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12Z Wed (analysis)
CMC prog from 12Z Wednesday
Here is the 0h (analysis)
…what development was forecast?
Lecture 26: Map discussion
00Z Thu
12Z Thu
 analysis
12Z Thu
522
• invasion of colder sfc air in N. Ab
• storm in E. Canada
00Z Fri
• high in N. Alberta 1032 mb
• develop strong Gulf of Alaska low
• eastern storm below 984 mb
For 5 pm MST Thursday…
Thu Nov 09 22:10:15 2006 GMT… W COAST:
GLFALSK LO WILL REMAIN NRLY STNRY … BULK OF PCPN WILL HIT
THE COAST BY BTWN T+12 AND T+36H WITH MAX AMNTS FOR WRN
VRILS. LIQUID PCPN WILL TAPER DOWN BYND T+36H, SHIFTG TO
NWRN US COAST. BUT SNOW WILL INCRSD BYND MID PD ALNG SRN
PAC RANGE, THEN INTNSFYG ALNG THE SRN FOOTHILLS LATER IN
THE PD. UP TO 15CM IS FCST BY MODEL FOR THE FOOTHILLS.
STORM FORCE WINDS WILL AFFECT BC COAST ON D1 BUT WILL
RPDLY WKN AS UPR TROF MVS INLAND ON D2.
PRAIRIES : SIG LO FCST TO DVLP OVR SRN AB LATE IN THE PD WILL
BRING LGT SNOW TO THE SRN PRAIRIES, BUT WITH MXD OR LIQUID
PCPN OVR XTRM AB WITH WRM OVRNNG .
5 am + 12  5 pm Thurs ?
ISSUED BY THE PRAIRIE AND ARCTIC STORM PREDICTION CENTRE OF
ENVIRONMENT CANADA AT 2:00 PM CST THURSDAY NOVEMBER 9 2006.
PRAIRIE DISCUSSION...ARCTIC HIGH ESTABLISHED OVER CENTRAL
AB/SK. EAST OF HIGH WIDESPREAD BOUNDARY LAYER CLOUD. PBL IS
VERY UNSTABLE AND WIDESPREAD FLURRIES ARE PRESENT. COLD AIR
ADVECTION OVER LARGER LAKES CONTRIBUTING TO BL
MOISTURE. PRECIPITATION IS MORE ENHANCED IN OFFSHORE FLOW
FOR LARGER LAKES.
WEST OF THE HIGH...NELY LO LVL FLO IN COMBINATION WITH
OVERRUNNING MID TO UPPER LVL FLOW PRODUCING SOME
PRECIPITATION IN UPLOPE AREAS OF SW SK AND WRN AB. THIS WILL
CONTINUE AS THE SFC HIGH SLOWLY DRIFTS SOUTHEASTWARD.
How did the prog do?
- main features were captured
• arctic high in N. Alberta 1027 mb
• Gulf of Alaska low
trowal
CMC “complete” surface analysis 18Z Thurs 9 Nov., 2006
• arctic high 1028 mb and rising faster on its east flank – ie. moving eastward
• light sfc winds
CMC “preliminary” surface analysis 18Z Thurs 9 Nov., 2006
• surface warming occurred
• may be related to sink in lee of
Rockies
Sea surface winds from Quikscat polar-orbiting satellite
• derived from radar backscatter
reveals the Gulf of Alaska low
… zooming in … Quikscat winds … 22Z Thurs 9 Nov. 2006
• strongest winds on W flank –
consistent with isobar packing
on CMC analysis?
CMC surface analysis 18Z Thurs 9 Nov., 2006
CMC surface analysis 18Z Thurs 9 Nov., 2006
CMC surface analysis 00Z Fri 10 Nov., 2006
CMC surface analysis 00Z Fri 10 Nov., 2006
CMC surface analysis 18Z Thurs 9 Nov., 2006
• contours labelled in [cm]
http://ursus-marinus.ncep.noaa.gov/sst/oper/global_anomaly_oper0.png
• Note the El Nino pattern
• 850 mb lee trowal in west central Ab
• weak lee trough visible at 850, 700
• causal SW current at 700 mb evident
• lee downslope adiabatic warming –
larger T-Td in lee
• the coastal low obviously responsible
for our slightly milder conditions
• weak flow aloft – slow evolution today?
CMC 850 mb and 700 mb analyses
12Z Fri 10 Nov., 2006
• arctic high now centred over Saskatchewan (has moved east as anticipated)
• weak irregular sfc lee trough (hard to see due to “noisy” in isobars) is deepening
• cyclogenesis expected – new lee storm by 12Z Sat and moves to Sask by 00Z Sun
PRAIRIE AND ARCTIC STORM PREDICTION CENTRE 7:00 AM CST FRIDAY
NOVEMBER 10 2006.
UPPER DISTURBANCE WILL CROSS MOUNTAINS OVERNIGHT BRINGING
WARMER AIR IN ALOFT. LOW DEVELOPS IN CENTRAL ALBERTA AND
TRACKS ACROSS CENTRAL SASKATCHEWAN WITH AREA OF SNOW TO
THE NORTH OF LOW. WARMER AIR RETURNS TO THE SOUTHERN
PRAIRIES FOR THE WEEKEND. STRONG SOUTHERLY WINDS ARE
EXPECTED FOR LATE IN THE DAY SATURDAY
• moist lower tropos.
• weak winds
• not much change likely during
the day