Scientific Forecaster Discussion
fxus61 kphi 231934
Area forecast discussion
National Weather Service Mount Holly New Jersey
334 PM EDT Wed Oct 23 2019
high pressure will continue to build into the mid-Atlantic then
weaken and move offshore throughout the day Thursday. Low pressure
will pass from the Ohio Valley and cross the eastern Great Lakes
through the weekend. An associated front will stall out across the
region by Monday then a much stronger cold front will arrive
Near term /until 6 am Thursday morning/...
high pressure located in the southern Appalachians this afternoon
will continue to build slowly northeastward. We are anticipating a
clear sky for tonight.
The gusty west northwest wind this afternoon should diminish quickly
during the hours around sunset. The wind is forecast to become light
and variable for the overnight.
Low temperatures are expected to favor the upper 30s and lower 40s,
with readings not getting below the middle 40s in urban areas and
along the immediate coast.
Patchy frost is possible in the Poconos and in northwestern New
Jersey where the growing season has already come to an end. While
there may be some isolated frost along and to the north of the
Interstate 78 corridor, it does not appear as though it will be
widespread enough to warrant an advisory.
Short term /6 am Thursday morning through 6 PM Thursday/...
high pressure is forecast to become located in our region on
Thursday morning before drifting off the coast in the afternoon. We
are expecting another sunny day with seasonable temperatures. Highs
should favor the 60s with a light southwest wind.
Long term /Thursday night through Wednesday/...
by and large, a very seasonable weather pattern is in store for the
long term period with near normal temperatures expected through
early next week along with a few rounds of dry weather and rain
Low pressure is forecast to pass quickly from the Mississippi River
valley across the southern Great Lakes by early Thursday morning.
Meanwhile, high pressure across the mid-Atlantic will be pushing
east toward the coastal plain before weakening and moving offshore
throughout the day Thursday. Weak synoptic forcing and weak surface
flow will allow the cold front associated with the aforementioned
low pressure to drift into the forecast area on Friday. Dry and
tranquil weather will prevail in the mean time with seasonable
temperatures on Friday.
The front will stall out briefly then return northward as a warm
front by late Saturday into early Sunday as low pressure passes from
the Ohio Valley and across the eastern Great Lakes through the
weekend. Onshore flow Saturday will likely result in mostly cloudy
skies and cooler temperatures with perhaps some patch drizzle or
isolated light rain showers, especially later in the day. The best
forcing for ascent will arrive from the approaching system by late
Saturday into the overnight hours and especially by early Sunday.
Medium range guidance still differs on the timing this system,
nevertheless a few rounds of rain showers can be expected during the
late Saturday to Sunday time frame, with the most widespread and
heaviest activity appearing most likely to occur early to mid-day
An associated cold front will then pass through the forecast area an
stall out across the region late Sunday into early Monday. On
Tuesday, a much stronger, pattern-changing synoptic system appears
to be shaping up for much of the eastern US. Again, medium range
guidance still differs on the timing and strength of this system,
but there does appear to be consistency in at least the system's
development by around the Tuesday-Wednesday time frame of next week.
Ahead of the front, at least a brief surge of higher dewpoints and
warmer air is probable. The system's cold front could bring rain
showers by as early as Monday or Tuesday or as late as Thursday. It
also appears probable to bring colder and drier air in its wake by
the middle to end of next week. The European model (ecmwf) and Canadian are notably
slower (by a couple of days) than the GFS with this potential
system, so will have to continue to monitor this period in the long
Aviation /20z Wednesday through Monday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.
Tonight...VFR. Mostly clear. West northwest wind 10 to 15 knots into
early evening, becoming variable 6 knots or less for tonight.
Thursday...VFR. Mostly clear. Variable wind 6 knots or less,
becoming southwest 4 to 8 knots.
Thursday night through Friday...VFR expected with southwest winds
5 kts or less.
Friday night...mainly VFR expected, but some MVFR possible in -shra
at rdg/Abe. Winds northwest around 5-10 kts.
Saturday...VFR initially, then low stratus and MVFR developing by
mid to late afternoon. Easterly winds 5-10 kts.
Saturday night through Sunday...sub-VFR expected with rain showers through
the period. Southeast winds shifting south around 10 kts.
Sunday night...lingering sub-VFR possible into the evening with
showers ending. Winds west to northwest less than 5 kts.
the Small Craft Advisory for the coastal waters of New Jersey will
be discontinued as wind speeds and wave heights subside.
A west northwest wind 10 to 15 knots this evening should decrease to
5 to 10 knots overnight. The wind is forecast to become southwest to
south on Thursday. Wave heights on our ocean waters should favor the
2 to 3 foot range. Waves on Delaware Bay will likely be 2 feet or
Thursday night through Saturday...conditions are expected to remain
below Small Craft Advisory criteria.
Saturday night through Sunday night...Small Craft Advisory possibly developing late
Saturday into early Sunday with southerly winds gusting up to around
25 kts and waves nearing 5 feet.