Alert archive / Pennsylvania / Special Weather Statements in 2012

Special Weather Statement, NWS Philadelphia/Mount Holly

August 9, 2012Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Aug 9, 2012, 3:05 PM EDT for Chester County, Montgomery County, Pennsylvania. It was in force for 85 min. 4 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 9, 2012, 3:05 PM EDT (19:05 UTC)
Expired: Aug 9, 2012, 4:30 PM EDT
In force: 85 min
Issued by: NWS Philadelphia/Mount Holly

Counties Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 102 km from the middle of the area, began a volume at 19:06 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 9, 3:15 PM EDT	TSTM WND GST 52	Pottstown, PA
Aug 9, 3:15 PM EDT	HAIL 0.88	Elverson, PA
Aug 9, 3:30 PM EDT	HAIL 0.75	Pottstown, PA
Aug 9, 3:36 PM EDT	TSTM WND DMG	South Coventry Twp, PA	TREES DOWN

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

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 7.1 hours before the alert went out and 85 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: 1906 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 754 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: 46 m²/s²
0-3 km storm-relative helicity: 37 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.

689 
WWUS81 KPHI 091905
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
305 PM EDT THU AUG 9 2012

PAZ067-068-092030-
CHESTER PA-MONTGOMERY PA-
305 PM EDT THU AUG 9 2012

...STRONG THUNDERSTORMS WILL AFFECT CHESTER AND MONTGOMERY
COUNTIES...

AT 302 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 13 MILES SOUTHEAST
OF READING TO 14 MILES WEST OF WEST CHESTER...MOVING EAST AT 15 MPH.
THE THUNDERSTORMS WILL BE NEAR GLENMOORE...SOUTH COATESVILLE AROUND
315 PM...THORNDALE AROUND 330 PM...KENILWORTH...CEDARVILLE AROUND 345
PM...SANATOGA...POTTSTOWN AROUND 400 PM...SPRING CITY AND ROYERSFORD
AROUND 415 PM.

VERY HEAVY RAIN WILL FALL FROM THESE STORMS...AND WILL CAUSE WATER TO
POND ON ROADS AND QUICKLY FILL POOR DRAINAGE AREAS.

WIND GUSTS TO 40 MPH AND SMALL HAIL ARE POSSIBLE WITH THESE STORMS.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THESE STORMS. DO
NOT SEEK SHELTER UNDER TREES WHEN LIGHTNING THREATENS...MOVE INDOORS
WHEN A THUNDERSTORM APPROACHES.

LAT...LON 4011 7594 4015 7585 4024 7570 4034 7562
      4039 7544 4038 7542 4004 7531 4004 7534
      4007 7536 4004 7541 4002 7541 3998 7559
      3993 7593

$$

FORECASTER: HEAVENER

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 1:17 PM EDT	Special Marine Warning	PHI		88 min
Aug 9, 1:46 PM EDT	Special Marine Warning	PHI		54 min
Aug 9, 2:01 PM EDT	Special Marine Warning	PHI		119 min
Aug 9, 2:20 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Warren	70 min
Aug 9, 2:25 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Somerset	65 min
Aug 9, 2:56 PM EDT	Special Weather Statement	PHI	Sussex	94 min
Aug 9, 3:23 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	71 min
Aug 9, 3:35 PM EDT	Special Weather Statement	PHI	Mercer, Middlesex, Morris, Somerset	55 min
Aug 9, 4:18 PM EDT	Special Weather Statement	PHI	Hunterdon	57 min
Aug 9, 4:33 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Somerset	57 min
Aug 9, 4:57 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Middlesex, Monmouth	78 min
Aug 9, 5:06 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Somerset	3 hr
Aug 9, 5:08 PM EDT	Special Weather Statement	PHI	Mercer, Middlesex, Monmouth	2 hr
Aug 9, 5:26 PM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer	2 hr
Aug 9, 5:48 PM EDT	Areal Flood Advisory	PHI	Middlesex	2 hr
Aug 9, 6:17 PM EDT	Flash Flood Warning	PHI	Middlesex	88 min
Aug 9, 1:00 PM EDT	Special Weather Statement	PHI	Lehigh	60 min
Aug 9, 1:22 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	68 min
Aug 9, 1:26 PM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery	3 hr
Aug 9, 1:33 PM EDT	Special Weather Statement	PHI	Northampton	57 min
Aug 9, 1:42 PM EDT	Special Weather Statement	PHI	Monroe	63 min
Aug 9, 1:45 PM EDT	Special Weather Statement	PHI	Berks	60 min
Aug 9, 2:13 PM EDT	Severe Thunderstorm Warning	PHI	Berks	77 min
Aug 9, 3:03 PM EDT	Special Weather Statement	PHI	Monroe	87 min
Aug 9, 3:11 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	6 hr
Aug 9, 3:20 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Montgomery	55 min
Aug 9, 3:39 PM EDT	Special Weather Statement	PHI	Bucks	66 min
Aug 9, 3:57 PM EDT	Areal Flood Advisory	PHI	Chester, Montgomery	104 min
Aug 9, 3:57 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	63 min
Aug 9, 7:01 PM EDT	Special Weather Statement	PHI	Berks	59 min
Aug 9, 7:10 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Carbon, Lehigh	80 min
Aug 9, 7:40 PM EDT	Special Weather Statement	PHI	Carbon, Monroe	95 min
Aug 9, 7:46 PM EDT	Areal Flood Advisory	PHI	Berks	3 hr
Aug 9, 12:34 PM EDT	Special Weather Statement	PHI	Kent	56 min
Aug 9, 1:04 PM EDT	Severe Thunderstorm Warning	PHI	Kent	23 min
Aug 9, 1:17 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	43 min
Aug 9, 1:39 PM EDT	Special Weather Statement	PHI	Kent	66 min
Aug 9, 1:55 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	65 min
Aug 9, 2:04 PM EDT	Special Weather Statement	PHI	Kent	56 min
Aug 9, 2:19 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	56 min
Aug 9, 2:23 PM EDT	Special Weather Statement	PHI	Sussex	52 min
Aug 9, 3:17 PM EDT	Special Weather Statement	PHI	Sussex	88 min
Aug 9, 3:42 PM EDT	Areal Flood Advisory	PHI	Sussex	119 min
Aug 9, 1:47 PM EDT	Special Weather Statement	PHI	Cecil	88 min

Nearby

Special Weather Statements in Pennsylvania, 2012 Every special weather statement in 2012

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.