Severe Potential (05.04 & 05.05) - Day 1/2 MDT risk
Posted: Fri May 04, 2007 9:45 am
Day 1 1300Z Convective Outlook:
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0744 AM CDT FRI MAY 04 2007
VALID 041300Z - 051200Z
...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER
PARTS OF EASTERN CO...WESTERN AND CENTRAL KS...NORTHWEST OK...AND
SOUTHWEST NEB...
...THERE IS A SLGT RISK OF SVR TSTMS FROM SOUTHWEST TX INTO SD...
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF LA AND MS...
...CENTRAL PLAINS...
MORNING WATER VAPOR IMAGERY SHOWS BROAD UPPER TROUGH CONTINUING TO
ROTATE INTO THE PACIFIC NORTHWEST AND NORTHERN ROCKIES. STRONG
UPPER JET MAX NOW DIGGING SOUTHEASTWARD INTO THE FOUR CORNERS REGION
WILL NOSE INTO THE CENTRAL HIGH PLAINS BY THIS EVENING.
MEANWHILE...RAPID SURFACE CYCLOGENESIS IS EXPECTED OVER SOUTHEAST
CO. THIS WILL RESULT IN STRENGTHENING SOUTHERLY LOW LEVEL WINDS
THROUGHOUT THE PLAINS STATES. RECENT SURFACE ANALYSIS SHOWS
ABUNDANT LOW LEVEL MOISTURE OVER CENTRAL TX AND SOUTHERN OK...WHICH
WILL SPREAD/MIX QUICKLY NORTHWARD INTO KS TODAY. STRONG SURFACE
HEATING IS LIKELY THROUGHOUT THIS REGION TODAY AFTER MORNING LOW
CLOUDS BURN OFF...RESULTING IN AN EXTREMELY UNSTABLE AIR MASS ALONG
AND EAST OF THE DRYLINE FROM SOUTHWEST KS INTO WESTERN OK. EASTERLY
LOW LEVEL WINDS WILL ALSO ADVECT 50S DEWPOINTS WESTWARD ACROSS MOST
OF EASTERN CO BY MID AFTERNOON.
PRESENT INDICATIONS ARE THAT FIRST CONVECTION WILL BE ALONG THE
FOOTHILLS OF SOUTH-CENTRAL CO NEAR PUB. THESE STORMS WILL BE AIDED
BY EAST-NORTHEAST SURFACE WINDS AND UPSLOPE FLOW. VERTICAL SHEAR
PROFILES IN THIS AREA SUGGEST STORMS WILL RAPIDLY BECOME
SUPERCELLULAR WITH A RISK OF VERY LARGE HAIL AND A FEW TORNADOES.
ACTIVITY WILL LIKELY INCREASE IN COVERAGE DURING THE EARLY EVENING
AS STORMS SPREAD NORTHEASTWARD TOWARD NORTHWEST KS AND SOUTHWEST
NEB. TORNADO THREAT SHOULD INCREASE WITH EASTWARD EXTENT AS STORMS
MOVE INTO MORE MOIST BOUNDARY LAYER.
FARTHER SOUTH...SURFACE DRYLINE IS EXPECTED TO EXTEND FROM SOUTHWEST
KS NEAR DDC SOUTHWARD ALONG THE OK/TX BORDER. SHORTWAVE RIDGING IS
OCCURRING OVER THIS REGION THIS MORNING...RESULTING IN A
STRENGTHENING CAP AND LITTLE IN THE WAY OF CONVECTIVE THREAT UNTIL
THIS AFTERNOON. MODELS VARY ON WHETHER THE CAP CAN WEAKEN
SUFFICIENTLY DOWN THE DRYLINE FOR INITIATION THIS EVENING. HIGHEST
CONFIDENCE IS FOR STORMS TO FORM NEAR WARM FRONT-DRYLINE TRIPLE
POINT NEAR DDC AND TRACK EASTWARD DURING THE EVENING. FORECAST
SOUNDINGS IN THIS AREA SHOW EXTREME INSTABILITY AND MORE THAN
SUFFICIENT VERTICAL SHEAR PROFILES FOR SUPERCELLS CAPABLE OF VERY
LARGE HAIL...DAMAGING WINDS...AND STRONG TORNADOES. RIGHT NOW IT
APPEARS THAT DEVELOPMENT DOWN THE DRYLINE INTO OK WILL BE MUCH MORE
ISOLATED WITH A VERY CONDITIONAL SEVERE THREAT. ANY STORMS THAT CAN
FORM IN THIS AREA WILL POSE A RISK OF SIGNIFICANT SEVERE. PARTS OF
OK AND NORTHWEST TX MAY SEE CONTINUED THREAT AFTER MIDNIGHT AS LARGE
SCALE FORCING BEGINS TO OVERSPREAD THE SOUTHERN PLAINS...LEADING TO
SCATTERED THUNDERSTORM DEVELOPMENT CAPABLE OF LARGE HAIL.
...LOWER MS VALLEY...
SCATTERED STRONG THUNDERSTORMS ARE ONGOING THIS MORNING OVER PARTS
OF LA AND SOUTHERN MS. THESE STORMS ARE LIKELY TO CONTINUE
THROUGHOUT THE DAY WITH A RISK OF LOCALLY DAMAGING WINDS AND HAIL.
WILL MAINTAIN ONLY LOW SEVERE PROBABILITIES FARTHER NORTH DUE TO
UNCERTAINTIES WITH AIR MASS RECOVERY AND INSTABILITY. REFER OF MCD
NUMBER 680 FOR FURTHER DETAILS ON THIS AREA.
..HART/TAYLOR.. 05/04/2007
=================================================================================
Day 2 0800Z Convective Outlook
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0130 AM CDT FRI MAY 04 2007
VALID 051200Z - 061200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF CNTRL AND ERN
NEB...CNTRL KS...NW OK AND CNTRL OK...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE GREAT
PLAINS AND LOWER OH VALLEY...
...SEVERE WEATHER OUTBREAK WITH TORNADOES POSSIBLE SATURDAY AND
SATURDAY NIGHT ACROSS PARTS OF THE GREAT PLAINS...
...GREAT PLAINS REGION...
A POTENT UPPER-LEVEL TROUGH OVER THE WRN U.S. IS FORECAST TO MOVE
SLOWLY EWD INTO THE ROCKIES AS AN IMPRESSIVE 100 KT MID-LEVEL JET
EJECTS OUT OF THE BASE OF THE TROUGH NEWD ACROSS THE PLAINS SATURDAY
AND SATURDAY NIGHT. MODEL FORECASTS HAVE BEEN INCREASINGLY
AGGRESSIVE RUN TO RUN CONCERNING THE TIMING OF THE UPPER-LEVEL
TROUGH AND IT APPEARS THAT THE BRUNT OF LARGE-SCALE ASCENT WITH THE
UPPER-LEVEL TROUGH WILL COME EWD INTO THE PLAINS ON DAY 2. THIS
SHOULD RESULT IN STORM DEVELOPMENT BECOMING WIDESPREAD FROM THE NRN
AND CNTRL PLAINS EXTENDING SWD INTO PARTS OF THE SRN PLAINS. IN
ADDITION...A BROAD 50 KT LOW-LEVEL JET WILL BE IN PLACE ACROSS THE
PLAINS WITH A QUALITY WARM SECTOR WHICH WILL LIKELY RESULT IN A
THREAT FOR SUPERCELLS OVER A LARGE AREA SATURDAY AFTERNOON AND
EVENING. LOW-LEVEL SHEAR PROFILES ALSO APPEAR FAVORABLE FOR
TORNADOES ACROSS THE PLAINS REGION ON DAY 2.
THE MAIN UNCERTAINTY CONCERNING DAY 2 WILL BE HOW CONVECTION ON
FRIDAY NIGHT AND SATURDAY MORNING WILL AFFECT PORTIONS OF THE WARM
SECTOR. THE CURRENT THINKING IS THAT STORM COVERAGE WILL BE GREATEST
LATE FRIDAY NIGHT FROM A WARM FRONT IN SCNTRL NEB EXTENDING NWD INTO
SRN SD. STORMS FURTHER SOUTH ALONG THE DRYLINE SHOULD BECOME
ISOLATED ENOUGH BY SATURDAY MORNING THAT EFFECTS REDUCING
DESTABILIZATION ON SATURDAY SHOULD BE MINIMAL.
CONCERNING THE THREAT FOR SIGNIFICANT SEVERE...FORECAST SOUNDINGS
EAST OF A DRYLINE ACROSS SCNTRL NEB...CNTRL KS...WRN OK AND
NORTHWEST TX SHOW IMPRESSIVE LOW-LEVEL SHEAR PROFILES WITH SFC
DEWPOINTS RANGING FROM 65 TO 70 F. THIS COMBINED WITH THE AMOUNT OF
INSTABILITY AND FORCING SUGGEST SOME SIGNIFICANT TORNADOES MAY OCCUR
EAST OF THE DRYLINE ACROSS THE MODERATE RISK AREA. A CONCENTRATED
THREAT AREA FOR SIGNIFICANT TORNADOES MAY ALSO EXIST WITH SUPERCELLS
THAT TRACK EWD ALONG THE WARM FRONT ACROSS PARTS OF SRN AND CNTRL
NEB. CONCERNING LARGE HAIL...AN ELEVATED MIXED LAYER ASSOCIATED WITH
THE MID-LEVEL JET SHOULD SPREAD EWD INTO THE PLAINS SATURDAY. STEEP
MID-LEVEL LAPSE RATES ASSOCIATED WITH THIS LAYER COMBINED WITH THE
AMOUNT OF INSTABILITY AND VERTICAL SHEAR SHOULD BE SUFFICIENT FOR
VERY LARGE HAIL WITH THE STRONGER SUPERCELLS.
SEVERE WEATHER COVERAGE SHOULD BE LESS ACROSS THE NRN PLAINS WHERE
INSTABILITY WILL NOT BE AS GREAT. ALSO...A DECREASE IN SEVERE
WEATHER COVERAGE SHOULD EXIST ACROSS WCNTRL TX WHERE VERTICAL SHEAR
WILL BE WEAKER DUE TO LESS OF AN INFLUENCE FROM THE MID-LEVEL JET.
THE STRONG INSTABILITY ACROSS PARTS OF THE PLAINS AND AMOUNT OF
LARGE-SCALE FORCING WITH THE UPPER-LEVEL TROUGH SHOULD SUSTAIN
SEVERAL MCS CLUSTERS OVERNIGHT WITH A SEVERE THREAT LIKELY
CONTINUING ACROSS PARTS OF THE PLAINS THROUGH LATE IN THE PERIOD.
...LOWER OH VALLEY...
AT THE SFC...A STATIONARY FRONT WILL LIKELY EXTEND SEWD FROM THE
CNTRL PLAINS INTO MO AND THE MID MS VALLEY SATURDAY. ALTHOUGH AN
UPPER-LEVEL RIDGE IS FORECAST ACROSS THIS REGION SATURDAY...FORECAST
SOUNDINGS SHOW STRONGLY VEERING WIND PROFILES AT THE LOW TO
MID-LEVELS MAINLY FROM THE STATIONARY FRONT NEWD. IN
ADDITION...POCKETS OF MODERATE INSTABILITY SHOULD DEVELOP ON THE
COOL SIDE OF THE BOUNDARY WHICH IS SUPPORTED BY THE NAM...GFS AND
NAMKF SOLUTIONS. THIS SHOULD BE SUFFICIENT FOR A FEW SEVERE STORM
CLUSTERS IN THE LATE AFTERNOON AND EARLY EVENING.
HOWEVER...LARGE-SCALE ASCENT SHOULD REMAIN WEAK AND STORM COVERAGE
SHOULD REMAIN ISOLATED TO SCATTERED ACROSS THE REGION WITH THE
GREATEST THREAT LIKELY CONCENTRATED AROUND PEAK HEATING.
..BROYLES.. 05/04/2007
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0744 AM CDT FRI MAY 04 2007
VALID 041300Z - 051200Z
...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER
PARTS OF EASTERN CO...WESTERN AND CENTRAL KS...NORTHWEST OK...AND
SOUTHWEST NEB...
...THERE IS A SLGT RISK OF SVR TSTMS FROM SOUTHWEST TX INTO SD...
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF LA AND MS...
...CENTRAL PLAINS...
MORNING WATER VAPOR IMAGERY SHOWS BROAD UPPER TROUGH CONTINUING TO
ROTATE INTO THE PACIFIC NORTHWEST AND NORTHERN ROCKIES. STRONG
UPPER JET MAX NOW DIGGING SOUTHEASTWARD INTO THE FOUR CORNERS REGION
WILL NOSE INTO THE CENTRAL HIGH PLAINS BY THIS EVENING.
MEANWHILE...RAPID SURFACE CYCLOGENESIS IS EXPECTED OVER SOUTHEAST
CO. THIS WILL RESULT IN STRENGTHENING SOUTHERLY LOW LEVEL WINDS
THROUGHOUT THE PLAINS STATES. RECENT SURFACE ANALYSIS SHOWS
ABUNDANT LOW LEVEL MOISTURE OVER CENTRAL TX AND SOUTHERN OK...WHICH
WILL SPREAD/MIX QUICKLY NORTHWARD INTO KS TODAY. STRONG SURFACE
HEATING IS LIKELY THROUGHOUT THIS REGION TODAY AFTER MORNING LOW
CLOUDS BURN OFF...RESULTING IN AN EXTREMELY UNSTABLE AIR MASS ALONG
AND EAST OF THE DRYLINE FROM SOUTHWEST KS INTO WESTERN OK. EASTERLY
LOW LEVEL WINDS WILL ALSO ADVECT 50S DEWPOINTS WESTWARD ACROSS MOST
OF EASTERN CO BY MID AFTERNOON.
PRESENT INDICATIONS ARE THAT FIRST CONVECTION WILL BE ALONG THE
FOOTHILLS OF SOUTH-CENTRAL CO NEAR PUB. THESE STORMS WILL BE AIDED
BY EAST-NORTHEAST SURFACE WINDS AND UPSLOPE FLOW. VERTICAL SHEAR
PROFILES IN THIS AREA SUGGEST STORMS WILL RAPIDLY BECOME
SUPERCELLULAR WITH A RISK OF VERY LARGE HAIL AND A FEW TORNADOES.
ACTIVITY WILL LIKELY INCREASE IN COVERAGE DURING THE EARLY EVENING
AS STORMS SPREAD NORTHEASTWARD TOWARD NORTHWEST KS AND SOUTHWEST
NEB. TORNADO THREAT SHOULD INCREASE WITH EASTWARD EXTENT AS STORMS
MOVE INTO MORE MOIST BOUNDARY LAYER.
FARTHER SOUTH...SURFACE DRYLINE IS EXPECTED TO EXTEND FROM SOUTHWEST
KS NEAR DDC SOUTHWARD ALONG THE OK/TX BORDER. SHORTWAVE RIDGING IS
OCCURRING OVER THIS REGION THIS MORNING...RESULTING IN A
STRENGTHENING CAP AND LITTLE IN THE WAY OF CONVECTIVE THREAT UNTIL
THIS AFTERNOON. MODELS VARY ON WHETHER THE CAP CAN WEAKEN
SUFFICIENTLY DOWN THE DRYLINE FOR INITIATION THIS EVENING. HIGHEST
CONFIDENCE IS FOR STORMS TO FORM NEAR WARM FRONT-DRYLINE TRIPLE
POINT NEAR DDC AND TRACK EASTWARD DURING THE EVENING. FORECAST
SOUNDINGS IN THIS AREA SHOW EXTREME INSTABILITY AND MORE THAN
SUFFICIENT VERTICAL SHEAR PROFILES FOR SUPERCELLS CAPABLE OF VERY
LARGE HAIL...DAMAGING WINDS...AND STRONG TORNADOES. RIGHT NOW IT
APPEARS THAT DEVELOPMENT DOWN THE DRYLINE INTO OK WILL BE MUCH MORE
ISOLATED WITH A VERY CONDITIONAL SEVERE THREAT. ANY STORMS THAT CAN
FORM IN THIS AREA WILL POSE A RISK OF SIGNIFICANT SEVERE. PARTS OF
OK AND NORTHWEST TX MAY SEE CONTINUED THREAT AFTER MIDNIGHT AS LARGE
SCALE FORCING BEGINS TO OVERSPREAD THE SOUTHERN PLAINS...LEADING TO
SCATTERED THUNDERSTORM DEVELOPMENT CAPABLE OF LARGE HAIL.
...LOWER MS VALLEY...
SCATTERED STRONG THUNDERSTORMS ARE ONGOING THIS MORNING OVER PARTS
OF LA AND SOUTHERN MS. THESE STORMS ARE LIKELY TO CONTINUE
THROUGHOUT THE DAY WITH A RISK OF LOCALLY DAMAGING WINDS AND HAIL.
WILL MAINTAIN ONLY LOW SEVERE PROBABILITIES FARTHER NORTH DUE TO
UNCERTAINTIES WITH AIR MASS RECOVERY AND INSTABILITY. REFER OF MCD
NUMBER 680 FOR FURTHER DETAILS ON THIS AREA.
..HART/TAYLOR.. 05/04/2007
=================================================================================
Day 2 0800Z Convective Outlook
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0130 AM CDT FRI MAY 04 2007
VALID 051200Z - 061200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF CNTRL AND ERN
NEB...CNTRL KS...NW OK AND CNTRL OK...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE GREAT
PLAINS AND LOWER OH VALLEY...
...SEVERE WEATHER OUTBREAK WITH TORNADOES POSSIBLE SATURDAY AND
SATURDAY NIGHT ACROSS PARTS OF THE GREAT PLAINS...
...GREAT PLAINS REGION...
A POTENT UPPER-LEVEL TROUGH OVER THE WRN U.S. IS FORECAST TO MOVE
SLOWLY EWD INTO THE ROCKIES AS AN IMPRESSIVE 100 KT MID-LEVEL JET
EJECTS OUT OF THE BASE OF THE TROUGH NEWD ACROSS THE PLAINS SATURDAY
AND SATURDAY NIGHT. MODEL FORECASTS HAVE BEEN INCREASINGLY
AGGRESSIVE RUN TO RUN CONCERNING THE TIMING OF THE UPPER-LEVEL
TROUGH AND IT APPEARS THAT THE BRUNT OF LARGE-SCALE ASCENT WITH THE
UPPER-LEVEL TROUGH WILL COME EWD INTO THE PLAINS ON DAY 2. THIS
SHOULD RESULT IN STORM DEVELOPMENT BECOMING WIDESPREAD FROM THE NRN
AND CNTRL PLAINS EXTENDING SWD INTO PARTS OF THE SRN PLAINS. IN
ADDITION...A BROAD 50 KT LOW-LEVEL JET WILL BE IN PLACE ACROSS THE
PLAINS WITH A QUALITY WARM SECTOR WHICH WILL LIKELY RESULT IN A
THREAT FOR SUPERCELLS OVER A LARGE AREA SATURDAY AFTERNOON AND
EVENING. LOW-LEVEL SHEAR PROFILES ALSO APPEAR FAVORABLE FOR
TORNADOES ACROSS THE PLAINS REGION ON DAY 2.
THE MAIN UNCERTAINTY CONCERNING DAY 2 WILL BE HOW CONVECTION ON
FRIDAY NIGHT AND SATURDAY MORNING WILL AFFECT PORTIONS OF THE WARM
SECTOR. THE CURRENT THINKING IS THAT STORM COVERAGE WILL BE GREATEST
LATE FRIDAY NIGHT FROM A WARM FRONT IN SCNTRL NEB EXTENDING NWD INTO
SRN SD. STORMS FURTHER SOUTH ALONG THE DRYLINE SHOULD BECOME
ISOLATED ENOUGH BY SATURDAY MORNING THAT EFFECTS REDUCING
DESTABILIZATION ON SATURDAY SHOULD BE MINIMAL.
CONCERNING THE THREAT FOR SIGNIFICANT SEVERE...FORECAST SOUNDINGS
EAST OF A DRYLINE ACROSS SCNTRL NEB...CNTRL KS...WRN OK AND
NORTHWEST TX SHOW IMPRESSIVE LOW-LEVEL SHEAR PROFILES WITH SFC
DEWPOINTS RANGING FROM 65 TO 70 F. THIS COMBINED WITH THE AMOUNT OF
INSTABILITY AND FORCING SUGGEST SOME SIGNIFICANT TORNADOES MAY OCCUR
EAST OF THE DRYLINE ACROSS THE MODERATE RISK AREA. A CONCENTRATED
THREAT AREA FOR SIGNIFICANT TORNADOES MAY ALSO EXIST WITH SUPERCELLS
THAT TRACK EWD ALONG THE WARM FRONT ACROSS PARTS OF SRN AND CNTRL
NEB. CONCERNING LARGE HAIL...AN ELEVATED MIXED LAYER ASSOCIATED WITH
THE MID-LEVEL JET SHOULD SPREAD EWD INTO THE PLAINS SATURDAY. STEEP
MID-LEVEL LAPSE RATES ASSOCIATED WITH THIS LAYER COMBINED WITH THE
AMOUNT OF INSTABILITY AND VERTICAL SHEAR SHOULD BE SUFFICIENT FOR
VERY LARGE HAIL WITH THE STRONGER SUPERCELLS.
SEVERE WEATHER COVERAGE SHOULD BE LESS ACROSS THE NRN PLAINS WHERE
INSTABILITY WILL NOT BE AS GREAT. ALSO...A DECREASE IN SEVERE
WEATHER COVERAGE SHOULD EXIST ACROSS WCNTRL TX WHERE VERTICAL SHEAR
WILL BE WEAKER DUE TO LESS OF AN INFLUENCE FROM THE MID-LEVEL JET.
THE STRONG INSTABILITY ACROSS PARTS OF THE PLAINS AND AMOUNT OF
LARGE-SCALE FORCING WITH THE UPPER-LEVEL TROUGH SHOULD SUSTAIN
SEVERAL MCS CLUSTERS OVERNIGHT WITH A SEVERE THREAT LIKELY
CONTINUING ACROSS PARTS OF THE PLAINS THROUGH LATE IN THE PERIOD.
...LOWER OH VALLEY...
AT THE SFC...A STATIONARY FRONT WILL LIKELY EXTEND SEWD FROM THE
CNTRL PLAINS INTO MO AND THE MID MS VALLEY SATURDAY. ALTHOUGH AN
UPPER-LEVEL RIDGE IS FORECAST ACROSS THIS REGION SATURDAY...FORECAST
SOUNDINGS SHOW STRONGLY VEERING WIND PROFILES AT THE LOW TO
MID-LEVELS MAINLY FROM THE STATIONARY FRONT NEWD. IN
ADDITION...POCKETS OF MODERATE INSTABILITY SHOULD DEVELOP ON THE
COOL SIDE OF THE BOUNDARY WHICH IS SUPPORTED BY THE NAM...GFS AND
NAMKF SOLUTIONS. THIS SHOULD BE SUFFICIENT FOR A FEW SEVERE STORM
CLUSTERS IN THE LATE AFTERNOON AND EARLY EVENING.
HOWEVER...LARGE-SCALE ASCENT SHOULD REMAIN WEAK AND STORM COVERAGE
SHOULD REMAIN ISOLATED TO SCATTERED ACROSS THE REGION WITH THE
GREATEST THREAT LIKELY CONCENTRATED AROUND PEAK HEATING.
..BROYLES.. 05/04/2007