Tonight:
Partly cloudy, with a low around 65. North northwest wind around 3 mph.
Friday:
Sunny, with a high near 84. North northwest wind 3 to 9 mph.
Friday Night:
Mostly clear, with a low around 59. North northwest wind 3 to 7 mph.
Saturday:
Sunny, with a high near 84. North northwest wind 3 to 7 mph.
Saturday Night:
Mostly clear, with a low around 62. North northwest wind 1 to 5 mph.
Sunday:
Sunny, with a high near 87.
Sunday Night:
Mostly clear, with a low around 64.
Monday:
Mostly sunny, with a high near 87.
AREA FORECAST DISCUSSION
National Weather Service Mount Holly NJ
758 PM EDT Thu Sep 21 2017
Weather Synopsis:
Tropical storm Jose is expected to weaken as it meanders off the New
England coast through this weekend. Meanwhile, high pressure over
southeastern Canada will expand southward into the mid Atlantic
states. During the early to middle part of next week, Hurricane
Maria is forecast to move northward over the offshore Atlantic
Ocean waters between Bermuda and the Middle Atlantic states. A
cold front is expected to move through our area in the Wednesday
and Thursday time frame as Maria probably passes by, well to
our east.
Near Term:
UNTIL 6 AM FRIDAY MORNING -
630 PM ESTF: minor adjustments to a few temps tonight, especially
warmer by a couple of degrees early this evening...but
effectively no change to your forecast.
Tropical Storm Jose is expected to continue its gradual weakening
through tonight while still remaining nearly stationary about
150 miles southeast of Nantucket, MA or about 330 miles due east
of LBI, NJ.
It still has impressive winds in the observed data from southern
New England to our Texas Tower buoy 70 mi e of NJ.
Drier air over the west portion of southern new England and the
Hudson Valley may not arrive in our area until sometime tomorrow
or tomorrow (Friday) evening.
In the meantime...high clouds will prevail tonight with some
spotty sc at 6000 ft here and there.
The setup for radiational fog in the river valleys of NE PA and
NW NJ may not be nearly as favorable as in recent days (and as
climo) because of variably thick high cloud cover from Jose.
Low temperatures should range from the mid 50s along the I-80
corridor to the mid 60s along the I-95 urban corridor and near
the coast.
Short Term:
6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY -
The NHC forecasts Tropical Storm Jose to undergo post-tropical
transition Friday. The center of Jose will either continue to
stall near its current position or start to drift ever so slowly
westward but still remain comfortably offshore by several
hundred miles.
Winds gusts to 20-25 MPH are possible in NJ on Friday as the
western fringe of Jose`s wind field edges westward slightly.
Also, there is multimodel guidance indicating not only some
denser cirrus cloudiness from Jose but also a deck of 6000
broken is likely to develop in NJ.
A westward drift would allow for denser cloud cover from Jose to
spread back toward the northern mid-Atlantic coast on Friday and
perhaps as far inland as the Delaware Valley late in the day.
Temperatures will have a dependency on how far west the cloud cover
progresses. For now, clouds shouldn`t have a huge impact on
temperatures across inland locations from I-95 west. Forecast
highs range from the upper 70s in the higher elevations of NE
PA/NW NJ and near the coast to mid 80s near Phila and points
S/W.
Friday is still expected to remain dry with outer rain bands from
Jose staying offshore. However, could see scenario, albeit an
unlikely one, where one of these bands reaches the coast during the
morning.
Long Term:
FRIDAY NIGHT THROUGH THURSDAY -
The forecast challenges during this time frame will be high temps
Saturday through Monday and the eventual track of Hurricane Maria.
A complex mid-level pattern will evolve over the eastern US and
southwest Atlantic, with a southern stream rex block, eventually
breaking down with the approach of height falls associated with a
northern stream trough late in the period. Meanwhile, Hurricane
Maria is forecast to move northward through a weakness in the
subtropical ridge, under the increasing influence of a mid-level
trough along the eastern fringe of the rex block, e.g., remnants
of Jose, by the middle of next week.
In terms of high temperatures, the first full week of fall will
average above normal across our area. In fact, high temps in the
Saturday through Monday period will be around 10 degrees above
normal! The airmass will be generally dry with a light surface flow
in place. It will be cooler near the coast with a sea-breeze on
Saturday, and a more pronounced synoptic onshore flow Sunday into
Monday. There is some uncertainty in high temps, given the spread
exhibited in the ensembles, although a similar air mass lends to
more of a persistence forecast.
With the synoptic flow becoming onshore during the second half of
the weekend and persisting into the midweek, low-level moisture will
gradually increase, with perhaps some contribution from the remnants
of Jose as well. We are noting some of the GEFS ensemble members
bringing measurable precipitation into the coastal plain on Tuesday,
well in advance of the anticipated cold frontal passage Wednesday
into Thursday. Therefore, we have maintained slight chance PoPs in
the coastal plain beginning Monday night, expanding to chance PoPs
over the entire region on Wednesday.
The forecast also becomes uncertain in the Tuesday through Thursday
period and will be highly dependent on the eventual track of Maria,
including the extent of its interaction with the approaching cold
front. We continue to stay closer to a consensus of the guidance,
which takes the cold front offshore Wednesday night, thereby
introducing a drying trend by Thursday.
Stay tuned to the latest advisories and forecasts from the
National Hurricane for more information on Jose and Maria.
Climate:
Records may post here in a day or two for either Sunday or
Monday as its possible max temps may exceed 90 degrees.
Example: Allentown`s record for both Sunday and Monday is 90 -
set in 1970 on both days.
Click for full NWS PHI Office Area Forecast Discussion
