Pasting a couple relevant bids from the Prairie Arctic Storm Prediction Centre's morning statement at:
http://kamala.cod.edu/Canada/latest.focn45.CWWG.html
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From the link:
[i]SEVERE THUNDERSTORM
WATCHES IN SOUTHEAST SASKATCHEWAN LIKELY TO BE UPGRADED TO TORNADO
WATCHES LATER THIS MORNING AND EXTENDED INTO SOUTHWEST MANITOBA. [/i]
and then later in the link, this lengthy section that gives an idea to how things are setup and where the biggest risk areas are:
[i]
THE MAIN WEATHER STORY IS THE RAPID DEVELOPMENT OF THE LOW PRESSURE
SYSTEM IN EASTERN MONTANA THIS MORNING. WHILE THERE WAS UNCERTAINTY
YESTERDAY ABOUT THE PLACEMENT AND MOTION OF THE LOW, NOCTURNAL
THUNDERSTORM ACTIVITY IN THE WARM SECTOR WAS VERY QUIET, AND
SATELLITE HAS BORNE OUT THE EXTREMELY SHARP AND DIGGING TROUGH OVER
THE WEST PREDICTED BY MOST MODELS. SURFACE ANALYSIS EARLY THIS
MORNING SHOWS THE LOW PLACEMENT AS FORECAST AND IS BEARING OUT THE
EARLY STAGES OF NORTHWESTWARD MOVEMENT AND DEEPENING AS WELL. WEST
OF THE LOW, THE UPPER LEVEL JET CONTINUES TO POWER A FEW SEVERE
THUNDERSTORMS JUST SOUTH OF THE INTERNATIONAL BORDER AT CORONACH.
THIS TOO IS WELL CAPTURED BY THE HOURLY CYCLING MODELS, AND THE
THREAT WILL LIKELY PUSH INTO THE SOUTHEAST CORNER OF SASKATCHEWAN
HENCE THE SEVERE THUNDERSTORM WATCH FOR THE REMAINDER OF THE
MORNING. THESE THUNDERSTORMS ARE FORECAST TO WEAKEN WITH SUNRISE,
BUT EVEN IF THEY DO NOT, THE RAPID LIFTING OF THE WARM FRONT
NORTHWARD AND THE TILTING OF THE JET WILL CONTINUE TO SHIFT THESE
EARLY ELEVATED THUNDERSTORMS AND/OR RAIN NORTHWARD.
THUS, MANY OF THE CONDITIONS POTENTIALLY PREVENTING THE DEVELOPMENT
OF MORE SIGNIFICANT SEVERE WEATHER IN SOUTHEAST SASKATCHEWAN AND
SOUTHWEST MANITOBA ARE BEING REMOVED THIS MORNING. OVER THE MONTANA
LOW ITSELF, SKIES ARE PARTLY CLOUDLY WITH ONLY A FEW WEAK
THUNDERSHOWERS, SO IT DOES LOOK LIKE MANY AREAS WILL SEE SOME SUN
TODAY. A PLUME OF 20 DEGREE DEWPOINTS IS EXPECTED TO WRAP AROUND THE
LOW, INTERSECTING WITH THE STEEPEST MID LEVEL LAPSE RATES WITH GOOD
SURFACE CONVERGENCE AT THE WARM FRONT ABOUT THE CARLYLE AREA EARLY
THIS AFTERNOON. HODOGRAPHS HERE NOW HAVE EVEN MORE IMPRESSIVELY
VEERING PROFILES COMPARED TO YESTERDAY, STILL WITH UP TO 55 KNOTS OF
DEEP LAYER SHEAR ACCOMPANIED BY 2500 J/KG MLCAPE. THUS, THE
POTENTIAL FOR TORNADIC SUPERCELLS CONTINUES TO RISE FOR THE
AFTERNOON HOURS. ACCOMPANYING FORECAST 0-3 KM EHI VALUES HAVE NOW
RISEN TO TO 6+ AND SIGTOR NOW PEAKED OVER 4. MODELS ARE IN EXCELLENT
AGREEMENT, WITH VALUES QUICKLY FALLING OFF BELOW 0.5 IN ABOUT A 150
KM RADIUS ON ALL SIDES.
ALL THAT REMAINS IS THE CAPPING INVERSION, WHICH IS WEAKER BUT STILL
PRESENT - AGAIN WEAKEST AROUND CARLYLE WITH ONLY -20 J/KG MLCIN BY
21Z, AND RAPIDLY INCREASING TO -100 J/KG TO THENORTHEAST AND
NORTHWEST. ALSO OF NOTE ARE THE HANDFUL OF ONGOINGSEVERE
THUNDERSTORMS TO THE WEST AND THE - LIKELY ASSOCIATED -NUMEROUS
RIPPLES IN THE UPPER LEVEL LOW. A FEW MODELS TRIGGERAFTERNOON STORMS
ABOUT THESE UPPER FEATURES AND SURFACE OUTFLOW, BUTSTILL IN THE SAME
AREA. AT ANY RATE, SUPERCELL DEVELOPMENT WILL BE RAPID WHERE IT
OCCURS AND QUICKLY TRANSITION INTO A MUCH LARGERLINEAR SYSTEM
BUILDING NORTH AND EAST. THE ODD OUTLIERMODEL THAT DOES NOT DEVELOP
SURFACE BASED CONVECTION THIS AFTERNOONSTILL SWEEPS THROUGH THE AREA
WITH ELEVATED CONVECTION AS THE LOW PASSES OVER THIS EVENING. ALL
THIS WARRANTS A MODERATE TO HIGH RISK OF SEVERE THUNDERSTORMS WITH
POTENTIAL FOR TORNADOES, SIGNIFICANT LARGE HAIL, WINDS, AND RAIN IN
AREA BOUNDED BY CORONACH, BROADVIEW, AND PILOT MOUND. A SLIGHT RISK
IS WARRANTED NORTHEAST TO THE REGINA AREA AND NORTH TO YORKTON,
WHERE LIKELY MORE ELEVATED STORMS COULD STILL POSE A WIND, HAIL AND
RAIN THREAT INTO THE EVENING.
FURTHER EAST, MOST OF REMAINING WESTMAN IS ALSO IN A SLIGHT RISK
ZONE THIS AFTERNOON AS WELL. THE HIGHER HUMIDITY OVER MANITOBA LOOKS
TO MAKE RAINFALL A RISING CONCERN AS THE DAY WEARS ON, ALONG WITH
THE POTENTIAL FOR WIND AND LARGE HAIL. REGARDLESS OF DAYTIME
ACTIVITY, THIS SAME SETUP IS PROMISING FOR SEVERE ELEVATED
CONVECTION ACROSS ALL OF SOUTHERN MANITOBA TONIGHT. MUCAPES OF 1500
J/KG OR SO PERSIST THROUGH THE NIGHT, COUPLED WITH THE NOSE OF A
STRONGER SOUTHERLY 850 MB JET AT 50 KNOTS AND STRONGER STILL UPPER
LEVEL WINDS MOVING IN FROM THE SOUTHWEST.
BACK NORTHWEST OF THE LOW, MORE WIDESPREAD RAIN IS STARTING THIS
MORNING IN THE SOUTHWEST AND IS EXPECTED TO SPREAD NORTHEASTWARDS
INTO TONIGHT. WITH THE LOW ON TRACK, THERE IS GOOD AGREEMENT FOR A
SWATH OF TWO DAY 50 TO 80 MM RAINFALL TOTALS RUNNING FROM THE
CYPRESS HILLS NORTHEAST TO GRAND RAPIDS, AND THUS THE RAINFALL
WARNING HAS BEEN ISSUED. ADDED AMOUNTS IN THUNDERSTORMS COULD BE A
POTENTIAL ISSUE IN SOUTHEASTERN SASKATCHEWAN AND MANITOBA, AND THE
RAINFALL WARNING WILL LIKELY NEED TO BE EXPANDED LATER IN THE DAY AS
THE LOW AND ASSOCIATED THUNDERSTORMS CONTINUE TO DEVELOP. BY TUESDAY
MORNING, THE LOW IS PROGGED TO LIE NEAR WEYBURN AND DEEPEN TO 990 MB
OR A BIT MORE - IMPRESSIVE FOR JULY - AND THEN MOVE OFF NORTHEAST.
THE WEST SIDE OF THE LOW DEVELOPS 50 TO 70 KNOTS WINDS AT 850 MB,
BUT THE GRADIENT IS EXTREMELY CYCLONICALLY CURVED AT THE SURFACE.
STILL, HAVE GONE WITH DEFAULT 60G80 KM/H WINDS OVER SOUTHERN
SASKATCHEWAN FOR TUESDAY FOR NOW. LINGERING CONVECTION AS THE
GRADIENT TIGHTENS IS A BIT OF A CONCERN, WITH THE POSSIBILITY OF
SOME DOWNDRAFTS ADDING TO THE SURFACE WIND SPEEDS.
[/i]
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