Severe Weather - Week of May 22 Sunday thru Thursday

[Dave]

Day 1 - May 22 (Sunday)



DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0755 AM CDT SUN MAY 22 2011

VALID 221300Z - 231200Z

...THERE IS A MDT RISK OF SVR TSTMS FROM PARTS OF SRN PLNS NORTH AND
EAST INTO THE MID AND UPR MS VLYS...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK
AREA...FROM S TX NORTHEAST TO THE UPR GRT LKS...

...SYNOPSIS...
SD CLOSED LOW EXPECTED TO TRACK ENE TO SRN MN THIS EVE AND EVOLVE
INTO AN OPEN WAVE OVER WI EARLY MON AS BROAD...NEGATIVE TILT
UPSTREAM TROUGH AMPLIFIES SE ACROSS THE WRN U.S. BETWEEN THESE TWO
FEATURES...A WEAK SHORTWAVE RIDGE WILL SHIFT E FROM THE CNTRL/SRN
RCKYS TO THE CNTRL/SRN PLNS. AT THE SFC...A COLD/OCCLUDED FRONT
WILL MOVE E ACROSS THE MID/UPR MS VLY AND ACROSS ERN KS/MO LATER
TODAY/TONIGHT...WHILE FARTHER S...DRYLINE WILL PERSIST FROM SE KS TO
THE TX BIG BEND. THE DRYLINE WILL INTERSECT THE COLD FRONT IN KS
AND WILL RETREAT NW ACROSS THE SRN PLNS LATER IN THE PERIOD.

BOTH THE COLD FRONT AND THE DRYLINE WILL SERVE TO FOCUS INTENSE TSTM
DEVELOPMENT LATER TODAY INTO TONIGHT. GIVEN THE DEGREE OF BOTH
INSTABILITY AND SHEAR PRESENT NEAR THE BOUNDARIES...SOME OF THE
STORMS LIKELY WILL YIELD VERY LARGE HAIL...TORNADOES...AND DMGG
WIND.

...MID/UPR MS VLY TO GRT LKS/OH VLY...
STRENGTHENING SSWLY LLJ AHEAD OF UPR VORT MAX IN BASE OF SD UPR LOW
SHOULD ALLOW FOR SUBSTANTIAL AIR MAS RECOVERY NWD ACROSS MUCH OF
IA...SE MN...NRN MO...IL...AND WI THIS MORNING...IN WAKE OF
OVERNIGHT SQLN. WITH TIME...LOW LVL MOISTURE SHOULD ALSO SPREAD
NEWD FROM THE MID MS VLY INTO THE GRT LKS/OH VLY. COUPLED WITH
MODERATE SFC HEATING AND RELATIVELY COOL MID LVL TEMPS...EXPECT
2000-3000 J/KG SBCAPE BY AFTN WHERE STRONGEST HEATING OCCURS.

COMBINATION OF STRONG DESTABILIZATION WITH CONVERGENCE ALONG/AHEAD
OF AFOREMENTIONED COLD/OCCLUDED FRONT...AND INCREASING UVV SHOULD
SUPPORT SEVERAL BROKEN BANDS OF STORMS OVER PARTS OF IA...SE
MN...AND WRN WI BY MIDDAY. ADDITIONAL STORMS SHOULD DEVELOP SWD AND
EWD INTO PARTS OF MO AND WRN/NRN IL BY MID TO LATE AFTN AS BAND OF
50 KT 700 MB FLOW OVERSPREADS REGION ON S SIDE OF UPR VORT.

GIVEN STRENGTH OF WIND FIELD AND DEGREE OF INSTABILITY...POTENTIAL
WILL EXIST FOR NUMEROUS SUPERCELL STORMS. WHILE DESTRUCTIVE
INTERFERENCE ULTIMATELY MAY LIMIT STORM LONGEVITY...A WINDOW OF
OPPORTUNITY WILL EXIST FOR A FEW SUSTAINED SUPERCELLS POSING A
THREAT FOR STRONG TORNADOES IN ADDITION TO LARGE HAIL/LOCALLY DMGG
WIND....ESPECIALLY FROM WRN WI SWD THROUGH SE MN INTO ERN IA...WRN
IL...AND POSSIBLY NE MO. WITH TIME...STRENGTH OF FORCING AND
CONTINUED ENE MOTION OF UPR VORT SUGGEST THAT THE ACTIVITY WILL
EVOLVE INTO A BROKEN QLCS...WITH A THREAT FOR DMGG WIND...SVR HAIL
AND ISOLD TORNADOES CONTINUING EWD TO THE CHICAGO AREA AND POSSIBLY
INTO PARTS OF LWR MI/IND TONIGHT.

...SRN PLNS...
VERY RICH GULF MOISTURE...WITH LOW 70S F SFC DEWPOINTS AND PW AROUND
1.75 INCHES...WILL PERSIST/SPREAD NWD ACROSS THE SRN HALF OF THE
PLNS TODAY BENEATH BROAD STEEP MID LVL LAPSE RATE PLUME ASSOCIATED
WITH SRN STREAM WSWLY FLOW/EML. COUPLED WITH STRONG SFC
HEATING...SETUP LIKELY WILL YIELD A CORRIDOR OF VERY STRONG
INSTABILITY /SBCAPE UP TO 6000 J PER KG/ ALONG AND AHEAD OF DRY
LINE/COLD FRONT FROM S CNTRL TX NEWD INTO SE KS...SW MO...AND NW AR
BY LATE TODAY.

LARGE SCALE FORCING FOR ASCENT WILL BE WEAK THROUGH THE
PERIOD...WITH SLIGHT HEIGHT RISES POSSIBLE AS LOW AMPLITUDE RIDGE
APPROACHES REGION. IN ADDITION...APPRECIABLE CINH WILL BE PRESENT
DUE TO EML. BUT COMBINATION OF STRONG INSTABILITY WITH SLIGHTLY
CONFLUENT LOW LVL SSWLY FLOW SHOULD SUPPORT AT LEAST WDLY SCTD
INTENSE STORMS FROM ERN OK INTO SW MO/NW AR BY LATE IN THE DAY.
MORE ISOLD INTENSE ACTIVITY ALSO MAY OCCUR FROM CNTRL OK SWD INTO S
CNTRL TX.

GIVEN DEGREE OF INSTABILITY AND AMPLE DEEP SHEAR FOR
SUPERCELLS...POTENTIAL WILL BE VERY HIGH FOR AT LEAST A FEW
INSTANCES OF EXTREMELY LARGE HAIL...IN ADDITION TO TORNADOES/LOCALLY
DMGG WIND. STRENGTHENING LLJ AFTER NIGHTFALL AND CONTINUING
PRESENCE OF VERY RICH MOISTURE SUGGEST THAT THE TORNADO THREAT COULD
CONTINUE WELL INTO THE EVENING.

ADDITIONAL STORMS MAY FORM OVER PARTS OF CNTRL AND NW TX AND
CNTRL/WRN OK LATE TONIGHT AND EARLY MONDAY AS LLJ CONTINUES TO
STRENGTHEN AND SLIGHTLY BACKS AHEAD OF AMPLIFYING SRN STREAM
TROUGH...ENHANCING WAA/MOISTURE FLUX INVOF RETREATING DRY LINE.

...LWR TN/LWR OH VLYS...
TSTM COMPLEX NOW OVER AR MAY PERSIST THROUGH MIDDAY AND BE
ACCOMPANIED BY ADDITIONAL DEVELOPMENT NEWD INTO THE TN/LWR OH VLYS
AS AREA OF LOW LVL MOISTURE RETURN DESTABILIZES BENEATH SRN FRINGE
OF CYCLONIC MID/UPR LVL FLOW. SUFFICIENT INSTABILITY AND SHEAR WILL
BE PRESENT TO SUPPORT SOME SUSTAINED ACTIVITY AND POSSIBLY
ORGANIZATION INTO ONE OR TWO NEW CLUSTERS POSING A THREAT FOR DMGG
WIND/HAIL AND...ASSUMING FAVORABLE STORM MODE... POSSIBLY A COUPLE
TORNADOES THROUGH AT LEAST EARLY TONIGHT.

..CORFIDI/SMITH.. 05/22/2011

[Dave]

http://www.spc.noaa.gov/products/outlook/day1otlk.html

ZCZC SPCPWOSPC ALL
WOUS40 KWNS 220950
IAZ000-ILZ000-MNZ000-MOZ000-WIZ000-221800-

PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0450 AM CDT SUN MAY 22 2011

...SEVERE THUNDERSTORMS EXPECTED OVER PARTS OF THE MID AND UPPER
MISSISSIPPI VALLEY THIS AFTERNOON AND EVENING...

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
DEVELOPMENT OF TORNADOES...LARGE HAIL AND DAMAGING WINDS OVER PARTS
OF THE MID AND UPPER MISSISSIPPI VALLEY THIS AFTERNOON AND EVENING.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE

EASTERN AND SOUTHERN IOWA
WESTERN AND NORTHERN ILLINOIS
SOUTHEAST MINNESOTA
NORTHEAST MISSOURI
WESTERN AND SOUTHERN WISCONSIN

ELSEWHERE...SEVERE STORMS ARE ALSO POSSIBLE FROM THE SOUTHERN PLAINS
THROUGH THE OZARKS INTO THE UPPER GREAT LAKES.

A POTENT UPPER LEVEL STORM CONTAINING STRONG JET STREAM WINDS NOW
OVER NEBRASKA WILL TRACK NORTHEAST INTO SOUTHERN MINNESOTA LATER
TODAY...AND INTO WISCONSIN TONIGHT.

AHEAD OF THIS FEATURE...INCREASINGLY WARM AND HUMID AIR WILL SPREAD
NORTHEAST ACROSS MISSOURI INTO MUCH OF IOWA...ILLINOIS...WISCONSIN
AND SOUTHEAST MINNESOTA.

A COLD FRONT ASSOCIATED WITH THE UPPER LEVEL DISTURBANCE WILL SWEEP
EAST ACROSS THOSE STATES LATER TODAY AND TONIGHT...AND WILL SERVE AS
A FOCUS FOR INTENSE THUNDERSTORMS AS DAYTIME HEATING FURTHER
DESTABILIZES THE REGION.

THE COMBINATION OF STRONG THUNDERSTORMS WITH WIND PROFILES THAT WILL
BE FAVORABLE FOR STORM ROTATION MAY YIELD A FEW TORNADOES...ONE OR
TWO OF WHICH COULD BE STRONG...IN ADDITION TO VERY LARGE HAIL AND
DAMAGING WIND.

WHILE THE GREATEST SEVERE THREAT SHOULD EXIST DURING THE MID TO LATE
AFTERNOON OVER PARTS OF THE MID AND UPPER MISSISSIPPI VALLEYS...A
MORE LIMITED SEVERE RISK MAY CONTINUE THROUGH THE EVENING AS THE
STORMS MERGE INTO A LINE AND CONTINUE EAST TOWARD INDIANA AND LOWER
MICHIGAN.

STATE AND LOCAL EMERGENCY MANAGERS ARE MONITORING THIS DEVELOPING
SITUATION. THOSE IN THE THREATENED AREA ARE URGED TO REVIEW SEVERE
WEATHER SAFETY RULES AND TO LISTEN TO RADIO...TELEVISION...AND NOAA
WEATHER RADIO FOR POSSIBLE WATCHES...WARNINGS...AND STATEMENTS LATER
TODAY.

[Dave]

[Dave]

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 321
NWS STORM PREDICTION CENTER NORMAN OK
705 AM CDT SUN MAY 22 2011

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

SOUTH-CENTRAL AND EASTERN ARKANSAS
FAR NORTHERN MISSISSIPPI
WESTERN TENNESSEE

EFFECTIVE THIS SUNDAY MORNING AND AFTERNOON FROM 705 AM UNTIL 200
PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 70
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 45 MILES WEST
SOUTHWEST OF HOT SPRINGS ARKANSAS TO 45 MILES NORTHEAST OF TUPELO
MISSISSIPPI. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).

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.

DISCUSSION...ON THE NOSE OF A MODERATELY STRONG LOW LEVEL
JET...ELEVATED TSTMS ARE EXPECTED TO CONTINUE TO EXPAND
EAST-NORTHEASTWARD ACROSS AR INTO NORTHERN MS/WESTERN TN THROUGH THE
MORNING. THE 12Z OBSERVED RAOB FROM LITTLE ROCK WAS INDICATIVE OF
STEEP LAPSE RATES ALOFT/AMPLE ELEVATED INSTABILITY...WHICH WILL BE
SUPPORTIVE OF SEVERE HAIL THIS MORNING. IT IS POSSIBLE THAT SOME OF
THESE STORMS MAY REMAIN SUSTAINED AND BECOME SURFACE BASED BY LATE
THIS MORNING/MIDDAY...WITH INCREASING POTENTIAL FOR DAMAGING WIND
GUSTS IN ADDITION TO SEVERE HAIL.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 24030.

[CrazyC83]

One person died last night in Kansas, tragically. The strong tornadic activity came out of nowhere since there was only a Severe Thunderstorm Watch.

[CrazyC83]

New watch coming, quite possibly a PDS:

MESOSCALE DISCUSSION 0849
NWS STORM PREDICTION CENTER NORMAN OK
1053 AM CDT SUN MAY 22 2011

AREAS AFFECTED...MUCH OF ERN IA...NRN MO...NWRN IL...SWRN WI

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

VALID 221553Z - 221800Z

CONDITIONS WILL BECOME QUITE FAVORABLE FOR SUPERCELLS AND TORNADOES
LATER THIS AFTERNOON...AND ONE OR MORE TORNADO WATCHES ARE LIKELY BY
MIDDAY.

VISIBLE SATELLITE IMAGERY SHOWS A WELL DEFINED DRYLINE ACROSS ERN
KS...NWRN MO AND INTO IA WHERE MORE EXTENSIVE CLOUD COVER EXISTED AS
A RESULT OF THE UPPER VORT. MEANWHILE...A PSEUDO-WARM FRONT
EXTENDING FROM CNTRL IA SEWD INTO CNTRL IL...WITH MID TO UPPER 60S F
DEWPOINTS S OF THIS BOUNDARY.

MORNINGS SOUNDINGS SHOWED CLASSIC LOADED GUN WITH SUBSTANTIAL
BOUNDARY LAYER MOISTURE IN PLACE BENEATH A BREAKABLE CAPPING
INVERSION. THE STRONGEST FORCING FOR ASCENT WILL DEVELOP FIRST
ACROSS MN/IA/WI AS THE UPPER LOW CONTINUES EWD. NRN EXTENT OF THREAT
AREA WILL COINCIDE WITH WARM FRONT. OTHER DEVELOPMENT WILL OCCUR SWD
ALONG THE DRYLINE INTO MO AND FAR ERN KS WHERE A SUBSTANTIAL CU
FIELD WAS ALREADY DEVELOPING AND WITH 3000-4000 J/KG MUCAPE. SHEAR
PROFILES ARE FAVORABLE FOR SUPERCELLULAR STORM MODE CAPABLE OF A FEW
STRONG TORNADOES AND VERY LARGE HAIL.

..JEWELL.. 05/22/2011


ATTN...WFO...LOT...ILX...MKX...LSX...DVN...ARX...SGF...DMX...
EAX...TOP...ICT...

LAT...LON 42938956 42448947 41758955 40959003 40179073 38999185
37979346 37929501 38019553 38329550 39859423 41649341
42949303 43529242 43819145 43789045 43328958 42938956

[CrazyC83]

SPC AC 221617

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1117 AM CDT SUN MAY 22 2011

VALID 221630Z - 231200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER SERN MN...ERN IA...PARTS OF
WI/IL/MO...NERN OK AND NWRN AR...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE GREAT LAKES INTO THE
SRN PLAINS...

...UPPER GREAT LAKES INTO THE MID MS AND OH VALLEYS...

DEEP-LAYER CYCLONE OVER ERN SD WILL TRANSLATE EWD INTO THE UPPER MS
VALLEY BY THIS EVENING WITH AN ASSOCIATED 50-60 KT MIDLEVEL JET
STREAK OVERSPREADING THE UPPER MIDWEST THROUGH THE PEAK OF THE
DIURNAL HEATING CYCLE. SURFACE CYCLONE WILL ACCORDINGLY DEVELOP EWD
TO CNTRL MN BY 23/00Z WITH ASSOCIATED WARM FRONT RAPIDLY LIFTING NWD
THROUGH ERN IA/IL INTO WI AND LOWER MI TODAY. HEIGHT FALLS/DYNAMIC
FORCING FOR ASCENT ATTENDANT TO MIDLEVEL SYSTEM COUPLED WITH FRONTAL
UPLIFT WILL FOSTER SCATTERED SVR TSTMS BY EARLY AFTERNOON INITIALLY
FROM PORTIONS OF E-CNTRL/SERN MN AND ERN IA/NERN MO INTO WI/IL.

THE COMBINATION OF A MOIST...MODERATELY TO STRONGLY UNSTABLE AIR
MASS --I.E. MLCAPE RANGING FROM 1000-1500 J/KG OVER MN/WI TO
2000-3000 J/KG ACROSS MO/IL-- COUPLED WITH 40-50 KT DEEP-LAYER SHEAR
ORIENTED ORTHOGONAL TO SURFACE FRONT WILL YIELD A BAND OF SUPERCELLS
CAPABLE OF TORNADOES...LARGE HAIL AND DAMAGING WINDS. THE GREATEST
TORNADO POTENTIAL --SOME POTENTIALLY SIGNIFICANT-- APPEARS TO BE
ACROSS CNTRL/SRN WI INTO IL THIS AFTERNOON AND EVENING WHERE
LOW-LEVEL SHEAR WILL BE ENHANCED BY A GRADUALLY STRENGTHENING LLJ.

STORMS MAY GROW UPSCALE INTO A QLCS TONIGHT WITH A CONTINUED THREAT
FOR MAINLY HAIL AND DAMAGING WIND GUSTS SPREADING EWD THROUGH LOWER
MI AND THE OH VALLEY.

FOR ADDITIONAL NEAR TERM GUIDANCE...SEE MCD 849.

...SRN PLAINS...

12Z REGIONAL SOUNDINGS SHOWED THE POTENTIAL FOR EXPLOSIVE TSTM
DEVELOPMENT LATER TODAY WITH A VERY MOIST BOUNDARY LAYER BENEATH
STEEP MIDLEVEL LAPSE RATES...RESULTING IN MLCAPE OF 3000-4000 J/KG.
GIVEN THAT LARGE-SCALE FORCING FOR ASCENT WILL REMAIN NEGLIGIBLE
THROUGH THE DIURNAL HEATING CYCLE...THE PRIMARY UNCERTAINTIES ARE
LOCATION AND EVENTUAL COVERAGE OF SEVERE STORMS.

DRYLINE LOCATED FROM WRN OK INTO W-CNTRL AND SWRN TX AS OF MID
MORNING WILL MIX MOST RAPIDLY EWD TODAY ACROSS NRN HALF OF OK WITH
THE BOUNDARY EXTENDING FROM E OF THE I-44 CORRIDOR INTO W-CNTRL TX
BY MID/LATE AFTERNOON. CURRENTLY THE HIGHEST PROBABILITY FOR
DIURNAL TSTM DEVELOPMENT APPEARS TO BE FROM NERN OK NEWD INTO MO
WHERE AREA WILL BE INFLUENCED BY LEFT EXIT REGION OF UPPER JET
STREAK STRETCHING FROM THE SRN ROCKIES INTO SRN PLAINS.
HOWEVER...GIVEN THE POTENTIAL FOR STRONG HEATING W OF DRYLINE AND A
BREAKABLE CAP /SEE 12Z FWD SOUNDING/...ISOLATED SEVERE STORMS WILL
BE POSSIBLE ALONG THE LENGTH OF THE DRYLINE.

LATEST MODEL GUIDANCE SUGGESTS DEEPER PBL MIXING MAY LEAD TO
DECREASING LOW-LEVEL MOISTURE CONTENT THIS AFTERNOON...LARGELY
ACROSS PORTIONS OF CNTRL/ERN TX. WHILE THIS MAY TEMPER THE DEGREE
OF INSTABILITY...EXPECT AFTERNOON MLCAPE VALUES OF 3000-4000+ J/KG.
WHEN COUPLED WITH 35-40 KT OF DEEP WLY SHEAR...SETUP WILL FAVOR THE
DEVELOPMENT OF SUPERCELLS WITH VERY LARGE HAIL BEING THE PRIMARY
HAZARD. THE TORNADO THREAT WILL INCREASE IN THE 23/00-03Z TIME
PERIOD AS A STRENGTHENING SLY LLJ ENHANCES LOW-LEVEL SHEAR.

...LOWER MS/TN VALLEYS INTO SRN APPALACHIANS...

REGENERATIVE TSTM DEVELOPMENT IS OCCURRING THIS MORNING ACROSS AR
WITHIN A ZONE OF LOW-LEVEL WAA ASSOCIATED WITH A SWLY LLJ
ORIGINATING OVER SRN TX. CONTINUED HEATING/DESTABILIZATION ALONG
THE SRN/ERN PERIPHERY OF ONGOING STORMS IN CONCERT WITH A
GROWING/DEEPENING COLD POOL MAY ALLOW FOR THE DEVELOPMENT OF A
FORWARD-PROPAGATING MCS WITH EMBEDDED SUPERCELLS WHICH WOULD TRACK
ACROSS THE TN VALLEY AND NRN GULF COAST STATES WITH ATTENDANT
THREATS OF DAMAGING WINDS AND HAIL AND PERHAPS A COUPLE TORNADOES.

FOR ADDITIONAL NEAR-TERM GUIDANCE...SEE MCD 850.

...LOWER GREAT LAKES INTO NC...

THE EWD PROGRESSION OF A COUPLE OF WEAK MIDLEVEL IMPULSES WILL
PROVIDE SUFFICIENT BACKGROUND FORCING TO SUPPORT DIURNAL TSTM
DEVELOPMENT WITHIN A WARMING/DESTABILIZING AIR MASS WHERE AFTERNOON
MLCAPE WILL RANGE FROM 1000-2000 J/KG OVER NC TO AROUND 500 J/KG
ACROSS PORTIONS OF NY/PA. THE STRONGEST VERTICAL SHEAR WILL RESIDE
ACROSS THE LOWER GREAT LAKES...DIMINISHING WITH SWD EXTENT. AS
SUCH...THE POTENTIAL WILL EXIST FOR A FEW STRONG-MARGINALLY SEVERE
STORMS THIS AFTERNOON INTO EVENING WITH THE PRIMARY THREATS BEING
HAIL AND LOCALLY STRONG WIND GUSTS.

..MEAD/GRAMS.. 05/22/2011

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
CURRENT UTC TIME: 1629Z (12:29PM), RELOAD THIS PAGE TO UPDATE THE TIME

[Dave]

MESOSCALE DISCUSSION 0850
NWS STORM PREDICTION CENTER NORMAN OK
1115 AM CDT SUN MAY 22 2011

AREAS AFFECTED...CNTRL AR INTO NRN MS/SWRN TN

CONCERNING...SEVERE THUNDERSTORM WATCH 321...

VALID 221615Z - 221745Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 321
CONTINUES.

A FEW STRONGER CORES CONTINUE TO REGENERATE UPSHEAR ATOP OUTFLOW
FROM PREVIOUS CONVECTION OVER CNTRL AR. WITH STRONG INSTABILITY IN
PLACE AND A PERSISTENT FEED OF MOISTURE NEWD...THIS TREND MAY
PERSIST INTO THE AFTERNOON. HOWEVER...OVERALL ORGANIZATION OF THIS
ACTIVITY APPEARS MINIMAL...WITH SPORADIC HAIL CORES LIKELY AND HEAVY
RAIN.

SHEAR PROFILES IN THIS AREA ARE FAVORABLE FOR SUPERCELLS
THOUGH...AND EVEN A BRIEF TORNADO. THUS...WILL CONTINUE TO MONITOR
THIS AREA FOR ANY UPSCALE GROWTH.

..JEWELL.. 05/22/2011


ATTN...WFO...MEG...JAN...LZK...SHV...

[CrazyC83]

New Tornado Watch coming out for MN/IA/WI. Could be PDS.

[CrazyC83]

Tornado probs are 70/40.

SEL2

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 322
NWS STORM PREDICTION CENTER NORMAN OK
1210 PM CDT SUN MAY 22 2011

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

NORTHEAST IOWA
SOUTHEAST MINNESOTA
WESTERN WISCONSIN

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 1210 PM UNTIL
800 PM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 55 MILES NORTHWEST OF
MANKATO MINNESOTA TO 45 MILES EAST OF LA CROSSE WISCONSIN. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU2).

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 321...

DISCUSSION...SRN FRINGE OF ELEVATED TSTMS ONGOING ACROSS SERN MN/WRN
WI MAY BECOME PROGRESSIVELY SURFACE BASED THIS AFTERNOON OWING TO
THE RAPID NWD FLUX OF 60+ F DEWPOINTS ALONG AND S OF WARM FRONT.
ADDITIONAL STORM DEVELOPMENT WILL BE POSSIBLE ALONG WARM AND COLD
FRONTS ASSOCIATED WITH SURFACE LOW MOVING FROM E-CNTRL SD TOWARD
CNTRL MN. ENHANCED LOW-LEVEL SHEAR AHEAD OF SURFACE LOW COUPLED
WITH THE MOISTENING/DESTABILIZING AIR MASS WILL SUPPORT SUPERCELLS
CAPABLE OF LARGE HAIL AND TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 23030.


...MEAD

[CrazyC83]

MESOSCALE DISCUSSION 0851
NWS STORM PREDICTION CENTER NORMAN OK
1242 PM CDT SUN MAY 22 2011

AREAS AFFECTED...PORTIONS OF W-CNTRL/NWRN TX INTO S-CNTRL OK

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 221742Z - 221945Z

ISOLATED TO WIDELY SCATTERED SUPERCELLS WILL LIKELY DEVELOP ALONG
THE DRYLINE BY MID-AFTERNOON. PRIMARY INITIAL THREAT WILL BE LARGE
HAIL /SOME SIGNIFICANT/. THE PROBABILITY OF ONE OR MORE WW ISSUANCES
BY 20Z IS 80 PERCENT.

17Z SUBJECTIVE SURFACE ANALYSIS PLACED DRYLINE FROM AROUND 40 E SPS
SWWD TO 60 SE MAF. RECENT VISIBLE SATELLITE IMAGERY INDICATES CU
DEEPENING ALONG AND AHEAD OF THE DRYLINE. INCIPIENT TSTM FORMATION
APPEARS PROBABLE BY 19Z AS AIR MASS HAS BECOME LARGELY UNCAPPED
BASED ON MODIFIED 12Z DRT/FWD RAOBS WITH MLCAPE AOA 4000 J/KG. THIS
EXTREME INSTABILITY COUPLED WITH 35 TO 40 KT W/SWLYS AT 500 MB WILL
BE MORE THAN SUFFICIENT FOR SUPERCELLS PRIMARILY PRODUCING VERY
LARGE HAIL.

MODEST UNCERTAINTY EXISTS OVER THE SPATIOTEMPORAL EXTENT OF THE
TORNADO THREAT. ACROSS THE CONCHO VALLEY/BIG COUNTRY...LOW-LEVEL
SHEAR SHOULD REMAIN WEAK THROUGH MOST OF THE AFTERNOON BEFORE
INCREASING NEAR AND AFTER 00Z AS MASS RESPONSE OCCURS DOWNSTREAM OF
A WRN CONUS UPPER-LEVEL TROUGH. FARTHER EAST... STRONGER LOW-LEVEL
FLOW SAMPLED IN PROFILER/VWP DATA ALONG THE I-35 CORRIDOR SHOULD
LARGELY BE MAINTAINED THROUGH THE LATE AFTERNOON AND GIVEN THE
DEGREE OF INSTABILITY WILL FAVOR A THREAT FOR TORNADOES.

..GRAMS.. 05/22/2011


ATTN...WFO...FWD...OUN...SJT...MAF...

LAT...LON 34329783 34879749 34899650 34319637 32549758 31499895
31220006 31360108 31640119 31910099 32499995 32859874
34329783

[CrazyC83]

Tornado probs 80/50. Probably PDS was discussed (80/50 is borderline) given the wording but Mead is pretty conservative.

SEL3

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 323
NWS STORM PREDICTION CENTER NORMAN OK
1255 PM CDT SUN MAY 22 2011

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

EASTERN IOWA
WESTERN ILLINOIS
EAST-CENTRAL KANSAS
NORTHERN MISSOURI

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 1255 PM UNTIL
900 PM CDT.

TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 90 STATUTE
MILES EAST AND WEST OF A LINE FROM 40 MILES NORTH NORTHWEST OF
DUBUQUE IOWA TO 25 MILES WEST SOUTHWEST OF COLUMBIA MISSOURI.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU3).

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 321...WW 322...

DISCUSSION...TSTMS ARE IN THE PROCESS OF DEVELOPING ALONG PRIMARY
COLD FRONT EXTENDING FROM N-CNTRL IA TO E-CNTRL KS AS WELL AS ALONG
GRAVITY WAVE-INDUCED SURFACE CONVERGENCE BOUNDARY FROM CNTRL IL INTO
E-CNTRL MO. AMBIENT WARM SECTOR AIR MASS IS QUITE MOIST AND
MODERATELY TO STRONGLY UNSTABLE WITH MLCAPE VALUES OF 2000-3500
J/KG. WHEN COUPLED WITH 40-50 KT OF DEEP-LAYER SHEAR AND MODERATELY
STRONG LOW-LEVEL SHEAR...THE POTENTIAL WILL EXIST FOR SUPERCELLS
CAPABLE OF DESTRUCTIVE HAIL AND TORNADOES...SOME POSSIBLY STRONG.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
600. MEAN STORM MOTION VECTOR 24030.


...MEAD

[CrazyC83]

Tornado Watch 325 coming. Extreme hail probs (like 95/95) probably coming with it. May go 60H hail there at 2000Z? Although that would still be only a Moderate Risk.

MESOSCALE DISCUSSION 0853
NWS STORM PREDICTION CENTER NORMAN OK
0106 PM CDT SUN MAY 22 2011

AREAS AFFECTED...ERN KS...NERN OK...MUCH OF SRN AND SWRN MO...NRN AR

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

VALID 221806Z - 222000Z

A TORNADO WATCH WILL BE ISSUED SHORTLY.

AN EXTREMELY UNSTABLE AIR MASS HAS DEVELOPED E OF THE DRYLINE WITH
DEWPOINTS NEAR 70 F BENEATH STEEP MID LEVEL LAPSE RATES. NEARLY ALL
CONVECTIVE INHIBITION HAS BEEN ERODED...THUS EXPECTED CU ALONG THE
DRYLINE TO ERUPT INTO INTENSE SUPERCELLS. EXTREMELY LARGE HAIL IS
LIKELY...AND ALTHOUGH LOW LEVEL SHEAR IS A BIT MARGINAL...IT WILL BE
MORE THAN SUFFICIENT FOR TORNADOES GIVEN EXTREME INSTABILITY.

..JEWELL.. 05/22/2011


ATTN...WFO...LSX...LZK...SGF...EAX...TSA...ICT...

LAT...LON 36619153 36159187 36009275 36049408 36049519 36099643
36459673 36859655 37749573 38249409 38389294 38389201
37969159 37169139 36619153

[CrazyC83]

Southeastern states.

SEL4

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 324
NWS STORM PREDICTION CENTER NORMAN OK
220 PM EDT SUN MAY 22 2011

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

NORTHERN ALABAMA
NORTHERN GEORGIA
SOUTHEAST INDIANA
CENTRAL AND EASTERN KENTUCKY
EXTREME WESTERN NORTH CAROLINA
MIDDLE AND EASTERN TENNESSEE
EXTREME SOUTHWEST VIRGINIA

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 220 PM UNTIL 900
PM EDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 115
STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES WEST
SOUTHWEST OF ROME GEORGIA TO 35 MILES NORTH NORTHEAST OF
LEXINGTON KENTUCKY. FOR A COMPLETE DEPICTION OF THE WATCH SEE
THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).

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 321...WW 322...WW 323...

DISCUSSION...SCATTERED THUNDERSTORMS HAVE BEGUN TO DEVELOP OVER A
LARGE AREA OF THE TN AND CENTRAL OH VALLEY. STRONG DAYTIME HEATING
AND AN APPROACHING MID LEVEL SHORTWAVE WILL SUPPORT CONTINUED
DEVELOPMENT THROUGH THE AFTERNOON AND EARLY EVENING. MODERATELY
STRONG MID LEVEL WINDS AND STEEP LAPSE RATES WILL PROMOTE A RISK OF
HAIL AND DAMAGING WINDS IN THE STRONGER CELLS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 26030.


...HART

[CrazyC83]

Southern tornado watch being issued now. Expect the hail numbers to be off the charts, and I would think the tornado numbers will be moderate (like 60/30).

[CrazyC83]

Tornado probs 70/40, hail 80/90.

SEL5

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 325
NWS STORM PREDICTION CENTER NORMAN OK
130 PM CDT SUN MAY 22 2011

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

NORTHWEST ARKANSAS
SOUTHEAST KANSAS
SOUTHWEST AND CENTRAL MISSOURI
EASTERN OKLAHOMA

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 130 PM UNTIL 900
PM CDT.

TORNADOES...HAIL TO 4 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 75 STATUTE
MILES EAST AND WEST OF A LINE FROM 30 MILES WEST NORTHWEST OF
JEFFERSON CITY MISSOURI TO 30 MILES SOUTH OF MUSKOGEE OKLAHOMA.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU5).

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 321...WW 322...WW
323...WW 324...

DISCUSSION...EXPLOSIVE TSTM DEVELOPMENT IS EXPECTED WITHIN THE NEXT
ONE TO TWO HOURS ALONG COLD FRONT MOVING THROUGH SERN KS AND NERN
OK. WARM SECTOR AIR MASS IS QUITE MOIST WITH DEWPOINTS IN THE LOWER
70S. WHEN COUPLED WITH STEEP MIDLEVEL LAPSE RATES...ENVIRONMENT HAS
BECOME STRONGLY TO EXTREMELY UNSTABLE WITH MLCAPE OF 3000-5000 J/KG.
THE PRESENCE OF 35-40 KT WLY DEEP-LAYER SHEAR WILL BE SUPPORTIVE OF
SUPERCELLS CAPABLE OF DESTRUCTIVE HAIL. MOREOVER...SWRN EXTENSION
OF A 30-35 KT SWLY LLJ WILL BE MAINTAINED ACROSS THE
REGION...RESULTING IN EFFECTIVE SRH VALUES OF 150-250 M2/S2 AND AN
ASSOCIATED TORNADO THREAT. A STRONG TORNADO OR TWO IS POSSIBLE.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 4 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
600. MEAN STORM MOTION VECTOR 27025.


...MEAD

[CrazyC83]

Moderate risk tomorrow as well.

SPC AC 221729

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1229 PM CDT SUN MAY 22 2011

VALID 231200Z - 241200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PORTIONS OF CENTRAL AND
NRN OK...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL/SRN PLAINS NEWD
INTO THE MIDDLE MS...TN AND OH VALLEYS AND LWR GREAT LAKES....

...SYNOPSIS...
UPPER LOW...LOCATED OVER THE UPPER MS VALLEY TODAY...WILL SHIFT
ENEWD INTO ONTARIO AND QUEBEC DURING THE FORECAST PERIOD. ASSOCIATED
SURFACE FRONT IS FORECAST TO STRETCH FROM LOWER MI SWWD THROUGH THE
MIDDLE MS VALLEY INTO SRN KS/NRN OK LATE MONDAY AFTERNOON. AN UPPER
LEVEL TROUGH WILL AMPLIFY IN THE WRN STATES AND PROGRESS RAPIDLY EWD
THROUGH THE SWRN STATES. AHEAD OF THIS TROUGH...AN UPPER
IMPULSE...CURRENTLY LOCATED OVER NV/SRN CA... WILL BE EJECTED EWD
AHEAD OF THE MAIN TROUGH AND MOVE ACROSS OK/TX MONDAY AFTERNOON.
DEEPENING TROUGH IN THE WEST SHOULD MAINTAIN DRYLINE FURTHER WEST
TOMORROW THAN TODAY AND IS EXPECTED TO EXTEND NEAR A P28-LTS-EAST OF
ABI LINE AT LATE AFTERNOON. LARGE AREA OF WARM UNSTABLE AIR MASS IS
LIKELY TO RESULT IN ANOTHER ACTIVE SEVERE WEATHER DAY ACROSS A LARGE
AREA...WITH THE INGREDIENTS ACROSS PORTIONS OF OK MOST FAVORABLE FOR
GREATER SEVERE WEATHER COVERAGE.

...CENTRAL/SRN PLAINS EWD INTO THE MIDDLE MS VALLEY...
MODELS SUGGEST CONVECTION/MCS MAY BE ONGOING PORTIONS OF SRN OK/NRN
KS AT THE START OF THE PERIOD AS STRENGTHENING LOW LEVEL JET
INTERACTS WITH QUASI-STATIONARY FRONT. EXPECT THIS ACTIVITY TO SHIFT
MOSTLY EWD WITHIN MODERATELY STRONG WLY FLOW ALOFT AS LOW LEVEL JET
VEERS INTO AR/MO. GIVEN AT LEAST MODERATE INSTABILITY AND 30-40 DEEP
LAYER SHEAR...CLUSTER MAY PRODUCE SEVERE WEATHER DURING THE
MORNING/EARLY AFTERNOON HOURS.

CONVECTION IS EXPECTED TO REINFORCE FRONT...WITH EFFECTIVE
CONVECTIVE OUTFLOW BOUNDARY LOCATED IN NRN OK. AS CONVECTION SHIFTS
EWD INTO AR/MO...AIR MASS SHOULD RECOVER QUICKLY GIVEN LARGE SOURCE
OF MOIST UNSTABLE AIR MASS SOUTH OF CONVECTION. WITH
HEATING...EXTREMELY UNSTABLE AIR MASS WILL BE IN PLACE AS UPPER
TROUGH APPROACHES FROM THE WEST DURING THE AFTERNOON. THIS WILL
RESULT IN STORMS REDEVELOPING NEAR THE OUTFLOW BOUNDARY/FRONT AND
EAST OF DRYLINE IN OK AND SRN KS. THE MOISTENED BOUNDARY LAYER FROM
OVERNIGHT CONVECTION COMBINED WITH EXTREME INSTABILITY AND 40-50 KT
DEEP LAYER SHEAR WILL BE FAVORABLE FOR SUPERCELLS WITH VERY LARGE
HAIL. THE GREATEST COVERAGE OF STORMS IS EXPECTED IN THE MODERATE
RISK AREA...AND THE MOISTENED BOUNDARY LAYER AND VEERED LOW LEVEL
WINDS ALSO SUGGEST A FEW TORNADOES...SOME STRONG...ARE ALSO
POSSIBLE. STORMS ARE EXPECTED TO DEVELOP SWD ALONG THE DRYLINE IN
NRN TX DURING THE LATE AFTERNOON HOURS...WITH VERY LARGE HAIL AND
PERHAPS A TORNADO OR TWO POSSIBLE. STORMS THAT DEVELOP IN NRN
TX/OK/SRN KS ARE EXPECTED TO SHIFT EWD OVERNIGHT AS AN MCS OR
TWO...WITH THE POTENTIAL FOR WIND DAMAGE AND HAIL INTO AR AND MO.

...TN AND OH VALLEYS...
MORNING CLUSTERS OF WEAKENING STORMS ARE EXPECTED TO MOVE EWD
ACROSS PORTIONS OF THE REGION IN THE MORNING. HOWEVER...THE STORMS
SHOULD BE LOCATED WELL EAST OF THE FRONT AND STRONG DESTABILIZATION
SHOULD OCCUR NEAR THE COLD FRONT FROM WRN OH SWWD INTO CENTRAL
INDIANA AND SRN IL BY AFTERNOON. THIS SHOULD SUPPORT RENEWED
THUNDERSTORMS DEVELOPING NEAR THE FRONT AND SHIFTING EWD THROUGH THE
OH/TN VALLEYS. THE SHEAR WILL BE SUPPORTIVE OF SUPERCELLS...WITH A
TORNADO OR TWO POSSIBLE IN THE MORE DISCRETE STORMS. HOWEVER...THE
MODELS HINT AT MORE WIDESPREAD CONVECTION DEVELOPING ALONG/AHEAD OF
THE FRONT AND SHIFTING EWD INTO THE EVENING HOURS. THIS APPEARS
REASONABLE GIVEN THE FORECAST OF DEEP WSWLY FLOW ABOVE THE BOUNDARY
LAYER...WITH WIND DAMAGE THE MOST LIKELY THREAT.

..IMY.. 05/22/2011

CLICK TO GET WUUS02 PTSDY2 PRODUCT

NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z
CURRENT UTC TIME: 1838Z (2:38PM), RELOAD THIS PAGE TO UPDATE THE TIME

[CrazyC83]

Farther south. Probs 50/40.

SEL6

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 326
NWS STORM PREDICTION CENTER NORMAN OK
150 PM CDT SUN MAY 22 2011

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

CENTRAL OKLAHOMA
NORTH-CENTRAL TEXAS

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 150 PM UNTIL 900
PM CDT.

TORNADOES...HAIL TO 4 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE
MILES EAST AND WEST OF A LINE FROM 25 MILES NORTH NORTHWEST OF
MCALESTER OKLAHOMA TO 40 MILES SOUTH SOUTHWEST OF MINERAL WELLS
TEXAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).

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 321...WW 322...WW
323...WW 324...WW 325...

DISCUSSION...ISOLATED STORM DEVELOPMENT IS ANTICIPATED ALONG THE
DRYLINE BY LATE AFTERNOON AS CONTINUED DAYTIME HEATING ERODES
REMAINING CONVECTIVE INHIBITION. 18Z FWD SOUNDING SHOWED THAT THE
WARM SECTOR IS ALREADY EXTREMELY UNSTABLE WITH MLCAPE VALUES
APPROACHING 5000 J/KG. THIS DEGREE OF INSTABILITY COUPLED WITH
35-40 KT OF DEEP-LAYER SHEAR WILL SUPPORT INTENSE SUPERCELLS CAPABLE
OF DESTRUCTIVE HAIL. THE THREAT FOR TORNADOES WILL INCREASE THIS
EVENING AS LOW-LEVEL SHEAR INTENSIFIES IN RESPONSE TO THE
DEVELOPMENT OF A SLY LLJ.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 4 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 27020.


...MEAD

[CrazyC83]

MESOSCALE DISCUSSION 0855
NWS STORM PREDICTION CENTER NORMAN OK
0149 PM CDT SUN MAY 22 2011

AREAS AFFECTED...ERN WI...NRN IL

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

VALID 221849Z - 221945Z

CONDITIONS WILL CONTINUE TO RAPIDLY EVOLVE THIS AFTERNOON AND A
TORNADO WATCH WILL LIKELY BE NEEDED FROM ERN WI INTO NRN IL.

SURFACE MAP SHOWS RELATIVELY DRY AIR IN PLACE OVER ERN WI/NRN IL
WITH DEWPOINTS ONLY IN THE 50S F. HOWEVER...MID 60S TO NEAR 70S F
BOUNDARY LAYER DEWPOINTS ARE LURKING UPSTREAM OVER SERN IA AND CNTRL
IL...AND WILL MOVE INTO THE AREA BY EVENING. ALSO AT THAT
TIME...WIND PROFILES WILL HAVE BECOME MORE FAVORABLE FOR SUPERCELLS
WITH A THREAT OF TORNADOES. THE 18Z DVN SOUNDING SHOWS VERY STEEP
LAPSE RATES ALOFT WITH MINIMAL CAPPING...ALONG WITH AMPLE DEEP LAYER
WIND FIELDS FOR ORGANIZED SEVERE.

ACTIVITY HAS FORMED ALONG THE GRAVITY WAVE OVER CNTRL IL...AND THEY
MAY BECOME BETTER ORGANIZED WITH TIME. FARTHER N... A LEAD BAND OF
CONVECTION WILL TRAVERSE WI WITH PERHAPS A MARGINAL HAIL THREAT.
HOWEVER...THE GREATEST SEVERE THREAT WILL EVOLVE OUT OF THE DRYLINE
STORMS OVER E CNTRL IA AND NRN MO...WITH TORNADOES AND VERY LARGE
HAIL AS THEY CROSS THE MS INTO WI AND IL.

..JEWELL.. 05/22/2011


ATTN...WFO...MQT...GRB...LOT...ILX...MKX...DVN...ARX...

LAT...LON 41068933 42688945 44458993 45259071 45518888 45128755
44268741 41148764 41068933

[CrazyC83]

MESOSCALE DISCUSSION 0856
NWS STORM PREDICTION CENTER NORMAN OK
0151 PM CDT SUN MAY 22 2011

AREAS AFFECTED...CNTRL/ERN IND...WRN/SRN OH...FAR NRN KY

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 221851Z - 221945Z

AT LEAST A MARGINAL THREAT OF SEVERE HAIL/DAMAGING WIND AND PERHAPS
A TORNADO IS EXPECTED THIS AFTERNOON. ALTHOUGH SEVERE STORM COVERAGE
MAY REMAIN SPORADIC GIVEN AN ILL-DEFINED SYNOPTIC-SCALE FOCUS...A WW
ISSUANCE WILL LIKELY BE NEEDED BY 20Z.

A RECENT FLARE-UP IN TSTM ACTIVITY HAS OCCURRED ALONG AND N OF THE
OH VALLEY. OVERALL ENVIRONMENTAL SETUP DOES APPEAR SLIGHTLY MORE
MARGINAL RELATIVE TO AREAS WITHIN WW 324. NEVERTHELESS...A
MODERATELY UNSTABLE AIR MASS CHARACTERIZED BY MLCAPE OF 1000 TO 2000
J/KG AND MODERATE EFFECTIVE SHEAR OF 25 TO 35 KT...WILL SUPPORT
OCCASIONAL UPDRAFT ORGANIZATION. GIVEN BROAD LARGE-SCALE ASCENT
ASSOCIATED WITH THE UPPER MS VALLEY SHORT WAVE TROUGH...TSTM
COVERAGE SHOULD CONTINUE TO INCREASE TOWARDS THE UPPER OH VALLEY.

..GRAMS.. 05/22/2011


ATTN...WFO...PBZ...RLX...CLE...JKL...ILN...DTX...LMK...IWX...
IND...

LAT...LON 38678626 39648692 41198552 41658503 41818444 41778388
40998295 40718268 39998170 39408166 38918196 38318233
38098268 38548413 38548501 38678626