February 8-15, 2007 Idea: Cold Relaxes...

[donsutherland1]

Roman philosopher and writer Publilius Syrus once advised, “Do not turn back when you are just at the goal.” The ongoing pattern evolution has now taken Winter 2006-07 almost to the proverbial goal—that of cold and snow.

Yesterday, light snow moved into parts of the northern Mid-Atlantic region. By the time the snow ended, Newark, New Jersey had picked up 2 inches of snow and New York City saw 0.5” (reaching 1.0” for the season). A few spots in eastern Pennsylvania and central New Jersey were “buried” under more than 3” of snow, making this event a “great snowstorm” in the relatively snowless Winter 2006-07.

That snowfall likely marked the raising of the curtain on the January 28-February 20 timeframe that I continue to believe will account for a disproportionate share of this winter’s seasonal snowfall in much of the East. A weak system might trigger some additional light snowfall Tuesday night into Wednesday, particularly in southern and central New England. At this time, I also retain my confidence that the 2/1-7 timeframe will mark the start of a more widespread “snow rally” in the East and reiterate my point from the 2/1-7 discussion that there is a good chance that at least several of the big cities of the East Coast will see a moderate (4” or more) or significant (6” or more) snowfall during the above timeframe or no later than February 10. That kind of pattern would also bring with it the possibility of at least some snowfall, along with significant ice, in Georgia and the Carolinas. The “big dog” (subtropical jet) is now awakening. Soon, it could make several runs at the Southeastern, Mid-Atlantic, and New England States. That’s where the pattern is now—at least the way I see it.

With respect to the February 8-15 timeframe, I believe the period will start out quite cold but slow moderation will likely occur. At this time, no blowtorch events appear likely during the above timeframe. However, the period could see one or two days of somewhat above normal temperatures in the Eastern third of the United States as it comes to a close. Nonetheless, even with moderation, an active subtropical jet should present the opportunity for snowfall (and ice in the Southeast), possibly from warmer air overrunning a slowly retreating dome of very cold air. The pattern could grow quite amplified near or after mid-month. Another shot of cold, though not as severe as those from late January-early February is possible after mid-month. Whether or not the generally cold pattern rebuilds or the possible cold shot after mid-month gives way to more appreciable warmth will depend on whether a meaningful blocking episode develops. That is beyond the timeframe of this discussion.

The Desert Southwest will likely be warmest region relative to normal during the 2/8-15 timeframe. One or more days with much above normal warmth are possible in that area.

A few days ago, the GFS ensembles were bringing in relatively mild air to the East at the beginning of the timeframe. They are now holding off for a few more days. They have also abandoned the idea of a fairly impressive trough in the West/ridge in the East pattern. The GSM, objective analogs, and historic experience with similar NAO/PNA regimes to the present one suggest a slower arrival of milder weather and much less ridging in the East. Hence, I believe the 2/8-15 timeframe will likely start cold and then grow more moderate. No much above normal readings are likely in the eastern U.S. and Great Lakes region through the duration of the 2/8-15 timeframe.

My thinking for the average temperature anomalies during the 2/8-15 period is as follows:

Average Regional Temperature Anomalies (2/8-15):
Northeast: Somewhat below normal
Mid-Atlantic: Somewhat below normal to near normal
Southeast: Near normal
Great Lakes: Somewhat below normal
Northern Plains: Somewhat below normal
Central Plains: Somewhat below normal
Southern Plains: Somewhat above normal
Pacific Northwest: Near normal to somewhat above normal
Southwest/Rest of West Coast: Above normal

For the major cities from Washington, DC to Boston, the 2/8-15 period is likely to feature:

- Nights generally in the teens and 20s, especially in Boston and 20s in New York City, Philadelphia, and Washington, DC
- Days mainly in the 30s in Boston and 30s and 40s in New York City, Philadelphia and Washington, DC.
- At least one day with a low temperature in the teens in all of the above cities.
- One day with a high temperature at or above 50° in Washington, DC

In the Southeast, Atlanta will likely see highs generally in the 40s with some 50s. Lows should generally be in the 20s and 30s with a few 40s later in the period. Elsewhere, Burlington will likely see highs mainly in the teens and 20s. Lows should be in the single digits.

[MetSul Weather Center]

Dear Don

The latest Brazilian Global Model indicate warmer conditions in the Northeast in the second week of February. Here is the link to the NYC meteogram.

http://www.cptec.inpe.br/cgi-bin/pre...27&submit.y=13

I hope this link may be useful.

Alexandre

[donsutherland1]

Thank you, Alexandre. I appreciate the link.

Best wishes.

[JBG]

Dear Don

The latest Brazilian Global Model indicate warmer conditions in the Northeast in the second week of February. Here is the link to the NYC meteogram.

http://www.cptec.inpe.br/cgi-bin/pre...27&submit.y=13

I hope this link may be useful.

Alexandre

When (if ever) does the Brazilian global model posit sustained cold for the Northeast US?

[Jim Cantore]

I just saw on the news that the highs might struggle to reach 20 in the Philly area next week.

Key word, "Next week"

[Stephanie]

I just saw on the news that the highs might struggle to reach 20 in the Philly area next week.

Key word, "Next week"

YUCK!!!

[Jim Cantore]

I just saw on the news that the highs might struggle to reach 20 in the Philly area next week.

Key word, "Next week"

YUCK!!!

I disagree.

[angelwing]

Unless we can do some of this