Alert archive / Maryland / Tornado Warnings in 2012

Tornado Warning 40, NWS Baltimore/Washington

September 8, 2012Montgomery County, Prince George's County, Maryland

NWS Baltimore/Washington issued this tornado warning at Sep 8, 2012, 3:53 PM EDT for Montgomery County, Prince George's County, Maryland. It was in force for 15 min. 2 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
Sep 8, 2012, 3:53 PM EDT (19:53 UTC)
Expired
Sep 8, 2012, 4:08 PM EDT
In force
15 min
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon

Counties Montgomery County, MD, Prince George's County, MD

The radar

The Sterling radar (KLWX), 52 km from the middle of the area, began a volume at 19:56 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

TimeReportWhereRemark
Sep 8, 4:05 PM EDTTSTM WND GST 592 Ene Beltsville, MD
Sep 8, 4:09 PM EDTTSTM WND GST 582 W Glenn Dale, MD

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Sep 8, 12:15 PM EDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.9 hours before the alert went out and 45 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 2012-09-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 252 joules per kilogram.LCLLFCEL10008507005003002001001 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 2012-09-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 150 square meters per square second.193958Sfc1 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
252 J/kg
Mixed-layer CIN
-81 J/kg
Mixed-layer LCL
638 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
150 m²/s²
0-3 km storm-relative helicity
140 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.0

Open this sounding in Storm Lab

The text

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

141 
WFUS51 KLWX 081953
TORLWX
MDC031-033-082030-
/O.NEW.KLWX.TO.W.0040.120908T1953Z-120908T2030Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
353 PM EDT SAT SEP 8 2012

THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHEASTERN MONTGOMERY COUNTY IN CENTRAL MARYLAND...
  NORTHERN PRINCE GEORGES COUNTY IN CENTRAL MARYLAND...

* UNTIL 430 PM EDT

* AT 352 PM EDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A
  TORNADO WAS NEAR WHITE OAK...OR NEAR LANGLEY PARK...AND WAS MOVING
  EAST AT 30 MPH.

* LOCATIONS IMPACTED INCLUDE...
  BELTSVILLE...
  COLLEGE PARK...
  GREENBELT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING AND AVOID WINDOWS. IF OUTDOORS OR IN A MOBILE HOME OR
VEHICLE...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

MOTORISTS SHOULD NOT TAKE SHELTER UNDER HIGHWAY OVERPASSES. AS A LAST
RESORT...EITHER PARK AND STAY IN YOUR VEHICLE...OR ABANDON YOUR
VEHICLE AND LAY FLAT IN A LOW SPOT.

THIS TORNADO MAY BE WRAPPED IN RAIN AND HARD TO SEE. TAKE COVER NOW.

&&

LAT...LON 3906 7681 3896 7684 3902 7702 3907 7700
TIME...MOT...LOC 1953Z 291DEG 26KT 3903 7697

$$

GMS
2 follow-up statements
323 
WWUS51 KLWX 082001
SVSLWX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
401 PM EDT SAT SEP 8 2012

MDC031-082011-
/O.CAN.KLWX.TO.W.0040.000000T0000Z-120908T2030Z/
MONTGOMERY MD-
401 PM EDT SAT SEP 8 2012

...THE TORNADO WARNING IS CANCELLED FOR MONTGOMERY COUNTY...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS EXITED THE WARNED
AREA. THUS THE TORNADO WARNING HAS BEEN CANCELLED.

LAT...LON 3907 7693 3906 7681 3896 7684 3900 7695
TIME...MOT...LOC 2001Z 291DEG 26KT 3902 7688

$$

MDC033-082030-
/O.CON.KLWX.TO.W.0040.000000T0000Z-120908T2030Z/
PRINCE GEORGES MD-
401 PM EDT SAT SEP 8 2012

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 430 PM EDT FOR PRINCE
GEORGES COUNTY...

AT 359 PM EDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO
WAS LOCATED NEAR BELTSVILLE...AND WAS MOVING EAST AT 30 MPH.

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING AND AVOID WINDOWS. IF OUTDOORS OR IN A MOBILE HOME OR
VEHICLE...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

MOTORISTS SHOULD NOT TAKE SHELTER UNDER HIGHWAY OVERPASSES. AS A LAST
RESORT...EITHER PARK AND STAY IN YOUR VEHICLE...OR ABANDON YOUR
VEHICLE AND LAY FLAT IN A LOW SPOT.

THIS TORNADO MAY BE WRAPPED IN RAIN AND HARD TO SEE. DO NOT WAIT TO
SEE OR HEAR THE TORNADO. TAKE COVER NOW.

&&

LAT...LON 3907 7693 3906 7681 3896 7684 3900 7695
TIME...MOT...LOC 2001Z 291DEG 26KT 3902 7688

$$

GMS
398 
WWUS51 KLWX 082008
SVSLWX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
408 PM EDT SAT SEP 8 2012

MDC033-082019-
/O.CAN.KLWX.TO.W.0040.000000T0000Z-120908T2030Z/
PRINCE GEORGES MD-
408 PM EDT SAT SEP 8 2012

...THE TORNADO WARNING IS CANCELLED FOR PRINCE GEORGES COUNTY...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS EXITED THE WARNED
AREA. THUS THE TORNADO WARNING HAS BEEN CANCELLED.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT FOR THE WARNED AREA.

LAT...LON 3907 7693 3906 7681 3896 7684 3900 7695
TIME...MOT...LOC 2009Z 291DEG 26KT 3900 7681

$$

GMS

The office that day

Everything else NWS Baltimore/Washington issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 8, 12:02 PM EDTSevere Thunderstorm WarningLWXWashington43 min
Sep 8, 12:22 PM EDTSpecial Weather StatementLWXWashington23 min
Sep 8, 12:35 PM EDTSevere Thunderstorm WarningLWXFrederick, Washington40 min
Sep 8, 12:47 PM EDTTornado WarningLWXWashington16 min
Sep 8, 1:09 PM EDTSevere Thunderstorm WarningLWXCarroll, Frederick, Washington66 min
Sep 8, 2:02 PM EDTSpecial Weather StatementLWXBaltimore58 min
Sep 8, 2:10 PM EDTSevere Thunderstorm WarningLWXBaltimore, Carroll, Frederick, Harford, Howard, Montgomery80 min
Sep 8, 2:47 PM EDTSevere Thunderstorm WarningLWXMontgomery58 min
Sep 8, 3:18 PM EDTSpecial Weather StatementLWXAnne Arundel, Montgomery, Prince George's87 min
Sep 8, 3:22 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Charles, Howard, Montgomery, Prince George's68 min
Sep 8, 3:27 PM EDTSpecial Weather StatementLWXHarford33 min
Sep 8, 3:58 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Baltimore, Calvert, Charles, Howard, Montgomery and 3 more55 min
Sep 8, 4:06 PM EDTTornado WarningLWXAnne Arundel, Prince George's39 min
Sep 8, 4:25 PM EDTSpecial Weather StatementLWXKent20 min

Nearby

Tornado Warnings in Maryland, 2012Every tornado warning in 2012Tornadoes 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.