La Niña drawing to a close
La Niña, the cooling of the equatorial Pacific waters off the coast of South America that has dramatically affected our weather for most of the past two years, is almost done. Sea surface temperatures (SSTs) over the tropical Eastern Pacific in the area 5°N - 5°S, 120°W - 170°W, also called the "Niña 3.4 region", have warmed rapidly over the past two weeks, and were 0.4°C below average on February 27. This is slightly warmer than the -0.5°C threshold to be considered La Niña conditions, and is the first time since early August that La Niña conditions have not been present. It is likely that SSTs will continue to warm during March and April, and NOAA's Climate Prediction Center is predicting that they will declare an official end to La Niña sometime between March and April. A moderate to strong La Niña began in the summer of 2010, weakened briefly during May - July 2011 to neutral status, then re-intensified to a borderline weak/moderate La Niña from August 2011 - January 2012.

Figure 1. Comparison of the sea surface temperature departure from average from January 4 and February 22, 2012, over the tropical Eastern Pacific. During January, a large region of the ocean was more than 0.5°C cooler than average, meaning a La Niña event was present. Beginning in mid-February, waters warmed rapidly from east to west along the Equator, signaling and end to the La Niña event. Image credit: NOAA.
The forecast: neutral or El Niño conditions by fall
The period March - May is the typical time of year that El Niño or La Niña events end, and it is common for the opposite phenomena to take hold by fall. Since 1950, there have been twelve La Niña events that ended during the first half of the year; during six of those years (50%), an El Niño event formed in time for the August - September - October peak of hurricane season. The official forecast from Columbia University's IRI and NOAA's Climate Prediction Center calls for a 31 - 32% chance of an El Niño event during the 2012 Atlantic hurricane season. El Niño conditions tend to suppress Atlantic hurricane activity by creating high levels of wind shear that tends to tear hurricanes apart. Given the relatively high chance of an El Niño event this fall, plus ocean temperatures over the tropical Atlantic that are cooler than we saw in 2011 and 2010, I doubt we'll see an Atlantic hurricane season as active as the ones in 2010 and 2011 (nineteen named storms both years, third busiest seasons on record.) The demise of La Niña also means that global temperatures should begin to approach record warm levels by the end of the year. The cool waters of a La Niña event keep global temperatures cooler than average.

Figure 2. Computer model forecasts of El Niño/La Niña made in mid-February 2012. The forecasts that go above the red line at +0.5°C denote El Niño conditions; -0.5°C to +0.5°C denote neutral conditions, and below -0.5°C denote La Niña conditions. Most of the computer models are predicting neutral or El Niño conditions during the fall peak of the Atlantic hurricane season. Image credit: Columbia University's IRI.
I'll have a new post by Wednesday.
Jeff Masters
Reader Comments
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Likely.
Oh god. That's terrible. Several destructive tornadoes obviously occurred last night.
658 AM CST WED FEB 29 2012
THE NATIONAL WEATHER SERVICE IN PADUCAH HAS ISSUED A
* TORNADO WARNING FOR...
SOUTHEASTERN MCLEAN COUNTY IN NORTHWEST KENTUCKY...
NORTHERN MUHLENBERG COUNTY IN SOUTH CENTRAL KENTUCKY...
* UNTIL 730 AM CST.
* AT 654 AM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED 6 MILES NORTHWEST OF CENTRAL CITY...AND MOVING
EAST AT 50 MPH.
* LOCATIONS IN THE WARNED AREA INCLUDE...
CENTRAL CITY.
Is over my head here,but being long range,it will not be anything to be of a concern in terms of developing.
6:05 a.m. CST: A tornado was reported by a state trooper near Newburgh, Ind. Widespread damage occurred throughout the city proper. Rescue teams are responding.
5:37 a.m. CST: A tornado confirmed by a trained spotter in Harrisburg, Ill., caused extensive damage in the southeastern part of town. There are reports about a few deaths, but this has not yet been confirmed. Search and rescue is still in progress. Nearby, power flashes were observed with a possible tornado on the ground in Metropolis, Ill.
5:32 a.m. CST: The Associated Press is reporting that the person who died in Buffalo, Mo., was a resident of a mobile home park. A local sheriff also says that 13 others were injured when the tornado passed through the same trailer park. In addition, the AP is reporting at least a dozen injuries in Branson, where rescuers were combing through homes trying to help people who are trapped.
5:03 a.m. CST: A possible tornado touched down north and west of Mounds, Ill. A cross arm ripped off of a railroad sign and was launched through the vehicle of a trained spotter.
4:50 a.m. CST: A possible tornado destroyed a barn and chicken farm, damaged a house, and caused damaged numerous trees and power lines.
4:10 a.m. CST: Structural damage was reported in Oak Ridge, Mo., from a possible tornado, which was confirmed on the ground by spotters near Grand Tower, Ill., a short time later.
3:35 a.m. CST: Kansas Gov. Sam Brownback has declared a state of emergency in the state in the wake of tornado damage.
2:37 a.m. CST: There are additional reports of major structural damage and building collapses in Branson, Mo. All firefighters in the town have been told to report as rescues are ongoing.
1:35 a.m. CST: A confirmed tornado has damaged multiple structures in the town of Branson, Mo., including a hotel, restaurant and gas station.
1:25 a.m. CST: KOLR-TV in Springfield, Mo., is reporting that at least one person is dead in the wake of a tornado in Buffalo, Mo.
12:35 a.m. CST: Laclede County, Mo., Emergency Management reported debris falling from the sky in Lebanon, possibly from a nearby tornado.
11:48 p.m. CST: AccuWeather Enterprise Solutions Meteorologist Cory Mottice relayed a report of blown out windows and a barn destroyed by a possible tornado in Arcola, Mo.
11:30 p.m. CST: The first photo of potential tornado damage in Harveyville, Kan
MORNING SOUNDINGS AT LITTLE ROCK AND NASHVILLE SUGGEST THAT ONSET OF
DAYTIME HEATING MAY SUPPORT REJUVENATION OF EXISTING SQLN STORMS IN
KY AND NRN TN...AND POSSIBLY NEW DEVELOPMENT FARTHER SW ALONG
AFOREMENTIONED OUTFLOW BOUNDARY/WIND SHIFT LINE ASSOCIATED WITH THE
STORMS.
SATELLITE DERIVED /GPS PW DATA...AND OBSERVED SFC DEWPOINTS...
SUGGEST THAT DEEPLY MOIST LOW LVL ENVIRONMENT WILL BE PRESENT OVER
THE TN VLY. COUPLED WITH STRONG TO INTENSE LOW TO MID LVL WIND
FIELD...AND THE GRAZING INFLUENCE OF UPSTREAM VORT LOBE THIS
AFTN...POTENTIAL WILL EXIST FOR A FAIRLY CONCENTRATED CORRIDOR OF
SUPERCELLS FROM NRN MS ENEWD TO THE WRN SLOPES OF THE CNTRL/SRN
APPALACHIANS. A FEW OF THESE STORMS MAY BECOME LONG-LIVED AND
CAPABLE OF TORNADOES /ONE OR TWO OF WHICH COULD BE STRONG/...AND
SWATHS OF DMGG WIND.
THE STORMS SHOULD EVOLVE INTO A BROKEN QUASI-LINEAR MCS LATER THIS
AFTN AND TNGT. PART OF THE THIS SYSTEM MAY MOVE/DEVELOP E TO
VICINITY OF WARM FRONT IN SRN VA/NC...POSING AN OVERNIGHT SVR RISK
/INCLUDING ISOLD TORNADOES/ IN THAT REGION. THE OTHER PART OF THE
MCS MAY TEND TO BACK-BUILD AND/OR DEVELOP MORE SWD INTO NRN
AL/GA...WITH A DIMINISHING THREAT FOR SVR WEATHER CONTINUING INTO
EARLY THU.
FINALLY...N OF THE OH VLY SQLN...APPROACH OF UPSTREAM VORT LOBE AND
ASSOCIATED COLD FRONT MAY SUPPORT A FEW STORMS...POSSIBLY SVR...THIS
AFTN/EARLY TNGT IN ERN IND AND OH/WRN PA.
..CORFIDI/DEAN.. 02/29/2012
TORNADO REPORTED BY STATE TROOPER NEAR THE COMMUNITY OF NEWBURGH. WIDESPREAD DAMAGE THROUGHOUT THE CITY PROPER. RESCUE TEAMS ARE RESPONDING
Updated: Wednesday, 29 Feb 2012, 8:11 AM EST
Published : Wednesday, 29 Feb 2012, 7:49 AM EST
NEWBURGH, Ind. (WISH) - Emergency crews were seeing homes with severe damage on the far southern edge of Indiana Wednesday morning, after a likely tornado touched down near Newburgh.
Warrick County Sheriff’s Department officials say the tornado hit in the town east of Evansville around 6:10 a.m. local time, which is 7:10 a.m. in the Indianapolis metro area. Evansville is on central time. Initial reports indicate no one was seriously injured.
Newburgh Fire Department officials said they were battling fires throughout the area
Ouch!!!!. If only it was a little more south!!. Unfortunatly i will be away and unable to track these storms.
820 AM EST WED FEB 29 2012
THE NATIONAL WEATHER SERVICE IN LOUISVILLE HAS ISSUED A
* TORNADO WARNING FOR...
NORTHWESTERN BULLITT COUNTY IN NORTH CENTRAL KENTUCKY...
NORTHERN HARDIN COUNTY IN NORTH CENTRAL KENTUCKY...
EASTERN MEADE COUNTY IN NORTH CENTRAL KENTUCKY...
SOUTHEASTERN HARRISON COUNTY IN SOUTH CENTRAL INDIANA...
* UNTIL 845 AM EST...
* AT 818 AM EST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED NEAR ROCK HAVEN...MOVING EAST AT 55 MPH.
* THIS TORNADIC STORM WILL ALSO IMPACT...
SHEPHERDSVILLE...
CUPIO AND STITES...
BARRALLTON...
GAP IN KNOB AND FOX CHASE...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
IN ADDITION TO THE TORNADO...WIDESPREAD DAMAGING WINDS IN EXCESS OF
70 MPH ARE LIKELY. SEEK SHELTER NOW!
720 AM CST WED FEB 29 2012
THE NATIONAL WEATHER SERVICE IN PADUCAH HAS ISSUED A
* TORNADO WARNING FOR...
EAST CENTRAL HOPKINS COUNTY IN NORTHWEST KENTUCKY...
SOUTHEASTERN MCLEAN COUNTY IN NORTHWEST KENTUCKY...
NORTHWESTERN MUHLENBERG COUNTY IN SOUTH CENTRAL KENTUCKY...
* UNTIL 745 AM CST.
* AT 717 AM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED 7 MILES NORTHWEST OF GRAHAM...OR 8 MILES EAST OF
MADISONVILLE...AND MOVING EAST AT 75 MPH.
* LOCATIONS IN THE WARNED AREA INCLUDE...
LIVERMORE...SACRAMENTO...BREMEN...SOUTH CARROLLTON AND ISLAND.
824 am EST Wed Feb 29 2012
...A Tornado Warning remains in effect until 830 am EST for northern
Trimble and eastern Jefferson counties...
At 822 am EST...Weather Service Doppler radar continued to indicate a
severe thunderstorm with strong rotation. This dangerous storm was
located near monitor...moving east at 80 mph.
* This dangerous storm will also impact...
mainly rural areas of eastern Jefferson and northern Trimble
counties.
734 AM CST WED FEB 29 2012
THE NATIONAL WEATHER SERVICE IN LOUISVILLE HAS ISSUED A
* TORNADO WARNING FOR...
OHIO COUNTY IN NORTHWEST KENTUCKY...
* UNTIL 800 AM CST...
* AT 732 AM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED NEAR SMALLHOUS...MOVING EAST AT 70 MPH.
* THIS TORNADIC STORM WILL ALSO IMPACT...
HARTFORD...
MCHENRY AND SIMMONS...
BEAVER DAM AND SANDEFUR CROSSING...
HORSE BRANCH AND ROSINE...
OLATON...
Maybe you should read post 708. I posted it just right after the map was updated. Stay safe man!
740 AM CST WED FEB 29 2012
THE NATIONAL WEATHER SERVICE IN LOUISVILLE HAS ISSUED A
* TORNADO WARNING FOR...
EASTERN OHIO COUNTY IN NORTHWEST KENTUCKY...
NORTHERN BUTLER COUNTY IN SOUTH CENTRAL KENTUCKY...
CENTRAL GRAYSON COUNTY IN SOUTH CENTRAL KENTUCKY...
* UNTIL 815 AM CST...
* AT 736 AM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED NEAR BAIZETOWN...MOVING EAST AT 55 MPH.
* THIS TORNADIC STORM WILL ALSO IMPACT...
LEITCHFIELD...
WINDY HILL AND HORSE BRANCH...
ARNOLD AND WHITE RUN...
NEAFUS AND DOGWALK...
TILFORD AND DO STOP...
It is starting to concern me the conditions that are going to present in the Spring across the Midwest and points south. Everyone remembers the ridiculous tornado season that occurred in last year's conditions. This was the Gulf then...
Now this season we have vamped moisture levels in the Gulf versus last season on an order of about 1 degree C higher in all areas. Ample energy for any systems that get to tap into this Spring.
Beaver dam look out...
749 AM CST WED FEB 29 2012
THE NATIONAL WEATHER SERVICE IN LOUISVILLE HAS ISSUED A
* TORNADO WARNING FOR...
NORTHWESTERN GRAYSON COUNTY IN SOUTH CENTRAL KENTUCKY...
* UNTIL 815 AM CST...
* AT 746 AM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS
DANGEROUS STORM WAS LOCATED NEAR TOUSEY...MOVING NORTHEAST AT
55 MPH.
* THIS TORNADIC STORM WILL ALSO IMPACT...
SHORT CREEK...
DUFF AND CONCORD...
Impressive! Looks like it's going to be a rough day across TN. This reminds me of the April 8th 2006 event in TN. It seemed that afternoon every storm in TN had a tornado warning on it. That event has hit NW GA hard as well.
Tornado Warning
2012-02-29 09:07:23 EST until
2012-02-29 09:15:00 EST
806 am CST Wed Feb 29 2012
...A Tornado Warning remains in effect until 815 am CST for northern
Grayson County...
At 804 am CST...strong rotation was reported. This dangerous storm
was located 15 miles north of West Clifty...moving northeast at 125
mph.
* This dangerous storm will also impact...
mainly rural areas of northern Grayson County.
Moving 125 mph! Yikes
The National Weather Service in Louisville has issued a
* Tornado Warning for...
southern Grayson County in south central Kentucky...
* until 830 am CST...
* at 809 am CST... National Weather Service Doppler radar indicated a
severe thunderstorm capable of producing a tornado. This dangerous
storm was located near Peth... moving east at 55 mph.
* This tornadic storm will also impact...
Shrewsbury...
Grayson Springs and Peonia...
What??
A weak storm moving that fast coulb be severe!!
814 AM CST WED FEB 29 2012
THE NATIONAL WEATHER SERVICE IN LOUISVILLE HAS ISSUED A
* TORNADO WARNING FOR...
CENTRAL GRAYSON COUNTY IN SOUTH CENTRAL KENTUCKY...
* UNTIL 830 AM CST...
* AT 809 AM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
A SEVERE THUNDERSTORM WITH VERY STRONG ROTATION CAPABLE OF
PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED NEAR
CANEYVILLE...MOVING EAST AT 50 MPH.
* THIS TORNADIC STORM WILL ALSO IMPACT...
LEITCHFIELD...
BLACK ROCK...
CLARKSON...
Click for full size image
That's likey a strong tornado on the ground heading right into Leitchfield, KY. That is something you never want to experience especially one moving that fast.
819 AM CST WED FEB 29 2012
THE NATIONAL WEATHER SERVICE IN PADUCAH HAS ISSUED A
* TORNADO WARNING FOR...
SOUTH CENTRAL CALDWELL COUNTY IN WESTERN KENTUCKY...
CENTRAL CHRISTIAN COUNTY IN SOUTH CENTRAL KENTUCKY...
NORTHEASTERN TRIGG COUNTY IN WESTERN KENTUCKY...
* UNTIL 845 AM CST.
* AT 815 AM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED NEAR CADIZ...AND MOVING EAST AT 60 MPH.
* LOCATIONS IN THE WARNED AREA INCLUDE...
HOPKINSVILLE.
2012-02-29 09:24:01 EST until
2012-02-29 09:45:00 EST
822 am CST Wed Feb 29 2012
...A Tornado Warning remains in effect for central Christian County
in south central Kentucky...and south central Caldwell and
northeastern Trigg counties in western Kentucky until 845 am CST...
At 820 am CST...trained weather spotters reported a funnel cloud.
This tornado was located 5 miles east of Cadiz...moving east at 60
mph. This storm will cross I-24 near Exit 65.
Precautionary/preparedness actions...
To repeat...a tornado is on the ground.
WOW!
Click for larger image.
825 AM CST WED FEB 29 2012
THE NATIONAL WEATHER SERVICE IN LOUISVILLE HAS ISSUED A
* TORNADO WARNING FOR...
SOUTHWESTERN HARDIN COUNTY IN NORTH CENTRAL KENTUCKY...
EASTERN GRAYSON COUNTY IN SOUTH CENTRAL KENTUCKY...
* UNTIL 845 AM CST/945 AM EST/...
* AT 823 AM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
A SEVERE THUNDERSTORM WITH STRONG ROTATION CAPABLE OF PRODUCING A
TORNADO. A WALL CLOUD HAS BEEN REPORTED NEAR CANEYVILLE. THIS
DANGEROUS STORM WAS LOCATED NEAR LEITCHFIELD...MOVING EAST AT 45
MPH.
* THIS TORNADIC STORM WILL ALSO IMPACT...
LEITCHFIELD...
GRAYSON SPRINGS AND CLARKSON...
HORNTOWN AND FRAGRANT...
LACON AND SPURRIER...
WHITE MILLS AND WHITE MILLS JUNCTION...
Click for larger image
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