Hazardous Heat Across the Western U.S.; Heavy Rain and Flooding in the Southwest and Western Gulf Coast

Dangerous heat will persist over portions of interior California, the Great Basin, and the northern Rockies through Thursday. Heat will gradually spread into the northern Plains today. Across the western Gulf Coast, heavy to excessive rainfall will persist through mid-week. Additionally, the Southwest Monsoon will continue to bring a flash flooding threat to the Four Corners Region this week. Read More >

Overview

A waterspout touched down in the Chesapeake Bay just west of Smith Island just before 7:20 PM on 8/4. The waterspout came ashore and tracked across the western and northern portion of Smith Island as a high-end EF-1 tornado, causing significant damage to a bed and breakfast and several other structures. There were no fatalities, but a resident of a mobile home was injured.

Meteorologically speaking, this was an extremely unusual setup for a tornado with winds in excess of 100 mph to occur. While LCLs were low (temperatures were in the mid-upper 80s with low 80s dew points), several other environmental parameters did not seem favorable for tornadoes. With weak wind fields throughout the atmospheric profile, effective SRH values were no higher than 60 m2/s2. However, there was a decent amount of veering from the surface to 1-2 km AGL (see wind profiler data in Environment section). There was plenty of instability present given the low 80s dew points. While we often look for localized backing in the surface wind field to identify areas that may see enhanced SRH, this was not present in this case (S-SSW winds at Tangier Sound Light right before the tornado hit Smith Island). The cell that went on to produce the tornado split into a left mover and right mover. Perhaps the most unusual aspect of this case is that the right mover quickly dissipated and the left mover not only produced a tornado, but one that was more than just a quick spin-up. In addition, despite the fact that the storm was a left mover, video showed that the tornado had cyclonic rotation. The storm also had a peak rotational velocity of around 10 knots, which made it exceptionally difficult to see on radar. The most likely reason for this is that nearly all of the rotation (and tornado) occurred below the radar beam (~5000 feet AGL from KDOX and out of range from TADW). With classic supercells, there is a deep mesocyclone present with rotation visible with radar that is often above 10000 feet AGL.

Tornado
Photos
Radar
Environment

Tornadoes:

Tornado - Smith Island
SOMERSET COUNTY, MARYLAND

Date	8/4/2022
Time (Local)	7:20-7:27 PM
EF Rating	EF-1
Est. Peak Winds	110 mph
Path Length	2.2 miles
Max Width	100 yards
Injuries/Deaths	1/0
Summary: The following information was provided by local residents and news outlets. A waterspout touched down in the Chesapeake Bay just to the southwest of Smith Island before moving ashore and capsizing several boats longer than 25 feet in Sheep Pen Gut. After crossing Sheep Pen Gut, the tornado crossed Marsh Road just to the northwest of Calvary Church, where a power pole was downed. The tornado tracked to the north-northeast and reached high-end EF-1 intensity with estimated winds of 110 mph when it arrived at the intersection of Marsh Road and Smith Island Road. The tornado ripped the roof off of Island Time Bed and Breakfast and another block building right after this point. In addition, a mobile home just north of these two buildings was completely destroyed and one resident was injured. Multiple trees were downed in this area as well. The tornado continued to track to the north-northeast, crossing Smith Island Road and moving well into the marsh east of Smith Island Road. The tornado weakened some before reaching the north side of the island, but still severely damaged an outbuilding just west of the local post office. It also overturned a golf cart, which fell into Levering Creek. The tornado moved back into the Chesapeake Bay after entering Levering Creek.

Track Map

The Enhanced Fujita (EF) Scale classifies tornadoes into the following categories:

EF0 Weak 65-85 mph	EF1 Moderate 86-110 mph	EF2 Significant 111-135 mph	EF3 Severe 136-165 mph	EF4 Extreme 166-200 mph	EF5 Catastrophic 200+ mph

Photos

Selected Photos from Smith Island


Significant Damage to Bed and Breakfast	Significant Damage to Mobile Home	Significant Damage to Block Building

Radar

KDOX Radar Loop

Radar Loop of 0.5° Reflectivity (left) and Storm Relative Velocity (right) from 7:11 to 7:33 PM in ~3 minute increments

Environment

Synoptic summary.


18z/2 PM WPC Surface Analysis	00z/8 PM WPC Surface Analysis	00z/8 PM 500mb Analysis

Near-storm environment soundings.


00z/8 PM KWAL Observed Sounding	21z/5 PM NAM 3 hr Forecast Sounding for near Smith Island	22z-00z/6-8 PM Profiler Data from Horn Point (near Cambridge, MD)