...amc/Robertson
tides/coastal flooding...lf

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