Severe Weather Threat – updated 3:30 AM Weds.

April 18th, 2013 at 1:09 am by under Bill's Blog, Weather

1630 UTC Day 1 Outlook 1630 UTC Day 2 Outlook      These are the Day 1 and Day 2Severe Weather Outlooks from the Storm Prediction Center.  Parts of S. Michigan are included in the Thursday outlook and there is a moderate risk are for today SE of Grand Rapids.  SPC keeps moving the Risk Area is from Lake Huron to the Gulf of Mexico.   Bouncing around facebook and weather websites, a lot of storm chasers will be out today, including four of our local chasers.  SPC says:  “ERN TX TO LOWER MI – TSTMS WILL ORGANIZE INTO AN EXTENSIVE SQUALL LINE ALONG THE COLD FRONT WITH MCS EXPECTED TO EXTEND FROM NRN IL…SWWD ACROSS MO INTO NERN TX AT SUNRISE.   LATEST THINKING IS EARLY MORNING SQUALL LINE WILL REMAIN ORGANIZED AS IT SURGES EWD.  THERE IS REASON TO BELIEVE BOW-TYPE STRUCTURES COULD EVOLVE ALONG THE SQUALL LINE GIVEN THE FAVORABLE SHEAR…IN ADDITION TO EMBEDDED SUPERCELLS THAT COULD PRODUCE ISOLATED TORNADOES.  IF MODELS CONTINUE TO DEPICT SUFFICIENT BUOYANCY THERE MAY BE AN ENHANCED RISK OF AN EXTENSIVE DAMAGING WIND EVENT WITH THIS ELONGATED CONVECTIVE COMPLEX.  WILL MAINTAIN 30 PERCENT SEVERE PROBS BUT THERE IS SOME CONCERN THIS MAY NEED TO BE UPGRADED IN LATER OUTLOOKS.”.

Here’s what the GRR NWS said:  “UPPER LEVEL DYNAMICS WITH THIS SYSTEM ARE IMPRESSIVE…AS WELL AS VERY STRONG UPPER LEVEL WINDS  SUPPORT POTENTIAL FOR A FEW TORNADOES. THIS IN ADDITION TO LARGE  HAIL AND STRONG WIND THREATS. THE GREATEST POTENTIAL FOR SEVERE WX  SHOULD COME THURSDAY AFTERNOON THROUGH THURSDAY EVENING

”    Check out Regional radar to see the rain across the Great Lakes. Here’s GRR radar, local lightning data, meso-discussions and current watches from SPC and a satellite loop. Here’s current Michigan temperatures. Here’s National lightning data. Here’s the latest discussion from GRR NWS. Here’s National Storm Reports for today and yesterday.

130 Responses to “Severe Weather Threat – updated 3:30 AM Weds.”

  1. Steven (Mt. Pleasant) says:

    I don’t know what the last day 2 outlook said, but most of lower Michigan is now in the slight risk area. Our first chance of severe weather for the season!

  2. Mike says:

    DAY 2 CONVECTIVE OUTLOOK
    NWS STORM PREDICTION CENTER NORMAN OK
    1215 PM CDT WED APR 17 2013

    VALID 181200Z – 191200Z

    …THERE IS A MDT RISK OF SVR TSTMS FOR SWRN LOWER MI…ERN/SRN
    IL…WRN/NRN IND…SERN MO…FAR WRN KY/TN…ERN AR…NWRN MS…FAR
    NERN LA…

    …THERE IS A SLGT RISK OF SVR TSTMS FROM THE GREAT LAKES TO THE
    WRN/CNTRL GULF COAST…

    …SIGNIFICANT SEVERE WEATHER EPISODE CONSISTING OF POTENTIALLY
    WIDESPREAD DAMAGING WINDS AND SEVERAL TORNADOES APPEARS INCREASINGLY
    LIKELY ON THU…

    …SYNOPSIS…
    AN AMPLIFIED UPPER-LEVEL TROUGH CENTERED FROM THE NRN PLAINS TO THE
    SOUTHWEST AT 12Z/THU WILL PROGRESS EWD ACROSS THE UPPER MS VALLEY TO
    THE SRN PLAINS THROUGH EARLY FRI. A VIGOROUS SHORTWAVE IMPULSE WILL
    EJECT FROM THE CNTRL PLAINS TO WI/IL WITH AN INTENSE AND
    STRENGTHENING MID-LEVEL SPEED MAX /AOA 100 KT/ OVERSPREADING THE
    MIDWEST. AT THE SURFACE…CYCLOGENESIS WILL CONTINUE FROM THE IA/IL
    BORDER NEWD TOWARDS NRN LK MI. AN ATTENDANT COLD FRONT WILL SWEEP
    EWD LIKELY REACHING LK MI TO THE LOWER MS VALLEY BY THU EVENING. A
    WARM FRONT WILL ATTEMPT TO ADVANCE NWD IN LOWER MI…WITH LOWER
    CONFIDENCE IN HOW FAR N IT WILL EXTEND WITH ABUNDANT CONVECTION
    EXPECTED N OF THE BOUNDARY.

    …GREAT LAKES TO THE WRN/CNTRL GULF COAST…
    FAIRLY EXTENSIVE BANDS OF CONVECTION SHOULD BE ONGOING AT 12Z/THU
    ALONG BOTH FRONTAL ZONES. DIURNAL HEATING WITHIN A RICHLY MOIST AIR
    MASS FROM THE WRN GULF INTO THE MIDWEST CHARACTERIZED BY 60S TO
    LOWER 70S SURFACE DEW POINTS AMIDST A REMNANT EML PLUME EMANATING
    N/NEWD ACROSS THE S-CNTRL CONUS…SHOULD RESULT IN A MODERATELY
    UNSTABLE WARM SECTOR WITH MLCAPE REACHING 1000-2000 J/KG.
    LOWER-LEVEL SHEAR/HODOGRAPHS WILL BE IMPRESSIVELY LARGE WITH NRN
    EXTENT ACROSS THE BULK OF THE WARM SECTOR. THESE FACTORS COMBINED
    WITH STRONGLY FORCED ASCENT WILL LIKELY YIELD AN EXTENSIVE QLCS THAT
    WILL INTENSIFY AND INCREASE IN FORWARD SPEED DURING THE LATE MORNING
    THROUGH THE AFTERNOON. BOWING SEGMENTS AND EMBEDDED SUPERCELLS WILL
    BE FAVORED…ESPECIALLY WITH NRN EXTENT GIVEN THE DEGREE OF SHEAR.
    POTENTIAL WILL ALSO EXIST FOR DISCRETE SUPERCELLS DEVELOPING AHEAD
    OF THE QLCS AS MLCIN BECOMES MINIMAL. THIS WOULD SEEM TO BE MORE
    PREVALENT WITH SRN EXTENT WHERE LARGE-SCALE ASCENT WILL BE
    PROGRESSIVELY WEAKER. SWATHS OF WIDESPREAD DAMAGING WINDS APPEAR
    PROBABLE ALONG WITH A ROBUST TORNADO RISK /SOME OF WHICH COULD BE
    SIGNIFICANT/. THE OVERALL SEVERE THREAT WILL LIKELY DIMINISH BY LATE
    EVENING/OVERNIGHT AS THE SURFACE MOISTURE PLUME IS PINCHED OFF WITH
    NRN EXTENT GIVEN DOWNSLOPE DRYING OFF THE SRN APPALACHIANS INTO THE
    CNTRL/UPPER OH VALLEY.

    ..GRAMS.. 04/17/2013

  3. Zach says:

    New Mesodiscussion for our area on Severe Weather Potential… watch however is unlikely

    http://mesodiscussion.com/view/20130492/

  4. Mike Geukes says:

    MESOSCALE DISCUSSION 0492
    NWS STORM PREDICTION CENTER NORMAN OK
    1226 PM CDT WED APR 17 2013

    AREAS AFFECTED…SW MICHIGAN

    CONCERNING…SEVERE POTENTIAL…WATCH UNLIKELY

    VALID 171726Z – 171830Z

    PROBABILITY OF WATCH ISSUANCE…20 PERCENT

    SUMMARY…A FEW STRONGER THUNDERSTORMS ARE EXPECTED THIS AFTERNOON.
    WHILE A MARGINALLY SEVERE WIND GUST AND SOME SMALL HAIL IS
    POSSIBLE…OVERALL SEVERE THREAT IS EXPECTED TO REMAIN LOW AND A WW
    IS NOT ANTICIPATED AT THIS TIME.

    DISCUSSION…CONVECTION CURRENTLY ONGOING UPSTREAM ACROSS NRN IL
    WILL CONTINUE TO SHIFT E/NE ACROSS SRN LAKE MICHIGAN INTO SW
    MICHIGAN THIS AFTERNOON. WHILE THESE STORMS ARE LIKELY TO REMAIN
    ELEVATED GIVEN COOL BOUNDARY LAYER WELL TO THE NORTH OF A WARM FRONT
    ACROSS THE OHIO VALLEY…STRONG EFFECTIVE SHEAR WILL OVERSPREAD THE
    AREA. IN CONJUNCTION WITH MODEST MIDLEVEL LAPSE RATES AND SOME WEAK
    INSTABILITY…AN ISOLATED STRONG/SEVERE WIND GUST MAY BE POSSIBLE IN
    STRONGER CELLS. COLD TEMPERATURES ALOFT /-10 TO -15 C AT 500 MB/ MAY
    ALSO SUPPORT SMALL HAIL PRODUCTION. OVERALL SEVERE THREAT SHOULD
    REMAIN SUFFICIENTLY LOW THAT A WW DOWNSTREAM OF SEVERE WATCH 113 IS
    NOT ANTICIPATED AT THIS TIME.

    ..LEITMAN/KERR.. 04/17/2013

  5. blharr44 says:

    Anyone looked at the new day 2 outlook in Bills blog. I can’t remember a time when we were in a 45% cross hatched area in Michigan.

    1. Cort S. says:

      It happens every now and then when a long line of storms is expected along a cold front stretching from Michigan to the Gulf states.

      A recent example that I can recall off the top of my head, October 26, 2010:

      http://www.spc.noaa.gov/exper/archive/outlook_panels.php?prod=day2&date=20101025_1730

      http://www.spc.noaa.gov/exper/archive/outlook_panels.php?prod=day1&date=20101026_1300

      1. blharr44 says:

        Thanks for the speedy reply… Do you know what ever became of that day as I don’t remember

        1. Cort S. says:

          October 26, 2010, was the day of the lowest low pressure system ever recorded in Minnesota. A very strong cold front pushed through in the late morning, forcing a long line of thunderstorms.

          Storm reports:
          http://www.spc.noaa.gov/exper/archive/event.php?date=20101026

          A tornado watch was issued for us at 11 AM:
          http://www.spc.noaa.gov/products/watch/2010/ww0724.html

          There was a rotating storm that triggered a tornado warning from NW of Kalamazoo to near Lowell. Kent County sounded their sirens county-wide, which really upset and confused a lot of people in Grand Rapids because there wasn’t any thunder in GR. People called it a fail, but really they don’t know how lucky they were…a shallow layer of cold, stable air near the ground prevented a lot of tornadoes and strong winds from reaching the ground in Michigan.

          Following the cold front, there were some 40-60+ mph winds across Michigan and the Midwest from that intense low-pressure system.

    2. Travis (Oakland County) says:

      Yep, we’ve gotten 60% and High Risk before… but it’s still fairly unusual.

  6. INDY says:

    Strting to get verry active outside we have major storms on the way with heavy rain tornadoes and wind look for lots of severe weather in Michigan the next 3 days starting this afternoon around 330pm in Grand Rapids…..Stay tuned INDYY..

  7. Jeff (Richland) says:

    Wow tomorrow could get crazy!!!

    1. GunLakeDeb says:

      I know this is a weather blog and people are looking forward to severe storms…. but I’ll be hoping for a giant “Fail”. I’m NOT a Spotter because I love storms – I’m a Spotter because I’m scared of them.

      1. Lindie (Twin Lake) says:

        Deb, you’re a girl with some good common sense! :) Go away, storms. I read here only in hopes that they go away.

  8. Skywarn training is given in multi-media style, but there are some books/handouts. Here is the spotter guide – printed copies are given out at the trainings only: http://skywarn.org/wp-content/uploads/basicspot.pdf
    Here is a cloud poster: http://www.nws.noaa.gov/om/brochures/cloudchart.jpg

  9. bnoppe(Albion) says:

    I wouldn’t be shocked to see the MOD Risk pushed further north with the overnight update looking at the SPC write up they simply didn’t have enough confidence to do it yet . A
    WARM FRONT WILL ATTEMPT TO ADVANCE NWD IN LOWER MI…WITH LOWER
    CONFIDENCE IN HOW FAR N IT WILL EXTEND WITH ABUNDANT CONVECTION
    EXPECTED N OF THE BOUNDARY.

  10. Swatz_Zoo(Cedar Springs) says:

    Makes me a bit leary on this call, we’ve seen these calls before and it turns out to be nothing or just general T-Storms, I haven’t ached at all my flock doesn’t have their tail feathers in a bunch, and usually that gives me a good indication something BIG is brewing but I can’t always go on feel of my Bodometer. That being said, there is a weird feeling to the atmosphere.

  11. INDY says:

    Train of rain is on its way….Get your flood plan ready now…INDYY..

    1. GunLakeDeb says:

      No kidding! At least everyone has had sufficient warning – and yet we’ll still see the people who say afterwards “We lost everything”…. sigh….

  12. Johnnie(Vicksburg) says:

    Rumble of thunder and light rain here.

  13. kwoodworrier says:

    NOW I’M REALLY SCARED WE WILL GET A TORNADO :( :(

  14. Red in Allegan Co. says:

    Some nice thunder rolling in now.

    1. Cort S. says:

      Good catch. These storm cells will have some chaotic wind fields within them, and if good outbound and inbound winds get snuggled up next to each other, it may trip the automated “TVS” marker.

      Since these storms are currently based on warm, unstable air thousands of feet above the ground, it will be very difficult for any strong winds or rotation to reach down to the ground. If the warm front lifts north of us tomorrow, it may be a different story.

      1. Thanks for the explanation Cort – I was thinking maybe water spout?!

        1. Cort S. says:

          Probably not. The winds that the radar is scanning aloft are likely quite different than what they are at the water/ground. We’re stuck in a wedge of cold air underneath the warm frontal air aloft, and the winds aloft are disconnected from the winds at the ground:

          http://commons.wikimedia.org/wiki/File:Example_of_a_warm_front.svg

          Waterspouts are more common in the late summer and fall when the water temperatures are warm and the air aloft is cold, which creates a surface-based instability that makes warm air at the ground rise and create a shower with a waterspout.

  15. Jerrod (Hartford) says:

    Back on the blog for the first time in months — winter sort of bores me. Anyways, latest NWS discussion came out from GRR just shy of 4 PM. Doesn’t mention hazards for severe, although wind, hail and tornadoes are possible. Only mention is best bet for severe southeast (it says SO but it makes no sense) from Kalamazoo to Lansing after 3 PM tomorrow. Discussion text on Severe is below, correct me if I’m wrong:

    AS FOR THE SEVERS STORM THREAT… WITH THE FRONT TO OUR WEST AND
    LOW LEVEL JET WEST OF AREA INTO THE LATE AFTERNOON IT MEANS
    SOUTHWEST MICHIGAN WILL BE IN THE WARM SECTOR OF THE STORM. THE
    SOUTHEAST CWA WILL SEE THE MOST SUNSHINE AND HAVE THE GREATEST INSTABILITY.
    A 60 KNOT LOW LEVEL JET DEVELOPS OVER SOUTHWEST MICHIGAN THURSDAY
    AFTERNOON AND STRENGTHENS TO 70 KNOTS OVER LAKE HURON BY EARLY
    FRIDAY MORNING. I WOULD EXPECT THE GREATEST THREAT FOR SEVERE
    STORMS WILL BE SO OF A LINE FROM AZO TO LANSING AFTER 3 PM.

    1. That’s a bit further north than previously forecasted. They were stating greatest threat along or south of I-94.

      1. Jerrod (Hartford) says:

        And actually, a bit further to the East. And that Hazardous Weather Outlook being three hours old, new information is likely coming in. Or a different forecaster has looked over the data.

    2. The Hazardous Outlook from 1:30 says: DAYS TWO THROUGH SEVEN…THURSDAY THROUGH TUESDAY

      A LINE OF STRONG TO SEVERE THUNDERSTORMS IS EXPECTED THURSDAY
      AFTERNOON AND EVENING. THE MAIN THREAT WILL BE DAMAGING WINDS AND
      HAIL. ISOLATED TORNADOES ARE ALSO POSSIBLE. THE STRONGEST STORMS ARE
      EXPECTED TO BE NEAR AND SOUTH OF INTESTATE 94 DURING THE AFTERNOON
      INTO THE EARLY EVENING.

  16. Brian(Grandville) says:

    Just got hammered with 1/4-1/2 inch hail for about 3 minutes.

  17. Eric says:

    What is the updated for friday aka tomorrow cause it looks like alot of schools might close from this

  18. Kimoeagle says:

    Nasty stuff down here: a line from Millersburg,IN to Syracuse,IN to Warsaw moving E at 40kts..winds to 40mph, hail 1/2 diameter….should hit FWA shortly…….

  19. Kinsey says:

    How big of a chance is it that there will be tornadoes tomorrow? Will it really be all that it is cut out to be in Grand Rapids? Tomorrow. Out of any day of the year!!!

    1. bnoppe(Albion) says:

      Fairly low Tornado chance, it looks like a nice line of storms will form and that could have an embedded weak tornado but I’d be more concerned with the damaging winds potential and the flooding rains

  20. Bruiseviolet (Cedar Springs) says:

    I hate when the chance is while my kids are still in school.

  21. Look at this long line of convective activity. PWAT values are too high…. rain and storms are just all over the place. http://www.spc.noaa.gov/exper/mesoanalysis/s20/rgnlrad/rgnlrad.gif?1366269216827

    1. Jack says:

      Nice, Thanks 4 theee Link, Charles.

  22. hurricane hunter says:

    Tornado watch? Not getting my hopes up.

  23. Mindy ( Mason MI ) says:

    Wow, i had more TS last night in the cold air!!! I had a good one at 4 am with lots of lightning and very loud thunder!!! I had no thunder when the line moved thru, rained hard for 5 minutes and tha was it, it really blew up just east of me on 127. I even filled up my Generator just in case!!! Every time when a watch is issued NOTHING HAPPENS!!!!!

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