US Final Extended Weather thru May 4

...General Overview...

A Longwave Trough Digging Into The Nation's Midsection Will Be The
Main Focus Of The Medium Range Period.

The Associated Cold Front Will Quickly Push Through The Upper Midwest...Central Plains...And Central/Southern Rockies At The Start Of The Forecast Period. By Late Next Week...The Upper Trough Is Expected To Get Caught Between Strong Upper Ridging In Place Over The Labrador And An Upstream Ridge Over The Eastern Pacific/Pacific Northwest...Which Would Lead To A Cutoff System Developing Near/Over The Middle Mississippi Valley.

A Second Feature Being Monitored During The Medium Range Period Is A Piece Of Southern Stream Energy Tracking Eastward Along The Gulf Coast States The Middle Of Next Week. The Energy Has The Potential To Induce Modest Cyclogenesis In The Northeast Gulf Or Near The Southeast Coast.

...Guidance Evaluation And Preferences...

Although The Majority Of 00z Deterministic And Ensemble Guidance
Is On Board With A Large Cutoff System Near The Middle Mississippi
Valley By The End Of Next Week...There Is Certainly Some Spread
With The Exact Location.

The 00z Ecmwf/Cmc Are On The Extreme Southwestern/Slow Side Of Model Spread And Both Have A Closed Low Over The Southern Plains By Friday. The 00z/06z Gfs Runs Were More In Line With The Ensemble Mean Guidance.

Even More Concerning Than The Current Spread Is The Big Shift From Yesterday's 00z Guidance...Which Advertised A Closed Low Much Farther North Over The Upper Midwest/Upper Great Lakes. Although The General Trend Is For A Deeper/Farther Southwest Low...The Increased Uncertainty With Closed Lows Warrants A Cautious Approach. Thus...The Day 3-7 Forecast Was Based Off A Blend Of The 06z Gfs...Which Was In The Middle Of 00z Model Spread...And The 00z Ecmwf Ensemble Mean...Which Was A Bit On The Slower/Farther Southwest Edge Of Model Spread. Compared To
Continuity...This Resulted In A Bit Slower Progression Of The Cold
Front Crossing The Upper Midwest/Middle Mississippi Valley The
Middle Of Next Week.

Since The Upstream Evolution Of The Closed Low Will Have A Large
Impact On Any Low Development In The Northeast Gulf Or Along The
Southeast Coast...A Blend Of The 06z Gfs/00z Ecmwf Ensemble Mean
Was Used For This System As Well.

...Sensible Weather Highlights...

The Cold Front Will Bring A Brief Cool Down And Strong Winds To
The Great Basin And Four Corners Region Early In The Forecast
Period...But With The Upper Forcing Diving Southeastward...A Much
Bigger Drop In Temperatures Is Expected For The Central/Southern
Plains Behind The Front.

Temperatures Should Stay Well Below Average Thereafter East Of The Continental Divide...With The Exception Of Northern New England Which Will Be Closer To The Upper High.

The Strong Upper Ridge Building In Over The East Pacific/Pacific Northwest Will Bring Well Above Normal Temperatures To Much Of The Western U.S....With Triple Digits Possible Over The Desert Southwest Towards The End Of Next Week.

In Terms Of Precipitation For The Medium Range...Showers Will Be
Possible With The Cold Frontal Passage Through The West/Central
States Early Next Week... But The Bulk Of The Gulf Moisture Will
Be Caught Up With The Southern Energy Moving Toward Florida.

Towards The Middle/End Of The Next Week...Some More Organized
Rain/Thunderstorms Should Develop With The Cold Front As It Edges
Towards/Through The Middle Mississippi Valley And Is Able To Tap
Into Some Gulf Moisture.

WTVY-TV 285 N Foster Street Dothan, AL 36303 334-792-3195
Copyright © 2002-2016 - Designed by Gray Digital Media - Powered by Clickability 205036071 -
Gray Television, Inc.