Possible Severe Weather Outbreak April 2-5?

[srainhoutx]

SPC is already hinting of a potential multi day severe weather event beginning this weekend and heading into next week....

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0409 AM CDT THU MAR 31 2011

VALID 031200Z - 081200Z

...DISCUSSION...

SOME TIMING AND AMPLITUDE DIFFERENCES PERSIST AMONG GFS...ECMWF AND
ENSEMBLE MEMBERS. HOWEVER...MODELS HAVE GENERALLY CONVERGED TOWARD A
SIMILAR SOLUTION REGARDING UPPER TROUGH FORECAST TO AMPLIFY AND MOVE
INTO THE PLAINS LATE DAY 4...THEN MS/OH VALLEYS AND SERN STATES DAY
5 AND FINALLY ATLANTIC COASTAL REGION DAY 6. IT APPEARS THIS FEATURE
WILL REMAIN A PROGRESSIVE UPPER WAVE AS IT ADVANCES THROUGH THE ERN
2/3 OF THE COUNTRY.

...DAY 4...

LLJ ASSOCIATED WITH CNTRL PLAINS LEE CYCLONE WILL CONTINUE ADVECTING
RICHER GULF MOISTURE THROUGH WARM SECTOR ACROSS THE SRN-CNTRL PLAINS
AND LOWER-MID MS VALLEY. EML WILL EXPAND EWD AND EFFECTIVELY CAP
WARM SECTOR EAST OF DRYLINE OVER THE PLAINS. HOWEVER...POTENTIAL
WILL EXIST FOR IMPULSE TO EJECT EWD AHEAD OF MAIN UPPER TROUGH.
DIABATIC WARMING OF THE BOUNDARY LAYER AND DRYLINE CONVERGENCE MIGHT
BECOME SUFFICIENT FOR ISOLATED SUPERCELLS FROM KS SWD INTO OK AND
NRN TX. ADDITIONAL STORMS WILL BE MORE LIKELY AS THE COLD FRONT
ADVANCES SEWD AND INTERCEPTS THE DRYLINE FROM THE CNTRL PLAINS INTO
THE MID MS VALLEY AREA.

...DAY 5...

WIDESPREAD SEVERE STORMS ARE BECOMING INCREASINGLY PROBABLE DAY 5.
GULF MOISTURE WILL ADVECT NWD THROUGH LOWER-MID MS VALLEY...SERN
STATES AND OH VALLEY IN ASSOCIATION WITH VERY STRONG EWD MIGRATING
LLJ. MORE WIDESPREAD THUNDERSTORM DEVELOPMENT WILL BECOME PROBABLE
AS FORCING FOR DEEP ASCENT ATTENDING THE UPPER TROUGH SHIFTS EAST OF
STRONGER EML. THREAT WILL EXIST FOR SUPERCELLS AND LINE SEGMENTS
WITH TORNADOES...LARGE HAIL AND DAMAGING WIND.

...DAY 6...

SEVERE THREAT SHOULD CONTINUE THROUGH THE REMAINDER OF THE SERN
STATES AND THE MID ATLANTIC SEABOARD.

..DIAL.. 03/31/2011

[Ivanhater]

12z GFS looks like it could be a historic outbreak....Wouldn't be surprised if we see a High end threat

[EmeraldCoast93]

Interesting words from NWS offices... mainly with timing differences

NWS Mobile/Pensacola
MODEL GUIDANCE IS IN AGREEMENT ON
DEVELOPING A HIGHLY AMPLIFIED TROUGH OVER THE CENTRAL UNITED STATES
AND MOVING IT EAST THROUGH THE AREA EARLY IN THE WEEK. WHERE THE
MODELS DIFFER IS IN EXACTLY WHEN THIS TAKES PLACE. THE GFS IS MUCH
SLOWER WITH THE PASSAGE OF THE ATTENDANT COLD FRONT...NOT PUSHING
EAST OF THE AREA UNTIL TUESDAY NIGHT. THE ECMWF IS ABOUT 18 HOURS
FASTER. THE GFS ENSEMBLES ARE SPLIT ABOUT 50/50 AND THE CANADIAN IS
THE SLOWEST OF ALL GUIDANCE...NOT BRINGING THE SYSTEM THROUGH UNTIL
WEDNESDAY. NEEDLESS TO SAY...CONFIDENCE IS LOW ON THE TIMING OF THIS
SYSTEM.
WHAT THE MODELS ALL AGREE ON IS THAT THIS WILL BE A VIGOROUS SYSTEM
WITH SEVERAL INGREDIENTS IN PLACE FOR THE POTENTIAL OF A SIGNIFICANT
SEVERE WEATHER EVENT OVER THE SOUTHEAST STATES.

NWS New Orleans
THEIR IS DISAGREEMENT BETWEEN MODELS
AS TO TIMING OF THE APPROACHING SYSTEM. ECMWF IS FASTER BY ABOUT 12
HRS THAN THE GFS WHICH HAS BULK OF THE RAIN OVER THE CWA DURING THE
DAY ON TUESDAY. SEVERE STORMS ACROSS THE AREA AS THE FRONT SWINGS THRU. SPC HAS
OUTLOOKED THE AREA FOR DAY5 POTENTIAL AND DO AGREE WITH THAT. JUST
GLANCING AT INSTABILITY IT APPEARS THERE WILL BE THE POTENTIAL FOR
ROBUST UPDRAFTS WITH STEEP LAPSE RATES AND PLENTY OF CAPE. WILL
CONTINUE TO SHOW THIS POTENTIAL THRU THE HWO AND GRAPHICS.

NWS Birmingham
STILL...I QUESTION THE MOVE AS THE OLD RULE THE SLOWEST MODEL IS TOO FAST
GENERALLY DOESN`T HOLD WHEN THE NORTHERN AND SOUTHERN BRANCHES
MEET OVER ZONAL FAST FLOW. ONE MORE CONSIDERATION THAT COULD BE A
GAME-CHANGER IN MANY WAYS IS EXACTLY HOW THE SOUTHERN STREAM
HANDLES THE SOUTHERN END OF TROF AXIS...IF IT SLOWS AND BREAKS
OFF...FORMING A NEW SOUTHEASTERN STATES SURFACE LOW. I`VE WATCHED
THIS WRINKLE CLOSELY...AND AM NOT READY TO EITHER BUY INTO IT NOR
TOSS IT ASIDE AT THIS POINT.
REGARDLESS OF THESE ISSUES...THE SYSTEM WILL CERTAINLY PACK A
DECENT FIRST WEEK OF APRIL PUNCH...WITH PLENTY OF
INSTABILITY...MOISTURE...AND SHEAR TO GO AROUND. CERTAINLY WITH
THE AFOREMENTIONED TIMING DIFFERENCES...THERE WILL BE SOME
DIFFERING THREATS PERHAPS

[srainhoutx]

HPC:

AMPLIFIED TROF COMING INTO THE PLAINS DAY 3 MON AND SWEEPING
OFF THE EAST COAST BY WEDNESDAY HAS THE INGREDIENTS FOR A
WIDESPREAD SEVERE CONVECTIVE OUTBREAK. SEE SPC OUTLOOKS.

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0255 AM CDT FRI APR 01 2011

VALID 031200Z - 041200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MS VALLEY TO SRN
PLAINS...

...SYNOPSIS...
00Z GFS/ECMWF ARE IN FAIR AGREEMENT WITH THE MID-UPPER LEVEL TROUGH
MOVING INTO THE WRN U.S. ON DAY 2 WHICH WILL UNDERGO FURTHER
AMPLIFICATION AS IT PROGRESSES EWD AND EXTENDS NEWD FROM THE SRN
ROCKIES TO THE NRN PLAINS AS A POSITIVELY-TILTED TROUGH. TWO
PRIMARY SHORTWAVE TROUGHS COMPRISING THIS SYSTEM WILL REMAIN IN
PHASE...WITH ONE TRACKING EWD FROM THE NRN ROCKIES TO THE UPPER
MIDWEST...AND THE SECOND DIGGING SEWD TOWARD NM BY 12Z MONDAY.

AT THE SURFACE...AN AREA OF LOW PRESSURE INITIALLY LOCATED OVER THE
CENTRAL PLAINS SHOULD MOVE ENEWD INTO IA BY SUNDAY EVENING AND THEN
TRACK TOWARD THE WRN GREAT LAKES SUNDAY NIGHT. A TRAILING COLD
FRONT WILL ADVANCE SSEWD THROUGH THE CENTRAL AND SRN PLAINS AND
INTERSECT THE NRN EXTENT OF THE DRY LINE IN ERN KS SUNDAY AFTERNOON.
THE DRY LINE WILL EXTEND SWD THROUGH CENTRAL OK TO CENTRAL TX SUNDAY
AFTERNOON. MEANWHILE...A WARM FRONT WILL LIFT NEWD FROM THE LOWER
MO VALLEY INTO THE OH VALLEY ON DAY 2.

...OH VALLEY/SRN GREAT LAKES SWWD TO CENTRAL/SRN PLAINS...
ELEVATED TSTMS ARE EXPECTED TO BE ONGOING...ALONG AND E OF THE WARM
FRONT...FROM ERN MO N/NWWD INTO IA WITHIN THE NOSE OF A STRONG SWLY
LLJ /50-60 KT/. LOW LEVEL MOISTENING/WAA WITHIN THIS REGIME BENEATH
STEEP MIDLEVEL LAPSE RATES WILL BE PROMOTING AT LEAST AN ISOLATED
SEVERE HAIL THREAT AT 12Z SUNDAY. THIS ISOLATED SEVERE THREAT
SHOULD PERSIST THROUGH SUNDAY MORNING AS ACTIVITY ADVANCES INTO IL
ALONG NOSE OF LLJ. THIS JET WILL SHIFT EWD INTO THE LOWER OH VALLEY
SUNDAY BENEATH PLUME OF STEEP MIDLEVEL LAPSE RATES ALSO SPREADING
EWD...RESULTING IN WIDESPREAD CLOUDS/SHOWERS N OF THE WARM FRONT.
MODELS SUGGEST CONVECTION SHOULD DIMINISH IN COVERAGE/INTENSITY BY
SUNDAY AFTERNOON...GIVEN HEIGHT RISES AND LACK OF STRONGER FORCING
ALOFT NEGATING ADDITIONAL TSTM INITIATION. RE-STRENGTHENING OF THE
OH VALLEY LLJ EXPECTED SUNDAY NIGHT WILL SUPPORT AN INCREASE IN
ELEVATED TSTMS ACROSS THIS REGION INTO THE SRN GREAT LAKES.
MARGINAL INSTABILITY WITH EWD EXTENT AND INCREASING EFFECTIVE BULK
SHEAR N OF THE WARM FRONT MAY SUPPORT A FEW STRONGER STORMS...SOME
SEVERE.

MEANWHILE...THE STRONG EML OVER THE WARM SECTOR SHOULD LIMIT
DIURNAL TSTM DEVELOPMENT ALONG AND E OF THE DRY LINE THROUGH MUCH OF
THE AFTERNOON. STRONG SLY LOW LEVEL FLOW THIS PERIOD FROM THE SRN
PLAINS TO LOWER MO VALLEY WILL TRANSPORT MOISTURE NWD BENEATH A
PLUME OF STEEP MIDLEVEL LAPSE RATES RESULTING IN A CORRIDOR OF
MODERATE INSTABILITY EXTENDING EWD FROM THE DRY LINE INTO WRN AR AND
THE MID MS VALLEY. THIS COMBINED WITH EFFECTIVE BULK SHEAR /35-50
KT/ WILL SUPPORT ORGANIZED STRONG TO SEVERE /SUPERCELLULAR/ STORMS.
LARGE HAIL...DAMAGING WINDS AND INCREASING LOW LEVEL SHEAR ALONG A
SECONDARY LLJ FROM OK TO MO WILL SUPPORT A TORNADO THREAT. 00Z
ECMWF AND 21Z SREF SUGGEST ISOLATED STRONG TO SEVERE STORMS
/SUPERCELLS/ WILL BE POSSIBLE LATE SUNDAY AFTERNOON...AS THE COLD
FRONT ENCOUNTERS THE DRY LINE AND SWD ALONG THE DRY LINE WHERE
SURFACE HEATING WILL BE MAXIMIZED. TSTM COVERAGE IS EXPECTED TO
INCREASE SUNDAY NIGHT AND SPREAD E AND SE ALONG AND AHEAD OF THE
COLD FRONT. MODERATE INSTABILITY INTO THE OVERNIGHT PERIOD COMBINED
WITH BACKING SHEAR VECTORS SUGGESTS STORMS SHOULD EVOLVE INTO A
LINEAR MODE.

..PETERS.. 04/01/2011


DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0357 AM CDT FRI APR 01 2011

VALID 041200Z - 091200Z

...DISCUSSION...
00Z GFS/ECMWF REMAIN SIMILAR IN MAINTAINING AN AMPLIFIED FULL
LATITUDE TROUGH MOVING EWD ACROSS THE PLAINS AND MS/LOWER OH VALLEYS
ON DAY 4 /MON/...AND THEN ACROSS THE ERN STATES ON DAY 5 /TUE/ AS A
MORE NEGATIVELY-TILTED SYSTEM. THESE MODELS DO DIFFER IN THE TIMING
OF THIS TROUGH WITH THE ECMWF FASTER...ESPECIALLY ON DAY 5
ACCELERATING THIS TROUGH OFF THE ERN SEABOARD BY 12Z WEDNESDAY.

...DAY 4 /MON APR 4/...
MODELS MAINTAIN LIKELIHOOD FOR WIDESPREAD SEVERE STORMS FROM THE
MID-LOWER MS VALLEY INTO THE OH/TN VALLEYS AND CENTRAL GULF COAST
STATES ON DAY 4. GULF MOISTURE WILL ADVECT NWD ACROSS THIS REGION
IN ASSOCIATION WITH VERY STRONG EWD MIGRATING SLY LLJ. TSTM
ACTIVITY WILL BE SUPPORTED AS FORCING FOR DEEP ASCENT ATTENDING THE
UPPER TROUGH SHIFTS EAST OF STRONGER EML. THIS AND STRONG WIND
FIELDS WILL SUPPORT A THREAT FOR SUPERCELLS AND LINE SEGMENTS
WITH TORNADOES...LARGE HAIL AND DAMAGING WINDS.

...DAY 5 /TUE APR 5/...
DESPITE THE TIMING DIFFERENCES OF THE GFS/ECMWF...A SEVERE THREAT
SHOULD CONTINUE THROUGH THE REMAINDER OF THE SERN STATES AND THE MID
ATLANTIC SEABOARD ON TUESDAY.

..PETERS.. 04/01/2011

[PTrackerLA]

Definitely something to watch, the GFS has been ratcheting up QPF's around my area as well now showing almost 2" over a broad area which is great news but also tells me the severe threat is going up. This spring is already much busier than last spring severe weather wise for south LA looks like this trend will continue.

[Dave]

Steve, looks like we're going to be on the northern edge of this as it stands right now but still close enough to be in it.

"MODELS MAINTAIN LIKELIHOOD FOR WIDESPREAD SEVERE STORMS FROM THE
MID-LOWER MS VALLEY INTO THE OH/TN VALLEYS AND CENTRAL GULF COAST
STATES ON DAY 4. GULF MOISTURE WILL ADVECT NWD ACROSS THIS REGION
IN ASSOCIATION WITH VERY STRONG EWD MIGRATING SLY LLJ. TSTM
ACTIVITY WILL BE SUPPORTED AS FORCING FOR DEEP ASCENT ATTENDING THE
UPPER TROUGH SHIFTS EAST OF STRONGER EML. THIS AND STRONG WIND FIELDS WILL SUPPORT A
THREAT FOR SUPERCELLS AND LINE SEGMENTS WITH TORNADOES...LARGE HAIL AND DAMAGING WINDS."

NWS Indianapolis Office Forecast Discussion

ON SUNDAY A WARM FRONT WILL MOVE INTO THE AREA. 850MB WINDS
INCREASE TO AROUND 50KT DURING THE DAY PROVIDING LIFT...SO WENT
CHANCE POPS ALL AREAS. INSTABILITY DEVELOPS DURING THE AFTERNOON
SO WENT WITH ISOLATED THUNDER THEN. POTENTIAL FOR A STRONG
TEMPERATURE GRADIENT EXISTS BY LATE SUNDAY AFTERNOON...SO STUCK
WITH A MIDDLE OF THE ROAD APPROACH FOR HIGHS.

UNSTABLE AIRMASS MOVES INTO THE AREA BY MONDAY AND 850 JET REMAINS
AROUND 50KT. THE COLD FRONT MOVES INTO THE AREA ON MONDAY
PROVIDING ADDITIONAL LIFT. PLENTY OF MOISTURE AVAILABLE LEADS TO
LIKELY POPS ALL AREAS BY MONDAY. DEPENDING ON THE EXACT TIMING OF
THE COLD FRONT SEVERE WEATHER LOOKS TO STILL BE A THREAT MONDAY
WITH INSTABILITY...SHEAR...AND MOISTURE ALL PRESENT. WILL CONTINUE
TO HIGHLIGHT IN HWO.

NWS Louisville KY Forecast Discussion

THE MORE SIGNIFICANT TIME FRAME FOR SHOWERS AND THUNDERSTORMS REMAINS
MONDAY AND MONDAY NIGHT. WITH THE FORECAST AREA IN THE WARM SECTOR
ON SUNDAY TEMPS RISE INTO THE MID TO UPPER 70S. STRONG SOUTHWESTERLY
WINDS WILL ADVECT IN MOIST GULF AIR WITH PWATS RISING TO OR ABOVE
1.5"...OVER 2 STANDARD DEVIATIONS ABOVE CLIMATOLOGY. ADDITIONALLY A
60+ KNOT LLJ WILL DEVELOP MONDAY EVENING. ALL THIS POINTS TO STRONG
TO SEVERE STORMS DEVELOPING ON MONDAY. AS MENTIONED IN THE PREVIOUS
DISCUSSION...SUPERCELL DEVELOPMENT WILL BE POSSIBLE AHEAD OF THE
COLD FRONT WITH QLCS DEVELOPMENT ALONG THE FRONT. WITH THE HIGH
MOISTURE CONTENT OF THE ATMOSPHERE VERY HEAVY RAIN WILL BE POSSIBLE
WITH THE POTENTIAL FOR SOME FLASH FLOODING ALONG WITH THE STRONG TO
SEVERE STORMS. THE FORECAST SHOULD BE MONITORED CLOSELY FOR CHANGES
IN TIMING AND DEVELOPMENT OF THIS SYSTEM OVER THE COMING DAYS.

===================
Will be watching from here both local & regional esp Sunday night thru Monday night. Get anything send it on through to me here.

[CrazyC83]

Looks like Monday will be the day of the most activity. Models still don't have the greatest handle on it though, at least the degree of activity.

[Dave]

Some activity tonight but associated with a cool front dropping down from the NW...

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
733 PM EDT FRI APR 1 2011

THE NATIONAL WEATHER SERVICE IN INDIANAPOLIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
WEST CENTRAL HENDRICKS COUNTY IN CENTRAL INDIANA...
NORTHERN PUTNAM COUNTY IN WEST CENTRAL INDIANA...

* UNTIL 815 PM EDT

* AT 724 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL. THIS
STORM WAS LOCATED 14 MILES NORTH OF GREENCASTLE...OR 14 MILES SOUTH
OF CRAWFORDSVILLE...AND MOVING SOUTHEAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
GROVELAND...FILLMORE AND NORTH SALEM AROUND 745 PM EDT...

[Dave]

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT SAT APR 02 2011

VALID 031200Z - 041200Z

...THERE IS A SLGT RISK OF SVR TSTMS SUNDAY AFTERNOON AND NIGHT FROM
THE MIDWEST/LOWER OH VALLEY TO THE SRN PLAINS...

...SYNOPSIS...
MODELS REMAIN IN FAIRLY GOOD AGREEMENT SHOWING A FULL LATITUDE
TROUGH AMPLIFYING/DEVELOPING INTO THE CENTRAL U.S. DURING DAY
2...WITH THE 12Z ECMWF/00Z GFS FASTER WITH EWD PROGRESSION THAN THE
WRF-NAM. BY 12Z MONDAY...A POSITIVELY-TILTED TROUGH SHOULD EXTEND
FROM THE UPPER MS VALLEY TO THE SRN HIGH PLAINS. 60-90 METER 500 MB
HEIGHT FALLS ARE EXPECTED FROM OK/KS TO IA/NRN IL DURING THE LATTER
HALF OF THE FORECAST PERIOD. SWLY MIDLEVEL WINDS WILL STRENGTHEN TO
50-60 KT FROM THE SRN ROCKIES TO THE LOWER MO VALLEY AND MIDWEST BY
SUNDAY AFTERNOON...WITH A FURTHER INCREASE SUNDAY NIGHT TO 70-90 KT
FROM THE SRN PLAINS TO LOWER OH VALLEY.

AT THE SURFACE...MODELS HAVE TRENDED NORTH WITH THE INITIAL POSITION
OF LOW PRESSURE AT 12Z SUNDAY...WITH THIS FEATURE LOCATED OVER SERN
SD. THIS LOW WILL TRACK EWD INTO NERN IA BY 04/00Z...AND THEN REACH
THE CENTRAL GREAT LAKES BY 12Z MONDAY. A TRAILING COLD FRONT WILL
ADVANCE SSEWD THROUGH THE CENTRAL AND SRN PLAINS...AND INTERSECT AND
OVERTAKE A DRY LINE FROM ERN KS THROUGH CENTRAL OK TO NRN TX FROM
SUNDAY AFTERNOON TO EARLY MONDAY MORNING. THE NRN EXTENT OF THE
COLD FRONT WILL PROCEED ESEWD THROUGH THE LOWER MO VALLEY REACHING
LOWER MI TO THE OZARKS BY THE END OF THE FORECAST PERIOD.
MEANWHILE...A WARM FRONT WILL LIFT NEWD FROM THE LOWER MO VALLEY
THROUGH THE OH VALLEY TO LOWER GREAT LAKES BY SUNDAY NIGHT.

...SRN PLAINS TO THE MIDWEST/LOWER OH VALLEY...
SLY LOW LEVEL WINDS WILL MAINTAIN MOISTURE RETURN FROM THE SRN
PLAINS THROUGH THE LOWER MO TO LOWER OH VALLEY DURING DAY 2...
BENEATH A STRONG EML/CAP. THIS CAP WILL LIMIT TSTM DEVELOPMENT
THROUGH MUCH OF THE DAY...WITH MODELS SUGGESTING TSTM DEVELOPMENT
WILL BE LIKELY ALONG THE COLD FRONT AS IT ADVANCES INTO NRN/CENTRAL
IL...NRN MO AND INTERSECTS THE DRY LINE IN NERN-ERN KS MID-LATE
SUNDAY AFTERNOON. MODERATE INSTABILITY...STRENGTHENING DEEP LAYER
SHEAR AND STEEP LAPSE RATES WILL SUPPORT ORGANIZED SUPERCELLULAR
STORMS PRODUCING A FEW TORNADOES...LARGE HAIL /SOME SIGNIFICANT/ AND
DAMAGING WINDS. A SECONDARY LLJ IS EXPECTED TO INCREASE TO 45-65 KT
FROM OK TO MO/IL SUNDAY EVENING...FURTHER ENHANCING LOW LEVEL SHEAR
FOR AN INCREASED TORNADO THREAT. AS THE COLD FRONT ADVANCES SWD
OVERNIGHT...STRONG WIND FIELDS COUPLED WITH MODERATE INSTABILITY
WILL SUPPORT A SEVERE WEATHER THREAT PERSISTING WELL AFTER
DARK...ESPECIALLY ACROSS MO/NRN AR TO LOWER OH VALLEY.

UNCERTAINTY EXISTS IN THE GUIDANCE FOR WHETHER TSTMS INITIATE SWD
ALONG THE DRY LINE...S OF THE KS BORDER...THROUGH OK TO NRN TX. THE
00Z WRF-NAM/21Z ETAKF MEMBER OF THE SREF/12Z ECMWF DO NOT INITIATE
ACROSS THESE AREAS...WHILE 00Z GFS TO SOME EXTENT AND THE EACH OF
THE 21Z WRF-ARW MEMBERS OF THE SREF SUGGEST STORMS DO FORM INTO OK/N
TX SUNDAY AFTERNOON. DESPITE THESE DIFFERENCES...STEEP MIDLEVEL
LAPSE RATES /8-9 C PER KM/... MODERATE INSTABILITY AND STRENGTHENING
BULK SHEAR TO 50 KT INDICATES A SLIGHT RISK REMAINS WARRANTED WITH
SWD EXTENT. IF STORMS DEVELOP...THEN THE POTENTIAL WILL EXIST FOR
LARGE HAIL...SOME SIGNIFICANT...PRIOR TO THE COLD FRONT REACHING
THIS REGION AND PROGRESSING SWD INTO TX.

...SRN GREAT LAKES REGION...
MODELS SUGGEST ELEVATED TSTMS WILL BE POSSIBLE EARLY IN THE FORECAST
PERIOD /SUNDAY MORNING/ ACROSS THE UPPER MS VALLEY WITHIN THE NOSE
OF A STRONG SWLY LLJ WHERE WAA WILL SUPPORT THIS ACTIVITY.
STRENGTHENING WSWLY MIDLEVEL WINDS ACROSS THE UPPER GREAT LAKES AND
THE LLJ SHIFTING EWD INTO THE OH VALLEY SHOULD MAINTAIN SUFFICIENT
UVVS FOR CONTINUED CONVECTION/EMBEDDED TSTM DEVELOPMENT TOWARD LOWER
MI BY SUNDAY AFTERNOON. DESPITE EFFECTIVE BULK SHEAR SUFFICIENT FOR
ORGANIZED STORMS...WEAK INSTABILITY SHOULD LIMIT THE OVERALL SEVERE
WEATHER THREAT WITH THIS ELEVATED ACTIVITY.

...CENTRAL TX...
FARTHER S...THE POTENTIAL WILL EXIST FOR TSTM DEVELOPMENT LATE IN
THE FORECAST PERIOD AS THE COLD FRONT ADVANCES SWD INTO THIS REGION.
MODERATE INSTABILITY AND EFFECTIVE BULK SHEAR 30-40 KT SUGGESTS
ORGANIZED STORMS WILL BE POSSIBLE. UNCERTAINTY IN STORM INITIATION
THIS FAR SOUTH AMONGST THE MODEL SOLUTIONS...AND THE MODELS THAT DO
INITIATE OVER THIS AREA SUGGEST THE TIMING IS AFTER 04/03-06Z.
GIVEN THESE FACTORS...ONLY LOW SEVERE PROBABILITIES /5 PERCENT/ ARE
WARRANTED AT THIS TIME.

..PETERS.. 04/02/2011

[Dave]

Day 3



SPC AC 020737

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0237 AM CDT SAT APR 02 2011

VALID 041200Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM E TX TO THE CENTRAL GULF
COAST STATES AND NWD THROUGH THE TN/OH VALLEYS...

...E TX TO CENTRAL GULF COAST STATES NWD TO TN/OH VALLEYS...
THE 00Z GFS IS NOW FASTER THAN THE 00Z ECMWF WITH THE PROGRESSION OF
THE CENTRAL PLAINS TROUGH ON MONDAY ACROSS AND E OF THE MS VALLEY
REGION. IN ADDITION TO THESE TIMING DIFFERENCES...THE GFS INDICATED
STRONGER FORCING FOR ASCENT ACROSS THE TN/OH VALLEYS...WHILE THE
ECMWF INDICATED STRONGEST FORCING FOR ASCENT SPREADING ACROSS THE
LOWER MS VALLEY/CENTRAL GULF COAST STATES MONDAY NIGHT WITH A MORE
SWD TRACKING SHORTWAVE TROUGH.

EACH MODEL SHOWED STRONG BAROCLINICITY AS A COLD FRONT ADVANCES EWD
ACROSS THE OH/TN AND LOWER MS VALLEYS...WITH THE GFS AGAIN FASTER
WITH EWD PROGRESSION SHOWING THE FRONT REACHING THE ERN SEABOARD BY
12Z TUESDAY. DESPITE THE AFOREMENTIONED DIFFERENCES BETWEEN THE GFS
AND ECMWF...THIS TROUGH WILL UNDERGO STRENGTHENING AS IT BECOMES
NEUTRALLY ORIENTED...SUPPORTING INCREASING SWLY MIDLEVEL WINDS
/60-80 KT/ FROM TX/LOWER MS VALLEY TO THE TN/OH VALLEYS...WITH
FURTHER STRENGTHENING /90-100 KT/ MONDAY NIGHT AS THE FLOW BACKS TO
SLY. IN THE LOW LEVELS...A 50-60 KT SSWLY LLJ FROM THE LOWER MS TO
LOWER OH VALLEYS WILL SUPPORT MOISTURE SPREADING NWD ACROSS THE WARM
SECTOR.

TSTMS WILL BE LIKELY AS THE COLD FRONT ENCOUNTERS THE DESTABILIZING
AIR MASS AND FORCING FOR ASCENT INCREASES WITH THE EWD PROGRESSION
OF THE MID-UPPER LEVEL TROUGH. THE GREATEST INSTABILITY IS EXPECTED
FROM THE TN VALLEY SWD. DEEP LAYER SHEAR VECTORS ORIENTED MAINLY
PARALLEL TO THE COLD FRONT SUGGEST A LINEAR STORM MODE WITH BOWING
SEGMENTS LIKELY. HOWEVER...THE STRENGTH OF THE BULK SHEAR /40-55
KT/ MAY SUPPORT EMBEDDED SUPERCELL STRUCTURES WITHIN THE QLCS.
ALTHOUGH INSTABILITY WILL TEND TO BE MARGINAL WITH NWD EXTENT...THE
STRENGTH OF THE DEEP LAYER AND LOW LEVEL SHEAR SHOULD OVERCOME THAT
LIMITING FACTOR AND SUPPORT MAINLY A DAMAGING WIND THREAT ACROSS THE
OH VALLEY.

IF THE ECMWF IS CORRECT...THEN THERE WILL BE A SEVERE WEATHER THREAT
INTO THE LATTER HALF OF THE FORECAST PERIOD FROM THE LOWER MS VALLEY
TO THE CENTRAL GULF COAST STATES.

..PETERS.. 04/02/2011

[cycloneye]

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT SAT APR 02 2011
VALID 031200Z - 041200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MIDWEST/MIDDLE MS
VALLEY TO THE SOUTH-CENTRAL PLAINS...

...MIDWEST/MIDDLE MS RIVER VALLEY TO SOUTH-CENTRAL PLAINS...
AN UPPER TROUGH...CURRENTLY OVER THE PACIFIC NORTHWEST...WILL
AMPLIFY/ADVANCE SOUTHEASTWARD IN A POSITIVE-TILT FASHION FROM THE
NORTHERN/CENTRAL ROCKIES EARLY SUNDAY TO THE UPPER MIDWEST AND
CENTRAL/SOUTHERN HIGH PLAINS BY LATE SUNDAY NIGHT. BENEATH A STRONG
ELEVATED MIXED LAYER/CAP...LOW LEVEL MOISTURE WILL AGGRESSIVELY
RETURN NORTHEASTWARD DURING THE DAY WITH AID OF A 50-70 KT
SOUTHWESTERLY LOW LEVEL JET. GENERALLY LOWER 60S F SURFACE DEWPOINTS
WILL BECOME ESTABLISHED BY MID/LATE AFTERNOON WITHIN THE PRE-COLD
FRONTAL WARM SECTOR ACROSS THE MIDWEST/LOWER MO VALLEY.

THE AFOREMENTIONED CAP SHOULD PRECLUDE SURFACE BASED TSTM
DEVELOPMENT THROUGH MUCH OF THE AFTERNOON. THAT SAID...INITIAL DEEP
CONVECTIVE DEVELOPMENT SEEMS PROBABLE BY LATE AFTERNOON/EARLY
EVENING IN VICINITY OF THE COLD FRONT ACROSS SOUTHEAST IA/NORTHWEST
IL AND NORTHERN MO...SOUTHWESTWARD TO NEAR A TRIPLE POINT/DRYLINE
INTERSECTION ACROSS EAST-CENTRAL/SOUTH-CENTRAL KS.

WITH MODERATE INSTABILITY/VERY STEEP LAPSE RATES ACROSS THE WARM
SECTOR...STRONG DEEP LAYER SHEAR AMID 50-60 KT SOUTHWESTERLY MID
LEVEL FLOW WILL SUPPORT AN INITIAL MODE OF SUPERCELLS CAPABLE OF
LARGE HAIL AND SOME TORNADOES...WITH THE RELATIVELY GREATEST
PROBABILITY OF TORNADOES APPEARING TO BE ACROSS PORTIONS OF FAR
EASTERN IA AND NORTHERN IL/NORTHEAST MO. A DAMAGING WIND THREAT WILL
UNFOLD AS WELL DURING THE EARLY/MID EVENING HOURS AS STORMS
CONGEAL/BOWS EVOLVE AMIDST NOCTURNALLY REINVIGORATED FLOW WITHIN THE
LOWEST FEW KM /70+ KT AT 850 MB/. WHILE A VERY STRONG WIND FIELD
WILL REMAIN FAVORABLE FOR SUSTAINED SUPERCELLS OR MORE LIKELY FAST
MOVING QUASI-LINEAR CONVECTION/BOWS SUNDAY NIGHT...MODEST BOUNDARY
LAYER MOISTURE/ASSOCIATED DECOUPLING IMPLIES AN INCREASINGLY MORE
ISOLATED/MARGINAL SEVERE THREAT BY LATE EVENING/OVERNIGHT ACROSS THE
MIDWEST.

FARTHER S/SW ACROSS THE SOUTH-CENTRAL PLAINS...DEEP CONVECTIVE
INITIATION PRE-EARLY EVENING/ROUGHLY PRE-03Z IS QUITE UNCERTAIN AMID
A STRONG ELEVATED MIXED LAYER/STOUT CAP. IN TERMS OF NUMERICAL
GUIDANCE...ONLY SOME WRF-ARW MEMBERSHIP OF THE 09Z SREF SUPPORTS
ISOLATED TSTM DEVELOPMENT IN VICINITY OF THE NORTH-SOUTH ORIENTED
DRYLINE ACROSS CENTRAL OK/NORTH TX...WITH OTHER/TRADITIONAL
DETERMINISTIC GUIDANCE INDICATIVE OF LITTLE OPPORTUNITY FOR PRE-DARK
INITIATION. IF STORMS DO INDEED FORM IN VICINITY OF THE DRYLINE
DURING THE LATE AFTERNOON/EARLY EVENING...RELATIVELY STRONG
INSTABILITY/HIGHLY FAVORABLE SHEAR PROFILES WOULD SUPPORT SUPERCELLS
CAPABLE OF VERY LARGE HAIL...WITH A TORNADO THREAT PROBABLY LIMITED
BY A RELATIVELY WELL-MIXED BOUNDARY LAYER. THE MOST LIKELY SCENARIO
IS FOR ISOLATED TSTMS TO DEVELOP LATE IN THE PERIOD AS THE SOUTHEAST
ADVANCING COLD FRONT OVERTAKES THE DRYLINE.
..GUYER.. 04/02/2011

[CrazyC83]

I'm still not too sure about tomorrow. I think we might have to wait until Monday.

[WeatherGuesser]

SPC AC 030558

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT SUN APR 03 2011

VALID 031200Z - 041200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF ERN KS AND NW
MO...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE MID-MO
VALLEY...CNTRL PLAINS...SRN PLAINS...WRN OZARKS AND WRN GREAT
LAKES...

...SEVERE WEATHER EVENT EXPECTED FROM ERN KS NEWD ACROSS NRN MO INTO
WRN AND NRN IL THIS AFTERNOON AND EVENING...

...MID-MO VALLEY/CNTRL PLAINS/MID-MS VALLEY/WRN GREAT LAKES...
AN UPPER-LEVEL TROUGH WILL MOVE INTO THE NRN PLAINS AND CNTRL
ROCKIES TODAY. WELL AHEAD OF THE SYSTEM...A POWERFUL 65 TO 80 KT
LOW-LEVEL JET WILL BE IN PLACE ACROSS THE MID-MO VALLEY AND LOWER OH
VALLEY THIS AFTERNOON. THE LOW-LEVEL JET WILL RAPIDLY TRANSPORT
MOISTURE NEWD INTO THE SLIGHT RISK AREA BY MID-AFTERNOON WITH SFC
DEWPOINTS LIKELY REACHING INTO THE MID 60S F FROM ERN KS NEWD TO WRN
IL. THE MOIST AIRMASS SHOULD ALLOW MODERATE INSTABILITY TO DEVELOP
ACROSS A BROAD AREA AHEAD OF A FAST-MOVING COLD FRONT. AS THE
CAPPING INVERSION WEAKENS AND LOW-LEVEL CONVERGENCE INCREASES ALONG
THE FRONT...NUMEROUS STRONG TO SEVERE THUNDERSTORMS SHOULD INITIATE
WITH A BROKEN LINE DEVELOPING DURING THE LATE AFTERNOON.

FORECAST SOUNDINGS AT 21Z SUGGEST THE STRONGEST INSTABILITY WILL BE
LOCATED IN ERN KS AND WRN MO WHERE MLCAPE VALUES ARE FORECAST TO
REACH THE 2500 TO 3500 J/KG RANGE. IN ADDITION...A PLUME OF STEEP
MID-LEVEL LAPSE RATES IS FORECAST TO NOSE INTO ERN KS AND NW MO
WHERE DEEP LAYER SHEAR SHOULD BE QUITE STRONG. THIS ENVIRONMENT WILL
LIKELY SUPPORT SUPERCELL DEVELOPMENT WITH A WIDESPREAD THREAT FOR
LARGE HAIL ESPECIALLY ACROSS ERN KS AND NW MO WHERE A MODERATE RISK
AREA HAS BEEN OUTLOOKED. VERY LARGE HAIL WILL BE POSSIBLE WITH THE
MORE DOMINATE SUPERCELLS THAT REMAIN DISCRETE. TORNADOES WILL ALSO
BE POSSIBLE WITH THE BETTER-ORGANIZED SUPERCELLS. THE TORNADO THREAT
MAY BE GREATEST NEWD ACROSS NRN MO INTO WRN AND NRN IL WHERE THE
STORMS WILL HAVE ACCESS TO GREATER LOW-LEVEL SHEAR. IF DISCRETE
ROTATING STORMS CAN PERSIST INTO THE EARLY EVENING WHEN THE
LOW-LEVEL JET IS FORECAST TO STRENGTHEN...THEN AN ISOLATED STRONG
TORNADO WILL BE POSSIBLE. DUE TO THE STRONG LOW-LEVEL FLOW OF 60 TO
70 KT AND BECAUSE OF THE AMOUNT OF INSTABILITY FORECAST...WIND
DAMAGE COULD BE WIDESPREAD FROM ERN KS NEWD ACROSS NRN MO INTO NW IL
ESPECIALLY IF A NEARLY CONTINUOUS LINE OF INTENSE STORMS DEVELOPS
DURING THE EARLY EVENING.

...SRN PLAINS/WRN OZARKS...
MOISTENING OF THE AIRMASS ACROSS THE SRN PLAINS WILL CONTINUE TODAY
AS THE SRN END OF A WELL-DEFINED LOW-LEVEL JET MOVES EWD ACROSS THE
REGION. MODERATE INSTABILITY IS FORECAST BY MID TO LATE AFTERNOON
FROM CNTRL AND NORTH TX EXTENDING NWD INTO CNTRL AND ERN OK WHERE
FORECAST SOUNDINGS SHOW MLCAPE VALUES AROUND 2500 J/KG. IN SPITE OF
THE INSTABILITY...A CAPPING INVERSION WILL LIKELY REMAIN IN PLACE
FOR MUCH OF THE AFTERNOON AND EVENING SUPPRESSING CONVECTIVE
DEVELOPMENT. SEVERAL MODEL FORECASTS INITIATE STORMS IN NE OK AND NW
AR DURING THE LATE EVENING WITH STORMS EXPANDING SWWD ALONG A COLD
FRONT DURING THE OVERNIGHT PERIOD. THE MODERATE INSTABILITY...STEEP
MID-LEVEL LAPSE RATES AND STRONG DEEP LAYER SHEAR SHOULD BE
SUFFICIENT FOR A LARGE HAIL AND WIND DAMAGE THREAT. AFTER
MIDNIGHT...ISOLATED THUNDERSTORM DEVELOPMENT COULD OCCUR SWWD ACROSS
CNTRL AND NORTH TX AS THE COLD FRONT MOVES INTO THE REGION FROM THE
NORTHWEST. FORECAST SOUNDINGS IN CNTRL AND NORTH TX AT 09Z TO 12Z
SUGGEST DEEP LAYER SHEAR MAY BE STRONG ENOUGH FOR A MARGINAL WIND
DAMAGE AND HAIL THREAT.

..BROYLES/GARNER.. 04/03/2011

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
CURRENT UTC TIME: 0804Z (3:04AM), RELOAD THIS PAGE TO UPDATE THE TIME

[WeatherGuesser]

[wx247]

This is the first time in a quite a while I have seen a pretty big discrepancy between the SPC and our local NWS office. SPC has our area in a slight risk with far NW sections in a moderate risk. Our local office only has far NW portions of the area under a risk for any type of severe weather. I wonder who will win...

[Dave]

Because we're the western most county for our weather office KILN Wilmington OH we actually work off of 3 offices instead of just 1 those being Indy, Louisville and Wilmington. All 3 are leaning more towards the active weather for us coming in late tonight & tomorrow with damaging straight line winds being the key factor however there is a risk of tornadoes with it.

Red flag warnings are rarely issued up here but all counties to my south are now under them. Wind advisories have already been posted here. Timing will be a factor here also, if the front comes through late tonight, activity may decrease somewhat but if it rolls through at dawn that's not good. Our worst times for severe weather in this area are either late afternoon or dawn.

See what develops through the day today....headed for 75 degrees...first time this year. Normally I'd welcome that but the heating is going to provide lift with it + moisture coming in from the gulf so it may get interesting around here later on.

[CrazyC83]

MDT risk is for hail. Greatest tornado risk is farther north and east.

[Dave]

Temp 75, Winds ESE gusting to 42 now & sunshine. It's going to be early morning or tomorrow before we see anything here from what it looks like right now.

Latest Visible Satellite of this region...let's put it on the correct server first...helps to see it.

[srainhoutx]

I agree Dave. Capping issue today have squashed any development, for now. Tonight into tomorrow will likely be a different story. I do think storms will be linear for the most part and wind and hail damage probably the primary threat. We will see. Oh, and Childress, TX has reached 100F just behind the dryline.

[Dave]

I agree Steve on the linear part and so does NWS Indianapolis...from the county to my west (they're under the Indy district); county to my south is in the NWS Louisville district, and I'm in Wilmington...try that for a mix.

Only 100F A little more up here and I'll see 80...up to 76 now.

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
328 PM EDT SUN APR 3 2011

INZ021-028>031-035>049-051>057-060>065-067>072-041930-
CARROLL-WARREN-TIPPECANOE-CLINTON-HOWARD-FOUNTAIN-MONTGOMERY-
BOONE-TIPTON-HAMILTON-MADISON-DELAWARE-RANDOLPH-VERMILLION-PARKE-
PUTNAM-HENDRICKS-MARION-HANCOCK-HENRY-VIGO-CLAY-OWEN-MORGAN-
JOHNSON-SHELBY-RUSH-SULLIVAN-GREENE-MONROE-BROWN-BARTHOLOMEW-
DECATUR-KNOX-DAVIESS-MARTIN-LAWRENCE-JACKSON-JENNINGS-
328 PM EDT SUN APR 3 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL INDIANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

STRONG AND GUSTY WINDS WILL BE ACROSS THE AREA THIS AFTERNOON AND
EVENING...WITH GUSTS UP TO 57 MPH POSSIBLE.

THUNDERSTORMS WILL DEVELOP TONIGHT...MAINLY AFTER MIDNIGHT. SOME OF
THE STORMS MAY BE SEVERE...MAINLY AFTER MIDNIGHT. DAMAGING WINDS
AND HEAVY RAIN ARE THE PRIMARY THREATS...BUT LARGE HAIL AND
ISOLATED TORNADOES ARE POSSIBLE AS WELL. LIGHTNING IS A THREAT
FROM ANY THUNDERSTORM.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

THUNDERSTORMS WILL MOVE ACROSS THE AREA ON MONDAY. SOME OF
THE STORMS MAY BE SEVERE...MAINLY DURING THE MORNING INTO EARLY
AFTERNOON. DAMAGING WINDS AND HEAVY RAIN ARE THE PRIMARY
THREATS...BUT LARGE HAIL AND ISOLATED TORNADOES ARE POSSIBLE AS
WELL.

GUSTY WINDS WILL CONTINUE DURING THE DAYLIGHT HOURS MONDAY THROUGH
WEDNESDAY.

THUNDERSTORMS ARE POSSIBLE AGAIN THURSDAY THROUGH SUNDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATE TONIGHT AND MONDAY MORNING.

&&