Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 292210
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
610 PM EDT FRI JUL 29 2016

.SYNOPSIS...
Scattered showers and thunderstorms with locally heavy rainfall
will re-develop Saturday afternoon and linger into Monday with a
frontal boundary hung up across the mid Atlantic States. High
pressure will then bring mainly dry and less humid weather
for the remainder of the next work week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
6 PM ESTF: modified the fcst for band of heavy showers moving
south into northern NJ, which may remain alive until dissipating
around 9 PM.

Then dry overnight.

Winds will be continuing to diminish and shift to southerly late
tonight. This, combined with the recent heavy rainfall across portions
of the region means we could see patchy fog especially across the
axis of heaviest precip in northern Delmarva and the Pine Barrens.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
The upper level trough becomes more defined as it moves closer to
the region. As a result, should see an area of precipitation move
into the region (exact timing is uncertain by the higher chances
look to be in the afternoon). As far as hazards, the primary hazard
appears to be heavy rain. Precipitable water values are well above
normal, and storm motions look to be quite slow (<15 kts) as the
flow is weak. However, with limited focus for surface convergence
(at least over our immediate area), not confident that there will be
a widespread flooding threat. Thus, not planning to issue a flash
flood watch at this time.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Highlights...

* Scattered showers and thunderstorms Saturday night/Sunday with the
  potential for heavy rainfall and a very localized flood threat

* Scattered showers/thunderstorms linger Monday, otherwise much of
  the next work week will be dry and less humid

Details...

Saturday night and Sunday...

A couple of additional shortwaves will move across our region along
with a frontal boundary in the vicinity.  The result will be periods
of scattered showers and thunderstorms Saturday night into Sunday.
Specific timing is uncertain at this point, but Pwats of 2+ inches
will bring the potential for locally heavy rainfall.  While any
flood threat looks very localized, weak low level wind fields may
result in slow movement and back building of any thunderstorms,
so that will need to be watched. Weak wind fields will also result
in a low overall risk for severe weather, but a few strong storms
can not be ruled out.

Monday...

Guidance has trended a bit slower over the past 24 hours.  Frontal
boundary will still be across our region along with another piece of
shortwave energy moving in on Monday. The result will be the
continued chance for scattered showers and thunderstorms.

Tuesday Through Friday...

Large high pressure will be building across the mid Atlantic States.
While we can not rule out a few lingering showers Tuesday, mainly
dry and less humid weather is expected through Friday.  High temps
will mainly be in the 80s for much of the next work week.

&&

.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Through 06Z, mostly VFR conditions are expected with the following
exceptions: There is a small chance (20%) that storms could develop
near or over the TAF sites through 00Z. Brief MVFR conditions and
lightning will be possible with this afternoon`s storms. Also, lower
clouds between 2000 and 3000 ft AGL have persisted at TTN, but
should scatter out shortly.

Between 06 and 12Z: Patchy light fog is possible, generally for TAF
sites outside of the Philly metro. MVFR visibilities are possible.

After 12Z: rain showers with embedded thunderstorms are expected to
move towards the region from west to east. Precip could begin to
move into the western TAF sites (KABE, KRDG) after 15Z and Delaware
Valley TAF sites (KPHL, KPNE, KILG, and KTTN) after 18Z.

Winds will be light through the period, but the direction will shift
from north and northeasterly currently, to southerly and
southeasterly by mid day tomorrow.


Outlook...

Saturday night through Monday...Moderate to high confidence.
VFR dominates but periods of lower conditions expected in
scattered showers and thunderstorms.

Tuesday and Wednesday...Moderate to high confidence in mainly VFR
conditions.

&&

.MARINE...
Winds and seas should remain below SCA criteria tonight and
tomorrow. Earlier gusts above 20 kts have subsided and will continue
to subside through the evening hours.

Outlook...Saturday night through Wednesday...A wave of low pressure
may result in a brief period of marginal small craft advisory seas
across our northern waters Sunday afternoon/early evening.
Otherwise, weak pressure gradient should keep winds/seas mainly
below small craft advisory thresholds through Wednesday.  Main
concern for mariners will be the threat of scattered thunderstorms
Saturday night through Monday.

Rip Currents...The probably risk for the development of dangerous
rip currents on Saturday is low.

&&

.CLIMATE...
GED: a record daily rainfall of 2.80 inches occurred for the
28th.

PHL: heading for top 10 warmest July on record. July avg temp for
PHL will be about 80.9F, 8th warmest July in the period of record
since 1874.

ACY: already is at least 7th wettest July on record with its
monthly record of 13.09 set in 1959. The por is back to 1874.
Total for the month as of the 28th: 8.35".

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.

&&

$$
Synopsis...99
Near Term...Drag/Johnson 610PM
Short Term...Johnson
Long Term...99
Aviation...Johnson/99
Marine...Johnson/99
Climate...


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