Alert archive / Pennsylvania / Flash Flood Warnings in 2018

Flash Flood Warning 29, NWS Philadelphia/Mount Holly

July 4, 2018Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 4, 2018, 3:22 PM EDT for Lehigh County, Northampton County, Pennsylvania. It was in force for 4 hr. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 4, 2018, 3:22 PM EDT (19:22 UTC)
Expired
Jul 4, 2018, 7:15 PM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Lehigh County, PA, Northampton County, PA

What was reported inside it

TimeReportWhereRemark
Jul 4, 4:03 PM EDTHEAVY RAIN 3.04Orefield, PA3.04 INCHES OF RAIN FELL IN 60 MINUTES.
Jul 4, 4:14 PM EDTFLASH FLOODShankweilers, PAREPORT OF A MUDSLIDE BLOCKING ONE LANE OF I-476 SOUTHBOUND AT MILE MARKER 62

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 7.4 hours before the alert went out and 233 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 2018-07-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 145 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2018-07-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 8 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
145 J/kg
Mixed-layer CIN
-205 J/kg
Mixed-layer LCL
1091 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
8 m²/s²
0-3 km storm-relative helicity
4 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

271 
WGUS51 KPHI 041922
FFWPHI
PAC077-095-042315-
/O.NEW.KPHI.FF.W.0029.180704T1922Z-180704T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
322 PM EDT WED JUL 4 2018

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Central Lehigh County in eastern Pennsylvania...
  West central Northampton County in eastern Pennsylvania...

* Until 715 PM EDT.

* At 321 PM EDT, Doppler radar and automated rain gauges indicated
  thunderstorms producing heavy rain across the warned area. Up to 
  one and a half inches of rain has already fallen in as little as 
  twenty minutes. Flash flooding is expected to begin shortly in the 
  areas of heaviest rain.

* Some locations that could experience flooding include...
  Allentown, Bethlehem, Northampton, Slatington, Walnutport, Neffs,
  Coffeetown, New Tripoli, Jordan Valley, Beersville, Emerald,
  Schnecksville, Claussville, Catasauqua, Coplay, North Catasauqua,
  Fullerton and Hokendauqua.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around...don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Please report flooding to your local law enforcement agency when you
can do so safely.

&&

LAT...LON 4076 7569 4076 7542 4062 7542 4055 7557
      4056 7570 4062 7580

$$

CMS
2 follow-up statements
856 
WGUS71 KPHI 042100
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
500 PM EDT WED JUL 4 2018

PAC077-095-042315-
/O.CON.KPHI.FF.W.0029.000000T0000Z-180704T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lehigh PA-Northampton PA-
500 PM EDT WED JUL 4 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 715 PM EDT FOR
CENTRAL LEHIGH AND WEST CENTRAL NORTHAMPTON COUNTIES...

At 459 PM EDT, gauge reports indicated thunderstorms produced up to 
three inches of rain in the past couple of hours. A mudslide was 
reported on Interstate 476 as a result of the heavy rainfall. Though 
the heaviest rainfall is beginning to diminish, runoff will continue 
to cause problems for the next couple of hours.

Some locations that could experience flooding include...
Allentown, Bethlehem, Northampton, Slatington, Walnutport, Neffs,
Coffeetown, New Tripoli, Jordan Valley, Beersville, Emerald,
Schnecksville, Claussville, Catasauqua, Coplay, North Catasauqua,
Fullerton and Hokendauqua.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around...don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Please report flooding to your local law enforcement agency when you
can do so safely.

&&

LAT...LON 4076 7569 4076 7542 4062 7542 4055 7557
      4056 7570 4062 7580

$$

CMS
981 
WGUS71 KPHI 042309
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
709 PM EDT WED JUL 4 2018

PAC077-095-042318-
/O.EXP.KPHI.FF.W.0029.000000T0000Z-180704T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lehigh PA-Northampton PA-
709 PM EDT WED JUL 4 2018

...THE FLASH FLOOD WARNING FOR CENTRAL LEHIGH AND WEST CENTRAL
NORTHAMPTON COUNTIES WILL EXPIRE AT 715 PM EDT...

The heaviest ran has ended. However, residual runoff issues remain. 
A flood advisory will be issued to replace the flash flood warning 
shortly. Please continue to heed any remaining road closures.

LAT...LON 4076 7569 4076 7542 4062 7542 4055 7557
      4056 7570 4062 7580

$$

CMS

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 4, 9:33 AM EDTAreal Flood AdvisoryPHICarbon, Monroe98 min
Jul 4, 2:55 PM EDTSpecial Weather StatementPHILehigh35 min
Jul 4, 3:09 PM EDTAreal Flood AdvisoryPHILehigh, Northampton4 hr
Jul 4, 3:32 PM EDTSpecial Weather StatementPHILehigh, Northampton28 min
Jul 4, 3:40 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh, Northampton50 min
Jul 4, 3:56 PM EDTSpecial Weather StatementPHILebanon34 min
Jul 4, 3:59 PM EDTAreal Flood AdvisoryPHILehigh, Northampton4 hr
Jul 4, 4:20 PM EDTSpecial Weather StatementPHICarbon25 min
Jul 4, 4:25 PM EDTAreal Flood AdvisoryPHIBerks, Lehigh4 hr
Jul 4, 4:28 PM EDTAreal Flood AdvisoryPHICarbon, Lehigh, Monroe, Northampton4 hr
Jul 4, 4:28 PM EDTSpecial Weather StatementPHILehigh, Northampton32 min
Jul 4, 4:34 PM EDTSpecial Weather StatementPHIBerks56 min
Jul 4, 4:56 PM EDTSpecial Weather StatementPHICarbon49 min
Jul 4, 5:46 PM EDTSpecial Weather StatementPHIBerks29 min
Jul 4, 6:13 PM EDTSpecial Weather StatementPHIBucks, Montgomery32 min
Jul 4, 6:15 PM EDTSpecial Weather StatementPHIBerks45 min
Jul 4, 6:20 PM EDTFlash Flood WarningPHIBerks4 hr
Jul 4, 6:32 PM EDTSpecial Weather StatementPHIChester28 min
Jul 4, 7:00 PM EDTSpecial Weather StatementPHIDelaware, Montgomery, Philadelphia30 min
Jul 4, 7:07 PM EDTSpecial Weather StatementPHILebanon23 min
Jul 4, 7:13 PM EDTAreal Flood AdvisoryPHILehigh, Northampton3 hr
Jul 4, 7:18 PM EDTAreal Flood AdvisoryPHIBerks, Chester, Delaware, Montgomery, Philadelphia3 hr
Jul 4, 7:32 PM EDTSpecial Weather StatementPHIMontgomery43 min

Nearby

Flash Flood Warnings in Pennsylvania, 2018Every flash flood warning in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive.