Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Mount Holly New Jersey
1248 am EDT sun Oct 4 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 this morning/...
no further changes with the latest forecast update. Gusty and cool
conditions will continue across the area as strong northeasterly
winds remain due to tight pressure gradient between the high
across eastern Canada and the low/front to our south.
Spotty 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
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 this morning through 6 am Monday/...
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 /Monday 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 /06z Sunday through Thursday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy, and surrounding areas.
06z tafs continue windy MVFR conditions through most of the
Rest of overnight...ceilings mainly between 1000-2000ft, some IFR ceilings
possible closer to the coast. While some non visibility restricting
drizzle is possible at all terminals, we just carried it at kacy
and kmiv withe some up to MVFR restrictions. Northeast winds will
average 12 to 18 knots with higher gusts except for far northwest
airports and terminals.
This morning...a higher MVFR ceiling is predicted with no visibility
restrictions. Northeast winds should mix a bit more and will
average 15 to 20 knots with gusts 30 to 35 knots closer to the
coast and between 20 and 30 knots inland airports/terminals.
This afternoon...far northwest terminals ceilings becoming VFR.
Elsewhere we are maintaining a higher MVFR ceiling. Wind direction and
speed similar to the morning.
Sunday evening...ceilings remaining MVFR at kmiv and kacy with some
gusty northeast winds continuing as high as 20 to 30 kts.
Elsewhere we will forecast a VFR cig, but highest confidence far
northwest. We keep northeast winds at about 10 to 15 knots, but
drop the gusts. Highest confidence of this forecast occurring is
for northern airports.
later 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 and kmiv.
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 tonight for paz070-
New Jersey...coastal Flood Warning until 6 PM EDT this evening for
Wind Advisory until 6 am EDT early this morning for njz024>026.
Coastal Flood Advisory until midnight EDT tonight for
Delaware...coastal Flood Warning until 6 PM EDT this evening for
Wind Advisory until 6 am EDT early this morning for dez004.
Coastal Flood Advisory until midnight EDT tonight for dez001.
Marine...Gale Warning until 2 am EDT Monday for anz430-431-450>455.