Alert archive / Pennsylvania / Special Weather Statements in 2015

Special Weather Statement, NWS Philadelphia/Mount Holly

October 18, 2015Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Oct 18, 2015, 5:49 PM EDT for Montgomery County, Pennsylvania. It was in force for 56 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
Oct 18, 2015, 5:49 PM EDT (21:49 UTC)
Expired
Oct 18, 2015, 6:45 PM EDT
In force
56 min
Issued by
NWS Philadelphia/Mount Holly

County Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 93 km from the middle of the area, began a volume at 21:51 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 12:00Z, 9.8 hours before the alert went out and 210 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-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2015-10-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2015-10-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -26 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1326 m above ground
0-6 km bulk shear
70 kt
0-1 km storm-relative helicity
-26 m²/s²
0-3 km storm-relative helicity
34 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.

567 
WWUS81 KPHI 182149
SPSPHI

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
549 PM EDT SUN OCT 18 2015
 
PAZ101>104-182245-
WESTERN CHESTER-WESTERN MONTGOMERY-EASTERN MONTGOMERY-EASTERN
CHESTER-
549 PM EDT SUN OCT 18 2015

...A SHOWER WILL AFFECT NORTHEASTERN CHESTER AND CENTRAL 
MONTGOMERY COUNTIES...

AT 546 PM EDT...A SHOWER WAS OVER POTTSTOWN...OR 17 MILES SOUTHEAST
OF READING...MOVING SOUTHEAST AT 25 MPH.

WIND GUSTS UP TO 40 MPH AND GRAUPEL ARE LIKELY WITH THIS
SHOWER.  
 
LOCATIONS POSSIBLY IMPACTED INCLUDE...
NORRISTOWN...POTTSTOWN...PHOENIXVILLE...WEST NORRITON...EAST
NORRITON...CONSHOHOCKEN...AMBLER...COLLEGEVILLE...ROYERSFORD...
TRAPPE...SCHWENKSVILLE...PLYMOUTH MEETING...VALLEY FORGE...KING OF
PRUSSIA...CEDARVILLE...GILBERTSVILLE...PUGHTOWN...PAOLI...RADNOR
TOWNSHIP AND SKIPPACK.

LAT...LON 4025 7569 4033 7561 4014 7518 4004 7534
      4006 7536 4005 7540 4003 7540 4000 7545
      3998 7544 4020 7577
TIME...MOT...LOC 2148Z 307DEG 23KT 4023 7562 
$$

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 18, 4:30 PM EDTSpecial Marine WarningPHI2 hr
Oct 18, 5:58 PM EDTSpecial Marine WarningPHI2 hr
Oct 18, 6:14 PM EDTSpecial Weather StatementPHIAtlantic31 min
Oct 18, 6:17 PM EDTSpecial Weather StatementPHICape May58 min
Oct 18, 6:30 PM EDTSpecial Weather StatementPHICape May45 min
Oct 18, 3:22 AM EDTFrost AdvisoryPHIDelaware, Philadelphia11 hr
Oct 18, 5:38 PM EDTSpecial Weather StatementPHICaroline82 min
Oct 18, 4:36 PM EDTSpecial Weather StatementPHIKent69 min
Oct 18, 4:54 PM EDTSpecial Weather StatementPHIKent, Sussex66 min

Nearby

Special Weather Statements in Pennsylvania, 2015Every special weather statement 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.