US Extended Forecast Updated thru Oct 12

...Significant System Possible For The Interior West Thu-Fri...


Upper Pattern Should Favor Ridging In The Nw And Ne Pacific With
Downstream Troughing... Potentially Fairly Deep In The -4 Std Dev
Range... In The Western Conus. In The East... The Forecast Is Less
Certain Especially Early In The Period As An Upper Low Exits The
Northeast But Lingering Troughing Holds Offshore The East Coast.

...Model Evaluation/Preferences...

...In The East...

The Models Continue To Struggle With How The Upper Low Exits The
Great Lakes/Northeast. There Is Little Continuity In The Various
Deterministic Runs And Even The Ensembles Have Wavered Between A Slower/Deeper/Closed Solution Vs A Quicker/Weakening Upper Feature That Gets Picked Up By The Northern Stream In Southern Canada. The 00z Ecmwf/Ukmet Were Quickest With The Upper Low And The 00z Gfs/Canadian Were Slowest While The Gefs Ensembles Favored A Slower Solution But The Ecmwf Narrowly Favored A Somewhat Quicker /Though Washed Out/ Solution.

The 06z Gfs Offered A Somewhat Middle Ground Solution About 1/3 Of The Way Between The 00z Gfs/Canadian And Ecmwf/Ukmet... Along The Lines Of The Ec Mean. Though Confidence Is Low... In Fact... Normalized Spread In The Ecmwf Members At Just 36hrs Was Higher Than Has Been Seem In Many Months... Preferred A Forecast A Bit Quicker Than The 06z Gfs.

This Should Take The Upper/Sfc Low Toward Nova Scotia By Wed/D4
Instead Of Lingering It Over Se Ontario/S Quebec.

Later In The Week... The 00z Ecmwf Develops A Sfc Low Just Se Of The Frontal Boundary Offshore But Tracks It Northward Toward Se New England But This Is On The Far Nw Side Of The Ensemble Spread /In Similar Fashion To What It Forecast In The Same Area About 10 Days Ago Verifying 30 Sept... Which Was Too Deep And Too Far Nw/. Nevertheless... Some Ensemble Members Are As Deep/Nw As The Ecmwf So It Should Be Watched.

...In The West...

Another Significant Trough Is Forecast To Swing Through The
Interior West Mid-Late Week Next Week... Swinging A Likely Closed
Upper Low Through The Central Rockies And Then Onto The Northern Plains.

The Models/Ensemble Have Shown Better Clustering With This
Feature Over The Past Few 00z-12z Cycles... With Some Typical
Timing/Placement Differences.

The 00z Ecmwf/Ecens Mean And Even The 00z Gfs Offer A Reasonable Solution As Sfc Cyclogenesis Ensues Near Ne/Wy/Sd.

06z Gfs Seemed To Far South With The Upper/Sfc Low Compared To The Good Agreement Farther North.

Ridging To The East Should Help Guide The System Northeastward
Rather Than Eastward.

...Sensible Weather Highlights...

Wrap Around Showers Should Linger In The Northeast Until The
Upper/Sfc Low Pull Far Enough Away Wed/D4 Or So.

Should The Front Continue To Push Off The Se Coast As Advertised... Precip Should Remain Just Offshore As Well But Linger Over Florida.

Confidence Remains On The Low Side.

In The West... The Deep Trough Will Bring A Much Colder Airmass To The Region Behind It... With A 10-20 Degree Drop In Temperatures.

Heavy Precip... Especially Over The Terrain... Is Possible With Windy Conditions Area-Wide. Snow Levels Should Fall Behind The Front With Modest Accumulations Possible... Again Favored In The Higher Terrain.

Severe Wx Potential Farther East Is /Too Low/ Per The Latest D4-8 Spc Discussion But The Setup Is Worth Watching.

Closed Lows Often Misbehave.

WTVY-TV 285 N Foster Street Dothan, AL 36303 334-792-3195
Copyright © 2002-2016 - Designed by Gray Digital Media - Powered by Clickability 226609531 -
Gray Television, Inc.