Area Forecast Discussion
Issued by NWS Mt. Holly, NJ-- Remove Highlighting --
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FXUS61 KPHI 301951
Area Forecast Discussion
National Weather Service Mount Holly NJ
351 PM EDT SAT JUL 30 2016
A weak frontal boundary remains near our area into early next
week. A few weak low pressure systems will track along the
boundary, bringing periods of showers and thunderstorms. High
pressure will build across our area Tuesday into at least early
Thursday before moving off shore as a cold front approaches the
region the end of the week.
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A warm frontal boundary and a mid-level shortwave have led to the
development of showers and thunderstorms across most of Eastern PA
and northern NJ. These features will be slow to move tonight. This
means that the focus of the highest rain chances tonight are
across the same regions. Later tonight, showers and thunderstorms
over Eastern PA and MD will likely move east. However, potential
exists for convection to decrease in coverage overall as shown the
last few HRRR runs. PW values are rather high, near 2 inches
currently with a lot of moisture streaming northward into the
region. This will promote a heavy rain and localized flooding
threat with some of the showers and thunderstorms. Currently, the
threat looks too localized for the issuance of a flash flood
watch. With plenty of clouds around and a southerly flow,
temperatures will stay warm overnight with lows in the 70s for
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
The frontal system will still be over the region through Sunday with
the main cold front moving southeast toward the region late in the
day. This will result in another round or two of scattered showers
and storms. The highest chances of showers and storms will be across
the northern portions of area, closer to the warm front. The initial
shortwave will be east of the area on Sunday, pulling in some
slightly drier air to the region. However, a lot of moisture will
remain in place leading to a threat of heavy rain with any
thunderstorms. Where more sun comes out across the southern half of
the region, highs have a good shot of reaching 90. Further north
with more clouds and thunderstorms, highs will be closer to 80.
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
Medium range models are fairly consistent bringing the mid level
trough across the region Sunday night through Monday night. Expect
enough instability, moisture, and lift associated with the broad
trough and embedded shortwaves for a continuation of the unsettled
weather. Pwats should still be in the 1.5-2 inch range at this
point so any storms could contain heavy rainfall. Expect residual
lingering boundaries to be the primary focus for any thunderstorm
As the trough moves east Tuesday, northwest flow overspreads the
region. A surface cold front will bring cooler temps, mainly in
the 80s, as well as drier air which will linger into at least
Model solutions begin to diverge at the end of the work week,
with the gfs showing a small but potent shortwave moving across
the forecast area. Despite the differences, multiple models show a
cold front moving across the region Friday night into Saturday.
Due to uncertainty in timing will include only low chance pops
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Showers and thunderstorms will occasionally impact KRDG, KABE and
KTTN through the remainder of the afternoon. These storms will
likely create MVFR or IFR ceiling and visibility restrictions for
short intervals. Thunderstorms may form at TAF sites further
southeast including KPHL, KPNE, KACY, KILG and KMIV late this
afternoon and early evening. The loss of daytime heating will
reduce the thunder threat during the evening.
A few more rounds of showers will likely occur throughout the night.
Ceilings will likely lower throughout the night as well with MVFR
ceilings and visibilities currently expected toward or just after
midnight. Outside of thunderstorms, winds will generally be 10 knots
On Sunday, Additional scattered showers and thunderstorms are
possibile. However, a break or a period of lesser coverage is
possible in the late morning hours. Have kept the TAFS dry beyond 15z
Sunday given the uncertainty. Lower ceilings should lift by late
morning to VFR.
Sunday night through Monday night...Potential for MVFR ceilings
Monday morning, otherwise VFR with scattered to broken cloud
cover. Some showers and thunderstorms will be around especially
Sunday and this will lead to mainly local and brief restrictions.
Tuesday and Thursday...VFR overall as high pressure builds in.
Waveheights tonight will be around two feet with southeast winds
from 10-15 knots. Waveheights will increase some tomorrow pushing
four feet on the New Jersey coastal waters and around three feet
Sunday night through Thursday...An onshore flow Sunday should
increase some especially across the northern coastal waters, with
gusts to about 20 knots. It appears at this point that conditions
remain below advisory criteria. Otherwise, a weak pressure
gradient should keep winds and seas mainly below Small Craft
Advisory criteria through Thursday. Main concern will be the
threat of some thunderstorms Sunday and Monday, however the
greatest concentration of storms may be inland.
The rip current risk for the remainder of the day is low.
However, with an increase in seas and winds on Sunday, a moderate
risk is currently possibile on the New Jersey coastline with a low
risk remaining in place further south where the increase will be
less with the seas.