Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 230951

Area Forecast Discussion
National Weather Service Mount Holly NJ
551 AM EDT Fri Jun 23 2017

Low pressure will track well north of our area Friday and Saturday.
An associated cold front will cross our region during Saturday as
some tropical moisture moves ahead of and along it. High pressure
will then build well to our southwest Sunday into Monday. A weak
cold front will move through our area later Monday. High pressure
will then build across the Mid Atlantic Tuesday and Wednesday,
before shifting offshore Thursday.


Showers with heavy rain developing from a spoke of mid-level
shortwave energy associated with the remnant low of Cindy are
moving through the Appalachians and into the Mid-Atlantic and
Delmarva. These showers should enter northeast Maryland,
southeast PA by the start of the morning commute, and then these
showers will spread north and east as the morning progresses.

These showers are moving into a humid and unstable airmass with
surface dewpoints in the upper 60s to low 70s and ML MUCAPE
values around 1000 J/kg. Although there is no lightning
currently with these showers, going through this morning, there
should be enough instability for at least scattered
thunderstorms to develop. Given the abundant low level moisture
across the region with PWATs between 1.7-2", rain may be heavy
at times.

Wave passes through by midday, and any showers and thunderstorms
will taper off. With the approach of another shortwave this
afternoon and early evening, conditions will become unstable enough
to potentially support strong to severe thunderstorms. Will have
PoPs capped at chance for now.

With SW flow tapping into a subtropical airmass, highs today should
top off in the upper 70s to low 80s north and west of I-76, and in
the mid to upper 80s across most of southern and eastern NJ,
southeast PA, and the Delmarva. With dewpoints in the low 70s, the
heat index will be in the low to mid 90s.


Any showers and thunderstorms early will taper off in the evening.
Warm and humid conditions remain in place as the subtropical airmass
remains over the region. Overnight lows will be in the low to mid
70s, and dewpoints will be in the upper 60s to low 70s.

The remnant low of Cindy moves towards the Appalachians this
evening, and then towards the Delmarva prior to daybreak Saturday.
Showers and scattered thunderstorms will move into far western zones
after midnight, and then the heaviest precip will hold off until the
pre-dawn hours. Given the abundant moisture across the region, rain
may be heavy at times, and cannot rule out localized flooding.


A ridge of high pressure will be across the Middle Atlantic region
Sunday. A fair weather day is expected with temperatures right
around seasonal norms. The airmass will be much drier than both
Friday and Saturday, so it will be a good day for outdoor

A surface cold front and a slow moving upper trough will affect the
weather from Monday afternoon into Tuesday. The system will not have
a great deal of moisture to work with, but the colder temperatures
aloft will help develop showers and a few tstms during the period.
Pops are only in the slight chc or low chc range attm. Temperatures
thru the period will mostly be around 5 degrees below normal for
late June. Highs will be in the mid/upper 70s across the north and
close to 80 near metro Philadelphia and over Delmarva.

The rest of the long term looks dry with slowly moderating
temperatures and rising humidity levels. Highs will remain below
normal Wednesday and then rise to near normal for Thu/Fri. Most of
the models are showing high pressure across the area, slowly moving
offshore by Friday. A few showers Fri afternoon far N/W are
possible according to the 00Z EC.


The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

MVFR/IFR conditions will develop in SHRA and scattered TSRA this
morning, and then VFR conditions once those showers move north and
east of the local terminals. Another round of SHRA/TSRA possible in
the afternoon and early evening, and some storms could be strong to
possibly severe. Heavy rain is possible, and MVFR/IFR conditions

Conditions dry out in the evening, and then heavy rain, scattered
thunderstorms, and IFR and lower conditions possible in the pre-dawn
hours Saturday morning.

SW flow 5-10 KT today through tonight. Gusts to 20 KT possible this

Saturday/Saturday night...Lower CIGS/VSBYS with showers and
tstms mostly in the morning. Conditions improving late.
Sunday/Monday morning...VFR expected.
Monday afternoon thru Tue...Mostly VFR. Sct showers/tstms.


Sub-SCA conditions through this morning. SCA conditions develop this
afternoon on the ocean with 25-30 KT gusts and 4-6 ft seas. Will
also hoist a SCA for DE Bay, as 25 KT gusts likely, but that would
be for this afternoon and early evening.

SCA conditions on the ocean through tonight.

One round of showers and scattered thunderstorms will impact the
waters this morning through midday, and then another round of
showers and potentially strong thunderstorms possible late this
afternoon and early this evening.

The remnant low of Cindy will approach late tonight, and showers and
scattered thunderstorms with heavy rain will move into the waters
after midnight tonight and into the pre-dawn hours on Saturday.

Saturday/Saturday night...SCA conditions. Showers/tstms
Saturday and Saturday evening.
Sunday/Sunday night...sub-SCA conditions. Fair.
Monday/Tue...Sub-SCA with sct showers late. Few tstms Tue.

There is a moderate risk for the development of dangerous rip
currents at NJ ocean beaches and a low risk for the development
of dangerous rip currents at DE ocean today. However, even with
a low risk...the bigger diurnal difference in the tide cycle as
we approach the date of this months new moon could mean some
rapidly changing conditions.


High astronomical tide levels are expected in association with the
new moon today. Based on the latest guidance, not expecting
widespread minor coastal flooding with the high tide cycle this
afternoon and evening. Will hold off on issuing a Coastal Flood
Advisory, as tide levels should fall just short of minor flooding


MARINE...Small Craft Advisory from noon today to 6 PM EDT Saturday for
     Small Craft Advisory from noon today to 9 PM EDT this evening
     for ANZ430-431.


Near Term...MPS
Short Term...MPS
Long Term...O`Hara
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