Alert archive / Pennsylvania / Flash Flood Warnings in 2018

Flash Flood Warning 50, NWS Philadelphia/Mount Holly

August 3, 2018Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 3, 2018, 10:23 PM EDT for Lehigh County, Northampton County, Pennsylvania. It was in force for 4 hr. 3 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: Aug 3, 2018, 10:23 PM EDT (02:23 UTC)
Expired: Aug 4, 2018, 2:30 AM 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

The radar

The Philadelphia radar (KDIX), 113 km from the middle of the area, began a volume at 02:26 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.

What was reported inside it

Time	Report	Where	Remark
Aug 3, 10:47 PM EDT	FLOOD	Griesemersville, PA	STREET FLOODING ON HAMILTON STREET NEAR CEDAR CREEK.
Aug 3, 11:00 PM EDT	FLOOD	Orefield, PA	FLOODING AT AND NEAR THE INTERSECTION OF OREFIELD ROAD AND COFFEETOWN ROAD.
Aug 4, 12:00 AM EDT	HEAVY RAIN 2.31	North Catasauqua, PA	DAILY RAINFALL TOTAL FOR AUGUST 3, WITH MOST OCCURRING WITHIN A TWO-HOUR PERIOD.

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 00:00Z, 2.4 hours before the alert went out and 207 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1302 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 561 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 12 m²/s²
0-3 km storm-relative helicity: 32 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted.

744 
WGUS51 KPHI 040223
FFWPHI
PAC077-095-040630-
/O.NEW.KPHI.FF.W.0050.180804T0223Z-180804T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1023 PM EDT FRI AUG 3 2018

The National Weather Service in Mount Holly NJ has issued a

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

* Until 230 AM EDT.

* At 1022 PM EDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to two inches of rain have
  already fallen. Flash flooding is expected to begin shortly in the
  areas of heaviest rain.

* Some locations that could experience flooding include...
  Allentown, Easton, Bethlehem, Forks, Emmaus, Northampton, Wilson,
  Hellertown, Nazareth, Slatington, Wind Gap, Bath, Walnutport,
  Belfast, West Easton, Tatamy, Steuben, Glendon, Neffs and
  Coffeetown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

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

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 4082 7548 4083 7538 4087 7528 4076 7518
      4074 7519 4073 7518 4068 7520 4068 7517
      4065 7520 4062 7519 4061 7520 4056 7530
      4042 7549 4064 7584

$$

Meola

1 follow-up statement

948 
WGUS71 KPHI 040419
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1219 AM EDT SAT AUG 4 2018

PAC077-095-040630-
/O.CON.KPHI.FF.W.0050.000000T0000Z-180804T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lehigh PA-Northampton PA-
1219 AM EDT SAT AUG 4 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 AM EDT FOR
LEHIGH AND NORTHAMPTON COUNTIES...

At 1217 AM EDT, Doppler radar indicated light to moderate rain 
across the warned area. Although the heavy rain has temporarily 
ended, runoff from previous heavy rainfall and anticipated heavier 
rainfall later tonight will likely lead to additional flash 
flooding. Flash flooding is likely imminent or occurring.

Some locations that could experience flooding include...
Allentown, Easton, Bethlehem, Forks, Emmaus, Northampton, Wilson,
Hellertown, Nazareth, Slatington, Wind Gap, Bath, Walnutport,
Belfast, West Easton, Tatamy, Steuben, Glendon, Neffs and Coffeetown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

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

&&

LAT...LON 4082 7548 4083 7538 4087 7528 4076 7518
      4074 7519 4073 7518 4068 7520 4068 7517
      4065 7520 4062 7519 4061 7520 4056 7530
      4042 7549 4064 7584

$$

CMS

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 3, 8:35 PM EDT	Areal Flood Advisory	PHI	Carbon	4 hr
Aug 3, 9:03 PM EDT	Flash Flood Warning	PHI	Berks	8 hr
Aug 3, 9:10 PM EDT	Areal Flood Advisory	PHI	Monroe, Northampton	4 hr
Aug 3, 10:07 PM EDT	Special Weather Statement	PHI	Lehigh, Northampton	53 min
Aug 3, 11:24 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh	6 hr
Aug 4, 12:24 AM EDT	Areal Flood Advisory	PHI	Carbon	4 hr
Aug 4, 1:08 AM EDT	Areal Flood Advisory	PHI	Monroe	4 hr
Aug 4, 1:15 AM EDT	Special Weather Statement	PHI	Berks	30 min
Aug 4, 1:47 AM EDT	Special Weather Statement	PHI	Berks, Lehigh	43 min
Aug 4, 1:59 AM EDT	Areal Flood Advisory	PHI	Chester	4 hr
Aug 4, 2:22 AM EDT	Areal Flood Warning	PHI	Lehigh, Northampton	21 hr
Aug 4, 2:27 AM EDT	Special Weather Statement	PHI	Lehigh, Northampton	63 min
Aug 4, 4:54 AM EDT	Areal Flood Warning	PHI	Berks	7 hr
Aug 4, 5:09 AM EDT	Areal Flood Advisory	PHI	Monroe	2 hr
Aug 4, 5:45 AM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Montgomery	7 hr
Aug 4, 6:45 AM EDT	River Flood Warning	PHI	Chester	4 hr
Aug 4, 6:55 AM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery	4 hr
Aug 4, 8:48 AM EDT	Areal Flood Warning	PHI	Chester, Montgomery	4 hr
Aug 4, 9:20 AM EDT	River Flood Warning	PHI	Montgomery	3 hr
Aug 4, 11:55 AM EDT	River Flood Warning	PHI	Chester, Montgomery, Philadelphia	12 hr
Aug 4, 4:41 PM EDT	Severe Thunderstorm Warning	PHI	Northampton	34 min

Nearby

Flash Flood Warnings in Pennsylvania, 2018 Every 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; radar from the NEXRAD Level II archive.