US Extended Forecast thru Apr 6

Extended Forecast Discussion
Weather Prediction Center College Park Md
1134 Am Edt Sun Mar 30 2014
Valid 12z Wed Apr 02 2014 - 12z Sun Apr 06 2014

Overview...

Split-Flow Pacific-Dominated Upper Pattern Will Bring A Whole Host
Of Weather To The Conus Over The Next Week... With Wintry
Conditions Across The North And Summertime Heat Across Texas Into The Gulf Coast Region.

The Battle Zone In Between Will Aid In The Development Of A Healthy System Moving Out Of The Tx/Ok Panhandle Toward The Great Lakes And Off The East Coast By Next Sun/D7.

The North-Central And Northeast Pacific Still Exhibits A Fair Amount
Of Spread In The Details Of The Forecast... But Keeps A Series Of
Weaker Systems Moving Through The Region... With Occasionally
Breezy To Windy Offshore Flow Conditions.

Model Preferences/Uncertainty Assessment...

Bowing To Climatology... The Models/Ensembles Have Trended Toward An Overall Slower And More Amplified Solution As The Western Energy Moves Through Co Thu/D4 And Into The Great Lakes By Sat/D6.

April Is A Favored Month For Mid-Level Closed And Cutoff Lows And
This One... Though Progressive And Not Separated From The Mean
Flow... Fits Well In The Climatological "Cutoff Freeway" From Az
To Ia To Mi.

Canadian/Gfs/Gefs Runs Have Been Less Developed With The Upper Feature As It Streams Northeastward Through The Central Plains While The Ecmwf/Ecens Mean And Now The Ukmet Have Latched Onto A Stronger System... Which Fits The Ongoing Wpc Preference For A Slower And More Amplified Solution.

Used Their Good Agreement As The Base For The Forecast Wed-Fri/D3-5.

Gfs/Ecmwf Differences Aloft And At The Sfc Result In Very Real Qpf Differences Over The Oh/Tn Valley Into The Southeast.

Ecmwf Ensembles And Operational Run Have Been Hinting At Separate Northern And Southern Maxima Roughly Along 40n And
Then 30n Rather Than One Amorphous Qpf Blob In The Middle Per The Gfs/Gefs Mean.

As The System Moves Toward The Coast... Sfc Waves Along The Stationary/Warm Front Along/East Of The Mid-Atlantic Should Keep The Area Wedged In The Cool Ne Flow.

Cool Ssts... Only Around 40-45f... Synoptic Setup /Sfc High Over Se Canada/... And Climatology Favor Keeping The Front Farther South East Of The Appalachians.

Main Sfc Low Should Move Into Se Ontario Sat/D6 While Focus Shifts To Triple Point Or Developing Sfc Wave Along The Front As The New Main Sfc Low.

Resultant Trowal Feature Will Keep Precip Focus Over The Northeast Into Sun/D7.

Upstream Flow Over The Pac Nw Will Be Tied To Farther Upstream
Evolution Over The North-Central Pacific Near Alaska.

For Wa/Or/Ca... Trend Has Been Toward The Ecmwf-Led Idea Of Trough Splitting By Late In The Week With Mid-Level Energy Pushing Through Az And Northern Mexico As The Sfc Boundary Dissipates.

Gfs/Gefs Members Again Quicker And Weaker Than The Ecmwf/Ecens Members But Again Favored The Slower Solution
Near The Ecens Mean /In Between The 00z Gefs And 00z Ecmwf/ With A Medium-High Likelihood That The Trend Will Be Slower In Successive Runs As The Pacific Appears To Be Trending Toward More Meridional /Rather Than Zonal/ Flow By Next Weekend.

Incorporated A Modest Weighting Of The Ecmwf For Some Details.

Sensible Weather Highlights...

Main Sfc System In The Central Conus Will Be The Focus Of
Convection And Possibly Severe Weather Over Ok/Ar Thu/D4 Per
Spc... With Warm Advection/Overrunning Precip Along The Warm Front
Over The Central Mi River Valley.

Another Round Of Winter Weather Is Likely To The Nw Of The Sfc Low Over The Mid-Missouri Valley Northeastward Into The Upper Midwest And Western Great Lakes.

Ahead Of The Cold Front... Temperatures Could Soar Into The Upper
90s Over S Texas And Well Into The 70s And Low 80s Through The
Southeast And Into Nc.

Big Spread In Sfc Temps In The Ensembles Over The Mid-Atlantic And Also Ahead Of The Sfc Low And Warm Front In The Midwest... The Former Due To The Lowest Level Sfc Flow And The Latter Due To Overall Timing/Placement Differences.

The Western States Will See A Steady Stream Of Qpf Events... All
Generally On The Light Side... With Most Of The Focus To The North
Over British Columbia. Temperatures Should Be Within Several
Degrees Of Normal As The Larger Departures Will Be East Of The
Rockies.


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