Alert archive / Pennsylvania / Flash Flood Warnings in 2015

Flash Flood Warning 17, NWS Philadelphia/Mount Holly

June 26, 2015Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 26, 2015, 11:45 PM EDT for Chester County, Montgomery County, Pennsylvania. It was in force for 4 hr. 1 report 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: Jun 26, 2015, 11:45 PM EDT (03:45 UTC)
Expired: Jun 27, 2015, 3:45 AM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 100 km from the middle of the area, began a volume at 03:47 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.

What was reported inside it

Time	Report	Where	Remark
Jun 27, 2:00 AM EDT	HEAVY RAIN 3.5	Phoenixville, PA

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

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 3.8 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: 7 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 1208 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 1 m²/s²
0-3 km storm-relative helicity: 45 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

147 
WGUS51 KPHI 270345
FFWPHI
PAC029-091-270745-
/O.NEW.KPHI.FF.W.0017.150627T0345Z-150627T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1145 PM EDT FRI JUN 26 2015

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHEASTERN CHESTER COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  WEST CENTRAL MONTGOMERY COUNTY IN SOUTHEASTERN PENNSYLVANIA...

* UNTIL 345 AM EDT

* AT 1143 PM EDT...DOPPLER RADAR INDICATED VERY HEAVY RAIN ACROSS 
  THE WARNED AREA ASSOCIATED WITH SLOW MOVING HEAVY SHOWERS. RADAR 
  ESTIMATES INDICATED RAINFALL OF 2 TO 3 INCHES HAS FALLEN ALREADY 
  IN PORTIONS OF THE WARNED AREA AND ADDITIONAL RAIN IS EXPECTED. 
  THIS AMOUNT OF RAIN IN A SHORT PERIOD OF TIME WILL LEAD TO FLASH 
  FLOODING.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  POTTSTOWN...PHOENIXVILLE...ROYERSFORD...CHESTER SPRINGS...VALLEY
  FORGE...PUGHTOWN...KING OF PRUSSIA...SPRING CITY...KENILWORTH...
  SOUTH POTTSTOWN AND AUDUBON.

THIS INCLUDES THE FOLLOWING STREAMS AND DRAINAGES...CROSSMANS RUN...
PIGEON CREEK...BEAVER RUN...TROUT CREEK...PICKERING CREEK...
SCHUYLKILL RIVER...PERKIOMEN CREEK...VALLEY CREEK...FRENCH CREEK...
BIRCH RUN...MANATAWNY CREEK AND MINGO CREEK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING.

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

&&

LAT...LON 4020 7555 4011 7543 4009 7540 4007 7561
      4014 7569 4025 7566

$$

GORSE

1 follow-up statement

735 
WGUS71 KPHI 270709
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
309 AM EDT SAT JUN 27 2015

PAC029-091-270718-
/O.CAN.KPHI.FF.W.0017.000000T0000Z-150627T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CHESTER PA-MONTGOMERY PA-
309 AM EDT SAT JUN 27 2015

...THE FLASH FLOOD WARNING FOR NORTHEASTERN CHESTER AND WEST CENTRAL
MONTGOMERY COUNTIES IS CANCELLED...

ANY FLOOD WATERS ARE RECEDING AND THEREFORE THE FLASH FLOOD WARNING 
HAS BEEN CANCELLED.

LAT...LON 4020 7555 4011 7543 4009 7540 4007 7561
      4014 7569 4025 7566

$$

GORSE

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 26, 9:42 PM EDT	Areal Flood Advisory	PHI	Montgomery	4 hr
Jun 26, 10:38 PM EDT	Areal Flood Advisory	PHI	Montgomery, Philadelphia	3 hr
Jun 26, 10:59 PM EDT	Flash Flood Warning	PHI	Montgomery	4 hr
Jun 26, 11:13 PM EDT	Flash Flood Warning	PHI	Montgomery, Philadelphia	4 hr
Jun 27, 5:30 PM EDT	Coastal Flood Advisory	PHI	Delaware, Philadelphia	7 hr
Jun 27, 5:35 PM EDT	Areal Flood Advisory	PHI	Chester, Delaware, Montgomery, Philadelphia	4 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2015 Every flash flood warning in 2015

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.