Probability of any form of severe weather within 25 miles of a point between 8 a.m. tomorrow and 8 a.m. Thursday. Source: updated SPC “Day 2 Convective Outlook” issued at 1:18 p.m. EDT
No part of the country has a severe weather probability of greater than 30 percent, according to an updated “Day 2 Convective Outlook” that the National Weather Service Storm Prediction Center issued at 1:18 p.m. EDT. The entire state of Indiana and all 37 counties in the county warning area of the northern Indiana NWS office continue to have a slight risk of servere weather between 8 a.m. EDT tomorrow and 8 a.m. EDT Thursdsay, with probabilities ranging form 15 to 30 times higher than a normal day for this time of year.
At midday, forecast models indicated a weaker low pressure system than previously expected. The latest thinking is that an organized squall line or multiple line segments will be the primary storm mode. Extensive clouds and precipitation early in the day should limit atmospheric instability and hamper the development of severe storms. Even so, damaging straight-line thunderstorm winds remain a possibility.
The SPC’s next outlook for tomorrow comes early tomorrow morning, when it issues it’s first “Day 1 Convective Outlook” of the day.
Probabilities of any form of severe weather within 25 miles of a point between 8 a.m. EDT Wednesday, Sep. 10 and 8 a.m. EDT Thurs., Sep. 11. Purple: 45 percent. Red: 30 percent. Yellow: 15 percent. Brown: 5 percent. Highlighted counties: Northern Indiana NWS office county warning area. Source: SPC “Day 2 Convective Outlook” issued at 1:36 a.m. EDT.
Much of northern Indiana and surrounding parts of Illinois, Michigan and Ohio have a 45 percent probability of some form of severe weather within 25 miles of a point tomorrow, according to the “Day 2 Convective Outlook” that the National Weather Service (NWS) Storm Prediction Center (SPC) issued at 1:36 a.m. EDT.
To put that in perspective, the historical average probability of severe weather in that area at this time of year is only one percent, according to the SPC website. That means that tomorrow’s probability of severe weather is 45 times the normal probability. Here’s a link to a Web page that will provide a better understanding of outlook probabilities,
There is a chance that morning cloud cover tomorrow will limit atmospheric instability and therefore limit severe weather potential. But if that doesn’t happen, widespread swaths of severe wind gusts with peak gusts approaching 75 mph are possible. A couple of tornadoes are also possible as are heavy rainfall and localized flooding.
The area of 45 percent probability includes essentially all of the 37-county warning area of the northern Indiana NWS office and therefore all four quadrants of IMO SKYWARN.
SKYWARN storm spotters should spend some time today reviewing reporting criteria and methods, charging device batteries and generally preparing for possible activation tomorrow.
All residents of the area depicted in the map above who plan outdoor activities tomorrow should make sure they have a way of receiving notification of any severe thunderstorm or tornado warnings that the NWS issues (don’t rely on being able to hear an outdoor warning siren!). They should also identify in advance how they’ll notify others of a warning and where and how everyone will take shelter.
The northern Indiana NWS office plans to issue a multimedia briefing regarding tomorrow’s severe weather possibilities later this morning. I’ll post it on the “W9LW’s Ramblings blog” when it’s available.
The SPC will issue an updated “Day 2 Convective Outlook” by 1:30 p.m. today. I plan to update the blog after it comes out.
Please feel free to use the sharing links below to share this information with others via social networks, etc. Also, if you have an comments or questions, please use the comment link under the post title.
Probability of any form of severe weather within 25 miles of a point between 8 a.m. EDT Wednesday and 8 a.m. EDT Thursday. Red area: 30 percent (high end of “slight risk” criteria). Yellow: 15 percent (low end of slight risk). Brown: 5 percent (below “slight risk” criteria). Unshaded: Severe weather not expected. Highlighted counties: County warning area of northern Indiana NWS office. Source: SPC “Day 3 Convective Outlook” issued at 3:30 a.m. EDT.
The entire state of Indiana and the entire 37-county warning area (CWA) of the northern Indiana National Weather Service (NWS) office have a slight risk of severe weather between 8 a.m. EDT Wednesday and 8 a.m. EDT Thursday, according to a “Day 3 Convective Outlook” that the NWS Storm Prediction Center issued at 3:30 a.m. EDT.
“Severe storms are possible Wednesday across southern portions of the Great Lakes region into parts of the middle Mississippi and lower Ohio valleys. This will be accompanied by the risk for damaging wind gusts, possibly a couple of tornadoes, and could impact the Chicago, Detroit, Indianapolis and Cleveland metropolitan areas,” SPC meteorologists wrote.
As you can see in the map above, the probabilities of severe weather within 25 miles of a point are highest in northern Indiana, where they reach 30 percent, the high end of the SPC’s “slight risk” criteria. Day three outlooks provide combined probabilities and therefore indicate the likelihood of any of the following forms of severe weather:
Tornadoes.
Damaging straight-line thunderstorm winds of at least 58 mph.
Large hail of at least one inch in diameter.
Our next look at the severe weather outlook for Wednesday comes early tomorrow morning, when the SPC issues its first “Day 2 Convective Outlook” of the day.
Risk of severe weather Wed. and Wed. night. Brown area: Slight risk of severe storms, possibly including tornadoes. Unshaded area: Severe weather no expected. Highlighted counties: County warning area of the northern Indiana NWS office. Source: SPC “Day 4-8 Convective Outlook” issued at 5 a.m.
Approximately the northern two thirds of Indiana has a slight risk of severe weather between 8 a.m. EDT Wednesday, Sep. 10 and 8 a.m. EDT Thursday, according to a “Day 4-8 Convective Outlook” issued by the National Weather Service Storm Prediction Center at 5 a.m. EDT today. The risk area includes portions of other states near Indiana and all 37 counties of the northern Indiana NWS office’s county warning area (and therefore all of IMO SKYWARN’s quadrants).
Forecast conditions indicate “an increasing potential for a regional severe weather event,” which could include supercells and the evolution of an organized thunderstorm system, “accompanied by the risk for damaging wind gusts and a few tornadoes,” according to the SPC outlook.
The SPC will next update its outlook for the period by 5 a.m. EDT tomorrow.
…STRONG THUNDERSTORMS MOVING TOWARD SOUTHERN DEFIANCE…PAULDING… NORTHWESTERN VAN WERT…NORTHERN BLACKFORD…NORTHWESTERN JAY… NORTHERN GRANT…WELLS…NORTHERN ADAMS…SOUTHEASTERN MIAMI… HUNTINGTON…SOUTHEASTERN WABASH…SOUTHEASTERN WHITLEY AND ALLEN COUNTIES… AT 924 PM EDT…NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED View the full statement on the NWS website.
The northern Indiana office of the National Weather Service issued an updated “Hazardous Weather Outlook” at 3:34 p.m. EDT in which it advises SKYWARN storm spotters to “be prepared to send in reports as storms move through the area.” The full text appears below.
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORTHERN INDIANA
334 PM EDT FRI SEP 5 2014
INZ004>009-012>018-020-022>027-032>034-MIZ078>081-OHZ001-002-004-005-
015-016-024-025-061945-
ST. JOSEPH IN-ELKHART-LAGRANGE-STEUBEN-NOBLE-DE KALB-STARKE-PULASKI-
MARSHALL-FULTON IN-KOSCIUSKO-WHITLEY-ALLEN IN-WHITE-CASS IN-MIAMI-
WABASH-HUNTINGTON-WELLS-ADAMS-GRANT-BLACKFORD-JAY-CASS MI-
ST. JOSEPH MI-BRANCH-HILLSDALE-WILLIAMS-FULTON OH-DEFIANCE-HENRY-
PAULDING-PUTNAM-VAN WERT-ALLEN OH-
INCLUDING THE CITIES OF...SOUTH BEND...MISHAWAKA...ELKHART...
GOSHEN...LAGRANGE...TOPEKA...ANGOLA...KENDALLVILLE...LIGONIER...
AUBURN...GARRETT...KNOX...NORTH JUDSON...WINAMAC...FRANCESVILLE...
PLYMOUTH...BREMEN...ROCHESTER...WARSAW...WINONA LAKE...
COLUMBIA CITY...SOUTH WHITLEY...FORT WAYNE...MONTICELLO...
BROOKSTON...LOGANSPORT...PERU...WABASH...NORTH MANCHESTER...
HUNTINGTON...BLUFFTON...OSSIAN...DECATUR...BERNE...MARION...
HARTFORD CITY...MONTPELIER...PORTLAND...DOWAGIAC...CASSOPOLIS...
STURGIS...THREE RIVERS...COLDWATER...HILLSDALE...BRYAN...WAUSEON...
ARCHBOLD...DEFIANCE...NAPOLEON...PAULDING...ANTWERP...OTTAWA...
PANDORA...VAN WERT...DELPHOS...LIMA
334 PM EDT FRI SEP 5 2014 /234 PM CDT FRI SEP 5 2014/
THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST OHIO...
NORTHERN INDIANA AND SOUTHWEST LOWER MICHIGAN.
.DAY ONE...THIS AFTERNOON AND TONIGHT
THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND TONIGHT. SOME OF
THESE STORMS MAY BE SEVERE. THE MAIN RISK WILL BE WIND GUSTS UP
TO 65 MPH...BUT LARGE HAIL MAY ALSO BE POSSIBLE. LOCALLY HEAVY
RAINFALL IS EXPECTED WITH THESE STORMS AS WELL.
AFTERNOON TEMPERATURES WILL CLIMB TO THE LOWER 90S TODAY. COMBINED
WITH HIGH HUMIDITY...THIS WILL LEAD TO HEAT INDEX VALUES AROUND
100.
.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY
THUNDERSTORMS ARE POSSIBLE TUESDAY AND WEDNESDAY.
.SPOTTER INFORMATION STATEMENT...
SPOTTERS SHOULD BE PREPARED TO SEND IN REPORTS AS STORMS MOVE
THROUGH THE AREA.
&&
STAY TUNED TO NOAA WEATHER RADIO FOR FURTHER DETAILS OR UPDATES...OR
CHECK OUR WEB SITE AT WEATHER.GOV/IWX
$$
INZ003-MIZ077-061945-
LA PORTE-BERRIEN-
INCLUDING THE CITIES OF...MICHIGAN CITY...LA PORTE...NILES...
BENTON HARBOR...ST. JOSEPH...BUCHANAN
334 PM EDT FRI SEP 5 2014 /234 PM CDT FRI SEP 5 2014/
THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHERN INDIANA
AND SOUTHWEST LOWER MICHIGAN.
.DAY ONE...THIS AFTERNOON AND TONIGHT
THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND TONIGHT. SOME OF
THESE STORMS MAY BE SEVERE. THE MAIN RISK WILL BE WIND GUSTS UP
TO 65 MPH...BUT LARGE HAIL MAY ALSO BE POSSIBLE. LOCALLY HEAVY
RAINFALL IS EXPECTED WITH THESE STORMS AS WELL.
AFTERNOON TEMPERATURES WILL CLIMB TO AROUND 90 DEGREES TODAY.
COMBINED WITH HIGH HUMIDITY...THIS WILL LEAD TO HEAT INDEX VALUES
FROM THE MID 90S TO AROUND 100.
.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY
DANGEROUS SWIMMING CONDITIONS DUE TO HIGH WAVES AND STRONG RIP
CURRENTS ARE EXPECTED ALONG THE LAKE MICHIGAN SHORELINE ON
SATURDAY.
THUNDERSTORMS ARE POSSIBLE TUESDAY AND WEDNESDAY.
.SPOTTER INFORMATION STATEMENT...
SPOTTERS SHOULD BE PREPARED TO SEND IN REPORTS AS STORMS MOVE
THROUGH THE AREA.
&&
STAY TUNED TO NOAA WEATHER RADIO FOR FURTHER DETAILS OR UPDATES...OR
CHECK OUR WEB SITE AT WEATHER.GOV/IWX
$$
LMZ043-046-061945-
NEW BUFFALO MI TO ST JOSEPH MI-MICHIGAN CITY IN TO NEW BUFFALO MI-
334 PM EDT FRI SEP 5 2014
THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE NEARSHORE WATERS OF
SOUTHEASTERN LAKE MICHIGAN.
.DAY ONE...THIS AFTERNOON AND TONIGHT
THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND TONIGHT. SOME OF
THESE STORMS MAY BE SEVERE WITH STRONG WIND GUSTS...HAIL...AND
LOCALLY HIGHER WAVES.
CONDITIONS HAZARDOUS TO SMALL CRAFT ARE EXPECTED LATE TONIGHT.
.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY
HAZARDOUS CONDITIONS FOR SMALL CRAFT ARE EXPECTED TO CONTINUE
INTO SATURDAY.
THERE IS A CHANCE FOR THUNDERSTORMS TUESDAY AND WEDNESDAY.
&&
STAY TUNED TO NOAA WEATHER RADIO FOR FURTHER DETAILS OR UPDATES...OR
CHECK OUR WEB SITE AT WEATHER.GOV/IWX/?N=MARINE
Counties in blue: Severe thunderstorm watch until 9 p.m. EDT.
The National Weather Service has issued a severe thunderstorm watch, in effect until 9 p.m. EDT, for much of northern Indiana and nearby states. It includes all of IMO SKYWARN quadrant two except for Blackford and Jay Counties. The verbatim watch announcement appears below.
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 495
NWS STORM PREDICTION CENTER NORMAN OK
305 PM EDT FRI SEP 5 2014
THE NWS STORM PREDICTION CENTER HAS ISSUED A
* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
NORTHERN ILLINOIS
NORTHERN INDIANA
SOUTHERN AND EASTERN LOWER MICHIGAN
NORTHWEST OHIO
LAKE ERIE
LAKE HURON
LAKE MICHIGAN
* EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 305 PM UNTIL
900 PM EDT.
* PRIMARY THREATS INCLUDE...
SCATTERED DAMAGING WIND GUSTS TO 70 MPH LIKELY
ISOLATED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE
THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 75
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 15 MILES EAST
SOUTHEAST OF MOUNT CLEMENS MICHIGAN TO 65 MILES WEST OF
VALPARAISO INDIANA. FOR A COMPLETE DEPICTION OF THE WATCH SEE
THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.
&&
DISCUSSION...TSTMS EXPECTED TO INCREASE IN COVERAGE/STRENGTH ALONG
AND AHEAD OF ESE-MOVING COLD FRONT NOW APPROACHING THE WRN SUBURBS
OF CHICAGO AND WRN LWR MI. DEVELOPMENT ALSO MAY OCCUR ALONG
PRE-FRONTAL CONFLUENCE AXES AND LAKE BREEZE BOUNDARIES IN NRN IN/SRN
MI. BAND OF ELEVATED STORMS NOW FORMING E OF ROCKFORD IL MAY
INTENSIFY AS IT OUTPACES SFC COLD FRONT AND ENCOUNTERS GREATER
LOW-LVL INSTABILITY IN THE CHICAGO AREA OVER THE NEXT 1-2 HRS. THESE
STORMS...AND THOSE FORMING FARTHER E...WILL HAVE A TENDENCY TO
ORGANIZE INTO N-S LINES. ASSOCIATED EMBEDDED BOWS WILL POSE A RISK
FOR DMGG WIND AND POSSIBLY SVR HAIL THOUGH EARLY TNGT GIVEN VERY
WARM/MOIST LOW-LVL ENVIRONMENT...RESIDUAL EML...AND 35+ KT WSWLY
UNIDIRECTIONAL 700-500 MB FLOW.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM
MOTION VECTOR 26035.
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH OUTLINE UPDATE FOR WS 495
NWS STORM PREDICTION CENTER NORMAN OK
305 PM EDT FRI SEP 5 2014
SEVERE THUNDERSTORM WATCH 495 IS IN EFFECT UNTIL 900 PM EDT
FOR THE FOLLOWING LOCATIONS
ILC031-043-053-063-075-089-091-093-097-105-197-060100-
/O.NEW.KWNS.SV.A.0495.140905T1905Z-140906T0100Z/
IL
. ILLINOIS COUNTIES INCLUDED ARE
COOK DUPAGE FORD
GRUNDY IROQUOIS KANE
KANKAKEE KENDALL LAKE
LIVINGSTON WILL
INC001-003-007-017-033-039-049-069-073-085-087-089-091-099-103-
111-113-127-131-141-149-151-169-179-181-183-060100-
/O.NEW.KWNS.SV.A.0495.140905T1905Z-140906T0100Z/
IN
. INDIANA COUNTIES INCLUDED ARE
ADAMS ALLEN BENTON
CASS DE KALB ELKHART
FULTON HUNTINGTON JASPER
KOSCIUSKO LAGRANGE LAKE
LA PORTE MARSHALL MIAMI
NEWTON NOBLE PORTER
PULASKI ST. JOSEPH STARKE
STEUBEN WABASH WELLS
WHITE WHITLEY
MIC005-015-021-023-025-027-037-045-049-057-059-063-065-067-075-
077-087-091-093-099-115-125-145-147-149-151-155-157-159-161-163-
060100-
/O.NEW.KWNS.SV.A.0495.140905T1905Z-140906T0100Z/
MI
. MICHIGAN COUNTIES INCLUDED ARE
ALLEGAN BARRY BERRIEN
BRANCH CALHOUN CASS
CLINTON EATON GENESEE
GRATIOT HILLSDALE HURON
INGHAM IONIA JACKSON
KALAMAZOO LAPEER LENAWEE
LIVINGSTON MACOMB MONROE
OAKLAND SAGINAW SANILAC
SHIAWASSEE ST. CLAIR ST. JOSEPH
TUSCOLA VAN BUREN WASHTENAW
WAYNE
OHC003-039-043-051-063-069-077-095-123-125-137-143-147-161-171-
173-060100-
/O.NEW.KWNS.SV.A.0495.140905T1905Z-140906T0100Z/
OH
. OHIO COUNTIES INCLUDED ARE
ALLEN DEFIANCE ERIE
FULTON HANCOCK HENRY
HURON LUCAS OTTAWA
PAULDING PUTNAM SANDUSKY
SENECA VAN WERT WILLIAMS
WOOD
SEVERE THUNDERSTORM WATCH 495 IS IN EFFECT UNTIL 900 PM EDT FOR THE FOLLOWING LOCATIONS IN . INDIANA COUNTIES INCLUDED ARE ADAMS ALLEN BENTON CASS DE KALB ELKHART View the full statement on the NWS website.
…HEAT ADVISORY REMAINS IN EFFECT UNTIL 6 PM EDT /5 PM CDT/ THIS EVENING… HAZARDOUS WEATHER… * THE HEAT INDEX IS EXPECTED TO REMAIN AROUND 100 DEGREES THIS AFTERNOON OVER NORTHERN INDIANA AND NORTHWEST OHIO. IMPACTS… View the full statement on the NWS website.
