Substantial Severe Threat (2/25)

There is a potential for severe weather on February 25th, 2011.

The SPC highlights the potential for active weather throughout this period.

...DISCUSSION...    AN ACTIVE PATTERN WILL PERSIST THROUGH THE PERIOD WITH THE POTENTIAL    FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK ON THU/D5.        ON WED/D4...MODEL CONSENSUS HAS A BROAD BELT OF SWLY FLOW ALOFT FROM    NRN MEXICO ACROSS THE CNTRL AND ERN U.S...AHEAD OF AN UPPER TROUGH    AXIS THAT IS FORECAST TO BE IN THE VICINITY OF THE BAJA CA/SRN CA    COAST WED MORNING. WELL AHEAD OF THIS FEATURE...LOW LEVEL MOISTURE    WILL BEGIN TO STREAM NWD OFF THE GULF OF MEXICO AS A LARGE SURFACE    HIGH OVER THE ERN STATES GRADUALLY SHIFTS OFFSHORE.        BY THU MORNING...A SURFACE LOW IS FORECAST TO BE SOMEWHERE ACROSS    NWRN TX OR CNTRL OK WITH BOUNDARY LAYER DEWPOINTS AS HIGH AS 60F UP    TO THE LOW CENTER....AND UP TO A WARM FRONT THAT WILL EXTEND EWD    ACROSS NRN OK/AR OR PERHAPS SRN MO. A SURFACE LOW AND POTENT UPPER    LEVEL JET STREAK WILL THEN CONTINUE EWD ACROSS THE LOWER MS AND INTO    THE TN/OH VALLEYS BY 00Z.        UPPER LEVEL COOLING AND A PLUME OF STEEP DEEP LAYER LAPSE RATES WILL    OVERSPREAD THE WARM SECTOR...CREATING A VERY UNSTABLE SITUATION.    ALTHOUGH THE EXACT GEOMETRY OF THE TROUGH MAY NOT BE WELL HANDLED    THIS FAR IN ADVANCE...THE CURRENT MODEL DEPICTION WOULD INDICATE THE    POTENTIAL FOR NUMEROUS SUPERCELLS ALONG THE DRYLINE/COLD    FRONT...RATHER THAN A MORE LINEAR STORM MODE. IN THIS SCENARIO...A    SUBSTANTIAL TORNADO THREAT COULD MATERIALIZE BY AFTERNOON AND    EVENING.  
   BY FRI/D6...A SEVERE THREAT OF SOME FORM MAY REMAIN ALONG THE COLD    FRONT...AS IT APPROACHES THE ERN SEABOARD...BUT TIMING OF THE FRONT    AND PREDICTABILITY BECOME TOO LOW FOR ANY ADDITIONAL SEVERE AREAS."

Below is The Weather Centre's depiction of what could happen in this situation of a 

severe weather outbreak.

Mesoscale Discussion #111

Low pressure moving east at this time. Warm front extended east of low pressure is rain/snow line. High freezing rain rates are possible as main low pressure moves east.

With freezing rain rates this high, ice glazing over surfaces appears possible/likely in the area outlined.

Further Analysis: Possible

Winter is ending.

With the snow gone and a substantial severe threat next week, it's about time to start to shut down the winter forecast pages.

I hope you liked them.

If there is anything I can fix, please let me know.

00z NAM Report

-NAM is colder

-Precip is slightly more south.

Concern of Freezing Rain change to Rain

Recent forecasts have been predicting a changeover in portions of the Great Lakes from Frzg Rain to Rain, but a run of the SREF somewhat objects to this.

Below is the SREF take on the chance for freezing rain turning into rain.

In the image around one day from now, we see a somewhat elevated risk of freezing rain turning into rain. The most risk centered around the Wisconsin/Illinois border.

3 hours later, the probability of freezing rain into rain has gone down and is much less disorganized. That leads to thinking that changeover may not be as predominant as thought.

Another 3 hours further, the risk for changeover continues but is more disorganized and now practically nonexistent.

These images are leading me to believe that the GFS model is incorrect. The SREF handled the Blizzard of 2011 well, as well as the ECMWF.

But the SREF has handled all storms in short-range quite well, so there is much reasoning behind new thinking.

Current thinking by The Weather Centre is the following:

-CHANGEOVER TO RAIN WILL NOT BE AS DOMINANT AS PREVIOUSLY THOUGHT.

-WINTRY PRECIP WILL BE MORE COMMON.