Snow Storm #8: Call for Forecasts

Multi-day event at hand offering early spring snows to mid-Atlantic and coastal New England stations. HPC/s "Heavy Snow / Icing Discussion" indicated poor consensus on the details among the NWP solutions such that this event could go either way.

The forecast contest for Snow Storm #8 may be cancelled if forecasts from the next couple model runs suggest strongly the synoptics are unlikely to produce contest-worthy snows.

Cancellation notices will be posted on the web blog and the Contest/s web site only.

Deadline: 10:30 PM EST SAT...28 FEB 2009

Forecast element: storm-total snowfall
Verification begins: 12:01 AM EST SUN...01 MAR 2009

Enter your forecast here.
Follow the link from 'Enter Storm Forecast.'

Make the best forecast and you/ll win one month of FREE access to StormVista GOLD.
Details here.

More prizes will be awarded at the end of winter for the best over-all forecaster.
Details here.

As always...there/s no cost...or fee...or annoying requests for personal information to enter.

If you are making your first forecast this year or you entered the 'season-total' forecast contest...you/ll need to create an account (user name / password / valid e-mail...if you want a copy of your forecast sent to your Inbox) before entering a forecast.

Image: Winter on 5th Ave. (NYC) - Alfred Stieglitz (1892)

Sudden Stratospheric Warming - Effect on the Arctic Oscillation

Deep-layer above normal geo-potential heights (GPH) indicated by red shading in the plot area...began during the third week of JAN at the start of the long-duration SSW event.



Image courtesy CPC.

Snow Storm #8: Preview Redux

Today/s 12z NWP solutions in strong agreement with their depiction of cyclogenesis along the SE CONUS coast on SUN.

The image loops today/s 72-hour forecasts from the 12z runs of the ECMWF... UKMET...GFS...and GEM.

The upper LOW isn/t all that cold; however...strong HIGH pressure parked over eastern Canada will be needed to maintain low-level cold air. Synoptics also suggest a threat for freezing rain...especially coastal stations in New England and the mid-Atlantic/s inland stations.

NAM time-height x-sections suggest ~9 stations could be in play...more than enough to get #8 finally off the ground. After a healthy pace during the first two months of winter...FEB has turned out to be a big disappointment. Not a single contest-worthy storm. Snowfall climatology favors FEB as prime-time for most mid-Atlantic stations.

Should this scenario still seem likley tomorrow...a call for forecasts will come Friday evening with an entry deadline several hours earlier than usual Saturday evening so as to include snowfall in Pennsylvania.

Alps-like Mountain Range Under E. Antarctic Ice Sheet

"...the mountains the size of the European Alps but they also have similar peaks and valleys”... “...this adds even more mystery about how the vast East Antarctic Ice Sheet formed.”

"...“if the ice sheet grew slowly then we would expect to see the mountains eroded into a plateau shape. But the presence of peaks and valleys could suggest that the ice sheet formed quickly-we just don’t know. Our big challenge now is to dive into the data to get a better understanding of what happened” millions of years ago."

Full report here.

Cosgrove the Examiner

Blogging as Houston/s Weather Examiner.

Oriented toward KIAH / KHOU / KEFD / KGLS weather. Same detailed analysis...graphics..and imagery as his weekly newsletter (which is posted...too).

PDO - JAN '09

-1.40
17 continuous months below zero.



"The Pacific Decadal Oscillation (PDO) Index is defined as the leading principal component of North Pacific monthly sea surface temperature variability (poleward of 20N for the 1900-93 period)."

Image courtesy Joint Institute for the Study of the Atmosphere and Ocean

Cooler PAC favors more la Ninas and weaker el Ninos.

Coastal Teaser - FEB '09

ECMWF up to its old tricks...again?

Last TUE/s prog has a similar look to today/s 12z offering. An arctic HIGH pushing a strong cold front into the northern Gulf states where a low-latitude LOW would form and leave a deep carpet of snow in its wake as it climbed the coast.

So...how/d that turn out?

Only a handful of stations located in the extreme northern portions of the forecast area saw any snow. BGR observed +16"...CAR 10"...BTV 8"...CON ~8"...and PWM 7.8". Not all that far away from the action center...ORH measured 1.8".

Hoping for a better outcome this time and the start of a late winter rally. Set-up is not yet perfect...which is a good sign at this distance from VT. Today/s model run forecast the LOW to hug the coast and flood the zone with warm maritime air...all but killing snow chances for all but those stations farthest inland.

As for GooFuS...well...it lived up to its namesake.

VCP 32 - A Sorid Story

Snow Storm #8: NO SHOW

(updated below - Update2)

Originally posted MON...16 FEb 2009

12z progs were not at all encouraging.

Their portrayal of the storm complex continued essentially as a cold rain-maker for much of the forecast area with a sliver of decent snows falling beneath the northern edge of the precipitation shield.

Only four...maybe five...stations appear to be good candidates for more than a nuisance snowfall late Wednesday into Thursday. Favorable antecedent arctic air mass with dew points in the teens...breaks down quickly with the on-set of widespread veering...SE-to-SW wind profiles which are expected to dominant the storm environment.

GooFuS depicts better chances in the medium range with another potential forecasting opportunity next weekend.

Snow storm #8 awaits another day.

UPDATE:
02/17/00z progs indicate little...if any significant change to the 12z suite of solutions other than to delay on-set of precipitation by ~3 hrs at most forecast stations. Initially cold boundary layers warm to above freezing in response to unfavorable warm air advection vertical wind profiles which strongly suggest little...if any potential for a contest-worthy storm.

UPDATE2:
Verification of US model guidance of expected snowfall over the forecast area was +/-reasonable...

Storm Total Precipitation (inches observed)
CON - 7"
CAR - 4.7"
BGM - 3.8"
PWM - 3.5"
BGR - 3.4"
BTV - 2.1"
ALB - 2.1"
ORH - incomplete data (>= 2.3")

Elsewhere...plenty-o-trace amounts and < 1" reports.

Another good fall for CON...so...what/s up with that...anyway?

74" YTD. +31" departure.
Same time last year? 88"!

CON/s '08 total snowfall barely set an all-time record. LR progs suggest little change in established storm track...so more snow to come. Winter '09 could very well make it into the Top-10.

Image: Niagara Falls

Late Winter Rally

What could portend the start of a late winter rally and extra innings into March...the global models today were again dangling shiny objects before our eyes in their medium range forecasts.

Today/s ECMWF depicts an amplifying long-wave pattern over the CONUS beginning in a few days...with low-latitude cyclogenesis occurring ahead of a positively-tilted trof...and a potent nor'easter attending arctic HIGH pressure in the chamber for the last week of meteorological winter.

GooFuS offering up a similar idea...albiet a different evolution...as well.

Last snowfall forecasting event was almost three weeks ago. High time for another.

Once the storm passes...NWP suggests another arctic outbreak in the offing.

Note the deep-layer easterlies at high latitude (negative zonal wind (u) at 500 mb ==> flow into the board)...evidence of a very weak / non-existent polar vortex...and an easterly arctic jet at 10 m/s...both of which indicate favorable conditions for an arctic outbreak into the mid-latitudes.

Is this the manifestation to the sudden warming of the stratosphere observed at the end of January? If so...the timing would be right on schedule.

Also interesting is the ~10 m/s west wind over the equator in the 30 / 50 mb layer...evidence of QBO-west maintaining its strength.