March of Winter/s End

Meteorological winter...defined as the three coldest months (DJF)...comes to a close in a few days but winter wx can and does continue throughout March over much of New England.

The latest monthly temperature outlook from the Climate Prediction Center (CPC) indicates above normal mean temperatures over the western quarter of the CONUS. The warm anomaly suggests the expected position of the mean long wave ridge axis.

If there/s a ridge in the west...then it follows there/ll be a trof in the east...which is good news for squeezing another storm or two out of this otherwise disappointing winter.

Coastal Teaser #5

MR progs depict active southern stream next week and the possibility for a coastal storm passing near the 40°N / 70°W 'benchmark.' Storms passing over the 'benchmark' generally produce respectable snows over SNE.

Latest GooFuS point forecasts suggest low levels would be cold enough to support frozen precipitation over interior portions of the M-A and NE.


Click image to animate loop.

Big Changes @ High Latitudes

The ECMWF/s 12z forecast from Friday shows an atmosphere quite different than the one observed all winter. The deep layer flow near the pole for much of the winter has been westerly except for the past few weeks when the weather turned bitterly cold in the E.


The ECMWF progs show a troposphere and stratosphere bathed in easterlies and the stratosphere warmed 20°C by February 24.

A warm stratosphere comes about when the troposphere is cold (lower heights in the troposphere means lower and therefore warmer heights in the stratosphere).


Deep easterlies mean the pole is dominated by HIGH pressure. Easterlies weaken the polar vortex (PV) or shift its position and leads to an increase in general storminess in the mid-latitudes.

Broad HIGH pressure at the poles is observed during the negative phases of the Northern Atlantic (NAO) and Arctic oscillations (AO). The negative phase favors arctic outbreaks in the E CONUS.

Taken together...deep easterlies...-AO...and -NAO suggest a good potential for additional winter wx along the EC toward the end of the month.

Click on cross-section images to animate.

Contest # 1 - Final Results

Full verification table and summary @ the Contest web site. Follow the links to 'Latest Forecasts' and 'Latest Results.' Finally...a contest snowstorm! Never in the eight-year history of the NE.Wx Snowfall Forecast Contest has the first storm formed so late in the season. In every other year...the first storm appeared no later than the end of December.

This storm was worth the wait. Ever changing progs in the medium range carried into the short-range period making this a difficult forecast. Loaded with sub-tropical moisture...a frisky short wave...and deep enough arctic air...record daily snowfall were observed across portions of central NY and VT. Arctic air lost out closer to the coast where strong maritime influences kept snowfall to a minimum.

1st Place - TQ
SUMSQ Error: 197.1”
SUMSQ - Z: -0.460
STP: 156.6” (4th)
TAE: 52” (2nd)
AAE: 2.08” (1st)

2nd Place - bruced
SUMSQ Error: 216.1”
SUMSQ - Z: -0.450
STP: 165.5” (6th)
TAE: 54.4” (3rd)
AAE: 2.27” (3rd)

3rd Place - donaldsutherland1
SUMSQ Error: 226.6”
SUMSQ - Z: -0.445
STP: 150.25” (1st)
TAE: 54.5” (4th)
AAE: 2.37” (4th)

Honorable Mention - noreasterjer07
SUMSQ Error: 253.5” (4th)
SUMSQ - Z: -0.427
STP: 188” (13th)
TAE: 49.1” (1st)
AAE: 2.23” (2nd)

SUMSQ: sum of square errors
STP: storm total precipitation
TAE: total absolute error
AAE: average absolute error

Contest # 1 - Verification

(Update 1) (Update 2)



Tracking down snowfall reports needed to verify forecasts sure ain/t what it used to be. The latest F6 and CDUS41 reports are now readily available through IWIN. Hot links take you directly to the latest bulletin.

Nothing like it used to be.

Many stations filed their final snowfall reports with yesterday/s CDUS41 reports. Additional snowfall reports are expected tonight from stations along the northern tier of the forecast area.

This post will be updated tomorrow morning with preliminary storm-total snowfall reports for the forecast verificaton. Snowfall totals are subject to challenge and may change...where appropriate.

Update 1
Preliminary Snowfall Totals
CAR 14.30
BGR 5.20
PWM 9.90
CON 9.50
BTV 25.70
BOS 2.50
HYA 0.00
ORH 10.30
PVD 0.50
BDR 2.00
BDL 2.40
ALB 16.80
BGM 18.50
ISP 0.50
JFK 1.50
ABE 7.60
MDT 6.00
PHL 4.30
ACY 0.80
EWR 3.40
BWI 2.70
IAD 3.00
DCA 2.20
SBY 0.50
RIC 0.00
ORF 0.00
RDU 0.00
TOT 150.10

Update 2
The preliminary storm-total snowfall amounts will become final on Saturday morning if there are no challenges. Final results will be posted Saturday evening.

Contest # 1 - The Day After

GOES12 1615z Visible - click to enlarge

Contest # 1 - Teleconnections

AO nice and low...NAO about normal - not that there/s anything wrong with that --...and PNA running a little hot.

Contest # 1 - Day Two Leader Board

Based on climo reports for 13th and 14th.
All precincts have not reported final results.

donsutherland1
TQ
bruced
bubbler86
MatthewRydzik
noreasterjer07
herb@maws
Raven
emoran
jefcled
shanabe
mattmfm
cdog127
ilibov
steveo
Donald Rosenfeld
noreaster
mitchel volk
joesco

Center of Attention

The surface LOW pressure center passed just S of Westhampton Beach , NY...home of the KFOK ASOS this afternoon. ASOS observed it passage just before 3 PM EST (20z).

Note the breezy 17G25KT wind from the ENE back into NW then N...and diminish to all of 3KT. Blowin' like stink one minute...almost dead calm the next. About 35 minutes of becalmed conditions ended when the backside of the LOW blew in on a 24G33KT wind bringing FZRA and sharply colder temperatures with it. The temperature fell 8°C (~14°F) in about 90 minutes. The 40°F mP dew point dropped to 25°F in cP.

141853Z 04017G25KT 1SM -RA BR BKN006 OVC010 03/02 A2899
141914Z 07011KT 1 1/4SM -RA BR OVC004 03/02 A2896
141953Z 33005KT 1 3/4SM -RA BR OVC004 05/04 A2895
142003Z 35003KT 2SM BR OVC004 04/03 A2894
142017Z 31007KT 1 1/2SM BR BKN004 OVC007 04/03 A2895
142043Z 33024G33KT 2SM -FZRA BR OVC002 M01/M02 A2896
142053Z 32023G29KT 2SM -FZRA BR OVC004 M02/M03 A2898
142116Z 32024G32KT 3SM -FZRA BR OVC004 M03/M04 A2903
142121Z 32027G34KT 2SM -FZRA BR OVC006 M03/M04 A2903
142129Z 31024G34KT 1 1/4SM -FZRA BR OVC006 M03/M04 A2904

The reason the horizontal wind stops blowing in the center of circulation is b/c all the air movement is going straight up.

Contest # 1 - Day One Leader Board

With plenty-o-storm left to go...the Day One leader board has bubbler86 in 1st, jefcled 2nd, and donsutherland1 3rd.

Not all precincts have reported final amounts.

bubbler86
jefcled
donsutherland1
herb@maws
MatthewRydzik
TQ
emoran
bruced
Raven
mattmfm
shanabe
cdog127
noreasterjer07
ilibov
steveo
noreaster
Donald Rosenfeld
mitchel volk
joesco


Click image to animate.

Secondary surface development over SC around 14/00z. Initial surface LOW pressure of 1003 mb falls rapidly between 06z and 18z to 978 mb @ 21z.


Click image to animate.

Center of circulation just E of Long Is., NY. Greatest pressure falls INVOF PWM indicating short-term storm track. Recent 88D VAD data showed center of 700 mb circulation south of BTV...east of ALB... and NW of GYX strongly suggesting the system still has some tilt with height left in it and further deepening of the surface LOW is likely.


GOES8 @ 3:45 PM EST (2045z) observation of frontal boundaries over the western Atlantic...the secondary LOW E of LI, NY...strong arctic CAA over SNE coastal waters producing FZRA INVOF Westhampton Beach, NY (KFOK)