[snowflake22]

MDT Risk has been greatly expanded into NE Kansas and the Oklahoma City area. The southern extent has been adjust southward, as well. The 15% Hatched Area comprises the northern portion of my highlighted area.

http://www.spc.noaa.gov/products/activity_loop.gif

I would not preclude a special High Risk later...

[snowflake22]

SPC AC 261255

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0755 AM CDT SUN APR 26 2009

VALID 261300Z - 271200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF TX...OK...AND
KS...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA
FROM S CNTRL TX INTO THE LWR MO/MID MS VLYS...

...SYNOPSIS...
A SERIES OF SPEED MAXIMA EJECTING NEWD ON ERN SIDE OF SLOWLY-
PROGRESSIVE WRN U.S. TROUGH WILL PRODUCE MULTIPLE EPISODES OF SVR
TSTMS OVER A FAIRLY BROAD SWATH OF THE CNTRL AND S CNTRL U.S.
THROUGH EARLY MON.

MAIN UPR VORT NOW OVER WY/CO SHOULD CONTINUE NE INTO THE DAKOTAS/NEB
LATER TODAY AS TRAILING/LOOSELY-ASSOCIATED SRN IMPULSE NOW IN NM
REACHES W TX. THE LATTER FEATURE SHOULD CONTINUE NE INTO THE LWR MO
VLY/WRN OZARKS BY 12Z MON...WHILE ADDITIONAL IMPULSES OF MORE SRN
ORIGIN MOVE ENE ACROSS WRN/CNTRL TX.

AT LWR LVLS...ERN PART OF MAIN SYNOPTIC SCALE FRONT NOW EXTENDING
FROM SW KS TO THE MID MS VLY SHOULD SURGE NE INTO WI AND THE UPR GRT
LKS BY EARLY MON AS A SFC WAVE DEVELOPS OVER SE NEB AND MOVES NE IN
ASSOCIATION WITH LEAD UPR IMPULSE. IN THE WAKE OF THE WAVE...
EXPECT TRAILING WRN PART OF THE FRONT WILL ACCELERATE SE ACROSS
WRN/NRN KS AND THE OK/NRN TX PANHANDLE REGION EARLY MON. FARTHER
S...STRONG/PERSISTENT SW FLOW ALOFT WILL MAINTAIN LEE LOW AND
TROUGH/DRY LINE OVER THE SRN HI PLNS.

...SRN PLNS INTO CNTRL KS...
SLOW EWD PROGRESSION OF WRN STATES TROUGH...AND ASSOCIATED ARRAY OF
SPEED MAXIMA...WILL MAINTAIN A BROAD CURRENT OF 55-65 KT MID LVL
SSWLY FLOW OVER MOST THE SRN AND CNTRL PLNS THROUGH THE PERIOD.
THUS...DEEP SHEAR WILL BE FAVORABLE FOR SUSTAINED STORMS/ SUPERCELLS
OVER A WIDE REGION. BUT SATELLITE LOOPS SUGGEST THE PRESENCE OF
NUMEROUS WEAK SHORT WAVE DISTURBANCES WITHIN THIS FLOW...IN ADDITION
TO THE MORE OBVIOUS ONES MENTIONED IN THE SYNOPSIS. THESE LIKELY
WILL MODULATE STORM DEVELOPMENT AND EVOLUTION ON THE MESOSCALE...AND
WILL ADD CONSIDERABLE COMPLEXITY TO THE GENERAL SCENARIO OUTLINED
BELOW.

ONE APPARENT IMPULSE...NOW IN CNTRL OK...APPEARS RESPONSIBLE IN PART
FOR RECENT INCREASE IN STORMS ALONG ADVANCING WARM FRONT IN CNTRL
KS. EXPECTED THIS ACTIVITY TO INCREASE BOTH NEWD AND SWWD ALONG
FRONT THROUGH THE MORNING AS STRONG/MOIST SLY LLJ CONTINUES TO
IMPINGE ON BOUNDARY.

A BIT LATER THIS MORNING THROUGH EARLY THIS AFTN...EXPECT THAT
ASCENT WITH STRONGER NM IMPULSE WILL HELP INITIATE STORMS ALONG LEE
TROUGH/DRY LINE FROM THE ERN TX PANHANDLE/NW OK SSW TO THE PERMIAN
BASIN. SFC HEATING ON WRN EDGE OF EXTENSIVE LOW CLOUD FIELD...AND
WEAK HEIGHT FALLS/MID LVL COOLING...SHOULD ALLOW THIS ACTIVITY TO
INCREASE IN COVERAGE/STRENGTH THROUGH LATE THIS AFTN/EVE.

COMBINATION OF STRONG INSTABILITY /SBCAPE TO 2000 J PER KG/ AND RICH
MOISTURE /PW 1.00-1.25 INCHES/ WITH 40-50 KT DEEP SWLY SHEAR SHOULD
SUPPORT SCTD SUSTAINED SUPERCELLS WITH SVR HAIL AND WIND.
INITIALLY...BACK-VEER PATTERN TO WIND PROFILES ACROSS THE SRN HI
PLNS /E.G AS IN 12Z MAF RAOB/ WILL COMPLICATE STORM STRUCTURE/ FAVOR
LINE SEGMENTS. ALTHOUGH THIS MAY LIMIT POTENTIAL FOR
TORNADOES...GIVEN STRENGTH OF SHEAR AND QUALITY OF MOIST INFLOW...AT
LEAST A CONDITIONAL TORNADO THREAT WILL EXIST.

BY LATE AFTN OR EARLY EVE...EXPECT THAT THE STORMS WILL HAVE EVOLVED
INTO SEVERAL LOOSELY-ORGANIZED CLUSTERS EXTENDING FROM CNTRL/SRN KS
THROUGH WRN/CNTRL OK INTO NRN/W CNTRL AND SW TX. EMBEDDED
SUPERCELLS WITHIN THESE CLUSTERS WILL CONTINUE TO POSE A THREAT FOR
SVR HAIL/WIND AND TORNADOES. THE TORNADO THREAT MAY ONCE AGAIN
INCREASE TOWARD SUNSET AND LATER AS SLY LLJ STRENGTHENS TO AOA 50
KTS.

GIVEN THE MAGNITUDE OF THE SHEAR AND THE BREADTH/QUALITY/STRENGTH OF
THE MOIST INFLOW...THE SVR THREAT MAY CONTINUE THROUGH LATE
TONIGHT/EARLY MON NEWD ACROSS ERN OK AND ERN KS. FARTHER S...OTHER
SVR STORMS/STORM CLUSTERS MAY CONTINUE TO EVOLVE OVER N
CNTRL...CNTRL...AND S CNTRL TX AS AFOREMENTIONED SRN STREAM
DISTURBANCES INTERACT WITH STRONG/MOISTURE RICH SLY FLOW.

...ERN KS TO UPR MS VLY/GRT LKS...
STORMS NOW FORMING N OF WARM FRONT WILL CONTINUE TO POSE A THREAT
FOR SVR HAIL. 50-60 KT SSWLY LLJ WILL BE MAINTAINED AND SHIFT NNE
TO THE UPR MS VLY AS LEAD SHORT WAVE IMPULSE EJECTS NEWD. GIVEN
STRENGTH OF THE LLJ...A RELATIVELY NARROW CORRIDOR OF RICH
MOISTURE SHOULD MOVE RAPIDLY NNE...WITH SFC DEWPOINTS IN THE LOWER
60S REACHING SERN MN/CNTRL WI BY MID-LATE AFTN. EXTENT OF
DESTABILIZATION ALONG THIS AXIS REMAINS UNCERTAIN DUE TO CLOUDS AND
LIKELIHOOD FOR ADDITIONAL ELEVATED CONVECTION. NEVERTHELESS...SOME
BOUNDARY LAYER WARMING WILL OCCUR IN WAKE OF MORNING RAIN...WITH
MLCAPE OF 500-1000 J/KG POSSIBLE. STORMS SHOULD INTENSIFY ALONG AND
POSSIBLY AHEAD OF FRONT FROM KS NEWD THROUGH IA AS BOUNDARY RETURNS
SEWD IN WAKE OF SFC WAVE.

STRONG WIND PROFILES WITH EJECTING IMPULSE AND ATTENDANT LLJ WILL
RESULT IN LARGE HODOGRAPHS /0-1 KM SRH 200-300 M2 PER S2/...WITH
SUFFICIENT DEEP SHEAR FOR ORGANIZED STORMS...LIKELY BROKEN LINES
WITH EMBEDDED BOWING SEGMENTS AND SUPERCELLS. THESE WILL POSE A
THREAT FOR DMGG WIND AND ISOLD TORNADOES/HAIL. THIS ACTIVITY MAY
MERGE WITH OTHER CLUSTERS MOVING/DEVELOPING NEWD ACROSS ERN KS AND
NW MO EARLY MON.

INSTABILITY WILL DECREASE GRADUALLY WITH NEWD EXTENT INTO NRN WI/UPR
MI...ISOLD SVR WIND GUSTS MAY OCCUR CLOSE TO STRONG LLJ EARLY MON.

...PARTS OF UPSTATE NY/NE PA/WRN MA AND CT...
SFC DEWPOINTS IN THE MID-UPPER 60S WILL SPREAD E ACROSS THE
PRE-FRONTAL WARM SECTOR OVER SRN NY INTO SRN NEW ENGLAND. MODEST
MID LVL LAPSE RATES AROUND 6.5 C/KM ARE EXPECTED TO LIMIT DEGREE OF
DESTABILIZATION. HOWEVER...POTENTIAL WILL EXIST FOR A FEW TSTMS
THIS AFTN/EARLY EVE...WITH ACTIVITY SPREADING E GIVEN 30-40 WLY MID
LVL FLOW. STEEP LOW LEVEL LAPSE RATES/WELL MIXED BOUNDARY LAYER
SUGGESTS POSSIBILITY FOR A FEW STRONGER WIND GUSTS.

..CORFIDI/HART/SMITH/MEAD.. 04/26/2009

[janetjanet998]

going to be a long day

ULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE WICHITA KS
821 AM CDT SUN APR 26 2009

THE NATIONAL WEATHER SERVICE IN WICHITA HAS ISSUED A

* TORNADO WARNING FOR...
LINCOLN COUNTY IN CENTRAL KANSAS.

* UNTIL 900 AM CDT.

* AT 821 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS
DANGEROUS STORM WAS LOCATED NEAR LINCOLN...MOVING NORTHEAST AT 30
MPH.

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 188
NWS STORM PREDICTION CENTER NORMAN OK
600 AM CDT SUN APR 26 2009

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

SOUTHWEST AND CENTRAL KANSAS

EFFECTIVE THIS SUNDAY MORNING AND AFTERNOON FROM 600 AM UNTIL 100
PM CDT.

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

DISCUSSION...TSTMS EXPECTED TO INCREASE ALONG SW-NE WARM FRONT
REDEVELOPING NWD INTO CNTRL KS THIS MORNING...WHERE STRONG/MOIST SLY
LLJ WILL PERSIST BENEATH INCREASING LARGE SCALE FORCING FOR ASCENT.
WHILE LOW LVL UPLIFT ALONG BOUNDARY LIKELY WILL BE NECESSARY TO
INITIATE CONVECTION...WIND PROFILES AND BOUNDARY ORIENTATION SUGGEST
THAT STORMS WILL BE ABLE TO MOVE OFF THE FRONT AND INTERACT WITH
STRONG LOW LVL VEERING WIND PROFILES. THIS COULD SUPPORT A THREAT
FOR TORNADOES IN ADDITION TO VERY LARGE HAIL/HIGH WIND.

[oldlogin]

Just an FYI -The HRRR now includes the central Conus----

http://rapidrefresh.....gov/hrrrlarge/

[snowstormcanuck]

Don't usually post during the warm weather season since severe weather occurs so seldomly over in these parts. However, I think it's noteworthy to mention that during yesterday afternoon's squall line Pearson Int'l Airport reported a wind gust to 71 mph, which was the highest recorded gust at that location since January of 1978 (which I guess occurred with the Blizzard of '78).

About 16,000 households in the city of Toronto (including me for over 6 hours) lost power last evening.

[Pilot_Guy]

Sitting at the Motel 6 in Elk City, OK at this hour, mid to upper level overcast with some darkening to the west, although that has not seemed to limit the destabilization. It is already winder then yesterday.

- David Reimer
www.texasstormchasers.com

[Moneyman]

I have no idea why the SPC moved the Severe Weather risk to the North. It goes all the way to Green Bay. I highly doubt we see anything here but who knows.

Stay safe to everyone in Kansas, and Oklahoma areas.

[Aleking]

Moneyman, on Apr 26 2009, 09:48 AM, said:

I have no idea why the SPC moved the Severe Weather risk to the North. It goes all the way to Green Bay. I highly doubt we see anything here but who knows.

Stay safe to everyone in Kansas, and Oklahoma areas.

it's only a slight risk, but he front is retreating north pretty quick now.


Storms rolling through here and still very cold, hard to believe were getting anywhere near 80 today, i think this will be a fun day for those north and west.

some serious rumblers going on now.

[janetjanet998]

MESOSCALE DISCUSSION 0578
NWS STORM PREDICTION CENTER NORMAN OK
1019 AM CDT SUN APR 26 2009

AREAS AFFECTED...CNTRL KS SWD INTO NWRN OK AND ERN TX PNHDL

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 261519Z - 261615Z

TORNADO WATCH 188 WILL BE REORIENTED AND EXPANDED SW INTO NW OK AND
ERN TX PNHDL SOON.

APPARENT GRAVITY WAVE HAS INDUCED A LIKELY ELEVATED BAND OF TSTMS
FROM WEST OF KTOP SWWD TO NEAR KICT RECENTLY. ANOTHER BAND OF TSTMS
CONTINUES TO GROW ALONG PRIMARY CDFNT FARTHER TO THE W FROM EAST OF
KRSL TO NW OF KGAG.

TSTMS ARE LIKELY TO BUILD SWWD FROM THE TWO AFOREMENTIONED BANDS
THROUGH THE NEXT SEVERAL HOURS AS THE NM MID-LVL WAVE EJECTS NEWD.
BINOVC ACROSS MUCH OF THE REGION WILL ALLOW AIR MASS TO CONTINUE
WARMING IN THIS REGION...WITH WEAKEST CINH OVER KS EARLY. CAP
SHOULD WEAKEN GRADUALLY FARTHER SW WITH TIME...LEADING TO MORE
SFC-BASED ACTIVITY TO EVOLVE.

VWP/PROFILER DATA SHOW EVIDENCE OF EARLIER WAVE PASSAGE WITH A
VEERING-BACKING PATTERN IN THE LOWEST 6KM. THIS WILL COMPLICATE
STORM MODE EARLY...WITH LINEAR SEGMENTS MOST FAVORED.
HOWEVER...STORM ORGANIZATION INTO SUPERCELLS WITH VERY LARGE HAIL
WILL BECOME MORE LIKELY WITH TIME...ALONG WITH THE THREAT FOR
TORNADOES...ESP LATER THIS AFTN.

[The Green Menace]

HIGH RISK UPGRADE WILL INCLUDE SCNTRL KS AND NWRN/NCNTRL-WCNTRL OK
WITH A MDT RISK SPANNING FROM NWRN TX/ERN TX PNHDL ENEWD INTO CNTRL
OK AND CNTRL/ERN KS.

IMPRESSIVE INGREDIENTS COMING TOGETHER LATER THIS AFTN FOR A HIGH
POTENTIAL FOR WAVES OF LONG-LIVED SUPERCELLS WITH STRONG
TORNADOES...DESTRUCTIVE HAIL AND DAMAGING WIND GUSTS.

BRIEF THOUGHTS /DETAILS FORTHCOMING IN SWODY1 UPDATE/...

MORNING ACTIVITY DEVELOPING OUT OF ACCAS FIELD WILL TRANSLATE NWD
INTO CNTRL/ERN KS AND NWRN OK THROUGH EARLY AFTN. PORTIONS OF THIS
ACTIVITY COULD BECOME SFC-BASED AS POCKETS OF HEATING LOCALLY ERODE
CINH. ANOTHER WAVE OF STORMS IS LIKELY TO FORM UPSTREAM ALONG THE
DRYLINE/FRONT IN ERN TX PNHDL/NWRN TX LATER THIS AFTN AND
EVE...TRANSLATING ENE ACROSS THE MDT/HIGH RISK AREAS.

PLENTIFUL BOUNDARY LAYER MOISTURE ALREADY IN PLACE BELOW VERY STEEP
LAPSE RATES WILL CONTRIBUTE TO VERY UNSTABLE CONDITIONS...MLCAPES
3000-4000 J/KG. BULK SHEAR OF 45-50 KTS ORIENTED NORMAL TO THE
INITIATING BOUNDARIES AND PERSISTENT RICH MOISTURE INFLUX WILL FAVOR
LONG-LIVED DISCRETE SUPERCELLS. LOW-LEVEL FLOW WILL REMAIN BACKED
IN A CORRIDOR FROM NWRN TX INTO SCNTRL KS...IMMEDIATELY DOWNSTREAM
FROM AN INTENSIFYING SFC LOW OVER OK PNHDL/SWRN KS...BOOSTING SRH
AND RESULTING IN POTENTIAL FOR STRONG TORNADOES.

[bunkybeezer]

Will see a High Risk issued in 30mins.

[Aleking]

rock and roll, good luck to anyone chasing and stay safe.

[IndianaWeatherOnline]

SB Cape already over 3000 across much of Western Oklahoma, going to be a very very active day

[snowflake22]

Satellite data reveals the presence of a stable layer over Oklahoma and adjacent portions of southern Kansas. Note that gravity waves have been developing and increasing over western Oklahoma, including the vicinity of the dryline. The stable layer is likely mitigating the sustained development of additional convection in northwestern Oklahoma and southern Kansas, both of which have been affected by the passage of weak waves. In fact, there have been few Tornado Warnings within the Kansas Tornado Watch box over the past several hours, and the watch will expire within the next 1 1/2 hours. Ultimately, I believe that convective initiation will be delayed until the early/mid afternoon.

Western Oklahoma is becoming primed for a significant severe weather event. As 500 mb height contours decrease (ahead of the next upper level impulse), the main surface low will consolidate over eastern New Mexico and the Texas Panhandle. This trend is evident on recent surface maps. The backing low level winds will maintain significant 0-3 km helicities of 300+ m2/s2 over the region. This trend will be exacerbated when the 850 mb low level jet intensifies during the evening. Since early junk convection will not present issues, further destabilization will occur across western/central Oklahoma. Additionally, models have trended toward stronger upper level winds during the late afternoon and evening. Furthermore, the 12Z NAM has trended toward the RUC, depicting significant Tds of 65-70 F as far north as southwestern Missouri. Although the RUC is too aggressive, it is troubling when the NAM gravitates slightly toward the RUC's solution. The next GFS run will likely adhere to the trends.

Based on model trends, I strongly believe that a Day 1 High Risk is indispensable and necessary for a portion of western Oklahoma. The MDT Risk may require slight expansions to the NE and E, as well.

[IndianaWeatherOnline]

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 190
NWS STORM PREDICTION CENTER NORMAN OK
1110 AM CDT SUN APR 26 2009

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

A LARGE PART OF CENTRAL AND NORTHEAST KANSAS
PARTS OF WESTERN AND NORTHERN OKLAHOMA
PARTS OF EASTERN TEXAS PANHANDLE

EFFECTIVE THIS SUNDAY MORNING AND EVENING FROM 1110 AM UNTIL 700
PM CDT.

..THIS IS A PARTICULARLY DANGEROUS SITUATION

DESTRUCTIVE TORNADOES...LARGE HAIL TO 4 INCHES IN DIAMETER...
THUNDERSTORM WIND GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE
POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 85 STATUTE
MILES EAST AND WEST OF A LINE FROM 50 MILES WEST OF CLINTON
OKLAHOMA TO 65 MILES WEST NORTHWEST OF SAINT JOSEPH MISSOURI.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU0).

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 188...WW 189...

DISCUSSION...STRONG DEEP LAYER SHEAR COUPLED WITH A VERY UNSTABLE
AIR MASS WILL RESULT IN SUPERCELLS DEVELOPING ALONG AND E OF FRONTAL
ZONE THAT EXTENDS FROM NCENTRAL KS TO TX PANHANDLE. STORMS WILL
INCREASE RAPIDLY IN NUMBER AND INTENSITY THRU THE AFTERNOON AS WARM
SECTOR CONTINUES TO DESTABILIZE WITH TORNADIC SUPERCELLS BECOMING
MOST LIKELY DURING LATER PORTIONS OF WATCH PERIOD. POTENTIAL FOR
LONG LIVED TORNADIC SUPERCELLS ACCOMPANIED BY VERY LARGE HAIL.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 4 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 24035.

...HALES

[IndianaWeatherOnline]

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE AMARILLO TX
1114 AM CDT SUN APR 26 2009

THE NATIONAL WEATHER SERVICE IN AMARILLO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
NORTHWESTERN COLLINGSWORTH COUNTY IN THE PANHANDLE OF TEXAS
SOUTHERN WHEELER COUNTY IN THE PANHANDLE OF TEXAS

* UNTIL 1215 PM CDT

[snowflake22]

95/60 TOR probabilities are associated with the PDS!

[gkrangers]

snowflake22, on Apr 26 2009, 12:16 PM, said:

95/60 TOR probabilities are associated with the PDS!

Has there even been higher probs than >95/60?

[Indystorm]

With storms initiating off the dry line east of Amarillo this early we are in for a long and dangerous day indeed.

[msp]

Jeez, shaping up to be a big day

may head down to seMN or nIA to play the WF, but no decisions yet

we need this junk to clear out first