Jump to content
  • Member Statistics

    17,603
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

June 13-16th Severe Weather Threat


Recommended Posts

21-

If the 0z NAM is a perfect prog then I wouldn't be shocked if we have a strong tornado in MO tomorrow..

Oh I would expect it if we realize something near the 00z NAM...

NAM really has a pooling of low level moisture in NW MO inside the surface low w.r.t. the GFS, hence the cap erosion and initiation across much of northern MO around 21-00Z. Seems reasonable given the focused low level convergence over the area--interested if SPC focuses more on northern MO tomorrow.

Link to comment
Share on other sites

  • Replies 242
  • Created
  • Last Reply

21-

NAM really has a pooling of low level moisture in NW MO inside the surface low w.r.t. the GFS, hence the cap erosion and initiation across much of northern MO around 21-00Z. Seems reasonable given the focused low level convergence over the area--interested if SPC focuses more on northern MO tomorrow.

Eh I guess the differences really are not that significant in terms of moisture--biggest difference is capping strength and timing of the greatest low level height falls/cap erosion. Thermals are a bit different too.

Link to comment
Share on other sites

Here's a little image I put together in IDV tonight. This is the supercell that formed in Cherry County, NE tonight which as Baro said formed on a easterly upslope convergence zone.

I have overlayed the radar data at the time it was producing a tornado, as well as the 10m winds in both vector and streamlines to show the convergence. Color shaded contour region is the SRH, with values starting at 25, and increasing by 25. The storm was in an environment of around 25-50 m2/s2. Tried to get current sfc data, but for some reason it kept on BSOD'ing (new word) my laptop, so I had to suffice with the latest 20km RUC data from 23Z. That being said, the vector, streamlines, and SRH are from the RUC, and then there is real time Level II data.

Link to comment
Share on other sites

Here's a little image I put together in IDV tonight. This is the supercell that formed in Cherry County, NE tonight which as Baro said formed on a easterly upslope convergence zone.

I have overlayed the radar data at the time it was producing a tornado, as well as the 10m winds in both vector and streamlines to show the convergence. Color shaded contour region is the SRH, with values starting at 25, and increasing by 25. The storm was in an environment of around 25-50 m2/s2. Tried to get current sfc data, but for some reason it kept on BSOD'ing (new word) my laptop, so I had to suffice with the latest 20km RUC data from 23Z. That being said, the vector, streamlines, and SRH are from the RUC, and then there is real time Level II data.

Wow nice job! Thanks for posting. I have a feeling the supercell itself was influencing the local wind fields because all data I looked at suggested a relatively weakly sheared environment (less than 35 kts effective bulk shear, less than 25-30 kts surface-6 km) with decent low level turning but rather unimpressive low level wind fields. Even the motion alone with increasing time would suggest that as it started out stationary then began to propagate S then SW.

Link to comment
Share on other sites

Things are going to light up over No. and central MO late this afternoon. Latest 12z GFS is now initiating just before 00z like the NAM and shows the potential for more discrete action along the warm front before things merge after 00z.

The 12z RUC was also breaking out discrete precip by 21z in southern IA/northern MO.

Link to comment
Share on other sites

The 12z RUC was also breaking out discrete precip by 21z in southern IA/northern MO.

I am a little surprised at how quiet this thread is. There is quite a bit of potential today. I would not be surprised if SPC upgrades something with one of the later updates today--whether that is the hatched outlooks or possibly a moderate later.

Link to comment
Share on other sites

I am a little surprised at how quiet this thread is. There is quite a bit of potential today. I would not be surprised if SPC upgrades something with one of the later updates today--whether that is the hatched outlooks or possibly a moderate later.

Ya agreed, The CoD team stayed in Syndey, NE last night and wasn't planning on chasing today due to the bad MO terrain but I told Sirvatka to reconsider and now they are chasing.

Link to comment
Share on other sites

Hey mods, you might want to add the 17th to this thread...off the 12z NAM for friday...a good mid-level westerly jet with a strong LLJ with ample intstablity and moisture to work with with small area of locally backed sfc flow creating very high 0-3 EHI numbers of around 10

The problem of having such a large area. I say go ahead and start a new thread mainly because we will be dealing with a new "system" with the transition to the west coast trough. Looks like there will be several severe weather bouts with this incoming trough and subsequent PV's ejecting around the base of that mean trough all the way from the high plains into the MS Valley.

Link to comment
Share on other sites

I am a little surprised at how quiet this thread is. There is quite a bit of potential today. I would not be surprised if SPC upgrades something with one of the later updates today--whether that is the hatched outlooks or possibly a moderate later.

Near/west of St. Louis looks to be pretty unstable with 50-60 knots of shear. Yesterday was a cap bust over by KC, but today there may be some supercells in the area near/west of St. Louis.

Link to comment
Share on other sites

You can see the pocket of differential CVA in Kansas that should help overcome the cap later this afternoon...

vadv.gif

Perfectly timed (or badly timed depending on which way you look at it) DCVA/Potential VA, also a late phase of the southern stream anomaly to the mean northern stream wave/trough. Looks to be some focused height falls and subsequent focused low level convergence over the capped region in response. There is not one 12Z piece of guidance that shows capping holding--and the clearing over the area is pretty obvious. This is a great time for an 18Z sounding--too bad there isn't really a suitable location across northern MO for one.

Link to comment
Share on other sites

With current satellite trends showing a Cu field in NW MO, major instability and shear, and the disturbance arriving late afternoon, I'd be not shocked at all to see something nasty along the IA/MO border or perhaps just S...right in radar lala land.

That was my exact thought when I saw this set up yesterday. Of course it would be in the radar hole.

Hi-res models continue to show some nasty supercells along the Highway 36 to I-70 corridor. The effective warm front is starting to make some serious progress northward, especially bulging out in the KMCI area (81 to 87 in the last hour).

Link to comment
Share on other sites

Perfectly timed (or badly timed depending on which way you look at it) DCVA/Potential VA, also a late phase of the southern stream anomaly to the mean northern stream wave/trough. Looks to be some focused height falls and subsequent focused low level convergence over the capped region in response. There is not one 12Z piece of guidance that shows capping holding--and the clearing over the area is pretty obvious. This is a great time for an 18Z sounding--too bad there isn't really a suitable location across northern MO for one.

Bigger issue today is going to be lack of a radar. That area (srn IA/nrn MO) has a lot of populated towns, and there is no excuse for the lack of radar coverage. I just hope it doesn't land us in a world of hurt.

Link to comment
Share on other sites

post-999-0-53131600-1308081342.gif

ACUS11 KWNS 141957

SWOMCD

SPC MCD 141956

ILZ000-MOZ000-IAZ000-KSZ000-142130-

MESOSCALE DISCUSSION 1218

NWS STORM PREDICTION CENTER NORMAN OK

0256 PM CDT TUE JUN 14 2011

AREAS AFFECTED...MUCH OF CNTRL...NRN AND ERN MO...FAR SRN IA...WRN

IL

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 141956Z - 142130Z

STORMS ARE EXPECTED TO INITIATE BY ABOUT 23Z OVER NRN MO/SRN

IA...THEN MOVE SEWD ACROSS NRN AND CNTRL MO AND EVENTUALLY WRN IL BY

LATE EVENING. VERY LARGE HAIL...DAMAGING WINDS...AND A FEW TORNADOES

ARE LIKELY.

SURFACE ANALYSIS SHOWS LOW PRESSURE OVER NERN KS AND SERN NEB...WITH

A COLD FRONT TRAILING SWWD. TO THE E...A MODIFYING OUTFLOW BOUNDARY

EXISTED ACROSS WRN MO...WHERE HEATING AND MIXING CONTINUES.

ALOFT...GRADUAL HEIGHT FALLS AND COOLING WILL CONTINUE AS A WEAK

UPPER SHORTWAVE TROUGH TRAVELS EWD ACROSS NEB/KS.

VISIBLE IMAGERY SHOWS BOUNDARY LAYER CU FROM NERN KS INTO THE MID MO

VALLEY NEAR THE LOW WITH DEWPOINTS RISING INTO THE UPPER 60S F.

HERE...CAPPING IS LESS WITH COOLER 700 MB TEMPS...AND THIS IS ALSO

TRUE EXTENDING SEWD ACROSS CNTRL MO AND TOWARD THE MS RIVER VALLEY.

MODELS ARE FAIRLY CONSISTENT WITH ERUPTING CONVECTION OVER NRN MO

AND SRN IA DURING THE 22-00Z TIME FRAME...WITH RAPID EXPANSION SEWD

DURING THE EVENING. DEEP LAYER SHEAR IS FAVORABLE FOR

SUPERCELLS...AND VERY LARGE DAMAGING HAIL WILL BE POSSIBLE. ALTHOUGH

NOT PARTICULARLY STRONG...LOW LEVEL SHEAR/VEERING WINDS WITH HEIGHT

WILL FAVOR ROTATION AND A FEW TORNADOES. STORMS MAY EVENTUALLY MERGE

AND FORM INTO A LARGER MCS WHICH WOULD TRAVEL SEWD INTO THE MS RIVER

VALLEY WITH A DAMAGING WIND THREAT.

Link to comment
Share on other sites

Not surprised there. Cu increasing pretty quickly now near Kansas City, with a lot of ACCAS growth to the east (indicating the lift is arriving as well as the mid level lapse rates are more than sufficient).

Yeah this looks explosive. One of these days where the "slight" is misleading since the potential prob wise and damage wise is much more significant than a slight with some hatched hail would indicate.

Link to comment
Share on other sites

Yeah this looks explosive. One of these days where the "slight" is misleading since the potential prob wise and damage wise is much more significant than a slight with some hatched hail would indicate.

I would find it hard to believe there is not a threat for a strong/perhaps very strong tornado in nrn MO/srn IA where the LCLs are lower and there should be excellent low-level shear. I would have gone 10 hatched for tornadoes myself if I were issuing the outlook.

Link to comment
Share on other sites

I would find it hard to believe there is not a threat for a strong/perhaps very strong tornado in nrn MO/srn IA where the LCLs are lower and there should be excellent low-level shear. I would have gone 10 hatched for tornadoes myself if I were issuing the outlook.

I tend to agree. Considering the strength of the surface winds (gusting around 25 kt) I'm surprised that the mesoanalysis is only showing 0-1 km shear around 15 kts. Although, this value should only go up as the LLJ begins to increase.

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...