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Derecho
07-29-2011, 09:20 AM
SPC has a large see text risk on the day three outlook for July 31. The write-up doesn't sound too hopeful.

...PARTS OF THE UPPER MISSISSIPPI VALLEY INTO THE GREAT LAKES...
A WEAK FRONT ADVANCING SOUTHWARD ACROSS THE REGION MAY PROVIDE THE
FOCUS FOR VIGOROUS STORMS SUNDAY. HOWEVER...MODELS SUGGEST THAT
MODERATE TO STRONG DESTABILIZATION MAY BE CONFINED TO IOWA...AND
CENTRAL/SOUTHERN WISCONSIN INTO NORTHERN ILLINOIS... WHERE MID/UPPER
FORCING FOR CONVECTIVE DEVELOPMENT REMAINS UNCERTAIN...AND
VARIABILITY EXISTS AMONG THE GUIDANCE CONCERNING CONVECTIVE
POTENTIAL.


The four to eight day outlook also mentions a storm risk. Without going into specifics attm, some of us on here have been closely monitoring early next week for possible rounds of severe weather in our area.

I'll post the entire four to eight day because it says so much... even though it details so little.


MEDIUM RANGE FORECAST GUIDANCE IS SUGGESTIVE THAT A SIGNIFICANT
IMPULSE EMERGING FROM THE MONSOONAL REGIME OVER THE INTERMOUNTAIN
WEST WILL TURN EASTWARD ALONG THE CENTRAL CANADIAN/U.S. BORDER AREA
EARLY NEXT WEEK...TO THE SOUTH OF A STRONG SHORT WAVE IMPULSE
ADVANCING WITHIN THE MAIN BELT OF WESTERLIES ACROSS THE CENTRAL
CANADIAN PROVINCES. FORCING ASSOCIATED WITH THIS FEATURE...AND
DOWNSTREAM LOW-LEVEL WARM ADVECTION...COULD PROVIDE THE SUPPORT FOR
ORGANIZED CONVECTIVE DEVELOPMENT ACROSS PARTS OF THE UPPER
MISSISSIPPI VALLEY/GREAT LAKES REGION ON MONDAY. THIS COULD THEN
CONTINUE ON WITHIN NORTHWESTERLY MID-LEVEL FLOW ON THE PERIPHERY OF
THE CENTRAL PLAINS SUBTROPICAL HIGH...ACROSS THE GREAT LAKES INTO
THE OHIO VALLEY BY LATE TUESDAY. WHILE IT IS POSSIBLE THAT
THERMODYNAMIC CONDITIONS COULD SET UP FAVORABLY FOR ONE LONG-LIVED
SIGNIFICANT MESOSCALE CONVECTIVE SYSTEM...TOO MUCH UNCERTAINTY
EXISTS AT THIS EXTENDED RANGE...PARTICULARLY GIVEN THE LIKELY WEAK
TO MODEST NATURE OF THE DEEP LAYER MEAN FLOW FIELDS. IT SEEMS MORE
LIKELY THAT THE CONVECTIVE POTENTIAL WILL BE MANIFESTED IN THE FORM
OF A FEW MORE MODERATE AND SMALLER CONVECTIVE CLUSTERS...ALTHOUGH
THESE COULD STILL BE ACCOMPANIED BY DAMAGING WINDS AND HAIL.


Disclaimer... Derecho storm threads have a high likelihood of jinxing any actual threat from occurring. :whistling:

Derecho
07-30-2011, 08:30 AM
SPC keeps the 06z day two confidence low


...UPPER MIDWEST INTO THE GREAT LAKES REGION...
THE WEAK SOUTHWARD ADVANCING FRONT MAY PROVIDE A FOCUS FOR VIGOROUS
STORM DEVELOPMENT SUNDAY. HOWEVER...BROADER SCALE MID-LEVEL HEIGHT
RISES COULD LIMIT THE COVERAGE OF ACTIVITY... PARTICULARLY WHERE
STRONGER BOUNDARY LAYER DESTABILIZATION IS ANTICIPATED...FROM PARTS
OF EASTERN SOUTH DAKOTA INTO WISCONSIN AND NORTHERN ILLINOIS.

Derecho
07-31-2011, 04:51 PM
Well today(Sunday) isn't looking like anything special. Shear has dropped off significantly and we've lost any substantial forcing. The SPC dropped the see text(5%) severe risk for SON, but Environment Canada is continuing a severe thunderstorm watch for central Ontario.

Looks like I jinxed it for today! ;)

Tomorrow looks like a write-off for any activity, so the focus shifts to Tuesday where we could be impacted by a mesoscale convective system sometime late Tuesday or early Wednesday. Probably a dying MCS if anything. :whistling:

Smokin Joe
07-31-2011, 05:28 PM
Thanks for the updates derecho...i think reverse phsycology works on the storm gods. When I started an official jinx thread for the 22-26 we had the f2 lol. Just say you are absolutely positive we won't get anything and watch the storms roll in!! :D

Derecho
07-31-2011, 09:15 PM
I lol'd


SEVERE WEATHER BULLETIN
ISSUED BY ENVIRONMENT CANADA
AT 9:30 PM EDT SUNDAY 31 JULY 2011.
---------------------------------------------------------------------
WATCHES/WARNINGS IN EFFECT FOR FAR NORTHERN ONTARIO...

SEVERE THUNDERSTORM WARNING FOR:
=NEW= MOOSONEE.

AT 9:27 PM EDT WEATHER RADAR AND LIGHTNING DETECTOR INDICATED
AN ISOLATED INTENSE THUNDERSTORM CAPABLE OF PRODUCING WIND
GUSTS UP TO 90 KM/H. THIS STORM IS LOCATED NEAR THE ABOVE
MENTIONED REGION AND IS MOVING SOUTHEAST AT 50 KM/H.

Derecho
07-31-2011, 09:18 PM
Thanks for the updates derecho...i think reverse phsycology works on the storm gods. When I started an official jinx thread for the 22-26 we had the f2 lol. Just say you are absolutely positive we won't get anything and watch the storms roll in!! :D

Well, not really making an attempt at reverse psychology -- but definitely playing the role of the down player -- as I usually do every storm event. :cool:

Just looking at Detroit radar right now, a small tstorm blew up over eastern Lake Huron and is currently making landfall near Port Albert moving ESE. Now that I've spotted it -- it's future remains in the balance... :unsure:

Edit: I have an unobstructed view of that particular storm as the sun is setting behind it. A very large anvil shape storm shape to my northwest extending way up on the horizon, I can even see flashes of light within the storm cloud. That's 96km away!

benjaminblizzard
08-01-2011, 12:02 AM
Looks like there are some pop ups heading toward me. Hopefully they won't peter out before they get here!

http://radblast-mi.wunderground.com/cgi-bin/radar/WUNIDS_map?station=BUF&brand=wui&num=1&delay=100&type=N0R&frame=0&scale=1.000&noclutter=0&t=1312172918&lat=0&lon=0&label=you&showstorms=99&map.x=400&map.y=240&centerx=400&centery=240&transx=0&transy=0&showlabels=1&severe=0&rainsnow=0&lightning=0&smooth=0

stormy kid
08-01-2011, 12:04 AM
Lol i've been seeing lightning in the sky for the past 2 hrs

Derecho
08-01-2011, 12:25 AM
That wee little storm thath I was watching to my northwest just plowed through KW with an amazing and intense lightning spectacular as well as with torrential rains.

EDIT: Just counted 200 lightning strikes in Waterloo Region on my USPLN feed. That translates to probably 250-350 strikes from that storm. Many strikes go undetected here because RoW is on the outer fringe of USPLN's range. That lightning show was wicked.

benjaminblizzard
08-01-2011, 12:48 AM
Wow, Derecho - that's awesome. I'm jealous!

EC has just posted a severe thunderstorm warning for Pickering-Oshawa-Southern Durham.

EDIT: Been seeing a fair bit of lightning, but just heard the first rumble in downtown TO.

Stormydude
08-01-2011, 12:50 AM
Good way to start August! Literally the first hour had a storm lol.

Derecho
08-01-2011, 12:58 AM
Good way to start August! Literally the first hour had a storm lol.


Yeah! It's like how 2011 opened with an EF3 tornado four minutes into the new year.

We sat in the back parking lot watching the storm approach for some 20 minutes. At first it was just a flash here and there thennpir of the blue just nonstop and rolling thuds of thunder! And look at that eh the storm
intensified before hitting KW then weakened after it passed. Is that a first? Haha

Raedwulf
08-01-2011, 01:04 AM
So I just witnessed some of the most amazing cloud structure in a storm that I haven't seen in years. It brought me back to my childhood when I first saw thunderstorms in the night.

You couldn't count a second between each flash of lightning..and all I could see was brilliantly tall spires of cumulonimbus clouds....just..beautiful

Derecho
08-01-2011, 01:07 AM
So I just witnessed some of the most amazing cloud structure in a storm that I haven't seen in years. It brought me back to my childhood when I first saw thunderstorms in the night.

You couldn't count a second between each flash of lightning..and all I could see was brilliantly tall spires of cumulonimbus clouds....just..beautiful

Oh man yeah as the storm approached here the structure was so strangley hypnotic with tall towers of almost bright blue clouds visible with each strike.

davefootball123
08-01-2011, 01:10 AM
Lots of lightning to my west with some anvil crawlers over me. I wouldnt say its the best lightning storm this year but it was a good one. Nothing like june 8th ;)


And Derecho the best part of the storm went through Ayr and that south of KW. But still im glad we all got something tonight eh

EDIT: Also I caught some photos and videos from the park near me so I will edit the files and cut the video and hopefully show you guys. Some of the shots are quite pleasing :)

EDIT2: I also want to note how the WRF-NMM, HRRR, and RUC predicted these storms to fire in this exact place and thats exactly what they did. Weird...August must be full of surprises.

Derecho
08-01-2011, 01:29 AM
EDIT2: I also want to note how the WRF-NMM, HRRR, and RUC predicted these storms to fire in this exact place and thats exactly what they did. Weird...August must be full of surprises.

yeah when I left for work at 1030 there was a large pocket of 3000j/kg mucape exactly where that KW rode through. From where that swath was, that storm
pretty much acted on target intensftying as soon as it hit it then weakening once it left it near Brantford. Good start to the month hopefully things stay interesting and exciting. The new day 2 should be out momentarily.

davefootball123
08-01-2011, 01:31 AM
Ya im kinda P O'd that the storm weakened but hey I got a good lightning show with some good shots. Just some light rain right now. I also love how a strom near Burlington is going against the mean storm direction.

Like they say. You win some you loose some. Well in this case I tied lol

EDIT: Some of the regulars on here are missing, like obwan and DarkSky. I wonder if they know that storms are out there tonight

davefootball123
08-01-2011, 01:42 AM
New Day 2 looks a little more favourable with that 30% added in. Nudge it a little east and im fine with it.

Stormydude
08-01-2011, 06:52 AM
Just looked at a picture of hail that fell in Ayr last night. The biggest look about dime size.

Smokin Joe
08-01-2011, 07:37 AM
Looks like a severe storm just rolled through sw ont sw of london. Hail 2.25 or so it said. Watch but no warning did this look better on radar than it was or was ec slow to the warning?

StormJunkie
08-01-2011, 08:03 AM
I`m still new at forecasting, but things look good for storms popping up along lake erie by buffalo and niagara. anyone concur?

Smokin Joe
08-01-2011, 11:40 AM
I looked at the hrrr earlier I think for 5 the composite reflectivity had something popping there see if it pans out not sure whatt the latest run says... Could be

Derecho
08-01-2011, 05:06 PM
If the latest SREF pans out -- tomorrow looks to be limited to a SWON special. The latest SPC Day 2 reflects today's SREF trends. Everything has shifted SW. Not holding my breath attm for tomorrow, but SPC indicates a moderate risk may be issued for Michigan.


...GREAT LAKES INTO UPPER OH VALLEY...
AN EXPANSIVE UPPER RIDGE WILL MAINTAIN CONTROL OF THE WEATHER OVER
THE CENTRAL UNITED STATES ON TUESDAY...WHILE SEVERAL WEAKER
DISTURBANCES ROTATE AROUND THE RIDGE FROM THE ROCKIES ACROSS THE
NORTHERN PLAINS...INTO THE NORTHEAST. WATER VAPOR IMAGERY SHOWS A
DISTINCT MID/UPPER LEVEL VORT MAX OVER WESTERN WY. THIS FEATURE
WILL BE MOVING INTO MN BY 02/12Z...AND IS FORECAST TO TRACK
SOUTHEASTWARD ACROSS THE GREAT LAKES REGION THROUGH THE FORECAST
PERIOD. THUNDERSTORMS WILL LIKELY BE ONGOING AHEAD OF THIS FEATURE
OVER MN/WI/UPPER MI TOMORROW MORNING. STRONG HEATING AND DEWPOINTS
IN THE UPPER 60S/LOWER 70S AHEAD OF THE STORMS WILL PROMOTE
INTENSIFICATION BY EARLY AFTERNOON AS STORMS TRACK INTO LOWER MI.
CURRENT PATTERN SUGGESTS THE POTENTIAL FOR A LONG-LIVED SEVERE MCS
TRACKING INTO NORTHERN OH AND WESTERN PA DURING THE EVENING.
DAMAGING WINDS APPEAR TO BE THE MAIN THREAT WITH THESE STORMS. AN
UPGRADE TO MODERATE RISK IS NOT OUT OF THE QUESTION AS THE EVENT
GETS CLOSER AND DETAILS BECOME MORE CLEAR.

Derecho
08-01-2011, 07:03 PM
Looks like a severe storm just rolled through sw ont sw of london. Hail 2.25 or so it said. Watch but no warning did this look better on radar than it was or was ec slow to the warning?

Environment Canada put a warning on her @<hidden> 820am for all of Elgin County (a little late imo). I posted pictures of the storm as viewed from 104km away here: http://ontariostorms.com/showthread.php?p=3467#post3467

------
Regarding tomorrow...

The latest DTX AFD only mentions 'moderate confidence in severe weather tomorrow' including a widespread event across Lower MI with wind and heavy rain as the main threat... but low confidence on timing. :whistling:

The latest CLE AFD makes no mention of severe weather tomorrow acorss NRN OH.

The latest BUF AFD is all over a potential for severe thunderstorms tomorrow, but models haven't agreed on a path so it's mostly all just speculation on effects for the BUF CWA... which basically the meteorologists are expecting a heavy rain event for WRN NY.

Excerpts from the BUF AFD

MAIN FEATURE DURING THIS PERIOD WILL BE A MAJOR MCS PROGGED BY ALL
MODELS TO DIVE SOUTHEAST ACROSS THE GREAT LAKES ON TUES NT. THIS
SHOWS UP AS A SFC LOW...WITH AN ALMOST "ALBERTA CLIPPER" TYPE PATH.
MODELS ARE STILL AT ODDS ON SPECIFIC PATH...WITH NAM/ECMWF TAKING
THE LOW SOUTHEAST ACROSS SW NY...WHILE 12Z GFS AND CMC MODELS TAKE
IT CLOSER TO CLEVE.

Hint, hint(northeast of London)
THIS WILL BE ESPECIALLY IMPORTANT AS AREAS TO THE WEST AND SOUTHWEST
OF THE TRACK WILL SEE AN INCREASED RISK OF SVR WX...WHILE AREAS JUST
E AND NE OF THE TRACK CAN BE LIABLE FOR HEAVY RAIN.

Hmm...
IT SHOULD
BE NOTED THAT MCS`S TEND TO DIVE MORE SOUTHEAST AND SOUTH THAN
ORIGINALLY EXPECTED...ESPECIALLY TWD DAYBREAK...SO A CLOSE MISS TO
THE WEST IS STILL POSSIBLE...BUT A STRIP OF 2+ INCH RAIN IS ALSO A
POSSIBILITY. WE MAY NOT KNOW WITH CONFIDENCE WHERE THE AXIS OF HEAVY
RAIN WILL BE UNTIL WE SEE IT VIA SATELLITE AND RADAR...MAYBE 3-6
HOURS AHEAD. STAY TUNED.

davefootball123
08-01-2011, 11:29 PM
I was looking at the SREF and GFS and I wouldnt count areas like London and that out for severe weather because conditions are somewhat favourable for this forecast MCS to hit them. 0-6km shear on the latest GFS is indicated at 40-60kts :O, however I think that may be slightly overdone. Anway, there is no doubt areas in Sarnia,Windsor and into SEMI will have a fun day tomorrow. Areas North and East of London will be looking at heavy rain tomorrow with some storms from about 9pm through early overnight.

Derecho
08-02-2011, 02:04 AM
New day one confirmed my worst fears... No SLIGHT northeast of London. In fact the spc has pulled the whole severe risk area westward. Judging by the latest model runs I'm not even holding out hope for severe thunderstorms in SWON. Probably just the rainshield hugging the centre area of low pressure as it crosses SON somewhere close to KW or GTA.

Derecho
08-02-2011, 07:23 AM
Looking at RUC, it's almost 8am and only 500j/kg MUCAPE exists across southern Essex County. 0-99j/kg covers the rest of us. Other parameters are also severely lacking. The sun is out now, but a large cloud deck from the ongoing MCS in Wisconsin is about to breach SON and should keep us cloudy all day. Pathetic looking start to the day for us. When the moisture surge arrives later this morning hopefully it can get us some where near 1,000j/kg.

Things are really starting to look like the SLGT may be pulled westward. SWON may end up in just a see text with the SLGT edging near Detroit or farther westward. Actually it's really starting to look like the MCS will develop way west into the Midwest and possibly even pass west of SEMI.

* Should be noted MUCAPE of 2,000-3,000j/kg already exists from Chicagoland eastward to Toledo and Cleveland, but anywhere north of Detroit including much of Lower MI and SON are void of any mucape.

davefootball123
08-02-2011, 10:23 AM
Ya the risk has definitely receeded west ward every model run. Oh well