Winter Weather Discussion - Jan/Feb 2011

[Snowman]

Actually it is closer than that. March is when we see at least one a year, on average.

http://www.srh.noaa.gov/oun/?n=torna...-monthlyannual

Jan: 0.3
Feb: 0.8
Mar: 4.1
Apr: 10.6
May: 20.1
Jun: 8.1
Jul: 1.8
Aug: 1.4
Sep: 2.0
Oct: 2.1
Nov: 1.4
Dec: 0.4

I did not mean to imply we did not any before that time, just the most frequent time we get tornadoes does not start until April.

[venture]

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0347 AM CST SUN FEB 20 2011

VALID 231200Z - 281200Z

...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.

..JEWELL.. 02/20/2011