Alert archive / Maryland / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 116, NWS Baltimore/Washington

July 1, 2017Baltimore County, Harford County, Maryland

NWS Baltimore/Washington issued this severe thunderstorm warning at Jul 1, 2017, 3:56 PM EDT for Baltimore County, Harford County, Maryland. It was in force for 64 min. 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 1, 2017, 3:56 PM EDT (19:56 UTC)
Expired
Jul 1, 2017, 5:00 PM EDT
In force
64 min
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Baltimore County, MD, Harford County, MD

The radar

The Sterling radar (KLWX), 105 km from the middle of the area, began a volume at 20:00 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 watch it was issued in

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

IssuedProductOfficeLasted
Jul 1, 1:34 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.9 hours before the alert went out and 101 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 2017-07-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 160 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 2017-07-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 95 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
160 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
564 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
95 m²/s²
0-3 km storm-relative helicity
105 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Jul 1, 3:13 PM EDT, 43 minutes earlier.

Area forecast discussion, Jul 1, 3:13 PM EDT, 43 minutes before
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
313 PM EDT Sat Jul 1 2017

.SYNOPSIS...
A cold front will pass through the area this evening. Another
cold front will move into the area Monday into Tuesday. High
pressure will develop over the Atlantic for Wednesday before low
pressure and its associated cold front possibly impacts the
region Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Main concerns are in the next few hours as squall line ahead of
the cold front approaching from the northwest. Best trigger and
shear is north, while moisture/CAPE increases south, but
without trigger down south very far, expect most severe to stay
in central and northern portion of CWA, where severe box is
currently positioned. Do not expect much beyond the initial line
so will likely be able to cancel much of the box early.

Otherwise, drier air will begin to push into the region this
evening behind the front, resulting in lowering dew points and
ultimately a slightly more comfortable night than last night.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Dew points will be noticeably lower on Sunday, but temperatures
will remain quite warm, with highs similar to today's expected.
With much less forcing and lower dew points, expect much less
thunderstorm coverage, but meso models are showing some isolated
convection during the afternoon and evening, possibly associated
with a jet max. This will need to be monitored.

Not much air mass change from Sunday to Monday, though there is
a modest increase in moisture ahead of the next front. This will
couple with another approaching front to result in a slightly
more widespread threat of thunderstorms Monday
afternoon/evening, along with an isolated/marginal severe
threat. This looks more likely to stay NW of the metro, but some
lingering activity could reach the metro itself at night. Highs
Monday will again reach similar readings to today (Saturday).

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
A boundary will stall over our area on Tuesday into Wednesday
as a low pressure develops south of the Great Lakes. Southerly
flow will advect moisture into our area during this time and
some diurnally driven showers and thunderstorms are possible
Tuesday July 4th and Wednesday afternoon into the evening.

The low will move east-northeast across the Ohio Valley and
will lift the boundary as a warm front late Wednesday night into
Thursday as it approaches. Showers and thunderstorms possible
as low pressure moves across our north and into New England
Thursday into Friday. It will push a cold front through our area
early on Friday and another one will move through early on
Saturday. Conditions should improve behind this front on
Saturday.

High temperatures during this period will be near 90 degrees
along the I-95 corridor, upper 70s and low to mid 80s elsewhere.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
Main concern next few hours is thunderstorms, potentially
severe, affecting the terminals, with damaging winds and large
hail possible along with brief IFR cigs/vis in heavy rain. After
that's over, it should be VFR through Monday night, as dry air
moving in should prevent fog and we also don't expect low
clouds either. Could still be a stray thunderstorm Sunday
afternoon/evening as well as Monday afternoon/evening.

Dry/VFR conditions expected early on Tuesday. Maybe a few
showers and thunderstorms possible in the afternoon as a
boundary stalls over us. A few showers and thunderstorms
possible again Wednesday and Thursday with boundary stalling and
slowly moving away from us. Sub-VFR periods possible Tuesday
afternoon into Thursday.

&&

.MARINE...
SCA continues until 9PM for lingering SW winds ahead of
approaching front. Special Marine Warnings also affecting the
waters as storms move in this afternoon. After that, looks like
we stay sub-SCA through Monday night with weak pressure gradient
between fronts.

Dry conditions expected early on Tuesday. Maybe a few showers
and thunderstorms possible in the afternoon as a boundary stalls
over us. A few showers and thunderstorms possible again
Wednesday and Thursday with boundary stalling and slowly moving
away from us. Wind gusts will increase on Thursday, maybe
needing a small craft advisory.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 9 PM EDT this evening for
     ANZ530>543.

&&

SYNOPSIS...RCM
NEAR TERM...RCM
SHORT TERM...RCM
LONG TERM...IMR
AVIATION...IMR/RCM
MARINE...IMR/RCM
Hazardous weather outlook, Jul 1, 1:37 PM EDT, 2 hours 19 minutes before
Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
137 PM EDT Sat Jul 1 2017

ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-021745-
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-
137 PM EDT Sat Jul 1 2017

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

A severe thunderstorm watch is in effect until 9 PM EDT for
portions of northern Virginia, Maryland and the District of
Columbia. Isolated severe thunderstorms with damaging wind gusts
and large hail are possible this afternoon and evening.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and evening.

MDZ003>006-501>507-VAZ025>031-036>040-050-051-501>508-WVZ050>053-
055-501>506-021745-
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-
137 PM EDT Sat Jul 1 2017

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

A severe thunderstorm watch is in effect for portions of northern
Virginia and Maryland until 9 PM EDT. Isolated severe
thunderstorms with damaging wind gusts and large hail are possible
this afternoon and evening.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and evening.

In the hours before

Local storm report, Jul 1, 3:25 PM EDT, 31 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
325 PM EDT SAT JUL 01 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0245 PM     TSTM WND DMG     2 NW ARCOLA             38.98N  77.56W
07/01/2017                   LOUDOUN            VA   911 CALL CENTER

            TREE DOWN AT FLEETWOOD RD AND EVERFIELD DR

&&

EVENT NUMBER LWX1702205

SMZ
Local storm report, Jul 1, 3:38 PM EDT, 18 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jul 1, 2:38 PM EDTSevere Thunderstorm WarningLWXFairfax, Fauquier, Loudoun, Prince William, City of Fairfax41 min
Jul 1, 2:45 PM EDTSpecial Marine WarningLWX90 min
Jul 1, 3:00 PM EDTSevere Thunderstorm WarningLWXArlington, Fairfax, City of Falls Church45 min
Jul 1, 3:07 PM EDTSpecial Marine WarningLWX113 min
Jul 1, 3:34 PM EDTSpecial Marine WarningLWX86 min
Jul 1, 3:35 PM EDTSpecial Marine WarningLWX85 min
Jul 1, 4:12 PM EDTSpecial Marine WarningLWX2 hr
Jul 1, 4:46 PM EDTSpecial Marine WarningLWX59 min
Jul 1, 4:52 PM EDTSpecial Marine WarningLWX53 min
Jul 1, 5:47 PM EDTSpecial Marine WarningLWX58 min
Jul 1, 6:06 PM EDTSpecial Marine WarningLWX114 min
Jul 1, 6:19 PM EDTSpecial Marine WarningLWX86 min
Jul 1, 6:40 PM EDTSpecial Marine WarningLWX95 min
Jul 1, 7:11 PM EDTSpecial Marine WarningLWX94 min
Jul 1, 7:45 PM EDTSpecial Marine WarningLWX2 hr
Jul 1, 3:01 PM EDTSevere Thunderstorm WarningLWXCarroll, Frederick26 min
Jul 1, 3:31 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Howard, Montgomery, Prince George's44 min
Jul 1, 4:01 PM EDTSevere Thunderstorm WarningLWXAnne Arundel34 min
Jul 1, 4:33 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Calvert, Prince George's42 min
Jul 1, 6:02 PM EDTSevere Thunderstorm WarningLWXCalvert43 min
Jul 1, 7:22 PM EDTSevere Thunderstorm WarningLWXSaint Mary's38 min
Jul 1, 7:51 PM EDTSevere Thunderstorm WarningLWXSaint Mary's28 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2017Every severe thunderstorm warning in 2017

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.