Radar Analysis on mULLICA hILL, NJ

History

Conditions

Radar

Event Description

Conclusion

Main Analysis

Overview of Essential Radar products

Analysis below

Note: All Small red boxes in the middle of each radar product signifies the location of Mullica Hill, with the exception of the convective initiation section.

Base Reflectivity Base Velocity

Correlation Coefficient (CC) Differential Reflectivity (ZDR)

The GR2 4 panel display above shows a loop as the supercell originated in Southwestern Delaware, then crossing the Chesapeake Bay into New Jersey, and continuing up and through Mullica Hill, New Jersey.

Base Reflectivity

This Product is used for measuring the intensity of Targets, measured in dBZ, BY RECEIVING THE AMOUNT OF TRANSMITTED POWER FROm THE TARGET. This has the ability to pick up on heavy Precipitation, hail cores, and heavy debris. Base PRODUCTS can be Adjusted at Various angles, ranging from 0.5° to 19.5°. This specific imagery is adjusted TO a 0.5° TILT .

Base Velocity

This Product is used for observing the velocity measured by the radar, relative to the actual wind speed. THe radar can pick up actual wind speeds as long as the winds are parallel to the Radar beam (or the radial), as it looks for changes along the beam. If the winds are perpendicular to the radar beam, There won't be any changes along the radial, therefore it will read very little to no windspeeds. This line of low wind speeds along the radial is known as the zero isodop.

cORRELATION COEFFICIENT (CC)

This Product is used for measuring the size distribution in the hydrometeors (rain drops vs other types of targets) present in an event. When looking at the CC, The warmer red and purple colors (High CC values) resemble meteorological targets, whereas cooler colors (A drop in CC values) resemble non-meteorological targets. In a convective event, A drop in CC can be indicative of a tornado, as Debris is being lofted into the air and observed by the radar beam.

Spectrum Width (sw)

This Product is used for measuring the flow of an air parcel. typically lower values depict smooth flow (such as the rear flank downdraft), whereas higher values depict turbulent and chaotic flow (such as tornadoes). High values on their own are not indicative of tornadoes, but when used in conjunction with other radar products we can determine if a tornado is present.

DIFFERENTIAL REFLECTIVITY (zDR)

This Product analyzes the horizontal and vertically polarized beams on a logarithmic axis. Positive values indicate hydrometeors are larger in the horizontal whereas negative values are larger in the vertical. Differential reflectivity can identify hail shafts the raindrop size and identify aggregation of dry snow.

SPECIFIC DIFFERENTIAL PHASE (KDP)

This Product HELPS THE user to identify key changes in size and concentration of precipitation. since kdp helps in identifying those changes, we can then locate and pinpoint exactly where there ARE increasing rainfalL rates.

Convective Initiation of mullica hill supercell

This is an overview of the chase area. The current tornado warning issued in this frame (4 pm) is from the Rising Sun MD through Oxford PA tornado. The small red box in the center of the image indicates the convective initiation of the Mullica Hill tornado.

(Zoomed-in image of the previous aerial image) The western part of the Cambridge cell (where the red square is in the center) starts to split from its current cell to merge with the cell in Easton MD. (still 4 pm)

After the Cambridge cell merged with the cell in Easton MD, we can see a new cell structure starting to take place. As the cell develops, we can see the area where the inflow notch will take place. The first tornado warning for this cell was issued when it crossed into Delaware. (4:15 pm)

rapid intensification of the supercell

Once the first warning was issued for the cell, rapid intensification begins. A more predominant updraft begins forming and cloud tops begin to significantly grow compared to when the cell had first been warned. The first warned cell on the bottom left had a cloud top height of 22.3 kft, whereas the last warned cell in Delaware, on the bottom right, had a cloud top height of 28.2 kft. This imagery shows the updraft rapidly intensifying, and in turn caused overshooting cloud tops, increasing by 6 kft, in as little as thirty minutes.

This shows the Echo Tops of the cell when it first got warned west of Dover DE. (5 pm)

This shows the Echo Tops of the cell right as it enters the Chesapeake Bay (5:30 pm)

WHEN THE Tornado hits mullica hill

Gr2 Quad pane image at 5:49 pm

Once the storm crossed the Chesapeake Bay into New Jersey, it not only continues to intensify, it could have a tornado. Radar is indicative of rapid rotation, with turbulent flow. Correlation Coefficient has lower values in the Mesocyclone, however according to CC there is nothing yet indicating debris being lofted in the air.

Gr2 Quad pane image at 6:19 pm

This is the frame before it hits mullica hill, with a well defined hook, CC DRop and high sw values underneath the couplet.

hERE IS A CROSS-SECTION graphic image file (GIF) OF THE supercell the frame prior to it directly hitting mullica hill. You can see a well defined mesocyclone in the lower portion, along with a well defined rotating updraft shooting well over 50kft. (cross-section during the 6:19 radar scan from above)

hERE IS still A 3-Dimensional CROSS-SECTION OF THE rotating updraft from the same reference frame. It is easier to see the updraft and wind characteristics in the cloud structure. We'll get to Echo tops later, however, the updraft splitting into 2 directions, in this case, helps the cloud tops shoot to their highest recorded height of the supercell. (cross-section during the 6:19 radar scan from above)

Gr2 Quad pane image at 6:21 pm

2 minutes later, directly over mullica hill, with a radar estimated 170 MPH Wind speed. (Later determined Ef-3)

Gr2 Quad pane image at 6:21 pm

A zoomed in look at the tornado directly hitting mullica hill. each explained radar product indicates a large pds tornado.

This is A cross-sectional look at the Tornado hitting mullica hill on Correlation Coefficient. Image at 6:21 pm

In this cross-sectional look at the TOrnado, we see a massive debris signature with debris being lofted well over 20kft.

Gr2 Quad pane image at 6:23 pm

This is the frame 2 minutes after it went through Mullica Hill. The supercell was moving extremely fast, with a large wedge tornado.

3-dimensional view of the back end of the supercell, specifically looking at the radar-produced mesocyclone. Looking through the lens of Base reflectivity, this gives the 3d cross-section more of a cloud look. If you look carefully you can see high reflectivity values within the mesocyclone, showing a large amount of debris being lofted not only into the mesocyclone circulation but into the updraft as well.

Here's a clear indication of a Differential Reflectivity (ZDR) ring out surrounding the tornado on the leading edge of the inflow. Supercell Thunderstorms often have these pronounced signatures of large horizontal hydrometeors (given the large positive values just north of Mullica Hill), with an arc or ring shape of higher values of ZDR. These arc signatures are typically found within the Foward Flank regions, however, it isn't uncommon to see one develop in the rear flank as well. See Differential Reflectivity (ZDR) in the overview of essential radar products to see a moving image of the example above.

Comparing the same echo tops from previously, when initially warned the tops were at 22.3 kft with it rising to 28.2 kft before hitting the Chesapeake bay. When the supercell was over mullica hill the echo tops were at 53.4 kft. that is a 25 kft increase from the start of NJ and a 31 kft increase from the first warning.

Looking at the Specific differential phase (KDP) in the top left of the quad pane view, there is very little precipitation when the tornado is over Mullica hill. in fact most of the precipitation is to the north and west of the tornado. This is indicative of an lp (low precipitation) supercell, compared to the numerous other hp's (High precipitation) throughout the day.

Event Description

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