Severe thunderstorm watch for w texas and west and central oklahoma until 11 am

First Major Severe Weather Outbreak of 2011 Possible Thursday!

System drawing moisture from the Gulf

It appears probable that a fairly significant severe weather outbreak is taking shape for Wednesday night into Thursday. A low pressure system will move through the Southern Plains into Dixie Alley Wednesday night into Thursday afternoon and evening. It appears an early round of thunderstorms across W Oklahoma could will develop Wednesday night, and move across the state through morning. This first round of storms main threat will be large hail and possibly damaging winds. Thursday afternoon, storms are expected to form ahead of a dryline bulge and along a warm front across E Oklahoma. Along with large hail and damaging winds, isolated tornadoes will be possible with these storms. At the moment, it appears the greatest threat for severe weather will begin in Central Oklahoma and move across the state into Arkansas. The severe weather threat could continue eastward overnight, although instability will be limited, so the main threat will probably be damaging winds. Stay tuned for further information regarding this event.

Day 3 Convective Outlook Valid Thursday, 2/24

Another Round of Snow Expected for the Southern Plains

    Another round of snow is expected today through tomorrow in parts of Kansas, Oklahoma, and Texas, as well as surrounding areas. This comes a week after the crippling snowstorm that hit the same areas, making travel nearly impossible last week. Just as these areas recovered, there may be a significant snowfall tonight through tomorrow afternoon as well. The heaviest snow is expected to be in areas of Southern Kansas into Central Oklahoma, where 6 to 10 inches of snow is possible, with isolated areas receiving up to a foot of snow.

    Although this could be a fairly major storm, there does seem to be some hope for warm weather. Temps are expected to rise into the lower to mid 60's by Sunday, and continue through next week. This will bring much needed relief to areas affected by this storm and last weeks storm.

    If traveling in any of the affected areas tonight or tomorrow, use extreme caution, and stay updated on the latest weather forecasts.

Donovan Gruner

"Snowpocalypse". Historic Storm Upon Us?

    This could be a record breaking or near record breaking storm for much of the country.  Latest model runs put a band of extremely heavy snow over Central Oklahoma into SE Kansas. Some areas from Oklahoma City to Chicago are expected to receive at least a foot of snow, and locally some areas may receive up to 2 feet! Strong winds will also complicate things, and areas that receive the highest amounts of snow could see snow drifts up to 8 feet or more. Blizzard Warnings are in effect in 7 states, and reach from Oklahoma City to Chicago and Milwaukee.

    The southern edge of the storm will bring significant icing to areas along the I-44 corridor in Oklahoma and especially Missouri. The ice threat also stretches across Illinois to New England. Some of the hardest hit areas will be St. Louis, Indianapolis, and Pittsburgh.

Ice Accumulations Through Wednesday

    This is a very dangerous storm, and many areas can expect major power outages along with incredibly heavy snow, freezing rain, sleet, and bitter cold wind chills. Several states including Oklahoma, Missouri, and Illinois have been declared to be in a State of Emergency. Stay tuned to your local news and NOAA Weather Radios for up to date details on the storm, and DO NOT travel unless ABSOLUTELY neccesary. If travel is unavoidable, dress in layers and bring food, water, and blankets in case you become stranded. This is a life threatening situation.

What the NWS has to say in it's Forecast Discussions:
   
      Norman, OK: Obvious analog would be Christmas Eve '09. For some this may be as bad or worse.  (That was Okla. City's record snowy day...13.5")
   
      Kansas City, MO: "This could end up being one of the more significant weather events in the last 20 years in Missouri."
   
      St. Louis, MO: "Potentially historic winter storm headed for region."
   
      Milwaukee, WI: Potentially "paralyzing blizzard" possible in southeast Wisconsin. Jan. 1999 blizzard produced 4-8 foot drifts!
   
      Grand Rapids, MI: "Travel...and commerce in general...could be paralyzed with near record-breaking snowfall."
   
      Indianapolis, IN: "(Ice and blizzard conditions) could result in devastating conditions for central Indiana. Long duration power outages appear possible."

Donovan Gruner

Extreme Winter Storm to Impact Much of the Country

     Strong disturbances associated with two jet streams will develop into a major winter storm for much of the country on Monday through the week. The jet stream is bringing very cold arctic air down from Canada and kicking off the storm by bringing moderate snowfall amounts to much of the Northern Plains and Great Lakes regions. To the south, a wintery mix will begin Monday night in the Oklahoma Panhandle and Southern Kansas before spreading eastward into Missouri. Snow will then begin falling over parts of Central Oklahoma Monday night into Tuesday. 

     A PDS (Particularly Dangerous Situation) Winter Storm Warning is in effect for Central and Northeastern Oklahoma.

     A Blizzard Watch is in effect for much of Northern and Central Illinois and Northwest Indiana, where strong winds and extremely heavy snowfall rates will combine to produce blizzard conditions. As much as 20 inches of snow at a rate of 3 inches per hour are possible in these areas.

GFS showing snow depth by Tuesday afternoon

NAM showing more extreme snowfall totals up to 20+ inches from Central Oklahoma through Missouri, Illinois and Michigan

Warm Air to Invade Southern Plains

Models are showing a "heat wave" moving into the Southern Plains at the end of the week, showing temperatures up to 70 degrees in many parts of Oklahoma and Texas. However, they are also showing a possible cold streak next week, with a possibility of a period of wintery precipitation.

November Tornado In N. Illinois As Shown By Radar

    Northern Illinois is beginning to grow accustomed to strange out of season tornadoes. On January 7th, 2008, an EF-3 tornado with wind speeds as high as 160 mph ripped through Boone and McHenry Counties.  Then, on November 22nd, another strange out of season tornado touched down, in nearly the same place. Had it touched down earlier, however, we may have had an entirely different situation on our hands.

11/22 tornadic supercell with visible BWER (bounded weak echo region, area of lower reflectivity sw of Loves Park and nw of Rockford) associated with the storm's updraft, and sometimes a precursor to tornadogenisis.

    These radar images (Storm Relative Velocity) depict the motion of particles within the storm. The doppler radar is able to detect this the same way as a police radar detects the speed of a vehicle. Meteorologists are able to use this product to detect rotation within thunderstorms, and sometimes detect tornadoes.

    This is the SRV at 2:51 pm. Although the radar is picking up some rotation just northwest of downtown Rockford, there is no tornado warning, possibly because the rotation isn't quite strong enough to validate a warning at the time. HOWEVER:

     Seen here is the same storm, but viewed at a higher elevation, ten minutes earlier (2:41 pm). There is very strong rotation at around 13kft, just southeast of Winnebago.

      Here you can clearly see the meso tighten up. This is at about 6,500 ft. The velocity couplet is now exhibiting strong maxed out velocities in both directions. This image is at about 2:56 pm, four minutes before the tornado warning was issued.

      At 3:00 pm, the NWS Chicago issued a tornado warning for Winnebago, Boone, and McHenry counties...

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A* TORNADO WARNING FOR...
NORTHERN BOONE COUNTY...
NORTHWESTERN MCHENRY COUNTY...
EAST CENTRAL WINNEBAGO COUNTY...
* UNTIL 330 PM CST
* AT 300 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED NEAR LOVES PARK...AND MOVING NORTHEAST AT 50 MPH.
* LOCATIONS IMPACTED INCLUDE...
HARVARD...POPLAR GROVE AND CAPRON.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.
&&
LAT...LON 4249 8856 4240 8846 4222 8895 4238 8909
4250 8888
TIME...MOT...LOC 2103Z 237DEG 42KT 4236 8892

     Unfortunately, judging by radar images, this warning was only issued about a minute or possibly less before the tornado was on the ground.

      This image shows the tight circulation crossing I-39/90 at 3:00, when the first tornado warning was issued. The tornado touched down right around this area.

Tornado path very distinct just after I-39/90 (center of image) near Rock Cut State Park (right)

     At this point, reports were coming in of a tornado on the ground. The tornado continued on, mostly through fields, before reaching Caledonia.

     Here the velocity couplet is shown entering Caledonia. Most of the most devastating damage done by this storm was in the Caledonia area, where the tornado's winds were likely reaching up to around 135 mph or more.

Image as tornado moves away from Caledonia at 3:09 pm.

Tree damage at Beloit Rd.

    All in all, Rockford and surrounding areas lucked out big time on this one. If this tornado would have touched down even 5 minutes earlier, it likely would have ripped through parts of Rockford and Loves Park.  Ten minutes earlier, and it would have ripped nearly right across town. The damage would have been far worse, being more structures "strengthen" the tornado in a way, giving it more power by turning it into a massive "blender".  Not to mention, it would have moved through a much more heavily populated area.

    Although the tornado did do quite a bit of damage in Boone and McHenry counties, luckily nobody was seriously injured. This storm also went on to produce an EF-1 tornado just over the state line.

Donovan Gruner