Alert archive / Pennsylvania / Flash Flood Warnings in 2014

Flash Flood Warning 42, NWS Philadelphia/Mount Holly

July 27, 2014Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 27, 2014, 10:33 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: Jul 27, 2014, 10:33 PM EDT (02:33 UTC)
Expired: Jul 28, 2014, 2:30 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), 93 km from the middle of the area, began a volume at 02:36 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
Jul 27, 11:09 PM EDT	FLASH FLOOD	Lower Providence Twp, PA	ROBODA BLVD AND SPRINGER TOWN RD CLOSED.

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, 2.6 hours before the alert went out and 212 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: 1013 J/kg
Mixed-layer CIN: -35 J/kg
Mixed-layer LCL: 1007 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 67 m²/s²
0-3 km storm-relative helicity: 103 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 2.7

Open this sounding in Storm Lab

The text

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

641 
WGUS51 KPHI 280233
FFWPHI
PAC029-091-280630-
/O.NEW.KPHI.FF.W.0042.140728T0233Z-140728T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1033 PM EDT SUN JUL 27 2014

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  EAST CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 230 AM EDT

* AT 1030 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  THAT VERY HEAVY RAIN WAS CONTINUING TO MOVE INTO THE AREA FROM
  THE SOUTHWEST. THE HEAVY RAIN WILL CONTINUE UNTIL AFTER MIDNIGHT
  IN PARTS OF THE AREA. SOME LOCATIONS COULD RECEIVE UP TO THREE
  OR FOUR INCHES OF RAINFALL.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  GILBERTSVILLE...EAST GREENVILLE...SOUDERTON...SCHWENKSVILLE...
  HATFIELD AND GREEN LANE

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE 
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS 
SAFELY. BE PREPARED TO MOVE TO HIGHER GROUND IF YOU LIVE IN A FLOOD 
PRONE LOCATION.

&&

LAT...LON 4045 7553 4023 7517 4006 7535 4006 7537
      4004 7541 4002 7541 3999 7545 3998 7544
      3995 7552 3990 7556 4030 7553 4030 7564
      4031 7564

$$

IOVINO

2 follow-up statements

941 
WGUS71 KPHI 280343
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1143 PM EDT SUN JUL 27 2014

PAC029-091-280630-
/O.CON.KPHI.FF.W.0042.000000T0000Z-140728T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MONTGOMERY PA-CHESTER PA-
1143 PM EDT SUN JUL 27 2014

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 AM EDT FOR EAST
CENTRAL CHESTER AND MONTGOMERY COUNTIES...

AT 1140 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THAT THE HEAVY RAIN HAD MOVED OUT OF THE AREA. HOWEVER...RUNOFF FROM 
THE EARLIER HEAVY RAINFALL WILL CONTINUE TO CAUSE SOME FLOODING AND 
THE WARNING REMAINS IN EFFECT.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
PHOENIXVILLE...GILBERTSVILLE...EAST GREENVILLE...TRAPPE...
SOUDERTON...SCHWENKSVILLE...ROYERSFORD...LANSDALE...HATFIELD...GREEN
LANE AND COLLEGEVILLE

LAT...LON 4045 7553 4023 7517 4006 7535 4006 7537
      4004 7541 4002 7541 3999 7545 3998 7544
      3995 7552 3990 7556 4030 7553 4030 7564
      4031 7564

$$

IOVINO

069 
WGUS71 KPHI 280546
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
146 AM EDT MON JUL 28 2014

PAC029-091-280555-
/O.CAN.KPHI.FF.W.0042.000000T0000Z-140728T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MONTGOMERY PA-CHESTER PA-
146 AM EDT MON JUL 28 2014

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR EAST CENTRAL
CHESTER AND MONTGOMERY COUNTIES...

THE HEAVY RAIN HAS MOVED OUT OF THE AREA AND WATER LEVELS CONTINUE 
TO SUBSIDE. AS A RESULT, THE FLASH FLOOD WARNING HAS BEEN CANCELLED.

LAT...LON 4045 7553 4023 7517 4006 7535 4006 7537
      4004 7541 4002 7541 3999 7545 3998 7544
      3995 7552 3990 7556 4030 7553 4030 7564
      4031 7564

$$

IOVINO

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 27, 8:28 PM EDT	Special Weather Statement	PHI	Berks	62 min
Jul 27, 8:42 PM EDT	Areal Flood Advisory	PHI	Chester, Montgomery	3 hr
Jul 27, 9:12 PM EDT	Special Weather Statement	PHI	Chester	63 min
Jul 27, 9:21 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester	54 min
Jul 27, 9:43 PM EDT	Flash Flood Warning	PHI	Berks, Chester, Montgomery	4 hr
Jul 27, 10:20 PM EDT	Special Weather Statement	PHI	Chester, Montgomery	55 min
Jul 27, 10:26 PM EDT	Areal Flood Advisory	PHI	Bucks, Lehigh, Northampton	3 hr
Jul 27, 10:44 PM EDT	Special Weather Statement	PHI	Chester, Delaware	61 min
Jul 27, 10:47 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	43 min
Jul 27, 11:28 PM EDT	Special Weather Statement	PHI	Delaware, Philadelphia	62 min
Jul 27, 11:32 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	58 min
Jul 28, 12:31 AM EDT	Flash Flood Warning	PHI	Delaware, Montgomery, Philadelphia	3 hr
Jul 28, 12:35 AM EDT	Special Weather Statement	PHI	Bucks, Chester, Delaware, Philadelphia	85 min
Jul 28, 2:58 AM EDT	River Flood Warning	PHI	Chester	8 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2014 Every flash flood warning in 2014

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.