May 19-22 Severe Weather Threat

[OntarioChaser]

Slight risk issued by EC for Monday.  Should be an interesting day.  Non-severe storms tomorrow as well.

[Central Illinois]

if i'm looking at this correctly the 12Z GFS has cape values between 2,000-4,000 and LI between -8 and -14 (I know this is somewhat overdone) for monday across parts of IA/IL/MO...is the thinking right now that the morning stuff out west will mess this up for monday afternoon? if i'm totally wrong on this please correct me I know more about winter storms then what i do severe thunderstorms 

[A-L-E-K]

wicked MCV getting going as plains action goes linear rather quickly...might complicate things tomorrow if long lived

[snowlover2]

New day 1

 

DAY 1 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0101 AM CDT SUN MAY 19 2013
  
   VALID 191200Z - 201200Z
  
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF KS/OK/MO AND
   SOUTHEAST NEB...
  
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE PLAINS TO UPPER
   MIDWEST/MIDDLE MS VALLEY...
  
   ...SYNOPSIS...
   ANOTHER RELATIVELY ACTIVE SEVERE WEATHER DAY IS EXPECTED ACROSS A
   BROAD PORTION OF THE PLAINS/MIDWEST TODAY AND TONIGHT. THE LEAD
   PORTION OF A PROMINENT UPPER TROUGH WILL SPREAD NORTHEASTWARD OVER
   THE CENTRAL PLAINS...WITH AN INCREASINGLY CLOSED UPPER LOW OVER THE
   NORTH-CENTRAL PLAINS/MIDDLE MO VALLEY BY TONIGHT. A CORRESPONDING
   SURFACE FRONTAL ZONE WILL SLOWLY SHIFT EASTWARD ACROSS KS/NEB/SD
   DURING THE PERIOD....WITH HEAT-AIDED SECONDARY SURFACE LOW
   DEVELOPMENT ANTICIPATED ACROSS SOUTHERN KS/WESTERN OK/NORTHWEST TX
   IN VICINITY OF A DRYLINE.
  
   ...PLAINS/OZARKS/MO VALLEY TO MIDDLE/UPPER MS VALLEY...
   A PLUME OF STEEP MID-LEVEL LAPSE RATES WILL REMAIN IN PLACE /AND-OR
   QUICKLY BE REESTABLISHED FROM SATURDAY PM CONVECTION/ ACROSS MOST OF
   THE CENTRAL/SOUTHERN PLAINS TO THE MIDDLE MS VALLEY. A RELATIVELY
   MOIST AIRMASS WITH MIDDLE/UPPER 60S AND SOME LOWER 70S F SURFACE
   DEWPOINTS WILL BE IN PLACE TODAY WITHIN THE WARM SECTOR TO THE EAST
   OF A NORTH-CENTRAL PLAINS COLD FRONT AND SOUTHERN PLAINS DRYLINE.
  
   AIDED BY A SUSTAINED LOW LEVEL JET/WARM ADVECTION...SCATTERED
   CONVECTION WILL LIKELY BE ONGOING EARLY TODAY ESPECIALLY ACROSS THE
   MIDDLE MO VALLEY AND UPPER MIDWEST. CONVECTIVE REMNANTS/OUTFLOW
   BOUNDARIES WILL BE A POTENTIAL FACTOR FOR
   REDEVELOPMENT/RE-INTENSIFICATION INTO THIS AFTERNOON FOR AREAS SUCH
   AS THE UPPER MIDWEST/UPPER MS VALLEY WITHIN A RELATIVELY
   MOIST/UNSTABLE AIRMASS ALONG/SOUTHWEST OF A NORTHWARD-SHIFTING WARM
   FRONT.
  
   SOUTH OF THE EARLY DAY/ONGOING ACTIVITY...STRONG HEATING/AGGRESSIVE
   DESTABILIZATION WILL TAKE PLACE ESPECIALLY FROM PARTS OF THE
   MIDDLE/LOWER MO VALLEY INCLUDING SOUTHEAST NEB/SOUTHERN IA
   SOUTH-SOUTHWESTWARD TO THE EAST OF THE DRYLINE ACROSS OK AND
   NORTH-CENTRAL/WEST-CENTRAL TX. HERE...MLCAPE VALUES ARE LIKELY TO
   EXCEED 3000 J/KG. AIDED BY STEADY HEIGHT FALLS AND AN INCREASING
   DEEP LAYER WIND FIELD /40-45 KT EFFECTIVE SHEAR/...SURFACE BASED
   TSTM/DISCRETE SUPERCELL DEVELOPMENT APPEARS MOST PROBABLE TO
   INITIALLY OCCUR ACROSS AREAS SUCH AS CENTRAL/NORTHEAST KS AND
   SOUTHEAST NEB INTO FAR NORTHERN OK...PERHAPS BY EARLY OR
   MID-AFTERNOON. FARTHER SOUTH...NEAR/SOUTH OF THE SURFACE
   LOW/FRONT/DRYLINE INDUCED TRIPLE POINT...SOMEWHAT MORE
   ISOLATED/HIGHER-BASED DEEP CONVECTIVE DEVELOPMENT IS ANTICIPATED BY
   LATE AFTERNOON/EARLY EVENING ACROSS CENTRAL/SOUTHERN OK SOUTHWARD
   INTO NORTH/WEST-CENTRAL TX.
  
   WITH AID OF A DIURNALLY STRONG SOUTH-SOUTHWESTERLY LOW LEVEL
   JET...FORECAST SHEAR PROFILES STRONGLY FAVOR LONG-LIVED SUPERCELLS
   CAPABLE OF VERY LARGE HAIL...IN ADDITION TO TORNADOES /PERHAPS ONE
   OR TWO STRONG/ ESPECIALLY WHERE DEWPOINTS HOLD IN THE UPPER
   60S/LOWER 70S. BY EARLY/MID-EVENING...THE PROXIMITY OF THE SLOWLY
   ADVANCING COLD FRONT AND BACKING MID-LEVEL FLOW SHOULD LEAD TO
   UPSCALE QUASI-LINEAR DEVELOPMENT AND AN INCREASING DAMAGING WIND
   THREAT ACROSS PARTS OF THE LOWER MO VALLEY/OZARKS AND MIDWEST.
   MEANWHILE...NEAR THE DRYLINE...A MORE DISCRETE MODE OF SUSTAINED
   SUPERCELLS /AGAIN SOMEWHAT HIGHER-BASED ESPECIALLY WITH SOUTHWARD
   EXTENT/ CAPABLE OF LARGE HAIL WILL BE THE PRIMARY CONCERN...BUT A
   LIMITED TORNADO THREAT AND SOME DAMAGING WIND POTENTIAL MAY EXIST AS
   WELL DURING THE LATE AFTERNOON AND EVENING HOURS.

 

 

[snowlover2]

New day 2

 

   DAY 2 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0100 AM CDT SUN MAY 19 2013
  
   VALID 201200Z - 211200Z
  
   ...THERE IS A MDT RISK OF SVR TSTMS FROM PARTS OF SERN KS/W CENTRAL
   AND SWRN MO SWWD INTO CENTRAL OK...
  
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER MS VALLEY/UPPER
   GREAT LAKES REGION SSWWD INTO N CENTRAL TX...
  
   ...SYNOPSIS...
   A LARGE UPPER LOW IS FORECAST TO LINGER IN PLACE ACROSS THE SD/NEB
   VICINITY...WHILE A MID-LEVEL JET STREAK AROUND THE SRN FRINGE OF THE
   LOW EJECTS FROM THE SRN ROCKIES INTO THE CENTRAL U.S. DURING THE
   PERIOD.  WHILE A SECOND LOW/TROUGH IS FORECAST TO APPROACH THE PAC
   NW COAST LATE...THE CENTRAL U.S. STORM SYSTEM WILL BE THE SYSTEM OF
   INTEREST WITH RESPECT TO SEVERE POTENTIAL ON MONDAY.
  
   AT THE SURFACE...A LOW IS FORECAST TO REMAIN OVER THE SD VICINITY
   BENEATH THE UPPER LOW...WITH A TRAILING COLD FRONT FORECAST TO SHIFT
   EWD ACROSS THE PLAINS.  AS THE AFOREMENTIONED JET STREAK SHIFTS INTO
   THE S CENTRAL PORTION OF THE COUNTRY...SECONDARY CYCLOGENESIS IS
   FORECAST TO OCCUR ALONG THE FRONT IN THE SWRN OK VICINITY...NEAR THE
   INTERSECTION OF THE FRONT AND A DEVELOPING DRYLINE.  THE COLD FRONT
   AND DRYLINE SHOULD SERVE AS PRIMARY FOCI FOR AFTERNOON DEVELOPMENT
   OF WIDESPREAD/SEVERE STORMS.
  
   ...UPPER MS VALLEY/UPPER GREAT LAKES SWWD INTO THE SRN PLAINS...
   WHILE DETAILS REMAIN DIFFICULT TO DISCERN DUE TO MULTIPLE ROUNDS OF
   WIDESPREAD/INTERVENING CONVECTION...ANOTHER SUBSTANTIAL SEVERE
   WEATHER EVENT IS FORECAST MONDAY/DAY 2 ACROSS THE CENTRAL CONUS.
  
   WEAKENING/DIMINISHING CONVECTION MAY BE ONGOING AHEAD OF THE FRONT
   ACROSS THE WARM SECTOR...BUT AS STORMS/CLOUDINESS WANE THROUGH THE
   MORNING IN MOST AREAS...EXPECT THE ONSET OF HEATING TO DRIVE STRONG
   AIRMASS DESTABILIZATION.  BY LATE AFTERNOON...THE
   PRE-FRONTAL/PRE-DRYLINE WARM SECTOR SHOULD FEATURE 2500 TO 3500 J/KG
   MIXED-LAYER CAPE.  AS LARGE-SCALE ASCENT -- AIDED BY THE APPROACHING
   JET STREAK AND FOCUSED ALONG LOW-LEVEL BOUNDARIES --
   INCREASES...EXPECT DEVELOPMENT/RAPID GROWTH OF INITIAL CONVECTION
   DURING THE MID AFTERNOON HOURS.  AS SHEAR INCREASES IN CONJUNCTION
   WITH INTENSIFYING FLOW ALOFT...STORMS SHOULD RAPIDLY ACQUIRE
   ROTATION -- PARTICULARLY WHERE CAPE/SHEAR JUXTAPOSITION APPEARS MOST
   FAVORABLE ACROSS THE MDT RISK AREA.  HERE...THREAT FOR VERY LARGE
   HAIL AND TORNADOES WILL EXIST.  THREAT FOR DAMAGING WINDS WILL
   INCREASE INTO THE EVENING...AS STORMS EVOLVE INTO LINEAR CLUSTERS IN
   SOME AREAS.  EVEN SO...ROTATING/SUPERCELL STORMS SHOULD LINGER
   LOCALLY WELL INTO THE EVENING HOURS -- WITH CONTINUED TORNADO AND
   LARGE HAIL POTENTIAL.  THREAT SHOULD FINALLY BEGIN TO DIMINISH
   OVERNIGHT...AS THE AIRMASS SLOWLY COOLS/STABILIZES -- PARTICULARLY
   ACROSS NRN PORTIONS OF THE RISK AREA.

 

 

[snowlover2]

New day 3

 

DAY 3 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0230 AM CDT SUN MAY 19 2013
  
   VALID 211200Z - 221200Z
  
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER GREAT LAKES
   REGION SWWD INTO CENTRAL TX...
  
   ...SYNOPSIS...
   SLIGHT WEAKENING/DEAMPLIFICATION OF THE LINGERING MID- AND
   UPPER-LEVEL STORM SYSTEM OVER THE CENTRAL U.S. IS FORECAST THIS
   PERIOD...AS A DIGGING/STRENGTHENING TROUGH/LOW SHIFTS SSEWD INTO THE
   WRN/NWRN U.S. THROUGH THE END OF THE PERIOD.  THE CENTRAL U.S.
   SYSTEM WILL REMAIN THE PRIMARY DRIVER FOR THE MAJORITY OF THE
   CONVECTIVE POTENTIAL THIS FORECAST.
  
   ...UPPER GREAT LAKES REGION SWWD INTO CENTRAL TX...
   MODEL DIFFERENCES WITH RESPECT TO TIMING OF A SHORT-WAVE TROUGH
   ROUNDING THE SRN PERIPHERY OF THE UPPER LOW AND WIDESPREAD
   CONVECTIVE ACTIVITY DURING INTERVENING DAYS IS YIELDING FAIRLY
   SUBSTANTIAL UNCERTAINTY WITH RESPECT TO DETAILS OF THE DAY 3
   /TUESDAY/ SEVERE WEATHER POTENTIAL STRETCHING FROM THE GREAT LAKES
   TO TX.
  
   ATTM...IT APPEARS THAT A COLD FRONT -- MOVING ACROSS THE CENTRAL AND
   SRN PLAINS AT THE START OF THE PERIOD -- SHOULD BEGIN TO WASH OUT AS
   EWD PROGRESSION SLOWS INTO THE AFTERNOON.  WHILE CLOUDS AND ONGOING
   SHOWERS AND THUNDERSTORMS AHEAD OF THE FRONT WILL LIKELY INHIBIT
   HEATING/DESTABILIZATION IN SOME AREAS INTO THE
   AFTERNOON...SUBSTANTIAL DESTABILIZATION IS FORECAST BY LATE
   AFTERNOON -- PARTICULARLY FROM THE SERN OK/WRN AR VICINITY SWWD INTO
   CENTRAL TX AHEAD OF THE DRYLINE. 
  
   BOUNDARY-LAYER CAPPING SHOULD LIMIT DEVELOPMENT INTO THE
   AFTERNOON...BUT STORM DEVELOPMENT IS EVENTUALLY EXPECTED -- WITH
   COVERAGE DEPENDING TO SOME DEGREE UPON TIMING OF A SHORT WAVE TROUGH
   CROSSING THE SRN ROCKIES DAY 2 AND THEN SHIFTING INTO TX DAY 3.
   WITH AMPLE SHEAR AND LIKELY-TO-BE STRONG INSTABILITY ACROSS THE
   ARKLATEX AND INTO CENTRAL TX...SIGNIFICANT SEVERE WEATHER --
   PRIMARILY VERY LARGE HAIL -- WILL BE POSSIBLE.  HOWEVER...WITH
   QUESTIONS REGARDING CONVECTIVE COVERAGE/CONCENTRATION...WILL
   INTRODUCE ONLY 15% SEVERE PROBABILITY ATTM.
  
   FARTHER N -- ACROSS MO AND AS FAR NEWD AS THE UPPER GREAT LAKES
   REGION...THE SCENARIO IS EVEN MORE UNCLEAR...AS MORE WIDESPREAD
   STORMS ONGOING EARLY IN THE PERIOD WILL LIKELY PERSIST THROUGH THE
   DAY.  THEREFORE...MORE UNCERTAIN DEGREE OF DESTABILIZATION -- AS
   WELL AS GENERALLY WEAKER SHEAR DUE TO MORE MERIDIONAL/UNIDIRECTIONAL
   FLOW ALOFT -- SHOULD LIMIT THREAT TO SOME DEGREE.  STILL...LOCALLY
   SEVERE STORMS CAPABLE OF PRODUCING HAIL AND DAMAGING WINDS AND
   POSSIBLY AN ISOLATED TORNADO CAN BE EXPECTED.  THREAT SHOULD
   DIMINISH OVERNIGHT...THOUGH STORMS/LIMITED POTENTIAL FOR SEVERE
   WEATHER WILL CONTINUE THROUGH THE END OF THE PERIOD.

 

[A-L-E-K]

threat looking pretty marginal

[Harry Perry]

Very marginal. Having a hard time finding a model that even paints ANY storms over Southern Lower Michigan.

[Stebo]

Very marginal. Having a hard time finding a model that even paints ANY storms over Southern Lower Michigan.

 

All the models paint storms across Michigan several times from Monday to Wednesday, the question is instability and whether the storms will be severe.

[wisconsinwx]

threat looking pretty marginal

 

Yet MKX seems pretty impressed about tomorrow at least.  Much of it comes down to how much crapvection hangs around.  If it comes through in the middle of the night, we may not have much problem heating up.  Of course, then there's also the question about how far north the warm sector reaches and if it avoids being shunted south by tonight's convection.

[Hoosier]

threat looking pretty marginal

Well, there's multiple shots at it even if the best stuff stays sw.

[Geos]

We got a little action near the Quad Cities right now. just west.

SEVERE WEATHER STATEMENTNATIONAL WEATHER SERVICE QUAD CITIES IA IL1224 PM CDT SUN MAY 19 2013IAC031-139-163-ILC131-161-191745-/O.CON.KDVN.SV.W.0020.000000T0000Z-130519T1745Z/SCOTT IA-MUSCATINE IA-CEDAR IA-MERCER IL-ROCK ISLAND IL-1224 PM CDT SUN MAY 19 2013...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR SOUTHWESTERNROCK ISLAND...NORTHWESTERN MERCER...EASTERN CEDAR...MUSCATINE ANDSOUTHWESTERN SCOTT COUNTIES UNTIL 1245 PM CDT...AT 1218 PM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR MUSCATINE...AND MOVING NORTHEAST AT 45 MPH.HAZARD...60 MPH WIND GUSTS AND NICKEL SIZE HAIL.SOURCE...RADAR INDICATED.IMPACT...EXPECT DAMAGE TO ROOFS...SIDING AND TREES.LOCATIONS IMPACTED INCLUDE...DURANT...MONTPELIER...ANDALUSIA...BUFFALO...WILTON...BLUE GRASS...ROCHESTER...BENNETT...CLARENCE...WILDCAT DEN STATE PARK...MIDWAYBEACH...MOSCOW...PLEASANT PRAIRIE...STOCKTON AND SUNBURY.

[snowlover2]

New day 2

 

  

DAY 2 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   1228 PM CDT SUN MAY 19 2013
  
   VALID 201200Z - 211200Z
  
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS OK...SERN KS...EXTREME
   NWRN AR...AND SWRN MO...
  
   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM
   SWRN TX TO THE UPPER GREAT LAKES...
  
   ...SOUTHERN PLAINS TO MID MS VALLEY...
  
   SECONDARY MID LEVEL SPEED MAX...ON THE ORDER OF 60KT AT 500 MB...IS
   EXPECTED TO EJECT ACROSS THE SRN ROCKIES INTO NRN OK BY 21/00Z.
   WHILE LATE DAY1 CONVECTION MAY DISTURB LOW LEVEL WIND FIELDS ACROSS
   PORTIONS OF SERN KS INTO MO...IT APPEARS LARGE SCALE INFLUENCE OF
   APPROACHING SPEED MAX SHOULD SHARPEN SYNOPTIC FRONT ACROSS OK BY
   PEAK HEATING.  THIS WILL BE THE PRIMARY FOCUS FOR RENEWED SEVERE
   THUNDERSTORM DEVELOPMENT ACROSS THE MDT RISK REGION.
  
   THUNDERSTORMS...A FEW SEVERE WITH A THREAT OF HAIL...MAY BE ONGOING
   AT THE BEGINNING OF THE PERIOD ACROSS SERN KS/MO ALONG THE NOSE OF
   VEERED LLJ.  THIS CONVECTION MAY TEMPORARILY DISPLACE THE SYNOPTIC
   FRONT OR PERHAPS EVEN PRODUCE OUTFLOW THAT BECOMES A FOCUS FOR
   AFTERNOON CONVECTIVE DEVELOPMENT.  STRONGEST BOUNDARY LAYER HEATING
   IS EXPECTED ACROSS WEST TX INTO SWRN OK WHERE SFC TEMPERATURES
   SHOULD SOAR INTO THE 90S.  ALONG/NORTH OF THE MAIN MID LEVEL JET
   CORE MID LEVEL TEMPERATURES SHOULD COOL SUCH THAT DEEP CONVECTION
   WILL EASILY DEVELOP ALONG AFOREMENTIONED CONVECTIVE OUTFLOW BOUNDARY
   INTO MO AND SHARPENING COLD FRONT/DRYLINE FARTHER WEST.  IN
   FACT...TSTMS MAY DEVELOP BY 20-21Z ACROSS OK WHERE SBCAPE IS
   EXPECTED TO BE IN EXCESS OF 3000 J/KG.  FORECAST DEEP LAYER
   SHEAR...IN EXCESS OF 50KT THROUGH 6KM...AND THE PROSPECT FOR A VERY
   MOIST WARM SECTOR FAVOR NUMEROUS SUPERCELL STRUCTURES...AT LEAST
   THROUGH MID EVENING OF THE CONVECTIVE CYCLE.  VERY LARGE HAIL AND
   TORNADOES ARE POSSIBLE WITH SUPERCELLS AND WITH TIME ONE OR MORE
   MCS/S SHOULD EVOLVE ALONG NOSE OF STRENGTHENING LLJ OVER OK.  AMPLE
   MID LEVEL FLOW WILL EXTEND ALONG THE DRYLINE INTO THE EDWARDS
   PLATEAU OF TX SUPPORTIVE OF ISOLATED SUPERCELL STRUCTURES CAPABLE OF
   PRODUCING AT LEAST LARGE HAIL AND DAMAGING WINDS.
  
  
   ...UPPER MS VALLEY/GREAT LAKES...
  
   LATEST MODEL GUIDANCE SUGGESTS A MID LEVEL SHORT WAVE TROUGH/SPEED
   MAX WILL ROTATE NEWD ACROSS IA/IL INTO MN/WI DURING THE AFTERNOON
   HOURS.  THIS FEATURE WILL SERVE TO INCREASE UVV ACROSS A FAIRLY
   MOIST/UNSTABLE BOUNDARY LAYER SOUTH OF SHARP WARM FRONT THAT WILL
   EXTEND FROM LOW NEAR THE ND/SD/MN BORDER...EWD INTO NRN WI AT PEAK
   HEATING.  WHILE SHORT WAVE TROUGH WILL INFLUENCE/SUPPORT DEEP
   CONVECTION...STRONG BOUNDARY LAYER HEATING WILL PROVE INSTRUMENTAL
   IN DESTABILIZATION ACROSS MN/WI AND SBCAPE COULD EASILY RISE TO NEAR
   2000 J/KG.  DISCRETE SUPERCELL STRUCTURES MAY EVOLVE WITHIN THIS
   AIRMASS AND WITH RELATIVELY LOW CLOUD BASES ISOLATED TORNADOES...IN
   ADDITION TO LARGE HAIL MAY BE OBSERVED.

 

[Central Illinois]

New day 2

DAY 2 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1228 PM CDT SUN MAY 19 2013

VALID 201200Z - 211200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS OK...SERN KS...EXTREME

NWRN AR...AND SWRN MO...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM

SWRN TX TO THE UPPER GREAT LAKES...

...SOUTHERN PLAINS TO MID MS VALLEY...

SECONDARY MID LEVEL SPEED MAX...ON THE ORDER OF 60KT AT 500 MB...IS

EXPECTED TO EJECT ACROSS THE SRN ROCKIES INTO NRN OK BY 21/00Z.

WHILE LATE DAY1 CONVECTION MAY DISTURB LOW LEVEL WIND FIELDS ACROSS

PORTIONS OF SERN KS INTO MO...IT APPEARS LARGE SCALE INFLUENCE OF

APPROACHING SPEED MAX SHOULD SHARPEN SYNOPTIC FRONT ACROSS OK BY

PEAK HEATING. THIS WILL BE THE PRIMARY FOCUS FOR RENEWED SEVERE

THUNDERSTORM DEVELOPMENT ACROSS THE MDT RISK REGION.

THUNDERSTORMS...A FEW SEVERE WITH A THREAT OF HAIL...MAY BE ONGOING

AT THE BEGINNING OF THE PERIOD ACROSS SERN KS/MO ALONG THE NOSE OF

VEERED LLJ. THIS CONVECTION MAY TEMPORARILY DISPLACE THE SYNOPTIC

FRONT OR PERHAPS EVEN PRODUCE OUTFLOW THAT BECOMES A FOCUS FOR

AFTERNOON CONVECTIVE DEVELOPMENT. STRONGEST BOUNDARY LAYER HEATING

IS EXPECTED ACROSS WEST TX INTO SWRN OK WHERE SFC TEMPERATURES

SHOULD SOAR INTO THE 90S. ALONG/NORTH OF THE MAIN MID LEVEL JET

CORE MID LEVEL TEMPERATURES SHOULD COOL SUCH THAT DEEP CONVECTION

WILL EASILY DEVELOP ALONG AFOREMENTIONED CONVECTIVE OUTFLOW BOUNDARY

INTO MO AND SHARPENING COLD FRONT/DRYLINE FARTHER WEST. IN

FACT...TSTMS MAY DEVELOP BY 20-21Z ACROSS OK WHERE SBCAPE IS

EXPECTED TO BE IN EXCESS OF 3000 J/KG. FORECAST DEEP LAYER

SHEAR...IN EXCESS OF 50KT THROUGH 6KM...AND THE PROSPECT FOR A VERY

MOIST WARM SECTOR FAVOR NUMEROUS SUPERCELL STRUCTURES...AT LEAST

THROUGH MID EVENING OF THE CONVECTIVE CYCLE. VERY LARGE HAIL AND

TORNADOES ARE POSSIBLE WITH SUPERCELLS AND WITH TIME ONE OR MORE

MCS/S SHOULD EVOLVE ALONG NOSE OF STRENGTHENING LLJ OVER OK. AMPLE

MID LEVEL FLOW WILL EXTEND ALONG THE DRYLINE INTO THE EDWARDS

PLATEAU OF TX SUPPORTIVE OF ISOLATED SUPERCELL STRUCTURES CAPABLE OF

PRODUCING AT LEAST LARGE HAIL AND DAMAGING WINDS.

...UPPER MS VALLEY/GREAT LAKES...

LATEST MODEL GUIDANCE SUGGESTS A MID LEVEL SHORT WAVE TROUGH/SPEED

MAX WILL ROTATE NEWD ACROSS IA/IL INTO MN/WI DURING THE AFTERNOON

HOURS. THIS FEATURE WILL SERVE TO INCREASE UVV ACROSS A FAIRLY

MOIST/UNSTABLE BOUNDARY LAYER SOUTH OF SHARP WARM FRONT THAT WILL

EXTEND FROM LOW NEAR THE ND/SD/MN BORDER...EWD INTO NRN WI AT PEAK

HEATING. WHILE SHORT WAVE TROUGH WILL INFLUENCE/SUPPORT DEEP

CONVECTION...STRONG BOUNDARY LAYER HEATING WILL PROVE INSTRUMENTAL

IN DESTABILIZATION ACROSS MN/WI AND SBCAPE COULD EASILY RISE TO NEAR

2000 J/KG. DISCRETE SUPERCELL STRUCTURES MAY EVOLVE WITHIN THIS

AIRMASS AND WITH RELATIVELY LOW CLOUD BASES ISOLATED TORNADOES...IN

ADDITION TO LARGE HAIL MAY BE OBSERVED.

hatched area getting in to parts of IL now.

Sent from my iPhone 5 using

Tapatalk!

[weathergy]

All the models paint storms across Michigan several times from Monday to Wednesday, the question is instability and whether the storms will be severe.

To be honest, I don't think instability will be a problem for Monday and Tuesday. I am more concerned about capping issues and the lack of decent shear.

[oldlogin]

New Tornado watch out

 

[Justin]

Cells in north central iowa and by marshalltown bear watching ...

Very soupy here now too... 85/71 slightly east of due south winds.

[frostfern]

I think Monday looks pretty good by SW Michigan standards.  If crapvection can stay away tomorrow morning CAPE will rise to 3000 J/KG.  The warm front and lake breeze will be a focal mechanism.  Coverage might be kind of spotty but anything that does form has a decent chance of becoming severe.

[frostfern]

To be honest, I don't think instability will be a problem for Monday and Tuesday. I am more concerned about capping issues and the lack of decent shear.

 

I think capping and low coverage will be the issue Monday.  Anything that does form could be strong though.  Tuesday has crapvection concerns in my area but it might be the better further SE.

[oldlogin]

BULLETIN - EAS ACTIVATION REQUESTED

TORNADO WARNING

NATIONAL WEATHER SERVICE LA CROSSE WI

303 PM CDT SUN MAY 19 2013

 

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

 

* TORNADO WARNING FOR...

  NORTHWESTERN FLOYD COUNTY IN NORTH CENTRAL IOWA...

  MITCHELL COUNTY IN NORTH CENTRAL IOWA...

 

* UNTIL 345 PM CDT

 

* AT 300 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A

  TORNADO WAS LOCATED NEAR NORA SPRINGS...AND MOVING NORTHEAST AT 40

  MPH.

 

  HAZARD...DEVELOPING TORNADO AND PING PONG BALL SIZE HAIL.

 

  SOURCE...RADAR INDICATED ROTATION.

 

 

* THIS DANGEROUS STORM WILL BE NEAR...

  OSAGE AROUND 320 PM CDT.

  STACYVILLE AROUND 335 PM CDT.

 

OTHER LOCATIONS IN THE WARNING INCLUDE ROCK CREEK...STATE ROAD 9 AND

COUNTY T 26...OSAGE SPRING PARK...HIGHWAY 18 AND COUNTY T 38...

MITCHELL...HIGHWAY 218 AND COUNTY T 40...LITTLE CEDAR...MEYER AND

BAILEY.

[Justin]

Just got put under tornado watch here... And that warned storm in north central iowa looking nasty. More storms going west of cedar rapids now...

[turtlehurricane]

Just had pea sized hail and 40-50 mph gusts, impressive storm to start off severe weather season. Hearing lots of sirens now unfortunately.

[daddylonglegs]

THose are just nasty by Mason City..

[wisconsinwx]

Just had pea sized hail and 40-50 mph gusts, impressive storm to start off severe weather season. Hearing lots of sirens now unfortunately.

 

Madison is the exciting weather event capital of the region I think.  Always get more winter storms and strong t'storms than here, that's for sure.  However, not quite severe criteria.  I'm sure there's a 60mph gust somewhere in that storm.

[Geos]

That t-storm complex rolling across S WI is about to bump into the stabilized air blowing in off the lake. Probably will start loosing its punch soon.

I can count out several outflow boundaries on this image.

 

[turtlehurricane]

That outflow boundary left behind over Wisconsin and northern Illinois from the MCS might help kick off tornadoes when the thunderstorms move in later. Another MCS approaching from the south with the bigger squall line off to the west. Southern Wisconsin is clearly in an MCS hot spot today.

[wisconsinwx]

Storm between Quad Cities and Galesburg looks like it is starting to bow and gain steam to the NE.  That one may be a threat if it keeps its NE movement, mostly through areas that saw plenty of sunshine and instability today.

[Stebo]

I actually like the potential tomorrow here locally, there will be a lot of boundaries to work with tomorrow and there certainly will not be a lacking of instability/shear tomorrow, if something pops it will go in a pretty big way in MI tomorrow. I actually think they might up the ante on the next SPC outlook tonight.

[RobertSul]

I actually like the potential tomorrow here locally, there will be a lot of boundaries to work with tomorrow and there certainly will not be a lacking of instability/shear tomorrow, if something pops it will go in a pretty big way in MI tomorrow. I actually think they might up the ante on the next SPC outlook tonight.

 

What would you go personally if you had to draw up the maps yourself?

[Stebo]

What would you go personally if you had to draw up the maps yourself?

5 tor/30wind/30hail the only caveat is if the MCS near KC keeps going through the night, the models have it falling apart overnight. If it falls apart it will lay down outflow boundaries and will have a MCV associated with it which will ignite storms tomorrow.