Scientific Forecaster Discussion
fxus61 kphi 181316
Area forecast discussion
National Weather Service Mount Holly New Jersey
916 am EDT Wed Sep 18 2019
high pressure across eastern Canada will build southward into the
mid-Atlantic through Thursday and then shift south of the area on
Friday. The high will then push offshore this weekend as a cold
front approaches our region Monday.
Near term /until 6 PM this evening/...
930 update: no significant updates to previous forecast other
than adjusting hourly T/TD to current trends.
High pressure across New England this morning will continue to
move south today. This will result in another dry day across the
region. Much of the recent guidance is indicating that some
clouds will develop/move across ern PA and New Jersey this morning
before clearing out this afternoon. We'll keep the mention of
the clouds although the most recent satellite images do not show
any attm. After a chilly morning, with lows in the 40s across
the N/W and 50s elsewhere, highs will climb into the low/mid 70s
today. Winds will be mostly east or NE at 5 to 10 mph.
Short term /6 PM this evening through 6 am Thursday/...
high pressure settles across the area tonight. Mostly clear skies
and light winds are expected. Lows will drop into the mid/upper 40s
across the north/west and mostly low/mid 50s elsewhere. Readings right
along the shore will remain closer to 60 however.
Long term /Thursday through Tuesday/...
overview: with the exception of marine and surf zone hazards, a
mostly tranquil weather pattern will continue through this week.
Early next week, a cold front approaches bringing our next chance
for measurable precipitation over our region
Thursday through Saturday...through this period, the dominant
feature will be the large surface high which will continue to slowly
build southward. With the center of the high south of our region by
Friday, we will see low level flow shift to be off shore. The
combination of this, plus a building ridge in the mid and upper
levels will lead to a significant warming trend Friday into
Saturday. By Saturday, temperatures will be 5 to 15 degrees above
normal, with highs mostly in the 80s across the region.
Sunday...Sunday could be the warmest day of the next 7 days. In
addition to the building ridge mentioned above, low level flow will
be southwesterly, leading to temperatures 10 to 15 degrees above
normal with highs mostly in the mid to upper 80s (with the exception
of the shore and higher terrain in the southern poconos). I
currently have not included any 90s in the forecast, but the warmest
guidance is showing that potential, primarily for the I-95 corridor.
Monday...there is considerable uncertainty with the timing of the
next cold front. Some guidance shows this coming through early on
Monday, leading to the highest chance for precip Sunday night into
Monday morning with highs on Monday mostly in the 70s. However,
slower solutions (particularly in the ecmwf) show the front not
arriving until late on Monday. If this were to occur, then Monday
could beat out Sunday for the warmest day of the week. For now, have
stayed close to the previous forecast and a blend of all guidance.
Tuesday...in the wake of the cold front, temperatures should drop
back closer to normal, with highs mostly in the 70s to lower
Aviation /13z Wednesday through Sunday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.
Today...VFR expected. Sct-bkn clouds this morning across ern PA and
parts of New Jersey with some onshore flow adding some low level moisture.
After that, mostly sunny skies expected. Winds mostly east to NE around
10 knots. Winds may be a bit stronger near the shore areas.
Tonight...VFR continues with mostly clear skies. Light NE winds.
Thursday through Sunday...mostly VFR conditions are expected through
this time. Winds will still be easterly on Thursday, but by Friday
winds will be shifting to westerly and northwesterly.
strong high pressure builds down from Canada today and
extends across the region tonight. A decent NE flow ahead of the
high will keep Small Craft Advisory conditions for the ocean waters today and into
tonight. Winds and seas across Delaware Bay will probably remain sub-
Small Craft Advisory with some gusts to around 20 knots expected. Fair weather today
Thursday and Friday...Small Craft Advisory conditions are likely to continue with
elevated seas through this time. Wind gusts near 25 kt are also
possible Thursday morning, but should subside after that.
Saturday and Sunday...once seas subside below 5 feet, likely on
Saturday morning, winds and seas should stay below Small Craft Advisory criteria
through the remainder of the weekend.
A high risk for the development of dangerous rip currents is
expected today. Enhanced conditions (either moderate or high
risk) will likely remain around for several days with Hurricane
Humberto well offshore sending swells back across our waters.
New Jersey...high rip current risk through this evening for njz014-024>026.
Delaware...high rip current risk through this evening for dez004.
Marine...Small Craft Advisory until 6 am EDT Friday for anz450>455.