Severe Weather Threat thru Apr 5

Sat Mar 29 Convective Outlook
Storm Prediction Center Norman Ok
Slgt Risk Of Svr Tstms for parts of Sern U.S to Cntrl Fl Peninsula...

Middle Atlantic/Sern U.S...Including Fl...

Lead Srn-Stream Low-Amplitude Short-Wave Trough Will Progress Across The Gulf States Early This Morning In Response To Mid-Level
Flow/Short Wave Sharpening Upstream.

Organized Mcs Has Evolved Ahead Of This Feature With A Well-Defined Mcv Shifting East Along I-20 Corridor Over Nern La.

Current Speed/Propagation Of Squall Line Suggests Significant Convective Overturning Across The Eastern Fl Panhandle By Daybreak.

Additionally...A Corridor Of Mostly Shallow Convection Persists Within Warm Conveyor From The Nern Gom Across Coastal Carolinas Into Sern Va. This Band Of Precipitation May Be Slow To Dissipate Prior To Influence Of Strong Short-Wave Trough.

Both The Gfs/Nam Are In Reasonable Agreement Intensifying Short-Wave Trough Over The Ern Tn Valley/Sern U.S. By 30/00z As Strong Mid-Level Speed Max Rotates Across Ga Into Sc.

Decidedly Cyclonic Flow Will Overspread The Nrn/Cntrl Fl Peninsula And Despite Deepening Wly Flow Weak Ascent Should Aid Convection Across This Region.

Most Buoyant Air Mass Saturday Will Be Noted Across The Fl Peninsula Where Mucape Could Exceed 2000 J/Kg By Early Afternoon.

Forecast Sounding At 18z For Inv Exhibits Moderate Instability With
Sufficient Deep Layer Shear For Potential Supercells.

It/S Not Clear Boundary Layer Will Destabilize As Depicted By The Nam But Conditions Should Support The Potential For Large Hail With Thunderstorm Clusters Across This Region.

Farther North...Weak Lapse Rates...Partly Due To Aforementioned
Warm-Conveyor Precip...Should Limit Instability Across Ga / Carolinas / Va.

Strongest Forcing...12-Hr Mid-Level Height Falls Nearing 80m...Will Spread Into This Region By Late Afternoon As Exit Region Of Strengthening Jet Shifts East Of The Srn Appalachians.

Have Lowered Severe Probs A Bit Across Parts Of The Middle Atlantic
Due To Expected Weak Instability.

Even So...Moist Profiles And Strong Forcing Should Contribute To Bands Of Convection That May Generate Gusty Winds Within Pseudo-Adiabatic Lapse Rate Environment.

Wrn U.S...

Mid-Level Heights Should Fall Across Much Of The Wrn U.S. During The Upcoming Day1 Period As Short-Wave Trough Digs Into Ca Late In The Period.

Steepening Lapse Rates North Of Jet Core Along With Diurnal Heating Are Expected To Contribute To Sufficient Instability For Sct Showers And Isolated Thunderstorms.

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Sun Mar 30 Convective Outlook
Storm Prediction Center Norman Ok
No Svr Tstm Areas Forecast...

A Quasi-Zonal Synoptic Regime Will Persist Sunday With Another In A
Series Of Low-Amplitude Shortwave Troughs Forecast To Move From The Great Basin Sunday Morning Into The Cntrl Plains Overnight.

This Feature Will Induce Lee Cyclogenesis Over The Cntrl Plains During The Day With Trailing Pre-Frontal Trough Extending Swd Through The Cntrl/Srn High Plains.

A Cold Front Will Eventually Merge With The Lee Trough As It Moves Into The Cntrl High Plains Sunday Night.

Swrn Extension Of A Cold Front Moving Through Cntrl Canada Will Stall From The Upper Ms Valley Region Into Neb.

Cntrl Rocky Mountain Region...

Mid-Level Ascent Attending The Shortwave Trough...The Steep Lapse
Rate Environment...Along With Orographic Forcing Likely Will
Contribute To A Few High-Based Thunderstorms Over The Cntrl Rocky Mountain Region During The Afternoon.

Deep-Layer Winds Increase In Association With The Progressive Shortwave Trough In Presence Of Inverted-V Profiles.

Downward Mixing Of The Higher Momentum Air Along With Evaporative Cooling Within Convective Elements May Result In Locally Strong Thunderstorm Wind Gusts Into Early Evening.

Cntrl Plains Area...

A Strong Sly Llj Will Develop Over The Cntrl And Srn Plains East Of
The Developing Lee Cyclone.

Owing To Saturdays Gulf Cold Frontal Intrusion...There Will Not Be Sufficient Time For A Significant Return Of Low-Level Moisture...With Dewpoints Only In The 30s And 40s Expected In Warm Sector.

Nevertheless...Steep Lapse Rates /8+ C/Km/ Associated With An Ewd Advecting Eml Will Overspread Much Of This Region Resulting In At Least Weak Instability But With A Capped Boundary Layer Much Of The Day.

Deep Mixing May Contribute To High-Based Convection By Late Afternoon Over The High Plains.

This Activity Will Likely Be Shallow...But A Few Updrafts May Become
Deep/Robust Enough For Lightning Strikes.

Given The Deep Inverted-V Profiles...A Few Storms/Virga Showers Could Produce Locally Strong Wind Gusts.

Overnight...The Zone Of Mid-Level Ascent Associated With The Progressive Shortwave Trough Will Continue Interacting With The
Steep Lapse Rate Environment As It Develops Ewd Through The Cntrl
Plains...Likely Contributing To Weak Instability Along With A Few
Thunderstorms Rooted Aoa The 700 Mb Layer.

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Mon Mar 31 Convective Outlook
Storm Prediction Center Norman Ok
No Svr Tstm Areas Forecast...

A Quasi-Zonal Progressive Upper Flow Regime Will Persist Monday.

The Low Amplitude Wave That Will Move Through The Cntrl Rockies Sunday Will Have Reached The Cntrl Plains By 12z Monday.

This Feature Will Advance Enewd Into The Mid-Upper Ms Valley... Reaching The Great Lakes Later Monday Night Accompanied By A Deepening Sfc Low And Cold Front.

By The End Of This Period The Front Will Extend From The Low Over The Great Lakes Swwd Through The Oh And Tn Valleys Then Wwd
Into Nrn Tx.

Farther West Another Impulse Will Move Through Ca Into The Great
Basin Ahead Of An Upper Low That Will Approach The Oregon And Ca
Coasts Toward The End Of This Period.

Ms Valley Region And Upper Great Lakes...

The Progressive Shortwave Trough That Will Move Through The Mid Ms Valley Region Into The Great Lakes Will Remain Starved Of
Significant Low-Level Moisture.

Nevertheless...Plume Of Steep Lapse Rates And Mid-Upper Ascent Accompanying This Feature Will Likely Result In Corridor Of Weak Instability Rooted Aoa 750 Mb.

Areas Of Elevated Showers And A Few Thunderstorms Will Likely Develop In This Environment Through The Ms Valley Region And A Portion Of The Upper Great Lakes During The Day.

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Apr 1-5 Convective Outlook
Storm Prediction Center Norman Ok

Wednesday And Thursday /Day 5-6/ Significant Model Differences Have Arisen With Regard To The Shortwave Trough Expected To Affect A Portion Of The Cntrl And Srn Plains And Lower-Mid Ms Valley.

Less Run To Run Consistency Is Now Evident...Particularly With The Gfs Which Has Trended Slower And More Amplified With Each Successive Run Compared To The Ecmwf Which Has Remained A Bit More Consistent...But Also Trending Slightly Slower.

The Mref And Ecwmf Ensemble Members Also Become More Dispersive By Day 5 Which Lowers Overall Confidence In This Forecast.

By Late Day 4 Into Day 5 A Warm Front Should Lift Nwd Through The
Srn And Cntrl Plains And Lower-Mid Ms Valley Region In Association
With Lee Cyclogenesis And Strengthening Sly Llj.

This Will Allow Partially Modified Gulf Air To Advect Nwd Through The Warm Sector Beneath Steep Lapse Rates Contributing To Moderate Instability Within An Environment Of Favorable Vertical Shear.

However...With Solutions Trending Slower Concern Is That Capping Could Be A Problem With Swly Flow Advecting The Eml Plume Over The Plains...Especially Day 5 With Any Storms That May Try To Initiate On The Dryline.

It Still Appears Likely That Storms Will Develop Along The Warm
Conveyor Belt Over A Portion Of The Srn Plains And Lower-Mid Ms
Valley...Possibly Becoming Surface Based And Contributing To A
Severe Threat.

However...Timing And Placement Of A More Substantial Severe Threat Will Depend On Amplitude And Speed Of Ejecting Shortwave Trough.

Have Removed The Severe Threat Area For Now Due To Dispersive Model Solutions...But Area Will Probably Need To Be Reintroduced As Predictability Increases In Later Updates.


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