Severe Weather Threat thru Jul 13

Sun Jul 6 Convective Outlook
Storm Prediction Center Norman Ok
Slgt Risk Svr Tstms for Upper Ms Valley And Midwest...

Severe Thunderstorms Capable Of Damaging Wind Gusts...Large Hail And Perhaps A Tornado Will Be Possible Across Parts Of The Midwest This Afternoon Into Tonight.

Srn Mn...Wi...Ia...Nrn Il...

Visible Satellite Shows Low Clouds Have Been Slow To Erode From Nern Ia Into Wi Which Has Limited Heating And Maintained A Capped Air Mass. However...Heating In The Vicinity Of The Cold Front From Nwrn Ia Into Sern Mn And Nwrn Wi Is Gradually Eroding Cin. Also...
Substantial Moisture And Instability Remain Over The Region. While The Potential For More Widespread Severe Coverage Is Uncertain...At Least Isolated Severe Hail And Wind Still Appear Likely From Late Afternoon Through Evening...Centered On Ia...Nrn Il And Srn Wi.

This Update Includes A Slight Wwd Shift To The Sig Hail Area Toward The Ia Portion Of The Cold Front Where Stronger Heating

Prev Discussion...

Strong Upper Short Wave Trough Over Far Nwrn Ontario And Nrn Mn Is
Expected To Continue Moving Esewd As A Band Of Strong Wnwly
Mid-Upper Level Winds Progress From The Pacific Nw Toward The Upper Ms Valley And Great Lakes. Water Vapor Imagery Also Depicts A More Subtle Perturbation In The Wnwly Flow Entering Wrn Nd And Nrn Sd...And This Is Expected To Move Toward The Upper Ms Valley Later This Afternoon And Evening.

A Surface Cold Front From Nrn/Wrn Mn Swwd Into Central Neb Is Forecast To Move Ewd/Sewd Through The Period...Reaching A Wrn Upper Mi/Central Ia/Srn Neb Line Late This Afternoon...Continuing Into
Lower Mi/Nrn Il/Nrn Mo/Nrn Ks By The End Of The Period.

Upper Ms Valley/Wrn Great Lakes...

Most Model Guidance Is Indicating That Storms Will Develop Along The Cold Front From Nern Mn...Wrn Upper Mi...Nwrn Wi...Sern Mn...Nrn Ia By Mid Afternoon...With Activity Spreading Ewd/Sewd With Time. Wind Profiles Exhibit Veering With Height As Swly Low Level Flow Becomes Wnwly In The Mid Levels With Resultant Effective Shear Of 30-40 Kt.

This Will Enhance Storm Organization With Several Bands/Clusters Of
Strong/Severe Storms Expected To Spread Across The Region Through The Evening Hours. The Slight Risk Area Has Been Expanded Nwd/Ewd Across Nrn Wi Into Upper Mi And Ewd Into Parts Of Lower Mi Consistent With Mesoscale And Most Convection-Allowing Model Guidance. Large Hail And Damaging Wing Gusts Are Expected To Be The Primary Severe Hazards But An Isolated Tornado Or Two May Also Occur.

Lower Mo Valley...

Farther To The W Across Sern Neb/Nern Ks/Nwrn Mo...Isolated Afternoon/Evening Storms May Evolve Into A Swd-Moving Complex With A Risk For Locally Damaging Winds And Marginally Severe Hail.

For This Area...The Cap Is Expected To Be Stronger And Greater Uncertainty Exists In Expected Storm Coverage With More Variability Among Model Guidance. 5% Hail/Wind Probabilities Will Be Maintained...But Area Will Be Monitored For A Possible Increase In Severe Potential.

Nern Mt Into Nd...

Residual Low Level Moisture Remains From The Srn Parts Of The
Prairie Provinces Into Mt And Nd Where Surface Dew Points Are
Generally In The 50s. This Will Contribute To Modest Instability With Mlcape Of 500-1000 J/Kg This Afternoon Into Tonight. Model Guidance Indicates A Low Amplitude Short Wave Trough Entering Srn Bc Will Progress Into Srn Parts Of Alberta And Saskatchewan Later
Today/Tonight With A Few Strong Storms Spreading Esewd Across Parts Of Nrn Mt Into Nd. Stronger Cells Will Be Capable Of Producing
Gusty Winds And Hail.


Mon Jul 7 Convective Outlook
Storm Prediction Center Norman Ok
Slgt Risk Svr Tstms for Mid Mo & Upper Ms Valley E to Oh Valley & W New England...

Pockets Of Severe Hail And Wind Are Expected From The Central Plains And Upper Mississippi Valley Eastward Across The Ohio Valley And Into New York And Western New England. The Most Concentrated Area Of Severe Weather Is Expected Across Sern Nebraska...Southern Iowa...Northeastern Kansas...And Northern Missouri.

A Broad Area Of Cyclonic Flow Aloft Will Extend From The Nrn Plains
Ewd Across The Great Lakes And Nern States...With Primary Shortwave Developing Sewd Across Sd...Mn...Ia And Neb By 00z. This Shortwave Will Reinforce The Surface Front With Forcing For Ascent Increasing From Srn Mn Into Wi During The Evening. Srn Portions Of This Front Will Sink Swd To Around The Neb/Ks Border By 00z...With Strong Instability Developing From This Boundary Sewd Across Mo And Into The Oh Valley Where Upper 60s To Near 70 F Dewpoints Will Remain.

Farther E...A Wswly Flow Regime Will Bring Moist And Unstable Air
Newd Across The Oh Valley And Into The Lower Great Lakes...With A
Low-Amplitude Leading Shortwave Trough Aiding The Development Of Storms With A Wind Threat From Ern Oh/Pa Into Ny And Wrn New England During The Day.

Neb...Ks...Srn Ia...Mo...

A Front Will Stall Near The Srn Neb/Nrn Ks Border Into Nwrn Mo...With Very Strong Heating And Steep Lapse Rates Developing Across Ks... And An Axis Of Higher Dewpoints Sheltered Along The Boundary.

Development Should Be Muted For Much Of The Day...But By Late Afternoon Or Early Evening...Height Falls Will Increase On The Srn Periphery Of The Nrn Plains Trough...And The Low Level Jet Will Increase Out Of The Sw.

Given The Well-Mixed Air Mass To The Sw...Capping Should Be Breached In An Elevated Sense Along The Front...With An Mcs Rapidly Developing Across Sern Neb And Nern Ks...Then Developing Sewd Across Srn Ia And Nrn Mo During The Evening. Damaging Winds And Large Hail Will Both Be Likely. Later Outlooks May Be Able To Delineate A Corridor Of Significant Wind Damage Potential As Predictability Increases.

Srn Mn...Wrn Wi..Nrn Ia...

Lift Will Increase As A Relatively Intense Shortwave Trough Moves
Into The Upper Ms Valley During The Afternoon. Cool Temperatures
Aloft Should Compensate For The Lower-Thetae Air Mass That Will Be
In Place Ahead Of The Cold Front...With Severe Hail Possible. The
Long Hodographs May Favor Splitting Cells With Any Tornado Threat
Likely Brief And Weak With Such Marginal Srh.

Oh Valley Newd Into Ny And Wrn New England...

Sufficient Instability For Strong To Severe Wind Will Develop Over A
Large Area From The Oh Valley Newd. Ongoing Rain/Storms Are Expected Across Oh/Lake Erie Early In Association With The Leading Shortwave Trough. This Feature Will Continue Newd With An Increase In Storm Intensity And Coverage By Afternoon From Pa Into Ny And Vt/Nh. Strengthening Mainly Unidirectional Winds Suggest A Few Small Bows Capable Of Damaging Winds Will Exist. However...The More Rightward-Moving Cells May Gain Supercell Characteristics As The Move Off The Hodograph...With An Increased Threat Of Large Hail.

Srn Az...

Strong Heating Is Expected Over Much Of Az Where Weak Instability
Will Develop Along With Large Inverted-V Profiles In The Boundary
Layer. Storms Will Form Over Across Much Of Sern Az...With Weak Ely
Mid-Level Winds Perhaps Helping A Few Storms To Propagate With
Isolated Strong Or Severe Wind Gusts By Late Afternoon.


Tue Jul 8 Convective Outlook
Storm Prediction Center Norman Ok
Slgt Risk Svr Tstms for Ozarks/Oh River Valley and Tn River Valley...

Severe Thunderstorms Capable Of Damaging Winds And Hail Will Be
Possible Tuesday Especially Across Portions Of The Ozarks...Ohio
Valley...And Tennessee Valley.

Ozarks To Oh/Tn River Valleys And Northeast States...

Current Thinking Is That An Mcs Will Be Ongoing Across The Middle Ms River Valley/Midwest Tuesday Morning. Particularly On The
Southern/Eastern Fringes Of This Early Day Mcs.

Surface-Based Storm Development/Maturation Is Expected Tuesday Afternoon Across Much Of The Oh Valley And Possibly The Ozarks Near/Ahead Of A Southeastward-Moving Cold Front. Moderate Buoyancy With Upwards Of 2000-2500 J/Kg Of Mlcape Is Expected Within The Warm Sector.

Although The Strongest Deep-Layer Wind Field Will Reside To The
North Of The Frontal Zone...30-40 Kt Of Effective Shear Will Support
Some Supercells With A More Prevalent Convective Mode Of Sustained Multicells/Line Segments With Embedded Bows. Damaging Winds And Severe Hail Will Be Possible.

Farther Northeast...At Least Isolated Severe Thunderstorms Capable
Of Damaging Winds/Hail Will Be Possible Across Portions Of The
Northeast States And Possibly Southern New England Tuesday

South-Central Plains...

A Surface Front Will Settle Southward Across The South-Central
Plains On Tuesday. Upper-Level Forcing Is Not Readily Apparent To
The Southwest Of Stronger Cyclonic Westerlies...But Sufficient
Convergence Near The Front...And A Hot/Unstable Air Mass To Its
South...May Allow For The Development Of Some Stronger Pulse-Type
Storms Capable Of Downbursts/Some Hail Tuesday Afternoon/Early


While Guidance Variability Exists...And A Particularly Organized Severe Risk Is Not Currently Anticipated...A Sufficient Amount Of Moisture/Buoyancy And The Persistence Of East-Southeasterly Mid-Level Winds Could Contribute To Strong Downburst Potential Tuesday Afternoon/Evening.


Jul 9-13 Convective Outlook
Storm Prediction Center Norman Ok

Guidance Continues To Favor Prevalent Ridging Over The Western / Southern Conus With Stronger Westerlies Relegated To Canada And The Great Lakes/Northeast States This Week.

As A Front Continues Slowly South On Day 4/Wednesday...Isolated Mainly Pulse-Type Or Multicellular Storms May Pose A Locally Damaging Wind Risk Across The Tn Valley/Southern Appalachians

For Days 5/6 Thursday/Friday...Even While The Stronger Westerlies / Upper-Level Forcing Will Remain North Of The International Border...At Least Some Severe Risk Could Materialize Across Parts Of The Dakotas/Upper Midwest As Moisture Steadily Increases Across The Region.

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