Alert archive / Maryland / Flash Flood Warnings in 2019

Flash Flood Warning 35, NWS Baltimore/Washington

October 31, 2019Montgomery County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Oct 31, 2019, 9:37 PM EDT for Montgomery County, Maryland. It was in force for 3 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
Oct 31, 2019, 9:37 PM EDT (01:37 UTC)
Expired
Nov 1, 2019, 12:30 AM EDT
In force
3 hr
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Flood severity
None

County Montgomery County, MD

The radar

The Sterling radar (KLWX), 30 km from the middle of the area, began a volume at 01:39 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, 1.6 hours before the alert went out and 27 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 00:00Z on 2019-11-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 529 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 00:00Z on 2019-11-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 623 square meters per square second.1939587897Sfc1 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
529 J/kg
Mixed-layer CIN
-20 J/kg
Mixed-layer LCL
827 m above ground
0-6 km bulk shear
72 kt
0-1 km storm-relative helicity
623 m²/s²
0-3 km storm-relative helicity
752 m²/s²
Significant tornado parameter
2.5
Supercell composite
9.8

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 31, 8:27 PM EDTSevere Thunderstorm WarningLWXCulpeper, Fauquier, Madison, Orange, Stafford33 min
Oct 31, 9:08 PM EDTSevere Thunderstorm WarningLWXFairfax, City of Fairfax37 min
Oct 31, 9:24 PM EDTSevere Thunderstorm WarningLWXPrince William, Stafford, City of Fredericksburg36 min
Oct 31, 9:26 PM EDTSpecial Marine WarningLWX32 min
Oct 31, 9:52 PM EDTAreal Flood WarningLWXAlbemarle, Greene, Madison100 min
Oct 31, 10:07 PM EDTSevere Thunderstorm WarningLWXArlington, Fairfax, Prince William, City of Alexandria, City of Fairfax, City of Falls Church38 min
Oct 31, 10:09 PM EDTSpecial Marine WarningLWX37 min
Oct 31, 10:44 PM EDTSpecial Marine WarningLWX46 min
Oct 31, 11:09 PM EDTSpecial Marine WarningLWX55 min
Oct 31, 11:15 PM EDTSpecial Marine WarningLWX30 min
Oct 31, 11:18 PM EDTSpecial Marine WarningLWX46 min
Nov 1, 12:07 AM EDTSpecial Marine WarningLWX83 min
Nov 1, 1:00 AM EDTAreal Flood WarningLWXArlington, Fairfax, City of Alexandria, City of Fairfax, City of Falls Church4 hr
Nov 1, 2:23 AM EDTAreal Flood WarningLWXCulpeper, Madison, Orange3 hr
Nov 1, 4:07 AM EDTFreeze WatchLWXArlington, Fairfax, King George, Loudoun, Nelson, Spotsylvania and 6 more5 hr
Nov 1, 6:58 AM EDTAreal Flood WarningLWXFairfax, Prince William, City of Manassas Park2 hr
Nov 1, 9:17 AM EDTFreeze WarningLWXArlington, Fairfax, King George, Loudoun, Nelson, Spotsylvania and 6 more24 hr
Nov 1, 2:13 PM EDTSmall Craft AdvisoryLWX4 hr
Oct 31, 8:32 PM EDTSevere Thunderstorm WarningLWXCarroll, Howard, Montgomery28 min
Oct 31, 9:00 PM EDTAreal Flood WarningLWXFrederick, Howard, Montgomery3 hr
Oct 31, 9:20 PM EDTSevere Thunderstorm WarningLWXHoward, Montgomery25 min
Oct 31, 9:51 PM EDTAreal Flood WarningLWXBaltimore, Carroll, Howard, Montgomery3 hr
Oct 31, 10:14 PM EDTSevere Thunderstorm WarningLWXBaltimore, Harford46 min
Oct 31, 10:22 PM EDTAreal Flood WarningLWXBaltimore, Howard, City of Baltimore2 hr
Oct 31, 10:35 PM EDTRiver Flood WarningLWXMontgomery14 hr
Oct 31, 10:40 PM EDTFlash Flood WarningLWXBaltimore, City of Baltimore101 min
Oct 31, 10:41 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Baltimore, Prince George's49 min
Oct 31, 10:51 PM EDTAreal Flood WarningLWXHoward91 min
Oct 31, 10:56 PM EDTSevere Thunderstorm WarningLWXCharles34 min
Oct 31, 11:10 PM EDTSevere Thunderstorm WarningLWXCalvert, Charles, Saint Mary's50 min
Oct 31, 11:22 PM EDTSevere Thunderstorm WarningLWXSaint Mary's38 min
Oct 31, 11:23 PM EDTSevere Thunderstorm WarningLWXCalvert22 min
Nov 1, 12:55 AM EDTAreal Flood WarningLWXBaltimore9 hr
Nov 1, 12:57 AM EDTAreal Flood WarningLWXAnne Arundel, Baltimore, Howard, City of Baltimore12 hr
Nov 1, 1:42 AM EDTAreal Flood WarningLWXAnne Arundel, Howard8 hr
Nov 1, 2:48 AM EDTAreal Flood WarningLWXHoward, Montgomery3 hr
Nov 1, 4:07 AM EDTWind AdvisoryLWXAllegany5 hr
Nov 1, 5:46 AM EDTAreal Flood WarningLWXCarroll, Frederick5 hr

Nearby

Flash Flood Warnings in Maryland, 2019Every flash flood warning in 2019

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.