Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 312007
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
407 PM EDT TUE MAY 31 2016

.SYNOPSIS...
A cold front has weakened and pushed offshore today, and a secondary
backdoor front will push southward across the area tonight into
Wednesday morning. Our area will be on the southern edge of high
pressure located across eastern Canada through early Thursday. A
cold front will move across the area Friday. An area of low pressure
and associated frontal boundaries will move across the Great Lakes
region Saturday into Sunday, and across the Northeast Monday into
Tuesday, bringing unsettled weather to our area early next week.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
A few sct showers have developed across srn Delaware over the
past hour. The op models from earlier had this development fcst
and we will keep the slgt chc mention in the grids for the early
evening. Skies are partly to mostly sunny elsewhere and
temperatures are a little above normal for late May. Highs have
reached the low/mid 80s in most areas...cooler at the shore. A sea
breeze has developed and will push inland through the afternoon.
It may reach the Delaware valley before mixing out around dusk.


&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
The high pressure to the north of the area Wednesday morning will
move into eastern Canada. The will place our region in the erly
flow on the south side of the high. This should provide some fair
weather for Wednesday with cooler temperatures (compared to
Tuesday). Highs will be in the upper 70s to low 80s in most areas.
Sky cover will be mostly sunny early with some clouds developing
late across the srn/wrn areas. We have included a small chc for a
shower across the Delmarva and se PA areas. Some of the
operational models show some qpf output.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Our area will continue to be on the far southern edge of an area of
high pressure that will be residing across central and eastern
Canada Wednesday night through Thursday. Mostly dry conditions are
expected, although an isolated shower could be possible overnight
Wednesday into early Thursday as a weak vorticity impulse slides
across the area and could interact with some increased moisture
within the return flow at the surface. Another vorticity impulse is
forecast to approach the area late in the day and overnight, which
could bring additional isolated showers by the afternoon. However,
there will be a greater potential for showers overnight as this
short wave/vorticity impulse moves across the area.

On Friday, we expect a cold front to move across the area from west
to east as an area of low pressure moves across eastern Canada.
there will be an increase in instability, along with PW values
reaching 1.75 inches. Therefore, we can expect scattered showers and
thunderstorms to develop ahead of and along the frontal boundary
during the day. The flow is not very strong, so any slow moving
storms could produce some high amounts. But the front should still
be fairly progressive, so no widespread flooding is expected at this
time. The front will slowly make its way offshore Friday night, so
there could still be some lingering showers and thunderstorms during
the evening and early in the night Friday. All showers should be
ending overnight.

There could be a dry period Saturday as high pressure across central
Canada tries to nose its way down across the area. It would not be
surprising if an isolated shower were to occur, but we`ll keep this
out of the forecast for now as the chances are small at this time.

Unsettled weather returns for Sunday through Monday as an area of
low pressure will be moving through the Great Lakes region and into
the northeast. A warm front should be lifting across the area late
Sunday into Sunday night, then a cold front will move across the
area late Sunday night into early Monday. A period of showers and
isolated thunderstorms should move across the area through this time
period. PW values approach 2 inches during this time, so there could
be some periods of heavy rainfall possible.

There will continue to be a chance of showers Monday night into
Tuesday as the low slowly pinwheels to our north through New
England, especially during the afternoon Tuesday as a secondary
surface trough/frontal boundary crosses the area.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG,KMIV, KACY AND SURROUNDING AREAS.

VFR conditions have returned to all of the terminals as of the mid-
afternoon. The CIGS at KILG/KMIV and KACY were the last sites to
mix out due to the abundance of the low level moisture and the
former front dissipating over the area. VFR conditions will last into
the evening before more fog develops overnight. I have kept the
mention of fog across KRDG/KABE a little more uncertain with only
tempo groups and more certain at the other sites with an attempt at
categories and timing. Could be some low conditions where the dew
points were higher today (KMIV/KACY). Winds have been challenging
with NE winds early this afternoon and trending more light and
variable lately. A sea breeze will probably bring some E/SE winds to
KACY/KMIV/KILG shortly. The sea breeze may make it to KPHL/KPNE
towards dusk. Light winds tonight and E/SE winds 5 to 10 knots Wed
morning.

OUTLOOK...

Wednesday night-Thursday...Generally VFR inland. Lower clouds
and/or fog possible near the coast may push inland. Mostly light
east to southeast flow.

Thursday night...MVFR ceilings may develop across the area, with
showers possibly developing from west to east.

Friday-Friday night...MVFR and/or IFR ceilings possible. Showers
and thunderstorms possible, especially later in the day. Improving
conditions later in the evening and overnight.

Saturday...Generally VFR.

Saturday night-Sunday...Diminishing conditions, possible becoming
IFR by Sunday morning. Rainfall becoming more widespread Sunday.
Gusty southeast winds possible Sunday.

&&

.MARINE...
We have dropped the dense fog advisory with the latest vis
satellite pics showing that the fog has diminished for now. There
could be more later tonight...so areas of fog (not dense) was placed
in the grids for overnight. Winds will be mostly onshore with erly
or serly up Delaware Bay. Winds speeds mostly in the 10 knot range
for most areas. some gusts up to 20 knots possible across the
Delaware bay late this afternoon and into the evening. Sct showers
possible over the Delaware and Srn NJ Coastal waters and Del bay into
the evening.

OUTLOOK...

Wednesday-Sunday...Conditions forecast to be below Small Craft
Advisory levels through the period. Winds could gust around 20
knots at times. Generally east to southeasterly winds, except
west to northwest briefly behind frontal boundary passage Friday
night.

&&

.TIDES/COASTAL FLOODING...
Onshore flow is expected to develop on Wednesday and continue
into Friday. We will need to monitor the possibility of minor
tidal flooding at times of high tide along the coast late this
week owing to the persistent onshore flow and the approaching new
moon this Saturday.

&&

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

&&

$$
Synopsis...Robertson
Near Term...O`Hara
Short Term...O`Hara
Long Term...Robertson/Borowski
Aviation...Robertson/O`Hara
Marine...Robertson/O`Hara
Tides/Coastal Flooding...



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