813
FOCN45 CWWG 202000
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CST FRIDAY
NOVEMBER 20 2009.
SIG WX BULLETINS...BLIZZARD WRNG FOR REPULSE BAY AND WINTER STORM
WATCH ALONG THE HSNBA CST.
DISCUSSION...AT 500 MB UPR TROF OFF BC CST AND STG SWLY FLOW OVER
PRAIRIES. AT THE SFC 1004 MB LO JUST W OF REPULSE BAY, 2ND 1004 MB LO
JUST NE CHURCHILL. RDG OF HI PRES THRU CNTRAL NU INTO NRN SK. WK TROF
IN SRN AB XTNDG FROM A LO IN CNTRL BC.
OVER ERN PRAIRIES..MILD SOUTHWEST FLOW REESTABLED WILL RESULT IN
CONTINUING UNSEASONABLY WARM TEMPERATURES WITH A FEW RECORD HIGHS
LIKELY TO FALL.
WRN PRAIRIES..LO OFF BC COAST MOVG TO LIE CENTRAL BC BY 00Z AND THEN
SOMEWHERE NEAR YLL BY 12Z SATURDAY. TROF HANGS BACK FROM LO THROUGH
GREAT SLAVE LAKE. EXPECT SNOWFALL AMOUNTS IN THE 2-4 CM RANGE
WITH LOCAL 5 CM VICNITY LOW AND ALONG TROF. ALSO RISK FZRA VICINITY
LOW ESPLY NERN QUAD AS WARM AIR OVERRUNS ARCTIC AIR CUTTING
UNDERNEATH. AT THIS POINT WILL JUST GO WITH RISK FZRA IN THE
AFFECTED AREAS.
ERN ARCTIC..FEW CM OF NEW SNOW THRU REPULSE BAY TDY. AS LOW PUSHES
EWD, AND RDG BUILDS IN, GRADIENT WILL STRENGTHEN. NLY WINDS OF 50 G
70 XPCTD ALONG WITH NEW SNOW AND FALLING TEMPS SHUD COMBINE PRODUCE
BLIZZARD CONDNS THERE TMRW. IN THE LONGER RANGE, A LOW IN CNTRL BC
WILL NTNSFY AS IT MOVS INTO NRN MB LATE IN THE DAY ON SAT GVG A STG
ELY GRADIENT ALONG THE HSNBA CST. WITH SOME FRESH SNOW AND STG ELY
WINDS, POOR VSBYS IN SN/BLSN WILL LKLY RESULT. TEMPS A BIT ON THE
MILD SIDE, WHICH MAY HAMPER FULL BLOW BLIZZARD. TOO CLOSE TO CALL SO
WILL ISSUE A WATCH FOR THESE RGNS WITH UPDATE THIS AFTN.
WRN ARCTIC..GENERALLY HAVE WIDESPREAD CLOUD AND SCATTERED FLURRIES.
DEVELOPING TROF ALONG MACKENZIE VALLEY IN CONJUNCTION WITH RIDGE
THROUGH CENTRAL ARCTIC WILL GENERATE BRISK SOUTHEAST FLOW OVER
CENTRAL NWT AND BANKS AND WRN VICTORIA ISLANDS. WILL LIKELY SEE
STRONG EASTERLIES AND BLOWING SNOW AT YHI BUT WITHOUT NEW SNOWFALL
DO NOT EXPECT BLIZZARD CONDITIONS..
END/SLIPEC/MACKAY
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