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

[dtrain44]

Finished my undergrad in 2005 and will finish my M.A. in international relations in the spring. I'll be headed to law school next year.....sad, I know

When and what did you study?

The wind is howling here as well. Folks here at work are looking at the skies and are scared (shoot, you'd think there was a tornado coming now). Probably a good thing, though: keeps folks tuned in......

[6SpeedTA95]

It's clearing up here.

[6SpeedTA95]

Finished my undergrad in 2005 and will finish my M.A. in international relations in the spring. I'll be headed to law school next year.....sad, I know

When and what did you study?

The wind is howling here as well. Folks here at work are looking at the skies and are scared (shoot, you'd think there was a tornado coming now). Probably a good thing, though: keeps folks tuned in......

BA in MIS, graduated in 2005

Working on my masters now but not at OU

[JonathanBelles]

Ill be in the chatroom most of the day if anyone wants to come over.

Note to Core: change the chat topic, its not sports2k anymore...

[CrazyC83]

Is it just me or do I see a QUADRUPLE-point situation setting up? (warm front, cold front, trough, dryline)

[JonathanBelles]

Is it just me or do I see a QUADRUPLE-point situation setting up? (warm front, cold front, trough, dryline)

Ingredients are perfect.... http://www.hpc.ncep.noaa.gov/sfc/90fwbg.gif

[Ed Mahmoud]

My guess (being Texocentric due to living here) that the line West of DFW is their shot for severe. Abilene and Childress have gone to SW winds, but dew points not dropping yet, which would seem to suggest dry line isn't as sharp as it could be.

IR loop

Edit 'there' to 'their'. Homonysm are not my friend.

[CrazyC83]

Day 2 updated; virtually unchanged.

[CrazyC83]

SPC AC 171707

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1207 PM CDT WED OCT 17 2007

VALID 181200Z - 191200Z

...THERE IS A MDT RISK OF SVR TSTMS FROM THE OH RIVER IN NRN
KY...NWD INTO SERN WI AND LOWER MI...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM
THE CNTRL GULF COAST TO THE ERN U.P. OF MI...

...SYNOPSIS...

DEEPENING OF CENTRAL U.S. LOW PRESSURE SYSTEM DURING THE DAY1/DAY2
TIME PERIOD WILL ENHANCE THE PROSPECT FOR POTENTIALLY SIGNIFICANT
SEVERE WEATHER ALONG AND JUST EAST OF THE MS VALLEY
REGION...ESPECIALLY THAT REGION FROM IL/IND NWD INTO SERN WI/SWRN
LOWER MI THURSDAY. DAMAGING WINDS AND TORNADOES APPEAR TO BE THE
MAIN SEVERE WEATHER THREATS ACROSS THE MODERATE RISK AREA.

...MID MS/OH VALLEY...GREAT LAKES...

EARLY MORNING MODEL GUIDANCE CONTINUES EARLIER TRENDS OF DEEPENING
CNTRL PLAINS SFC CYCLONE LATE DAY1 OVER ERN NEB. SFC LOW SHOULD
LIFT FROM NEAR OMA NEWD INTO NWRN WI BY 18/12Z AS COLD FRONT SWEEPS
ACROSS THE MS VALLEY. INTENSE MID LEVEL HEIGHT FALLS...ON THE ORDER
OF 150-180M...AND ASSOCIATED LARGE SCALE ASCENT WILL SPREAD FROM
IA/IL NEWD INTO THE GREAT LAKES DURING THE DAYLIGHT HOURS AS SPEED
MAX TRANSLATES FROM SRN MO INTO LOWER MI. NEEDLESS TO
SAY...VERTICAL SHEAR PROFILES WILL BECOME QUITE FAVORABLE FOR
ORGANIZED...FAST-MOVING SEVERE THUNDERSTORMS.

LATEST THINKING IS SEVERE THUNDERSTORMS WILL BE ONGOING AT THE
BEGINNING OF THE PERIOD ARCING AHEAD OF THE FRONT FROM IA...IL INTO
WRN KY. FORECAST SOUNDINGS ACROSS THIS REGION SUGGEST CONVECTIVE
UPDRAFTS WILL BE MODULATED BY INTENSE SHEAR/FORCING WITHIN A WEAK
LAPSE RATE/INSTABILITY ENVIRONMENT. MEAN STORM FLOW AROUND 50KT
SUGGEST ORGANIZED BOW-TYPE STRUCTURES COULD EASILY ACCELERATE BEYOND
THESE SPEEDS PRODUCING POTENTIALLY DESTRUCTIVE DAMAGING WINDS. ANY
HEATING AHEAD OF THIS LINE WILL ONLY SERVE TO AID UPDRAFT POTENTIAL
AS THUNDERSTORMS SPREAD/DEVELOP NEWD TOWARD SRN WI/WRN IND/SWRN
LOWER MI BY NOON. IT/S NOT ENTIRELY CLEAR WHETHER DISCRETE
STRUCTURES THAT EVOLVE LATER IN THE AFTERNOON ALONG ADVANCING WIND
SHIFT WILL REMAIN ISOLATED OR EVOLVE INTO MORE NUMEROUS
CLUSTERS/LINE SEGMENTS. REGARDLESS...EMBEDDED SUPERCELLS MAY
PRODUCE TORNADOES IN ADDITION TO DAMAGING WINDS.

...GULF STATES...

WITH INTENSE LARGE SCALE FORCING EXPECTED TO SHIFT WELL NORTH OF THE
GULF STATES...BROAD BUT POTENTIALLY SIGNIFICANT LOW LEVEL WARM
ADVECTION WILL GRADUALLY INCREASE DURING THE OVERNIGHT HOURS ACROSS
PORTIONS OF AL INTO GA. THIS INCREASE IN WARM ADVECTION WILL BE DUE
MOSTLY TO SWLY LLJ THAT SHOULD EVOLVE WELL AHEAD OF MAIN UPPER
TROUGH AXIS. THERMODYNAMIC PROFILES ACROSS THIS REGION WILL PROVE
QUITE MOIST WITH PRECIPITABLE WATER VALUES LIKELY IN EXCESS OF 2
INCHES. WITH SFC DEW POINTS EXPECTED TO RISE INTO THE LOWER-MID
70S...ENHANCED LOW-MID LEVEL SHEAR WILL CREATE A FAVORABLE
ENVIRONMENT FOR STORM ROTATION. WEAK LAPSE RATES WILL NEGATE
UPDRAFT STRENGTH...BUT ISOLATED SUPERCELLS NONETHELESS MAY
OCCUR...ESPECIALLY DURING THE OVERNIGHT HOURS. ISOLATED TORNADOES
AND DAMAGING WINDS ARE THE PRIMARY SEVERE THREATS.

..DARROW.. 10/17/2007

CLICK TO GET WUUS02 PTSDY2 PRODUCT

NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0800Z
CURRENT UTC TIME: 1717Z (1:17PM), RELOAD THIS PAGE TO UPDATE THE TIME

[6SpeedTA95]

Last 30 mins we've gotten very thick cloud cover here.

[Ed Mahmoud]

Things have calmed down a tad.

Are the storms approaching I-35 the last hurrah for the I-35 corridor in OK and TX, with the big show moving into Eastern OK, extreme NE Texas, Arkansas, Kansas and Missouri, or will one more round go on the dry line before the afternoon is done?

[Ed Mahmoud]

Last 30 mins we've gotten very thick cloud cover here.

t-storm warning for OKC metro.

[CrazyC83]

Current conditions in the threat area:

Arkansas
Batesville - Mostly cloudy, 73 (68)
El Dorado - Mostly cloudy, 75 (72)
Fayetteville - Mostly cloudy, 69 (65)
Fort Smith - Mostly cloudy, 71 (66)
Jonesboro - Mostly cloudy, 73 (68)
Little Rock - Rainshower, 72 (70)
Mena - Mostly cloudy, 77 (72)
Monticello - Mostly cloudy, 77 (70)
Mountain Home - Fog, 67 (65)
Pine Bluff - Light rainshower, 74 (71)
Russellville - Overcast, 71 (67)
Searcy - Light rainshower, 71 (69)
Texarkana - Overcast, 76 (71)

Kansas
Chanute - Overcast, 62 (60)
Coffeyville - Mostly cloudy, 75 (66)
Emporia - Light rain, 62 (59)
Wichita - Light rain, 62 (60)

Louisiana
Alexandria - Mostly cloudy, 82 (73)
Lafayette - Mostly cloudy, 84 (73)
Lake Charles - Mostly cloudy, 82 (73)
Monroe - Mostly cloudy, 79 (72)
Shreveport - Light rainshower, 77 (71)

Mississippi
Greenville - Mostly cloudy, 77 (70)
Natchez - Partly cloudy, 84 (72)

Missouri
Cape Girardeau - Partly cloudy, 75 (68)
Columbia - Overcast, 65 (61)
Joplin - Mostly cloudy, 76 (64)
Kansas City - Light rain, 64 (58)
Poplar Bluff - Mostly cloudy, 74 (67)
Rolla - Mostly cloudy, 70 (64)
St. Louis - Light rainshower, 62 (60)
Springfield - Overcast, 68 (63)
West Plains - Fog, 65 (64)

Oklahoma
Ada - Mostly cloudy, 75 (70)
Altus - Partly cloudy, 77 (67)
Bartlesville - Mostly cloudy, 73 (65)
Enid - Thunderstorm, 61 (59)
Lawton - Partly cloudy, 73 (66)
McAlester - Mostly cloudy, 74 (68)
Muskogee - Partly cloudy, 75 (67)
Norman - Mostly cloudy, 72 (70)
Oklahoma City - Overcast, 71 (65)
Stillwater - Thunderstorm, 63 (59)
Tulsa - Mostly cloudy, 75 (66)
Woodward - Sunny, 72 (63)

Tennessee
Dyersburg - A few clouds, 79 (66)
Jackson - Partly cloudy, 79 (68)
Memphis - Mostly cloudy, 76 (67)

Texas
Abilene - Sunny, 81 (58)
Beaumont - Light rain, 78 (75)
DFW - Light rainshower, 80 (69)
Greenville - Mostly cloudy, 77 (72)
Jasper - Light rain, 78 (75)
Lufkin - Light rainshower, 79 (73)
Mount Pleasant - Overcast, 73 (70)
Paris - Overcast, 73 (72)
Sherman - Overcast, 73 (68)
Tyler - Haze, 76 (71)
Wichita Falls - Mostly cloudy, 78 (64)

[CrazyC83]

For some reason, it seems that fall outbreaks can form easier in cloudy conditions...

[CrazyC83]

Things have calmed down a tad.

Are the storms approaching I-35 the last hurrah for the I-35 corridor in OK and TX, with the big show moving into Eastern OK, extreme NE Texas, Arkansas, Kansas and Missouri, or will one more round go on the dry line before the afternoon is done?

No part of that watch has been dropped, so the potential probably exists for more severe weather along and west of I-35. I think the big stuff is this evening though.

[CrazyC83]

MESOSCALE DISCUSSION 2093
NWS STORM PREDICTION CENTER NORMAN OK
1258 PM CDT WED OCT 17 2007

AREAS AFFECTED...PARTS OF SW NEB...W CNTRL KS

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 171758Z - 171930Z

TRENDS ARE BEING MONITORED FOR AN INCREASING SEVERE THREAT AND THE
POSSIBILITY OF A WW.

LOWER/MID TROPOSPHERIC CIRCULATION MAY BE IN THE PROCESS OF FORMING
TO THE NORTH/NORTHWEST OF HILL CITY KS. ASSOCIATED FORCING FOR
UPWARD VERTICAL MOTION WITH THIS FEATURE MAY AID CONVECTIVE
DEVELOPMENT BY 19-21Z...IN LOW-LEVEL WARM ADVECTION REGIME EAST OF
SURFACE DRY LINE. ADDITIONAL ISOLATED STORM DEVELOPMENT MAY FOLLOW
SUITE THEREAFTER...SOUTHWARD ALONG DRY LINE TOWARD MEDICINE LODGE.

A NARROW CORRIDOR OF MIXED LAYER CAPE UP TO AROUND 1000 J/KG IS
POSSIBLE ACROSS THIS REGION BY PEAK AFTERNOON HEATING. AND...DEEP
LAYER SHEAR BENEATH 30-50 KT SOUTH SOUTHWESTERLY 500 MB FLOW IS
SUFFICIENT FOR SUPERCELLS. LOW-LEVEL HODOGRAPHS MAY NOT BE
PARTICULARLY LARGE...BUT FAVORABLE AMBIENT VERTICAL VORTICITY AND
STEEP LOW-LEVEL LAPSE RATES PROBABLY WILL BE SUPPORTIVE OF AT LEAST
BRIEF TORNADOES...IN ADDITION TO THE RISK FOR LARGE HAIL/DAMAGING
WIND GUSTS.

..KERR.. 10/17/2007


ATTN...WFO...ICT...OUN...GID...DDC...GLD...

40210002 40969988 40759837 39649828 38169861 37619864
37239857 36989983 37700012 38830008 39000031

New activity to the north and west?

[6SpeedTA95]

For some reason, it seems that fall outbreaks can form easier in cloudy conditions...

It's because the thermo is typically weaker during the fall but there's other incredients like sheer and lapse rates that can contribute significantly to severe weather outbreaks that tend to be prevelant in the fall.

[CrazyC83]

000
FXUS64 KTSA 171807
AFDTSA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
107 PM CDT WED OCT 17 2007

.MESOSCALE UPDATE...
THUNDERSTORMS ARE INCREASING IN THE I-35 CORRIDOR FROM
OKLAHOMA CITY SOUTH. THIS ACTIVITY IS AT THE EDGE OF
OUR HIGH-RESOLUTION CONVECTIVE ANALYSIS GRIDS...BUT IT APPEARS
THE CAP INDEX IS STILL RATHER HIGH JUST AHEAD OF THESE CELLS
SO THE STORMS ARE NOT LIKELY ROOTED IN THE BOUNDARY LAYER.
HOWEVER...THE ATMOSPHERE WILL CONTINUE TO DESTABILIZE AHEAD OF
THESE STORMS AND THIS OUTBREAK MAY WELL KICK OFF WITH
THIS ACTIVITY BECOMING SURFACE BASED LATER THIS AFTERNOON.

A THUNDERSTORM BOUNDARY FROM THE EARLIER STORMS IS IN PLACE
FROM NEAR COFFEYVILLE KANSAS TO BARTLESVILLE TO PAWNEE. THIS
BOUNDARY MAY SHIFT A LITTLE MORE TO THE SOUTHEAST...BUT IT
LIKELY WILL NOT MOVE MUCH. A MAXIMIZED TORNADO THREAT IS
EXPECTED NEAR THIS BOUNDARY WHERE STRONG DIFFERENTIAL
HEATING IS OCCURRING. THE BOUNDARY IS LAID OUT ALONG THE
EXPECTED STORM MOTIONS AND THIS WILL INCREASE THE RESIDENCE
TIME OF CELLS IN THIS FAVORABLE ENVIRONMENT AND FURTHER
ENHANCE A STRONG TORNADO POTENTIAL.

AT 17Z CAPE OF 1500 TO 2000 J/KG HAVE DEVELOPED NEAR THE
BOUNDARY WITH CAPE TO 700 MB NEAR 100 J/KG DEVELOPING IN
POCKETS NEAR THE BOUNDARY AS WELL. GIVEN THE INCREASING
SHEAR PROFILE THAT IS EXPECTED TO CONTINUE DEVELOPING
INTO THE EVENING...THE INSTABILITY BEING CALCULATED IS MORE
THAN ENOUGH TO SUPPORT A TORNADO OUTBREAK. THE PEAK
TORNADO THREAT IS EXPECTED THIS EVENING AS THE SURFACE LOW
IN KANSAS DEEPENS AND THE TYPICAL DIURNAL INCREASE
IN THE LOW-LEVEL WINDS TAKES PLACE.

ALL INTERESTS IN EASTERN OKLAHOMA AND NORTHWEST ARKANSAS SHOULD
CLOSELY MONITOR THIS POTENTIALLY DANGEROUS EVENT.


&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&

$$

SHORT TERM...08

[CrazyC83]

MESOSCALE DISCUSSION 2094
NWS STORM PREDICTION CENTER NORMAN OK
0120 PM CDT WED OCT 17 2007

AREAS AFFECTED...ERN OK

CONCERNING...TORNADO WATCH 708...709...

VALID 171820Z - 171945Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 708...709...CONTINUES.

POTENTIAL FOR TORNADOES IS EXPECTED TO INCREASE WITHIN THE NEXT FEW
HOURS ACROSS EASTERN OKLAHOMA/NORTHEAST TEXAS. AN ADDITIONAL WW WILL
BE NEEDED TO INCLUDE PARTS OF NORTHEAST TEXAS/SOUTHEAST OKLAHOMA.
IT IS UNCERTAIN AT THE MOMENT WHETHER THIS WILL INCLUDE REPLACEMENT
OF WW 708/709.

MID-LEVEL TROUGH AXIS IS IN THE PROCESS OF TAKING ON AN INCREASINGLY
NEGATIVE TILT AND PIVOTING NORTHEAST OF THE SOUTHERN HIGH
PLAINS...TOWARD THE OZARK PLATEAU. AS FORCING FOR UPWARD VERTICAL
MOTION ASSOCIATED WITH THIS FEATURE SPREADS EAST OF THE INTERSTATE
35 CORRIDOR OF OKLAHOMA/NORTH CENTRAL TEXAS LATE THIS
AFTERNOON...REMAINING INHIBITION WILL WEAKEN.

SQUALL LINE NOW FORMING ALONG THE INTERSTATE 35 CORRIDOR WILL LIKELY
INTENSIFY NEXT FEW HOURS AS IT SHIFTS EASTWARD IN STRONGLY SHEARED
ENVIRONMENT WITH MIXED LAYER CAPE ON THE ORDER OF 1000 J/KG.
ADDITIONALLY...MORE DISCRETE STORMS MAY BEGIN TO FORM IN ADVANCE OF
THE LINE DURING THE 19-21Z TIME FRAME. LARGE CLOCKWISE CURVED
LOW-LEVEL HODOGRAPHS AND A BUOYANT BOUNDARY LAYER WITH HIGH
RELATIVELY HUMIDITIES ACROSS EASTERN OKLAHOMA/NORTHEAST TEXAS WILL
BE FAVORABLE FOR TORNADIC DEVELOPMENT IN STRONGEST STORMS. ISOLATED
STRONG TORNADOES ARE POSSIBLE.

..KERR.. 10/17/2007


ATTN...WFO...SHV...TSA...FWD...OUN...

35509705 36249677 36909566 36609470 34739463 33839470
33339530 32869692 33389703

[CrazyC83]

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
1121 AM CDT WED OCT 17 2007

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
172100-
WINNEBAGO-BOONE-MCHENRY-LAKE ILLINOIS-OGLE-LEE-DE KALB-KANE-
DUPAGE-COOK-LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-
IROQUOIS-FORD-LAKE INDIANA-PORTER-NEWTON-JASPER-BENTON-
INCLUDING THE CITIES OF...ROCKFORD...WOODSTOCK...WAUKEGAN...
OREGON...DIXON...DEKALB...AURORA...CHICAGO...OTTAWA...OSWEGO...
MORRIS...JOLIET...KANKAKEE...PONTIAC...WATSEKA...PAXTON...GARY...
VALPARAISO...MOROCCO...RENSSELAER...FOWLER
1121 AM CDT WED OCT 17 2007 /1221 PM EDT WED OCT 17 2007/

...SEVERE THUNDERSTORMS LIKELY THURSDAY AFTERNOON...

AN INTENSIFYING STORM SYSTEM CURRENTLY IN THE PLAINS WILL SURGE
NORTHEAST INTO THE MID AND UPPER MISSISSIPPI RIVER VALLEY
THURSDAY. STRENGTHENING WINDS WILL DRAW MOISTURE FROM THE GULF AND
HELP DESTABILIZE THE AREA TONIGHT. SHOWERS AND THUNDERSTORMS
SHOULD START DEVELOPING TONIGHT AS THE FIRST WAVE ROTATES THROUGH
THE AREA AS A WARM FRONT. THESE FIRST STORMS ARE NOT LIKELY TO BE
SEVERE CONSIDERING THE TIME OF DAY AND WEAKER AVAILABLE ENERGY.

BEHIND THIS FIRST WAVE...STORMS SHOULD SUBSIDE TO SHOWERS IN THE
MORNING HOURS TOMORROW. THE SECOND WAVE HOWEVER WILL ARRIVE WITH
THE COLD FRONT DRIVING EAST ACROSS THE MISSISSIPPI RIVER SEVERAL
HOURS AFTER SUNUP. IF SKIES BREAK OPEN IN THE MID TO LATE
MORNING HOURS...SOLAR HEATING WILL ADD ENERGY TO AN ALREADY VIGOROUS
LOOKING SYSTEM. THESE STORMS WILL ARRIVE IN THE EARLY AFTERNOON
INTO NORTH CENTRAL ILLINOIS AND FINALLY CLEAR NORTHEAST ILLINOIS
AND NORTHWEST INDIANA IN THE EARLY TO MID EVENING.

STRONG DOWNBURSTS TO 70 MPH ARE POSSIBLE WITH THESE STORMS THURSDAY
AFTERNOON AND EVENING. LARGE DAMAGING HAIL ARE ALSO PROBABLE. IF
NOT THREATENING ENOUGH...A FEW TORNADOES ARE ALSO POSSIBLE.

RESIDENTS AND BUSINESSES IN NORTHERN ILLINOIS AND NORTHWEST
INDIANA SHOULD BEGIN PREPARING NOW FOR THIS SIGNIFICANT BOUT OF
SEVERE WEATHER. GATHER VALUABLES AND YOUR WEATHER RADIO AND KEEP
TUNED TO TV AND RADIO TO KEEP ABREAST OF THIS DEVELOPING SEVERE
STORM THREAT.

$$

RLB