SPC MD 1591

MD 1591 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR SOUTHERN IOWA AND NORTHERN MISSOURI

MD 1591 Image


MESOSCALE DISCUSSION 1591
NWS STORM PREDICTION CENTER NORMAN OK
0622 PM CDT SUN AUG 02 2015

AREAS AFFECTED...SOUTHERN IOWA AND NORTHERN MISSOURI

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 022322Z - 030015Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...THUNDERSTORMS ARE DEVELOPING ALONG A COLD FRONT WITHIN A
VERY UNSTABLE ATMOSPHERE. LARGE HAIL AND DAMAGING WINDS WILL BE
POSSIBLE WITH THE STRONGEST THUNDERSTORMS. HOWEVER...THIS THREAT IS
EXPECTED TO DIMINISH AFTER THE NEXT 2-3 HOURS. AS SUCH...A WATCH IS
NOT ANTICIPATED AT THIS TIME...BUT WILL CONTINUE TO BE ASSESSED.

DISCUSSION...THUNDERSTORMS ARE DEVELOPING/STRENGTHENING...ALONG A
SLOWLY SOUTHWARD-MOVING COLD FRONT. AHEAD OF THE COLD
FRONT...SURFACE TEMPERATURES HAVE WARMED INTO THE UPPER-80S TO
LOW-90S F WITH DEW POINT TEMPERATURES IN THE LOW-T0-MID 70S F.
THIS...COUPLED WITH STEEP MID-LEVEL LAPSE RATES HAVE COMBINED TO
YIELD MUCAPE VALUES ABOVE 4000 J/KG. ADDITIONALLY...THIS AREA IS ON
THE SOUTHERN EDGE OF THE STRONGER MID-LEVEL FLOW RESULTING IN
DEEP-LAYER SHEAR VALUES ON THE ORDER OF 35 KTS. THE COMBINATION OF
CAPE AND DEEP-LAYER SHEAR IN THE PRESENCE OF CONVERGENCE ALONG THE
SURFACE-COLD FRONT WILL SUPPORT CONTINUED THUNDERSTORM DEVELOPMENT
IN THE NEAR TERM...WITH LARGE HAIL/DAMAGING WINDS POSSIBLE WITH THE
STRONGEST THUNDERSTORM CORES. 

HOWEVER...CONVERGENCE ALONG THE COLD FRONT IS EXPECTED TO WEAKEN
WITH TIME...AND THE LOSS OF DAY-TIME HEATING AND LOWER SURFACE DEW
POINT TEMPERATURES TO THE SOUTH /ACROSS MISSOURI/ WILL CONTRIBUTE TO
A WEAKENING OF THE OVERALL INSTABILITY. AS SUCH...IT APPEARS THERE
MAY ONLY BE A BRIEF WINDOW OF OPPORTUNITY FOR THUNDERSTORMS TO HAVE
A SUSTAINED LARGE HAIL/DAMAGING WIND THREAT. A WATCH IS NOT
ANTICIPATED AT THIS TIME...ALTHOUGH TRENDS WILL CONTINUE TO BE
ASSESSED.

..MARSH/CORFIDI.. 08/02/2015

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

ATTN...WFO...LSX...DVN...DMX...EAX...OAX...TOP...GID...

LAT...LON   41169762 41509674 41799335 41619202 40909148 40129165
            39879332 39889541 40339703 40629771 41169762 

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SPC MD 1582

MD 1582 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF CNTRL/WRN MN…ERN ND

MD 1582 Image


MESOSCALE DISCUSSION 1582
NWS STORM PREDICTION CENTER NORMAN OK
0616 AM CDT SUN AUG 02 2015

AREAS AFFECTED...PORTIONS OF CNTRL/WRN MN...ERN ND

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 021116Z - 021345Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...ISOLATED SVR-HAIL POTENTIAL WILL EXIST EARLY THIS
MORNING...THOUGH WW ISSUANCE IS NOT ANTICIPATED.

DISCUSSION...A RECENT UPSWING IN CONVECTION HAS OCCURRED ACROSS
PARTS OF ERN ND INTO NWRN MN WITHIN A BAND OF ASCENT RELATED TO A
MID-LEVEL SPEED MAX CROSSING THE REGION PER WATER-VAPOR IMAGERY.
CLOUD-TOP COOLING IMPLIED BY IR IMAGERY HIGHLIGHTS THE WWD
DEVELOPMENT OF CONVECTION INTO THE REGION...WHERE A FEED OF ELEVATED
INSTABILITY IS BEING MAINTAINED FROM THE W. TSTMS WILL CONTINUE
SPREADING SEWD ACROSS THE REGION THROUGH THE EARLY MORNING HOURS
AMIDST MUCAPE AROUND 500-1000 J/KG. ISOLATED MARGINALLY SVR HAIL MAY
OCCUR...AIDED BY AROUND 50 KT OF DEEP SHEAR SAMPLED BY THE MVX VWP.
HOWEVER...WITH STRONGER ELEVATED BUOYANCY DISPLACED ESEWD ACROSS THE
REGION TOWARD THE UPPER MS RIVER AND POINTS EWD...THE SVR-HAIL RISK
SHOULD REMAIN ISOLATED/MARGINAL.

..COHEN/EDWARDS.. 08/02/2015

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

ATTN...WFO...DLH...MPX...FGF...

LAT...LON   46999736 47489548 46819449 45919539 46119687 46999736 

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SPC MD 1566

MD 1566 CONCERNING SEVERE THUNDERSTORM WATCH 459… FOR NERN KS THROUGH EXTREME SERN NEB…SRN IA…NRN MO AND EXTREME WCNTRL IL

MD 1566 Image


MESOSCALE DISCUSSION 1566
NWS STORM PREDICTION CENTER NORMAN OK
0804 PM CDT TUE JUL 28 2015

AREAS AFFECTED...NERN KS THROUGH EXTREME SERN NEB...SRN IA...NRN MO
AND EXTREME WCNTRL IL

CONCERNING...SEVERE THUNDERSTORM WATCH 459...

VALID 290104Z - 290300Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 459
CONTINUES.

SUMMARY...THREAT FOR DAMAGING WIND AND LARGE HAIL WILL PERSIST
THROUGH MID EVENING ACROSS REMAINING PORTION OF WW 459 WITH GREATEST
THREAT EXPECTED TO PERSIST OVER SRN IA NEXT FEW HOURS.

DISCUSSION...EARLY THIS EVENING A COLD FRONT EXTENDS FROM NCNTRL IA
SWWD TO NERN KS. AN OUTFLOW BOUNDARY WAS LOCATED OVER SRN IA
EXTENDING INTO SWRN IA WHERE IT INTERSECTS THE CONVECTIVELY ENHANCED
COLD FRONT. STORMS ARE MOST NUMEROUS ALONG IA PORTION OF THE FRONT
AND JUST NORTH OF THE CONVECTIVE OUTFLOW BOUNDARY. OBJECTIVE
ANALYSIS SHOWS THE WARM SECTOR REMAINS STRONGLY UNSTABLE WITH AN
AXIS OF 3000-3500 J/KG MLCAPE OVER SRN IA AND NRN MO. STORMS ARE
EXPECTED TO DEVELOP ESEWD THROUGH THE EVENING...EVENTUALLY SPREADING
INTO EXTREME NRN MO AND WCNTRL IL. DES MOINES VWP INDICATE SUPERCELL
WIND PROFILES WITH 35-40 KT EFFECTIVE BULK SHEAR JUST NORTH OF THE
OUTFLOW BOUNDARY. TENDENCY WILL REMAIN FOR MOST STORMS TO BE
UNDERCUT BY THIS SWD ADVANCING BOUNDARY WHICH ALONG WITH ONSET OF
NOCTURNAL COOLING SHOULD LIMIT ANY TORNADO THREAT GIVEN ITS STABLE
CHARACTERISTICS. PRIMARY THREAT WILL CONTINUE TO BE DAMAGING WIND
AND LARGE HAIL. 

TENDENCY HAS BEEN FOR STORMS TO DIMINISH WITH SWRN EXTENT INTO NERN
KS WHERE THE 00Z RAOB FROM TOPEKA INDICATES AN INVERSION NEAR 850
MB...AND SUGGESTS CONVECTIVE INHIBITION WILL UNDERGO A SUBSTANTIAL
INCREASE WITH ONSET OF NOCTURNAL COOLING. THIS POTENTIALLY HOSTILE
THERMODYNAMIC ENVIRONMENT AND EXPECTED LIMITED INCREASE IN THE
NOCTURNAL LLJ LOWER CONFIDENCE IN REDEVELOPMENT IN THIS AREA.

..DIAL.. 07/29/2015

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

ATTN...WFO...DVN...DMX...EAX...OAX...TOP...

LAT...LON   39349709 40769573 41839439 42039299 41639131 40849109
            40319278 39589468 38919686 39349709 

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SPC MD 1565

MD 1565 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF THE TX PANHANDLE NEWD THROUGH CNTRL KS INTO NERN KS AND FAR NWRN MO

MD 1565 Image


MESOSCALE DISCUSSION 1565
NWS STORM PREDICTION CENTER NORMAN OK
0450 PM CDT TUE JUL 28 2015

AREAS AFFECTED...PORTIONS OF THE TX PANHANDLE NEWD THROUGH CNTRL KS
INTO NERN KS AND FAR NWRN MO

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 282150Z - 290015Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THUNDERSTORM DEVELOPMENT IS FORECAST TO OCCUR WITHIN THE
NEXT FEW HOURS...AND A FEW SEVERE THUNDERSTORMS WILL BE POSSIBLE
INTO THE EVENING HOURS. CONVECTIVE TRENDS WILL BE MONITORED ACROSS
THE AREA.

DISCUSSION...A SLOW-MOVING/STALLING SFC BOUNDARY IS ANALYZED FROM
NEAR BEATRICE NEB TO E OF DODGE CITY KS TO AMARILLO TX...AND
INSTABILITY IS BECOMING STRONG ALONG AND ON THE WARM SIDE /E AND S
SIDE/ OF THE BAROCLINIC ZONE. MLCAPE VALUES ARE ESTIMATED TO BE
BETWEEN 3000 AND 4000 J/KG WITH LITTLE INHIBITION REMAINING. VISIBLE
SATELLITE IMAGERY INDICATES PATCHY...BOUNDARY-LAYER-BASED CUMULUS
FIELDS BECOMING INCREASINGLY AGITATED INVOF THE BOUNDARY AS THE PBL
HAS DEEPENED WITH SFC TEMPS HAVING REACHED 95-103F ON THE WARM SIDE
OF THE BOUNDARY.

PRESENT INDICATIONS ARE THAT ISOLATED TO SCATTERED THUNDERSTORMS
WILL DEVELOP DURING THE NEXT FEW HOURS AND BECOME INTENSE OWING TO
THE STRONG INSTABILITY. STEEP LOW-LEVEL LAPSE RATES ASSOCIATED WITH
DCAPE AROUND 1200-1600 J/KG WILL CONTRIBUTE TO STRONG DOWNDRAFTS
WITH A FEW SVR WIND GUSTS POSSIBLE. THE LARGE DEGREE OF BUOYANCY MAY
ALSO SUPPORT SOME SVR HAIL POTENTIAL. FURTHERMORE...THE STALLING
NATURE OF THE BOUNDARY MAY PROVIDE SOME FRONTAL-ZONE RESIDENCE TIME
FOR TSTMS TO INTERACT WITH RELATED BOUNDARY-ENHANCED VERTICAL
VORTICITY TO BE STRETCHED FOR A NON-ZERO -- ALBEIT LOW -- TORNADO
POTENTIAL.

HOWEVER...EFFECTIVE BULK SHEAR MAGNITUDES OVER 25 KT ARE GENERALLY
DISPLACED TO THE COOL SIDE OF THE BOUNDARY WHERE SVR POTENTIAL WILL
BE VERY LIMITED IN THE HIGH-MLCINH ENVIRONMENT. AS SUCH...TSTMS MAY
STRUGGLE TO ORGANIZE ACROSS THE REGION...LIMITING THE OVERALL
COVERAGE OF SVR POTENTIAL...LIKELY PRECLUDING WW ISSUANCE.
REGARDLESS...TRENDS WILL CONTINUE TO BE MONITORED -- PARTICULARLY IN
NERN KS TO FAR NWRN MO THAT WILL BE IN CLOSER PROXIMITY TO THE TAIL
END OF A GLANCING MID-LEVEL PERTURBATION LOCALLY ENHANCING
ISENTROPIC ASCENT IN THESE AREAS. SLIGHTLY STRONGER DEEP SHEAR
RELATED TO THIS FEATURE MAY ENCOURAGE AN EVOLUTION TO MORE ORGANIZED
MULTICELL CONVECTIVE CLUSTERS WITH A SOMEWHAT GREATER SVR RISK.

..COHEN/HART.. 07/28/2015

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

ATTN...WFO...EAX...TOP...ICT...OUN...GID...DDC...AMA...

LAT...LON   39799726 39949478 39619450 39349500 38809632 38139734
            36130013 35120209 35280259 35660240 38089959 39799726 

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SPC MD 1552

MD 1552 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR EXTREME NORTHEAST WY…EXTREME SOUTHEAST MT…AND WESTERN SD

MD 1552 Image


MESOSCALE DISCUSSION 1552
NWS STORM PREDICTION CENTER NORMAN OK
0350 PM CDT MON JUL 27 2015

AREAS AFFECTED...EXTREME NORTHEAST WY...EXTREME SOUTHEAST MT...AND
WESTERN SD

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 272050Z - 272215Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...SEVERE WEATHER THREAT IS EXPECTED TO INCREASE ACROSS
EXTREME NORTHEAST WY AND EXTREME SOUTHEAST MT INTO WESTERN SD THIS
AFTERNOON INTO THE EVENING...WITH A SEVERE WEATHER WATCH ISSUANCE TO
BE COORDINATED SOON FOR THIS REGION AND LOCATIONS FARTHER NORTH AS
DISCUSSED IN MCD 1551.

DISCUSSION...TRENDS IN LIGHTNING DATA...GOES-R CLOUD-TOP COOLING
PRODUCT AND RADAR IMAGERY INDICATED A RELATIVELY RAPID INCREASE IN
TSTM INTENSITIES WITH STORMS TRACKING TO THE NNE ACROSS FAR NE WY
AND FAR WRN SD IN VICINITY OF A COLD FRONT IN FAR ERN WY AND A N-S
ORIENTED PRE-FRONTAL BOUNDARY.  THE PRESENCE OF STEEP MIDLEVEL LAPSE
RATES AND STRONG INSTABILITY NEAR AND EAST OF THESE BOUNDARIES
FAVORS SUSTAINED/STRONG UPDRAFTS...WHILE STRENGTHENING BULK SHEAR
WILL ENHANCE THE LIKELIHOOD FOR ORGANIZATION.  THE RECENT INCREASE
IN STORM INTENSITIES IS LIKELY INDICATING THE LEADING EXTENT OF
STRONG FORCING FOR ASCENT SPREADING ACROSS THE NORTHERN PLAINS THIS
AFTERNOON WITH THE APPROACH OF THE UPSTREAM...PROGRESSIVE SHORTWAVE
TROUGH.

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

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

ATTN...WFO...BIS...LBF...UNR...CYS...BYZ...

LAT...LON   44350564 45970428 46010238 44710180 43830196 42970203
            43020385 43530438 43590516 44350564 

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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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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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