US Final Extended Forecast thru Jun 1

...Pattern Overview And Preferences...

Guidance Shows Reasonable Larger Scale Agreement...With An
Amplified Mean Trough Covering The Wrn States And A Strengthening
Ridge Spread Over The East.

However There Is Continued Uncertainty For Some Details Within The Mean Trough As Well As For The Amplitude/Orientation Of Ern Canada/Nern Conus Flow Aloft Through Late Next Week.

Deterministic Model Runs Still Display Enough Scatter With Various Features To Recommend Emphasizing The Ensemble Means Through The Medium Range Period. Prefer A 60/20/20 Blend Of 00 Utc Ecmwf/Gefs/Naefs Ensemble Means Days 3-7 Tue-Sat...Leaning On The Ecmwf Mean That Maintains Better Ridge Integrity.

...Guidance Evaluation/Uncertainty Evaluation...

The Majority Of Models/Ensembles Expect Leading Shrtwv Energy To
Reach The West By Tue And Later Work Into The Plains While
Upstream Energy Flowing Into The Northwest Catches Up To The
Leading Energy. The Best Solution Clustering Has Energy
Consolidating Into A Closed System Aloft Over/Near The Nrn Plains
By Day 6 Fri.

Recent Ecmwf Runs Lean On The Slower/More Amplified Side Of
Guidance With The Leading Shrtwv Reaching The High Plains By Thu. Gfs/Gefs Means Remain On The Faster Side Of The Spread With
Upstream Energy.

Sufficient Continuity Exists To Have Above Average Confidence In The Idea Of Sfc Low Development Over/Near The Nrn Plains Around Thu-Fri.

The Uncertainty In How Multiple Pieces Of Shrtwv Energy Will Interact Leads To A Deterministic Fcst Not Much Stronger Than The Ensemble Means For The Sfc Low... And Not As Wrapped Up As The Ecmwf. Meanwhile Strength Of The Downstream Ridge And Occasionally Fast Gfs/Gefs Biases Would Favor Leaning A Little Slower Than Recent Gfs/Gefs Means Fri-Sat.

Ultimately Cannot Fully Discount Any Soln At This Time In Light Of
Typical Days 6-7 Fcst Errors. By Then Upstream...Gefs/Ecmwf/Cmc
Means Also Indicate That Pac Flow Should Begin To Amplify In
Response To Troughing S Of The Aleutians...Leading To A Sharper
Trough Near The West Coast.

Well Downstream...The Most Significant Issue Involves Amplitude Of
Ern Canada/Nern Conus Flow Aloft During The Latter Half Of The
Period And Resulting Sfc Front Posn. While Recent Ecmwf Runs Have Been Fairly Aggressive With Trough Amplitude Thus Bringing A Sfc Front Rather Far Swd...The Latest 00 Utc Run Has Backed Off Some.

On The Other Hand Gfs/Gefs Runs Keep Hgts Higher With A Farther
Nwd Frontal Zone. With Increased Compatability From 00 Utc
Guidance...A Blended Ensemble Solution Seems Reasonable.

...Sensible Weather Highlights...

The Mean Trough Aloft Over The West Will Support Unsettled Weather
Over The Wrn-Cntrl States... And Below Normal Temps Over The West
Eventually Working Swd From The Nrn Plains.

Potential Still Exists For Some Wrn Pcpn To Extend Unseasonably Far Swd.

Hgt Falls Aloft Reaching The Cntrl/Srn Plains More In Ernest After Midweek And Mid Lvl/Sfc Development Farther Nwd Late In The Week
May Support Multiple Areas Of Mdt-Hvy Rnfl Over/Near The Plains... Including Some Threat For Severe Weather.

The Warm Front Fcst To Lift Across The Nern Quadrant Of The Lower 48 Tue Onward Is Also Expected To Be Convectively Active.

After Passage Of The Warm Front Expect Persistently Above To Well Above Normal Temps Out From The Central Us To Over Much Of The East Albeit With Some Uncertainty Over The Northeast.

Finally Expect A Wet Pattern Over Srn/Ern Parts Of Fl With Moist Ely Flow On The Srn Side Of Atlc/Ern Conus Sfc High Pressure.

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