Alert archive / New Jersey / Areal Flood Advisories in 2017

Areal Flood Advisory 74, NWS Philadelphia/Mount Holly

July 7, 20174 counties in New Jersey

NWS Philadelphia/Mount Holly issued this areal flood advisory at Jul 7, 2017, 9:51 AM EDT for 4 counties in New Jersey. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Jul 7, 2017, 9:51 AM EDT (13:51 UTC)
Expired
Jul 7, 2017, 12:45 PM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Hunterdon County, NJ, Middlesex County, NJ, Morris County, NJ, Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 76 km from the middle of the area, began a volume at 13:52 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, 1.9 hours before the alert went out and 151 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 2017-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 163 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 2017-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 square meters per square second.193958Sfc1 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
163 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
496 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
11 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 Jul 7, 6:57 AM EDT, 2 hours 54 minutes earlier.

Area forecast discussion, Jul 7, 6:57 AM EDT, 2 hours 54 minutes before
Area Forecast Discussion
National Weather Service Mount Holly NJ
657 AM EDT Fri Jul 7 2017

.SYNOPSIS...
An area of low pressure will move to our northeast today. A
cold front is expected to move across the area on Saturday. High
pressure is forecast to build just to our south on Sunday. A
cold front may wash out as it approaches the east coast Sunday
night into Monday, before a stronger front approaches Tuesday
night into Wednesday. This front may stall near the area through
the end of the week with a couple of low pressure systems
moving eastward toward the east coast along the boundary.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The line of showers has been persistent over the Lehigh Valley,
NW NJ, and southern Poconos. Although hourly rates haven't been
nearly as high as what we saw with the storms yesterday, the
persistent moderate to heavy rain could be enough for flooding
for portions of this area. The mid level short wave trough
will continue to propagate closer to the region (as of 7 AM,
the trough axis at 500 mb was moving through western PA).

Once the trough axis shifts east of the region mid day, dry air
advection will begin, leading to dropping PW values.
Additionally, we should see a lull in any synoptic scale lift.
However, breaks in the clouds/differential heating could be
enough for isolated to scattered showers and thunderstorms
through the afternoon.

For areas that aren't seeing widespread showers this morning
(primarily along the Coastal Plains of NJ), areas of fog have
already developed and are expected to persist through mid
morning. However, winds shifting out of the north and
eventually west should limit the development of dense fog.

Expect breaks in the clouds as well once the trough moves east
of the region. As a result, went slightly above guidance for
highs today. Expect highs to range from the upper 70s to upper
80s, however, the highs may come later than usual.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
Very late tonight, the next round of showers and thunderstorms
should approach from the west in advance of the cold front. If
the clouds and showers are later in arriving (after day break),
then patchy fog may develop very late tonight.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
After a relatively quiet weekend, an active week may be in
store.

A cold front is forecast move across the area on Saturday.
While moisture decreases across the area, especially Saturday,
PW values will remain around or slightly above 1.5 inches
overnight into early Saturday. There is also a couple of short
waves forecast to move across the area during the day Saturday.
So there will remain a chance of showers and thunderstorms into
Saturday. As PW value drop during the afternoon and overnight
Saturday, precipitation chances will diminish.

High pressure is forecast to briefly build to our south Sunday
into Sunday night which will bring dry conditions to the area.
Sunday will be the best day of the long term forecast with dry
conditions, seasonable temperatures and lower humidity.

The high moves offshore and weakens sunday night into Monday as
a cold front approaches from the northwest, although this front
is expected to wash out before reaching the area. However, PW
values increase again by later Monday into Monday night. As a
couple of short wave/vorticity impulses slide across the area, a
few isolated/scattered shower may develop.

Another frontal boundary is forecast to approach the area on
Tuesday into Wednesday, and may stall near the area through the
end of the week. As the front stalls near the area, a couple of
low pressure systems could move eastward along the boundary and
affect the area. Meanwhile, several short wave/vorticity
impulses will move across the area as well through the period.
This could lead to an increase in precipitation chances for the
middle to end of the week. PW values increase again to 1.5-1.75
inches, and very well could top 2 inches, so periods of heavy
rain would be possible again.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

IFR conditions are expected to persist through much of the
morning hours. Should see most locations improve to VFR near or
after 18Z. However, there may be a brief period of fog after
06Z which may once again result in MVFR or even IFR conditions.
There will be a chance for thunderstorms through out the TAF
period, but the coverage is expected to be too limited to
mention in the TAFs at this time.

Wind direction will be variable shifting from northwesterly to
southwesterly through the day. Wind speeds though are expected
to remain near or below 10 kt.

OUTLOOK...

Saturday...Generally VFR expected. Slight chance of showers. Gusty
westerly winds 15-20 knots.

Saturday night-Sunday night...Generally VFR expected.

Monday-Tuesday...Generally VFR expected with a slight chance of
showers and thunderstorms. Any showers or thunderstorms could
temporarily lead to lower conditions

&&

.MARINE...
Winds and seas are expected to stay below SCA criteria today
and tonight. Gusts near or just above 20 kt will be possible
tonight, but are expected to stay below 25 kt.

Areas of fog will be possible through mid morning. A shift in
the wind direction should limit the development of dense fog
though.

Outlook...
Saturday-Tuesday...Generally sub Small Craft Advisory
conditions expected. Winds may gust around 20 knots at times
through the period, and seas will be the highest Saturday into
Sunday around 3-4 feet.

RIP CURRENTS...

The risk for the formation of dangerous rip currents is
expected to be low today.

&&

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

&&

Synopsis...Robertson
Near Term...Johnson
Short Term...Johnson
Long Term...Robertson
Aviation...Johnson/Robertson
Marine...Johnson/Robertson
Hazardous weather outlook, Jul 7, 3:30 AM EDT, 6 hours 21 minutes before
Hazardous Weather Outlook
National Weather Service Mount Holly NJ
330 AM EDT Fri Jul 7 2017

DEZ001>004-MDZ008-012-015-019-020-NJZ001-007>010-012>027-PAZ054-055-
060>062-070-071-101>106-080730-
New Castle-Kent-Inland Sussex-Delaware Beaches-Cecil-Kent MD-
Queen Annes-Talbot-Caroline-Sussex-Warren-Morris-Hunterdon-Somerset-
Middlesex-Western Monmouth-Eastern Monmouth-Mercer-Salem-Gloucester-
Camden-Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Atlantic Coastal Cape May-Coastal Atlantic-Coastal Ocean-
Southeastern Burlington-Carbon-Monroe-Berks-Lehigh-Northampton-
Delaware-Philadelphia-Western Chester-Eastern Chester-
Western Montgomery-Eastern Montgomery-Upper Bucks-Lower Bucks-
330 AM EDT Fri Jul 7 2017

This Hazardous Weather Outlook is for central Delaware, northern
Delaware, southern Delaware, northeast Maryland, central New
Jersey, northern New Jersey, northwest New Jersey, southern New
Jersey, east central Pennsylvania, northeast Pennsylvania and
southeast Pennsylvania.

.DAY ONE...Today and Tonight.

Showers and thunderstorms today will be capable of producing heavy
rain, leading to poor drainage flooding.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

ANZ430-431-450>455-080730-
Delaware Bay waters north of East Point NJ to Slaughter Beach DE-
Delaware Bay waters south of East Point NJ to Slaughter Beach DE-
Coastal waters from Sandy Hook to Manasquan Inlet NJ out 20 nm-
Coastal waters from Manasquan Inlet to Little Egg Inlet NJ out 20 nm-
Coastal waters from Little Egg Inlet to Great Egg Inlet NJ out 20 nm-
Coastal waters from Great Egg Inlet to Cape May NJ out 20 nm-
Coastal waters from Cape May NJ to Cape Henlopen DE out 20 nm-
Coastal waters from Cape Henlopen to Fenwick Island DE out 20 nm-
330 AM EDT Fri Jul 7 2017

This Hazardous Weather Outlook is for Atlantic coastal waters and
Delaware Bay Waters.

.DAY ONE...Today and Tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

In the hours before

Local storm report, Jul 7, 8:58 AM EDT, 53 minutes before
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Local storm report, Jul 7, 9:32 AM EDT, 19 minutes before
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Local storm report, Jul 7, 9:41 AM EDT, 10 minutes before
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Local storm report, Jul 7, 9:42 AM EDT, 9 minutes before
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Local storm report, Jul 7, 9:44 AM EDT, 7 minutes before
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
944 AM EDT FRI JUL 07 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0622 AM     HEAVY RAIN       LEHIGHTON               40.83N  75.72W
07/07/2017  M2.36 INCH       CARBON             PA   MESONET

0626 AM     HEAVY RAIN       LEHIGH TWP              40.75N  75.54W
07/07/2017  M2.53 INCH       NORTHAMPTON        PA   MESONET

0700 AM     HEAVY RAIN       2 SW CLAYTON            39.28N  75.66W
07/07/2017  M2.32 INCH       KENT               DE   COCORAHS

            24 HOUR RAINFALL.

0700 AM     HEAVY RAIN       3 WSW LEHIGHTON         40.81N  75.77W
07/07/2017  M3.20 INCH       CARBON             PA   COCORAHS

            24 HOUR RAINFALL.

0700 AM     HEAVY RAIN       1 NNW HAMBURG           40.57N  75.99W
07/07/2017  M2.87 INCH       BERKS              PA   COCORAHS

            24 HOUR RAINFALL.

0741 AM     HEAVY RAIN       BRODHEADSVILLE          40.92N  75.40W
07/07/2017  M2.01 INCH       MONROE             PA   MESONET

0747 AM     HEAVY RAIN       SAYLORSBURG             40.90N  75.32W
07/07/2017  M2.54 INCH       MONROE             PA   MESONET

0747 AM     HEAVY RAIN       MOUNT BETHEL            40.90N  75.11W
07/07/2017  M2.29 INCH       NORTHAMPTON        PA   MESONET

0748 AM     HEAVY RAIN       BELVIDERE               40.83N  75.08W
07/07/2017  M2.38 INCH       WARREN             NJ   MESONET

0748 AM     FLOOD            NORTHAMPTON             40.69N  75.49W
07/07/2017                   NORTHAMPTON        PA   TRAINED SPOTTER

            HIGHWAY 329 NEAR QUARRY IS FLOODED... WEAVERSVILLE ROAD
            ALONG WITH THE INTERSECTION OF AIRPORT ROAD AND ORCHARD
            LANE FLOODED.

0749 AM     HEAVY RAIN       HARMONY TWP             40.75N  75.13W
07/07/2017  M2.47 INCH       WARREN             NJ   MESONET

0749 AM     HEAVY RAIN       COPELLA                 40.80N  75.37W
07/07/2017  M3.18 INCH       NORTHAMPTON        PA   MESONET

0750 AM     HEAVY RAIN       JAMESVILLE              40.74N  75.42W
07/07/2017  M3.02 INCH       NORTHAMPTON        PA   MESONET

0751 AM     HEAVY RAIN       OREFIELD                40.63N  75.58W
07/07/2017  M2.21 INCH       LEHIGH             PA   MESONET

0751 AM     HEAVY RAIN       1 W ALLENTOWN           40.59N  75.50W
07/07/2017  M2.70 INCH       LEHIGH             PA   MESONET

0752 AM     HEAVY RAIN       BETHANY BEACH           38.54N  75.07W
07/07/2017  M4.74 INCH       SUSSEX             DE   DEOS

0818 AM     FLOOD            HACKETTSTOWN            40.85N  74.83W
07/07/2017                   WARREN             NJ   TRAINED SPOTTER

            SEVERAL ROADS FLOODED INCLUDING ROUTE 46. STREAMS
            OVERFLOWING BANKS.

0822 AM     HEAVY RAIN       SLATEDALE               40.74N  75.66W
07/07/2017  M2.62 INCH       LEHIGH             PA   TRAINED SPOTTER

0843 AM     HEAVY RAIN       MARTINS CREEK           40.78N  75.19W
07/07/2017  M2.25 INCH       NORTHAMPTON        PA   COCORAHS

0855 AM     FLOOD            FORKS TWP               40.73N  75.22W
07/07/2017                   NORTHAMPTON        PA   911 CALL CENTER

            VEHICLE STUCK ON FLOODED ROADWAY WITH ONE PERSON
            TRAPPED INSIDE.

0907 AM     FLOOD            BETHLEHEM               40.63N  75.37W
07/07/2017                   NORTHAMPTON        PA   911 CALL CENTER

            ROUTE 378 SOUTH FLOODED IN SPOTS.

0932 AM     HEAVY RAIN       WHITE TWP               40.83N  75.03W
07/07/2017  M3.00 INCH       WARREN             NJ   COCORAHS

&&

EVENT NUMBER PHI1700925 PHI1700926 PHI1700946 PHI1700947 PHI1700948
PHI1700936 PHI1700937 PHI1700938 PHI1700939 PHI1700950 PHI1700940
PHI1700941 PHI1700942 PHI1700943 PHI1700944 PHI1700945 PHI1700949
PHI1700951 PHI1700952 PHI1700954 PHI1700955 PHI1700953

GAINES
Local storm report, Jul 7, 9:51 AM EDT, 0 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
951 AM EDT FRI JUL 07 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0939 AM     FLOOD            EASTON                  40.69N  75.22W
07/07/2017                   NORTHAMPTON        PA   911 CALL CENTER

            SEVERAL ROADS FLOODED INCLUDING CENTER... VALLEY AND
            LINE STREETS.

&&

EVENT NUMBER PHI1700956

GAINES

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 7, 4:37 AM EDTAreal Flood AdvisoryPHIHunterdon, Morris, Sussex, Warren4 hr
Jul 7, 7:00 AM EDTAreal Flood WarningPHIWarren6 hr
Jul 7, 8:15 AM EDTAreal Flood WarningPHIHunterdon, Morris, Sussex, Warren4 hr
Jul 7, 8:25 AM EDTSpecial Weather StatementPHIMorris35 min
Jul 7, 12:11 PM EDTAreal Flood WarningPHIHunterdon, Morris, Somerset, Sussex, Warren4 hr
Jul 7, 1:00 PM EDTAreal Flood WarningPHIWarren4 hr
Jul 7, 7:30 PM EDTSpecial Weather StatementPHIDelaware30 min
Jul 7, 7:43 PM EDTSpecial Weather StatementPHIPhiladelphia62 min

Nearby

Areal Flood Advisories in New Jersey, 2017Every areal flood advisory in 2017

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.