NWS Philadelphia/Mount Holly wrote its last area forecast discussion before the first event at Jun 19, 8:38 AM EST, 1 hour 52 minutes earlier.
Area forecast discussion, Jun 19, 8:38 AM EST, 1 hour 52 minutes before
Area Forecast Discussion
National Weather Service Mount Holly NJ
938 AM EDT Sun Jun 19 2022
.SYNOPSIS...
Steady northwest flow will continue into Monday as low pressure
will remain near the Canadian Maritimes and high pressure will
build across the Great Lakes and into the Ohio Valley. A trough
may bring precipitation to the region Tuesday into Wednesday.
Eventually, the low off the east coast will move away from the
region, allowing warmer air to build in to our region, though
when exactly this will occur remains uncertain.
&&
.NEAR TERM /THROUGH TONIGHT/...
Morning Update...
Little change to the going forecast, with a very nice day getting
underway. Winds are already gusting 25 to 30 mph, and these sort of
gusts will continue through the day. As expected, much more sunshine
today than yesterday with a dry column above us, and this should
continue as we warm into the 70s. Previous discussion follows...
Satellite imagery early this morning depicts upper level low
pressure swirling off the southern New England coast. Surface
low pressure is now up in the Canadian maritimes. Surface high
pressure is centered over the Great Lakes.
Dry air aloft and at the surface should predominate for Sunday.
A cool start will become a mild and breezy day, with plenty of
sunshine expected. The sunshine will allow temps to rise back
into the 70s for most, which is still a bit below normal, but
not as cool as yesterday when many areas spent most daylight
hours in the 60s. Humidity will be noticeably low, with readings
likely dropping to near 30 percent, with some areas possibly
slipping into the 20 percent range.
Low pressure will slide further northeast tonight and high
pressure will slide towards the central Appalachians. This will
allow for a weaker gradient, and a better chance of decoupling
tonight. Clouds will remain few and far between as well. This
may help make tonight cooler than Saturday night has been so
far, but warm advection will start getting underway aloft, and
this may reduce the risk of records. Nonetheless, still one more
unusually chilly night expected, with most locales deep into the
50s and some places touching the 40s.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
A warm front will start to develop to our west on Monday as warm
advection gets underway in earnest while high pressure slides to
our south. However, for Monday, that front will not result in
much more than some increasing mainly high clouds. Enough warm
air will have already moved in aloft such that, when combined
with the sun which should still be in greater supply than it was
Saturday, temps should return to near 80 degrees for many. Winds
will also be notably lighter.
The warm front will try to make progress into the region Monday
night into Tuesday, accompanied by a weak shortwave aloft. This
will result in thicker cloud development, along with a risk of
showers. Right now, best odds favor the north, but there is a
risk further south as well. Timing looks to favor the morning
for much of the area, though far northeastern areas will see the
best odds into the afternoon. This timing difference may make
the difference between thunderstorm chances, which look elevated
in the afternoon across our northeastern regions, and lower
elsewhere. Temps will probably actually be cooler overall than
on Monday thanks to the rain potential and clouds, with more
locales likely stuck in the 70s, though humidity will be
elevated. Lows Monday and Tuesday nights will be considerably
milder however, with readings near 60 common Monday night and
low-mid 60s for Tuesday night.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Overview: Chances for precipitation exist across the region on
Wednesday. After that, it is uncertain how the pattern will
evolve to end the week.
Details:
Wednesday...A trough and associated weak warm front, combined
with the fact that our region could be situated under the right
entrance region of an upper level jet developing on the backside
of the upper level low off the east coast will mean an chance
for rain across the region. However, depending on how far away
from our region the mid/upper level low off the coast develops,
could mean big changes in the temperatures and even if
precipitation on this day will be more stratiform (with a
persistent marine layer) or convective (more on this below).
Thursday through Saturday...We'll be watching model and
guidance trends very closely over the next several days to
determine exactly how this pattern will evolve. The mid upper
level trough currently over the Pacific NW should progress east
around mid week. This in turn should result in the high
amplitude ridge currently over much of the central U.S.
flattening out. That much has been pretty consistent run to run
and between models/ensemble members. Most model runs and
ensemble members also depict the evolution of the second trough
currently over the NE U.S./Canadian Maritimes deepening and
intensifying into a closed low through this period as well. What
is much less certain is where the closed low will develop
relative to our region. As compared to the 12Z Sat model runs,
there has been a flip in some of the deterministic models with
the GFS now depicting the low closest to our region (which would
mean persistent northeasterly flow, marine layer, and thus
temperatures remaining well below normal). The ECMWF and CMC
continue to show a closed low off the SE coast, though far
enough away from our region now, that what remains of the mid
level ridge would have the opportunity to build over our region
Wednesday into Thursday resulting in temperatures getting closer
to normal. The CMC even depicts the closed low being weaker,
with some of the original trough remaining progressive in the
northern stream as an open wave trough. All that being said,
there is too much uncertainty and inconsistency to go with any
single solution, so I've gone with a blend of guidance both for
PoPs and temperatures. However, there is the potential for
temperatures to be much lower than the current forecast, and
precipitation to be more stratiform and widespread through the
late week period.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Today...VFR. Northwest winds 10 to 15 kt with gusts to 25 kt.
High confidence.
Tonight...VFR with generally clear skies. Northwest wind 5 to
10 kts. Moderate confidence.
Outlook...
Monday...VFR with generally clear skies during the day.
Northwest wind 5 to 10 kts. Winds decreasing with increasing
cloud coverage Monday night. Moderate confidence.
Tuesday...Mainly VFR. Chance for showers, peaking in the
morning, may cause temporary local restrictions. Winds
southeasterly 5-10 kts becoming light and variable overnight at
night. Low confidence.
Wednesday and Thursday...Prevailing VFR, though periods of
lower conditions with showers, thunderstorms, and low clouds are
possible. SE Wind 5 to 10 kt. Low confidence on most aspects of
the forecast.
&&
.MARINE...
Today...The SCA continues through the day for both the local
Atlantic coastal waters and Delaware Bay. Northwest winds will
be a little weaker than on Saturday, but are still likely to be
around 15 to 20 kt with gusts to 25 kt. Seas 3 to 4 ft. Choppy,
short period sea conditions likely.
Tonight...Marine headlines possible. An extension of the
current SCA set to expire at 6 PM this evening may be needed
with current forecast wind gusts 20-25 kts through the early
overnight hours. Seas of 2 to 4 feet generally expected
overnight.
Outlook...
Monday-Tuesday...Marine headlines unlikely. Winds 10-15 kts
weakening through the day Monday and then remain generally weak
(less than 10 knots) through the remainder of the period. Wind
direction likely offshore Monday becoming onshore Tuesday. Seas
of 2 to 4 feet generally expected.
Wednesday and Thursday...winds and seas should stay below SCA
criteria.
Rip currents...
Northwest winds 15-20 mph with gusts up to 25 mph for today.
Breaking waves should be 2 to 3 feet with a medium period
northwest wind wave and a wave height of around 3 ft. There is a
LOW risk for rip currents along the coasts of Delaware and New
Jersey today.
Northwest winds will range from 10 to 15 mph on Monday with
breaking waves 2 to 3 feet and a wave height of around 3 ft.
There is a LOW risk for rip currents along the coasts of
Delaware and New Jersey on Monday.
&&
.CLIMATE...
We may approach record lows this morning and again Sunday
night/Monday morning. Here are the records (from north to
south).
Sunday AM Monday AM
MPO 36 in 1986 36 in 1940
ABE 46 in 1999 44 in 1926
RDG 48 in 1986 48 in 1926
TTN 48 in 1999 49 in 1926
PHL 53 in 1946 51 in 1956
ILG 50 in 1954 48 in 1956
ACY 42 in 1980 47 in 1956
55N 51 in 1909 51 in 1886
GED 41 in 1954 43 in 1956
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ430-
431-450>455.
&&
Synopsis...Johnson
Near Term...O'Brien/RCM
Short Term...RCM
Long Term...Johnson
Aviation...Johnson/RCM
Marine...Johnson/RCM
Climate...WFO PHI