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July 8-10 Severe Threat


Hoosier

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I have made it to Iowa today. I am going to guess that Iowa City, Davenport, and up to southwest Wisconsin will be where storms initiate tomorrow. I think there will be several hail/wind reports in southern Wisconsin, and continuing over to SW Michigan.  I may get a chance to follow one of the clusters across Illinois.

 

Looking at some of the hi-res models, I think there are several possibilities for severe storms across the region. The highest CAPE will be in Iowa and western Illinois. There will be some higher 0-3km helicity also in IA/western IL, but weaker helicity and 0-6km shear in other areas.

 

Here's an interesting one for you Wisconsin members: The 12z run of the 4km NAM shows a bow echo type shape in SW Wisconsin in the morning.

post-1182-0-01785800-1373336593_thumb.gi

 

 

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Wow, 4-6' of water on the Richmond Hill Line in Toronto. 1000 passengers had to be/or are still being rescued. Train has been stuck since 5:30.

 

---

 

Yeah Chinook, that seems to be the popular area for storms to fire this summer. DLL can attest to that! That area north of Dubuque is totally water logged.

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Well the environment in IA tomorrow will be conducive for tornadoes, just depends if things play out right and you get discrete convection at the right time. Pressures fall across the circled area in response to p-falls and you get great directional shear. Sky high PWATS tomorrow evening too.

 

 

 

 

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People still being pulled off that GO train in Toronto! ...6 hours after it got stuck.

 

An image from CP24.

 

 

250,000 customers without power atm.

 

Wow, in 1 hour at YYZ, 74 mm fell, which is the average July rainfall (74.4mm).

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Some nice decent lightning earlier with zero precipitation. Beautiful to sit outside atmosphere. Kinda itches me to go to the lake.

Regarding tomorrow, IMO we'll see how it shapes up in the next 6-8 hours. and the usual morning afternoon count down.

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Well the environment in IA tomorrow will be conducive for tornadoes, just depends if things play out right and you get discrete convection at the right time. Pressures fall across the circled area in response to p-falls and you get great directional shear. Sky high PWATS tomorrow evening too.

 

attachicon.gifUntitled.png

 

attachicon.gifnamCGP_con_pwat_027.gif

 

Wow that might be some of the highest theta-e and PWAT values I have ever seen modeled. Needless to say anything that forms in Iowa is going to come with a ton of water.

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Well the environment in IA tomorrow will be conducive for tornadoes, just depends if things play out right and you get discrete convection at the right time. Pressures fall across the circled area in response to p-falls and you get great directional shear. Sky high PWATS tomorrow evening too.

 

attachicon.gifUntitled.png

 

attachicon.gifnamCGP_con_pwat_027.gif

Heading out tomorrow Tsnow12? We're departing Peoria, IL for Waterloo, IA bout 10 AM

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30/30/5 on the new outlook.

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1241 AM CDT TUE JUL 09 2013

VALID 091200Z - 101200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER MS VALLEY/WRN GREAT LAKES SWWD INTO THE CNTRL PLAINS...

..SYNOPSIS

AN UPPER-LEVEL SHORTWAVE TROUGH LOCATED OVER THE NRN HIGH PLAINS EARLY THIS MORNING WILL DIG SEWD AND AMPLIFY AS IT ENTERS THE UPPER MS VALLEY LATER THIS EVENING...AND THEN PROGRESSES EWD TOWARD THE GREAT LAKES REGION DURING THE OVERNIGHT. AHEAD OF THE UPPER TROUGH...AN EML WILL SPREAD FROM THE CNTRL HIGH PLAINS ACROSS A VERY MOIST BOUNDARY LAYER AIRMASS OVER THE MIDWESTERN STATES. AS A COLD FRONT ADVANCES SEWD FROM THE NRN PLAINS INTO THE MS VALLEY AND CNTRL PLAINS DURING THE AFTERNOON...SEVERE THUNDERSTORM DEVELOPMENT WILL BE LIKELY.

..UPPER MS VALLEY/WRN GREAT LAKES SWWD INTO THE CENTRAL PLAINS

MCS LOCATED OVER THE WRN/CNTRL DAKOTAS EARLY THIS MORNING IS FORECAST TO ENTER PORTIONS OF MN BY MID MORNING. OTHER STORMS OCCURRING WITHIN WAA REGIME TIED TO A 30 KT LLJ WERE SPREADING E ACROSS THE CNTRL PLAINS...AND WILL LIKELY MOVE INTO ERN IA BY MIDDAY. A MIDLEVEL IMPULSE COINCIDENT WITH THE IA CONVECTION WILL MOVE ESEWD INTO LOWER MI AND THE MID OH VALLEY BY AFTERNOON...AND MAY AID IN AN ISOLATED SEVERE THREAT AS THE BOUNDARY LAYER DESTABILIZES. BEHIND THE DEPARTING MORNING STORMS...SWLY WINDS AT 850 MB WILL AID IN ADVECTING A WARM EML AIRMASS NEWD TOWARD THE MS VALLEY. RICH MOISTURE WITH SURFACE DEWPOINTS IN THE 70S/PW VALUES LOCALLY NEAR 2.0 INCHES IS FORECAST TO BE PRESENT FROM ERN NEB INTO SRN MN AND WRN IL. GIVEN MORNING CLOUDS/CONVECTIVE DEBRIS CLEARS THE AREA...STRONG HEATING WILL YIELD MLCAPE VALUES NEAR 3000 J/KG OVER MUCH OF THE REGION.

BY MID AFTERNOON...A COLD FRONT IS FORECAST TO BE LOCATED FROM NERN NEB INTO E-CNTRL MN. THIS FRONT WILL ACCELERATE SEWD DURING THE LATE AFTERNOON AND EVENING AS AN UPPER TROUGH DIGS FROM THE NRN PLAINS ACROSS THE UPPER MS VALLEY. FRONTAL FORCING COMBINED WITH THE VERY MOIST/UNSTABLE BOUNDARY LAYER WILL SUPPORT THE DEVELOPMENT OF THUNDERSTORMS. LOW-LEVEL SWLY FLOW WILL VEER TO WNWLY IN THE MIDLEVELS AS A 40-60 KT MIDLEVEL SPEED MAX SPREADS SEWD BEHIND THE FRONT. THIS WIND PROFILE COMBINED WITH THE VERY UNSTABLE ENVIRONMENT WILL FAVOR SUPERCELLS INITIALLY...WITH LARGE HAIL AND A COUPLE OF TORNADOES POSSIBLE. SEWD MOVING FRONT WILL LIKELY RESULT IN A QUICK TRANSITION TO A LINE WITH THE DOMINANT SEVERE THREAT EVOLVING TO DAMAGING WINDS.

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I completely agree with the SPC outlooks for day one, as a matter of fact, I was kind of perplexed by the afternoon day 2 outlook posted earlier on 07/08, based on the more consistent Euro output I thought the center line of the 30% risk area should run from DMX to Green Bay.  With the hatched hail risk overlaid with the 30% wind outlook I could see some wind driven 2" hail events.

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Assuming that complex moving into W MN doesn't screw things up (or the junk further south/east organizing), the 6z NAM is looking pretty robust across much of Central and Eastern IA from 18z-00z tomorrow afternoon/evening. I'm liking that Waterloo-Dubuque US 20 corridor for something, perhaps extending northward towards La Crosse later on.

 

That said, the 6z GFS and the SPC WRF seem to be in agreement on a further south solution.

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Uncertainty in the latest day 1 outlook.

 

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0747 AM CDT TUE JUL 09 2013

VALID 091300Z - 101200Z

...THERE IS A SLGT RISK OF SVR TSTMS THROUGH EARLY TONIGHT FOR THE
UPPER MS VALLEY TO ERN NEB AND NRN KS...

...MID-UPPER MS VALLEY TO ERN NEB/NRN KS THROUGH TONIGHT...
A COMPLICATED SCENARIO IS UNFOLDING THIS MORNING WITH ONGOING
CONVECTIVE CLUSTERS ACROSS MN/IA IN ASSOCIATION WITH A LEAD
SHORTWAVE TROUGH AND MCV. MEANWHILE...THE PRIMARY SYNOPTIC TROUGH
AND ASSOCIATED COLD FRONT ARE FARTHER BACK TO THE NW ACROSS THE
DAKOTAS/MT. IT APPEARS THAT THE ONGOING STORMS IN MN/IA WILL
PERSIST THROUGH THE DAY WHILE DEVELOPING EWD/SEWD ALONG THE PRIMARY
WARM FRONT THAT EXTENDS NW-SE FROM CENTRAL MN TO SRN WI. THE
CONVECTION WILL BE FED BY A MOIST BOUNDARY LAYER WITH 68-72 F
DEWPOINTS...AND RESULTANT MLCAPE OF 1500-2500 J/KG. HOWEVER...THE
STORMS WILL TEND TO OVERTURN THE RICHEST CORRIDOR OF LOW-LEVEL
MOISTURE RELATIVELY EARLY IN THE DAY ACROSS CENTRAL/SE MN...ERN
IA...SRN WI...AND NRN IL.

VERTICAL SHEAR IS NOT PARTICULARLY STRONG WITHIN THE UNSTABLE WARM
SECTOR IN ADVANCE OF THE STORMS THIS MORNING BASED ON VWP/S AND 12Z
SOUNDINGS. THUS...WHILE SOME DAMAGING GUSTS AND LARGE HAIL WILL BE
POSSIBLE WITH THE INITIAL STORMS...THIS EARLY CONVECTION COULD
DETRIMENTALLY IMPACT THE POTENTIAL FOR MORE SIGNIFICANT SEVERE
STORMS LATER THIS AFTERNOON AS THE PRIMARY SYNOPTIC WAVE AND COLD
FRONT MOVE SEWD ACROSS ERN SD AND MN INTO IA THIS EVENING. SOME
LOW-LEVEL RECOVERY IS MORE PROBABLE FARTHER S INTO ERN NEB/IA IN
CLOSER PROXIMITY TO THE LESS DISTURBED UPSTREAM WARM SECTOR...WHERE
THE MORNING CONVECTION IS LESS WIDESPREAD. HOWEVER...THIS AREA WILL
REMAIN A LITTLE S OF THE STRONGER DEEP-LAYER FLOW/VERTICAL
SHEAR...AND STORM COVERAGE ALONG THE COLD FRONT THIS EVENING IS A
BIT UNCLEAR.

THUS...WILL FOCUS THE RELATIVELY HIGHER PROBABILITIES IN ADVANCE OF
THE MORNING STORMS WHICH COULD INTENSIFY SOME BY MIDDAY/EARLY
AFTERNOON INTO WI...THOUGH WILL STILL ALLOW SOME POTENTIAL FOR
ADDITIONAL SEVERE STORM DEVELOPMENT ALONG THE COLD FRONT IN THE WAKE
OF THE MORNING STORMS. OVERALL...CONFIDENCE IN THIS FORECAST IS NOT
PARTICULARLY HIGH WITH RESPECT TO SEVERE STORM COVERAGE AND
CONVECTIVE MODE LATER THIS AFTERNOON INTO EARLY TONIGHT.

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Starting to look like a longer-ish duration soaker event for LOT....raises prospects for flash flooding and leaves severe potential limited...will have to see how unstable things get ahead of the lead wave comimg out of iowa....although it is already fairly shticky outside

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Up to 78/74 here. This summer pattern is a rise, wash, repeat type. I'd expect this ring of fire pattern to continue on and off into August.

 

Edit: Any new reports out of the GTA this morning?

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Edit: Any new reports out of the GTA this morning?

 

Things really weren't as bad as they could have been (all thing considered). Most of the floodwaters have drained away (particularly from highways) and people are moving again. Still might be some issues with the subways and GO trains but no serious injuries or deaths reported. The majority power has now been restored and crews are trying to fix some washouts and sinkholes.

 

Most serious incident was 1400 people stranded on this half submerged commuter train. Tracks were completely flooded over. All were rescued by boat without serious issues.

 

BOsDK-sCcAAXk2q.jpg

 

BOsLywtCEAEm4VF.jpg

 

BOsehpYCUAAON6V.jpg

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Up to 78/74 here. This summer pattern is a rise, wash, repeat type. I'd expect this ring of fire pattern to continue on and off into August.

 

Edit: Any new reports out of the GTA this morning?

 

Just your typical post-flash flood news. Minor injuries from yesterday, services being restored, people cleaning up. 126mm of rain fell in 2 hours. 121.4mm was the previous record during Hurricane Hazel. 

http://www.cbc.ca/news/canada/toronto/story/2013/07/09/toronto-rain-flooding-power-ttc.html

 

CP24 has a photo gallery up: http://www.cp24.com/massive-flooding-in-gta-1.1358947

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Assuming that complex moving into W MN doesn't screw things up (or the junk further south/east organizing), the 6z NAM is looking pretty robust across much of Central and Eastern IA from 18z-00z tomorrow afternoon/evening. I'm liking that Waterloo-Dubuque US 20 corridor for something, perhaps extending northward towards La Crosse later on.

 

That said, the 6z GFS and the SPC WRF seem to be in agreement on a further south solution.

 

Great work on my part... :axe:

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