Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Mount Holly New Jersey
955 PM EDT Sat Oct 3 2015
high pressure will gradually build south through the early part of
the week. Meanwhile, the forecast track of Hurricane Joaquin takes
it to the east, and well away from our area. A pair of high pressure
systems will move into the area during the middle of next week. A
cold front will approach the northeast on Friday.
Near term /until 6 am Sunday morning/...
no further changes with the latest forecast update. Gusty and cool
conditions will continue across the area as stong northeasterly
winds remain due to tight pressure gradient between the high
across eastern Canada and the low/front to our south.
Scattered showers and areas of drizzle will continue to move in
off of the ocean during the overnight hours, although chances
will decrease from north to south through the night. Regardless of
whether or not we see any showers/drizzle, it will be overcast
across the region.
It will be a raw night out there and temperatures, although not
that far off of normal, will certainly feel cold. Temperatures to
the north and west will be in the 40s with low to middle 50s through
the I- 95 corridor. Areas to the south and east of there will be
more mild and remain in the upper 50s to lower 60s overnight.
Short term /6 am Sunday morning through 6 PM Sunday/...
gusty northeast winds will continue across the region with the
windiest places remaining towards the coast and especially toward
our southern areas. While it will remain fairly windy at the coast,
it looks like we should remain below Wind Advisory criteria.
With the continued easterly flow, some light showers can't be ruled
out so we continue to mention a chance closer to the coast and then
only a slight chance inland. Most areas look like they will remain
dry as the high starts to push south towards our area, bringing in
some drier air.
Temperatures don't appear to be quite as cold as they were today and
we should see highs rise into the upper 50s to middle 60s through much
of our area.
Long term /Sunday night through Saturday/...
for the most part, the long term will be dominated by a pair of
high pressure systems.
Sunday night and Monday...should see a drastic decrease in the
pressure gradient through this period, and as a result, should see
a drastic decrease in the winds as well. A few light showers may
linger near the coast Sunday night, but for the most part we're
expecting the region to be dry. With continued northerly flow and
lingering cloudiness, expect Monday, although warmer than today,
to be around 5 degrees below normal.
Tuesday through Thursday...high builds in over the region leading
to tranquil weather through out this period (with the exception
of some continued rough seas - see the marine section below). As
the upper level trough moves further away from the region 1000 to
500 mb thickness increases, leading to a modest warming trend
through at least Wednesday. Thus expect mostly near normal
temperatures through this time.
Friday through Saturday... in the upper levels, a short wave
trough will cross east out of the Great Lakes region, at the
surface, the low and its associated cold front will sweep through
the northeast U.S.. expect the cold front to push through our
region either late Friday or early Saturday. There remains some
chance for rain with this front, though this will depend on how
far south the upper level trough ends up tracking.
Aviation /02z Sunday through Thursday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy, and surrounding areas.
MVFR conditions, with brief IFR conditions early, will continue
across the terminals tonight as there will not be much change to
the current flow regime. Ceilings may lift a bit, but predominantly
MVFR conditions are expected through Sunday morning.
Winds remain gusty out of the northeast, especially toward the
coast where gusts up to 35 knots are occurring. Elsewhere, gust to
25 to 30 knots can be expected through the rest of the overnight
hours. Gusts should drop down a bit, possibly losing the gust
completely toward kabe/krdg overnight, but it will remain windy
through the taf period.
Some showers/drizzle may periodically continue to occur,
especially toward the coast.
Improving conditions should occur during the day Sunday with ceilings
lifing from lower end MVFR to upper end MVFR, possibly to VFR by
the end of the day. Winds will remain gusty through the day, with
the potential for gusts to diminish toward sunset Sunday.
Outlook... Sunday night and Monday...any remaining MVFR ceilings
gradually improving to VFR through this period. Northeast winds
continue with the highest gusts (around 25 kt) possible at kacy
Monday night through Thursday...mostly VFR conditions expected.
gale warnings continue for the area waters through Sunday night.
Gale conditions will continue on all of our coastal waters with
frequent gusts up to 45 knots. Winds should subside a bit
overnight but will remain pretty gusty. Wind gusts should drop down
closer to 40 knots later tonight and for Sunday.
Seas on the ocean have dropped several feet since earlier today and
will gradually drop through tonight and tomorrow.
Sunday night through Monday...winds should drop from gales to Small
Craft Advisory conditions through this time. Seas however should
remain near or above 10 feet through this period.
Tuesday through Thursday...though winds should remain below Small
Craft Advisory conditions, seas could stay elevated through middle
week, both as a result of lingering effects of this weekends system
and as wave groups from Joaquin reach our shore. Exact timing of
seas dropping to 5 feet or less is uncertain at this time.
820 PM update to cancel the coastal Flood Warning for the Delaware
River and the upper Delaware Bay (new Castle County, Delaware and Salem
County, nj) and replace it with a coastal Flood Advisory through
Sunday evening. Both the etss and dbofs tidal prediction came in
between one-half and one foot too high with this past high tide
cycle this afternoon/ evening. This guidance has also verified too
high with previous high tide cycles over the past couple of days.
The etss and ofs guidance may have partially taken into account
the bias and have trended lower for the early morning and late
afternoon/evening high tide on Sunday but likely are still too
high. The ofs prediction keeps Reedy Point and Philadelphia below
moderate stage for both high tides tomorrow while the etss
prediction is right at moderate. The in-house regression guidance,
which has verified the best thus far, barely gets Reedy Point to
minor tidal flood stage on Sunday.
The coastal flooding issues will continue across the region through
the remainder of the weekend as the deep northeasterly winds
The worst of the flooding (widespread moderate) will continue over
Cape May County New Jersey and eastern de, particularly in the back bays as
the onshore flow has not allowed the water that made it in there
during previous high tide cycles to drain. We'll continue to
highlight the threat of locally major tidal flooding in some of
these vulnerable back bays.
Along the Jersey Shore from Atlantic County northward, coastal
flooding are forecast to be near the upper end of minor. However,
will keep the coastal Flood Warning up as once again the back bays
will be at risk to moderate coastal flooding.
The coastal Flood Advisory was cancelled for the Eastern Shore of
the Maryland Chesapeake Bay. Water levels did not increase as previously
forecast. The newest tidal guidance, which took into account the
previous bias, no longer forecast advisory level flooding through the
The threat for moderate coastal flooding looks to end by Monday,
though minor flooding may occur.
PA...coastal Flood Advisory until midnight EDT Sunday night for
New Jersey...coastal Flood Warning until 6 PM EDT Sunday for njz012>014-
Wind Advisory until 6 am EDT Sunday for njz024>026.
Coastal Flood Advisory until midnight EDT Sunday night for
Delaware...coastal Flood Warning until 6 PM EDT Sunday for dez002>004.
Wind Advisory until 6 am EDT Sunday for dez004.
Coastal Flood Advisory until midnight EDT Sunday night for
Marine...Gale Warning until 2 am EDT Monday for anz430-431-450>455.