Alert archive / Pennsylvania / Special Weather Statements in 2011

Special Weather Statement, NWS Philadelphia/Mount Holly

August 7, 2011Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Aug 7, 2011, 12:48 AM EDT for Montgomery County, Pennsylvania. It was in force for 57 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 7, 2011, 12:48 AM EDT (04:48 UTC)
Expired: Aug 7, 2011, 1:45 AM EDT
In force: 57 min
Issued by: NWS Philadelphia/Mount Holly

County Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 121 km from the middle of the area, began a volume at 04:50 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.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 4.8 hours before the alert went out and 203 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: 1834 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 508 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 109 m²/s²
0-3 km storm-relative helicity: 182 m²/s²
Significant tornado parameter: 1.1
Supercell composite: 6.8

Open this sounding in Storm Lab

The text

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

023 
WWUS81 KPHI 070448
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1248 AM EDT SUN AUG 7 2011

PAZ060-061-067>069-070545-
BERKS PA-BUCKS PA-CHESTER PA-LEHIGH PA-MONTGOMERY PA-
1248 AM EDT SUN AUG 7 2011

...A STRONG THUNDERSTORM WILL AFFECT BERKS...BUCKS...CHESTER...LEHIGH
AND MONTGOMERY COUNTIES...

AT 1246 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 7 MILES SOUTH OF READING...MOVING EAST AT 20 MPH.
THE THUNDERSTORM WILL BE NEAR FLYING HILLS...LORANE AROUND 100 AM...
BIRDSBORO...AMITY GARDENS AROUND 115 AM...HALFWAY HOUSE...STOWE
AROUND 130 AM...GILBERTSVILLE AND BOYERTOWN AROUND 145 AM.

VERY HEAVY RAIN WILL FALL FROM THIS STORM...AND WILL CAUSE WATER TO
POND ON ROADS AND QUICKLY FILL ROADSIDE DITCHES AND SMALL STREAMS.

WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THIS STORM.

LAT...LON 4057 7545 4020 7533 4007 7595 4011 7595
      4014 7590 4025 7606 4028 7610

$$

HAYES

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 6, 8:49 PM EDT	Flood Watch	PHI	Morris, Sussex, Warren	9 hr
Aug 6, 10:33 PM EDT	Areal Flood Advisory	PHI	Warren	6 hr
Aug 7, 12:42 AM EDT	Special Weather Statement	PHI	Morris	63 min
Aug 7, 1:32 AM EDT	Areal Flood Advisory	PHI	Hunterdon, Warren	3 hr
Aug 7, 1:54 AM EDT	Areal Flood Advisory	PHI	Hunterdon, Morris, Sussex, Warren	3 hr
Aug 7, 3:56 AM EDT	Special Weather Statement	PHI	Hunterdon	64 min
Aug 7, 4:45 AM EDT	Special Weather Statement	PHI	Hunterdon, Somerset	60 min
Aug 7, 5:10 AM EDT	Areal Flood Advisory	PHI	Morris, Somerset	81 min
Aug 7, 5:30 AM EDT	Special Weather Statement	PHI	Mercer, Middlesex	60 min
Aug 7, 6:03 AM EDT	Flash Flood Watch	PHI	Sussex, Warren	14 hr
Aug 7, 3:25 PM EDT	Special Weather Statement	PHI	Mercer	35 min
Aug 7, 3:34 PM EDT	Special Weather Statement	PHI	Warren	26 min
Aug 7, 3:48 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Monmouth, Ocean	27 min
Aug 7, 4:19 PM EDT	Special Weather Statement	PHI	Monmouth	41 min
Aug 7, 5:02 PM EDT	Special Weather Statement	PHI	Sussex	28 min
Aug 7, 6:49 PM EDT	Special Weather Statement	PHI	Sussex	41 min
Aug 7, 7:11 PM EDT	Special Weather Statement	PHI	Sussex	49 min
Aug 7, 7:35 PM EDT	Special Weather Statement	PHI	Sussex	25 min
Aug 6, 10:06 PM EDT	Special Weather Statement	PHI	Berks	84 min
Aug 6, 10:14 PM EDT	Special Weather Statement	PHI	Pike	61 min
Aug 7, 2:29 AM EDT	Flash Flood Warning	PHI	Berks, Lehigh, Northampton	3 hr
Aug 7, 3:07 PM EDT	Special Weather Statement	PHI	Philadelphia	23 min
Aug 7, 7:20 PM EDT	Special Weather Statement	PHI	Monroe	40 min
Aug 7, 3:02 PM EDT	Special Weather Statement	PHI	Cecil	28 min
Aug 7, 4:50 PM EDT	Special Weather Statement	PHI	Cecil	40 min
Aug 7, 5:39 PM EDT	Special Weather Statement	PHI	Cecil	36 min
Aug 7, 6:31 PM EDT	Special Weather Statement	PHI	Kent	29 min

Nearby

Special Weather Statements in Pennsylvania, 2011 Every special weather statement in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.