US Final Extended Weather thru Apr 28

Overview And Preferences...

There Is Still Decent Consensus Among Guidance Regarding The
Canada/Conus Mean Trough From Wed Into Thu.

In Recent Days Guidance Has Been Pointing Toward Late This Week For A Decline In Fcst Confidence As Reflected By Spread In Handling Of Ern Pac/Wrn Noam Flow. Latest Guidance Seems To Be Showing Somewhat Improved Clustering With The Idea Of Some E-Cntrl Pac Energy Ejecting Into/Through The Ridge Off The West Coast Followed By A Moderate Rebuilding Of The Ridge Next Weekend... But Uncertainty With Exact Details Of High Latitude Flow Reaching The Nern Pac Around Fri Still Complicates The Fcst.

Teleconnections Relative To The Negative Hgt Anomaly Center Fcst
To Be Over Nrn Canada Appear To Support The Guidance Trend Toward Lower Amplitude Mean Flow Over The Conus... While The Mean Ridge Off The West Coast Offers Potential For Any Energy Reaching Wrn Noam To Amplify Into A Positively Tilted Shrtwv By Late In The Fcst.

Prefer A 50-50 Blend Of The Compatible 00 Utc Ecmwf/Ecmwf Ensemble Mean Wed. Amid Rapidly Growing Uncertainty...Leaned On Just The 00 Utc Ecmwf Ensemble Mean Thu Through Next Weekend That Of All Ensemble Means Offers The Closest To A Compromise Solution. Recent Guidance Spread And Run To Run Changes Suggest A Period Of Lower Than Desired Continuity With Some Aspects Of The Fcst.

...Guidance Evaluation...

The Wpc 50-50 00 Utc Ecmwf/Ecmwf Ensemble Mean Blend Wed Tends To Maintain Some Of The More Predictable Specifics But Otherwise Acts To Average Out Ongoing Detail Diffs With The Wave Fcst To Be Off The Nern Coast As Of Early Wed...A Wavy Front Crossing The East Wed Into Thu...And Weak Frontal System/ Anchoring Sfc Low Reaching The Grtlks Wed-Thu. Consult The Wpc Model Diagnostics Discussion Pmdhmd For Updated Preferences Of These Systems.

Forecast Spread Over The Conus And Vicinity Increases Rapidly

This Originates From Diffs In How Much Energy Ejecting From A Broad E-Cntrl Pac Circ Goes Through The Mean Ridge Off The West Coast At The Same Time Diffs Exist With Flow That Reaches The
Nern Pac Near The Sern Ak Coast. The End Result In The 00 Utc
Ecmwf Ensemble Mean Is Low Amplitude Flow Aloft Which Is A
Plausible Fcst Given The Nrn Canada Closed Low... With Rather Weak Sfc Evolution. Meanwhile The Mean Ridge Off The West
Coast...Expected To Rebuild Somewhat After Passage Of The Ejecting E-Cntrl Pac Energy...May Support Modest Conus Amplification.

Trends Toward At Least A Brief Flattening Of The Ern Pac Ridge Has
Led To A Slightly Faster Adjustment With The Closed Low Fcst To
Track Over/Near The Srn Ca Border During The First Half Of The
Period. But As Has Tended To Be The Case Recently...Latest Gfs
Runs Are On The Faster Side Of The Spread While Water Vapor
Imagery Still Seems To Instead Favor A Slower Track More In Line
With The 00 Utc Ecmwf/Ecmwf Ensembles.

...Sensible Weather Highlights...

Cold Front Crossing The Ern States Wed Into Thu Will Be
Accompanied By A Band Of Rnfl With Some Locally Mdt-Hvy Amts Psbl. Behind This Front A Weak System Will Spread Mostly Lgt Pcpn
Across The Nrn Tier/Grtlks.

By Next Weekend Broadening Gulf Inflow Will Increase Rnfl Potential Over Portions Of The Cntrl-Ern Conus... With Energy Originally Assoc With The Srn Stream Ern Pac Closed Low Psbly Enhancing Activity At Some Locations. Current Indications Are That Highest Totals Would Be S Of 35-40n Latitude.

At The Same Time An Increased Pacific Component Of Flow Aloft
Should Bring Some Mstr Into The Nwrn Conus And Then The Nrn Plains With Lgt-Mdt Amts. The Expected Trend Toward Flatter Mean Flow Aloft Should Lead To A Moderation Of The Chilly Temps Fcst Over The Cntrl-Ern States Early In The Period. Wrn Locations Should
See Near To Above Normal Temps.

WTVY-TV 285 N Foster Street Dothan, AL 36303 334-792-3195
Copyright © 2002-2016 - Designed by Gray Digital Media - Powered by Clickability 204017381 -
Gray Television, Inc.