Jump to content
  • Member Statistics

    17,609
    Total Members
    7,904
    Most Online
    NH8550
    Newest Member
    NH8550
    Joined

July 23-27 Severe Weather Threat


Recommended Posts

Not sure if this is too premature to start a thread for this weekend's severe threat in at least part of the subforum, but after reading the short term thread and this morning's SPC outlooks, here goes:

 

http://www.spc.noaa.gov/products/exper/day4-8/

DAY 4-8 CONVECTIVE OUTLOOK     NWS STORM PREDICTION CENTER NORMAN OK   0357 AM CDT TUE JUL 21 2015   VALID 241200Z - 291200Z   ...DISCUSSION...   PER 00Z/JULY 21 GUIDANCE CONSENSUS...IT SEEMS LIKELY THAT A   LOW-AMPLITUDE SHORTWAVE TROUGH IN THE NORTHERN STREAM WILL CONTINUE   TO AMPLIFY OVER THE INTERNATIONAL BORDER/UPPER MIDWEST ON DAY   4/FRIDAY...WITH A COLD FRONT SPREADING EAST-SOUTHEASTWARD ACROSS THE   UPPER MIDWEST/CORN BELT. WHILE THE POTENTIAL FOR A THURSDAY   NIGHT/EARLY FRIDAY MCS COMPLICATES SOME OF THE SPATIAL DETAILS...IT   IS PROBABLE THAT STRONG/SEVERE THUNDERSTORMS WILL REDEVELOP ACROSS   THE REGION FRIDAY AFTERNOON/EVENING AHEAD OF THE FRONT. SUFFICIENT   INSTABILITY/VERTICAL SHEAR IS EXPECTED TO BE IN PLACE FOR ORGANIZED   STORM MODES CAPABLE OF AT LEAST ISOLATED HAIL/WIND ACROSS MUCH OF WI   AND POSSIBLY EASTERN MN/NORTHERN IA.   FOR DAYS 5/6 SATURDAY AND SUNDAY...THE POTENTIAL FOR SOME   STRONG/SEVERE THUNDERSTORMS...MAINLY CAPABLE OF DAMAGING WINDS...IS   EXPECTED TO SPREAD EAST-SOUTHEASTWARD INTO PARTS OF THE MIDWEST/OH   RIVER VALLEY AND LOWER GREAT LAKES VICINITY AHEAD OF THE   EAST/SOUTHEASTWARD-ADVANCING COLD FRONT.   ..GUYER.. 07/21/2015

Also going to include Thursday in this thread in case the current D3 slight that includes far W MN gets pulled further east:

 

http://www.spc.noaa.gov/products/outlook/day3otlk.html

 DAY 3 CONVECTIVE OUTLOOK     NWS STORM PREDICTION CENTER NORMAN OK   0229 AM CDT TUE JUL 21 2015   VALID 231200Z - 241200Z   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE NORTHERN PLAINS...   ...THERE IS A MRGL RISK OF SVR TSTMS FROM THE NORTHERN ROCKIES TO   THE NORTHERN/CENTRAL PLAINS AND UPPER MIDWEST...   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE SOUTHEAST STATES...   ...SUMMARY...   SEVERE THUNDERSTORMS WILL BE POSSIBLE MAINLY ACROSS THE NORTHERN   PLAINS ON THURSDAY.   ...SYNOPSIS...   AN AMPLIFYING BELT OF WESTERLIES IS EXPECTED OVER THE NORTHERN THIRD   OF THE CONUS ON THURSDAY...WHILE AN UPPER RIDGE REMAINS CENTERED   OVER THE SOUTH-CENTRAL CONUS.   ...NORTHERN PLAINS AND NORTHERN ROCKIES TO CENTRAL PLAINS...   ONE OR MORE MID-LEVEL SHORTWAVE TROUGHS ARE EXPECTED TO CROSS THE   REGION...WITH DOWNSTREAM HEIGHT FALLS EXPECTED PARTICULARLY ACROSS   ND/NORTHERN SD INTO NORTHERN MN THURSDAY LATE AFTERNOON AND NIGHT. A   SURFACE LOW IS EXPECTED TO GRADUALLY DEEPEN ACROSS SD...WHILE A COLD   FRONT WILL MOVE EAST-SOUTHEASTWARD ACROSS THE REGION ON THURSDAY AND   SERVE AS A FOCUS FOR STRONG/SEVERE THUNDERSTORM DEVELOPMENT THURSDAY   AFTERNOON/EVENING...INITIALLY ACROSS PORTIONS OF ND/NORTHERN SD.   NEAR THIS FRONT...A MODERATELY UNSTABLE AIR MASS IS EXPECTED TO BE   COLLOCATED WITH AROUND 40 KT OF VERTICAL SHEAR...WHICH WILL BE   SUPPORTIVE OF SOME SUPERCELLS/WELL-SUSTAINED MULTICELLS CAPABLE OF   SEVERE HAIL/WIND AND POSSIBLY A TORNADO. MCS DEVELOPMENT SHOULD   SUBSEQUENTLY OCCUR THURSDAY EVENING...LIKELY SPREADING   EAST-SOUTHEASTWARD INTO WESTERN/NORTHERN MN DURING THE LATE   EVENING/OVERNIGHT HOURS.
Link to comment
Share on other sites

New D3 for Friday:

 

http://www.spc.noaa.gov/products/outlook/day3otlk.html

DAY 3 CONVECTIVE OUTLOOK     NWS STORM PREDICTION CENTER NORMAN OK   0230 AM CDT WED JUL 22 2015   VALID 241200Z - 251200Z   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE UPPER MIDWEST/UPPER   MS RIVER VALLEY...   ...THERE IS A MRGL RISK OF SVR TSTMS FROM THE CENTRAL HIGH PLAINS TO   THE UPPER GREAT LAKES...   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE SOUTHEAST STATES/FL   PENINSULA...   ...SUMMARY...   SEVERE THUNDERSTORMS WILL BE POSSIBLE FRIDAY MAINLY ACROSS PARTS OF   THE UPPER MIDWEST.   ...SYNOPSIS...   MODEST LARGE-SCALE PATTERN DEAMPLIFICATION IS EXPECTED ON FRIDAY AS   A LOW-AMPLITUDE BELT OF MODERATELY STRONG WESTERLIES WILL CONTINUE   TO PREVAIL OVER THE NORTHERN THIRD OF THE CONUS.   ...UPPER MIDWEST/UPPER MS RIVER VALLEY/CENTRAL PLAINS...   WEAK HEIGHT FALLS ARE EXPECTED OVER THE UPPER MIDWEST/INTERNATIONAL   BORDER VICINITY COINCIDENT WITH A CORRIDOR OF LOW-AMPLITUDE/NEARLY   ZONAL WESTERLIES. THUNDERSTORMS ARE EXPECTED TO INCREASE FRIDAY   AFTERNOON/EARLY EVENING NEAR A SOUTHEASTWARD-MOVING COLD FRONT   ACROSS PARTS OF MN AND NORTHERN/FAR WESTERN WI...AND POSSIBLY PARTS   OF THE MIDDLE MO VALLEY...ALTHOUGH CAPPING/MID-LEVEL WARMTH WILL   STEADILY INCREASE WITH SOUTHWESTWARD EXTENT ALONG THE ADVANCING   FRONT. BOUTS OF SEVERE WIND/HAIL WILL BE POSSIBLE WITH THE STRONGER   STORMS PARTICULARLY FRIDAY LATE AFTERNOON AND EVENING.

[ . . . ]

   ..GUYER.. 07/22/2015
Link to comment
Share on other sites

No risk area yet on the new D4-8 for Saturday and Sunday, although SPC not ruling out some severe for both days.  SPC also hinting at a possible risk in the Dakotas/Upper Midwest on Monday/Tuesday:

 

http://www.spc.noaa.gov/products/exper/day4-8/

DAY 4-8 CONVECTIVE OUTLOOK     NWS STORM PREDICTION CENTER NORMAN OK   0344 AM CDT WED JUL 22 2015   VALID 251200Z - 301200Z   ...DISCUSSION...   A LOW-AMPLITUDE/NEARLY ZONAL BELT OF WESTERLIES WILL GENERALLY   PREVAIL OVER THE NORTHERN TIER OF THE CONUS...WITH A COLD FRONT   EXPECTED TO SETTLE SOUTHEASTWARD ACROSS MUCH OF THE MIDWEST/GREAT   LAKES REGION THIS WEEKEND. ALTHOUGH LARGE-SCALE FORCING/VERTICAL   SHEAR SHOULD BE MODEST...AT LEAST SOME STRONG/SEVERE THUNDERSTORMS   WILL BE POSSIBLE ACROSS THE UPPER MS VALLEY/CORN BELT ON DAY   4/SATURDAY...AND INTO THE MIDWEST/GREAT LAKES ON DAY 5/SUNDAY.   A SOMEWHAT MORE SUBSTANTIAL UPPER TROUGH MAY BEGIN TO CROSS THE   NORTHERN CONUS/CANADIAN ROCKIES AROUND DAY 6/MONDAY. THE GENERAL   EAST-NORTHEASTWARD PROGRESSION OF THE UPPER TROUGH AND AN   INCREASINGLY MOIST DOWNSTREAM AIR MASS MAY LEAD TO A SEVERE RISK   ACROSS PARTS OF THE DAKOTAS/UPPER MIDWEST DURING DAYS 6/7   MONDAY/TUESDAY.   ..GUYER.. 07/22/2015
Link to comment
Share on other sites

What's not to love about the NAM?

 

This sounding... wtf? Am I really seeing this in late July, really?

 

This is almost certainly a convective response with the MCS the NAM is showing in that area and an overly deep surface low in the direct vicinity.

Link to comment
Share on other sites

Euro's really interesting for early next week... lots of instability

 

Problem with every day after Monday is the strongest flow aloft is severely lagging the effective warm sector due to the system's compact nature and the fact that it is occluding. Deep layer shear over most of the warm sector on Tues/Wed is pretty pitiful.

Link to comment
Share on other sites

Problem with every day after Monday is the strongest flow aloft is severely lagging the effective warm sector due to the system's compact nature and the fact that it is occluding. Deep layer shear over most of the warm sector on Tues/Wed is pretty pitiful.

Do you know how much shear there is on the Euro for Tuesday/Wednesday?

Link to comment
Share on other sites

Do you know how much shear there is on the Euro for Tuesday/Wednesday?

 

30 kts or less over most of that instability axis.

 

Yeah but 5500+ is still pretty rare.

 

Not really during summer.

 

The day I'd be watching is Monday further west.

Link to comment
Share on other sites

30 kts or less over most of that instability axis.

 

 

Not really during summer.

Don't need much to get an MCS going

 

Euro's showing highs well into the 90's widespread across Iowa, Minnesota and especially places further south. Looks like even triple digits for Minneapolis Metro. I'm about 15 miles north of Cincinnati and 90+ degree days are pretty rare and my average high for July is 88. I'm sure it's even more rare for Iowa and Minnesota to get that warm.

 

...and yes, I get that the surface temp isn't the only factor in instability. There's moisture (and thus LCL) and lapse rates.

 

MUCAPE climatology:

yB4dB2D.png

 

0y7x3VT.png

Link to comment
Share on other sites

Tornado Warning out in Wisconsin

 

 

 

TORNADO WARNING
WIC035-250430-
/O.NEW.KMPX.TO.W.0029.150725T0338Z-150725T0430Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1038 PM CDT FRI JUL 24 2015

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

* TORNADO WARNING FOR...
EASTERN EAU CLAIRE COUNTY IN WEST CENTRAL WISCONSIN...

* UNTIL 1130 PM CDT

* AT 1037 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A
TORNADO WAS LOCATED OVER LAKE WISSOTA...OR 8 MILES EAST OF EAU
CLAIRE...MOVING SOUTHEAST AT 35 MPH.

HAZARD...TORNADO.

SOURCE...RADAR INDICATED ROTATION.

IMPACT...FLYING DEBRIS WILL BE DANGEROUS TO THOSE CAUGHT WITHOUT
SHELTER. MOBILE HOMES WILL BE DAMAGED OR DESTROYED.
DAMAGE TO ROOFS...WINDOWS AND VEHICLES WILL OCCUR. TREE
DAMAGE IS LIKELY.

* THIS DANGEROUS STORM WILL BE NEAR...
FALL CREEK AROUND 1050 PM CDT.
AUGUSTA AROUND 1105 PM CDT.
FAIRCHILD AROUND 1120 PM CDT.

OTHER LOCATIONS IMPACTED BY THIS TORNADIC THUNDERSTORM INCLUDE
LUDINGTON AND LAKE EAU CLAIRE COUNTY PARK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

HEAVY RAINFALL MAY HIDE THIS TORNADO. DO NOT WAIT TO SEE OR HEAR THE
TORNADO. TAKE COVER NOW.

TORNADOES ARE EXTREMELY DIFFICULT TO SEE AND CONFIRM AT NIGHT. DO NOT
WAIT TO SEE OR HEAR THE TORNADO. TAKE COVER NOW.

TO REPORT SEVERE WEATHER CONTACT YOUR NEAREST LAW ENFORCEMENT AGENCY.
THEY WILL SEND YOUR REPORT TO THE NATIONAL WEATHER SERVICE OFFICE IN
THE TWIN CITIES.

&&

LAT...LON 4460 9122 4485 9138 4486 9137 4485 9109
4474 9092 4460 9092
TIME...MOT...LOC 0337Z 320DEG 31KT 4488 9127

TORNADO...RADAR INDICATED
HAIL...<.75IN

$

JPC
 
Link to comment
Share on other sites

For once, we have a cold front coming through at an ideal time of day with an opportunity for a fair amount of sunshine

 

But of course just about all of the other parameters for convection aren't very impressive. 

 

It would be nice to get something though.

Link to comment
Share on other sites

Sort of a low confidence scenario but could see storms develop almost overhead later, possibly along lake breeze.  Various models suggesting it.

 

I wasn't too excited about anything today, but the HRRR, RAP, and 4kNAM all showing storms firing along the breeze/front and drifting southeast. I might see some action before they fall apart after all.

Link to comment
Share on other sites

Storms starting to fire on the Lake Michigan lake breeze or whatever boundary may extend west to the Quad Cities region.  At least there might be something to watch this evening even if they don't become svr.  Models were correct.

 

 

Yeah, fired just south of me.  Boundary very well defined on KLOT.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...