Alert archive / Pennsylvania / Areal Flood Warnings in 2010

Areal Flood Warning 32, NWS Philadelphia/Mount Holly

September 30, 201010 counties in Pennsylvania; 5 counties in Maryland

NWS Philadelphia/Mount Holly issued this areal flood warning at Sep 30, 2010, 1:48 PM EDT for 10 counties in Pennsylvania; 5 counties in Maryland. It was in force for 6 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 30, 2010, 1:48 PM EDT (17:48 UTC)
Expired
Sep 30, 2010, 7:45 PM EDT
In force
6 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Caroline County, MD, Cecil County, MD, Kent County, MD, Queen Anne's County, MD, Talbot County, MD, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 106 km from the middle of the area, began a volume at 17:51 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, 5.8 hours before the alert went out and 189 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 2010-09-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 47 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2010-09-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 514 square meters per square second.19395878Sfc1 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
47 J/kg
Mixed-layer CIN
-41 J/kg
Mixed-layer LCL
449 m above ground
0-6 km bulk shear
77 kt
0-1 km storm-relative helicity
514 m²/s²
0-3 km storm-relative helicity
665 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.3

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Philadelphia/Mount Holly wrote its last area forecast discussion before this areal flood warning went out at Sep 30, 1:28 PM EDT, 20 minutes earlier.

Area forecast discussion, Sep 30, 1:28 PM EDT, 20 minutes before
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Hazardous weather outlook, Sep 30, 12:53 PM EDT, 55 minutes before
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In the hours before

Special weather statement, Sep 30, 11:21 AM EDT, 2 hours 27 minutes before
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Special weather statement, Sep 30, 12:15 PM EDT, 1 hour 33 minutes before
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Special weather statement, Sep 30, 1:37 PM EDT, 11 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
137 PM EDT THU SEP 30 2010

MDZ012-015-019-020-301815-
CAROLINE MD-KENT MD-QUEEN ANNE'S MD-TALBOT MD-
137 PM EDT THU SEP 30 2010

...A SERIES OF HEAVY SHOWERS WITH STRONG WIND GUSTS WILL AFFECT
CAROLINE...KENT...QUEEN ANNE'S AND TALBOT COUNTIES...

AT 134 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SERIES OF SHOWERS WITH STRONG WIND GUSTS 20 MILES SOUTH OF
EASTON...MOVING NORTH AT 50 MPH. THE SHOWER WILL BE NEAR
TRAPPE...WINDYHILL...CHOPTANK AROUND 150
PM...HAMBLETON...OXFORD...TANYARD AROUND 155 PM...EASTON...ST.
MICHAELS AROUND 200 PM...COPPERVILLE AND MATTHEWS AROUND 205 PM.

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

WIND GUSTS TO 50 MPH ARE POSSIBLE WITH THESE SHOWERS.

LAT...LON 3873 7627 3884 7630 3887 7625 3882 7620
      3893 7621 3894 7624 3890 7624 3893 7628
      3890 7629 3891 7632 3902 7634 3904 7629
      3898 7621 3899 7620 3903 7625 3907 7590
      3867 7594 3856 7605

FORECASTER: HEAVENER

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 30, 7:33 AM EDTSpecial Weather StatementPHIWarren117 min
Sep 30, 1:51 PM EDTCoastal Flood WarningPHICumberland, Salem5 hr
Sep 30, 2:19 PM EDTAreal Flood WarningPHICamden, Cumberland, Gloucester, Salem6 hr
Sep 30, 6:18 PM EDTSpecial Weather StatementPHISalem117 min
Sep 30, 6:50 PM EDTSpecial Weather StatementPHIGloucester, Salem40 min
Sep 30, 7:37 PM EDTSpecial Weather StatementPHIGloucester113 min
Sep 30, 7:50 PM EDTAreal Flood WarningPHICamden, Cumberland, Gloucester, Hunterdon, Salem, Sussex and 1 more16 hr
Sep 30, 6:06 AM EDTAreal Flood WarningPHIBerks, Chester4 hr
Sep 30, 8:03 AM EDTAreal Flood WarningPHIBerks, Carbon, Chester, Lehigh, Montgomery4 hr
Sep 30, 9:31 AM EDTAreal Flood WarningPHILehigh, Monroe, Northampton3 hr
Sep 30, 2:12 PM EDTAreal Flood WarningPHIBerks6 hr
Sep 30, 6:55 PM EDTRiver Flood WarningPHIChester, Delaware30 hr
Sep 30, 6:57 PM EDTRiver Flood WarningPHIBerks, Montgomery16 hr
Sep 30, 8:00 AM EDTTornado WarningPHIKent45 min
Sep 30, 11:21 AM EDTSpecial Weather StatementPHIKent, Talbot39 min
Sep 30, 12:15 PM EDTSpecial Weather StatementPHIQueen Anne's45 min
Sep 30, 1:37 PM EDTSpecial Weather StatementPHIQueen Anne's, Talbot38 min
Sep 30, 3:15 PM EDTSpecial Weather StatementPHICaroline45 min
Sep 30, 3:47 PM EDTSpecial Weather StatementPHICaroline58 min
Sep 30, 6:23 PM EDTSpecial Weather StatementPHICaroline37 min
Sep 30, 7:49 PM EDTCoastal Flood WarningPHICaroline, Kent, Queen Anne's, Talbot6 hr

Nearby

Areal Flood Warnings in Pennsylvania, 2010Areal Flood Warnings in Maryland, 2010Every areal flood warning in 2010

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.