Alert archive / Maryland / Heat Advisories in 2021

Heat Advisory 1, NWS Baltimore/Washington

June 30, 20216 counties in Maryland

NWS Baltimore/Washington issued this heat advisory at Jun 30, 2021, 3:23 AM EDT for 6 counties in Maryland. It took effect at Jun 30, 2021, 12:00 PM EDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued: Jun 30, 2021, 3:23 AM EDT (07:23 UTC)
In effect from: Jun 30, 2021, 12:00 PM EDT
Expired: Jun 30, 2021, 7:03 PM EDT
In force: 7 hr
Issued by: NWS Baltimore/Washington

Counties Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Cecil County, MD, City of Baltimore, MD, Harford County, MD

The radar

The Sterling radar (KLWX), 95 km from the middle of the area, began a volume at 07:24 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

Pittsburgh, PA (KPIT), launched 00:00Z, 7.4 hours before the alert went out and 340 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1897 J/kg
Mixed-layer CIN: -11 J/kg
Mixed-layer LCL: 1542 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 37 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.4

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this heat advisory 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 heat advisory went out at Jun 29, 9:04 PM EDT, 6 hours 19 minutes earlier.

Area forecast discussion, Jun 29, 9:04 PM EDT, 6 hours 19 minutes before

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Hazardous weather outlook, Jun 29, 6:12 PM EDT, 9 hours 11 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 30, 4:07 AM EDT	Small Craft Advisory	LWX		22 hr
Jun 30, 2:23 PM EDT	Flash Flood Watch	LWX	Arlington, Culpeper, Fairfax, Fauquier, Greene, King George and 11 more	42 hr
Jun 30, 5:11 PM EDT	Severe Thunderstorm Warning	LWX	Frederick	34 min
Jun 30, 5:14 PM EDT	Severe Thunderstorm Warning	LWX	Rockingham, Shenandoah	24 min
Jun 30, 5:32 PM EDT	Severe Thunderstorm Warning	LWX	Frederick	23 min
Jun 30, 7:16 PM EDT	Special Marine Warning	LWX		89 min
Jun 30, 7:18 PM EDT	Special Marine Warning	LWX		87 min
Jun 30, 7:40 PM EDT	Special Marine Warning	LWX		95 min
Jun 30, 4:39 PM EDT	Severe Thunderstorm Warning	LWX	Allegany	36 min
Jun 30, 4:55 PM EDT	Severe Thunderstorm Warning	LWX	Allegany, Washington	21 min
Jun 30, 4:03 PM EDT	Severe Thunderstorm Warning	LWX	Hampshire, Mineral	27 min
Jun 30, 4:26 PM EDT	Severe Thunderstorm Warning	LWX	Hampshire, Mineral	16 min

Nearby

Heat Advisories in Maryland, 2021 Every heat advisory in 2021

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.