2/25-27/2007 Snowfall Estimates

[donsutherland1]

Right now, I'm thinking that the GFS may be overdoing the qpf in the East and have opted for a compromise between the NAM and GFS there. At the same time, there is some possibility that the precipitation makes it farther north, but will wait for later guidance on this issue (probably until tomorrow afternoon or evening). The big winner will probably be an area running from southeastern Minnesota across to southern and central Wisconsin where a foot or more of snow may fall. I do believe that some warmer air could change the snow to a period of sleet in Milwaukee for a period of time. Nonetheless, I believe accumulations there will probably come to 10"-18".

My initial estimates are as follows:

Allentown: 2"-4"
Boston: 2" or less
Hartford: 2"-4"
Milwaukee: 10"-18" (2/24-27)
New York City: 1"-3"
Newark: 1"-3"
Philadelphia: 2" or less
Providence: 1"-3"
White Plains: 2"-4"

[Category 5]

Don, do you think this will be simular to the Valentines day Storm around Philadelphia?

[donsutherland1]

The computer guidance has come into better agreement as of the 2/25 0z runs. As a result, I believe snowfall amounts for part of the affected region will be a little greater than I had initially estimated. I'm still reluctant to push figures too high given the storm's dynamics and the risk that warmer air gets into the mid-levels of the atmosphere. Still, Allentown, Newark, and New York City should pick up at least several inches of snow. The potential does exist for greater amounts, but for me it is too soon to call for such bigger amounts. At the same time, given the consistency in the soundings so far, I believe the idea that Newark and New York City would receive mostly or all rain--a worst-case scenario--is a very low-risk.

My revised estimates are as follows:

Allentown: 2"-5"
Boston: 2" or less
Hartford: 2"-4"
Milwaukee: 10"-18" (2/24-27)
New York City: 2"-5"
Newark: 2"-4"
Philadelphia: 2" or less
Providence: 1"-3"
Toronto: 2"-4" (5.1 cm-10.2 cm)
White Plains: 2"-5"

[donsutherland1]

Category 5,

I believe this system would probably bring more in the way of rain/freezing rain than occurred in the 2/14 event. It could possibly bring more snow, too, but let's see what the 12z guidance has to say.

[Category 5]

Category 5,

I believe this system would probably bring more in the way of rain/freezing rain than occurred in the 2/14 event. It could possibly bring more snow, too, but let's see what the 12z guidance has to say.

Not good news, that stuff is much harder to deal with.

[TeeBird]

It's snowing here - lots of it - NWS says 3 - 6 inches.

Wow!

[Stephanie]

Well, I was a little surprised to put on TWC about a half hour ago and see that we're under a Winter Storm Warning because of ice!

I really expected just a sluchy mix of snow and rain - and would've prefered it.

[TeeBird]

Here in Warrenton, we have 7 inches of dense, heavy snow. But the temp is now up to above 32 and we are seeing some melting.

Wierd day

[donsutherland1]

The storm's impact in the Baltimore-Washington, DC-Hagerstown area suggests that its dynamics have been strong enough to overcome midlevel warmth. As such, the idea that its dynamics will be insignificant by the time it reaches the Philadelphia-New York City Metro Areas is probably not going to prove accurate. The idea of a fairly sharp qpf cut off across northern Connecticut and Massachusetts still appears good. Nonetheless, given the storm's more impressive dynamics and relatively stable idea on qpf, I have greater confidence in increased snowfall amounts.

My final estimates are as follows:

Allentown: 3"-7"
Boston: 2" or less
Hartford: 2"-4"
Islip: 3"-7"
Milwaukee: 10"-18" (2/24-27)
New York City: 3"-7"
Newark: 3"-7"
Philadelphia: 2"-5"
Providence: 1"-3"
Toronto: 2"-4" (5.1 cm-10.2 cm)
White Plains: 3"-6"

[cpdaman]

what do you see for the worcester area don, and i know it is probably very close to the sharp cut off line in precip but this event has surprised most weather services so far, so lets wait and see

[Category 5]

Don, your first prediction for Philly was right on

1.5"

[donsutherland1]

Verification:

Overall, not a good effort, particularly with the final forecast and with respect to DCA, IAD, and BWI, where I had expected less than 1" snowfall.

From 2/24 1:10 am:

Allentown: 2"-4"; Actual: 2.2"; Within range
Boston: 2" or less; Actual: 1.6"; Within range
Hartford: 2"-4"; Actual: 5.4"; Error: 1.4"
Milwaukee: 10"-18" (2/24-27); Actual: 11.7"; Within range
New York City: 1"-3"; Actual: 1.8"; Within range
Newark: 1"-3"; Actual: 2.1"; Within range
Philadelphia: 2" or less; Actual: 1.5"; Within range
Providence: 1"-3"; Actual: 5.5"; Error: 2.5"
White Plains: 2"-4"; Actual: 4.0"; Within range

From 2/24 11:45 pm:

Allentown: 2"-5"; Actual: 2.2"; Within range
Boston: 2" or less; Actual: 1.6"; Within range
Hartford: 2"-4"; Actual: 5.4"; Error: 1.4"
Milwaukee: 10"-18" (2/24-27); Actual: 11.7"; Within range
New York City: 2"-5"; Actual: 1.8"; Error: 0.2"
Newark: 2"-4"; Actual: 2.1"; Within range
Philadelphia: 2" or less; Actual: 1.5"; Within range
Providence: 1"-3"; Actual: 5.5"; Error: 2.5"
Toronto: 2"-4" (5.1 cm-10.2 cm); Actual: 3.7" (9.4 cm.); Within range
White Plains: 2"-5"; Actual: 4.0"; Within range

From 2/25 5:20 pm:

Allentown: 3"-7"; Actual: 2.2"; Error: 0.8"
Boston: 2" or less; Actual: 1.6"; Within range
Hartford: 2"-4"; Actual: 5.4"; Error: 1.4"
Islip: 3"-7"; Actual: 2.6"; Error: 0.4"
Milwaukee: 10"-18" (2/24-27); Actual: 11.7"; Within range
New York City: 3"-7"; Actual: 1.8"; Error: 1.2"
Newark: 3"-7"; Actual: 2.1"; Error: 0.9"
Philadelphia: 2"-5"Actual: 1.5"; Error: 0.5"
Providence: 1"-3"; Actual: 5.5"; Error: 2.5"
Toronto: 2"-4" (5.1 cm-10.2 cm); Actual: 3.7" (9.4 cm.); Within range
White Plains: 3"-6"; Actual: 4.0"; Within range