Alert archive / Maryland / Flash Flood Warnings in 2019
Flash Flood Warning 18, NWS Baltimore/Washington
NWS Baltimore/Washington issued this flash flood warning at Jul 8, 2019, 8:42 AM EDT for Howard County, Montgomery County, Maryland. It was in force for 2 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 8, 2019, 8:42 AM EDT (12:42 UTC)
- Expired
- Jul 8, 2019, 10:49 AM EDT
- In force
- 2 hr
- Issued by
- NWS Baltimore/Washington
- Area
- Storm-based polygon
- Flood severity
- None
Counties Howard County, MD, Montgomery County, MD
The radar
The Sterling radar (KLWX), 44 km from the middle of the area, began a volume at 12:42 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, 0.7 hours before the alert went out and 39 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.
- Mixed-layer CAPE
- 292 J/kg
- Mixed-layer CIN
- -7 J/kg
- Mixed-layer LCL
- 649 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 44 m²/s²
- 0-3 km storm-relative helicity
- 215 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 1.1
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 8, 3:59 AM EDT, 4 hours 43 minutes earlier.
Area forecast discussion, Jul 8, 3:59 AM EDT, 4 hours 43 minutes before
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
359 AM EDT Mon Jul 8 2019
.SYNOPSIS...
A weak cold front will move to our south today. High pressure
will then build north of the area into the middle of the week.
Another front will approach by week's end.
&&
.NEAR TERM /THROUGH TONIGHT/...
The main surface front is along the Mason-Dixon region. Multiple
showers and a few embedded thunderstorms had developed overnight
and moved across much of central Maryland, eastern West Virginia
Panhandle and far northern Virginia, prompting flood and flash
flood warnings. Rain amounts averaged one to three inches in
many locations in parts of Washington County, Berkeley and
Jefferson Counties, and Loudoun County. Lesser amounts occur
elsewhere in western Maryland and parts of northeast Virginia.
Showers currently exist across a large portion of northeast
Maryland and the eastern West Virginia Panhandle, as well as
southern Maryland.
A Flash Flood Watch remains in effect for central and northern
zones, as well as much of the metro areas through 6 am this
morning. As we enter into the heart of this morning, much of
heavier showers and any thunderstorms should diminish and lead
to a stray shower or drizzle. Dry air finally advances enough to
end precipitation. Highs today near 80.
Canadian high pressure dominates tonight. This will provide a
relatively cooler and less humid period with less cloud cover.
Highs in the 80s and lows in the 60s. Could be patchy fog in the
early morning hours, but that's pretty much the only fly in the
ointment.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
High pressure will dominate dry conditions on Tuesday. Cooler
and less humid conditions should continue. Highs will be in the
80s and lows in the 60s Tuesday night. Some patchy fog is
possible early Tuesday.
We remain dry on Wednesday, as high pressure slides overhead,
and eventually offshore by Wednesday night. This thanks to an
approaching cold front from the west, associated with a surface
low tracking well to our north across the Great Lakes into the
northeast. Highs on Wednesday will be in the mid to upper 80s
once again.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
A cold front will approach and move through our region some time
Thursday afternoon and into Friday. Ahead of the cold front a
southerly flow will lead to warm and moist air being advected into
our region. This will lead to CAPE values range from 1500 to 2500
along with 15 to 20 knots of shear. Showers and thunderstorms will
be a concern especially Thursday afternoon through early Friday. The
models disagreeing on the timing of the cold front the GFS being the
faster solution leading to Friday staying mainly dry while the Euro
keeps precipitation in place through Friday afternoon. This will be
a day to watch for potential severe weather especially pulse style
storms. Daytime temps during this period are expected to hover in
the mid to upper 80s.
Behind the frontal passage, a high pressure system will build into
our region from the south through the weekend. Temperatures are
forecast to hover in the mid 80s to low 80s with light winds out of
the west. Scattered showers and thunderstorms could be potential
Sunday afternoon due to upper level shortwave lift but models don't
have a strong signal on a widespread threat.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
Showers and a possible rumble of thunder over MRB and near IAD
through daybreak, plus a few showers near BWI and MTN terminals.
Otherwise, a cold front will push south and undercut warm moist
air will likely lead to IFR cigs, which may linger much of today
before breaking up late. Conditions will then become VFR by
tonight. Patchy fog possibly a concern late Monday night/early
Tuesday, but otherwise VFR for Tuesday.
VFR conditions expected Wednesday, as high pressure keeps
things dry. Not expecting any wind issues either, with light
winds expected both days.
A cold front on Thursday will bring showers and storms to the
region, which may lead to flight restrictions. However, am
expecting conditions to be primarily VFR outside of
thunderstorms.
&&
.MARINE...
Thunderstorm wind gusts are the main concern overnight.
Northerly flow behind slow moving cold front and ahead of
building high pressure likely leads to SCA gusts on much of the
waters today and this evening, so SCA has been raised. Winds
relax Tuesday as gradient relaxes while high builds in.
Winds remain below SCA criteria for at least Wednesday and
Thursday, as high pressure builds over the region on Wednesday,
before sliding offshore by Thursday. Winds on Thursday, while
slightly stronger out of the SW, should remain below SCA
criteria. However, could see some stronger gusts in any
thunderstorms over the waters.
&&
.HYDROLOGY...
A Flash Flood Watch remains in effect until 6 am this morning
for central and northeast Maryland, part of southern Maryland,
eastern West Virginia and northeast Virginia. One Flash Flood
Warning and two Flood Warnings are in effect through early this
morning.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Flash Flood Watch until 6 AM EDT early this morning for DCZ001.
MD...Flash Flood Watch until 6 AM EDT early this morning for
MDZ003>006-011-013-014-016-501>506.
VA...Flash Flood Watch until 6 AM EDT early this morning for VAZ028-
030-031-052>055-501-502-505-506.
WV...Flash Flood Watch until 6 AM EDT early this morning for
WVZ050>053-503-504.
MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ532-
533-540-541.
Small Craft Advisory until midnight EDT tonight for ANZ534-537-
542-543.
Small Craft Advisory until 2 PM EDT this afternoon for ANZ530-
531-538-539.
&&
SYNOPSIS...KLW
NEAR TERM...KLW
SHORT TERM...KLW
LONG TERM...JMG
AVIATION...KLW/JMG
MARINE...KLW/JMG
HYDROLOGY...KLWHazardous weather outlook, Jul 8, 6:22 AM EDT, 2 hours 20 minutes before
Hazardous Weather Outlook National Weather Service Baltimore MD/Washington DC 622 AM EDT Mon Jul 8 2019 ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-091030- 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- 622 AM EDT Mon Jul 8 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...Today and Tonight A Flash Flood Watch remains in effect through 10am this morning for the Washington and Baltimore Metropolitan areas. Scattered incidents of flooding are possible due to slow moving showers and thunderstorms. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotters are asked to report any severe weather or flooding to the National Weather Service via normal procedures. MDZ003>006-501>507-VAZ025>031-036>040-050-051-501>508-WVZ050>053- 055-501>506-091030- 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- 622 AM EDT Mon Jul 8 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...Today and Tonight A Flash Flood Watch remains in effect through 10am this morning for portions of northern Virginia, eastern West Virginia, and central and western Maryland. Scattered incidents of flooding are possible due to slow moving showers and thunderstorms. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotters are asked to report any flooding to the National Weather Service via normal procedures.
In the hours before
Local storm report, Jul 8, 7:31 AM EDT, 1 hour 11 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
731 AM EDT MON JUL 08 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0713 AM FLASH FLOOD FREDERICK 39.43N 77.42W
07/08/2019 FREDERICK MD LAW ENFORCEMENT
NUMEROUS ROADS FLOODED AND IMPASSIBLE IN THE CITY OF
FREDERICK.
&&
EVENT NUMBER LWX1905076
JELocal storm report, Jul 8, 8:09 AM EDT, 33 minutes before
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PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
819 AM EDT MON JUL 08 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0751 AM FLASH FLOOD 2 SSE BOYDS 39.16N 77.30W
07/08/2019 MONTGOMERY MD FIRE DEPT/RESCUE
VEHICLE STUCK IN HIGH WATER AT INTERSECTION OF
CORNFLOWER RD. AND KINGS CROSSING BLVD.
&&
EVENT NUMBER LWX1905078
CJLLocal storm report, Jul 8, 8:21 AM EDT, 21 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
821 AM EDT MON JUL 08 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0748 AM FLASH FLOOD 1 E BARNESVILLE 39.22N 77.37W
07/08/2019 MONTGOMERY MD FIRE DEPT/RESCUE
VEHICLE STUCK IN HIGH WATER AT INTERSECTION OF W OLD
BALTIMORE RD. AND BARNESVILLE RD.
&&
EVENT NUMBER LWX1905079
CJLLocal storm report, Jul 8, 8:24 AM EDT, 18 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
824 AM EDT MON JUL 08 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0809 AM FLASH FLOOD 2 W NORTH POTOMAC 39.09N 77.28W
07/08/2019 MONTGOMERY MD FIRE DEPT/RESCUE
VEHICLE STUCK IN HIGH WATER AT INTERSECTION OF TURKEY
FOOT RD. AND FALLING LEAF DR.
&&
EVENT NUMBER LWX1905080
CJLLocal storm report, Jul 8, 8:26 AM EDT, 16 minutes before
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</html>The office that day
Everything else NWS Baltimore/Washington issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 8, 12:48 AM EDT | Severe Thunderstorm Warning | LWX | Loudoun | 42 min |
| Jul 8, 2:22 AM EDT | Areal Flood Warning | LWX | Loudoun | 6 hr |
| Jul 8, 6:56 AM EDT | Areal Flood Warning | LWX | Loudoun | 8 hr |
| Jul 8, 7:46 AM EDT | Flash Flood Warning | LWX | Arlington, Fairfax, Loudoun, City of Falls Church | 5 hr |
| Jul 8, 8:20 AM EDT | Flash Flood Warning | LWX | Arlington, Fairfax, City of Alexandria, City of Fairfax | 5 hr |
| Jul 8, 9:21 AM EDT | Flash Flood Warning | LWX | Arlington, Fairfax, City of Alexandria | 114 min |
| Jul 8, 10:32 AM EDT | Special Marine Warning | LWX | 118 min | |
| Jul 8, 11:43 AM EDT | Coastal Flood Advisory | LWX | Arlington, City of Alexandria, City of Falls Church | 16 hr |
| Jul 8, 12:43 PM EDT | Special Marine Warning | LWX | 81 min | |
| Jul 8, 12:53 PM EDT | Areal Flood Warning | LWX | Arlington, Fairfax, City of Alexandria, City of Fairfax, City of Falls Church | 5 hr |
| Jul 7, 11:11 PM EDT | Areal Flood Warning | LWX | Allegany | 2 hr |
| Jul 7, 11:24 PM EDT | Areal Flood Warning | LWX | Frederick, Washington | 12 hr |
| Jul 8, 12:27 AM EDT | Flash Flood Warning | LWX | Washington | 4 hr |
| Jul 8, 5:35 AM EDT | Areal Flood Warning | LWX | Frederick, Washington | 8 hr |
| Jul 8, 6:41 AM EDT | Flash Flood Warning | LWX | Frederick | 3 hr |
| Jul 8, 7:10 AM EDT | Flash Flood Warning | LWX | Frederick, Montgomery | 6 hr |
| Jul 8, 7:40 AM EDT | Areal Flood Warning | LWX | Baltimore, Carroll, Frederick | 8 hr |
| Jul 8, 7:49 AM EDT | River Flood Warning | LWX | Montgomery | 15 hr |
| Jul 8, 8:25 AM EDT | Areal Flood Warning | LWX | Howard | 4 hr |
| Jul 8, 9:07 AM EDT | Flash Flood Warning | LWX | Charles, Prince George's | 4 hr |
| Jul 8, 11:17 AM EDT | Flash Flood Warning | LWX | Saint Mary's | 3 hr |
| Jul 8, 11:18 AM EDT | Severe Thunderstorm Warning | LWX | Saint Mary's | 42 min |
| Jul 8, 11:21 AM EDT | Areal Flood Warning | LWX | Calvert | 3 hr |
| Jul 8, 12:23 PM EDT | Areal Flood Warning | LWX | Anne Arundel, Howard | 4 hr |
| Jul 8, 12:50 PM EDT | Areal Flood Warning | LWX | Montgomery, Prince George's | 8 hr |
| Jul 8, 12:57 PM EDT | Areal Flood Warning | LWX | Charles, Prince George's, Saint Mary's | 5 hr |
| Jul 8, 6:40 PM EDT | Areal Flood Warning | LWX | Prince George's | 15 hr |
| Jul 8, 7:13 PM EDT | Areal Flood Warning | LWX | Saint Mary's | 4 hr |
| Jul 8, 12:42 AM EDT | Flash Flood Warning | LWX | Jefferson | 3 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.