Alert archive / New Jersey / Areal Flood Advisories in 2016

Areal Flood Advisory 133, NWS Philadelphia/Mount Holly

August 20, 2016Ocean County, New Jersey

NWS Philadelphia/Mount Holly issued this areal flood advisory at Aug 20, 2016, 3:45 PM EDT for Ocean County, New Jersey. It was in force for 2 hr.

The area

The counties it named.

The facts

Issued
Aug 20, 2016, 3:45 PM EDT (19:45 UTC)
Expired
Aug 20, 2016, 5:45 PM EDT
In force
2 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

County Ocean County, NJ

The radar

The Philadelphia radar (KDIX), 16 km from the middle of the area, began a volume at 19:47 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 7.8 hours before the alert went out and 162 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Brookhaven, NY at 12:00Z on 2016-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 957 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2016-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -13 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
957 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
652 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
-13 m²/s²
0-3 km storm-relative helicity
12 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal flood advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Philadelphia/Mount Holly wrote its last area forecast discussion before this areal flood advisory went out at Aug 20, 11:46 AM EDT, 3 hours 59 minutes earlier.

Area forecast discussion, Aug 20, 11:46 AM EDT, 3 hours 59 minutes before
Area Forecast Discussion
National Weather Service Mount Holly NJ
1146 AM EDT SAT AUG 20 2016

.SYNOPSIS...
Weak high pressure is forecast to influence our weather through tonight.
A strong cold front is expected to approach from the west on Sunday
and it should pass through eastern Pennsylvania, northeastern Maryland,
Delaware and New Jersey on Sunday evening. High pressure is anticipated
to follow and it should build across our region during the period
from Monday through Thursday. Another cold front is forecast to approach
from the northwest on Friday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Daytime heating and the weak front to the north have created
deeper Cu and sct showers across NE NJ and more widespread
activity (outside of our CWA) across Long island NY. We will
continue to advertise the possibility for the SCT showers in the
zones and have updated POPs accordingly. Few adjustments in Temps
were made along the I-95 corridor with a bit higher numbers
needed, Elsewhere, fcst seem on target.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
Tonight, the backdoor cold front will likely decay with the
frontal system to the south lifting north as a warm front. Our
region will still see a direct southeast flow into the region
channeling in plenty of moisture. Temperatures will be slow to
fall for most of us with a few more clouds around. Still lows
should fall below 70 in most spots, low 70's for PHL. For now, the
forecast remains precipitation free despite a warm airmass in
place as any triggers for showers and thunderstorms are still
south and west of the region.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Sunday continues to appear as though it will be an active weather
day in our region. We will mention clouds and a chance of showers
during the morning hours as warm moist air continues to advect
into our region.

A strong cold front will approach from the west on Sunday
afternoon. The lift ahead of the system along with increasing
instability will result in showers and thunderstorms. The forecast
wind profiles ahead of the front suggest the potential for some
organized storms. The winds aloft should begin to veer during the
afternoon and speeds will likely be on the increase. The Storm
Prediction Center has placed much of our forecast area under a
marginal risk for severe weather.

Also, a narrow band of precipitable water values in the 2.3 to
2.4 inch range is expected to be drawn northward and into our
region ahead of the front. The developing convection should be
able to tap into the abundant moisture and there is the potential
for heavy rain along with flooding on small streams and in areas
of poor drainage.

The most significant of the weather is anticipated to move from
west to east across our forecast area ahead of the cold front,
between about 4:00 PM and 10:00 PM. The actual front is expected
to arrive in eastern Pennsylvania during the early evening and it
should pass off the coast before midnight.

High temperatures on Sunday should be mainly in the 80s with dew
point readings favoring the lower 70s.

Once the cold front passes, there will be a noticeable change in
air mass. High pressure is expected to build from the Ohio River
Valley on Monday to our region on Tuesday. The center of the high
is anticipated to pass off the coast on Wednesday.

Maximum temperatures during the period from Monday through
Wednesday are forecast to favor the lower and middle 80s in our
region, with locations in the north not getting out of the 70s,
especially on Monday and Tuesday. Dew point readings should drop
into the 50s. Overnight lows will be in the 50s and 60s.

We are expecting to be in the return flow on the back side of the
high for Thursday and Friday. As a result, there should be a
gradual increase in heat and humidity at that time. We will
mention a chance of showers and thunderstorms on Friday with a
cold front anticipated to approach from the northwest.

&&

.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Winds will stay under 10 knots from the southeast throughout much
of the day. A brief isolated shower or thunderstorm can not be
ruled out, but given the small chance of impact at a TAF site, no
inclusion in the 06z TAFS. VFR conditions for the afternoon and
evening hours today.

OUTLOOK...
Sunday and Sunday evening...Deteriorating conditions are expected
as a strong cold front approaches from the west. Showers and
thunderstorms with heavy rain and gusty winds are anticipated
during the afternoon and evening hours.

Sunday night...Conditions improving overnight as showers and
thunderstorms pass off the coast and move out to sea.

Monday through Wednesday...Mainly VFR.

&&

.MARINE...
Wave heights are expected to continue to be around one foot for
most of today likely increasing closer to two feet tonight. Winds
will continue to be from the east and southeast around 10 knots
through tonight. No SCA headlines.

OUTLOOK...
Sunday and Sunday night...No marine headlines are anticipated.

Monday and Monday night...Northwest wind gusts may approach 25
knots.

Tuesday through Wednesday...No marine headlines are anticipated.

RIP CURRENTS...
The rip current risk is expected to be low today. However, if
southeast winds this afternoon increase a bit more than expected
at the shore then some beaches could see conditions that match the
moderate risk category.

The probable risk for the development of dangerous rip currents
on Sunday is low approaching moderate.

&&

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

&&

Synopsis...Iovino
Near Term...Po
Short Term...Gaines
Long Term...Iovino
Aviation...Gaines/Iovino/Po
Marine...Gaines/Iovino
Hazardous weather outlook, Aug 20, 1:55 PM EDT, 1 hour 50 minutes before
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The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 20, 3:02 PM EDTAreal Flood AdvisoryPHIOcean3 hr
Aug 20, 3:38 PM EDTAreal Flood AdvisoryPHICumberland, Salem52 min
Aug 20, 4:07 PM EDTSmall Craft AdvisoryPHI47 hr
Aug 20, 4:21 PM EDTAreal Flood AdvisoryPHIMiddlesex54 min
Aug 20, 5:39 PM EDTAreal Flood AdvisoryPHICamden51 min

Nearby

Areal Flood Advisories in New Jersey, 2016Every areal flood advisory in 2016

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.