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January 2011 Thoughts: Area of Warmth Could Be Somewhat Limited


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Ottawa Blizzard

-20C is too easy for Ottawa

-30C as registered by Subzero is certainly more impressive!

and you didn't even have to wait for the 'Arctic Air' to truly arrive :lol:

barnes corner made it to -30F!

PUBLIC INFORMATION STATEMENT

SPOTTER REPORTS

NATIONAL WEATHER SERVICE BUFFALO NY

830 AM EST MON JAN 17 2011

COLD TEMPERATURES WERE OBSERVED ACROSS WESTERN NEW YORK THIS MORNING.

MORNING LOW TEMPERATURES WERE THE COLDEST TEMPERATURES SO FAR THIS YEAR.

THE FOLLOWING ARE UNOFFICIAL LOW TEMPERATURES TAKEN THIS MORNING ACROSS

WESTERN NEW YORK. APPRECIATION IS EXTENDED TO COCORAHS...COOPERATIVE

OBSERVERS...SKYWARN SPOTTERS AND MEDIA FOR THESE REPORTS. THIS SUMMARY

IS ALSO AVAILABLE ON OUR HOME PAGE AT WEATHER.GOV/BUFFALO

*********************MAXIMUM WIND SPEED*********************

LOCATION MORNING LOW COMMENTS

TEMPERATURE

NEW YORK

...CHAUTAUQUA COUNTY...

DUNKIRK -2 ASOS

...ERIE COUNTY...

CLARENCE CENTER -9 SPOTTER

WALES -8 COOP

ELMA -7 COCORAHS

WILLIAMSVILLE -3 NWS EMPLOYEE

BUFFALO -1 ASOS

...GENESEE COUNTY...

PAVILION -8 COOP

...JEFFERSON COUNTY...

WATERTOWN -24 ASOS

...LEWIS COUNTY...

BARNES CORNERS -30 SPOTTER

HIGHMARKET -22 COOP

...LIVINGSTON COUNTY...

AVON -12 COOP

...MONROE COUNTY...

ROCHESTER -7 ASOS

...NIAGARA COUNTY...

NORTH TONAWANDA -7 COCORAHS

NIAGARA FALLS -6 ASOS

...ONTARIO COUNTY...

GENEVA -5 COOP

...OSWEGO COUNTY...

FULTON -12 ASOS

PALERMO -6 COCORAHS

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Three quick thoughts:

1. The -20°C minimum temperature has now verified for Ottawa. The coldest period will likely be January 22-25 +/- 1 day. During that timeframe, there is potential for the temperature to remain below 0°F for a whole day.

2. The idea of at least one single digit low temperature (°F) in Philadelphia and New York City looks good for the January 22-24 timeframe. Such cold should follow a light to perhaps moderate snowfall.

3. Although the AO will very likely be positive toward the end of the month, the PNA+ setup should preclude much above normal readings as the calendar moves into February. An EPO- ridge should be rebuilding during the first week in February. Afterward, if past severe blocking episodes in December are representative, the AO should be returning negative probably late in the first week in February or just afterward. The possibility of a severely negative AO (-3 or below) exists, but that might not occur until mid-February.

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Three quick thoughts:

1. The -20°C minimum temperature has now verified for Ottawa. The coldest period will likely be January 22-25 +/- 1 day. During that timeframe, there is potential for the temperature to remain below 0°F for a whole day.

2. The idea of at least one single digit low temperature (°F) in Philadelphia and New York City looks good for the January 22-24 timeframe. Such cold should follow a light to perhaps moderate snowfall.

3. Although the AO will very likely be positive toward the end of the month, the PNA+ setup should preclude much above normal readings as the calendar moves into February. An EPO- ridge should be rebuilding during the first week in February. Afterward, if past severe blocking episodes in December are representative, the AO should be returning negative probably late in the first week in February or just afterward. The possibility of a severely negative AO (-3 or below) exists, but that might not occur until mid-February.

At the time the AO goes negative, will the PNA remain positive and will the EPO remain negative? If so, what are the implications for the CONUS?

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The current positive reading is likely to be short-lived. The period to which I'm referring toward the end of the month will likely see 7-10 days of positive readings before new AO blocking develops (unless, of course, I'm wrong).

I don't think you will be wrong. The global GFS values may be a tad too low with the -AO values this next week.

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Three quick thoughts:

1. The -20°C minimum temperature has now verified for Ottawa. The coldest period will likely be January 22-25 +/- 1 day. During that timeframe, there is potential for the temperature to remain below 0°F for a whole day.

2. The idea of at least one single digit low temperature (°F) in Philadelphia and New York City looks good for the January 22-24 timeframe. Such cold should follow a light to perhaps moderate snowfall.

3. Although the AO will very likely be positive toward the end of the month, the PNA+ setup should preclude much above normal readings as the calendar moves into February. An EPO- ridge should be rebuilding during the first week in February. Afterward, if past severe blocking episodes in December are representative, the AO should be returning negative probably late in the first week in February or just afterward. The possibility of a severely negative AO (-3 or below) exists, but that might not occur until mid-February.

Don, how is the snow potential for ottawa looking, in your opinion? Tuesday-Wednesday looks to be a bust, although it would be nice if we could squeek out 2-4". Is the first half of February looking cold for us, i.e. for Winterlude?

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A PNA+, EPO-, AO- regime would be one that would have the potential for below to much below normal readings in the eastern half to two-thirds of the nation.

Do you see any hope for the NW? I do know our November blast came when the AO first began to crash. If the AO goes positive and then plunges again, do you think that would be an opportunity for us?

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Yeah, he must be out in a very rural area. It's actually quite nice out. Cold, but barely any wind.

I'm around Trim and Innes... Pretty much rural, right at the edge of Orleans. I took a pic of the thermometer with my iPhone...if only I knew how to post it here. I bottomed out at -30.

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Do you think a "plunge" is in the cards (Don, or anyone)?

It's too soon to tell if it will plunge, but a turn down that should take it, IMO, to -3 or lower is probably more likely than not. Already, the GFS ensembles show the downward trend starting around ~ February 1. That start date could vary a little, but I don't believe the positive regime currently modeled toward the end of January will last more than 14 days. 7-10 days is probably a more likely duration.

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Do you see any hope for the NW? I do know our November blast came when the AO first began to crash. If the AO goes positive and then plunges again, do you think that would be an opportunity for us?

Until the PNA+ regime ends, I don't believe there will be much prospect of wintry weather in the Pacific Northwest. Hopefully, the PNA will decline in the near-term, but right now there is very little support for such an outcome. I am quite concerned that the current PNA+ regime that has established itself could be persistent. The rest of January looks warmer than normal. Hopefully, things will look better afterward.

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A PNA+, EPO-, AO- regime would be one that would have the potential for below to much below normal readings in the eastern half to two-thirds of the nation.

Do you think such a regime is in the cards for sometime in February?

Would the weather effects of such a regime be affected by the presence of a positive or negative NAO? If so, how?

Thanks in advance and keep up the great work.

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Do you think such a regime is in the cards for sometime in February?

I suspect that the biggest wildcard is the PNA. Will it head negative or will it hold positive. Odds may lean slightly toward the latter situation even during the current La Niña/PDO- cycle.

Would the weather effects of such a regime be affected by the presence of a positive or negative NAO? If so, how?

The NAO could well have an impact on temperatures and storm tracks. Later in February, a negative NAO would, in general, become increasingly important for the Mid-Atlantic states' snowfall prospects.

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Do you see any hope for the NW? I do know our November blast came when the AO first began to crash. If the AO goes positive and then plunges again, do you think that would be an opportunity for us?

The Pacific Northwest's fate will ride on the PNA. During the 11/20-29/2010 cold spell (peak was 11/21-24 with a mean temperature nearly 18° below normal in Seattle), the PNA was negative. During the 11/20-29 period, the PNA averaged -1.461. During the height of the cold (11/21-24), the PNA averaged -1.904. With that PNA setup, the cold air was focused on the Pacific Northwest. If the PNA is positive, the focus of the cold anomalies will be farther east (Plains to East Coast) depending on the other synoptic factors involved.

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I suspect that the biggest wildcard is the PNA. Will it head negative or will it hold positive. Odds may lean slightly toward the latter situation even during the current La Niña/PDO- cycle.

The NAO could well have an impact on temperatures and storm tracks. Later in February, a negative NAO would, in general, become increasingly important for the Mid-Atlantic states' snowfall prospects.

Don, Im wondering if this index combo might lead towards a big Feb event like some la ninas are known for (a la Feb 2006) or whether that would hold off until March (a la March 1956) if it happens at all. That kind of event would please the majority of people who've missed out on the last couple of storms.

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Looking at the ensemble means and the GFS forecast this evening, it looks like the AAO, AO and NAO are all going definatley toward positive in early Feb. Am I misreading? If not, any prognostications at to whether its a continued or short-lived +.

Any input appreciated (?????)!

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The Pacific Northwest's fate will ride on the PNA. During the 11/20-29/2010 cold spell (peak was 11/21-24 with a mean temperature nearly 18° below normal in Seattle), the PNA was negative. During the 11/20-29 period, the PNA averaged -1.461. During the height of the cold (11/21-24), the PNA averaged -1.904. With that PNA setup, the cold air was focused on the Pacific Northwest. If the PNA is positive, the focus of the cold anomalies will be farther east (Plains to East Coast) depending on the other synoptic factors involved.

I just don't get it. Why on Earth is the PNA wanting to be positive with this strong of a La Nina? This winter appeared to have everything going for it and now it looks like we may get robbed right to the end. The East is getting all of the good breaks lately. Sometimes I just hate this place.

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Dang,

I look at Raleigh WX, the GFS and the ensembles, and get three differing ideas on where the AAO, AO, and NAO are going for the next few days to couple of weeks --> up (yes?), neutral (probably/maybe?), down (perhaps, but doesn't seem to fit the scale?).

Anyone with knowledge want to clarify (please).

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I just don't get it. Why on Earth is the PNA wanting to be positive with this strong of a La Nina? This winter appeared to have everything going for it and now it looks like we may get robbed right to the end. The East is getting all of the good breaks lately. Sometimes I just hate this place.

It's the MJO that's forcing the +PNA, with strong tropical convection nearing the dateline.

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SnowWizard and all people from the Pac NW...I feel your pain, sorta....it's like having an El Niño and torching this way during winter. Yes, the MJO is the driving force of this upcoming +PNA period. In a borderline strong Niña, with such a high SOI for that many consecutive months and west based to boot, having tropical forcing around the dateline is sort of a miracle, especially considering that it might be relatively a long duration event. But I think it won't last past the first 10 days of February, and a -PNA pattern might come back with a vengeance... But we have to take into account that high latitude ridging might also rebuild strongly at the time the +PNA pattern subside. If it's Pacific high latitude based ridging (-EPO), Pac NW will be golden...but if it's West based NAO (east based shouldn't be a problem, I think)... well, try again next year :(.

In the mean time, a very Niñoish pattern will settle for the whole south and east coast, with very nice opportunities of wintry weather along the aforementioned areas. Watch out for a big one.

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Several quick thoughts on the AO:

1. Given past experience with historic severe to extreme December blocking episodes, the three ensemble members suggesting that the AO will likely peak at +3 to +4 near the end of January or around February 1 are probably overdone. I suspect a +1 to +2 peak is more likely.

2. The ensemble consensus that the AO will go positive for a time is reasonable. I suspect the AO+ regime will likely last 7-10 days.

3. Relying on past experience with the historic blocking cases, I suspect that the AO will begin to trend downward beginning sometime during the first week in February. The two ensemble members showing an aggressive decline prior to February 1 are likely premature. However, a gradual decline could accelerate afterward.

Things to look for:

1. The most aggressive ensemble members will scale back their forecast for the peak positive AO.

2. A growing number of ensemble members will indicate a decline in the AO sometime during the first week in February.

Already, if one animates RaleighWx's Northern Hemisphere 500 mb height anomalies, the 12z GFS run has moved somewhat more toward a less aggressive AO+ peak and a slow recovery in the AO blocking vs. the 6z run in the last frames of the animation.

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In yesterday's discussion on the AO, I noted:

1. Given past experience with historic severe to extreme December blocking episodes, the three ensemble members suggesting that the AO will likely peak at +3 to +4 near the end of January or around February 1 are probably overdone. I suspect a +1 to +2 peak is more likely.

2. The ensemble consensus that the AO will go positive for a time is reasonable. I suspect the AO+ regime will likely last 7-10 days.

3. Relying on past experience with the historic blocking cases, I suspect that the AO will begin to trend downward beginning sometime during the first week in February. The two ensemble members showing an aggressive decline prior to February 1 are likely premature. However, a gradual decline could accelerate afterward.

Today's ensemble guidance shows two members bringing the AO to a peak of +3 to +4 (1 member less than yesterday). The remainder point to a peak in the +1 to +2 range. More importantly, almost all of them have the AO falling near or just after February 1. All said, there is a little more support this morning for a redevelopment of an AO- regime in February. Such an outcome would be consistent with prior cases with severe to extreme December AO blocking.

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