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June 22-23 Severe Weather Outbreak


Stebo

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He knows the probabilities and what makes a high end event but he is wondering which one of these probabilities (wind or tornado or hail) will be the ones to get the category tomorrow to the moderate risk.

I vote all, or at least TOR/Wind. Thinking a combo of 15/45/45 all hatched, maybe not all overlapping though

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as mentioned above, NMM takes the MCS from SD and doesn't even get into the far nw LOT CWA until after 18utc, so destabilization may already be underway...the potential for a real long track event is on the table here, to say nothing about how much of the afternoon potential is realized.

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I'd agree. I say 45 wind and hail over Nrn IL and Srn Wisco, 15 torn over Srn/Cent. Wisco -- all hatched, of course

There's almost certainly going to be 30% hatched hail or so in portions of IL where there's extreme buoyancy and steep mid level lapse rates. I could personally see a 15% hatched tornado risk for portions of Western Michigan and depending on what happens tomorrow AM, we could possibly see a very large area of 45% wind risk. 

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While we're guessing probabilities and stuff, tomorrow really looks legit from a hail perspective. Would not at all be surprised to see multiple cells producing baseball-softball size hail.

Yeah large CAPE density on the soundings.
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Lawrence at APX went full weenie in his AFD regarding tomorrow.

 

It's hard not to feel good about the potential after reading it...

 

 


000
FXUS63 KAPX 211933
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
333 PM EDT SUN JUN 21 2015

 

.SHORT TERM...(MONDAY THROUGH WEDNESDAY)
ISSUED AT 333 PM EDT SUN JUN 21 2015

HIGH IMPACT WEATHER POTENTIAL: INCREASING CONCERN FOR A POSSIBLE
WIDESPREAD SEVERE WEATHER EVENT ACROSS AT LEAST A PORTION OF
NORTHERN MICHIGAN.
DAMAGING WINDS AND ISOLATED TORNADOES APPEAR TO
BE THE MAIN THREATS...AND IT`S NOT IMPOSSIBLE THAT A LONG LIVED
SEVERE WIND EVENT MAY WORK THROUGH SOME AREAS.


PATTERN SYNOPSIS: QUITE AN ENERGETIC PATTERN TO START THE WORK
WEEK...WITH A PAIR OF SHORTWAVES RIDING ALONG THE NORTHERN TIER INTO
MONTANA/SOUTHERN CANADA TODAY RAPIDLY ADVANCING EAST AND DEEPENING
TONIGHT...ON THE HEELS OF A 60 KNOT MID LEVEL JET CORE CROSSING THE
NORTHERN ROCKIES. THAT FEATURE IS PROGGED TO RIDE THE NORTHERN U.S.
BORDER INTO MONDAY...DROPPING INTO THE NORTHERN LAKES MONDAY EVENING
BEFORE RAPIDLY DEPARTING AFTER 06Z TUESDAY. AT THE SURFACE...CLASSIC
LEE TROUGHING INTO THE CENTRAL/NORTHERN HIGH PLAINS WILL GET A BOOST
FROM THAT PASSING FEATURE...WITH A MODEST SURFACE RESPONSE EXPECTED
TO ADVANCE FROM NEAR THE NE/SD/IA/MN BORDER AT 12Z MONDAY INTO OUR
NECK OF THE WOODS BY MONDAY EVENING. THAT GENERAL SETUP WILL RATHER
QUICKLY LIFT A WARM FRONT INTO NORTHERN MICHIGAN MONDAY AFTERNOON...
DRAGGING IN A SIGNIFICANTLY WARMER AND MORE MOIST AIRMASS AND
HELPING SET THE STAGE FOR OUR POTENTIAL CONVECTIVE ISSUES. JUST AS
QUICKLY AS THE WARM FRONT ARRIVES...A COLD FRONT WILL CROSS THE
REGION LATE MONDAY EVENING...ALLOWING FOR BROAD WEAK LOW LEVEL
RIDGING TO ARRIVE IN ITS WAKE WITH QUIET WEATHER INTO MIDWEEK.

WELL...LET`S DIG RIGHT INTO IT. THIS SETUP REALLY DOES HAVE
POTENTIAL AND HONESTLY IS ONE OF THE BETTER POTENTIAL SETUPS WE HAVE
SEEN IN QUITE A FEW YEARS AROUND THESE PARTS. OF COURSE...WITH THAT
SAID...THERE REMAIN SOME BIG QUESTIONS...SPECIFICALLY REGARDING JUST
HOW FAR NORTH THE WARM FRONT WILL RETREAT...WHICH WILL HAVE A MAJOR
IMPACT ON HOW MUCH BOUNDARY LAYER MOISTURE AND INSTABILITY WE CAN
REALIZE. EVEN WITH THAT SAID...A METEOROLOGIST`S INTEREST IS ALWAYS
PIQUED WHEN A QUICK GLANCE AT CIPS SEVERE WEATHER ANALOGS SHOW THE
BEST MATCH BEING A FAIRLY HISTORIC EVENT FOR THE GREAT LAKES - THE
MAY 30-31 1998 SOUTHERN/CENTRAL MICHIGAN DERECHO AND SUBSEQUENT
TORNADOES ON THE NORTH SIDE OF THE BOW INTO NORTHERN LOWER.
FIRST AND
FOREMOST...WE WILL HAVE NO TROUBLE WITH DEEP LAYER AND LOW LEVEL
SHEAR...AS A PRONOUNCED 50-70 KNOT MID LEVEL JET CORE CRUISES
OVERHEAD INTO THE EVENING...OVERTOPPED WITH AN EVEN BETTER 80-90
KNOT UPPER JET STREAKING OVERHEAD. COUPLE THAT WITH LOCALIZED BACKED
FLOW IN THE VICINITY OF THE NORTHWARD ADVANCING WARM FRONT...AND
PROGGED 0-1KM/0-3KM HELICITY VALUES UPWARD OF 300 M2/S2 AND WE
CERTAINLY HAVE THE MAKINGS FOR SOME TROUBLE.

THE BIGGEST QUESTION IS OF COURSE CONVECTIVE EVOLUTION...AND TO WHAT
DEGREE ANY EARLY STORMS MONDAY MORNING WILL MAKE AN IMPACT. AT THE
MOMENT...IT WOULD APPEAR THAT ONE OR MORE MCS FEATURES WILL BE
ONGOING ACROSS SOUTHERN MN INTO IA FIRST THING MONDAY MORNING...
RIDING THE PERIPHERY OF VERY STEEP MID LEVEL LAPSE RATES/ELEVATED
MIXED LAYER/CAPPING POKING INTO THAT REGION...ALL WHILE A SECOND
BAND OF SHOWERS AND STORMS ARCS ALONG AN ELEVATED WARM FRONT/LOW
LEVEL JET/THETA-E NOSE FROM NORTHERN MN DOWN INTO PERHAPS THE
WESTERN U.P. DON`T FORESEE ANYTHING EXTENDING OVER THIS WAY THROUGH
MUCH OF THE MORNING AS OUR RELATIVE DRY AIR HANGS TOUGH...THOUGH
SUPPOSE A SHOWER OR TWO AREN`T OUT OF THE QUESTION NORTH OF M-68 AND
INTO EASTERN UPPER. NOW...HEADING THROUGH LATE MORNING AND THE
AFTERNOON...SHOULD SEE THE MID MISS VALLEY MCS DECAY AS IT RAPIDLY
PUNCHES INTO INCREASED CAPPING OVER IL...WITH STRONG HEATING GETTING
UNDERWAY IN THE DEVELOPING WARM SECTOR OUT INTO SOUTHERN WI AND
SOUTHEAST MN...WITH BOUNDARY LAYER DEW POINTS SURGING THROUGH THE
LOWER 70S AND SUBSEQUENT MLCAPE VALUES PUSHING 3000+ J/KG. CLOSER TO
HOME...SUSPECT WE ARE LOOKING AT A WARM ADVECTION WING OF SHOWERS
AND STORMS FIRING INTO THE AFTERNOON ALONG THE NORTHWARD LIFTING
WARM FRONT AND PRONOUNCED THETA-E AXIS. COULD WELL SEE SOME
SUPERCELLULAR STRUCTURES ALONG THIS BOUNDARY...AS MLCAPE VALUES
QUICKLY RISE ABOVE 1500 J/KG WITH PLENTIFUL SHEAR AND LOCALIZED
BACKED FLOW ALONG THE SURFACE BOUNDARY ITSELF. DEEP SHEAR VECTORS
ROUGHLY PARALLELING THE FRONT DO MAINLY ARGUE FOR SOME SORT OF A
NORTHWEST-SOUTHEAST LINEAR STRUCTURE...BUT THIS WILL BE OUR FIRST
SHOT AT SEVERE...INCLUDING PERHAPS AN ISOLATED TORNADO GIVEN LCL
HEIGHTS BELOW 1KFT AND AGAIN PLENTIFUL SHEAR. HAIL THREAT VERY LOW
WITH FREEZING LEVELS 12KFT AND ABOVE...OUTSIDE OF A VERY ORGANIZED
STORM.

ROUND TWO MAY COME INTO THE EVENING HOURS AS WE WAIT AND SEE JUST
HOW MUCH UPSTREAM ADDITIONAL ACTIVITY COMES TO LIFE. HAVE TO BELIEVE
THAT INCOMING HEIGHT FALLS WORKING ON THAT MUCH INSTABILITY WILL
HAVE NO TROUBLE LIGHTING UP CELLS AHEAD OF THE COLD FRONT OVER
WISCONSIN...WITH INITIAL DEEP SHEAR VECTORS AGAINST THE FRONT
SUGGESTING DISCRETE SUPERCELL STRUCTURES ARE LIKELY FOR A TIME.
HOWEVER...JUST ABOUT ALL HI-RES GUIDANCE CONTINUES TO POINT TOWARD
STORM/COLD POOL ORGANIZATION...WITH A LINEAR MCS FEATURE RAPIDLY
CROSSING INTO MICHIGAN. JUST HOW FAR NORTH THAT CONVECTIVE LINE GETS
REMAINS HIGHLY IN QUESTION...BUT BY THIS POINT...MOST IF NOT ALL OF
NORTHERN LOWER SHOULD BE WELL INTO THE WARM SECTOR...AND IT IS
INTERESTING TO NOTE THE SLIGHTLY FARTHER NORTH POSITION OF THE
DRIVING SHORTWAVE AS COMPARED TO THE MAY 30-31 EVENT. BASED ON
HISTORY OVER THE PAST 7 YEARS...IT WOULD SEE LIKELY THIS LINE WOULD
DIVE TOWARD THE BEST LAPSE RATES INTO SOUTHERN LOWER...BUT OF COURSE
STRONGLY ORGANIZED SYSTEMS OFTEN TAKE ON LIVES OF THEIR OWN. SIMPLY
PUT...WILL CONTINUE TO REALLY HIT THE SEVERE WEATHER THREAT HARD ON
SOCIAL MEDIA/WEB/ETC. AND WATCH REAL-TIME LATEST TRENDS AS WE GET
INTO MONDAY.

WOW...THAT WAS A LOT. GOOD THING THE REST OF THE PERIOD LOOKS RATHER
QUIET. LOW LEVEL RIDGING IS EXPECTED TO WORK EAST FROM THE PLAINS
INTO THE LOWER LAKES ON TUESDAY...AS THERMAL TROUGHING AND NOTABLY
DRIER AIR RUSH INTO THE NORTHERN LAKES DURING THE SAME PERIOD. THAT
SETUP FAVORS INCREASING AMOUNTS OF SUNSHINE AND A RETURN TO TYPICAL
NORTHERN MICHIGAN SUMMERTIME WEATHER - TEMPS INTO THE UPPER 60S/70S
AND COMFORTABLE HUMIDITY LEVELS. COULD SEE A TOUCH MORE CLOUD COVER
BY TUESDAY NIGHT INTO WEDNESDAY AS A VERY WEAK SHORTWAVE OR TWO
TRAVERSE THE OVERALL NORTHWEST FLOW REGIME INTO OUR AREA...BUT A
SEVERE LACK OF MOISTURE WILL PRECLUDE ANY PRECIP POTENTIAL...DESPITE
PHANTOM GUIDANCE ATTEMPTS TO SQUEEZE OUT A ROGUE SHOWER OR TWO AT
TIMES.

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18z 4km NAM fizzles the MCS tomorrow morning before it gets here then the strongest development occurs from Clinton to Sterling or so early evening. 

 

Via imagesf from Mike Hamernik, the RPM sustains the MCS into nrn IL quite well into mid morning but destabilizes plenty behind it with big time storms after 0z here. 

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AREA FORECAST DISCUSSION  

NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL  

337 PM CDT SUN JUN 21 2015  

 

   

SHORT TERM  

 

335 PM CDT  

 

THROUGH MONDAY NIGHT...  

 

VERY COMPLEX SCENARIO ON THE WAY REGARDING THE POTENTIAL FOR  

SEVERE WEATHER ON MONDAY.  

 

TONIGHT WILL BE MUGGY WITH LOWS IN THE 60S TO AROUND 70. STRONG  

SHORTWAVE TROUGH IN NORTHERN BRANCH OF UNSEASONABLY STRONG UPPER  

JET ACROSS NORTHERN TIER OF US WILL QUICKLY STRENGTHEN LOW  

PRESSURE CURRENT LOCATED OVER NORTHWEST HIGH PLAINS STATES.  

INTENSIFICATION OF SURFACE AND UPPER SYSTEM WILL RESULT IN RAPID  

RAMP UP IN SOUTHWESTERLY LOW LEVEL JET AND STRONG WARM ADVECTION  

COULD INITIATE SCATTERED CONVECTION SOUTHWEST OF CWA LATE TONIGHT  

THAT WOULD LIFT NORTHEAST INTO THE EARLY TO MID MORNING AND THEN  

CLEAR THE CWA BY MID DAY IN ONE OF THE POSSIBLE SCENARIOS FOR  

TOMORROW.  

 

OTHER SCENARIO IS FOR A SEVERE FORWARD PROPAGATING MCS TO FORM  

OVER THE DAKOTAS TONIGHT THAT COULD RIDE INTO THE AREA RIGHT  

AROUND MID-DAY...AND LIKELY BE A SEVERE WIND PRODUCER GIVEN  

PRSENCE OF 3000 TO 4000 J/KG OF MUCAPE IN PLACE AND 45 TO 60 KT OF  

0-6KM SHEAR AND 30-40 KT+ OF 0-3KM BULK SHEAR. THIS SCENARIO...AS  

DEPICTED BY ARW AND NMM EAST...AND TO A LESSER EXTENT 4KM NAM...IS  

SOMETHING TO CONSIDER THAT ADDS A LOT OF UNCERTAINTY TO THE  

FORECAST. HAVE GENERALLY KEPT POPS IN MID-HIGH CHANCE RANGE DURING  

POSSIBLE PERIOD OF MCS...AS IT IS ALSO POSSIBLE THAT STEERING  

FLOW/CORFIDI VECTORS TAKES THE LIKELY MCS NORTH OF OUR CWA. THIS  

IS WHAT IS SHOWN ON MANY OTHER MODELS INCLUDING 12KM  

NAM/GFS/ECMWF/GGEM.  

 

POSSIBLE MID DAY MCS COULD THROW A WRENCH IN REST OF FORECAST  

CONVECTIVE EVOLUTION ON MONDAY IN TERMS OF IMPACT ON  

INSTABILITY/CLOUDS AS WELL AS TEMPERATURES. SHOULD WE BE MISSED BY  

THE MCS...VERY STRONG EML WILL BE ADVECTED OVER THE AREA WITH 850  

MB TEMPS IN THE LOW 20S CELSIUS...WITH A STOUT CAP NOTED ON  

FORECAST SOUNDINGS THAT WILL MAKE FOR A WARM TO HOT AND HUMID AND  

WINDY AFTERNOON. STRONG PRESSURE FALLS DUE TO UNSEASONABLY STRONG  

SUB 1000 MB LOW IN NORTHERN LAKES WILL RESULT IN SOUTHERLY WINDS  

GUSTING UP TO 40 MPH AT TIMES. HAVE STAYED SOMEWHAT CONSERVATIVE  

WITH TEMPS...ESPECIALLY FARTHER NORTH...CONSIDERING UNCERTAINTY  

WITH MID-DAY CONVECTION...BUT IF WE STAY CAPPED MUCH OF THE  

AFTERNOON...THERMAL PROGS EASILY SUPPORT HIGHS IN THE 90S AREA  

WIDE. THIS WOULD ALSO SERVE TO BUILD INSTABILITY TO EXTREME LEVELS  

IN 4000-5000+ J/KG RANGE GIVEN DEWPOINTS IN LOW-MID 70S AND VERY  

STEEP NEARLY DRY-ADIABATIC MIDLEVEL LAPSE RATES. IN THE LATE  

AFTERNOON TO EARLY EVENING...COLD FRONT TRAILING FROM LOW TO THE  

NORTH WILL BE APPROACHING...IN ADDITION 60-70 KT 500 MB SPEED MAX  

PROVIDING UP TO 60 KT OF DEEP SHEAR WILL BE MOVING OVER THE AREA.  

FURTHERMORE...850 MB WINDS UP TO 50 KT WILL PROVIDE VERY STRONG  

LOW LEVEL SHEAR AND 0-3KM HELICITY OF 400-500 M2/S2.  

 

STILL A BIT OF UNCERTAINTY WITH RESPECT TO HOW WIDESPREAD THE CAP  

BREAKING IS WITH THE FRONT DURING THE LATE AFTERNOON AND EARLY  

EVENING. HOWEVER...MOST GUIDANCE HAS CONVERGED ON THIS OCCURRING.  

SO ANY THUNDERSTORMS THAT FORM IN IMPRESSIVE ENVIRONMENT WILL  

EASILY BECOME SEVERE...WITH A LIKELY SUPERCELLULAR STORM MODE AT  

LEAST INITIALLY DESPITE SFC WINDS STARTING TO VEER. THIS IS DUE TO  

DIRECTIONAL AND SPEED SHEAR FROM SOUTH-SOUTHWEST AT SFC TO WNW AT  

500 MB BEING MORE THAN SUFFICIENT FOR ROTATING UPDRAFTS. ALL  

SEVERE HAZARDS WILL BE POSSIBLE...INCLUDING LARGE HAIL...DAMAGING  

WINDS AND TORNADOES...ESPECIALLY AFTER INITIATION. HAVE MENTIONED  

ALL SEVERE HAZARDS IN GRIDS MONDAY EVENING. SPC HAS PLACED MOST  

OF AREA IN ENHANCED RISK FOR SEVERE WEATHER...AND INCLUDED 10% OR  

GREATER CHANCE OF SIGNIFICANT SEVERE WEATHER...WHICH SEEMS QUITE  

REASONABLE. FRONT WILL MOVE THROUGH THE AREA LATE IN THE EVENING  

AND END THE THREAT FOR SEVERE WEATHER. CANNOT FAIL TO MENTION  

THREAT FOR TORRENTIAL DOWNPOURS AND FLOODING AS WELL CONSIDERING  

THE ONGOING FLOODING ACROSS MANY AREAS...WITH PWAT VALUES IN 99TH  

PERCENTILE NEAR 2 INCHES.  

 

OVERALLL...CONFIDENCE IS LOW-MEDIUM IN CONVECTIVE EVOLUTION AND  

OVERALL FORECAST ON MONDAY. BUT CONFIDENCE IN SEVERE WEATHER  

OCCURRING SOMEWHERE IN CWA IS MEDIUM-HIGH...AS EVEN MID-DAY MCS  

THAT COULD POSSIBLY TEMPER EVENING SEVERE THREAT SOME WOULD LIKELY  

BE SEVERE FOR REASONS MENTIONED ABOVE. THE BOTTOM LINE  

IS...EVERYONE IN OUR REGION SHOULD STAY WEATHER AWARE TOMORROW AND  

HAVE A MEANS TO RECEIVE WARNINGS SHOULD THEY BE ISSUED.  

 

RC  

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I can't believe APX mentioned CIPS is showing "THE
MAY 30-31 1998 SOUTHERN/CENTRAL MICHIGAN DERECHO
" as the best analog. That was the biggest baddest storm I ever went through in my life, it hit at 6am here, with 80-90mph wind gusts for 5 minutes straight, lost lots of trees and power was out for 5 days I think it was.

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Just a thought....we may want to make a thread for tomorrow for severe...as it looks like there will still be bouts of severe and heavy rain throughout the week for this thread...BUT tomorrow looks like a "special" day...

 

CAll me superstitious, but I don't want to jinx anything by doing that...

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Just a thought....we may want to make a thread for tomorrow for severe...as it looks like there will still be bouts of severe and heavy rain throughout the week for this thread...BUT tomorrow looks like a "special" day...

 

 

I thought of that last night but was going to wait until we get an upgrade.  Plan is to split all the relevant posts from here into a new thread so that it won't be cluttered with stuff pertaining to the other days.

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Full on weenie (rightfully so) AFDs abound in the subforum...

@Powerball...then for archives sake, if tomorrow goes bullistic, then we ahould change the name of this one and make a new thread for the rest of the week

 

That sounds good to me.

 

It's up to Hoosier though.

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