2011-04-15 DISC: MS/AL

[Brandon Lawson]

I'm surprised no one has started a discussion thread about this day. 94 tornado reports, mostly concentrated over Mississippi and Alabama, but some as far north as Illinois and even Missouri; some of these tornadoes were significant tornadoes. 149 hail reports and 119 wind reports. A strong low-pressure center, responsible for sustained winds above 45 mph across areas of Colorado, Kansas, Oklahoma, and Texas, wreaked havoc over much of Mississippi and Alabama. Reports: http://www.spc.noaa.gov/climo/reports/110415_rpts.html

I was curious as to whether or not the SPC has changed their criteria for what warrants a high risk. Even without a high risk, not a single PDS watch was issued today. This is a touchy subject and has sparked heated discussions in the past; so I don't really want to start a huge fire. But on a day like today, it does cross one's mind. It was a fantastic day from a meteorological perspective nonetheless.

Impressive Water Vapor Imagery with eye feature (shamelessly taken from Facebook):

You can see warm moist air from the gulf being pulled all the way around the low-pressure center into the Dakotas and Nebraska, creating a nice temperature gradient over the Plains; and the resulting mid-level jet dipping from North Dakota, down through Oklahoma and Arkansas, back around the base of the low-pressure center.

 

[Bill Walker]

Agree on yesterday (4/15) & the lack of PDS but yet, today, the Carolinas HAVE been given a PDS w/ the same system. I wonder what the difference is in SPC's thinking between yesterday & today, criteria/justification-wise?

 

[mikegeukes]

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE JACKSON MS
732 PM CDT SAT APR 16 2011

..PRELIMINARY STORM SURVEY INFORMATION

COUNTY: HINDS
http://kamala.cod.edu/offs/KJAN/1104170032.nous44.html

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE JACKSON MS
705 PM CST SAT APR 16 2011

..UPDATED STORM SURVEY REPORTS

NESHOBA/KEMPER COUNTY TORNADO
http://kamala.cod.edu/offs/KJAN/1104170005.nous44.html

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE JACKSON MS
605 PM CST SAT APR 16 2011

..UPDATED STORM SURVEY REPORTS
ATTALA COUNTY TORNADO

http://kamala.cod.edu/offs/KJAN/1104162307.nous44.html

Mike

 

[Bart_Comstock]

Agree on yesterday (4/15) & the lack of PDS but yet, today, the Carolinas HAVE been given a PDS w/ the same system. I wonder what the difference is in SPC's thinking between yesterday & today, criteria/justification-wise?

On top of this the SPC decided to issue a HIGH risk for today as well. I fail to see why the SPC was less concerned yesterday than they were today and am curious as to here what the reasoning for this was.

 

[rdale]

I have a quick guess... The SPC is made up of individual forecasters

The met who issued today's high was not issuing the DY1 for the last two days. It's good to learn their names as it enables you to "tweak" the forecasts/watches based on who issues them. Around this part of the country, it doesn't take long to learn which ones get too excited about overnight sevwx, or marginal tornado threat, and "fine tune" the outlook or the watch box probabilities downward.

 

[Christopher E. Kincaid]

Mods: Please add IL to the title

Here are the NWS survey reports of the tornadoes in Cent IL, including the one I caught:

...DAMAGE SURVEY CONDUCTED IN MASON COUNTY AND MENARD COUNTY FOR
APRIL 15TH TORNADOES...

THE FOLLOWING IS PRELIMINARY INFORMATION FROM A DAMAGE SURVEY
CONDUCTED BY THE NWS LINCOLN OFFICE IN MASON COUNTY AND MENARD
COUNTY FOR TORNADOES WHICH OCCURRED DURING THE EVENING OF FRIDAY
APRIL 15TH.

..MASON COUNTY (This the tor I chased)

NARRATIVE...A TORNADO DEVELOPED AT 530 PM CDT 6.5 MILES WEST-SOUTHWEST
OF EASTON. THE TORNADO KNOCKED OVER THREE SECTIONS OF AN IRRIGATION UNIT AND DAMAGED THE DOORS OF AN OUTBUILDING. THE TORNADO TRAVELED TO THE NORTH AND DAMAGED ANOTHER OUTBUILDING...SEVERAL TREES AND TORE SHINGLES OFF OF A HOUSE ROOF. THE TORNADO INCREASED IN INTENSITY AS IT CONTINUED TO TRAVEL TO THE NORTH. IT PUSHED A HOUSE A FEW INCHES OFF ITS FOUNDATION...BROKE WINDOWS...TORE OFF ROOFING AND SIDING...COLLAPSED A GARAGE...AND DAMAGED THREE SHEDS AND FOUR AUTOMOBILES. ONE PERSON WAS INJURED IN THE HOUSE WHEN THEY WERE CUT BY BROKEN WINDOW GLASS. THE TORNADO THEN DAMAGED ANOTHER LARGE OUTBUILDING AND SEVERAL TREES BEFORE DISSIPATING 7 MILES WEST-NORTHWEST OF EASTON AROUND 538 PM CDT.

ABOUT 1.5 MILES TO THE NORTHWEST OF WHERE THE TORNADO DISSIPATED...DOWNDRAFT WINDS DAMAGED A DOZEN IRRIGATION
UNITS AND DOWNED NUMEROUS SMALL TREE LIMBS.

BEGINNING: 530 PM CDT...6.5 MILES WEST-SOUTHWEST OF EASTON
ENDING: 538 PM CDT...7 MILES WEST-NORTHWEST OF EASTON
PATH LENGTH:3.2 MILES
MAXIMUM WIDTH: 100 YARDS
ESTIMATED MAX WIND: 90-100 MPH
EF SCALE RATING: EF1


..MENARD COUNTY - 1ST TORNADO

NARRATIVE...ATHENS FIRE PERSONNEL WITNESSED A TORNADO DEVELOPING
AROUND 622 PM ABOUT ONE MILE NORTHEAST OF ATHENS. THE TORNADO
TRACKED TO THE NORTH-NORTHWEST DAMAGING A WINDOW...SIDING AND
GUTTERS ON A HOUSE. LAW ENFORCEMENT PERSONNEL WITNESSED THE
TORNADO ABOUT 2 MILES NORTH-NORTHEAST OF ATHENS BEFORE IT
DISSIPATED AROUND 624 PM.

BEGINNING: 622 PM CDT...1 MILE NORTHEAST OF ATHENS
ENDING: 624 PM CDT...2 MILES NORTH-NORTHEAST OF ATHENS
PATH LENGTH: 1.2 MILES
MAXIMUM WIDTH: 50 YARDS
ESTIMATED MAX WIND: 70 MPH
EF SCALE RATING: EF0


..MENARD COUNTY - 2ND TORNADO

NARRATIVE...A SECOND TORNADO DEVELOPED IN AN OPEN FIELD ABOUT 3 MILES
NORTHEAST OF ATHENS AT 625 PM CDT...ABOUT 1.4 MILES EAST-NORTHEAST
OF WHERE THE FIRST TORNADO DISSIPATED. THE TORNADO TRACKED ALMOST
DUE NORTH...AND DID EXTENSIVE DAMAGE TO A HOUSE ROOF...DESTROYING A
SMALL GARAGE...AND DOING DAMAGE TO ANOTHER LARGER GARAGE AND
SEVERAL AUTOMOBILES. THE TORNADO THEN DAMAGED A SHED AND SEVERAL
TREES. FARTHER TO THE NORTH...THE TORNADO KNOCKED TWO TREES DOWN ONTO
A HOUSE...DOING SEVERE DAMAGE TO THE HOUSE ROOF AND INTERIOR WALLS
OF THE HOUSE...ALONG WITH DAMAGE TO THREE VEHICLES AND A SHED. THE
TORNADO BEGAN TO WEAKEN...BUT AS IT TURNED A BIT TO THE NORTH-
NORTHWEST IT STILL DID SHINGLE DAMAGE TO A HOUSE ROOF...KNOCKED
DOWN A SHED WALL AND TIPPED OVER A SEMI-TRAILER. THE TORNADO THEN
DAMAGED SEVERAL TREES BEFORE DISSIPATING AROUND 631 PM ABOUT
4.8 MILES NORTH-NORTHEAST OF ATHENS.

ANOTHER FUNNEL CLOUD WAS SIGHTED ABOUT ONE MILE TO THE NORTHEAST
OF THE WHERE THE TORNADO DISSIPATED...BUT IT DID NOT PRODUCE ANOTHER
TORNADO. INSTEAD DOWNDRAFT WINDS OF 70 TO 80 MPH DID MINOR ROOF
DAMAGE TO A HOUSE...A LEAN-TO SHED...AND SEVERAL TREES AT THE
SUGAR GROVE CEMETERY.

BEGINNING: 625 PM CDT...3 MILES NORTHEAST OF ATHENS
ENDING: 631 PM CDT...4.8 MILES NORTH-NORTHEAST OF ATHENS
PATH LENGTH: 2.3 MILES
MAXIMUM WIDTH: 150 YARDS
ESTIMATED MAX WIND: 95-105 MPH
EF SCALE RATING: EF1