Monthly Archives: March 2015

Storm risk updated. Marginal risk of Severe thunderstorms! In March!

It’s very early to be posting about severe thunderstorms but conditions are lining up for the potential of Severe thunderstorms in Central Alberta, the main threat will be damaging winds and perhaps large hail.

There is not enough moisture for flash flooding.

Whether storm turn severe or not the dynamics for today come incredibly early. It’s at least late May before were talking about marginal Severe risk.

Another note is the potential of thunder snow as temperatures

From Focn45 http://kamala.cod.edu/Canada/latest.focn45.CWWG.html

327   
FOCN45 CWWG 311900  
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM  
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT TUESDAY MARCH  
31 2015.  
  
ALERTS IN EFFECT...SPECIAL WEATHER STATEMENT FOR NORTH-CENTRAL  
ALBERTA.  
  
THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND  
EVENING OVER PARTS OF CENTRAL ALBERTA.  
  
SYNOPTIC OVERVIEW...LONGWAVE TROUGH MOVING INLAND OVER WESTERN NORTH  
AMERICA WITH NOTABLE EMBEDDED IMPULSE MOVING THROUGH NORTHERN B.C.  
INTO NORTHERN ALBERTA. UPPER RIDGE SLIDING EASTWARDS ACROSS THE  
PRAIRIES. AT 18Z, 1000MB SURFACE LOW DEVELOPING THROUGH THE ALBERTA  
ELBOW SET TO EJECT EASTWARDS ACROSS CENTRAL PRAIRIES. TWO MAIN  
FRONTAL BOUNDARIES TODAY; FIRST IS A FRONTAL WAVE THROUGH AB/SK, WITH  
NORTH-SOUTH RUNNING COLD FRONT PUSHING INTO WESTERN ALBERTA AND  
MONTANA. THE WARM FRONT OF THIS WAVE RUNS FROM CENTRAL ALBERTA  
SOUTHEASTWARDS THROUGH SOUTH-CENTRAL SASKATCHEWAN INTO THE WESTERN  
DAKOTAS. SECOND BOUNDARY IS AN ARCTIC COLD FRONT RUNNING  
SOUTHEASTWARDS FROM NORTHERN SASKATCHEWAN THROUGH NORTHERN AND  
CENTRAL MANITOBA.  
  
DISCUSSION.  
  
PRAIRIES...A FAIRLY POTENT SPRING STORM IS ON THE WAY FOR MANY ACROSS  
THE CENTRAL PRAIRIES AS A LOW PRESSURE SYSTEM FROM THE ALBERTA ELBOW  
EJECTS EASTWARDS TODAY AND TRACKS ACROSS THE PRAIRIES OVER THE NEXT  
COUPLE DAYS.  
  
ALTHOUGH IT IS ONLY THE END OF MARCH, THE PATTERN OVER ALBERTA TODAY  
IS ONE CONDUCIVE TO THE FORMATION OF THUNDERSTORMS AND EVEN SEVERE  
THUNDERSTORMS (SHOULD MOISTURE BE PLENTIFUL ENOUGH) THAT WE CANNOT  
RULE OUT A STRAY WARNING OR TWO TODAY. THE PATTERN IS RATHER CLASSIC  
SEVERE ALBERTA--80+ KNOTS ALOFT, 50 KNOTS AT H5, SUBTLE TO STRONG  
COOLING MOVING IN, THERMAL RIDGE RIGHT OVER THE PROVINCE IN THE  
MORNING. MODIFYING WSE FOR 17/3 GIVES AN IMPRESSIVE (FOR THIS TIME OF  
YEAR) 750 J/KG. INVERTED-V PROFILES ENSUE SHOULD THIS COME TRUE, AND  
WIND GUSTS IN EXCESS OF 50 KNOTS ARE POSSIBLE. WHILE WE WON'T LIKELY  
ISSUE ANY WATCHES FOR THE REGION, IT WOULD NOT BE SURPRISING TO NEED  
TO ISSUE THE FIRST SEVERE THUNDERSTORM WARNING OF THE SEASON. AT THE  
VERY LEAST, WE HAVE INSERTED GUSTS TO 80 KM/H INTO THE PUBLIC  
FORECASTS WHERE APPROPRIATE.  
  
AFTER THE PASSAGE OF THE COLD FRONT, A FAIRLY PERSISTENT HEAVY SNOW  
WILL FALL IN WHAT SHOULD BE A CONVECTIVE BAND. THIS WILL LEAD TO THE  
POTENTIAL FOR WARNING-LEVEL SNOW, AND THE REGIONS HIT BY IT ARE NOT  
AT ALL CLEAR--IT COULD BE ANYWHERE FROM THE PEACE COUNTRY TO FORT  
MCMURRAY. SHORT-FUSE SNOWFALL WARNINGS WILL LIKELY OCCUR HERE.  
HOWEVER, FARTHER EAST, IN NORTHERN SASKATCHEWAN, THE SNOWFALL SEEMS  
TO BE MORE AGREED-UPON, AND AS A RESULT WE WILL LIKELY ISSUE SOME  
SNOWFALL WARNINGS THIS AFTERNOON.  
  
FINALLY, AFTER THE PASSAGE OF THE AFOREMENTIONED COLD FRONT, SYNOPTIC  
WINDS WILL BE STRONG AND GUSTY. PARTS OF EAST-CENTRAL ALBERTA WILL BE  
IN A RATHER TIGHT GRADIENT AND THERE WILL BE 50 KNOTS OR SO TO MIX  
DOWN. WARNINGS AREN'T BEING CONSIDERED--YET--BUT WARNING WINDS CANNOT  
BE RULED OUT TOMORROW.  
  
PRECIPITATION WITH THIS SYSTEM SHOULD MAINLY BEGIN AS RAIN TODAY AND  
THEN GRADUALLY CHANGE OVER TO SNOW TONIGHT. THIS SYSTEM WILL BE  
BOLSTERED BY AN INJECTION OF MOISTURE THIS EVENING THAT MAY RESULT IN  
SOME WEAK CONVECTIVE SHOWERS OVER SOUTHERN SASKATCHEWAN. THE SYSTEM  
WILL BRING THE THREAT OF HEAVY SNOW TO SEVERAL NORTHERN COMMUNITIES  
FROM PELICAN NARROWS IN SASKATCHEWAN ESE TO ISLAND LAKE, MANITOBA.  
ENSEMBLE SNOWFALL SOLUTIONS HAVE BEEN PUSHING 12 HR. SNOWFALL TOTALS  
TO THE 10-12 CM RANGE, HOWEVER ACTUAL TOTALS WILL DEPEND  
SIGNIFICANTLY ON THE EXACT POSITIONING OF THE RAIN-SNOW LINE AND THE  
TIMING OF THE SWITCH-OVER TO SNOW. IN ADDITION TO THE SNOWFALL,  
STRONG NORTHERLY WINDS TO 40-50 KM/H WILL LIKELY PRODUCE PERIODS OF  
POOR VISIBILITIES IN BLOWING SNOW DURING THE SNWFALL EVENT.  
NO WARNINGS HAVE BEEN ISSUED AT THIS TIME FOR THIS SYSTEM, HOWEVER WE  
WILL BE MONITORING IT CLOSELY AND SOME WINTERY WARNINGS ARE POSSIBLE,  
PARTICULARLY THROUGH THE AFOREMENTIONED REGIONS.  
  
THE SECONDARY THREAT FROM THIS SYSTEM WILL BE THE SURGE OF COOLER AIR  
ON THE BACK-SIDE OF THE SYSTEM. AFTER BASKING IN SPRINGTIME WARMTH,  
MUCH OF THE PRAIRIES WILL SEE BELOW-NORMAL TEMPERATURES RETURN BY  
WEEK'S END. TWO MAIN AREAS OF SIGNIFICANT WEATHER WILL BE WORTH  
KEEPING AN EYE ON AS THE COLD FRONT PASSES ON WEDNESDAY. THE FIRST IS  
OVER SOUTHWESTERN SASKATCHEWAN INTO SOUTHEASTERN ALBERTA WHERE THE  
COLD FRONTAL PASSAGE WILL BE MARKED BY INSTABILITY AND NOTABLE WINDS.  
AT THIS POINT, WINDS OF 40-50 KM/H SEEM QUITE LIKELY ALONGSIDE  
CONVECTIVE SHOWERS OR FLURRIES. IT'S STILL EARLY, HOWEVER THERE IS A  
SLIGHT POTENTIAL THAT WE MAY EVEN SEE SOME SNOW SQUALL ACTIVITY  
BEHIND THE COLD FRONTAL PASSAGE LATE WEDNESDAY INTO WEDNESDAY  
EVENING. THE SECOND, LESSER, AREA OF CONCERN WILL BE THROUGH THE  
MANITOBA INTERLAKE AND RED RIVER VALLEY WHERE SOME FLURRIES WILL MOVE  
THROUGH ALONGSIDE STRONG NORTHERLY WINDS.  
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Spring storm update. Warm sector thunderstorms and Warnings issued for snowfall.

The cold system continues but with a more complex set-up.

Snowfall and fog warnings have been issued for a wide swath through Central Alberta including Red Deer and areas just south of Edmonton. 10cm or more locally is expected

Due to a high level on instability Thunderstorms are expected in the warm sector of the system and thundersnow is possibly in the warning areas.

Stay tuned for further

Major Spring snow storm taking aim at central and northern Alberta!

Now that we have melted most if not all of the winter snowpack it looks like some areas including Edmonton are going to get it all back.

Models indicate between 15 and 30+cm to fall in a band from Grande Prairie to Loydminister hand as far south as Red Deer. Outside that as far south as Calgary can expect 5-15cm in some location.

Around 10cm of the total amounts should melt on contact or between the two rounds of heavier snow.

The system is already arrived and starting as rain, it will change over to snow tonight and on and of continue for the next 4 days. Heaviest snow will be on the weekend and on Tuesday. Sustained winds will be around 25km/h with gusts as high as 50km/h. Expect reduced visibility in exposed areas. The primary concern is the the wet and heavy nature of the spring snow, power outages due to ice and snow laden trees and wires should be expected with amounts as high as 30cm. Road conditions as always will be treacherous so limit you weekend activities accordingly. Plus its not like we did not get two weekends in a row in the mid teens

The ground has also thawed partly so this huge dump will likely melt into the ground and serve as fuel for the 2015 storm season. Also if temperatures make a quick rebound localized flooding may be a concern. Currently this is not the case as it may take until the following weekend to rebound.

I would expect warnings from environment Canada if models continue to hold in this direction.

Stay tuned for further details and changes as this storms severity is still uncertain