2012 U.S Severe Weather (Videos-Photos-Stats-Forecasts)

[cycloneye]

Cycloneye,

Can you explain the map you posted a little bit?

I understand "cap" as a layer of warm air aloft that prohibits or minimizes severe thunderstorm development..

What exactly is the map showing? Where on twisterdata do I click to get that map?

Thank you,
Brandon

Out friend brunota2003 said it all right. Really,the dynamics are not there for a big outbreak as there will not be a strong low pressure,nor the jet stream will be in a favorable position.

[brunota2003]

And of course that area is centered right over tornado alley...a good thing, perhaps?

[cycloneye]

Here is the 4-8 day outlook and it looks like April will go without more big outbreaks than what occured earlier this month.

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0354 AM CDT WED APR 25 2012

VALID 281200Z - 031200Z

...DISCUSSION...
SHORT WAVE DEVELOPMENTS THROUGH THE EXTENDED FORECAST PERIOD REMAIN
HIGHLY UNCERTAIN. HOWEVER...MEDIUM RANGE MODELS ARE SUGGESTIVE THAT
THE BLOCKY UPPER FLOW PATTERN MAY TRANSITION TO A MORE PROGRESSIVE
ONE...AT LEAST ACROSS THE NORTHERN TIER STATES... WHERE A MORE
DISTINCT AND STRONGER ZONAL BELT OF WESTERLIES MAY EVOLVE DURING THE
EARLY TO MIDDLE PORTION OF NEXT WEEK. HIGHER MOISTURE CONTENT AIR
ALSO APPEARS LIKELY TO RETURN INLAND OFF A RECOVERING GULF OF MEXICO
BOUNDARY LAYER THROUGH MOST AREAS EAST OF THE ROCKIES...INCLUDING
65-70F SURFACE DEW POINTS AS FAR NORTH AS THE EAST CENTRAL
PLAINS/LOWER MISSOURI VALLEY REGION BY NEXT TUESDAY/WEDNESDAY.
INCREASING INSTABILITY WILL YIELD INCREASING CONVECTIVE
POTENTIAL...PROBABLY INCLUDING DAILY SEVERE WEATHER THREATS.
HOWEVER...ANY SIGNAL FOR A REGIONAL TYPE SEVERE WEATHER EVENT
REMAINS LOW...AND GENERALLY CONFINED TO THE LATTER PORTIONS OF THE
PERIOD...WHEN PATTERN PREDICTABILITY IS AT ITS LOWEST.

..KERR.. 04/25/2012

[CrazyC83]

And certainly not like one year ago, when the atmosphere had already taken off...but it would just be an appetizer for the catastrophe.

[cycloneye]

The long range forecast suggests that next week will have severe weather,but is still too early to pinpoint a definite area. Stay tuned.

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0341 AM CDT THU APR 26 2012

VALID 291200Z - 041200Z

...DISCUSSION...
MEDIUM RANGE MODELS CONTINUE TO INDICATE A TRANSITION TO A MORE
PROGRESSIVE...ZONAL UPPER FLOW REGIME ACROSS THE NORTHERN TIER OF
THE U.S. BY EARLY NEXT WEEK. AND IT STILL APPEARS THAT THIS WILL
COINCIDE WITH SUBSTANTIVE LOW-LEVEL MOISTENING THROUGH A LARGE
PORTION OF THE CENTRAL AND EASTERN U.S...WHICH SHOULD CONTRIBUTE TO
INCREASING POTENTIAL INSTABILITY AND SCATTERED DAILY SEVERE WEATHER
RISKS. GUIDANCE IS SUGGESTIVE THAT A MORE CONCENTRATED...REGIONAL
SEVERE WEATHER THREAT MAY NOT BE COMPLETELY OUT OF THE QUESTION FROM
PARTS OF THE CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY/GREAT
LAKES REGION NEXT TUESDAY INTO WEDNESDAY. HOWEVER...WITH A
CONSISTENT AND CLEAR SIGNAL STILL LACKING...PREDICTABILITY REMAINS
TOO LOW TO ATTEMPT TO DELINEATE A REGIONAL SEVERE AREA.

..KERR.. 04/26/2012

CLICK TO GET WUUS48 PTSD48 PRODUCT

[Cyclenall]

The below 5 reports is for the whole year.

I adjusted it. I didn't need 2010 to make my point anyways.

[Ntxw]

Moderate risk for severe weather and tornadoes in eastern Kansas today. Vigorous shortwave is proving to be enough for lift with an associated warm front. Jet winds are not that impressive but enough low level shear for localized concern with any storms that develop.



DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0710 AM CDT FRI APR 27 2012

VALID 271300Z - 281200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF CENTRAL/EASTERN KS
AND WEST CENTRAL MO...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CENTRAL
PLAINS...

...AN ACTIVE SEVERE WEATHER EVENT IS EXPECTED LATER THIS AFTERNOON
AND EVENING OVER PARTS OF THE CENTRAL PLAINS...

...CENTRAL PLAINS...
MORNING WATER VAPOR LOOPS SHOW A COMPACT UPPER SHORTWAVE TROUGH OVER
THE CENTRAL ROCKIES. THIS FEATURE WILL EJECT EASTWARD INTO THE
PLAINS TODAY. AN ASSOCIATED 70 KNOT MID LEVEL SPEED MAX WILL
OVERSPREAD PARTS OF OK/KS WHILE THE MAIN SURFACE LOW TRACKS ACROSS
KS. STRONG SOUTHERLY LOW LEVEL WINDS AHEAD OF THE LOW WILL HELP A
WARM FRONT LIFT NORTHWARD ACROSS EASTERN KS. THE END RESULT WILL BE
A FOCUSED AREA OF ENHANCED THREAT OF SEVERE THUNDERSTORMS AND
TORNADOES LATER THIS AFTERNOON AND EVENING.

SCATTERED THUNDERSTORMS ARE ONGOING THIS MORNING OVER WESTERN KS
AHEAD OF THE MAIN UPPER SYSTEM. PRESENT INDICATIONS ARE THAT THESE
STORMS MAY CONTINUE THROUGH THE MORNING AND INTENSIFY FURTHER BY
EARLY AFTERNOON OVER CENTRAL KS AS A COMBINATION OF DAYTIME HEATING
AND MOISTURE ADVECTION DESTABILIZE THE REGION. THE CLUSTER OF
STORMS IS EXPECTED TO TRACK EASTWARD ALONG/NORTH OF PRIMARY
INSTABILITY GRADIENT THROUGH THE DAY ACROSS CENTRAL/EASTERN KS AND
EVENTUALLY TOWARD THE KC AREA BY EARLY EVENING. BACKED LOW LEVEL
WINDS AND ENHANCED VERTICAL SHEAR NEAR THE WARM FRONT WILL PROMOTE
SUPERCELL STRUCTURES CAPABLE OF LARGE HAIL. STORMS MAY EVENTUALLY
BECOME SURFACE BASED BY LATE AFTERNOON WITH AN INCREASING RISK OF
TORNADOES /POSSIBLY STRONG/.

FARTHER SOUTH...MODEL SOLUTIONS ARE IN GOOD AGREEMENT THAT DISCRETE
CONVECTION WILL FORM ALONG THE DRYLINE OVER SOUTH CENTRAL KS BY LATE
AFTERNOON. THIS ACTIVITY WILL FORM IN A REGION OF STRONG
INSTABILITY AND FAVORABLE VERTICAL SHEAR FOR DISCRETE SUPERCELLS
CAPABLE OF VERY LARGE HAIL AND TORNADOES. THE WARM SECTOR WILL BE
RATHER NARROW...BUT WILL BE SHIFTING SLOWLY EASTWARD THROUGH THE
EVENING. IT CURRENTLY APPEARS THE MOST INTENSE STORMS WILL TRACK AS
FAR EAST AS WESTERN MO BEFORE A SLOW WEAKENING PROCESS THIS EVENING.

[cycloneye]

Day 4=8 outlook issued on 4/28/12.

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0406 AM CDT SAT APR 28 2012

VALID 011200Z - 061200Z

...DISCUSSION...
MODEL CONSENSUS IS THAT UPPER PATTERN WILL HAVE TRANSITIONED TO A
QUASI-ZONAL PROGRESSIVE BY TUESDAY /DAY 4/. MODIFIED CP AIR WILL
GRADUALLY RETURN NWD THROUGH THE PLAINS...MS AND OH VALLEYS BENEATH
MODERATELY STRONG FLOW ALOFT. POTENTIAL FOR A HIGHER COVERAGE OF
SEVERE STORMS MAY EVOLVE OVER ERN PORTIONS OF THE NRN PLAINS INTO
THE UPPER MS VALLEY DAY 4 DOWNSTREAM FROM AN EJECTING SHORTWAVE
TROUGH. HOWEVER...MODELS DIFFER ON AMPLITUDE AND TIMING OF THIS
FEATURE WITH THE ECMWF BEING SLOWER AND EJECTING THE IMPULSE NORTH
OF THE MORE UNSTABLE WARM SECTOR. THERE IS ALSO UNCERTAINTY
REGARDING HOW EARLY WARM ADVECTION STORMS WILL AFFECT NWD BOUNDARY
LAYER RECOVERY.

SEVERE THREAT WILL LIKELY SHIFT A LITTLE FARTHER EAST TOWARD THE
GREAT LAKES AND OH VALLEY WEDNESDAY /DAY 5/ AS ANOTHER IMPULSE MOVES
THROUGH THE TROUGH AND STORMS DEVELOP ALONG AND JUST AHEAD OF A COLD
FRONT SUPPORTED BY A MOISTENING WARM SECTOR.

..DIAL.. 04/28/2012

[Dave]

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 198
NWS STORM PREDICTION CENTER NORMAN OK
435 PM EDT SAT APR 28 2012

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

SOUTHERN INDIANA
NORTHERN KENTUCKY

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 435 PM UNTIL
1100 PM EDT.

SCATTERED DAMAGING WINDS
ISOLATED WIND GUSTS TO 70 MPH POSSIBLE
SCATTERED LARGE HAIL
ISOLATED HAIL TO 2.5 INCHES IN DIAMETER POSSIBLE
ISOLATED TORNADOES

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 40
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 35 MILES SOUTH
SOUTHWEST OF TERRE HAUTE INDIANA TO 25 MILES NORTH NORTHEAST OF
LEXINGTON KENTUCKY. FOR A COMPLETE DEPICTION OF THE WATCH SEE
THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 197...

DISCUSSION...TSTMS CURRENTLY ACROSS SRN IL ARE EXPECTED TO EXPAND
AND SPREAD EAST ACROSS PORTIONS OF SRN IND AND THEN ACROSS THE OH
RIVER INTO NRN KY THROUGH THIS EVENING. THIS ACTIVITY IS OCCURRING
NEAR A WEAK SURFACE LOW AND ALONG A WARM/QUASI-STATIONARY FRONT FROM
NEAR STL ESEWD TO NEAR LMK. AIR MASS FUELING ONGOING AND ANTICIPATED
DEVELOPMENT IS MODERATELY TO STRONGLY UNSTABLE AND WILL CONTINUE TO
SUPPORT STOUT STORM UPDRAFTS AMIDST MORE THAN SUFFICIENT VERTICAL
SPEED SHEAR FOR STORM ORGANIZATION AND SUPERCELL STRUCTURES.
GREATEST THREAT IN THE SHORT TERM WILL BE THE PROSPECT FOR LARGE
HAIL. DAMAGING WIND POTENTIAL MAY INCREASE AS CLUSTERS MERGE...GROW
UPSCALE...AND THEN RESULT IN A DEEPENING COLD POOL AND MCS
ACCELERATING ESEWD ACROSS THE OH RIVER. A NARROW CORRIDOR OF TORNADO
POTENTIAL ALSO EXISTS INVOF SHARP FRONTAL ZONE BUT THIS POTENTIAL
APPEARS TOO LOCALIZED ATTM TO SUPPORT A TORNADO WATCH FOR THE LARGER
AREA AT RISK FROM HAIL AND HIGH WINDS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 28030.


...CARBIN

[Dave]

DAVIESS-KNOX-MARTIN-
614 PM EDT SAT APR 28 2012

...A TORNADO WARNING REMAINS IN EFFECT FOR CENTRAL DAVIESS...EAST
CENTRAL KNOX AND CENTRAL MARTIN COUNTIES UNTIL 630 PM EDT...

AT 609 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED NEAR WASHINGTON...OR 15 MILES NORTHEAST OF
PETERSBURG...MOVING EAST AT 40 MPH.

IN ADDITION...80 TO 90 MPH WINDS WERE REPORTED IN WASHINGTON WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
SHOALS...CANNELBURG...WEST BOGGS LAKE...BURNS CITY...LOOGOOTEE...
INDIAN SPRINGS AND LACY.

[Dave]

BULLETIN - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH OUTLINE UPDATE FOR WT 199
NWS STORM PREDICTION CENTER NORMAN OK
515 PM CDT SAT APR 28 2012

TORNADO WATCH 199 IS IN EFFECT UNTIL 1000 PM CDT FOR THE
FOLLOWING LOCATIONS

ILC027-047-055-059-065-077-081-121-133-145-157-163-165-185-189-
191-193-199-290300-
/O.NEW.KWNS.TO.A.0199.120428T2215Z-120429T0300Z/

IL
. ILLINOIS COUNTIES INCLUDED ARE

CLINTON EDWARDS FRANKLIN
GALLATIN HAMILTON JACKSON
JEFFERSON MARION MONROE
PERRY RANDOLPH SALINE
ST. CLAIR WABASH WASHINGTON
WAYNE WHITE WILLIAMSON


INC025-037-051-061-117-123-125-129-147-163-173-290300-
/O.NEW.KWNS.TO.A.0199.120428T2215Z-120429T0300Z/

IN
. INDIANA COUNTIES INCLUDED ARE

CRAWFORD DUBOIS GIBSON
HARRISON ORANGE PERRY
PIKE POSEY SPENCER
VANDERBURGH WARRICK


KYC027-059-091-101-163-225-290300-
/O.NEW.KWNS.TO.A.0199.120428T2215Z-120429T0300Z/

KY
. KENTUCKY COUNTIES INCLUDED ARE

BRECKINRIDGE DAVIESS HANCOCK
HENDERSON MEADE UNION


MOC099-157-186-187-221-290300-
/O.NEW.KWNS.TO.A.0199.120428T2215Z-120429T0300Z/

MO
. MISSOURI COUNTIES INCLUDED ARE

JEFFERSON PERRY ST. FRANCOIS
STE. GENEVIEVE WASHINGTON


ATTN...WFO...LSX...PAH...LMK...

[brunota2003]

Storm that has produced winds up to 80 or 90 mph (estimated) and baseball sized hail is heading toward Louisville, KY

Radar is estimating hail up to 5.00 inches with this cell!

[brunota2003]

Here are a couple images showing (left) radar estimated hail size and (right) Storm Relative Velocity. The first image is zoomed out showing where Louisville, KY is...the second zoomed in. You can see my scale only goes to 5 inches!





Thankfully, ground reports currently coming in are only going up to about golf ball sized (1.75 inches).

[brunota2003]

There was a big event going on today in Louisville, and the NWS just received a report of golf ball sized hail (from NWS employee) near where the event was taking place. I hope everyone sought shelter!


This was the plea put out by the Weather Office over an hour ago:

SevereThunderstorms headed for Louisville metro!

A large, severe thunderstorm over southern Indiana is headed directly for the Louisville metro area. With all of the Derby Festival acitivities going on this evening, this storm will post a dangerous threat and shelter should be sought out before 8pm! This severe storm will not only produce ample, deadly lightning, but large hail up to the size of golfballs, as well as straight line winds of up to 60mph or more. Prepare to take shelter now!


AT 643 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
SEVERE THUNDERSTORM IN ORANGE COUNTY...TO THE NORTHWEST OF
LOUISVILLE. THIS STORM WAS MOVING SOUTHEAST AT 35 MPH. THIS STORM
PRODUCED BASEBALL SIZED HAIL AT THE FRENCH LICK AIRPORT AT 645 PM EDT

THIS IS A VERY DANGEROUS STORM. IF IT STAYS SEVERE...IT WILL IMPACT
THE LOUISVILLE WATERFRONT AND DOWNTOWN AREAS AROUND 8 PM. AT LEAST
QUARTER SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 70 MPH...ARE
EXPECTED WITH THIS STORM. PERSONS OUTDOORS SHOULD TAKE SHELTER.

* THIS STORM WILL ALSO IMPACT...
DOWNTOWN LOUISVILLE

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE AWARE THAT A GUST FRONT PRECEDING THIS STORM WILL GENERATE STRONG
AND GUSTY WINDS WELL BEFORE THE ARRIVAL OF ANY RAIN.

STRONG WINDS WITH THIS STORM CAN TOPPLE WEAKLY ROOTED TREES...AND
DOWN POWER LINES. TAKE PRECAUTIONS NOW TO SECURE TRASH CANS...LAWN
FURNITURE AND OTHER LOOSE OUTDOOR OBJECTS. MOTORISTS IN HIGH PROFILE
VEHICLES SHOULD USE CAUTION.

IF YOU ARE IN THE PATH OF THIS STORM...SEEK SHELTER INDOORS AND STAY
AWAY FROM WINDOWS.

[brunota2003]

Got a couple images from the traffic cameras in and around Louisville, KY of the hail falling:

[cycloneye]

No big outbreak is expected for this week,according to the SPC long range forecast.

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0400 AM CDT SUN APR 29 2012

VALID 021200Z - 071200Z

...DISCUSSION...
MODEL CONSENSUS IS THAT A QUASI-ZONAL PATTERN WILL PERSIST THROUGH
AT LEAST DAY 5 WITH PRIMARY BELT OF WLYS OVER THE NRN THIRD OF THE
COUNTRY. THREAT OF SEVERE STORMS MAY PERSIST FROM PORTIONS OF THE
CNTRL PLAINS INTO MID-UPPER MS VALLEY...GREAT LAKES AND OH VALLEY
DAY 4-5 IN VICINITY OF NE-SW ORIENTED STALLED FRONT AND WHERE A
MOIST WARM SECTOR WILL HAVE ADVECTED NWD BENEATH THE STRONGER WLYS.
HOWEVER...CONSIDERABLE MODEL VARIABILITY EXISTS REGARDING TIMING AND
AMPLITUDE OF INDIVIDUAL WAVES MOVING THROUGH THIS FLOW REGIME. THIS
IN CONJUNCTION WITH AREAS OF ONGOING CONVECTION LOWER CONFIDENCE IN
WHERE A HIGHER COVERAGE OF SEVERE STORMS MAY DEVELOP.

..DIAL.. 04/29/2012

[wx247]

A few severe thunderstorm watches ongoing across the plains tonight, including here in SW MO until 3 a.m.

[wx247]

Tornadic cell with monster hail is heading into the south side of Lubbock soon.

[Brandon8181]

Storm that has produced winds up to 80 or 90 mph (estimated) and baseball sized hail is heading toward Louisville, KY

Radar is estimating hail up to 5.00 inches with this cell!

What is that software you are using??

I like it!

[brunota2003]

Storm that has produced winds up to 80 or 90 mph (estimated) and baseball sized hail is heading toward Louisville, KY

Radar is estimating hail up to 5.00 inches with this cell!

What is that software you are using??

I like it!

http://grlevelx.com/

I use Grlevel2 Analyst...it is a bit pricey though. Most people here use GRLevel3.