Heavy Rainfall to Bring Flooding Threat to California; Heavy Snow in the Sierra

A strong atmospheric river will bring heavy rainfall to California through the holiday week. The heaviest rainfall is expected on Wednesday in the Los Angeles Basin. Flash and urban flooding is possible. A prolonged heavy snowfall is expected in the Sierra Nevada from the atmospheric river, raising concerns for major snow‐load impacts. Travel may be difficult to impossible over the passes. Read More >

Overview

The Tennessee Valley and the Southern Appalachian region experienced high winds from the afternoon of Wednesday, March 30 through the afternoon of Thursday, March 31. The combination of high winds, dry ground (fuels), and low relative humidity produced a dangerous fire weather situation. Numerous wildfires started and quickly spread throughout East Tennessee and southwest Virginia as a result of these conditions. The most significant fire was at Hatcher Mountain near Wears Valley, TN, which prompted evacuations, burned over 3,000 acres, and damaged over 100 homes.

Photos & Video
Satellite and Radar
Storm Reports
Environment

Photos & Video


Hatcher Mountain Aerial View (Courtesy TN Dept of Agriculture)	Hatcher Mountain Aerial View (Courtesy TEMA)	Wildfire Ground View (Courtesy THP Knoxville)	Wildfire Ground View (Courtesy TN Dept of Agriculture)


Wildfire Ground View (Courtesy THP)	Damage from Wildfire (Courtesy TN Dept of Agriculture)	Hatcher Mountain Fire (Courtesy TN State Representative Jason Zachary)	Trees on Powerlines in Red Bank, TN (Courtesy Nicolas Connally via Brian Smith WTVC-TV)

Satellite and Radar


Radar image showing the smoke plume of the Hatcher Mountain wildfire during the afternoon of Wednesday, March 30. Courtesy of Chris Michaels, WSLS Roanoke, VA.	The Hatcher Mountain wildfire was easily identified using the GOES satellite Fire Temperature product, depicted as the bright red area in Sevier County, just north of Wears Valley. This image is from around 4 pm on Wednesday, March 30.

Storm Reports

Below is a spatial interpolation of maximum wind gusts via GIS followed by a text version of the reports.

GIS Spatial Interpolation of Maximum Wind Reports

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE MORRISTOWN TN
944 AM EDT THU MAR 31 2022

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

0315 AM     NON-TSTM WND GST 3 N LAKE FOREST         35.97N 83.87W
03/31/2022  M47 MPH          KNOX               TN   AWOS

            AWOS STATION KDKX KNOXVILLE DOWNTO.

0305 AM     NON-TSTM WND GST 1 NNW ALCOA             35.81N 83.99W
03/31/2022  M64 MPH          BLOUNT             TN   ASOS

            REPORTED AT KNOXVILLE AIRPORT.

0300 AM     NON-TSTM WND GST 3 ESE WEARS VALLEY      35.70N 83.61W
03/31/2022  M85 MPH          SEVIER             TN   MESONET

            PEAK WIND FROM GSMNP WIND TOWER AT COVE
            MOUNTAIN.

0255 AM     NON-TSTM WND GST 2 NW MADISONVILLE       35.55N 84.38W
03/31/2022  M58 MPH          MONROE             TN   AWOS

            REPORTED AT MONROE COUNTY AIRPORT.

0235 AM     NON-TSTM WND GST 4 SSE ATHENS            35.40N 84.57W
03/31/2022  M48 MPH          MCMINN             TN   AWOS

            AWOS STATION KMMI ATHENS.

0233 AM     TSTM WND DMG     5 N BRAYTON             35.54N 85.20W
03/31/2022                   BLEDSOE            TN   PUBLIC

            A FEW TREES DOWN.

0231 AM     NON-TSTM WND GST 1 W LENOIR CITY         35.80N 84.30W
03/31/2022  E53 MPH          LOUDON             TN   PUBLIC



0229 AM     TSTM WND DMG     5 NE PALIO              35.53N 85.26W
03/31/2022                   BLEDSOE            TN   PUBLIC

            A FEW TREES DOWN.

0215 AM     NON-TSTM WND GST 2 ENE JACKSBORO         36.34N 84.16W
03/31/2022  M62 MPH          CAMPBELL           TN   AWOS

            REPORTED AT CAMPBELL COUNTY AIRPORT.

0212 AM     NON-TSTM WND DMG 1 NNE JELLICO           36.59N 84.12W
03/31/2022                   CAMPBELL           TN   PUBLIC

            WIND BLEW A PORTION OF THE ROOF OFF A HOUSE.

0200 AM     NON-TSTM WND GST 2 ENE CADES COVE        35.60N 83.78W
03/31/2022  M61 MPH          BLOUNT             TN   MESONET

            PEAK WIND FROM GSMNP WIND TOWER AT CADES
            COVE.

0136 AM     NON-TSTM WND GST TRI-CITY AIRPORT        36.48N 82.40W
03/31/2022  M45 MPH          SULLIVAN           TN   ASOS

            ASOS STATION KTRI TRI-CITIES AIRPORT.

0135 AM     NON-TSTM WND GST 3 W HARRISBURG          35.86N 83.53W
03/31/2022  M52 MPH          SEVIER             TN   AWOS

            RECORDED AT THE SEVIER COUNTY AIRPORT.

0135 AM     NON-TSTM WND GST 3 N ROCKWOOD            35.92N 84.68W
03/31/2022  M47 MPH          MORGAN             TN   AWOS

            AWOS STATION KRKW ROCKWOOD.

0110 AM     NON-TSTM WND GST 5 SW ONEIDA             36.46N 84.59W
03/31/2022  M47 MPH          SCOTT              TN   AWOS

            MESONET STATION KSCX SCOTT MUNICIPAL
            AIRPORT.

1255 AM     NON-TSTM WND GST 2 N CADES COVE          35.62N 83.81W
03/31/2022  M46 MPH          BLOUNT             TN   MESONET

            MESONET STATION IGGT1 INDIAN GRAVE GAP (2 N
            CADES COVE).

1235 AM     NON-TSTM WND GST 2 SW ANDREWS            35.18N 83.85W
03/31/2022  M45 MPH          CHEROKEE           NC   AWOS

            AWOS STATION KRHP ANDREWS NC.

1140 PM     NON-TSTM WND GST 1 SSW HUNTER            36.37N 82.17W
03/30/2022  M46 MPH          CARTER             TN   AWOS

            AWOS STATION K0A9 ELIZABETHTON.

1135 PM     NON-TSTM WND DMG 3 WSW ANDREWS           35.18N 83.87W
03/30/2022                   CHEROKEE           NC   TRAINED SPOTTER

            REPORTED BY TRAINED SPOTTER. STEEL
            OUTBUILDING BLOWN OVER AND DOWN A HILL. NO
            INJURIES REPORTED. REPORT VIA AMATEUR RADIO
            OPERATOR KO4SBR.

1115 PM     NON-TSTM WND GST 4 SE CHATTANOOGA        35.03N 85.20W
03/30/2022  M47 MPH          HAMILTON           TN   ASOS

            ASOS STATION KCHA CHATTANOOGA AIRPORT.

1115 PM     NON-TSTM WND GST 1 NE TASSO              35.22N 84.80W
03/30/2022  M45 MPH          BRADLEY            TN   AWOS

            AWOS STATION KRZR CLEVELAND.

0600 PM     NON-TSTM WND GST 2 NNE HAPPY VALLEY      35.64N 83.94W
03/30/2022  M77 MPH          BLOUNT             TN   MESONET

            PEAK WIND FROM GSMNP WIND TOWER AT LOOK
            ROCK.

Environment

A strong upper trough moved across the midsection of the nation into the Ohio and Tennessee Valleys from Wednesday into Thursday morning. The strongest part of the upper jet was over the Mississippi Valley into the western sections of the Ohio and Tennessee Valleys where 300mb winds exceeded 140 knots. Strong forcing from this occurred across the Gulf Coast states and Tennessee Valley.

The deep and strong upper forcing produced rapid surface cyclogenesis over the Great Lake states. The strong pressure falls tightened the pressure gradient across the Ohio and Tennessee Valley, and southern Appalachians with 850mb low-level jet increasing to 75 kts.


Figure 1: 300mb Heights, Divergence, and Winds at 0500 UTC, 31 March 2022	Figure 2: 500mb Heights and Winds (color shaded) at 0500 UTC, 31 March 2022	Figure 3: 850mb Heights and Winds at 0500 UTC, 31 March 2022

The strong low-level jet of 75kts+ produced downsloping winds across the southern Appalachian Mountains. The anomalously strong low-level 850mb jet, combined with the tight pressure gradient over the area, produced a high-end Mountain Wave event across the far East Tennessee Mountains and Foothills.

The strong upper-level forcing helped induce strong surface cyclogenesis across the western Great Lakes into the Ohio and Tennessee Valleys. The tightening of the surface pressure gradient is evident across East Tennessee, especially in the mountains of the southern Appalachians.

The air mass across much of the southern Appalachians, especially East Tennessee, was quite dry with dew points in the 30s and 40s which produced relative humidity values in the 20s to lower 30s. The downslope compressional warming off the far east Tennessee Mountains intensified the dry and warm boundary layer environment.


Figure 4: 850mb Heights and Winds at 0500 UTC, 31 March 2022	Figure 5: Surface MSL Pressure and surface wind at 0500 UTC, 31 March 2022	Figure 6: Surface Dew Point (F), isobars, and wind at 0400 UTC, 31 March 2022

A warm, dry downslope wind is called a Foehn. Foehn wind onset can be accompanied by a very rapid temperature increase at the surface. The strong southerly winds rise over the higher elevations of the southern Appalachians. As the air rises, the moisture is squeezed out of the parcel of air, which leaves it very dry as it descends off the far East Tennessee Mountains into the Foothills. This dry air then sinks down the lee side of the mountains and warms adiabatically. The dry and warm air mass increases wildfire risk, and the very high wind speeds spread flames quickly across the landscape.


Figure 7: University of Alabama, Huntsville, AL sounding at 2100 UTC, 30 March 2022.	Figure 8: Terrain Map of the Southern Appalachians with Arrows Showing Southerly Winds Riding Up and Over the Mountains	Figure 9: Downslope Winds Infographic: Producing Warm, Dry, Gusty Winds on the Leeward Slopes of Mountains, Enhancing Fire Danger