Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Mount Holly New Jersey
954 PM EDT Friday Mar 14 2014
low pressure will move through the Great Lakes region with a weak
frontal boundary moving through our area during the late overnight
hours. A stronger cold front will push through the region Saturday
afternoon. High pressure builds in briefly for Sunday. Meanwhile,
a low pressure system will develop across the Southern Plains and
will track to the east Sunday into Monday, remaining centered to
our south. High pressure will build in from the north for Tuesday
and Wednesday. Yet another cold front will cross the region on
Near term /until 6 am Saturday morning/...
high pressure just off the Carolina coast will continue to move
east overnight and Saturday. Meanwhile...a weak frontal boundary
associated with a low pressure system moving through southern
Canada will cross the County Warning Area during the late overnight hours. Light
snow, or a rain/snow mix, is possible in the southern Poconos and
northwest New Jersey...and the highest terrain in the Lehigh
Valley and north central New Jersey, with mainly rain showers
elsewhere. Right now the snow grids contain less than one-half
inch of snow accumulation in the southern Poconos and far
northwest New Jersey. Gusty southerly winds this evening will
continue to subside tonight...then become southwest during the
late overnight hours as the weak front passes through. Low
temperatures in the low to middle 30s are expected in the north...and
in the upper 30s south.
Short term /6 am Saturday morning through 6 PM Saturday/...
any snow that falls in the far north will melt on Saturday as
temperatures rise into the low to middle 40s...and into the 50s
everywhere else...perhaps reaching into the low 60s in the far
south. Westerly winds will pick up during the morning hours, gusting
around 20 miles per hour at times. Skies will be mostly sunny, so the day will
turn out nice, especially considering the colder than normal weather
we experienced on Thursday. A cold front will cross the area from
west to east from about middle-day on, reaching the coast by early
evening. This front has very little moisture associated with it, so
no precipitation is expected, but the wind will shift from west to
northwest, and dewpoint temperatures will begin to fall.
Long term /Saturday night through Friday/...
Saturday night...the cold front pushes well offshore, leaving a
boundary extending westward through the southern states. High
pressure will start to nose down from the northwest and we should
have a dry evening on tap. Temperatures will drop in the northwest
flow and we will see them drop into the 20s to lower 30s through
the forecast area.
Sunday and Monday...high pressure will nose down into the area from
the northwest during the day on Sunday. Low pressure will develop
across the Southern Plains and track to the east northeast along
the previously mentioned boundary. The high is not overly strong
but it appears to be just strong enough to help suppress the
approaching low pressure system. For the most part, we should
remain mostly dry across the area through much of the day. Clouds
will increase through the day with precipitation starting to move
in from the south in the late afternoon/early evening and then
gradually spreading northward. Precipitation will gradually spread
northward through Sunday night into Monday and then continue
through the day on Monday before cutting off by Monday night.
The big issue will be timing and where the heaviest axis of
precipitation sets up and whether or not that area will see all or
mostly snow through the event. It looks like the heaviest
precipitation, including the accumulating snow, would most likely
occur during the overnight and early morning hours as the March
sun angle tends to make it much more difficult for snow to
accumulate during the daytime.
The latest model guidance has come in drier than the previous runs.
This leads to thinking that the snow amounts might not be quite as
high as the overnight runs were indicating. Still a lot of spread in
the guidance but and axis of heavier precipitation situated to the south of
phl looks pretty good right now. Snow amounts will be lesser across
the northern parts of our area with the higher amounts looking to be
through the philly metropolitan area and into the Lehigh Valley. Areas to
the south will see more of a mix occur and this will knock down the
snow amounts for them. Not confident on snow amounts but could see
an area of 4 to 6 inches occur. Plenty of time to see what the
models do as they start to Sample the atmosphere better, especially
as the northern stream shortwave has just moved onshore this
Stay tuned for more details as we continue to monitor this upcoming
Tuesday...we get a bit of break on Tuesday as the low moves further
away from the region. We should have a dry day with high
temperatures reaching into the upper 30s to lower 40s through much
of the area.
Wednesday and Thursday... we start off dry but precipitation will
move into the region through the day with the next front pushing
through late Wednesday night into Thursday. Right now it looks like
we will be warm enough for this to be a mostly rain event, with some
snow mixing in across the higher elevations in our northern areas.
Aviation /02z Saturday through Wednesday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.
Gusty southerly winds will gradually subside into the 10 to 15 knots
range overnight, then become more southwest to westerly toward
morning as a frontal boundary moves through. Through most of this
timeframe, low level wind shear of about 50 knots at 2000 feet is
possible, and this is included in the tafs. Some light rain
showers or sprinkles are possible with the boundary, perhaps
mixing with snow for a brief period of time at our northern taf
sites. However, by sunrise most of this precipitation will have
moved out, with clearing skies for the rest of the day. This first
boundary will bring with it a slight wind shift from southwest to
west. A cold front is expected to move through the area from west
to east Saturday afternoon, with no precipitation, but another
wind shift from west to northwest by late in the day. Winds are
also expected to pick up in speed during the morning hours, with
gusts into the 25 to 30 knots range expected for most of the day.
Saturday night and Sunday...mainly VFR conditions are expected.
Sunday night through Monday...VFR will drop to MVFR/IFR conditions
in areas of rain and snow. Snow is more likely from kphl-kilg and
areas to the north and west. Winds will be gusty out of the
northeast around 20 to 30 knots, especially closer to the coast.
Winds will decrease through Monday afternoon and evening.
Tuesday...mainly VFR conditions are expected.
Wednesday...VFR conditions to start the day. Periods of MVFR,
possibly IFR, are possible in rain/snow showers.
a strong southerly flow producing gusts around 25 knots will persist
into the evening hours, then subside somewhat overnight. This flow
is also producing seas in the 4 to 6 foot range. Winds will turn
westerly Saturday morning after a weak frontal boundary moves across
the forecast waters. Gusty winds in the 20 to 25 knots range in advance
of a cold front heading east.
Saturday night through Sunday...sub advisory conditions are
Sunday night through Monday...Small Craft Advisory conditions will
develop through Sunday night and continue through Monday. Gale force
winds are possible on Monday, especially across the southern waters
as low pressure moves along the coast.
Tuesday...Small Craft Advisory conditions should start to subside,
with sub advisory conditions expected by the afternoon.
Wednesday...sub advisory conditions are expected.
minimum relative humidity values are not expected to drop below 30
percent on Saturday, even over the Delaware-Maryland-Virginia region. This combined
with slightly lower wind gusts will help reduce the fire weather
threat on Saturday, so no flags are expected.
the low pressure system slated to affect the region Sunday night through
Monday, combined with northeast winds and in conjunction with the
full moon, may cause some minor tidal flooding to occur along the
Delaware and southern New Jersey coastlines.
begorah, more snowfall records to fall and/or climbing higher in the
snowfall record department:
Daily snowfall records for:
Allentown 12.0 in 1896 4.2 in 1967
Atlantic City 1.7 in 1978 1.6 in 1965
Philadelphia 4.1 in 1978 3.5 in 1892
Wilmington 2.9 in 1978 2.4 in 1965
In Philadelphia, we have had 13 separate calendar days in which
an inch or more of snow has fallen this season. We have a chance to
make it 15 calendar days which would give this season sole possession
of second place. 14 calendar days occurred in 1898-99 while the
record is 17 calendar days in the 1917-18 season.
Speaking of second place, an additional 2.7 inches would give
Philadelphia (62.9 inches currently) the second snowiest season on
record, surpassing the 65.5 inches during the 1995-6 season. The
all-time record is 78.7 inches in 2009-10. It appears safe through
this event. If 6.6 inches or more of snow were to fall early next
week, it would be the first time ever there have been four double
digit months of snowfall in one season in Philadelphia.
Atlantic City (33.7 inches currently) needs one tenth of an inch of
additional snow to crack the top 10 snowiest seasons on record and
8.7 additional inches to supplant 2002-3 as the 5th snowiest. The
most recent snowiest winter was 2010-11 (ranked 8th) at 38.0 inches.
Numero Uno is the winter of 2009-10 at 58.1 inches.
Wilmington (52.9 inches currently) needs 3.1 additional inches to
supplant 1995-6 as the second snowiest season on record. The record
is 72.8 inches during the 2009-10 season.
Allentown seasonal snowfall ranks:
75.4 inches in 1993-4
71.4 inches in 1995-6
67.2 inches in 1966-7
66.9 inches in 2013-4
Marine...Small Craft Advisory until 3 PM EDT Saturday for anz450>455.