Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Mount Holly New Jersey
1250 PM 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 in during the weekend, before high pressure
builds across our 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 /through tonight/...
930 am estf: few changes. A nice day. Increasing then lowering
cirrus to a deck of clouds near 5000 feet late in the day. Wind
turning southwest with a few late day gusts of 15-20 miles per hour.
Flurries possible Poconos and extreme south edge of our area late
in the day.
Tonight...shallow moist advection on S-SW flow prior to the cold front passage.
Snow showers or flurries appear probable for a few hours near
midnight. SW wind may gust 15 miles per hour early tonight. Then a wind shift
to northwest and gusty 20-30 miles per hour by dawn Saturday.
Short term /Saturday/...
Wind Chill Advisory will Post this aftn, to connect to the already posted
wind chill warning for extreme northwest New Jersey and the Poconos. Still want
to review the updated details.
Deepening boundary layer momentum Transfer is featured associated
with the oncoming Arctic airmass invasion. Large low level lapse
rates and btv snow squall parameter indicating a possibility of
flurries or squalls but will the surface tt/dew point spread exceed 25f and
make those squalls just virga? Seems like best chance for a squall
would be the morning.
Am thinking of gusts 50 miles per hour in the Poconos and also scattered 50
miles per hour gusts developing in the krdg-kphl-kilg kacy and north side of
Delaware Bay slot for the afternoon. May issue a Wind Advisory for this at 330 PM
(potential Wind Advisory noon - 6p).
Otherwise widespread gusts 40 miles per hour Saturday with partly o mostly
sunny skies .. tending to clear late day.
Long term /Saturday night 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.
Any Saturday 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 /18z Friday through Wednesday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.
This evening...VFR conditions will continue with light south to
southwest winds across the terminals.
Tonight through early Saturday morning...a cold front will approach
the region from the west. An area of snow showers looks to develop
in advance of the frontal passage and snow showers are expected to
reach all terminals. Visibilities and ceilings are expected to drop
to MVFR conditions as the snow showers move through. Once the
showers clear the region, between 05-09z from west to east, a return
to VFR conditions is anticipated. Snow showers may dissipate before
fully reaching kacy and kmiv but latest guidance leads US to include
the snow showers for late tonight/early Saturday.
Saturday...the biggest issue affecting aviation travel on Saturday
will be the winds. Behind the aforementioned cold front, the winds
will quickly turn to the west then northwest and become very gusty.
Sustained winds will be around 15-20 knots by 12-15z and increase
into the afternoon. Wind gusts from 25 knots early will increase to
near 40 knots by the afternoon.
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
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 still expected for portions of our area Sunday
morning, despite the MOS guidance...and by far the coldest air of
the season so far.
Anticipating temperatures throughout our forecast area within several degrees
of 2 above (wind is the equalizer) anytime from midnight through 8
am Sunday except colder kmpo (near -10f). This is 2f warmer than
expected the past few days.
Tracking NAM 3hrly 2m, bl and 1000mb temperatures and it is much colder
than the global models MOS. NAM has been steady the past 4 cycles.
Phl+2 (-19c 1000mb), mpo -11 (-23c). Using the NAM guidance and
possible blend with 2m NAM/GFS temperatures Sat afternoon.
Best chance for record equaling or exceeding for Valentines day:
kabe, kttn, kphl and kmpo.
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
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-