2020 Mid-Atlantic Severe Weather - General Thread

[Kmlwx]

It's only January...but with the winter season looking incredibly bleak...let's fire up the 2020 Mid-Atlantic Severe Disco Thread. 

May our lack of winter weather this season forebode a spring and summer FULL of the folllowing

@yoda copying and pasting

@Eskimo Joe being bullish on events

@mappy getting to break out some GIS skills on something local

@Ian popping in to tell us the upcoming pattern looks ripe

@high risk with ample opportunity to educate us and keep our hopes high when it looks like we won't get sun before an event. 

As a reminder - the Mid-Atlantic Severe Weather Reference Scale is displayed below - @WxWatcher007 to credit for this. 

Let's shoot for a moderate risk in 2020. 

 

[Eskimo Joe]

From a climo perspective we are due for a derecho.

[Kmlwx]

22 minutes ago, Eskimo Joe said:

From a climo perspective we are due for a derecho.

This is an excellent start to the thread. My only issue with derecho patterns is that they can be very hot ones...worth it for excitement I guess. 

[Stormfly]

I'll take the heat for it!

There's nothing like ending a HOT day with continuous lightning and roaring winds.  July 21, 2019 was such a day for us.  Most of the time here we bust bigtime with anticipated widespread severe events.  It's the ones that seemingly come out of nowhere that sneak up on you.  Those you have to watch out for!

[Vice-Regent]

Now we transition to a warm season board. That's a good way to start the decade.

[Eskimo Joe]

On 1/19/2020 at 8:52 AM, Kmlwx said:

This is an excellent start to the thread. My only issue with derecho patterns is that they can be very hot ones...worth it for excitement I guess. 

The "we are due" index is pretty high in several areas specifically:

1.) Derecho 

2.) Tropical system/remnants

3.) EF-2 or greater tornado

4.) Large scale river flooding event

 

Sooner or later the pendelum is going to swing back on us. 

[Kmlwx]

1 hour ago, Eskimo Joe said:

The "we are due" index is pretty high in several areas specifically:

1.) Derecho 

2.) Tropical system/remnants

3.) EF-2 or greater tornado

4.) Large scale river flooding event

 

Sooner or later the pendelum is going to swing back on us. 

EF-2 is exciting from a distance - but locally it's just too populated to hope for anything like that. Imagine if we pulled a prolonged ring of fire derecho pattern and then topped it off with a tropical system in the fall. Would easily make up for a dreadful winter (barring late turn around). 

[George BM]

1 hour ago, Eskimo Joe said:

The "we are due" index is pretty high in several areas specifically:

1.) Derecho 

2.) Tropical system/remnants

3.) EF-2 or greater tornado

4.) Large scale river flooding event

 

Sooner or later the pendelum is going to swing back on us. 

Maybe we get our dues all at once? 

...

 

[Eskimo Joe]

 

[Kmlwx]

I looked at the CFS supercell composite maps on the COD page last night. This winter sucks. 

[Kmlwx]

We always seem to "luck" our way into at least one severe weather "event" every February. Then we usually go mostly dormant until April or May. 

[Stormfly]

Feb 26, 2016 comes to mind...

[yoda]

2 hours ago, Kmlwx said:

We always seem to "luck" our way into at least one severe weather "event" every February. Then we usually go mostly dormant until April or May. 

Good amount of TW and STW for no watch this morning lol 

[Kmlwx]

Just now, yoda said:

Good amount of TW and STW for no watch this morning lol 

Let's do this again with 80+ degree temps and 65+ dews. 

[yoda]

2 minutes ago, Kmlwx said:

Let's do this again with 80+ degree temps and 65+ dews. 

Lots of reports from LWX too... looks like at least 30

[George BM]

@yodaI see that you're finally up. 

 

[Kmlwx]

1 hour ago, WxWatcher007 said:

First biggie of the year.

 Low CAPE, high shear events fail for us like 90 percent of the time. 

[George BM]

This is only based off of what I personally have observed in these parts. So this is in absolutely no way expert analysis.

I've noticed that the few times that we can actually do "well enough" and get close to maximizing our potential with low CAPE/high shear convective events is whenever we have a trough that tilts negative to our west with a strengthening surface low moving up the Appalachian Mountains. April 6, 2017 comes to mind. Also December 21, 2018 which probably no one remembers because the storms from this "event" only produced some brief 40-50+mph wind gusts and small hail from NVA into north/central MD and was more localized than this mornings event... but it was still at least something for late Dec and the wind profiles were weaker for that "event". This is assuming that CAD erodes quickly enough of course.

I know... this is a very small sample size I'm sure there might be a few that I didn't mention. People on here who know more than me, what's your take? 

[NorthArlington101]

Did we just have our biggest event of the year? I totally missed this one.

[Kmlwx]

20 minutes ago, NorthArlington101 said:

Did we just have our biggest event of the year? I totally missed this one.

This is only the beginning. Here's the seasonal projection from the weenie simulation - 

Rest of February - Not much but maybe some gusty showers

March - Regular bouts of severe synoptic wind following behind monster lows with squalls and wedges rapidly raking the area. 

April - Regular bouts of moist, warm air clashing with high shear events to warm us up for peak season. 

May - Daily wedges

June - Daily wedges centered on the mall. 

[yoda]

Looks like 2 EF0 and 3 EF1 tornadoes confirmed by LWX today... wow.

[yoda]

 

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
657 PM EST FRI FEB 7 2020

...EF-0 TORNADO CONFIRMED IN LEESBURG VIRGINIA FRIDAY MORNING FEB 7 2020...

LOCATION...TOWN OF LEESBURG IN LOUDOUN COUNTY VIRGINIA
DATE...FRI FEB 7 2020
ESTIMATED TIME...7:20 AM EST TO 7:23 AM EST
MAXIMUM EF-SCALE RATING...EF0
ESTIMATED MAXIMUM WIND SPEED...85 MPH
MAXIMUM PATH WIDTH...250 YARDS
PATH LENGTH...3.3 MILES
BEGINNING LAT/LON...39.0946/-77.5874 
ENDING LAT/LON...39.1291/-77.5431
* FATALITIES...0
* INJURIES...0

...SUMMARY...
STAFF FROM NOAA'S NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON WEATHER
FORECAST OFFICE LOCATED IN STERLING, VA PERFORMED A SURVEY OF 
STORM DAMAGE THAT OCCURRED IN THE TOWN OF LEESBURG, VA ON THE 
MORNING OF FEBRUARY 7, 2020. THIS SURVEY, COUPLED WITH RADAR 
ANALYSIS FROM THE KLWX WSR-88D AND THE FAA'S TIAD TERMINAL DOPPLER
WEATHER RADAR, CONCLUDED THAT A TORNADO RATED EF0 ON THE ENHANCED
FUJITA SCALE IMPACTED THE TOWN OF LEESBURG BETWEEN 7:20 AM EST 
AND 7:23 AM EST. THE TORNADO HAD A PATH LENGTH OF 3.3 MILES 
PRODUCING INTERMITTENT DAMAGE, WITH A PATH WIDTH OF UP TO 250 
YARDS. THE TORNADO WAS MOVING NORTHEAST AT APPROXIMATELY 60 MPH.

THE FIRST DAMAGE WAS REPORTED IN THE GREENWAY FARM AND LINDEN HILL
SUBDIVISION IN SW LEESBURG. HERE NUMEROUS LARGE TREE LIMBS WERE 
DOWNED ALONG WITH SEVERAL TREES COMPLETELY UPROOTED. THE DAMAGE 
WAS DETERMINED TO BE CONCENTRATED BETWEEN LAWFORD DRIVE AND 
NICKELS DRIVE IN A WOODED AREA, AND ALSO ALONG GOVERNORS DRIVE AND
COUNTRY CLUB DRIVE. TIAD RADAR WAS SHOWING A ROTATIONAL SIGNATURE
BEGINNING AT 7:20 AM IN THESE LOCATIONS. WIND GUSTS IN THIS AREA 
WERE ESTIMATED TO BE 65 MPH FROM RADAR ANALYSIS AND DAMAGE 
INDICATORS.

THE TORNADO THEN LIFTED OVER ROUTE 7, WITH JUST SOME MINOR TREE 
DAMAGE NOTED IN THE 800 BLOCK OF DAVIS COURT SE. THE HISTORIC 
DOWNTOWN PORTION OF THE TOWN OF LEESBURG, NEAR KING AND MARKET 
STREETS, WAS SPARED WITH JUST MINIMAL DAMAGE. THE ONLY NOTEWORTHY
DAMAGE THAT WAS OBSERVED WAS TREE DAMAGE ALONG MONROE STREET.

AS THE TORNADO MOVED INTO NE LEESBURG, BOTH THE RADAR AND THE 
STORM SURVEY INDICATED THAT IT BECAME MUCH STRONGER. TWO AREAS OF 
WIDESPREAD, CONCENTRATED TREE DAMAGE WERE FOUND. THE FIRST ONE 
WAS IN THE VICINITY OF LOUNSBERRY ROAD NE AND THE EXETER 
SUBDIVISION; WHICH ARE NORTH OF EDWARDS FERRY ROAD AND SOUTH OF 
BATTLEFIELD PARKWAY NE. A TOWNHOME ON GINGER SQUARE NE HAD ITS 
SIDING AND UNDERLAYMENT COMPLETELY PEELED OFF, EXPOSING IT'S ROOF
TRUSSES. MANY HOMES ALONG MARSHALL DRIVE NE ALSO HAD ROOFING 
DAMAGE, ALONG WITH TREES UPROOTED AND LARGE BRANCHES DOWNED. ONE 
HOUSE HAD LAWN FURNITURE LIFTED AND BLOWN IN THE OPPOSITE 
DIRECTION OF THE WAY THE TREES WERE FALLEN AND DEBRIS WAS 
PLASTERED ON CARS AND HOMES. DAMAGE WAS NOTED SPANNING THE 500 AND
600 BLOCKS OF MARSHALL DRIVE NE, WHICH SUPPORTS THE DAMAGE WIDTH 
ESTIMATE OF 250 YARDS.

THE OTHER AREA OF CONCENTRATED WIND DAMAGE WAS NORTH OF 
BATTLEFIELD PARKWAY NE, IN AND AROUND THE FIELDSTONE APARTMENT 
COMPLEX. HERE, FIFTEEN TO TWENTY 1.5-2.0 FOOT DIAMETER PINES WERE 
UPROOTED. OF SPECIAL NOTE WAS A LINE OF 5 LARGE PINE TREES IN THE
EASTERNMOST PORTION OF THE APARTMENT COMPLEX WHICH WERE UPROOTED 
AND WHICH FELL ONTO TWO UNOCCUPIED VEHICLES. SEVERAL OF THESE 
TREES DID FALL IN A CONVERGENT PATTERN. ADDITIONAL LARGE PINE 
TREES WERE UPROOTED ALONG THE US ROUTE 15 LEESBURG BYPASS NEAR ITS
INTERSECTION WITH BATTLEFIELD PARKWAY NE.

ANALYSIS FROM TIAD RADAR SHOWED VELOCITY MEASUREMENTS UP TO 77 
KNOTS AT APPROXIMATELY 210 FEET ABOVE GROUND LEVEL AS THE TORNADO 
WAS IN THE VICINITY OF THE FIELDSTONE APARTMENTS. TAKING INTO 
ACCOUNT SOME DECREASE IN THE WIND'S MAGNITUDE AS IT GOT CLOSER TO 
GROUND LEVEL, ALONG WITH THE DAMAGE INDICATED IN AND AROUND THE 
FIELDSTONE APARTMENTS, CORROBORATES ESTIMATED WIND GUSTS OF UP TO 
85 MPH.

THE NWS BALTIMORE/WASHINGTON WEATHER FORECAST OFFICE THANKS THE 
LOUDOUN COUNTY OFFICE OF EMERGENCY MANAGEMENT WITH PROVIDING 
INFORMATION SUPPORTING THE STORM SURVEY.

EF SCALE: THE ENHANCED FUJITA SCALE CLASSIFIES TORNADOES INTO THE
FOLLOWING CATEGORIES:

EF0.........65 TO 85 MPH
EF1.........86 TO 110 MPH
EF2.........111 TO 135 MPH
EF3.........136 TO 165 MPH
EF4.........166 TO 200 MPH
EF5.........>200 MPH

* THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO
CHANGE PENDING FINAL REVIEW OF THE EVENT AND PUBLICATION IN NWS
STORM DATA.

$$

LEE

[yoda]

 

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
925 PM EST FRI FEB 7 2020

...EF-1 TORNADO CONFIRMED IN CARROLL COUNTY MD ON FRIDAY MORNING FEB 
7 2020...

LOCATION...CARROLL COUNTY MD 
DATE...FRI FEB 7 2020 
ESTIMATED TIME...8:03 AM EST TO 8:14 AM EST 
MAXIMUM EF-SCALE RATING...EF1 
ESTIMATED MAXIMUM WIND SPEED...90 MPH
MAXIMUM PATH WIDTH...100 YARDS 
PATH LENGTH...10.3 MILES INTERMITTENT
BEGINNING LAT/LON...39.5620/-77.0310
ENDING LAT/LON...39.6610/-76.8860
* FATALITIES...0
* INJURIES...0

...SUMMARY... 

EARLY ON FRIDAY FEB 7TH, A TORNADO TOUCHED DOWN AND SKIPPED 
NORTHEAST ACROSS CENTRAL CARROLL COUNTY MD CAUSING ERRATIC DAMAGE. 
WHILE THERE WAS SCATTERED TREE DAMAGE ACROSS SOUTHWESTERN CARROLL 
COUNTY, THE FIRST NOTED DAMAGE CONSISTENT WITH A TORNADO WAS IN THE 
AVONDALE RIDGE COMMUNITY JUST WEST OF ROUTE 31 AND SOUTHWEST OF 
WESTMINSTER. CLUSTERS OF SNAPPED AND UPROOTED TREES WERE NOTED. FROM 
THERE THE TORNADO CAUSED INTERMITTENT DAMAGE AS IT TRAVELED 
NORTHEAST THROUGH DOWNTOWN WESTMINSTER, ROUGHLY PARALLELING RIDGE 
ROAD AND UNION STREET. TREES WERE UPROOTED AND SNAPPED, SOME ONTO 
CARS, ROADS, AND HOMES. ADDITIONALLY, ROOFING WAS BLOWN OFF, AND 
SHINGLE AND SIDING DAMAGE WAS NOTED FROM THE WIND. THE TORNADO 
CONTINUED UP HAHN RD AND INTO THE COMMUNITY ALONG SUNSHINE WAY, 
WHERE MORE SNAPPED AND UPROOTED TREES WERE NOTED, AS WELL AS 
RESIDENTIAL FENCING DAMAGE. A LARGE RECREATIONAL VEHICLE WAS BLOWN 
OVER. ON ADJACENT PROPERTY, THE NATIONAL GUARD RECRUITING OFFICE HAD 
TREE DAMAGE.  ADDITIONALLY, A SMALL MILITARY TRAILER WAS BLOWN OVER. 
THE LAST KNOWN DAMAGE FROM THIS SEGMENT OF THE TORNADO WAS ALONG 
LUCABAUGH MILL RD, ABOUT 250 YARDS WEST OF ROUTE 27/MANCHESTER RD. 
MOST OF THE TREES ALONG THIS AREA WERE HEAVILY DAMAGED OR DOWNED. IN 
ADDITION TO GROUND SURVEYING, THERE WAS AN EYEWITNESS REPORT, AS 
WELL AS A VIDEO OF A SMALL TORNADO POSTED TO SOCIAL MEDIA, BOTH IN 
THE WESTMINSTER AREA. PEAK ESTIMATED WINDS WERE 90 MPH BASED ON THE 
MOST HEAVILY DAMAGED AREAS.

THE TORNADO LIFTED NORTHEAST OF WESTMINSTER, AND NO DAMAGE WAS NOTED 
FOR ABOUT 4 MILES UNTIL IT NEARED MANCHESTER MD. SUBSTANTIAL TREE 
DAMAGE, WITH NUMEROUS LARGE TREES UPROOTED AND SNAPPED WERE NOTED 
ALONG FORT SCHOOLHOUSE RD, FROM ALBERT RILL ROAD, TO THE NORTHEAST 
ABOUT 400 YARDS. A HOME HAD A SECTION CRUSHED BY A LARGE FALLING 
TREE. AS THE TORNADO TRAVELED NORTHEAST ALONG PARK AVENUE, TREE 
DAMAGE BECAME MORE SCATTERED, AND NO TORNADIC DAMAGE WAS NOTED 
NORTHEAST OF MD ROUTE 30 IN MANCHESTER.

THANKS TO CARROLL COUNTY MD OFFICE OF EMERGENCY MANAGEMENT FOR 
THEIR SUPPORT OF OUR STORM SURVEY.

EF SCALE: THE ENHANCED FUJITA SCALE CLASSIFIES TORNADOES INTO THE
FOLLOWING CATEGORIES:

EF0.........65 TO 85 MPH
EF1.........86 TO 110 MPH
EF2.........111 TO 135 MPH
EF3.........136 TO 165 MPH
EF4.........166 TO 200 MPH
EF5.........>200 MPH

* THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO
CHANGE PENDING FINAL REVIEW OF THE EVENT AND PUBLICATION IN NWS
STORM DATA.

$$

STRONG/LEE

[yoda]

 

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
929 PM EST FRI FEB 7 2020

...2 TORNADOES CONFIRMED IN MONTGOMERY COUNTY MD FRIDAY MORNING FEB 7 2020...

.EF1 TORNADO CONFIRMED NEAR DICKERSON MD...

LOCATION...DICKERSON IN WESTERN MONTGOMERY COUNTY MD
DATE...FRI FEB 7, 2020
ESTIMATED TIME...7:28 AM TO 7:29 AM EST
MAXIMUM EF-SCALE RATING...EF1
ESTIMATED MAXIMUM WIND SPEED...95 MPH
MAXIMUM PATH WIDTH...150 YARDS
PATH LENGTH...1.0 MILE
BEGINNING LAT/LON...39.1763/-77.4827
ENDING LAT/LON...39.1819/-77.4633
* FATALITIES...0
* INJURIES...0

...SUMMARY...
STAFF FROM NOAA'S NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON 
WEATHER FORECAST OFFICE LOCATED IN STERLING, VA PERFORMED A SURVEY
OF STORM DAMAGE THAT OCCURRED IN WESTERN MONTGOMERY COUNTY MD 
NEAR DICKERSON. THIS SURVEY, COUPLED WITH RADAR ANALYSIS FROM THE 
KLWX WSR-88D RADAR AND AN FAA TERMINAL DOPPLER WEATHER RADAR 
(TIAD), CONCLUDED THAT A TORNADO RATED EF1 ON THE ENHANCED FUJITA 
SCALE IMPACTED PORTIONS OF EXTREME WESTERN MONTGOMERY COUNTY MD 
NEAR DICKERSON.

INITIAL DAMAGE WAS NOTED IN TREES JUST WEST OF A FARM NEAR THE
POTOMAC RIVER OFF MARTINSBURG ROAD. A LARGE BARN USED TO HOUSE 
HORSES LOST ALL OF ITS ROOF WHILE AN ADJACENT OPEN-AIR POLE BARN 
WAS FLATTENED. SEVERAL SMALL OUTBUILDINGS WERE DESTROYED. 
BLEACHERS AT A HORSE SHOWING FACILITY WERE OVERTURNED. A METAL 
FRAME WINDMILL TOWER WAS TOPPLED. NUMEROUS TREES, BOTH HARDWOOD 
AND SOFTWOOD, WERE EITHER UPROOTED OR SNAPPED. THEN THE TORNADO
MOVED NORTHEAST ACROSS OPEN FIELDS. IT THEN CROSSED MARTINSBURG 
RD NEAR A FARMHOUSE WHERE SEVERAL LARGE TREES WERE UPROOTED AND A
FARMHOUSE LOST MANY SHINGLES. NO DAMAGE WAS NOTED PAST THE FARM 
HOUSE.

THIS TORNADO WAS NOT THE SAME ONE THAT STRUCK NEAR LEESBURG, VA
EARLIER. RATHER IT WAS A SHORT-LIVED TORNADO THAT SPUN UP QUICKLY
TO THE NORTHEAST OF THE CIRCULATION THAT SPAWNED THE LEESBURG, VA
EF0 TORNADO.

 

..EF0 TORNADO CONFIRMED NEAR BOYDS MD......

LOCATION...BOYDS IN MONTGOMERY COUNTY MD
DATE...FRI FEB 7, 2020
ESTIMATED TIME...7:28 AM TO 7:29 AM EST
MAXIMUM EF-SCALE RATING...EF0
ESTIMATED MAXIMUM WIND SPEED...80 MPH
MAXIMUM PATH WIDTH...75 YARDS
PATH LENGTH...2.3 MILES
BEGINNING LAT/LON...39.1301/-77.3464
ENDING LAT/LON...39.1431/-77.3113
* FATALITIES...0
* INJURIES...0

...SUMMARY...
STAFF FROM NOAA'S NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON 
WEATHER FORECAST OFFICE LOCATED IN STERLING, VA PERFORMED A SURVEY
OF STORM DAMAGE THAT OCCURRED IN WEST-CENTRAL MONTGOMERY COUNTY 
MD NEAR BOYDS. THIS SURVEY, COUPLED WITH RADAR ANALYSIS FROM THE 
KLWX WSR-88D RADAR AND AN FAA TERMINAL DOPPLER WEATHER RADAR 
(TIAD), CONCLUDED THAT A TORNADO RATED EF0 ON THE ENHANCED FUJITA 
SCALE IMPACTED PORTIONS OF WEST-CENTRAL MONTGOMERY COUNTY MD NEAR 
BOYDS AND DAWSONVILLE.

INITIAL DAMAGE WAS NOTED ON DARNESTOWN ROAD (RT 28) BETWEEN WHITE
GROUND RD AND SUGARLAND RD WHERE SEVERAL SOFTWOOD TREES WERE 
TOPPED AND FELL ACROSS UTILITY LINES ON DARNESTOWN RD.

AFTER PASSING OVER LARGELY RURAL FIELDS AND WOODLANDS THE TORNADO
DAMAGED SEVERAL STRUCTURES AT A DOG TRAINING FACILITY IN THE 
14000 BLOCK OF SCHAEFFER ROAD. HERE AN OPEN FACING STORAGE 
OUTBUILDING WAS FLATTENED. ROOFING MATERIAL CARRIED FROM THE 
DESTROYED OUTBUILDING DAMAGED TWO OTHER OFFICE TRAILER STRUCTURES.
A 10 FOOT 2X4 IMPALED THE SIDE OF ONE OF THE OFFICE TRAILERS 
WHILE ANOTHER 2X4 IMPALED THE ROOF OF THE SECOND OFFICE TRAILER. 
SOME TREE DAMAGE WAS NOTED JUST TO THE NORTHEAST OF THIS FACILITY 
BUT ALL DAMAGE ENDED SHORTLY THEREAFTER.

EF SCALE: THE ENHANCED FUJITA SCALE CLASSIFIES TORNADOES INTO THE
FOLLOWING CATEGORIES:

EF0.........65 TO 85 MPH
EF1.........86 TO 110 MPH
EF2.........111 TO 135 MPH
EF3.........136 TO 165 MPH
EF4.........166 TO 200 MPH
EF5.........>200 MPH

* THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO
CHANGE PENDING FINAL REVIEW OF THE EVENTS AND PUBLICATION IN NWS
STORM DATA. THE NATIONAL WEATHER SERVICE THANKS MONTGOMERY COUNTY
EMERGENCY MANAGEMENT FOR THEIR ASSISTANCE IN CONDUCTING THESE SURVEYS.

$$

SMZ/KJP

[yoda]

 

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1031 PM EST FRI FEB 7 2020

...EF1 TORNADO CONFIRMED IN FREDERICK COUNTY MD FRIDAY MORNING FEB 7 2020...

LOCATION...MONROVIA IN FREDERICK COUNTY MD
DATE...FRI FEB 7, 2020
ESTIMATED TIME...7:44 AM TO 7:50 AM EST
MAXIMUM EF-SCALE RATING...EF1
ESTIMATED MAXIMUM WIND SPEED...105 MPH
MAXIMUM PATH WIDTH...150 YARDS
PATH LENGTH...6.0 MILES
BEGINNING LAT/LON...39.3427/-77.2758
ENDING LAT/LON...39.4155/-77.1917
* FATALITIES...0
* INJURIES...0

...SUMMARY...
STAFF FROM NOAA'S NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON 
WEATHER FORECAST OFFICE LOCATED IN STERLING, VA PERFORMED A SURVEY
OF STORM DAMAGE THAT OCCURRED IN EASTERN FREDERICK COUNTY MD NEAR
MONROVIA AND NEW MARKET. THIS SURVEY, COUPLED WITH RADAR ANALYSIS
FROM THE KLWX WSR-88D RADAR AND AN FAA TERMINAL DOPPLER WEATHER 
RADAR (TIAD), CONCLUDED THAT A TORNADO RATED EF1 ON THE ENHANCED 
FUJITA SCALE IMPACTED PORTIONS OF EASTERN FREDERICK COUNTY MD.

INITIAL DAMAGE WAS TO SEVERAL STRUCTURES AT A FARM IN THE 11000 
BLOCK OF FINGERBOARD ROAD, WHERE A MACHINE SHED AND BARN WERE 
FLATTENED. A SILO WAS ALSO HEAVILY DAMAGED. TREE DAMAGE WAS NOTED 
NEAR THE INTERSECTION OF STATE ROUTES 75 AND 80. A LARGE SWATH OF 
TREE AND UTILITY LINE DAMAGE WAS NOTED ALONG LYNN BURKE RD NEAR 
OLD BARTHOLOWS RD JUST SOUTH OF I-70.

THE TORNADO CROSSED I-70 AND MOVED ALONG JESSE SMITH RD WHERE
MORE TREE DAMAGE (UPROOTED AND TOPPED) WAS OBSERVED. FURTHER 
NORTH ALONG THE 12900 BLOCK OF JESSE SMITH RD, MORE SIGNIFICANT 
TREE DAMAGE OCCURRED WITH NUMEROUS SOFTWOOD TREES TOPPED AT TWO 
RESIDENCES ALONG A CONCENTRATED DAMAGE PATH. 

THE TORNADO CONTINUED NORTHEAST OVER OPEN COUNTRY BEFORE CROSSING
OLD ANNAPOLIS RD NEAR RAVENWOOD RD, PRODUCING EXTENSIVE TREE 
DAMAGE AT SEVERAL RESIDENCES. FINALLY, THE TORNADO CAUSED TREE 
DAMAGE AS IT CROSSED BOTTOM RD ALONG WOODVILLE BRANCH AND 
CONTINUED INTO A WOODED AREA THAT WAS NOT SURVEYED DUE TO 
IMPENDING DARKNESS.

EF SCALE: THE ENHANCED FUJITA SCALE CLASSIFIES TORNADOES INTO THE
FOLLOWING CATEGORIES:

EF0.........65 TO 85 MPH
EF1.........86 TO 110 MPH
EF2.........111 TO 135 MPH
EF3.........136 TO 165 MPH
EF4.........166 TO 200 MPH
EF5.........>200 MPH

* THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO
CHANGE PENDING FINAL REVIEW OF THE EVENT AND PUBLICATION IN NWS
STORM DATA. THE NATIONAL WEATHER SERVICE THANKS FREDERICK COUNTY MD
EMERGENCY MANAGEMENT FOR THEIR ASSISTANCE IN CONDUCTING THESE SURVEYS.

$$

SMZ/KJP

[Maestrobjwa]

4 tornados...in one February day. Wow! (can't believe I'm posting in a severe thread in February, lol) Now...shall the old folklore about thunder and snow ring true this time? Stay tuned! 

[Kmlwx]

8 hours ago, Maestrobjwa said:

4 tornados...in one February day. Wow! (can't believe I'm posting in a severe thread in February, lol) Now...shall the old folklore about thunder and snow ring true this time? Stay tuned! 

And in the morning no less. Very, very impressive event even by normal severe season standards. 

[Maestrobjwa]

17 minutes ago, Kmlwx said:

And in the morning no less. Very, very impressive event even by normal severe season standards. 

Yes seriously...I don't ever remember waking up to a morning thunderstorm in February (doesn't seem like we get them a lot in the morning even in the summertime!). Of course the weenie in me says "hey, maybe it re-shuffled the winter pattern!"...lol Either way, this was a bit anomalous, wasn't it?

[csnavywx]

Normally with that much shear and low cape, updrafts are simply tilted and sheared out of existence before they can do much. Yesterday was different. The total amount of cape was low (~500J/kg), but it was very low topped (around 450-500mb top, around -20 to -25C, just cold enough for charge separation and lightning) and concentrated. A more "normal" sounding with a higher top would've resulted in values 2-3x that large. That didn't matter in this case. The amount of instability was concentrated vertically and parcel acceleration was large enough to balance the shear somewhat and thus these shallower, but stronger updrafts could tap into the extremely high ambient helicity.

[csnavywx]

Incidentally, this isn't the first setup like that this year. The one in January that produced a forced line of low-topped showers had a somewhat similar evolution (CAA and dry slotting aloft with some surface heating). It lacked the more beefy mid-level CAPE or it would have produced a similar result wrt wind damage.