742  
FOCN45 CWWG 241900  
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM  
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT THURSDAY  
SEPTEMBER 24 2020.  
 
ALERTS IN EFFECT... WIND WARNING FOR SOUTHWESTERN ALBERTA.  
 
SYNOPTIC OVERVIEW... ALOFT EARLY THIS AFTERNOON THERE IS A STRONG  
ZONAL PACIFIC FLOW WHICH COMES ASHORE OVER THE NORTHWESTERN CONUS.  
DOWNSTREAM THERE IS A FAIRLY SHARP SHORTWAVE TROUGH OVER EASTERN  
ALBERTA AND AN UPPER RIDGE FROM THE DAKOTAS INTO MANITOBA AND UP  
INTO THE KITIKMEOT. STRONG UPPER LOW OVER THE FAR NORTH OF QUEBEC.  
 
AT THE SURFACE THERE IS A 987 MB LOW OVER NORTHEASTERN ALBERTA WITH  
TROUGH SOUTH-SOUTHEAST ACROSS SASKATCHEWAN AND EASTERN MONTANA. WAVE  
NEAR MEADOW LAKE WITH WARM FRONT SOUTHEAST AND COLD FRONT SOUTHWEST.  
1018 MB HIGH OVER NORTHEASTERN ONTARIO WITH BROAD RIDGING UP THROUGH  
EASTERN HUDSON BAY AND INTO THE ARCTIC ISLANDS. WEAKENING 986 MB LOW  
NEAR KANGIQSUJUAQ AND POST TROPICAL STORM TEDDY, 970 MB, IS PUSHING  
FROM THE LABRADOR SEA INTO SOUTHERN DAVIS STRAIT.  
 
DISCUSSION...  
 
WESTERN PRAIRIES...AN UPPER TROUGH OVER NORTHERN AB IS SUPPORTING A  
SURFACE LOW THAT CONTINUES TO DEVELOP NORTHEAST OF EDMONTON THIS  
AFTERNOON. THIS LOW WILL TRACK NORTHEASTWARDS BRINGING 5-15 MM OF  
RAIN AND THE POSSIBILITY OF AN ISOLATED THUNDERSTORM TO NORTHERN  
AB/SK TODAY. MOIST FLOW ACROSS THE ROCKIES WILL CONTINUE TO BRING  
SCATTERED SHOWERS TO THE MOUNTAIN PARKS TODAY.  
 
STRONG WIND GUSTS, GUSTING UPWARDS OF 100 KM/H, ARE EXPECTED TO  
PERSIST OVER SOUTHWESTERN ALBERTA THROUGH THE AFTERNOON AS A LEE  
TROUGH REMAINS IN PLACE. WINDS ARE FORECAST TO GRADUALLY DIMINISH  
LATE THIS AFTERNOON INTO EARLY THIS EVENING.  
 
EASTERN PRAIRIES... STRONG LOW OVER NORTHEASTERN ALBERTA WILL TRACK  
EASTWARD TODAY. THIS AFTERNOON, IN THE WARM SECTOR, A SOUTHERLY FLOW  
WITH GUSTS UP TO 60 KM/H HAVE DEVELOPED IN SOUTHEASTERN SASKATCHEWAN  
AND SOUTHWESTERN MANITOBA. GUSTS UP TO 70 KM/H ARE BEGINNING OVER  
SOUTHWESTERN SASKATCHEWAN IN THE WEST TO SOUTHWESTERLY FLOW BEHIND  
THE COLD FRONT.  
 
RAIN ASSOCIATED WITH THIS LOW WILL MOVE INTO NORTHERN MANITOBA THIS  
AFTERNOON. THE RAIN WILL PERSIST THROUGH TO SATURDAY AFTERNOON WITH  
10 TO 30 MM OF ACCUMULATION EXPECTED. THE ASSOCIATED COLD FRONT WILL  
TRACK THROUGH THE NORTHERN GRAINBELT THIS AFTERNOON BRINGING A  
CHANCE OF SHOWERS OR WEAK THUNDERSTORMS WITH IT. OVERNIGHT, THE COLD  
FRONT WILL TRACK THROUGH MANITOBA. WITH THE STRONG HILVL JET AND MID  
LEVEL MOISTURE AND INSTABILITY THERE COULD BE ISOLATED ELEVATED  
THUNDERSTORMS OVER THE SOUTHERN HALF OF MANITOBA TONIGHT.  
 
WESTERN ARCTIC...WEAK TROUGHING ACROSS THE ARCHIPELAGO CONTINUES  
TO BRING A MIXED BAG OF PRECIPITATION TO MUCH OF THE WESTERN  
ARCTIC. FZDZ IS POSSIBLE IN COASTAL COMMUNITIES ALONG THE AMUNDSEN  
GULF AND KITIKMEOT. DENSE FOG OCCURRED OVERNIGHT IN KUGLUKTUK AND  
GJOA HAVEN AND WHILE VISIBILITIES ARE IMPROVING EARLY THIS  
MORNING, FOG PATCHES WILL REMAIN IN THE AREA OVER THE NEXT 24-36  
HRS. THE ALBERTA LOW WILL ALSO BRING 5-10 MM OF RAIN TO PORTIONS OF  
THE SOUTHEASTERN NWT OVER THE NEXT 24 HRS.  
 
EASTERN ARCTIC... THE SURFACE LOW OVER NORTHERN QUEBEC WILL WEAKEN  
TODAY AS POST TROPICAL STORM TEDDY TRACKS NORTHWARD AND TAKES OVER,  
PUSHING ANOTHER ROUND OF PRECIPITATION INTO SOUTHERN BAFFIN. 5 TO 10  
MM OF RAIN IS EXPECTED IN KIMMIRUT TODAY BEFORE TRANSITIONING TO WET  
SNOW OVERNIGHT. THIS TRANSITION HAS ALREADY STARTED AT IQALUIT,  
HOWEVER ANY SIGNIFICANT ACCUMULATIONS WILL LIKELY BE RESERVED FOR  
THE HIGHER TERRAIN SOUTHWEST OF FROBISHER BAY. CONDITIONS LOOK TO  
IMPROVE ON FRIDAY AS TEDDY BEGINS TO WEAKEN.  
 
END/MELSNESS/ALBRECHT  
 
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