Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 231909
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
309 PM EDT Tue May 23 2017

.SYNOPSIS...
A low pressure system will pass to the south and east of our
area tonight, followed by weak high pressure for Wednesday.
Another system develops over the Ohio Valley affecting the mid
Atlantic states Wednesday night through early Friday. Weak high
pressure returns for Saturday with yet another low pressure
forecast to affect the region for Sunday or Monday.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
An email briefing with a coastal flood graphic will post by 315 PM
this afternoon. It highlights tidal inundation flood potential
for the Wed-Thu evening high tide cycles on the Atlantic coasts
of DE and NJ. The next briefing of either a full scale package
or email will post around 3 PM Wednesday, incorporating not
only the minor to possibly moderate coastal flood threat and
associated products but also a possible QLCS event for se PA/
the Delmarva/s NJ late Thursday.

Isolated showers may be drying into sprinkles as this is
written near and sw of PHL. Otherwise sprinkles are departing
se DE.

Tonight: Low pressure off the mid Atlantic coast will continue
to slide northeast, with showers along the coasts but chancey
for e PA/nNJ late tonight. northeast wind.

This forecast was based on a 50 50 blend of the 12z/23 GFS/NAM.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
Wednesday...scattered leftover showers possible in the morning
but it should dry out and be a decent afternoon everywhere.
Northeast wind becomes southeast in the afternoon.

This forecast was based on a 50 50 blend of the 12z/23 GFS/NAM.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Wednesday night and Thursday...Low pressure over the Ohio Valley
will move northeast on Thursday. Another low forms along the cold
frontal boundary as it nears our area, and will cross our area later
Thursday.

Rain will start to overspread the region late Wednesday night and
continue through much of Thursday. Marginal instability is noted and
we continue to mention the chance for convection across the area.
With PWAT`s once again rising up around 1.5-1.7 inches, we have the
potential for moderate to heavy rain. With the wet period we have
had of late, we will need to continue to monitor any heavy rain
threat.

Friday...Some showers possible Friday, mainly early and across the
northern half of our forecast area. Overall, it should start to
clear out across our area. Although, a slight cool down can be
expected in the westerly flow.

Saturday...High pressure will build in for Saturday and it should be
a great start to the holiday weekend. A shortwave moves through the
mid levels and across our area Saturday afternoon/evening. This may
spark off a few light showers, mainly across the northern areas.

Sunday and Monday...The rest of the holiday weekend looks unsettled
as another low pressure system develops and heads towards the Mid-
Atlantic. A chance for some showers and/or thunderstorms will be
possible. A cooler day on Sunday with highs only into the low to mid-
70s but warming is expected for Monday, with highs into the upper
70s to lower 80s.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

Through tonight...VFR lowering CIGS with potential MVFR Conds
in showers KACY/KMIV late at night while any period of showers
elsewhere should not lower conditions to MVFR. Northeast wind,
may gust 20 kt ACY.

Wednesday...VFR cigs inn the morning and then sct-bkn aoa 4000
ft in the aftn. MVFR/IFR conditions possible early in the day,
mainly at KMIV/KACY. northeast wind become southeast in the
afternoon. max gusts 15 kt.

Outlook...

Wednesday night and Thursday...Deteriorating conditions as rain
moves into the area. VFR conditions with periods of MVFR/IFR in
showers/thunderstorms. Easterly winds around 10 to 15 knots
becoming south to southeast around 10 knots or less late.

Friday...Improving conditions with a return to VFR expected. Showers
possible early. West winds around 10 to 15 knots.

Saturday...Mainly VFR conditions expected. West to southwest winds.

&&

.MARINE...
SCA continues DE Atlc waters late tonight and now extended
through the day tomorrow.

SCA added for the NJ waters, primarily there for hazardous 5 ft
seas. There is a chance the guidance might be a foot too high
but I had to issue since our fcst is for 4 to 6 ft.

Outlook...

Thursday and Friday...Seas are expected to build in the
prolonged easterly flow. Small Craft Advisory will likely be
needed. Improving conditions on the waters through Friday as
seas start to subside and winds diminish.

Saturday...Both winds and waves are expected to stay below SCA
criteria.

&&

.HYDROLOGY...
After rain amounts over 3 inches in some places across south
Jersey yesterday, levels for many creek and rivers on the
coastal Plains were slowing their rises or receding. At this
time, all remain below bankfull and flood stages, but we continue
to monitor this area. Models have trended further southeast and
later with heavy rain today. Thus, though these areas will
likely see additional rain late today, we are expecting
generally light rain amounts (near or below one quarter inch).

A wet pattern looks to continue for much of the week. The next
period of heavy rain could come as early as Wednesday night into
Thursday.

&&

.TIDES/COASTAL FLOODING...
CFW for minor coastal flooding issued for the Wednesday evening
high tide cycle. A CF Watch may be needed for the Thursday evening
high tide cycle for Monmouth/Ocean and Middlesex counties but
that wont be issued, if at all, until sometime Wednesday.

This afternoons issuance is also appended to a blast email for
Em`s including an image with a followup Wednesday around or
shortly after 3 Pm.

Some of the highest astronomical tides of the year are occuring
late this week. The new moon cycle on Thursday, combined with a
possible prolonged easterly flow, we will probably see some of
our coastal sites exceed minor tidal flooding levels during the
Wednesday and Thursday evening tide cycles. There is also a
small chance that we could reach moderate levels in a few spots.

&&

.CLIMATE...
ACY is #6 wettest May on record with its 6.07. The record there for
May is 8.80 set in 1948....POR back to 1874.

Monthly avg temps should end up within .7 degrees of where they
are now, possibly edging on the warmer side of the current departures
as seen in our climate data ending the 22nd.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...Coastal Flood Advisory from 6 PM Wednesday to midnight EDT
     Wednesday night for NJZ012>014-020>027.
DE...Coastal Flood Advisory from 6 PM Wednesday to midnight EDT
     Wednesday night for DEZ002>004.
MD...None.
MARINE...Small Craft Advisory from 8 AM to 4 PM EDT Wednesday for
     ANZ450>453.
     Small Craft Advisory from midnight tonight to noon EDT
     Wednesday for ANZ454-455.

&&

$$
Synopsis...Meola
Near Term...Drag 307
Short Term...Drag 307
Long Term...Meola
Aviation...Drag/Meola 307
Marine...Drag/Meola 307
Hydrology...307
Tides/Coastal Flooding...307
Climate...



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