Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Mount Holly New Jersey
357 am EST Friday Feb 12 2016
an area of low pressure will remain to our southeast today, while
another moves out of the Great Lakes and into New England tonight
into Saturday morning, pulling a cold front across our area.
Bitter cold air will move into the area over the weekend, before
high pressure builds across the area Sunday. This high will build
offshore Monday. An area of low pressure will move up the East
Coast and affect our area Monday night into Tuesday. High pressure
will return for Thursday into Friday.
Near term /until 6 PM this evening/...
middle and upper level low digs southeast from Canada, through the
day. In response, should see the surface low in the Great Lakes
region intensify as it lifts northeast. Though this would suggest
a middle level warm air advection pattern. However, with surface
winds still northwesterly, albeit considerably lighter than
yesterday, do not expect this to translate into higher maximum temperatures
as compared to yesterday. If anything, temperatures will likely be a
degree or two lower than yesterday.
Snow...lapse rates aren't quite as impressive as what we saw
yesterday when there were scattered snow showers. However, what
this pattern lacks in lapse rates, it looks to make up for in lift
associated with the approaching middle and upper level trough. Thus,
there should be a chance for snow showers across the region, with
higher chances towards the Poconos.
Short term /6 PM this evening through 6 am Saturday/...
could see snow showers linger through midnight as the surface
trough crosses the region. Continued cold air advection will mean
another very chilly night, with lows generally in the teens
(except in the Poconos and northwest NJ, where single digits are possible
especially over the higher terrain). However, winds should be
light, so at this point it doesn't look like anyone will reach
Wind Chill Advisory criteria.
The exception to this is in the Poconos, which could come close
to advisory criteria early Saturday morning. However, to keep
things simple, we will just mention the potential with the wind
chill warning which will be starting Saturday morning.
Long term /Saturday through Thursday/...
the main focus on the extended forecast is the bitter cold
affecting the area this weekend. Sub-zero temperatures and wind
chills will affect the area Saturday through Sunday. On Saturday,
an area of low pressure to the north will weaken as it moves into
northern New England, while the low off the coast strengthens. An
Arctic front will move across the area during the day Saturday,
which will usher in much colder air. In fact, temperatures will
likely fall through the day Saturday. There will also be a chance
for isolated snow showers across the area as there will be fairly
steep low-middle level lapse rates combined with enhance low-middle
level moisture within the northwest flow. Speaking the northwest
flow, winds Saturday will likely gust 35-40 mph, with some area
approaching advisory levels; we've held of on any Wind Advisory at
Any snow showers should end by the evening, but the wind will
remain strong through the night. Along with the winds, the bitter
air will continue to push into the area. The wind chill warning
across the Poconos will continue through the night. For the
remainder of the area, sub-zero wind chills will occur, with most
areas reaching into -5 to -15 range.
Sunday will remain cold, although winds will weaken some during
the day as high pressure begins to build across the area. Sunday
into Sunday night will remain precipitation free as the air mass
will be quite dry; although moisture begins to increase Sunday
night as high pressure builds offshore.
However, as we go into Monday, moisture continues to increase
across the area within the return flow with high pressure
offshore. A low pressure system will be strengthening along the
Gulf states Monday, while a warm front begins to lift northward
toward our area. Overrunning precipitation may begin affecting the
area starting Monday, and with temperatures being cold enough,
precipitation will likely start out as snow for much of the area.
The low will continue to strengthen Monday night, and make its
way into our area Tuesday. Warmer air will move into the area as
the low makes its way northward, so most areas are expected to
turn to rain during the day Tuesday. As the low lifts to our north
Tuesday night, we could have some wrap around precipitation on
the backside, which could turn back to snow.
Northwest flow will be in place Wednesday and Wednesday night as
the low lifts well to our north, and high pressure builds to our
west.Some showers are possible across the area within the
northwest flow.The precipitation could change to rain for many
areas during the day as temperatures will remain warm.
High pressure will build across the area Thursday into
Thursday night which will allow for dry conditions to return the
Aviation /09z Friday through Tuesday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.
Predominantly VFR conditions are expected through late this
afternoon. By 21z, chances for snow showers increase across the
region lasting through the evening hours. With the snow showers,
expect MVFR, and possibly brief IFR conditions. At this point,
expect the highest risk of snow showers to include kabe, krdg, kttn,
kpne, and kphl, although there is a small chance at the other taf
sites as well.
Snow chances should decrease considerably after 06z. However, MVFR
ceilings may persist beyond that.
Saturday...generally VFR ceilings. Isolated snow showers possible,
which could reduce ceilings/visibilities temporarily. Northwest winds
increasing Saturday to 15-25 knots with gusts up to 40 knots.
Saturday night and Sunday...VFR conditions expected. Northwest winds
10 to 25 knots with gusts 30-35 knots early, diminishing some overnight
into Sunday. Gusts still 20-25 knots overnight into early Sunday.
Monday-Monday night...degrading conditions with MVFR/IFR likely
through the day Monday into Monday night. Snow possibly
beginning Monday for many areas, possibly mixing with rain at
times for some areas.
Tuesday...MVFR/IFR conditions continuing into Tuesday.
Precipitation may change over to rain for many areas during the
should see a lull in the winds and seas today and through the
first half of the night but expect winds to increase considerably
after midnight, reaching gale force on all the waters before dawn.
With the increasing winds, also expect freezing spray rates to
increase, so have issued a freezing spray advisory for the same
period as well.
Saturday-Saturday night...Gale Warning continues with strong
northwest flow across the area. Freezing spray advisory remains in
effect as very cold air and strong winds will lead to at least
moderate freezing spray.
Sunday-Sunday night...Gale Warning and freezing spray advisory
continue into Sunday morning. However, winds will diminish through
the day and Sunday night as high pressure builds into the area.
Monday-Tuesday...at least Small Craft Advisory conditions will
likely return to the area as strong low pressure moves up the East
Coast Monday into Tuesday.
near record cold is expected for portions of our area Sunday
morning and by far the coldest air of the season so far.
Anticipating temperatures throughout our forecast area within several degrees
of zero (wind is the equalizer) anytime from midnight through 8 am
Sunday except colder kmpo (near -12f). This has been advertised by
the GFS/European model (ecmwf) 2m temperatures cyclically since at least the 00z/7
operational cycles. Therefore, best chance for record equaling or
exceeding for Valentines day the 14th would be kabe, kttn, kphl
Snow cover may help a bit I-95 northwestward...and we'll see
where we are with snow cover by Thursday evening. New dustings
appear on the way through Friday night.
Please note... guidance in part is being climatology biased higher than
what the oncoming GFS/European model (ecmwf) literal airmass and 2m temperatures are indicating
for Sunday morning. Temperatures Sunday morning in the urban areas should
be about 25 colder than normal. That means guidance temperatures for phl
of 5 and 6 degrees appear too warm...especially with a normal
Philadelphia low on Sunday of 28.
Have seen the 12z/11 2m temperatures for phl...1 above ranging down to
-11 at kmpo and am liking those values as within 2f of the
Record low Max's can only occur for this event on Sunday the
14th, if then. Those have been added recently below.
Site 2015-16 coldest so far record low Feb. 14th ----rer low maximum
Abe 8 -1 in 1979 14-1979
Acy 10 -6 in 1979 13-1979
Phl 12 +2 in 1979 14-1979
Ilg 12 -4 in 1979 13-1979
Ridge 10 -4 in 1983
Ttn 9 0 in 1916
Ged 13 -7 in 1979
Mpo -1 -12 in 1970
So, this will be wind driven cold with many areas experiencing
wind chill values of 15 to 25 below zero...possibly 30 below in
the hills and mountains of northwest New Jersey and northeast
PA...wind chill warning from 6 am Saturday to 1 PM EST Sunday for
New Jersey...wind chill warning from 6 am Saturday to 1 PM EST Sunday for
Marine...freezing spray advisory from 4 am Saturday to 10 am EST Sunday
Gale Warning from 4 am Saturday to 10 am EST Sunday for anz430-