839
FOCN45 CWWG 031900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT FRIDAY JULY
3 2009.
WATCHES, WARNINGS, AND STATEMENTS...NIL.
DISCUSSION...WEAK INVERTED TROF OVER SWRN SASK SET UP NOCTURNAL
THUNDERSTORMS. THOSE THUNDERSTORMS ARE DRIFTING SLOWLY EASTWARD AND
ARE NOW LOCATED WEST OF CYQR AND WEAKENING DUE TO LACK OF SUPPORT.
DYNAMICS REMAIN SOMEWHAT MORE ORGANIZED OVER SWRN SK THIS AFTERNOON
SINCE INVERTED TROF REMAINS IN PLACE. UPPER JET LOCATED OVER SRN SK
WILL PROVIDE LIFT AND COMBINING WITH LOW LVL CONVERGENCE ALONG THE
INVERTED TROF WE EXPECT THUNDERSTORMS TO DEVELOP LATE AFTERNOON AND
EVENING. 850-500 MB LAPSE RATES ARE NEAR 26C OVER SWRN SK AND LI
WILL BE NEAR -4. CAPES SHOULD REACH TOWARDS 1200-1500 J/KG OVER SWRN
SK BY EVENING. SO SOME LARGE HAIL IS POSSIBLE BUT DUE TO WEAK
WIND AND SHEAR STORMS ARE EXPECTED TO BE A PULSE TYPE NATURE.
DYNAMICS FOR THUNDERSTORMS WILL BE FAIRLY FAVOURABLE OVER SRN
MANITOBA ON SATURDAY.
UNSTABLE OVER NORTHERN ALBERTA NEAR THE UPPER LOW. TRW HAVE
ALREADY INITIATED ALONG A CONVERGENCE AREA NEAR FORT CHIPEWYAN.
CAPES NEAR 1000-1200J/KG HAVE THE POTENTIAL FOR MARGINALLY SVR
HAIL BUT LITTLE SHEAR WITH 0-6KM BULK SHEAR SITTING NEAR 10-15
KNOTS. RIDGE POKING DOWN THE FOOTHILLS GIVES AN UPSLOPE COMPONENT
HOWEVER AMDARS DATA IS SHOWING A WEAK CAP. TDS RANGE FROM 4 ALONG
THE NORTHERN FOOTHILLS TO 9 IN THE SOUTH. CAN SQUEEZE A CB OUT OF
SOME OF THE PROG TEPHIS BUT APPEAR TO BE CAPE STARVED. LAST AREA OF
INTEREST IS IN SOUTHERN ALBERTA. TRW INITIATING IN MONTANA SHOULD
HAVE A NORTHEASTERLY TRAJECTORY AND MAY CLIP THE CYPRESS HILLS
REGION. CAPES NEAR 1200J/KG AND BULK SHEAR APPROACHING 40 KNOTS
COULD GIVE SVR HAIL AND WIND. WILL HAVE TO SEE HOW THE TDS HOLD UP
AS MODELS INDICATE THE POTENTIAL FOR A SLIGHT CAP.
EASTERN ARCTIC...NIL SIG WX.
END/GERLYAND/WIELKI
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