Jump to content
  • Member Statistics

    17,607
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

April 1st-4th Severe Weather Thread


andyhb

Recommended Posts

D4 area enlarged and shifted east a bit.

 

5ho8QkV.gif

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0400 AM CDT MON MAR 31 2014

VALID 031200Z - 081200Z

...DISCUSSION...
/DAY 4/

MODEL CONSENSUS IS THAT A VIGOROUS SHORTWAVE TROUGH WILL TAKE ON A
MORE NEGATIVE TILT AS IT EJECTS ENEWD THROUGH THE CNTRL/SRN PLAINS
INTO THE MID-LOWER MS VALLEY REGION THURSDAY...BUT SLIGHT TIMING
DIFFERENCES PERSIST. A MOIST WARM SECTOR WITH STEEP LAPSE RATES AND
MODERATE TO STRONG INSTABILITY WILL PRECEDE THIS FEATURE. FORCING
ALONG THE ATTENDANT COLD FRONT AND DRYLINE AND HEIGHT FALLS/ASCENT
IN WARM SECTOR WILL LIKELY CONTRIBUTE TO THUNDERSTORM INITIATION
FROM ERN OK THROUGH ERN TX. ACTIVITY WILL SUBSEQUENTLY DEVELOP EWD
THROUGH THE LOWER-MID MS VALLEY AND WRN TN VALLEYS WITHIN A STRONGLY
SHEARED ENVIRONMENT SUPPORTIVE OF SUPERCELLS AND ORGANIZED
LINES/BOWS.

/DAY 5/

SYSTEM WILL CONTINUE NEWD THROUGH THE TN AND OH VALLEYS WITH A
CONTINUED SEVERE THREAT...BUT THE LLJ AND STRONGER FORCING WILL TEND
TO LIFT NEWD AWAY FROM THE RICHER MOIST AXIS WITH TIME. WHILE A
SEVERE RISK AREA WILL LIKELY BE INCLUDED IN LATER OUTLOOKS FOR A
PORTION OF THE TN AND OH VALLEYS...TOO MUCH UNCERTAINTY EXISTS
REGARDING THE QUALITY OF THE THERMODYNAMIC ENVIRONMENT AT THIS TIME.


/DAY 6 AND BEYOND/

PREDICTABILITY DECREASES IN THIS TIME FRAME.

..DIAL.. 03/31/2014
Link to comment
Share on other sites

  • Replies 608
  • Created
  • Last Reply

Will be interesting to watch how the models handle the environment Weds evening, and if storms even form but one thing I noticed on the 12z NAM is it really strengthens the 850's across the eastern half of OK after 21z and even slightly backs them after 0z.

 

Thursday looks pretty darn impressive too on the NAM

Link to comment
Share on other sites

So is SGF joking when they mention CAPE in the 800-1500 J/kg range or what?

 

Yeah, I'm not sure where they got that. As a side note, the Springfield, MO radar is down due to equipment failure but it should be back up by Tuesday afternoon at the latest.

Link to comment
Share on other sites

Euro sticking to its guns on multiple discrete storms Wednesday afternoon and evening over OK and N TX (and later MO/AR overnight). There's still uncertainty regarding the low-level shear profiles, but I think this could be pretty significant. OKC and TUL would be under the gun, and possibly DFW depending on capping.

Link to comment
Share on other sites

Euro sticking to its guns on multiple discrete storms Wednesday afternoon and evening over OK and N TX (and later MO/AR overnight). There's still uncertainty regarding the low-level shear profiles, but I think this could be pretty significant. OKC and TUL would be under the gun, and possibly DFW depending on capping.

 

Do you think cells would be able to hold together into TUL with the potential CINH issues?

Link to comment
Share on other sites

Do you think cells would be able to hold together into TUL with the potential CINH issues?

 

It's always tough to judge whether a surface-based supercell threat will persist late into the night in these situations. Models indicate such a threat more often than it actually happens. In this case, taking the NAM for instance, CINH is negligible as late as 06z over E OK and W AR. The Euro is clearly signaling that discrete convection which begins in the late afternoon will persist through at least 06z and as far east as the heart of the Ozarks.

 

If convection initiates over the open warm sector well east of the dryline, as some guidance has indicated, then I'd definitely place TUL in a significant threat. If the dryline is the only zone of initiation, it's less likely that any surviving storms will still be truly surface-based by the time they arrive there.

Link to comment
Share on other sites

I have exams both Wednesday and Thursday, but stuff might actually be close enough to me Thursday for me to do a little chasing after I finish my exam at around 18Z. Some of the more recent model trends have been extending the severe threat further south into east Texas, which has me fairly excited.

 

As of right now, I'm thinking capping wins out over most of the warm sector on Wednesday, especially with the upper levels looking very meh. Thursday is looking much better in that regard. With more than ample instability and some good shear progged, the additional lift provided by upper jet dynamics might be just what is needed to erode away the cap enough to get a good number of discrete supercells going.

 

sped200f72.gif

Link to comment
Share on other sites

 

 

if dewpoints were only 5-7 degrees more today over MN and IA there would of been a decent outbreak right now in an arc of storms ..the sun came out and cold pocket overhead

 

still a couple of nicer low topped supercells with conformed tornadoes

 

PRELIMINARY LOCAL STORM REPORT  

NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN  

440 PM CDT MON MAR 31 2014  

   

.TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON  

   

.DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.  

 

..REMARKS..  

 

0408 PM TORNADO 3 SE ST LEO 44.69N 96.01W  

03/31/2014 YELLOW MEDICINE MN LAW ENFORCEMENT  

 

STRUCTURAL DAMAGE REPORTED WITH PROBABLE TORNADO  

SOUTHEAST OF ST LEO. TIME ESTIMATED.  

 

0410 PM TORNADO 2 ESE ST LEO 44.71N 96.02W  

03/31/2014 YELLOW MEDICINE MN LAW ENFORCEMENT  

 

DAMAGE REPORTED...EXTENT UNKNOWN. TIME ESTIMATED.  

 

Link to comment
Share on other sites

FWD doesn't seem to be as excited about this system now as they were before. Cap issues through Wednesday and Thursday the system looks to move through too early in the day at least for DFW and are concerned about cap on Thursday as well. Maybe things will change and this dryline will slow down Thursday or Wednesday will surprise. My first spring season here so was all excited as I heard the last couple years have been pretty quiet.

Link to comment
Share on other sites

FWD doesn't seem to be as excited about this system now as they were before. Cap issues through Wednesday and Thursday the system looks to move through too early in the day at least for DFW and are concerned about cap on Thursday as well. Maybe things will change and this dryline will slow down Thursday or Wednesday will surprise. My first spring season here so was all excited as I heard the last couple years have been pretty quiet.

 

The last two years have featured significant events in the DFW metroplex. First it was (oddly) April 3rd, 2012 and then May 15th, 2013, which had the first violent tornado in N TX (Granbury/De Cordova) since 1994.

Link to comment
Share on other sites

The last two years have featured significant events in the DFW metroplex. First it was (oddly) April 3rd, 2012 and then May 15th, 2013, which had the first violent tornado in N TX (Granbury/De Cordova) since 1994.

 

Both of those events were also somewhat surprise events, as they were both only slight risk days but ended up overachieving. They also were both days I almost decided to chase last minute but for one reason or another didn't quite pull the trigger. I'm still kicking myself a bit for missing the May 15th event last year.

Link to comment
Share on other sites

On a historical note, the setup especially at 500 mb on Thursday is really reminding me of November 25th, 1926, which was the deadliest November outbreak in US history and hit AR very hard, including an F4 through Heber Springs that caused at least 20 fatalities. Below is the 500 mb pattern that day @ 18z and 00z.

krUX55e.gif

YzFjLIT.gif

Link to comment
Share on other sites

The last two years have featured significant events in the DFW metroplex. First it was (oddly) April 3rd, 2012 and then May 15th, 2013, which had the first violent tornado in N TX (Granbury/De Cordova) since 1994.

Well the folks I talked to love this time of year so maybe they are expecting them all the time or comparing to above normal years :) I have noticed down here that not every forecast is set in stone and can change, less predictability down here compared to up north. Heck, I am still trying to understand a cap and dryline. Thursday is still a few days away and the way models are, I am sure it will change some more.

Link to comment
Share on other sites

I was just about to quote Brett's post but it was deleted so fast because there wasn't a comparison of 1926 to 2014. At first I was going to say the same thing until I realized its just 6 hours difference, not 88 or so years lol.

 

Haha, guilty as charged. I'm an idiot. "Wow I've never seen a better analog in my life!" :axe:

Link to comment
Share on other sites

We both thought that one of the two H5 maps you posted was a model forecast for tomorrow, which would've made it the greatest analog match in the history of mankind.

 

Oh, lol. I see.

 

Well is rather disconcerting that a setup that produced a major tornado outbreak with over 100 fatalities in November is a close match considering we are going to have much stronger thermodynamics in place on Thursday in all likelihood than a November setup.

Link to comment
Share on other sites

And...the GFS is holding generally for Thursday, the size of the warm sector with 2000-3000+ J/kg SBCAPE there at 21z is just something else. Some May-like theta-e advection going on there.

 

Edit: I did notice some issues with the VWP in AR later on through the evening, with backing in the 700 mb level, so we'll have to see if that becomes more prominent, the southern half of MO still looks like full steam ahead though.

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...