Thursday, March 26, 2009

Friday, March 20, 2009

Thursday, March 12, 2009

Friday, March 6, 2009

Snowfall Summary - February '09

February/s storm track...such as it was...returned to the upper mid-west and the Great Lakes region where it was at the start of winter.

Not a single contest-worthy storm occurred...although a handful of extreme northern forecast stations observed 8 - 16" snows.

Bangor (BGR) had the best of it...racking up 160% of normal (15.5") monthly snowfall. FEB/s total-snowfall alone made up 49% of the station/s D-J-F-M average snowfall and with one month to go...BGR is 148% of normal.

Philadelphia (PHL) was the only other forecast station to observe more than normal snows for FEB...which is rather odd...considering FEB is prime-time for most mid-Atlantic stations. PHL 8.4" was 118% of normal (7.1")and 42% of an average season/s snow total.

In spite of a lackluster month...Bridgeport(BDR)...Boston (BOS) and Concord (CON) stand @ 136%...135%...and 125% of normal snowfall for the D-J-F-M period.

Other stations above normal currently with one month left to go:
PVD (116%)
BTV (115%)
PWM (110%)
ORH (104%)

Caribou (CAR) is all but normal (98%) and will easily come in slightly above by 31 MAR. In light of the recent MAR 2 snows...most other stations have a good chance of reaching season-normal.

All but certain losers appear to be MDT...BWI...IAD...DCA...SBY...RIC...and ORF.

Green => Top 25%
Red => Bottom 25%

WFO Monthly/Daily Climate Data

NCDC Period-of-Record Snowfall Climatology

Thursday, March 5, 2009

QBO - February '09

(Updated)

FEB/s QBO weighs in @ 12.33...a seven month relative maxima coming after three consecutive months of increasing values during which time decreases would otherwise have been expected.

Going back through past positive cycles since 1948 finds a similar fluctuation happened in 1985/6 (16 months > 0). If past is prologue then QBO won/t flip until the start of astro-summer.

(end update)

Original posted 2/26/09



FEB/s QBO should come in @ 10+ when it/s officially reported in early MAR...right where it/s been for the past 8 of 9 months. It dipped briefly below 10 to 9.12 in NOV '08.

Also noteworthy is the lingering...last gasp evidence of this winter/s long-duration SSW event still underway...marked by deep easterly wind (negative values into the board; shaded blue in the plot area over the Pole) in the 10 - 100 mb layer.

NOAM Temperature Departures - February '09

Temperature anomaly forecast...



Observed temperature anomaly ...



Precipitation anomaly forecast...



Observed precipitation anomaly...

Interim Standings

After eight snow storms... donsutherland1 maintains his near season-long and commanding lead... shanabe and Donald Rosenfeld hold onto second and third...respectively.

Several forecasters ranked in previous Interim Standings had not entered at least six forecasts and were not eligible for this summary under the ‘two-thirds’ rule.

Full interim forecaster error statistics table and charts here.

Forecaster storm summary data here.

SUMSQ errors for each contest snow storm are normalized with a 'Z-score'...then averaged to compute the standings. Forecasters who have entered at least 2/3 of all snow storm contests are included in the standings.

If a forecaster has participated in more than two-thirds of all snow storm contests...then Z-scores from two-thirds of their best forecasts are used to calculate Interim and Final standings. Same idea as dropping the lowest quiz score before the final grade is computed.

Previous Interim Standings here.

Wednesday, March 4, 2009

Snow Storm #8: Results

NEWxSFC Chief forecaster donsutherland1 made the best synoptic-scale snowfall forecast for Snow Storm #8...where all 27 stations were in play.

His SUMSQ error of 106" (Z-Score -0.945) was 64% better than the average error of 293". Donsutherland1 finished in second place for 'Total Absolute Error' (42.5") and Average Absolute Error' (1.57"). His STP forecast of 174.4" was within 5% of the observed 169.9" STP.

Donsutherland1 had the lowest station errors @ HYA...ORH...ABE... MDT...PHL...and DCA.

Congratulations Donsutherland1


Donsutherland1 wins one free month of StormVista GOLD for his forecasting acumen.

2nd Place: Herb @MAWS (116.8"; -0.890)
3rd Place: dmcguriman (127"; -0.839)
Honorable Mention: Raven (164"; -0.651)

Full forecast verification and results summary here.

Snow Storm #8: Preliminary Verification

(updated below - Update2)

Preliminary storm-total snowfalls for Sunday and Monday from CDUS41...PNS...and CF6 bulletins.

Eight new daily records.
SUN...01 MAR 2009
ISP - 3.8" (2.1"; 2005)
ACY - 4.6" (1.7"; 1968)

MON...02 MAR 2009
ORH - 9.3" (7"; 1948)
PVD - 10" (7.1"; 1996)
BDR - 7.6" (4.5"; 2006)
BDL - 7.9" (7.9"; 1948)
ISP - 9.7" (5"; 1996)
PHL - 5.6" (5"; 1914)

CON snowfall was missing from CDUS41 at post time. GYXPNS bulletin carried a storm-total snowfall report of 9" as of 7:28 AM MON...02 MAR 2009 with 'Heavy Snow' in Remarks.

METAR P-group reported 0.17" liquid between 7:32 AM and 12:51 PM...after which light snow continued with no additional accumulations recorded by the tipping bucket. The 9" snowfall reported in the PNS bulletin had a liquid equivalent of 0.67" and a SN:H2O of 13.4:1. An estimated 2.3" of additional snow fell @ CON between 7:32 AM and 12:51 PM.

The 11.3" storm-total snowfall verification value for CON will be revised should WFO GYX get around to reporting the actual amount before the final results are posted.

Please report errors in Remarks.

Final results and storm summary Wednesday evening.

Update
WFO GYX published snowfall data in the F-6 for CON Tuesday afternoon.
3/1: 0.5"
3/2: 11"
STP = 11.5"

Update2
WFO BOX corrected the F-6 bulletin/s MAR 2 daily snowfall report for BOS. The corrected value is 6.9" for a two-day STP of 8.5".

WFO AKQ corrected the F-6 bulletin/s MAR 2 daily snowfall report for RIC. The corrected value is 2" for a two-day STP of 6.3".

Two more stations set new daily snowfall records on MAR 2.
EWR - 5.3" (4.3"; 1996)
BWI - 4.7" (3.7"; 1969)

Snow Storm #8: Aftermath Imagery



Note bay-effect streamer downwind of Delaware Bay/s mouth. Strong 850 mb cold air (9°F) advection over relatively warm (L30s) waters.

Courtesy NASA/s Earth Observatory Image of the Day. Hi-res version here.

Tuesday, March 3, 2009

Snow Storm #8: Gravity Wave

Tony Wood reporting for the Philadelphia Inquirer...

"Just before midnight Sunday, meteorologists said, a band of rapidly rising air - part of what is known as a "gravity wave" - developed in the upper atmosphere from eastern Virginia into eastern New Jersey. And this was a particularly potent one.

"For the next few hours, it generated heavy snow in South Jersey, with 10.5 inches in Hammonton by daybreak, and powerful wind gusts of 60 m.p.h. in Atlantic City and 59 m.p.h. in Cape May.

"Meanwhile, the wave temporarily would shut off snow to areas to the west, said Louis W. Uccellini, director of the National Center for Environmental Prediction..."

Sunday, March 1, 2009

Snow Storm #8: The Forecasts



12 forecasters. 2 rookies and 10 veterans.
Forecasters are ranked in the table above by storm-total precipitation (STP)

Station forecasts here.



A real snow storm this go'round with all stations in play. Looks to be a good... old-fashion...and long overdue...I-95 corridor event from RIC to BGR.



What/s up with that conventional wisdom about -NAO and mid-Atlantic snow storms?



LOW pressure along the SE coast @ 12z...ready to hang a left for a run up the coast on its way toward 40N/70W.