March 5-7, 2007: Impressive Cold Shot

[donsutherland1]

If one examines the latest computer guidance, both from the 3/1 12z run of the ECMWF and the 3/2 0z run of the GFS, one finds the model suggesting a shot of possible extreme cold for March centered around March 6 12z. The data from this guidance follows:



In the past, powerhouse storms such as the one that has ravaged Alabama with tornadoes and brought severe blizzard conditions to parts of Minnesota, have pulled exceptionally cold air into the United States in the past. For example, record cold followed the 1993 Superstorm. The 500 mb pattern forecast for 3/6 0z resembles that in which some very cold air masses chilled the eastern U.S. and southern Canada in the March 1-10 timeframe.

Forecast 500 mb Anomalies for 3/6 0z:


Composite Anomalies for Select Cold Air Masses for the March 1-10 timeframe (1950-Present):


Composite Anomalies for all situations in which the temperature reached the teens or colder (-7.2°C or colder) in New York City and between -5°F (-15.0°C) and 15°F (-9.4°C) in the March 1-10 timeframe:


The 500 mb anomalies forecast for 3/6 0z reasonably resemble the two historic composite case. The select Arctic outbreaks for which the forecast anomalies most closely resemble were those that occurred in March 1960, March 1978, and March 1996. The lowest readings for those air masses were:

March 1-6, 1960:
Boston: 15°
Burlington: -2°
New York City: 18°
Philadelphia: 17°
Toronto: -1° (-18.3°C)

March 1-6, 1978:
Boston: 16°
Burlington: -6°
New York City: 16°
Philadelphia: 8°
Toronto: 1° (-17.2°C)

March 1-4, 1996:
Boston: 20°
Burlington: 10°
New York City: 19°
Philadelphia: 18°
Toronto: 8° (-13.3°C)

Looking more closely at the above anomalies, one should note that the forecast 500 mb anomalies are a little farther to the north than those depicted in the historic composites. At the same time, snow cover is not likely to be present in Boston, New York City, or Philadelphia. Therefore, that means reduced radiational cooling.

Taking all the factors—historic, synoptic, and modeled—into consideration, I believe this short but sharp cold outbreak will likely see the temperature fall to 5° (-15°C) or below in Burlington and Toronto, 15° (-9.4°C) or below in Boston, and the teens (-7.2°C or below) in New York City and Philadelphia. There is a chance that either Toronto or Burlington sees a low temperature below 0° (-17.7°C). Boston has a chance to see a temperature below 10° (-12.2°C).

[tropicana]

Yes, the Environment Canada official forecast is now calling for a low temperature on Tuesday morning (march 6) of MINUS 22C .
This is fairly far from the record low for that date ( -27.8C in 1948 **2nd coldest temp ever recorded during any March).

Still, if it falls to minus 22C next week, just for statistical purposes, it has been as cold or colder than that only 8 times in the historical past in Toronto during March.
The last time a record low was broken during March in Toronto was in 2003, and it happened twice (on March 3 and March 10th). And just for info, the coldest temp during March in Toronto is -28.9C set Mar 4 1950.

[Category 5]

Hopefully some more ingredients come in and maybe that storm of the century a local met predicted in 2001 will finally get here.

[donsutherland1]

Yes, the Environment Canada official forecast is now calling for a low temperature on Tuesday morning (march 6) of MINUS 22C .
This is fairly far from the record low for that date ( -27.8C in 1948 **2nd coldest temp ever recorded during any March).

Still, if it falls to minus 22C next week, just for statistical purposes, it has been as cold or colder than that only 8 times in the historical past in Toronto during March.
The last time a record low was broken during March in Toronto was in 2003, and it happened twice (on March 3 and March 10th). And just for info, the coldest temp during March in Toronto is -28.9C set Mar 4 1950.

Also, the last subzero low temperature (Fahrenheit) in March occurred on 3/7/2003 -1°F (-18.3°C). I believe there is a shot at such cold this time around.

[vbhoutex]

Being the lazy person I am(meaning I don't want to take the time to chase the answer) I ask the question. Is this the same cold shot that is supposed to get our temps down near freezing or just below for Sunday and Monday morning? Though not unheard of freezing or close to freezing this "late" in the season in Houston is unusual.

[donsutherland1]

Dave,

Yes, it's the same cold air mass.

[Stephanie]

Right now I'm seeing some snow flurries - big flakes. This is the second shot this morning. Nothing stuck and it doesn't last long but there are alot of dark clouds being blown in by the winds and these are what is giving us our winter reminder.

March - in like a lion and boy is this appropriate for this year!

[donsutherland1]

Through 10 am, New York City has an unofficial high temperature of just 21°. During the afternoon, the mercury will likely struggle to the 20°-23° range. If it goes no higher, today will have the coldest high temperature in March since March 18, 1967, when the temperature topped out at 20°.

Which reading was more impressive?

There's actually room for debate in spite of the fact that the March 1967 reading occurred, 12 days later than today's figure. Consider the following:

Base Normals for the Dates Involved:
1951-80 Base Normal for March 18: 45.8°
1971-00 Base Normal for March 6: 46.0°
Latest 30-year period (1977-2006) for March 6: 47.0°

In short, at the time the 1967 Arctic outbeak occurred, the normal data for March 18 was about as cold as that which is now normal for March 6.

Snowcover:
March 18, 1967: 3.0"
March 6, 2007: None

March 15-17, 1967 saw a total of 5.6" of snow. On March 18, the ground remained covered by 3" of snow. In the absence of snowcover, one would expect greater modification.

All said, should the high temperature wind up around 21°, I would argue that the current Arctic outbreak is likely comparable to the 1967 one.

For what it is worth, since 1950, the following occasions saw a high temperature at or below 25° in New York City:

March 18, 1967: 20° (Base norm for date: 45.8°; Snowcover: 3.0")
March 7, 1989: 25° (Base norm for date: 47.0°; Snowcover: 3.0")
March 8, 1996: 24° (Base norm for date: 47.0°; Snowfall: 4.5")
March 9, 1996: 24° (Base norm for date: 47.0°; Snowcover at start: > 4.0")

[donsutherland1]

This morning saw some exceptionally cold readings in the northern Mid-Atlantic region, New England, and southern Canada. Minimum temperatures from select cities were:

Boston: 6° (lowest March reading since 6° on March 10, 1984)
Burlington: -7° (lowest March reading since -8° on March 4, 2003)
New York City: 11° (lowest March reading since 11° on March 3, 2003)
Philadelphia: 17° (lowest March reading since 13° on March 10, 1996)
Toronto: -8°F/-22°C (lowest March reading since -9°F/-23.0°C on March 2, 1980)
Washington, DC (DCA): 20° (lowest March reading since 20° on March 9, 2005)

The daily high temperatures are likely to be even more impressive. Moreover, some colder nightime readings are likely in some of the above cities before the cold snap finally ends after March 9.

[donsutherland1]

March 6, 2007 experienced some exceptionally cold maximum readings. Daily high temperatures for select cities were as follows:

Boston: 23° (coldest March daily maximum temperature since 23° on March 7, 1989)
Burlington: 5° (coldest March daily maximum temperature since 1° on March 7, 1989)
New York City: 21° (coldest March daily maximum temperature since 20° on March 18, 1967)
Philadelphia: 26° (coldest March daily maximum temperature since 23° on March 9, 1996)
Toronto: 10°F/-12.2°C (coldest March daily maximum temperature since 9°F/-12.8°C on March 3, 2003)
Washington, DC (DCA): 33° (coldest March daily maximum temperature since 31° on March 9, 1999)

[slartibartfast]

It's a nasty cold shot Ottawa Canada's high yesterday (march 6) was -16.8 c and the low was a good 4+ degrees colder than the record for the date looking like the night of the 8th will be pretty cold too. All things considered -16.8 deg.C in march (close to 0 F) is way colder than i like, I have bulbs up and they won't like this one bit.
Mark

[donsutherland1]

Verification:

Taking all the factors—historic, synoptic, and modeled—into consideration, I believe this short but sharp cold outbreak will likely see the temperature fall to 5° (-15°C) or below in Burlington and Toronto, 15° (-9.4°C) or below in Boston, and the teens (-7.2°C or below) in New York City and Philadelphia. There is a chance that either Toronto or Burlington sees a low temperature below 0° (-17.7°C). Boston has a chance to see a temperature below 10° (-12.2°C).

Coldest Readings:
Boston: 5°, 3/9 (coldest since 3/4/1950 when the temperature fell to 2°)
Burlington: -18°, 3/7 (coldest since 3/2/1980 when the temperature fell to -18°)
New York City: 11°, 3/6 (coldest since 3/11/2003 when the temperature fell to 11°)
Philadelphia: 16°, 3/7-8 (coldest since 3/10/1996 when the temperature fell to 13°)
Toronto: -8°F/-22.1°C, 3/6 (coldest since 3/2/1980 when the temperature fell to -9°F/-23°C)
Washington, DC (DCA): 20° (coldest since 3/9/2005 when the temperature fell to 20°)

Coldest High Temperatures:
Boston: 23°, 3/6 (coldest since 3/7/1989 when the high reached 23°)
Burlington: 5°, 3/6 (coldest since 3/7/1989 when the high reached 1°)
New York City: 21°, 3/6 (coldest since 3/18/1967 when the high reached 20°)
Philadelphia: 24°, 3/7 (coldest since 3/9/1996 when the high reached 23°)
Toronto: 10°F/-12.2°C, 3/6 (coldest since 3/3/2003 when the high reached 9°F/-12.8°C)
Washington, DC (DCA): 29°, 3/7 (coldest since 3/8/1996 when the high reached 28°)

[deltadog03]

oh ya!!! winter is not over by any stretch!

[Stephanie]

Two BEAUTIFUL weekend days so far. Yesterday's high was 62 degrees in Philadelphia and right now it's in the 50's.

[donsutherland1]

Stephanie,

After the recent cold, you deserved a few more springlike days. Even greater warmth lies ahead through at least the middle of this week.