SPC MD 1550

MD 1550 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR CENTRAL AND SOUTHERN IA

MD 1550 Image


MESOSCALE DISCUSSION 1550
NWS STORM PREDICTION CENTER NORMAN OK
1240 PM CDT MON JUL 27 2015

AREAS AFFECTED...CENTRAL AND SOUTHERN IA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 271740Z - 272045Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...A RELATIVELY COMPACT MCS WILL ADVANCE TO THE EAST ACROSS
CENTRAL AND PORTIONS OF SOUTHERN IA THIS AFTERNOON.  ALTHOUGH MOST
OF THE WIND GUSTS ASSOCIATED WITH THIS ACTIVITY SHOULD REMAIN
SUB-SEVERE...LOCALLY STRONG WIND GUSTS /POTENTIALLY REACHING OR
EXCEEDING 50 KT/ CANNOT BE RULED OUT.

DISCUSSION...DMX RADAR TRENDS AND PERSISTENT CLOUD-TOP COOLING PER
IR SATELLITE IMAGERY INDICATED A FORWARD-PROPAGATING LINEAR MCS
ADVANCING EASTWARD ACROSS CENTRAL IA.  AS THE STORMS MOVED THROUGH
THE COUNTIES OF BOONE...DALLAS...AND MADISON THE ATTENDANT OUTFLOW
BOUNDARY HAD MOVED AHEAD OF THE STRONGER BAND OF STORMS INDICATING
ANY STRONGER WIND GUSTS ATTENDANT TO THIS MCS MAY NOT BE REACHING
THE SURFACE.  HOWEVER...IF THE STRONGER ACTIVITY CAN OVERTAKE THE
OUTFLOW BOUNDARY...AS MAY BE ONGOING IN NORTHEAST DALLAS COUNTY AND
PORTIONS OF WESTERN POLK COUNTY...THEN 55+ KT WLY WINDS OBSERVED
AROUND 500 FEET AGL IN THAT PORTION OF DALLAS COUNTY WILL HAVE A
GREATER POTENTIAL TO REACH THE SURFACE.

GIVEN THE ORGANIZATION OF THIS MCS WITH AN ACCOMPANYING COLD POOL
AND REAR-INFLOW JET OF 40-45 KT AT 1-2 KM AGL PER DMX RADAR 
COMBINED WITH A SURFACE-BASED INFLOW REGIME THAT HAS MODERATELY
STRONG INSTABILITY...THIS COMPLEX IS EXPECTED TO PERSIST THROUGH THE
AFTERNOON...TRACKING TO EAST ALONG AN INSTABILITY GRADIENT.  AN
EVENTUAL SOUTHEASTWARD TURN MAY OCCUR BETWEEN 19-20Z AS THE SOUTHERN
FLANK REACHES POWESHIEK AND MAHASKA COUNTIES WHERE THE INSTABILITY
GRADIENT IS ORIENTED NW-SE.  ALTHOUGH SHORT-TERM MODELS HAVE HAD
DIFFICULTY FORECASTING THIS COMPLEX...THE HRRR /THOUGH SLOW WITH ITS
DEVELOPMENT AND PLACEMENT/ SUGGESTS THIS STORM COMPLEX SHOULD
PERSIST THROUGH THE AFTERNOON WITH AN EVENTUAL SEWD MOVEMENT.  ELY
SURFACE WINDS WILL CONTINUE TO ENHANCE DEEP SHEAR FOR STORM
ORGANIZATION...WHILE FORCING FOR ASCENT ATTENDANT TO A WEAK
EWD-MOVING MIDLEVEL IMPULSE AIDS IN SUSTAINING TSTM DEVELOPMENT
WITHIN THIS MCS.

..PETERS/GOSS.. 07/27/2015

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...DVN...DMX...

LAT...LON   41909250 41849204 41549168 40999158 40909197 40899242
            41129292 41339404 41629419 41869415 42029404 41909250 

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from SPC Mesoscale Discussions http://1.usa.gov/1U2v8tV

SPC Jul 26, 2015 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook

Day 1 Outlook Image

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0257 PM CDT SUN JUL 26 2015

VALID 262000Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTERNOON AND EVENING
ACROSS THE NORTHERN AND CENTRAL HIGH PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS SURROUNDING AREAS OF THE
PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE OHIO
VALLEY...ALLEGHENY PLATEAU INTO THE HUDSON VALLEY...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF SOUTHWEST
THROUGH CENTRAL MONTANA...

...SUMMARY...
A FEW SEVERE STORMS ARE POSSIBLE THIS AFTERNOON ACROSS PARTS OF THE
NORTHERN AND CENTRAL HIGH PLAINS.  WIDELY SCATTERED STRONG STORMS
ARE ALSO POSSIBLE ACROSS PARTS OF THE OHIO VALLEY...AND THE
ALLEGHENY PLATEAU REGION INTO THE HUDSON VALLEY...AS WELL AS ACROSS
PARTS OF SOUTHWESTERN INTO CENTRAL MONTANA.

...20Z OUTLOOK UPDATE...
CATEGORICAL AND PROBABILISTIC LINES HAVE BEEN ADJUSTED TO ACCOUNT
FOR THE LATEST TRENDS CONCERNING CONVECTIVE DEVELOPMENT AND
DESTABILIZATION.

...PLAINS...
WIDELY SCATTERED THUNDERSTORM DEVELOPMENT IS ALREADY UNDERWAY NEAR
THE LEE SURFACE TROUGH ACROSS THE CENTRAL AND NORTHERN HIGH
PLAINS...LIKELY TO DUE AT LEAST THE APPROACH OF CONVECTIVE
TEMPERATURES...WHERE LOW-LEVEL CONVERGENCE HAS BECOME LOCALLY
ENHANCED.  THIS ACTIVITY IS EXPECTED TO PERSIST AND GRADUALLY
INTENSIFY THROUGH LATE AFTERNOON IN AN ENVIRONMENT THAT APPEARS
CHARACTERIZED BY STEEP LOWER/MID TROPOSPHERIC LAPSE RATES...SIZABLE
CAPE AND WEAK TO MODEST SHEAR.  AN INCREASE IN STORM COVERAGE IS
ALSO PROBABLE...PARTICULARLY ACROSS PARTS OF EASTERN COLORADO AND
NORTHWEST KANSAS INTO WESTERN NEBRASKA...LIKELY AIDED BY FORCING
ASSOCIATED WITH A WEAK IMPULSE EMBEDDED WITHIN THE MID-LEVEL MOIST
PLUME WRAPPING AROUND THE WESTERN PERIPHERY OF THE SOUTHERN PLAINS
SUBTROPICAL HIGH CENTER.

...OHIO VALLEY INTO NORTHEAST...
LOW PROBABILITIES FOR MARGINALLY SEVERE HAIL AND WIND ARE BEING
MAINTAINED ALONG AN AXIS OF MODEST BOUNDARY LAYER DESTABILIZATION
WHICH HAS TAKEN PLACE WITH DAYTIME HEATING ACROSS PARTS OF THE OHIO
VALLEY...AND THE ALLEGHENY PLATEAU INTO THE HUDSON VALLEY.  IN THE
PRESENCE OF WEAK DEEP LAYER MEAN FLOW AND SHEAR...SUBSTANTIVE
FURTHER CONVECTIVE INTENSIFICATION DOES NOT SEEM TOO LIKELY...BUT
CONSIDERABLE THUNDERSTORM ACTIVITY IS ALREADY UNDERWAY.

...MIDDLE MISSISSIPPI VALLEY...
CONVECTIVE OUTFLOW HAS STABILIZED THE BOUNDARY LAYER NEAR THE
IMMEDIATE VICINITY OF THE MISSISSIPPI RIVER ACROSS MISSOURI/
ILLINOIS AND IOWA.  ON THE WESTERN FLANK OF A REMNANT OUTFLOW
BOUNDARY NOW ARCING ACROSS WESTERN TENNESSEE AND NORTHEAST ARKANSAS
INTO PARTS OF SOUTH CENTRAL MISSOURI...MOISTURE CONTENT REMAINS
SEASONABLY HIGH AND IS CONTRIBUTING TO LARGE MIXED LAYER CAPE. 
ALTHOUGH SOME RECENT INCREASE IN THUNDERSTORMS IS NOTED TO THE EAST
AND SOUTHEAST OF FORT LEONARD WOOD...THE TENDENCY FOR WARMING ALOFT
IN CONJUNCTION WITH GENERALLY WEAK FORCING FOR ASCENT...DEEP LAYER
MEAN FLOW AND SHEAR SEEM TO LIMIT CONVECTIVE POTENTIAL THROUGH THE
REMAINDER OF THE PERIOD.

...NORTHERN ROCKIES...
THE LACK OF MORE SUBSTANTIVE POST-FRONTAL BOUNDARY LAYER MOISTENING
AND DESTABILIZATION APPEARS THE MAIN LIMITING FACTOR AS
THUNDERSTORMS DEVELOP ACROSS THE MOUNTAINS OF SOUTHWEST INTO CENTRAL
MONTANA IN RESPONSE TO STRENGTHENING FORCING FOR ASCENT.  DEEP LAYER
SHEAR IS SUFFICIENT TO SUPPORT ORGANIZED SEVERE STORMS...INCLUDING
SUPERCELLS.  HOWEVER...AT THIS POINT...TOO MUCH UNCERTAINTY REMAINS
TO SUPPORT ANYTHING BEYOND MARGINAL SEVERE PROBABILITIES.

..KERR.. 07/26/2015

.PREV DISCUSSION... /ISSUED 1130 AM CDT SUN JUL 26 2015/

...CNTRL/NRN HIGH PLAINS...
MORNING SATELLITE IMAGERY DEPICTS MOSTLY CLEAR SKIES ACROSS THE HIGH
PLAINS FROM THE RIO GRANDE TO CANADIAN BORDER. DIURNAL
HEATING/MIXING AND WEAK BACKGROUND ASCENT/HEIGHT FALLS FROM ERN CO
NWD SHOULD CONTRIBUTE TO WIDELY SCATTERED CONVECTIVE INITIATION
ALONG/AHEAD OF HIGH PLAINS LEE/THERMAL TROUGH LATER THIS AFTERNOON.
DESPITE VERY WARM MID-LEVEL TEMPS DELINEATING LOWER LAYER OF EML
PLUME...DEEPER BOUNDARY LAYER MIXING/HEATING SHOULD BE ABLE TO AID
IN OVERCOMING CONVECTIVE INHIBITION WITH AT LEAST A FEW STORMS ABLE
TO TAP INTO STRONG SURFACE-BASED INSTABILITY. EFFECTIVE SHEAR ON THE
ORDER OF 25-30KT SHOULD SUPPORT A COUPLE OF MORE PERSISTENT STORM
UPDRAFTS/SUPERCELLS WITH THE CAPABILITY OF PRODUCING HAIL AND HIGH
WINDS. SOMEWHAT GREATER STORM COVERAGE AND PERSISTENCE MAY EXIST
ACROSS ERN CO WHERE STORMS MAY DRIFT TOWARD AXIS OF GREATER LOW
LEVEL MOISTURE/DESTABILIZATION ALONG THE CO/KS BORDER WITH TIME.
SOME OF THIS ACTIVITY MAY ALSO PERSIST INTO THE NIGHTTIME HOURS AS
MASS TRANSPORT AND LOW LEVEL ASCENT ARE MAXIMIZED ON THE NOSE OF
PLAINS LLJ.

...MIDWEST/TO NORTH OF OH VALLEY/ALLEGHENY PLATEAU...
FORECAST IS COMPLICATED ACROSS THE MIDWEST GIVEN THE DECAYING
REMNANTS OF A PAIR OF OVERNIGHT MCS/S...ONE NOW CROSSING THE LOWER
OH RIVER VALLEY IN WRN KY AND THE MO BOOTHEEL...THE OTHER MOVING
INTO WRN IL FROM SERN IA AND ERN MO. NRN SYSTEM APPEARS TO BE
ASSOCIATED WITH A RELATIVELY STRONG SHORTWAVE TROUGH EVIDENT ON
WATER VAPOR SATELLITE IMAGERY OVER MN/IA...AND A PACKET OF STRONGER
30-35 KT MIDLEVEL FLOW PER REGIONAL VWP OBSERVATIONS.

STRONG HEATING IN THE WAKE OF THE SHORTWAVE/MCV ACROSS MN/IA WILL
CONTRIBUTE TO AN AXIS OF STRONG INSTABILITY ALONG THE EDGE OF THE
PLAINS CAPPING INVERSION/EML. WHILE LARGE SCALE SUPPORT FOR ASCENT
WILL PROBABLY BE WANING ALONG THIS CORRIDOR...A CONDITIONAL SEVERE
HAIL/WIND RISK WILL BE MAINTAINED IN THE EVENT ISOLATED STORMS CAN
DEVELOP GIVEN CONTINUING LOW LEVEL CONVERGENCE ALONG RESIDUAL FRONT
AND OUTFLOW BOUNDARIES REMAINING IN THE PRESENCE OF STRONG TO
LOCALLY EXTREME DESTABILIZATION.

FARTHER EAST....FROM IND TO PA...INSTABILITY AND WEAK LIFT WILL BE
FOCUSED ALONG THE STALLED FRONT SITUATED ACROSS THESE AREAS. A FEW
AFTERNOON OR EARLY EVENING STORMS COULD RESULT IN LOCALLY STRONG
GUSTS AND PERHAPS A COUPLE OF TREE-DOWN EVENTS.

...NORTHEAST...
MODEST WARM SECTOR DESTABILIZATION WAS UNDERWAY WITH LATEST
OBJECTIVE DATA INDICATING MLCAPE OF AROUND 1000 J/KG ACROSS MUCH OF
NY AND LITTLE IN THE WAY OF INHIBITION. LARGE SCALE PATTERN ACROSS
NEW ENGLAND IS MARGINALLY SUPPORTIVE OF SEVERE STORMS IF STORMS CAN
DEVELOP WITHIN THE WARM SECTOR...AND NEAR/ALONG CT RIVER VALLEY WARM
FRONT LATER THIS AFTERNOON. NWLY FLOW AT MIDLEVELS AND WEAK SLY/SELY
FLOW NEAR THE SURFACE WILL RESULT IN LOCALLY SUFFICIENT SHEAR FOR A
FEW STRONGER UPDRAFTS CAPABLE OF GUSTY WINDS AND PERHAPS SOME HAIL.
MAIN LIMITING FACT IS THE LACK OF STRONGER DEEP-LAYER ASCENT AS
PRIMARY SHORTWAVE TROUGH APPEARS TO BE CROSSING THE REGION NOW
FOLLOWED BY NEUTRAL TO WEAK HEIGHT RISES AROUND THE TIME OF MAXIMUM
STORM INITIATION POTENTIAL. NONETHELESS...IF STORMS CAN
DEVELOP...THERE MAY EVOLVE A BRIEF PERIOD OF SEVERE WEATHER IN THE
FORM OF MARGINALLY STRONG WIND GUSTS AND HAIL LATER THIS AFTERNOON.

...NRN ROCKIES...
AN AMPLIFYING MID/UPPER TROUGH ACROSS BC AND THE PACIFIC NORTHWEST
WILL SUPPORT THE INTENSIFICATION OF A SWLY MID/UPPER JET ACROSS THE
NRN ROCKIES THIS PERIOD. HEATING ACROSS THE HIGHER TERRAIN SHOULD
AID IN CONVECTIVE INITIATION LATER THIS AFTERNOON GIVEN DECREASING
STATIC STABILITY AND SUFFICIENT MOISTURE TO SUPPORT MLCAPE ON THE
ORDER OF 500 J/KG. WITH MEAN WIND AROUND 50KT AND MODEST DIRECTIONAL
SHEAR AROUND CLOUD BASE THERE IS THE POSSIBILITY FOR A FEW
FAST-MOVING LOW-TOPPED SUPERCELLS WITH SOME CHANCE FOR HAIL AROUND
AN INCH AND LOCALLY NEAR-SEVERE WIND GUSTS.

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SPC Jul 26, 2015 1730 UTC Day 2 Convective Outlook

SPC 1730Z Day 2 Outlook

Day 2 Outlook Image

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT SUN JUL 26 2015

VALID 271200Z - 281200Z

...THERE IS AN ENH RISK OF SVR TSTMS MONDAY AFTERNOON AND EVENING
ACROSS PARTS OF THE WESTERN AND CENTRAL DAKOTAS...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SURROUNDING AREAS OF THE
NORTHERN INTO CENTRAL PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS AS FAR SOUTH AS THE FRONT RANGE
OF THE ROCKIES INTO ADJACENT AREAS OF THE CENTRAL HIGH PLAINS...AND
AS FAR EAST AS PORTIONS OF THE MIDDLE MISSOURI AND UPPER MISSISSIPPI
VALLEYS...

...SUMMARY...
SEVERE THUNDERSTORMS CAPABLE OF PRODUCING LARGE HAIL...POTENTIALLY
DAMAGING WIND GUSTS...AND PERHAPS A COUPLE OF TORNADOES ARE EXPECTED
MONDAY INTO MONDAY NIGHT ACROSS THE NORTHERN INTO CENTRAL PLAINS.

...SYNOPSIS..
A MID-LEVEL CLOSED LOW...WITHIN A SEASONABLY STRONG UPPER TROUGH
PROGRESSING INLAND ACROSS THE BRITISH COLUMBIA/PACIFIC NORTHWEST
COAST...APPEARS LIKELY TO DIG AS FAR SOUTH AS THE NORTHERN U.S.
ROCKIES BY MIDDAY MONDAY.  THIS FEATURE IS THEN EXPECTED TO TURN
EAST NORTHEASTWARD TOWARD THE CENTRAL CANADIAN/U.S. BORDER AREA
THROUGH THE REMAINDER OF THE PERIOD...AS SUBTROPICAL RIDGING ACROSS
THE SOUTH CENTRAL U.S. REMAINS FAIRLY PROMINENT.  THE CENTER OF THE
RIDGE PROBABLY WILL SHIFT FROM THE SOUTH CENTRAL HIGH PLAINS INTO
THE OZARK PLATEAU REGION...WITH AT LEAST SOME SUPPRESSION OF THE
RIDGE AS FAR SOUTH AS THE CENTRAL ROCKIES INTO NORTH CENTRAL
PLAINS...WHILE A RIDGE AXIS TO THE NORTH GRADUALLY SHIFTS EASTWARD
ACROSS ONTARIO AND THE GREAT LAKES REGION.  AS THIS
OCCURS...DOWNSTREAM TROUGHING IS EXPECTED TO ADVANCE SOUTHEAST OF
THE MID ATLANTIC COAST...BUT WEAK TO MODEST CYCLONIC MID-LEVEL FLOW
PROBABLY WILL PERSIST ACROSS PARTS OF NEW ENGLAND.

IN LOWER-LEVELS...MODELS CONTINUE TO EXHIBIT VARIABILITY CONCERNING
SURFACE CYCLOGENESIS ACROSS THE NORTHERN HIGH PLAINS...THE MOST
PROMINENT FEATURE OF INTEREST.  BUT THE SURFACE LOW CENTER GENERALLY
APPEARS LIKELY TO AT LEAST GRADUALLY DEEPEN BELOW 1000 MB WHILE
MIGRATING NORTHWARD NEAR THE NORTH DAKOTA/MONTANA BORDER AREA DURING
THE DAY...BEFORE MORE RAPID DEEPENING TAKES PLACE MONDAY NIGHT NEAR
THE INTERNATIONAL BORDER AREA INTO SOUTHERN SASKATCHEWAN/MANITOBA. 
AS THIS OCCURS...A COLD FRONT SHOULD SURGE EASTWARD THROUGH MUCH OF
THE NORTHERN PLAINS.  ALTHOUGH HIGHEST MOISTURE CONTENT AIR IS
EXPECTED TO REMAIN WITHIN A REMNANT FRONTAL BAND ACROSS THE
SOUTHWEST ATLANTIC INTO FLORIDA PENINSULA...SEASONABLY MOIST
CONDITIONS SHOULD PERSIST ACROSS MOST AREAS EAST OF THE
ROCKIES...WITH A CONTINUING NORTHWARD SURGE OF HIGHER MOISTURE
CONTENT AIR INTO PORTIONS OF THE NORTHERN PLAINS AND UPPER
MISSISSIPPI VALLEY REGION.

...NORTHERN PLAINS...
BOUNDARY LAYER MOISTENING AND SURFACE HEATING...BENEATH VERY WARM
ELEVATED MIXED LAYER AIR ENCOMPASSING MUCH OF THE PLAINS/MISSISSIPPI
VALLEY REGION...IS EXPECTED TO CONTRIBUTE TO MODERATE TO STRONG
POTENTIAL INSTABILITY IN THE WARM SECTOR OF THE CYCLONE BY LATE
MONDAY AFTERNOON.  AT LEAST WEAK MID-LEVEL COOLING ABOVE THE
ELEVATED MIXED LAYER IS EXPECTED TO CONTRIBUTE TO A NARROW PLUME OF
VERY STEEP MID-LEVEL LAPSE RATES NORTH NORTHEAST OF THE FRONT RANGE
OF THE ROCKIES THROUGH THE HIGHER PLAINS OF THE DAKOTAS...WHERE
MIXED LAYER CAPE OF 2000-4000+ J/KG IS EXPECTED.

ALTHOUGH THE MID-LEVEL COLD CORE...AND STRONGER MID-LEVEL JET...MAY
LAG TO THE WEST OF THE WARM SECTOR THROUGH THE PERIOD...THE FORECAST
THERMODYNAMIC PROFILES...COUPLED WITH MOMENTUM/SHEAR ASSOCIATED WITH
20-40 KT SOUTHERLY LOWER/MID TROPOSPHERIC FLOW...SHOULD PROVE MORE
THAN SUPPORTIVE OF SEVERE STORM DEVELOPMENT.  AIDED BY LARGE-SCALE
FORCING FOR UPWARD VERTICAL MOTION ASSOCIATED WITH THE APPROACHING
UPPER IMPULSE... CONSIDERABLE THUNDERSTORM DEVELOPMENT SEEMS
PROBABLE ALONG THE PRE-FRONTAL SURFACE TROUGH BY 28/00Z...IF NOT
BEFORE.

ISOLATED SUPERCELLS MAY NOT BE OUT OF THE QUESTION INITIALLY...
PARTICULARLY IN THE VICINITY OF THE WARM FRONT NEAR THE NORTH
DAKOTA/SASKATCHEWAN BORDER.  HOWEVER...THE UPSCALE GROWTH OF SEVERAL
STORM CLUSTERS...WHICH COULD GRADUALLY ATTEMPT TO CONSOLIDATE
THROUGH MID TO LATE EVENING APPEARS MOST PROBABLE... PRIMARILY
ACCOMPANIED BY A SEVERE WIND/HAIL THREAT.

..KERR.. 07/26/2015

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SPC Jul 26, 2015 1630 UTC Day 1 Convective Outlook

SPC 1630Z Day 1 Outlook

Day 1 Outlook Image

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT SUN JUL 26 2015

VALID 261630Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE CNTRL HIGH PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS OVER THE NRN AND CNTRL HIGH
PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS FROM THE MIDWEST/NORTH OF OH
VALLEY TO ALLEGHENY PLATEAU TO THE NORTHEAST...

...THERE IS A MRGL RISK OF SVR TSTMS OVER THE NRN ROCKIES/WRN-CNTRL
MT...

...SUMMARY...
WIDELY SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED MAINLY
THIS AFTERNOON AND EVENING ACROSS PORTIONS OF THE HIGH
PLAINS...MIDDLE MISSISSIPPI/LOWER OHIO VALLEYS...AND NORTHEAST
STATES.

...CNTRL/NRN HIGH PLAINS...
MORNING SATELLITE IMAGERY DEPICTS MOSTLY CLEAR SKIES ACROSS THE HIGH
PLAINS FROM THE RIO GRANDE TO CANADIAN BORDER. DIURNAL
HEATING/MIXING AND WEAK BACKGROUND ASCENT/HEIGHT FALLS FROM ERN CO
NWD SHOULD CONTRIBUTE TO WIDELY SCATTERED CONVECTIVE INITIATION
ALONG/AHEAD OF HIGH PLAINS LEE/THERMAL TROUGH LATER THIS AFTERNOON.
DESPITE VERY WARM MID-LEVEL TEMPS DELINEATING LOWER LAYER OF EML
PLUME...DEEPER BOUNDARY LAYER MIXING/HEATING SHOULD BE ABLE TO AID
IN OVERCOMING CONVECTIVE INHIBITION WITH AT LEAST A FEW STORMS ABLE
TO TAP INTO STRONG SURFACE-BASED INSTABILITY. EFFECTIVE SHEAR ON THE
ORDER OF 25-30KT SHOULD SUPPORT A COUPLE OF MORE PERSISTENT STORM
UPDRAFTS/SUPERCELLS WITH THE CAPABILITY OF PRODUCING HAIL AND HIGH
WINDS. SOMEWHAT GREATER STORM COVERAGE AND PERSISTENCE MAY EXIST
ACROSS ERN CO WHERE STORMS MAY DRIFT TOWARD AXIS OF GREATER LOW
LEVEL MOISTURE/DESTABILIZATION ALONG THE CO/KS BORDER WITH TIME.
SOME OF THIS ACTIVITY MAY ALSO PERSIST INTO THE NIGHTTIME HOURS AS
MASS TRANSPORT AND LOW LEVEL ASCENT ARE MAXIMIZED ON THE NOSE OF
PLAINS LLJ.

...MIDWEST/TO NORTH OF OH VALLEY/ALLEGHENY PLATEAU...
FORECAST IS COMPLICATED ACROSS THE MIDWEST GIVEN THE DECAYING
REMNANTS OF A PAIR OF OVERNIGHT MCS/S...ONE NOW CROSSING THE LOWER
OH RIVER VALLEY IN WRN KY AND THE MO BOOTHEEL...THE OTHER MOVING
INTO WRN IL FROM SERN IA AND ERN MO. NRN SYSTEM APPEARS TO BE
ASSOCIATED WITH A RELATIVELY STRONG SHORTWAVE TROUGH EVIDENT ON
WATER VAPOR SATELLITE IMAGERY OVER MN/IA...AND A PACKET OF STRONGER
30-35 KT MIDLEVEL FLOW PER REGIONAL VWP OBSERVATIONS.

STRONG HEATING IN THE WAKE OF THE SHORTWAVE/MCV ACROSS MN/IA WILL
CONTRIBUTE TO AN AXIS OF STRONG INSTABILITY ALONG THE EDGE OF THE
PLAINS CAPPING INVERSION/EML. WHILE LARGE SCALE SUPPORT FOR ASCENT
WILL PROBABLY BE WANING ALONG THIS CORRIDOR...A CONDITIONAL SEVERE
HAIL/WIND RISK WILL BE MAINTAINED IN THE EVENT ISOLATED STORMS CAN
DEVELOP GIVEN CONTINUING LOW LEVEL CONVERGENCE ALONG RESIDUAL FRONT
AND OUTFLOW BOUNDARIES REMAINING IN THE PRESENCE OF STRONG TO
LOCALLY EXTREME DESTABILIZATION.

FARTHER EAST....FROM IND TO PA...INSTABILITY AND WEAK LIFT WILL BE
FOCUSED ALONG THE STALLED FRONT SITUATED ACROSS THESE AREAS. A FEW
AFTERNOON OR EARLY EVENING STORMS COULD RESULT IN LOCALLY STRONG
GUSTS AND PERHAPS A COUPLE OF TREE-DOWN EVENTS.

...NORTHEAST...
MODEST WARM SECTOR DESTABILIZATION WAS UNDERWAY WITH LATEST
OBJECTIVE DATA INDICATING MLCAPE OF AROUND 1000 J/KG ACROSS MUCH OF
NY AND LITTLE IN THE WAY OF INHIBITION. LARGE SCALE PATTERN ACROSS
NEW ENGLAND IS MARGINALLY SUPPORTIVE OF SEVERE STORMS IF STORMS CAN
DEVELOP WITHIN THE WARM SECTOR...AND NEAR/ALONG CT RIVER VALLEY WARM
FRONT LATER THIS AFTERNOON. NWLY FLOW AT MIDLEVELS AND WEAK SLY/SELY
FLOW NEAR THE SURFACE WILL RESULT IN LOCALLY SUFFICIENT SHEAR FOR A
FEW STRONGER UPDRAFTS CAPABLE OF GUSTY WINDS AND PERHAPS SOME HAIL.
MAIN LIMITING FACT IS THE LACK OF STRONGER DEEP-LAYER ASCENT AS
PRIMARY SHORTWAVE TROUGH APPEARS TO BE CROSSING THE REGION NOW
FOLLOWED BY NEUTRAL TO WEAK HEIGHT RISES AROUND THE TIME OF MAXIMUM
STORM INITIATION POTENTIAL. NONETHELESS...IF STORMS CAN
DEVELOP...THERE MAY EVOLVE A BRIEF PERIOD OF SEVERE WEATHER IN THE
FORM OF MARGINALLY STRONG WIND GUSTS AND HAIL LATER THIS AFTERNOON.

...NRN ROCKIES...
AN AMPLIFYING MID/UPPER TROUGH ACROSS BC AND THE PACIFIC NORTHWEST
WILL SUPPORT THE INTENSIFICATION OF A SWLY MID/UPPER JET ACROSS THE
NRN ROCKIES THIS PERIOD. HEATING ACROSS THE HIGHER TERRAIN SHOULD
AID IN CONVECTIVE INITIATION LATER THIS AFTERNOON GIVEN DECREASING
STATIC STABILITY AND SUFFICIENT MOISTURE TO SUPPORT MLCAPE ON THE
ORDER OF 500 J/KG. WITH MEAN WIND AROUND 50KT AND MODEST DIRECTIONAL
SHEAR AROUND CLOUD BASE THERE IS THE POSSIBILITY FOR A FEW
FAST-MOVING LOW-TOPPED SUPERCELLS WITH SOME CHANCE FOR HAIL AROUND
AN INCH AND LOCALLY NEAR-SEVERE WIND GUSTS.

..CARBIN/GLEASON.. 07/26/2015

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SPC Jul 26, 2015 1300 UTC Day 1 Convective Outlook

SPC 1300Z Day 1 Outlook

Day 1 Outlook Image

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0754 AM CDT SUN JUL 26 2015

VALID 261300Z - 271200Z

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

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE HIGH PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE MIDWEST AND MIDDLE
MS RIVER/LOWER OH VALLEYS...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PORTIONS OF THE
NORTHEAST STATES...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PORTIONS OF MT...

...SUMMARY...
WIDELY SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED MAINLY
THIS AFTERNOON AND EVENING ACROSS PORTIONS OF THE HIGH
PLAINS...MIDDLE MISSISSIPPI/LOWER OHIO VALLEYS...AND NORTHEAST
STATES.

...SYNOPSIS...
AN AMPLIFICATION OF THE WESTERLIES OVER THE NORTHERN HALF OF THE
CONUS IS EXPECTED THROUGH TONIGHT. ON THE NORTHERN PERIPHERY OF A
SOUTHERN PLAINS UPPER RIDGE...MULTIPLE LOW-AMPLITUDE/CONVECTIVELY
RELATED MID-LEVEL DISTURBANCES WILL SPREAD GENERALLY
EAST-SOUTHEASTWARD ACROSS THE CENTRAL PLAINS/LOWER MO
VALLEY/MIDWEST...ALL WHILE A MORE SUBSTANTIAL UPPER TROUGH
AMPLIFIES/DIGS SOUTHEASTWARD OVER THE PACIFIC NORTHWEST/GREAT BASIN
THROUGH TONIGHT.

...CENTRAL HIGH PLAINS...
ON THE IMMEDIATE NORTHERN PERIPHERY OF THE SOUTHERN HIGH
PLAINS-CENTERED UPPER RIDGE...HIGH-BASED THUNDERSTORMS SHOULD
INITIALLY DEVELOP ACROSS SOUTHERN/EASTERN CO THIS AFTERNOON...WITH
SUBSEQUENT INTENSIFICATION EXPECTED AS THEY MOVE EAST-NORTHEASTWARD
ACROSS FAR EASTERN CO AND EVENTUALLY FAR WESTERN KS INTO A HOT/MORE
MOIST BOUNDARY LAYER. IT IS PROBABLE THAT STORMS WILL TEND TO
CLUSTER BY EARLY EVENING INTO A SLOW EAST/NORTHEASTWARD PROPAGATING
MCS...WITH THE AID OF A NOCTURNALLY INCREASING /30+ KT/ SOUTHERLY
LOW-LEVEL JET. EPISODIC BOUTS SEVERE WIND/HAIL WILL LIKELY BE THIS
AFTERNOON/EVENING...WITH AN INCREASINGLY MORE MARGINAL SEVERE RISK
BY THE LATE EVENING/OVERNIGHT HOURS.

...DAKOTAS/NEB...
WHILE OVERALL FORCING WILL BE WEAK UNDER THE INFLUENCE OF RISING
UPPER HEIGHTS...WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED TO
DEVELOP ACROSS PARTS OF THE DAKOTAS/WESTERN NEB IN VICINITY OF A LEE
TROUGH. WHILE SOMEWHAT STRONGER VERTICAL SHEAR /30-35 KT EFFECTIVE/
WILL RESIDE OVER THE DAKOTAS...AN OVERALL SCENARIO CHARACTERIZED BY
MODEST FORCING/VERTICAL SHEAR SUGGESTS THAT CONVECTION WILL NOT BE
PARTICULARLY ORGANIZED...ALTHOUGH ISOLATED INSTANCES OF HAIL/WIND
WILL NONETHELESS BE POSSIBLE. 

...MT...
THE LEADING EDGE OF HEIGHT FALLS/FORCING FOR ASCENT RELATED TO THE
AMPLIFYING PACIFIC NORTHWEST UPPER TROUGH WILL REACH PORTIONS OF MT
LATER TODAY INTO TONIGHT. HIGH-BASED THUNDERSTORMS SHOULD
DEVELOP/INCREASE THROUGH MID/LATE AFTERNOON ACROSS CENTRAL MT AND
SUBSEQUENTLY SPREAD EAST-NORTHEASTWARD. GIVEN AN ENVIRONMENT
CHARACTERIZED BY INCREASINGLY STRONG DEEP-LAYER SOUTHWESTERLY WINDS
ATOP DRY/WELL-MIXED BOUNDARY LAYERS...SOME OF THE STRONGER
HIGH-BASED STORMS MAY BE CAPABLE OF SEVERE-CALIBER WIND GUSTS AND
POSSIBLY SMALL HAIL LATE THIS AFTERNOON/EVENING. IT IS NOT ENTIRELY
OUT OF THE QUESTION THAT A FEW OF THESE STORMS WILL DEVELOP
INTO/ACROSS FAR EASTERN MT LATE TONIGHT WITHIN A
WESTWARD-TRANSITIONING MOIST AXIS.
 
...MIDWEST/OZARKS AND MIDDLE MS/LOWER OH RIVER VALLEYS...
DUAL ELEVATED MCS/S AND WHAT APPEAR TO BE RELATED MCV/S ARE
PROGRESSING SOUTHEASTWARD EARLY THIS MORNING ACROSS THE
REGION...INCLUDING ONE ACROSS SOUTHEAST MO/SOUTHERN IL AND THE OTHER
ACROSS SOUTHERN/EASTERN IA AND NORTHERN MO AS OF 13Z/8AM CDT. ANY
SEVERE RISK SHOULD REMAIN MINIMAL EARLY TODAY...BUT SOME
REINVIGORATION IS POSSIBLE ACROSS THE REGION PARTICULARLY ON THE
WESTERN/SOUTHERN FLANKS OF THE EARLY DAY STORMS WHERE
DESTABILIZATION WILL BE MORE CONSEQUENTIAL. SOME HAIL AND ISOLATED
DAMAGING WINDS WILL BE POSSIBLE. 

FARTHER NORTH...WHILE THE EARLY DAY MCS/OUTFLOW CASTS SOME
UNCERTAINTY...THERE IS SOME POTENTIAL THAT STORMS MAY REDEVELOP LATE
THIS AFTERNOON/EVENING ACROSS PARTS OF IA/SOUTHERN MN IN VICINITY OF
A WARM FRONT/RESIDUAL OUTFLOW. WHILE UPPER-LEVEL HEIGHTS WILL BE
RISING AND OVERALL FORCING WILL BE WEAK...SEVERE THUNDERSTORMS WILL
BE POSSIBLE IF DEEP CONVECTION CAN DEVELOP/REMAIN SUSTAINED WITHIN
WHAT SHOULD BE A VERY UNSTABLE ENVIRONMENT.

...NEW ENGLAND/EASTERN NY...
AHEAD OF A COLD FRONT...THE AIR MASS SHOULD AT LEAST MODESTLY
DESTABILIZE INTO THIS AFTERNOON IN THE WAKE OF THICKER CLOUD COVER
AND SCATTERED PRECIPITATION THIS MORNING. WHILE LARGER-SCALE FORCING
WILL BE WEAK/NEBULOUS...AT LEAST WIDELY SCATTERED THUNDERSTORMS
SHOULD REDEVELOP LATER THIS AFTERNOON...WITH SOME STRONGER STORMS
POSSIBLE AS HEATING/DESTABILIZATION OCCURS. RELATIVELY WEAK
DEEP-LAYER SHEAR /20-30 KT EFFECTIVE/ AND WEAK MID-LEVEL LAPSE RATES
SHOULD TEMPER THE OVERALL SEVERE POTENTIAL...BUT SOME STRONGER WIND
GUSTS/MARGINAL HAIL WILL NONETHELESS BE POSSIBLE THIS
AFTERNOON/EARLY EVENING.

..GUYER/COOK.. 07/26/2015

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SPC Jul 26, 2015 Day 4-8 Severe Weather Outlook

Day 4-8 Outlook

Day 4-8 Outlook Image

DAY 4-8 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0347 AM CDT SUN JUL 26 2015

VALID 291200Z - 031200Z

...DISCUSSION...
UPPER LEVEL HIGH PRESSURE WILL EXTEND FROM THE SOUTHERN PLAINS
WESTWARD ACROSS THE SOUTHWEST U.S. FOR MUCH OF THE DAY 4-8 PERIOD.
AN UPPER LEVEL LOW NEAR THE MINNESOTA/ONTARIO BORDER WILL LIFT
NORTHWARD WEDNESDAY/THURSDAY AND STRONGER MID-LEVEL WIND FIELDS WILL
ALSO TEMPORARILY SHIFT NORTH INTO CANADA. A SURFACE COLD FRONT WILL
MOVE EAST ACROSS THE GREAT LAKES/OHIO VALLEY REGION WEDNESDAY AND
NEW ENGLAND ON THURSDAY...LIKELY ACCOMPANIED BY AT LEAST SCATTERED
THUNDERSTORMS. AN ISOLATED SEVERE THREAT IS POSSIBLE
WEDNESDAY/THURSDAY GIVEN DEW POINTS THAT WILL LIKELY BE IN THE UPPER
60S/LOWER 70S RESULTING IN MODERATE SURFACE-BASED INSTABILITY.
HOWEVER...DEEP SHEAR IS FORECAST TO BE AT OR BELOW 25 KTS WHICH
SHOULD TEMPER THE OVERALL RISK.

ELSEWHERE...LOW-LEVEL MOISTURE WILL QUICKLY RETURN THROUGH THE
CENTRAL/NORTHERN PLAINS IN THE WAKE OF THE FRONTAL PASSAGE EARLY IN
THE WEEK AS AN ELEVATED MIXED LAYER BECOMES RE-ESTABLISHED FROM THE
NORTHERN ROCKIES EAST INTO THE CENTRAL/NORTHERN PLAINS. THE SEVERE
RISK MAY INCREASE TOWARDS THE END OF THE WEEK ACROSS THE NORTHERN
ROCKIES INTO THE UPPER MIDWEST WHERE MODERATELY STRONG
WEST-NORTHWEST UPPER-LEVEL FLOW WILL EXIST. 

WHILE PREDICTABILITY IS CURRENTLY TOO LOW TO ASSIGN 15 PERCENT DAILY
RISK AREAS...LATER OUTLOOKS MAY CONTAIN AT LEAST MARGINAL RISK
AREAS/5 PERCENT PROBABILITIES FOR THESE SCENARIOS.

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SPC Jul 26, 2015 0730 UTC Day 3 Severe Thunderstorm Outlook

SPC 0730Z Day 3 Outlook

Day 3 Outlook Image

DAY 3 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0220 AM CDT SUN JUL 26 2015

VALID 281200Z - 291200Z

...THERE IS A MRGL RISK OF SVR TSTMS OVER MUCH OF THE UPPER
MIDWEST...

...SUMMARY...
ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE TUESDAY OVER PORTIONS
OF THE UPPER MIDWEST.

...SYNOPSIS...
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE EAST ALONG THE
U.S.-CANADIAN BORDER TUESDAY...WITH AN ELONGATED UPPER-LEVEL HIGH
OVER MUCH OF THE SOUTHERN HALF OF THE CONUS.  A COLD FRONT WILL MOVE
FROM THE NORTHERN PLAINS ACROSS MUCH OF THE UPPER
MIDWEST...EXTENDING FROM CENTRAL MINNESOTA SOUTHWEST INTO THE
OKLAHOMA PANHANDLE TUESDAY EVENING.

...UPPER MIDWEST...
THUNDERSTORMS WILL LIKELY BE IN PROGRESS ACROSS PORTIONS OF THE
UPPER MIDWEST TUESDAY MORNING AIDED BY A STRONG NOCTURNAL LOW-LEVEL
JET/WARM ADVECTION. DESPITE EARLY CLOUD COVER...THE PRESENCE OF A
RESIDUAL ELEVATED MIXED LAYER AND DIURNAL HEATING OF A VERY MOIST
AIR MASS /LOWER 70S SURFACE DEW POINTS/ SHOULD RESULT IN SUBSTANTIAL
DESTABILIZATION BY LATE AFTERNOON. STRONGER FLOW ALOFT WILL REMAIN
WEST OF THE COLD FRONT UNTIL TUESDAY EVENING...WHEN HEIGHT
FALLS/FORCING FOR ASCENT SHOULD INCREASE ACROSS THE AREA. 
THUNDERSTORMS DEVELOPING NEAR THE FRONT...AND POSSIBLY
REINTENSIFICATION OF ONGOING STORMS...DURING THE AFTERNOON/EVENING
WILL POSE A RISK OF AT LEAST ISOLATED DAMAGING WINDS AND LARGE HAIL.
HIGHER SEVERE PROBABILITIES MAY EVENTUALLY BE WARRANTED AS THE
EFFECTS OF EARLY DAY STORMS/MESOSCALE DETAILS BECOME CLEARER.

..BUNTING.. 07/26/2015

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SPC Jul 26, 2015 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook

Day 1 Outlook Image

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1237 AM CDT SUN JUL 26 2015

VALID 261200Z - 271200Z

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE HIGH PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS OVER THE MID MS/LOWER OH
VALLEY...

...SUMMARY...
WIDELY SCATTERED STRONG TO SEVERE THUNDERSTORM ACTIVITY IS POSSIBLE
SUNDAY INTO SUNDAY NIGHT ACROSS PARTS OF THE NORTHERN AND CENTRAL
HIGH PLAINS...AND PORTIONS OF THE MIDDLE MISSISSIPPI/LOWER OHIO
VALLEY REGION.

...HIGH PLAINS...

WEAK MID-LEVEL HEIGHT RISES ARE EXPECTED THROUGH THE FIRST HALF OF
THE DAY1 PERIOD ACROSS THE PLAINS BEFORE STRONG FORCING AND HEIGHT
FALLS SPREAD INTO THE NRN INTER-MOUNTAIN REGION BY SUNRISE MONDAY
MORNING.  GIVEN THE LACK OF LARGE-SCALE SUPPORT...BOUNDARY-LAYER
HEATING WILL PROVE INSTRUMENTAL IN THUNDERSTORM DEVELOPMENT ACROSS
THE HIGH PLAINS...MUCH OF IT SHOULD REMAIN WIDELY SCATTERED IN
NATURE.  ONE REGION WHERE STORMS MAY CONGREGATE SOMEWHAT IS ACROSS
ERN CO INTO NWRN KS.  LATEST MODEL GUIDANCE SUGGESTS VERY WEAK
DISTURBANCES MAY ROTATE NEWD WITHIN MOIST PLUME ACROSS NM INTO THE
CNTRL HIGH PLAINS...SIMILAR TO SATURDAY.  STRONG HEATING ACROSS THE
HIGHER TERRAIN IS EXPECTED TO AID TSTM DEVELOPMENT THAT WOULD TRACK
NEWD ALONG WEAK SW-NE ORIENTED SFC BOUNDARY THAT WILL REMAIN DRAPED
FROM SERN CO INTO NWRN KS.  FORECAST SOUNDINGS SUGGEST HIGH-BASED
CONVECTION WILL EVOLVE BY LATE AFTERNOON ALONG THE NM/CO BORDER AND
SPREAD DOWNSTREAM WITHIN MODEST SWLY FLOW ALOFT.  WHILE A FEW WEAK
SUPERCELLS MAY BE NOTED ALONG THIS CORRIDOR...SHEAR/INSTABILITY DO
NOT APPEAR SUFFICIENT TO WARRANT MORE THAN 5 PERCENT SEVERE PROBS
FOR HAIL/WIND.  INCREASING LLJ OVER SWRN KS AFTER DARK MAY SUPPORT
CLUSTERING AND PERHAPS A SMALL MCS.

FARTHER NORTH...A FEW THUNDERSTORMS MAY DEVELOP DURING THE HEAT OF
THE DAY ALONG LEE TROUGH EXTENDING NWD ACROSS WRN NEBRASKA INTO WRN
ND.  GIVEN THE LACK OF FORCING THIS ACTIVITY SHOULD REMAIN SPARSE
AND NOT PARTICULARLY ORGANIZED.


...MID MS/LOWER OH VALLEY...

LONG-LIVED MCS IS PROGRESSING SEWD ACROSS SERN SD/SWRN MN/NWRN IA AT
ROUGHLY 30KT.  REMNANTS OF THIS COMPLEX OF STORMS SHOULD PROPAGATE
ACROSS THE MID MS VALLEY AND PERHAPS MOVE INTO NRN MO BY DAYBREAK. 
LATEST SHORT-RANGE GUIDANCE SUGGESTS SOME OF THIS
ACTIVITY...POSSIBLY SUPPORTED BY A CONVECTIVELY INDUCED VORT...COULD
REGENERATE OVER MO/IL BY MID DAY AS BOUNDARY LAYER WARMS AND CINH
WEAKENS.  GUSTY WINDS AND PERHAPS SOME HAIL WOULD BE THE PRIMARY
THREATS WITH STORMS THAT EVOLVE ALONG DIFFERENTIAL HEATING/OUTFLOW
BOUNDARIES.

..DARROW/DEAN.. 07/26/2015

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SPC Jul 26, 2015 0600 UTC Day 2 Convective Outlook

SPC 0600Z Day 2 Outlook

Day 2 Outlook Image

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1244 AM CDT SUN JUL 26 2015

VALID 271200Z - 281200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF EASTERN
MONTANA/WESTERN NORTH DAKOTA...

...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLIGHT RISK
AREA OVER PORTIONS OF THE CENTRAL/NORTHERN PLAINS AND UPPER
MIDWEST...

...SUMMARY...
SEVERE THUNDERSTORMS WILL BE POSSIBLE MONDAY OVER PORTIONS OF THE
CENTRAL AND NORTHERN PLAINS AND UPPER MIDWEST.

...SYNOPSIS...
A SEASONABLY STRONG UPPER TROUGH WILL MOVE ACROSS THE NORTHERN
ROCKIES MONDAY AS A WEAK TROUGH MOVES SLOWLY EASTWARD ALONG THE EAST
COAST. SURFACE LOW PRESSURE WILL DEEPEN FROM EASTERN MONTANA INTO
WESTERN NORTH DAKOTA AS AN ASSOCIATED COLD FRONT MOVES ACROSS THE
NORTHERN PLAINS.

...CENTRAL/NORTHERN PLAINS INTO UPPER MIDWEST...
A FEW ELEVATED STRONG/SEVERE STORMS MAY BE IN PROGRESS EARLY MONDAY
ACROSS NORTHEAST MONTANA/NORTHWEST NORTH DAKOTA AS A LEAD SHORTWAVE
TROUGH LIFTS NORTHEAST IN ADVANCE OF THE PRIMARY UPPER LEVEL TROUGH.
LARGE HAIL WOULD BE THE MAIN THREAT WITH EARLY DAY STORMS. 

AS THE SURFACE LOW DEEPENS OVER EASTERN MONTANA DURING THE DAY...A
MOIST LOW-LEVEL EASTERLY FLOW /SURFACE DEW POINTS 60-65/ WILL
DEVELOP NORTH OF THE LOW AND A FRONTAL BOUNDARY EXTENDING NORTHEAST
FROM THE LOW INTO NORTH-CENTRAL NORTH DAKOTA. WITH STEEP MID-LEVEL
LAPSE RATES IN PLACE...MODERATE/STRONG SURFACE-BASED INSTABILITY
SHOULD EXIST BY AFTERNOON. STRENGTHENING MID-LEVEL FLOW ABOVE
LOW-LEVEL EASTERLIES WILL RESULT IN A STRONGLY SHEARED ENVIRONMENT
/0-6 KM SHEAR 45-55 KTS/. AS HEIGHT FALLS/FORCING FOR ASCENT
OVERSPREAD THE AREA DURING THE AFTERNOON...THUNDERSTORMS ARE
EXPECTED TO DEVELOP OVER NORTHEAST MONTANA/NORTHWEST NORTH DAKOTA
WITH SUPERCELLS LIKELY AND A RISK FOR LARGE HAIL AND DAMAGING WINDS.
DESPITE MARGINAL LCL HEIGHTS...SOME TORNADO RISK MAY EXIST WHERE
BACKED LOW-LEVEL FLOW CONTRIBUTES TO ENHANCED 0-3 KM STORM-RELATIVE
HELICITY. 

FARTHER SOUTH...THUNDERSTORM DEVELOPMENT IS POSSIBLE DURING THE
AFTERNOON IN ADVANCE OF THE COLD FRONT ALONG A NORTH-SOUTH SURFACE
TROUGH AS FAR SOUTH AS NORTHWESTERN KANSAS...HOWEVER THE PRESENCE OF
AN ELEVATED MIXED LAYER/POTENTIAL CAPPING CONCERNS CAST SOME DOUBT
ON COVERAGE. INTENSE HEATING WILL RESULT IN MODERATE/STRONG
INSTABILITY AND WITH 30-40 KTS OF SHEAR...STORMS THAT DO DEVELOP
WOULD CARRY SOME RISK OF MAINLY DAMAGING WINDS. THUNDERSTORM
COVERAGE MAY INCREASE SOMEWHAT MONDAY EVENING AS A NOCTURNALLY
STRENGTHENING LOW-LEVEL JET RESULTS IN STRONG WARM ADVECTION ACROSS
THE CENTRAL/NORTHERN PLAINS...AND AN IMPULSE WITHIN SOUTHWEST FLOW
ALOFT MOVES ACROSS THE DAKOTAS/WESTERN MINNESOTA. DAMAGING WINDS
WOULD BE THE PRIMARY SEVERE THREAT...WITH SOME SEVERE HAIL POSSIBLE.

..BUNTING.. 07/26/2015

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SPC MD 1538

MD 1538 CONCERNING SEVERE THUNDERSTORM WATCH 451… FOR KS…NRN MO

MD 1538 Image


MESOSCALE DISCUSSION 1538
NWS STORM PREDICTION CENTER NORMAN OK
0932 PM CDT SAT JUL 25 2015

AREAS AFFECTED...KS...NRN MO

CONCERNING...SEVERE THUNDERSTORM WATCH 451...

VALID 260232Z - 260400Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 451
CONTINUES.

SUMMARY...SEVERE THREAT MAY LINGER FOR ANOTHER 1-2 HOURS ON WESTERN
AND NORTHEASTERN EDGE OF WW 451...BUT A GENERAL DOWNWARD TREND IS
EXPECTED WITH TIME AND NO ADDITIONAL WATCH ISSUANCE IS ANTICIPATED
DOWNSTREAM.

DISCUSSION...THE STRONGEST CONVECTION ACROSS WW 451 AS OF 0230Z IS
IN THE FAR WRN PART ACROSS W-CNTRL KS AND THE FAR NERN PORTION
ACROSS NWRN MO. ACROSS FAR NERN KS/NWRN MO...TWO RELATIVELY
ORGANIZED CONVECTIVE CLUSTERS HAVE EVOLVED OUT OF EARLIER ELEVATED
CONVECTION. THESE CLUSTERS WILL AFFECT THE FAR NERN PORTION OF WW
451 AND AREAS DOWNSTREAM INTO NRN MO. THIS ACTIVITY IS LIKELY BEING
AIDED BY ASCENT ATTENDANT TO A SHORTWAVE CURRENTLY MOVING ACROSS IA
AND MAY PERSIST INTO THE OVERNIGHT HOURS AS IT MOVES ESEWD. IN THE
SHORT TERM...THIS ACTIVITY WILL POSE A THREAT OF LOCALLY DAMAGING
WIND...BUT DECREASING SFC-BASED BUOYANCY WITH TIME SHOULD TEMPER THE
OVERALL SEVERE THREAT AND NO DOWNSTREAM WW ISSUANCE IS ANTICIPATED
AT THIS TIME. 

TO THE WEST...STRONG STORMS ARE ONGOING TO THE NE OF DDC...WITH SOME
BACKBUILDING NOTED ALONG A TRAILING OUTFLOW BOUNDARY. LARGE-SCALE
ASCENT IS NEUTRAL AT BEST IN THIS REGION...SO THIS ACTIVITY SHOULD
BECOME LESS ORGANIZED WITH TIME AS THE THERMODYNAMIC ENVIRONMENT
BECOMES INCREASINGLY UNFAVORABLE. WHILE A LOCAL EXTENSION IN TIME IS
POSSIBLE DEPENDING ON SHORT-TERM TRENDS...NEW WATCH ISSUANCE IS NOT
ANTICIPATED.

..DEAN/HART.. 07/26/2015

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LSX...EAX...TOP...ICT...GID...DDC...

LAT...LON   37739938 37730030 37820055 38240072 38779988 39209842
            39439697 39939524 40189320 40079264 39619171 39059183
            38829319 38349476 38099635 37829812 37739938 

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