Big Severe Wx Outbreak around 10/18/07 in Plains

[dtrain44]

True, true. This could get pretty wild......

[Ed Mahmoud]

The morning 12Z sounding from Norman already shows decent shear and instability

Thats actually kinda scary and there's been virtually no mixxing happening in the norman area

Did ya look at the hodograph?




Well, the storms to the West (already a bunch of warnings) may stabilize the atmosphere, although looks like most places South of I-20 are missing out now, so undisturbed unstable air shouldn't be too far away this afternoon, and if the current storms leave a boundary, well, wow!

[6SpeedTA95]

The morning 12Z sounding from Norman already shows decent shear and instability

Thats actually kinda scary and there's been virtually no mixxing happening in the norman area

Did ya look at the hodograph?




Well, the storms to the West (already a bunch of warnings) may stabilize the atmosphere, although looks like most places South of I-20 are missing out now, so undisturbed unstable air shouldn't be too far away this afternoon, and if the current storms leave a boundary, well, wow!

Hodograph is that dude in the top right, correct? If so I've never been too sure how to read those...can you give me a lesson?

[CrazyC83]

The morning 12Z sounding from Norman already shows decent shear and instability

Thats actually kinda scary and there's been virtually no mixxing happening in the norman area

Correct, it is mostly overcast in the western areas right now. The sun has been popping out in the central areas though...

Didn't the supercells come out of mostly cloudy skies on November 15, 2005 though?

[CrazyC83]

New MD - extends to southern Louisiana and extreme SE Texas, right to the Gulf:

MESOSCALE DISCUSSION 2091
NWS STORM PREDICTION CENTER NORMAN OK
0936 AM CDT WED OCT 17 2007

AREAS AFFECTED...FAR SERN TX...LA...SRN AR

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 171436Z - 171630Z

STORMS SHOULD INCREASE IN INTENSITY AND COVERAGE THROUGH THE DAY AND
A TORNADO WATCH MAY BECOME NECESSARY.

SURFACE ANALYSIS SHOWS AN EXTREMELY MOIST AIR MASS ADVECTING NWD OUT
OF THE WRN GULF OF MEXICO WITH DEWPOINTS IN THE MID TO UPPER 70S F.
A WEAK MESO LOW WAS NOTED AS WELL AND COULD BE SEEN ON VISIBLE
IMAGERY OVER SERN TX. VAD WIND PROFILES ACROSS LA WERE INDICATING
MODERATE LOW LEVEL SHEAR WITH 0-1 SRH VALUES OF 150-250 M2/S2.
HOWEVER...SOME WEAKNESS IN THE WIND FIELDS/HODOGRAPHS WAS NOTED IN
THE 2-4 KM LAYER.

OVER THE NEXT SEVERAL HOURS...AXIS OF LOW LEVEL
CONVERGENCE...PERSISTENT WARM/MOIST ADVECTION AND SOME POCKETS OF
HEATING SHOULD ALLOW FOR A GRADUAL INCREASE IN STORMS ACROSS SE
TX/LA AND SPREADING NWD INTO SRN AR. TORNADO THREAT WILL NOT BE HIGH
INITIALLY...BUT WILL INCREASE AS UPPER TROUGH APPROACHES FROM THE W.
AS THIS OCCURS...WIND FIELDS AT ALL LEVELS WILL INCREASE AND BECOME
MORE FAVORABLE FOR SUSTAINED UPDRAFTS AND SUPERCELLS WITH THREAT OF
TORNADOES.

..JEWELL.. 10/17/2007


ATTN...WFO...JAN...LIX...LZK...LCH...SHV...

29529435 32789431 33549371 33999310 34009219 33669133
32699129 30759174 29809213 29649259 29759331 29719376

[Weatherfreak14]

it sucks i have to go to work today, when i come back i should have plenty to track.

[CrazyC83]

I'm thinking they will jump to a HIGH at 1630Z, aimed at E OK/W AR. Also I think the MDT will be extended south (and maybe a bit north as well).

[6SpeedTA95]

I'm thinking they will jump to a HIGH at 1630Z, aimed at E OK/W AR. Also I think the MDT will be extended south (and maybe a bit north as well).

It could but the cloud cover is really holding down instability. May be just enough for them to restrain on the high.

[CrazyC83]

I'm thinking they will jump to a HIGH at 1630Z, aimed at E OK/W AR. Also I think the MDT will be extended south (and maybe a bit north as well).

It could but the cloud cover is really holding down instability. May be just enough for them to restrain on the high.

That's true, but the main threat seems to be many hours away though...I at least think the MDT will be enlarged into Louisiana and NE Texas, perhaps also up to the I-40 corridor in Missouri as well.

[artist]

maybe this should have gone in this thread -

I thought I would paste here what one of the resident mets had to say about this area this morning - he posted it with his tropical analysis (in that forum)he does each weekday morning for the tropics-

Closer to home, a MAJOR SEVERE WX OUTBREAK is set to
occur today in the OK/KS/MO/AR area. I forecasted
this 3 days earlier. There is a moderate risk in
these areas, with the possibility of EF2-EF5 in that
area of 10% within a 25 mile point, depicted as a
hatched area in the outlook map. This is better
explained in the SPC Convective Outlook Maps. This
area moves into the Great Lakes region tomorrow, and
another chance of Severe Wx exists Fri./Sat. as the
entire eastern 1/4 of the U.S. will be under a SLIGHT
risk area (Convective Outlook Map).

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

"Storm"

T. F. "STORM" WALSH III
GMCS, USCG (ret)
METEOROLOGIST/TROPICAL FORECASTER
MEMBER WEST CENTRAL FL AMS (webmaster)
CERTIFIED SKYWARN OFFICIAL STORM SPOTTER (advanced)

viewtopic.php?f=29&t=98349

[6SpeedTA95]

I'm thinking they will jump to a HIGH at 1630Z, aimed at E OK/W AR. Also I think the MDT will be extended south (and maybe a bit north as well).

It could but the cloud cover is really holding down instability. May be just enough for them to restrain on the high.

That's true, but the main threat seems to be many hours away though...I at least think the MDT will be enlarged into Louisiana and NE Texas, perhaps also up to the I-40 corridor in Missouri as well.

I think we could see them enlarge the MDT but the ongoing convection just west and north of OKC is really going to put a lid on future instability. The next sounding from norman will probably reflect this change.

[dtrain44]

Of course, the flip side of the ongoing convection is that it could leave some outflow boundaries to focus later development. The key issue will be how much time the atmosphere has to recover and recharge after these storms get out.....

It will still be another hour until the storms have even cleared I-40 and probably 12:30 or 1:00 at least before they're in KS. Lots of questions still abound.

[CrazyC83]

MESOSCALE DISCUSSION 2092
NWS STORM PREDICTION CENTER NORMAN OK
1024 AM CDT WED OCT 17 2007

AREAS AFFECTED...PARTS OF CNTRL/ERN OK INTO PARTS OF ERN KS AND
THE OZARK PLATEAU

CONCERNING...TORNADO WATCH 708...

VALID 171524Z - 171700Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 708 CONTINUES.

AN ADDITIONAL WW MAY BE NEEDED TO THE NORTH/EAST OF WW 708 SOON.

A COUPLE OF CLUSTERS OF THUNDERSTORMS ARE ONGOING...GENERALLY NEAR
AND SOUTHEAST OF THE INTERSTATE 35 CORRIDOR OF CENTRAL OKLAHOMA INTO
EASTERN KANSAS. ACTIVITY IS FOCUSED IN ZONE OF STRONGER LOWER/MID
TROPOSPHERIC WARM ADVECTION...BENEATH DIVERGENT UPPER FLOW
FIELD...DOWNSTREAM OF INTENSE MID/UPPER JET STREAK DIGGING INTO
PACIFIC COASTAL AREAS. THE DIGGING JET IS PROGGED TO SUPPORT
CONTINUED AMPLIFICATION AND AN INCREASING NEGATIVE TILT TO THE
SOUTHERN PLAINS UPPER TROUGH. AND...THE TENDENCY SHOULD BE FOR A
NORTH NORTHEASTWARD SHIFT TO THE STRONGER LARGE-SCALE FORCING FOR
UPWARD VERTICAL MOTION...TOWARD THE LOWER MISSOURI VALLEY.

THE EXPANSION AND CONSOLIDATION OF ONGOING CONVECTION INTO ONE LARGE
CONVECTIVE CLUSTER APPEARS LIKELY THROUGH MID AFTERNOON ACROSS NORTH
CENTRAL OKLAHOMA INTO EASTERN KANSAS. WHILE ACTIVITY FROM THE
SOUTHWESTERN-MOST CURRENT CLUSTER MAY TEND TO SPREAD ABOVE
RAIN-COOLED AIR MASS NOW OVER EASTERN KANSAS...THE CONVECTIVELY
GENERATED BOUNDARY NEAR THE EASTERN KANSAS/OKLAHOMA BORDER MAY BEGIN
TO LIFT NORTHWARD.

AND...DESPITE A TENDENCY TOWARD MID-LEVEL WARMING ACROSS THE OZARK
PLATEAU...THE BOUNDARY LAYER IS BEGINNING TO MOISTEN/DESTABILIZE IN
WAKE OF A SURFACE COLD WEDGE TO THE SOUTHEAST. SHEAR PROFILES ARE
ALREADY FAVORABLE FOR SUPERCELLS ACROSS SOUTHWEST MISSOURI/NORTHEAST
ARKANSAS...WHERE POTENTIAL FOR AT LEAST ISOLATED CONVECTIVE
DEVELOPMENT EXISTS TO THE SOUTH/EAST OF MAIN STORM CLUSTER.

..KERR.. 10/17/2007


ATTN...WFO...SGF...EAX...TSA...TOP...ICT...OUN...

35629790 37189747 38299745 39089633 39299457 38429316
36729332 35919396 35249468 34809644 34899783 35329796

[CrazyC83]

86 mph wind report from Kingfisher (via Mesonet)...

[6SpeedTA95]

Of course, the flip side of the ongoing convection is that it could leave some outflow boundaries to focus later development. The key issue will be how much time the atmosphere has to recover and recharge after these storms get out.....

It will still be another hour until the storms have even cleared I-40 and probably 12:30 or 1:00 at least before they're in KS. Lots of questions still abound.

Either way there will be severe weather the question now is will it be tornadic or wind/hail event.

[CrazyC83]

KOCO website reporting a tornado touchdown in Kingfisher...

[chadtm80]

http://www.storm2k.org/weather/hw3.php? ... rs_640x480

[6SpeedTA95]

Buddy of mine that works at NWS just passed this to me via AIM...

...POTENTIALLY SIGNIFICANT SEVERE WEATHER EPISODE POSSIBLE THIS AFTERNOON AND TONIGHT... WITH A THREAT FOR A FEW STRONG AND/OR... LONG-TRACK TORNADOES...

STRENGTHENING LOW AND DEEP-LYR WIND FIELDS ACROSS THE MDT AND SLGT RISK REGIONS WILL BE MORE THAN ADEQUATE FOR STRONG SUPERCELLS...
WITH DEEP SHEAR EXPECTED TO BE AOA 50 KTS OVER A BROAD SWATH FROM CNTRL/E TX NE INTO THE MID AND LWR MS VLYS THROUGH THE PERIOD.
WHILE RICHEST MARITIME AIR WILL REMAIN CONFINED TO REGION INVOF DISSIPATING FRONTAL ZONE OVER E TX/LA AND AR...SEASONABLY RICH
MOISTURE /WITH DEWPOINTS WELL INTO THE 60S/ WILL SURGE N BEYOND THE STL AREA BY EARLY THURSDAY AS 40-50 KT SSWLY LLJ BROADENS IN WARM
SECTOR OF DEEPENING SFC LOW. THE STEEPEST MID LVL LAPSE RATES...MEANWHILE...WILL SWEEP ENE FROM THE TX/OK PANHANDLE REGION THIS MORNING TO THE LWR MO VLY BY EVENING...ALONG AND N OF UPR JET.

GIVEN THE COMPLEXITIES POSED BY EXISTING CONVECTIVE CLUSTERS AND THE DISJOINTED/DIFFUSE NATURE OF SFC BOUNDARIES...IT IS DIFFICULT TO
CONFIDENTLY IDENTIFY A HIGH RISK CORRIDOR WITHIN THE BROAD AREAOUTLINED BY THE MDT/SGT RISK FORECASTS. PRESENT INDICATIONS ...HOWEVER...ARE THAT THE MOST SUBSTANTIAL SVR THREAT MAY DEVELOP THIS AFTN THROUGH EARLY TONIGHT FROM CNTRL/ERN OK NNE INTO SE KS...AS /1/ SFC HEATING.../2/ CONTINUED MOISTURE INFLOW...AND /3/ STRENGTHENING CONVERGENCE ALONG RESIDUAL OUTFLOW BOUNDARIES AND/OR TROUGH/DRY LINE SEGMENTS CREATE ENVIRONMENT FAVORABLE FOR STORM INITIATION. COMBINATION OF MODERATE INSTABILITY /1000-1250 J PER KG SBCAPE/ AND STRONG DEEP SHEAR SUGGESTS HIGH LIKELIHOOD FOR SUSTAINED SUPERCELLS. GIVEN BREADTH OF DESTABILIZING WARM SECTOR AND EXPECTED
DEGREE OF DIRECTIONAL SHEAR...THESE STORMS COULD YIELD STRONG AND/OR LONG-TRACK TORNADOES...IN ADDITION TO LARGE HAIL AND DAMAGING WIND.
THE SVR THREAT LIKELY WILL SPREAD INTO WRN/SRN MO AND NW AR EARLY TONIGHT...AND ERN MO/WRN IL EARLY THURSDAY...AS FORCING FOR ASCENT
IS MAXIMIZED AHEAD EJECTING UPR TROUGH.

[CrazyC83]

New watch:

SEL9

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 709
NWS STORM PREDICTION CENTER NORMAN OK
1045 AM CDT WED OCT 17 2007

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

NORTHWEST ARKANSAS
SOUTHEAST KANSAS
SOUTHWEST MISSOURI
NORTHEAST OKLAHOMA

EFFECTIVE THIS WEDNESDAY MORNING AND EVENING FROM 1045 AM UNTIL
600 PM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE
MILES EAST AND WEST OF A LINE FROM 55 MILES NORTHEAST OF CHANUTE
KANSAS TO 10 MILES SOUTH SOUTHEAST OF FORT SMITH ARKANSAS. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU9).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 708...

DISCUSSION...STRONG SYSTEM CONTINUES TO DEEPEN INTO PLAINS WITH
RAPID INCREASE IN MOISTURE/INSTABILITY NWD THROUGH WATCH AREA.
SEVERE THUNDERSTORMS NRN OK EXPECTED TO CONTINUE DEVELOPING NEWD
WITH INCREASING POTENTIAL FOR TORNADIC SUPERCELLS DURING THE
AFTERNOON.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 23040.


...HALES

[Ed Mahmoud]

New tornado watch corners OK/AR/KS/MO