Alert archive / Maryland / Flash Flood Warnings in 2019

Flash Flood Warning 29, NWS Baltimore/Washington

July 31, 2019Allegany County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Jul 31, 2019, 1:36 PM EDT for Allegany 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
Jul 31, 2019, 1:36 PM EDT (17:36 UTC)
Expired
Jul 31, 2019, 4:12 PM EDT
In force
3 hr
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Flood severity
None

County Allegany County, MD

The radar

The Sterling radar (KLWX), 127 km from the middle of the area, began a volume at 17:39 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 12:00Z, 5.6 hours before the alert went out and 134 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 2019-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 224 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 2019-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -56 square meters per square second.1939Sfc1 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
224 J/kg
Mixed-layer CIN
-161 J/kg
Mixed-layer LCL
1257 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
-56 m²/s²
0-3 km storm-relative helicity
8 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Baltimore/Washington wrote its last area forecast discussion before this flash flood warning went out at Jul 31, 10:24 AM EDT, 3 hours 12 minutes earlier.

Area forecast discussion, Jul 31, 10:24 AM EDT, 3 hours 12 minutes before
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Hazardous weather outlook, Jul 31, 1:30 PM EDT, 6 minutes before
Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
130 PM EDT Wed Jul 31 2019

ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-011000-
Chesapeake Bay north of Pooles Island MD-
Chesapeake Bay from Pooles Island to Sandy Point MD-
Chesapeake Bay from Sandy Point to North Beach MD-
Chesapeake Bay from North Beach to Drum Point MD-
Chesapeake Bay from Drum Point MD to Smith Point VA-
Tidal Potomac from Key Bridge to Indian Head MD-
Tidal Potomac from Indian Head to Cobb Island MD-
Tidal Potomac from Cobb Island MD to Smith Point VA-
Patapsco River including Baltimore Harbor-
Chester River to Queenstown MD-Eastern Bay-
Choptank River to Cambridge MD and the Little Choptank River-
Patuxent River to Broomes Island MD-
Tangier Sound and the inland waters surrounding Bloodsworth
Island-District of Columbia-Southern Baltimore-Prince Georges-
Anne Arundel-Charles-St. Marys-Calvert-Southeast Harford-
Prince William/Manassas/Manassas Park-Fairfax-
Arlington/Falls Church/Alexandria-Stafford-Spotsylvania-
King George-
130 PM EDT Wed Jul 31 2019

This Hazardous Weather Outlook is for the Maryland portion of the
Chesapeake Bay, Tidal Potomac River, and adjacent counties in
central Maryland and northern Virginia as well as the District of
Columbia.

.DAY ONE...This Afternoon and Tonight

Severe Thunderstorm Watch 547 is in effect until 9 PM for the
outlook area. Thunderstorms may produce scattered incidents of
damaging wind gusts this afternoon and evening. Heavy rain may
also lead to isolated instances of flooding and the highest risk
is along the I-95 corridor where a Flash Flood Watch is in effect.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Thunderstorms may produce heavy rainfall which may result in
isolated instances of flooding Thursday and Friday. The highest
risk is south of the US 50 corridor.

.SPOTTER INFORMATION STATEMENT...

The spotter network has been activated.

MDZ003>006-501>507-VAZ025>031-036>040-050-051-501>508-WVZ050>053-
055-501>506-011000-
Washington-Frederick MD-Carroll-Northern Baltimore-
Extreme Western Allegany-Central and Eastern Allegany-
Northwest Montgomery-Central and Southeast Montgomery-
Northwest Howard-Central and Southeast Howard-Northwest Harford-
Augusta-Rockingham-Shenandoah-Frederick VA-Page-Warren-Clarke-
Nelson-Albemarle-Greene-Madison-Rappahannock-Orange-Culpeper-
Northern Fauquier-Southern Fauquier-Western Highland-
Eastern Highland-Western Loudoun-Eastern Loudoun-
Northern Virginia Blue Ridge-Central Virginia Blue Ridge-
Hampshire-Morgan-Berkeley-Jefferson-Hardy-Western Grant-
Eastern Grant-Western Mineral-Eastern Mineral-Western Pendleton-
Eastern Pendleton-
130 PM EDT Wed Jul 31 2019

This Hazardous Weather Outlook is for eastern West Virginia,
northern and central Virginia, and central and western Maryland
with the exception of Garrett County.

.DAY ONE...This Afternoon and Tonight

Severe Thunderstorm Watch 547 is in effect until 9 PM for portions
of central and northern Maryland and northern and central Virginia.
Thunderstorms may produce scattered incidents of damaging wind
gusts this afternoon and evening. Heavy rain may also lead to
isolated instances of flooding and the highest risk is along the
I-95 corridor where a Flash Flood Watch is in effect.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Thunderstorms may produce heavy rainfall which may result in
isolated instances of flooding Thursday and Friday. The highest
risk is south of the US 50 corridor.

.SPOTTER INFORMATION STATEMENT...

The spotter network has been activated.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 9:25 PM EDTAreal Flood WarningLWXAlbemarle86 min
Jul 31, 12:02 PM EDTFlash Flood WatchLWXArlington, Fairfax, City of Alexandria, City of Fairfax, City of Falls Church7 hr
Jul 31, 2:36 PM EDTSpecial Marine WarningLWX84 min
Jul 31, 2:48 PM EDTSevere Thunderstorm WarningLWXRockingham, City of Harrisonburg42 min
Jul 31, 2:56 PM EDTFlash Flood WarningLWXAugusta3 hr
Jul 31, 3:03 PM EDTSevere Thunderstorm WarningLWXAugusta15 min
Jul 31, 3:04 PM EDTSevere Thunderstorm WarningLWXAugusta41 min
Jul 31, 3:22 PM EDTSevere Thunderstorm WarningLWXAlbemarle, Augusta, Greene, Rockingham38 min
Jul 31, 3:25 PM EDTSevere Thunderstorm WarningLWXGreene, Madison, Page, Rockingham50 min
Jul 31, 3:28 PM EDTFlash Flood WarningLWXGreene, Madison2 hr
Jul 31, 3:31 PM EDTSevere Thunderstorm WarningLWXPage, Rockingham44 min
Jul 31, 3:33 PM EDTSpecial Marine WarningLWX87 min
Jul 31, 3:39 PM EDTSevere Thunderstorm WarningLWXAugusta, Nelson40 min
Jul 31, 3:50 PM EDTSevere Thunderstorm WarningLWXAlbemarle, Augusta, Nelson, City of Charlottesville, City of Waynesboro40 min
Jul 31, 3:57 PM EDTAreal Flood WarningLWXAlbemarle, Augusta, Greene, Nelson, Page, Rockingham and 1 more2 hr
Jul 31, 4:01 PM EDTSpecial Marine WarningLWX33 min
Jul 31, 4:03 PM EDTSpecial Marine WarningLWX87 min
Jul 31, 4:04 PM EDTSevere Thunderstorm WarningLWXCulpeper, Madison, Orange41 min
Jul 31, 4:13 PM EDTSevere Thunderstorm WarningLWXAlbemarle, Greene, Madison, Orange47 min
Jul 31, 4:18 PM EDTSevere Thunderstorm WarningLWXAlbemarle, City of Charlottesville57 min
Jul 31, 4:37 PM EDTSpecial Marine WarningLWX83 min
Jul 31, 4:42 PM EDTSevere Thunderstorm WarningLWXCulpeper, Madison, Orange, Spotsylvania63 min
Jul 31, 4:53 PM EDTSpecial Marine WarningLWX97 min
Jul 31, 4:55 PM EDTSpecial Marine WarningLWX95 min
Jul 31, 5:05 PM EDTSevere Thunderstorm WarningLWXOrange, Spotsylvania29 min
Jul 31, 5:25 PM EDTSpecial Marine WarningLWX95 min
Jul 31, 5:29 PM EDTSpecial Marine WarningLWX67 min
Jul 31, 5:36 PM EDTSevere Thunderstorm WarningLWXSpotsylvania, Stafford, City of Fredericksburg17 min
Jul 31, 5:48 PM EDTSpecial Marine WarningLWX73 min
Jul 31, 6:01 PM EDTSpecial Marine WarningLWX59 min
Jul 31, 6:22 PM EDTSpecial Marine WarningLWX83 min
Jul 31, 6:41 PM EDTSpecial Marine WarningLWX58 min
Jul 31, 6:52 PM EDTSpecial Marine WarningLWX67 min
Jul 31, 7:11 PM EDTSpecial Marine WarningLWX69 min
Jul 31, 2:46 AM EDTCoastal Flood AdvisoryLWXAnne Arundel4 hr
Jul 31, 1:39 PM EDTSevere Thunderstorm WarningLWXAllegany36 min
Jul 31, 2:15 PM EDTSevere Thunderstorm WarningLWXAllegany30 min
Jul 31, 2:46 PM EDTAreal Flood WarningLWXAllegany2 hr
Jul 31, 4:45 PM EDTSevere Thunderstorm WarningLWXCalvert45 min
Jul 31, 5:21 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Calvert39 min
Jul 31, 5:56 PM EDTAreal Flood WarningLWXCalvert98 min
Jul 31, 5:58 PM EDTSevere Thunderstorm WarningLWXSaint Mary's46 min
Jul 31, 6:16 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Calvert44 min
Jul 31, 3:16 PM EDTSevere Thunderstorm WarningLWXHampshire44 min
Jul 31, 3:41 PM EDTAreal Flood WarningLWXGrant4 hr
Jul 31, 3:46 PM EDTSevere Thunderstorm WarningLWXHampshire44 min

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.