FOCN45 CWWG 262000
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CST THURSDAY
NOVEMBER 26 2009.
SIG WX BULLETINS... NO WARNINGS CURRENTLY IN EFFECT.
DISCUSSION... BROAD UPPER RIDGE OVER THE PRAIRIES WITH PLENTY OF
MILD AIR ASSOCIATED. 850 ANALYSIS SHOWS FAIRLY SHARP WARM FRONT FROM
FORT SMITH SEWD ACROSS ERN SK AND INTO THE DAKOTAS. SOME FRZG RAIN
REPORTED OUT AHEAD OF THIS FRONT BUT THE SUPPORT FOR THIS IS
WEAKENING AS THE PRECIP MOVES TO THE NORTH AND AWAY FROM THE ABV
FRZG LAYER.
ANOTHER IMPULSE NOW SEEN ON WATER VAPOUR IMAGERY PUSHING TOWARDS THE
NORTHWESTERN STATES IS FORECAST TO SPIN UP A SFC LOW WHICH WILL
TRACK EASTWARD NEAR THE PRAIRIES INTL BORDER OVER THE NEXT COUPLE OF
DAYS. MAIN FORECAST PROBLEM IS THE TRACK OF THE PRECIPITATION, AND
PRECIP TYPING. FRZG RAIN CONTINUES TO BE A THREAT FOR PORTIONS OF
THE SOUTHERN PRAIRIES, BUT WHETHER IT WARRANTS NEW WARNINGS IS TOUGH
TO SAY AT THIS POINT. SNOWFALL SHOULD STAY SUB-WARNING, BUT WITH
THE RELATIVELY STRONG MID AND HIGH LEVEL JETS AND BAROCLINICITY OVER
SOUTHERN BC CANNOT DISCOUNT THE POTENTIAL FOR A NARROW BAND OF
HEAVIER SNOW SETTING UP.
QSTNRY HIGH OVER THE MELVILLE PENINSULA, BOTH SFC AND ALOFT IS
MAINTAINING A VERY QUIET WEATHER PATTERN OVER THE EASTERN ARCTIC.
 WRN PRAIRIES..UPPER FRONT EXTENDS ACROSS ALBERTA TODAY
WITH STG JET ALOFT. FRONT DROPS SLOWLY SWD NEXT 24 HRS AS ALBERTA
CLIPPER FORMS IN SRN AB TDA AND THEN MOVES QUICKLY EWD. POTENTIAL
FOR FZRA WITH THIS SYSTEM WITH THE BEST CHANCE IN DRUMHELLER AND
CORONATION. CURRENT PROGS ARE SHOWING LESS OF AN AFL HOWEVER
POTENTIAL IS STILL GOOD. WILL HAVE TO SEE HOW THE SYSTEM DEVELOPS
SINCE MODELS HAVE BEEN SHIFTING THE FZRA LOCATION AROUND. BEHIND THE
LOW UPSLOPE FLOW SHOULD BRING SNOW TO THE SOUTHERN FOOTHILLS. AS A
RIDGE SLUMPS DOWN THE FOOTHILLS BEHIND THE LOW AN UPSLOPE SITUATION
SETS UP SOUTH OF CALGARY. AMOUNTS MAY APPROACH WARNING CRITERIA.
IN NORTHERN SASKATCHEWAN SNOWFALL AMOUNTS NEAR 10 CM ARE EXPECTED
ALONG THE TROWAL. STONY RAPIDS IS AT 8 CM AND SHOULD BEGIN TO TAPER
OFF THE NEXT FEW HOURS AS HIGHER CLOUD MOVES PAST.
WRN ARCTIC..LOW PRESSURE CENTER NEAR GREAT SLAVE LAKE WILL MOVE
NORTHEASTWARDS STRENGTHENING THE GRADIENT OVER CAMBRIDGE BAY. WINDS
NEAR 40 KM/H WITH LIGHT FALLING SNOW MAY OCCASIONALLY REDUCE
VISIBILITIES.
END/MELSNESS/WIELKI