Alert archive / Maryland / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 155, NWS Baltimore/Washington

June 30, 2015Loudoun County, Virginia; Frederick County, Washington County, Maryland; Berkeley County, Jefferson County, West Virginia

NWS Baltimore/Washington issued this severe thunderstorm warning at Jun 30, 2015, 9:37 PM EDT for Loudoun County, Virginia; Frederick County, Washington County, Maryland; Berkeley County, Jefferson County, West Virginia. It was in force for 38 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
Jun 30, 2015, 9:37 PM EDT (01:37 UTC)
Expired
Jun 30, 2015, 10:15 PM EDT
In force
38 min
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon

Counties Frederick County, MD, Washington County, MD, Loudoun County, VA, Berkeley County, WV, Jefferson County, WV

The radar

The Sterling radar (KLWX), 51 km from the middle of the area, began a volume at 01:40 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 57 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 2015-07-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 665 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 2015-07-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 100 square meters per square second.19395878Sfc1 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
665 J/kg
Mixed-layer CIN
-18 J/kg
Mixed-layer LCL
1402 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
100 m²/s²
0-3 km storm-relative helicity
127 m²/s²
Significant tornado parameter
0.1
Supercell composite
2.8

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 Jun 30, 6:33 PM EDT, 3 hours 4 minutes earlier.

Area forecast discussion, Jun 30, 6:33 PM EDT, 3 hours 4 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
633 PM EDT TUE JUN 30 2015

.SYNOPSIS...
LOW PRESSURE WILL SLIDE EASTWARD OVER THE EASTERN GREAT LAKES
TODAY. A COLD FRONT WILL SLIDE SOUTHEAST INTO THE MID ATLANTIC
LATE ON WEDNESDAY...AND THEN STALL ACROSS THE REGION ON THURSDAY.
THE STALLED FRONT WILL LINGER IN THE AREA THROUGH THE WEEKEND
BEFORE LIFTING NORTHWARD AGAIN ON MONDAY.

&&

.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
HV CANCELLED SEVERE TSTM WATCHES FOR EVERYWHERE EAST OF THE BLUE
RDIGE XCPT FOR CALVERT AND STM ARYS CNTYS...AS WELL AS THE NRN
SHEN VALLEY/MRB-HGR AREA. THERES A LEE TROF THAT STILL MAY TRIGGER
A STORM OR TWO. THAT ACCOUNTS FOR THE ERN AREA. TO THE
WEST...THERES A DYING COMPLEX OF TSRA. WE DONT WANT TO DROP A
WATCH PREMATURELY TIL WERE CERTAIN WHAT ITS EVOLUTION WL BE.

THE CMPLX LKLY WL AFFECT THE CWFA THIS EVNG...PERHAPS INTO THE
OVNGT HRS. WHILE THERE SHOULD BE AN OVERALL EASTWARD PROGRESSION
AND DIURNAL WEAKENING OF ACTIVITY THIS EVENING...MODELS MAINTAIN
ELEVATED INSTBY OVERNIGHT AND DECENT SHEAR TNGT. MID/UPPER LEVEL
TROUGH WILL BE APPROACHING TOWARD DAYBREAK. THEREFORE SOME SHOWERS
AND STORMS MAY LINGER WELL INTO THE OVERNIGHT PERIOD. MIN TEMPS IN
THE LOWER/MID 60S WEST AND UPPER 60S/LOWER 70S EAST.

THE TROF WL EMERGE OVER THE ERN SHORE BY WED MRNG. A CDFNT WL BE
APPROACHING...ATTENDENT FM LOPRES THAT WL BE TRACKING ACRS QUEBEC
BY THAT TIME. HWVR...THE CDFNT LOOKS QUITE WEAK...AND AM
STRUGGLING TO FIND FORCING MECHANISMS. AMS WL STILL BE QUITE MOIST
BUT NOT THAT UNSTBL. MID LVL LAPSE RATES WL BE DECENT. WL HOLD
ONTO LOW END CHC POPS...HIER THAN MAV/MET...AND CONT TIL SUNSET.

AM NOT MAKING ANY SUBSTANTIVE CHANGES TO TEMPS ATTM. WL STILL BE
IN THE WARM SECTOR TMRW...SO TEMPS WL BE SLGTLY MUGGY WITH HIGHS
MID-UPR 80S.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
LOW PRESSURE WILL MOVE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY
THURSDAY MORNING WHILE A COLD FRONT REMAINS STALLED ACROSS MUCH OF
THE EASTERN SEABOARD. SHOWERS ARE EXPECTED TO MOVE INTO THE
HIGHLANDS THURSDAY AFTERNOON AS LOW PRESSURE MOVES ALONG THE STALLED
FRONTAL BOUNDARY. FCST MODELS HAVE SLOWED DOWN THE PROGRESSION OF
SHOWERS MOVING INTO THE REGION. SHOWERS WILL SPREAD ACROSS THE MID-
ATLANTIC THURSDAY NIGHT. HEAVY SHOWERS ARE EXPECTED AS ENHANCED LIFT
OCCURS IN THE ENTRANCE REGION OF A UPPER LEVEL JET. DUE TO THE TIME
OF DAY AND LACK OF INSTABILITY ALOFT...THUNDERSTORMS ARE NOT
EXPECTED AT THIS TIME.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
MAIN STORY THROUGH THE EXTENDED IS CONT CHCS FOR UNSETTLED WX...AS
STUBBORN FRONTAL BOUNDARY REMAINS NEAR/OVER OUR AREA. THERE REMAINS
CONSIDERABLE UNCERTAINTY AND MODEL DISAGREEMENT WITH REGARDS TO
FRONTAL LOCATION THROUGH THE EXTENDED. AS SUCH...IT IS DIFFICULT
DETERMINE THE SPATIOTEMPORAL EXTENT OF ANY ACTIVITY AND DETERMINE
CONVECTIVE VS SHOWER CHCS.

MILLION DOLLAR QUESTION IS WHAT WILL THE WX BE LIKE ON SAT...FOR NOW
HAVE KEPT CHC POPS AND THUNDER...THOUGH THERE IS CERTAINLY BUST
POTENTIAL WITH THIS...AS FRONT COULD BE FAR ENOUGH TO OUR
SOUTH...WHICH WOULD LIMIT INSTABILITY (ELEVATED).

AS MENTIONED YESTERDAY...TEMPS PROGGED TO REMAIN AOB CLIMO NORMS
THROUGH THE EXTENDED...WITH A GRADUAL WARMING TREND THROUGH THE
PERIOD. DEWPOINTS ALSO EXPECTED TO REMAIN AOB 70F...SO NOT EXPECTING
CONDITIONS TO BE VERY OPPRESSIVE.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDS PREVAILING ATTM. TSRA DVLPMNT WL BE IN THE
NEIGHBORHOOD...BUT CONFIDENCE IN IMPACT AT A TERMINAL A BIT MORE
UNCERTAIN. AM USING VCTS TO COVER THRU EVENING PUSH...AND WL INCL
A TEMPO FOR SPECIFICS ONCE ITS MORE CERTAIN A TERMINAL WL BE
DIRECTLY AFFECTED. POTL FOR WINDS GUSTS 40-50 KT IN THE STRONGEST
STORMS.

BELIEVE OVERALL INTENSITY WL DECLINE OVNGT...BUT SUSPECT THERE WL
BE SOME ACTIVITY. FLGT RESTRICTIONS WL THEREFORE REMAIN PSBL...
BUT MORE LKLY MVFR. HWVR...CONFIDENCE NOT HIGH IN STORM EVOLUTION.

TSRA CVRG LOOKING MUCH LWR ON WED...AS TROF WL BE EAST OF
TERMINALS. A WEAK CDFNT WL BE DROPPING SWD IN THE AFTN-EVNG. ITS
ENTIRELY PSBL THAT THERE WL BE NO TSRA AT ALL. TAFS VFR W/ CIGS
BKN-OVC050-060.

SUB-VFR CONDITIONS POSSIBLE THURSDAY NIGHT AS RAIN MOVES INTO THE
REGION

MAIN CONCERN THROUGH EXTENDED IS POTENTIAL FOR SCATTERED
THUNDERSTORMS EACH DAY...WITH SUB-VFR CONDS POSSIBLE NEAR TSTMS. VFR
CONDS EXPECTED OUTSIDE OF TSTMS.

&&

.MARINE...
S/SE CHANNELING OCCURING OVER THE WATERS ATTM. SCA REMAINS IN
EFFECT. SEVERE THUNDERSTORM WATCH ALS IN EFFECT FOR ALL WATERS FOR
THE POTENTIAL OF STRONG WIND GUSTS. GRADIENT WINDS WILL DIMINSH
OVERNIGHT. SW FLOW THROUGH WED AROUND 10 KT...ALTHOUGH MAY BE
SLIGHTLY STRONGER TOWARD TANGIER SOUND. LOWER CHANCE OF STORMS
THROUGH WED.

SHOWERS WILL OVERSPREAD THE REGION THURSDAY NIGHT AND MAY CAUSE
REDUCED VSBYS.

WINDS EXPECTED TO REMAIN BELOW SCA CRITERIA THROUGH THE
EXTENDED...THOUGH WILL NEED TO MONITOR AS FRONT WILL BE NEAR AREA
EACH DAY. SHOWERS AND TSTMS ARE ALSO POSSIBLE EACH DAY...WHICH
COULD IMPACT MARINE CONCERNS

&&

.TIDES/COASTAL FLOODING...
WATER LVLS RUNNING ABT A FOOT ABV ASTRO NORMS. THE LOWER OF THE
TWO HIGH TIDES ROLLING IN NOW...WHICH WL KEEP LEVELS BELOW ADVY
CRITERIA. HWVR...ISSUES WUD RESULT FROM THE NEXT TIDE...MIDNGT TO
NOON. TOO SOON TO ISSUE ADVY ATTM...BUT ONE MAY BE REQD BEFORE
EVNG OVER.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT WEDNESDAY FOR ANZ531>534-
     537-539>543.
     SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ530-
     535-536-538.

&&

SYNOPSIS...HTS
NEAR TERM...HTS
SHORT TERM...HAS
LONG TERM...MSE
AVIATION...HTS/HAS/MSE
MARINE...HTS/HAS/MSE
TIDES/COASTAL FLOODING...HTS
Hazardous weather outlook, Jun 30, 9:04 PM EDT, 33 minutes before
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In the hours before

Local storm report, Jun 30, 5:16 PM EDT, 4 hours 21 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
516 PM EDT TUE JUN 30 2015

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

0427 PM     TSTM WND DMG     2 NE DOWELL             38.37N  76.43W
06/30/2015                   CALVERT            MD   911 CALL CENTER

            TREE DOWN NEAR 100 BLOCK OF THUNDERBIRD DR

&&

EVENT NUMBER LWX1500644

MSE
Local storm report, Jun 30, 5:30 PM EDT, 4 hours 7 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
530 PM EDT TUE JUN 30 2015

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

0505 PM     MARINE TSTM WIND 11 SSE LOVE POINT       38.90N  76.21W
06/30/2015  M48 MPH          ANZ540             MD   MESONET

&&

EVENT NUMBER LWX1500645

SMZ
Local storm report, Jun 30, 8:09 PM EDT, 1 hour 28 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
809 PM EDT TUE JUN 30 2015

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

0312 PM     MARINE TSTM WIND 3 W SPARROWS POINT      39.22N  76.53W
06/30/2015  M44 MPH          ANZ538             MD   BUOY

0436 PM     MARINE TSTM WIND 3 E CALVERT CLIFFS      38.43N  76.39W
06/30/2015  M49 MPH          ANZ533             MD   BUOY

0448 PM     MARINE TSTM WIND 7 SSE SAINT GEORGE ISLA 38.01N  76.45W
06/30/2015  M44 MPH          ANZ537             MD   BUOY

0457 PM     MARINE TSTM WIND 15 ESE GALESVILLE       38.78N  76.25W
06/30/2015  M41 MPH          ANZ541             MD   MESONET

0501 PM     MARINE TSTM WIND 1 SE EASTPORT           38.96N  76.46W
06/30/2015  M41 MPH          ANZ532             MD   BUOY

0502 PM     MARINE TSTM WIND 1 E BAY RIDGE           38.94N  76.44W
06/30/2015  M47 MPH          ANZ532             MD   BUOY

&&

EVENT NUMBER LWX1500646
EVENT NUMBER LWX1500647
EVENT NUMBER LWX1500648
EVENT NUMBER LWX1500649
EVENT NUMBER LWX1500650
EVENT NUMBER LWX1500651

SMZ
Local storm report, Jun 30, 9:00 PM EDT, 37 minutes before
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Local storm report, Jun 30, 9:35 PM EDT, 2 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jun 30, 8:31 PM EDTSevere Thunderstorm WarningLWXPage, Rockingham, Shenandoah19 min
Jun 30, 9:52 PM EDTFlash Flood WarningLWXFrederick4 hr
Jun 30, 9:55 PM EDTSevere Thunderstorm WarningLWXNelson50 min
Jun 30, 10:28 PM EDTSevere Thunderstorm WarningLWXAlbemarle, Nelson, City of Charlottesville47 min
Jun 30, 11:08 PM EDTCoastal Flood AdvisoryLWXArlington, Fairfax, City of Alexandria, City of Fairfax, City of Falls Church11 hr
Jun 30, 11:17 PM EDTSpecial Marine WarningLWX58 min
Jun 30, 11:36 PM EDTSevere Thunderstorm WarningLWXCulpeper, Fauquier, Loudoun, Prince William, Rappahannock24 min
Jun 30, 11:44 PM EDTSevere Thunderstorm WarningLWXAlbemarle, Culpeper, Madison, Orange, Spotsylvania31 min
Jun 30, 11:55 PM EDTSevere Thunderstorm WarningLWXFairfax, Fauquier, Loudoun, Prince William, City of Manassas Park35 min
Jun 30, 11:57 PM EDTSpecial Marine WarningLWX93 min
Jul 1, 12:10 AM EDTSpecial Marine WarningLWX65 min
Jul 1, 12:11 AM EDTSevere Thunderstorm WarningLWXFairfax, Prince William, Stafford, City of Alexandria34 min
Jul 1, 12:21 AM EDTSpecial Marine WarningLWX54 min
Jul 1, 12:22 AM EDTSpecial Marine WarningLWX68 min
Jul 1, 12:33 AM EDTSevere Thunderstorm WarningLWXFairfax, Fauquier, Prince William, Stafford, City of Fairfax, City of Manassas and 1 more27 min
Jul 1, 12:47 AM EDTSevere Thunderstorm WarningLWXArlington, Fairfax, City of Alexandria28 min
Jul 1, 1:02 AM EDTSpecial Marine WarningLWX88 min
Jul 1, 2:23 AM EDTSpecial Marine WarningLWX97 min
Jul 1, 7:45 PM EDTSpecial Marine WarningLWX90 min
Jun 30, 10:02 PM EDTSevere Thunderstorm WarningLWXCarroll, Frederick, Washington43 min
Jul 1, 12:10 AM EDTSevere Thunderstorm WarningLWXAnne Arundel, Calvert, Charles, Prince George's, Saint Mary's35 min
Jul 1, 12:43 AM EDTSevere Thunderstorm WarningLWXAnne Arundel, Calvert, Prince George's32 min
Jul 1, 1:00 AM EDTSevere Thunderstorm WarningLWXAnne Arundel, Baltimore, Howard, Montgomery, Prince George's, City of Baltimore30 min
Jul 1, 1:24 AM EDTSevere Thunderstorm WarningLWXAnne Arundel, Baltimore, Carroll, Harford, Howard, Montgomery and 2 more36 min
Jul 1, 1:32 AM EDTFlash Flood WarningLWXAnne Arundel, Baltimore, Harford, Howard, City of Baltimore118 min
Jul 1, 1:37 AM EDTSevere Thunderstorm WarningLWXBaltimore, Harford23 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2015Severe Thunderstorm Warnings in West Virginia, 2015Severe Thunderstorm Warnings in Virginia, 2015Every severe thunderstorm warning in 2015

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.