CMC prog from 12Z Wednesday Here is the 0h (analysis) …what development was forecast? Lecture 26: Map discussion 12Z Wed (analysis)

00Z Thu

invasion of colder sfc air in N. Ab storm in E. Canada  analysis 12Z Thu Z Thu

high in N. Alberta 1032 mb develop strong Gulf of Alaska low eastern storm below 984 mb For 5 pm MST Thursday… 00Z Fri

Thu Nov 09 22:10: 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 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.

CMC “complete” surface analysis 18Z Thurs 9 Nov., 2006 arctic high in N. Alberta 1027 mb Gulf of Alaska low How did the prog do? - main features were captured - main features were captured trowal

CMC “preliminary” surface analysis 18Z Thurs 9 Nov., 2006 arctic high 1028 mb and rising faster on its east flank – ie. moving eastward light sfc winds

surface warming occurred may be related to sink in lee of Rockies

Sea surface winds from Quikscat polar-orbiting satellite derived from radar backscatterreveals the Gulf of Alaska low

… zooming in … Quikscat winds … 22Z Thurs 9 Nov strongest winds on W flank – consistent with isobar packing on CMC analysis?

CMC surface analysis 18Z Thurs 9 Nov., 2006

CMC surface analysis 00Z Fri 10 Nov., 2006

CMC surface analysis 18Z Thurs 9 Nov., 2006

contours labelled in [cm]

Note the El Nino pattern

CMC 850 mb and 700 mb analyses 12Z Fri 10 Nov., 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-T d in lee the coastal low obviously responsible for our slightly milder conditions weak flow aloft – slow evolution today?

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 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