Transcript Slide 1

01 December 2006
Typhoon Durian has killed at
least 146 people in the Philippines
and authorities say hundreds more
victims may be found in stricken
areas cut off by the storm.
Philippines
Typhoon Durian slammed into
the central and northern
Philippines Thursday with
sustained winds of 150
kilometers an hour.
Dec 1: Weather discussion …Wed 29th into Fri 1st Dec
• extreme cold
• deep inversion (2.92-0.7=2.2 km)
• low Td
• light wind
• clear, sunny
We will see a transition from
extreme cold to a moderate spell –
probably brief!
Stony Plain 12Z Wed 29 Nov. 2006
Heat island
ISSUED BY THE PRAIRIE AND ARCTIC STORM PREDICTION CENTRE OF
ENVIRONMENT CANADA AT 7:00 AM CST WED NOV. 29
FOR ALBERTA… WIND CHILL WARNINGS IN EFFECT… AS VERY COLD
ARCTIC AIR LINGERS OVER THE PROVINCE. WARMER TEMPERATURES
ON THE WAY OVERNIGHT AS STRONG WESTERLY WINDS STARTS
MIXING DOWN WARMER AIR ALOFT
Respite will be brief?
48h prog – back to N flow
GEM progs from 12Z Wed
(500 mb height & vorticity)
24h prog shows incursion
of westerly flow
Coldest air pushed
away/moderated
Wed Nov 29, 08GMT
GEMREG CUD BE A
BIT FAST WITH
LOWERING HEIGHTS
OVR WRN RGNS
AFTER MID PD
But back again
Edmonton
thknss=513 dam
GEM progs from 12Z Wed
(sfc press & 1000-500 thickness)
• freezing contour loops along coast
• how did it get that way?...
• this upper low hauled the
continental air out to the
coast… at Vancouver Int’l
Airport (on coast) temp
dropped to -11.5oC at
21LST Nov 28
CMC 700 mb analysis, 12Z Mon 27 Nov.06
Edmonton 292 dam
• Gulf of Alaska low pushing in the
moist, milder air
CMC 700 mb analysis, 12Z Wed 29 Nov. 2006
Wed Nov 29 22 GMT… ERN PAC AND WRN RGNS.. SFC TEMPS TO WARM
UP SMWHT OVR SWRN PRAIRIES DAY2. WITH S/W TROF MOVG TO
SWRN BC TONIGHT, WLY FLO ALFT WILL INSTALL ACRS
ROCKIES ALLOWING FOR QUITE SIG LEE TROF TO SHOW UP THRU
SWRN ALTA AND FOR STG-SVR CHINOOK WNDS TO SHOW UP
ALREADY TONIGHT AND PERSISTING TOMORROW. COLD AMS OVR
PRAIRIES WILL HWVR ONLY ALLOW FOR FLRYS THRU PRAIRIES
WITH SNOW AMNTS NOT EXCEEDING 5 CM FOR THE PD WITH THIS
SYSTEM.
Thurs 30 Nov.
• milder, overcast morning
• shovelled a few cm of snow
• largely clear by 1300 or earlier
EC 7AM CST THURSDAY NOV.30
PRAIRIES...LOW PRESSURE AREA NR
YEG THIS MORNING WILL TRACK
SEWD ACROSS SRN SK TODAY AND
INTO SRN MB FOR FRIDAY. WEAK
SYSTEM WILL BRING ABOUT 2 TO 4
CM OF SNOW ALONG ITS PATH.
AB..STRONG WINDS IN THE SOUTH…
ARE BLOWING SNOW AND
REDUCING VISIBILITIES. GUSTS UP
TO 110KM/H HAVE BEEN REPORTED.
ENVIRONMENT CANADA AT 2:00 PM CST THURS NOV 30.
AB..STRONG WINDS IN THE SOUTH SHOULD DIMINISH THIS
AFTERNOON. IN PINCHER CREEK AND CARDSTON WINDS ARE
GENERATING BLOWING SNOW WITH REDUCED VISIBILITIES. GUSTS UP
TO 90KM/H WERE REPORTED AROUND 18Z.
CONVECTIVE BAND DEVELOPED CENTRAL ALBERTA EARLY THIS
MORNING AND CONTINUES TO MOVE SOUTHEAST THRU THE
PROVINCE WITH LOCAL SNOWFALL AMOUNTS OF 5 CM BEING
REPORTED.
• fierce pressure gradient in the SW
• new low likely to swing the cold air
back south?
• little spot of mild air near Edmonton
• much colder on all sides
• isotherms difficult to untangle
CMC 850 mb analysis, 12Z Thurs 30 Nov.
• thickness ridge (trowal) easily seen in lee of Rockies
• strong SW current
• 24 hr prog did well
GEM prog from 12Z Wed
CMC 500 mb analysis, 12Z Thurs 30 Nov.
1) www.flightplanning.navcanada.ca/
5) Select all ASEP products (base of page)
2) Select ASEP
6) Submit
3) Departure CYVR, Enroute CYLW
7) View ASEP products (base of page)
4) Destination CYEG
8) Select Enroute air temperature
Wed mng.
• super cold
Wed evg.
• warming aloft - not much at gnd
Thurs mng.
• little change aloft
• inversion sustained, but even so
• warming below 800 mb
Thurs evg.
• cooled 15C at 500 mb
• cooled 10C at 700 mb
• little change at 850 mb
• surface inversion has mixed out (wind)
• ie. much warmer at gnd
This mng. (Friday)
• cooled about 10C below 850 mb
Sfc press & 1000-500 thickness
GEM 24 hr prog
valid 12Z Thurs
• cold air to return for 12Z Fri?
• thanks to the new low
CMC analysis 12Z Thurs
(ie. GEM 0hr prog)
GEM 24 hr prog
valid 12Z Fri
24 hr prog vld 12Z Fri
• cold air has returned
• prog good
• much colder in N. Ab
Edm 513 dam
CMC analysis 12Z Fri
• wind, but not much advection
• shouldn’t get colder in 12 hr term
• radiative cooling over night
-15
CMC 850 mb analysis, 12Z Fri 1 Dec. 2006
48 hr forecast
• flow off coast onto C. and S Alberta
• pushes back the coldest air
• if new sfc low strengthens might bring back cold next week?
• hopefully not if that 500 mb pattern persists
Edm 534 dam
144 hr (6 day) forecast - GEM global run
• C. Ab still in flow off coast
• cold air back in Manitoba where it belongs
Edm thickness 528 dam:
528 – 513  7 degrees warmer than today