1ST GUESS COMING FOR JAN 14-15 EVENT
-45 this morning in Yellowstone Natl park in far northwest WY this morning.
LEFT MAP is MIN temps RIGHT MAP show the MAX temps
FROM JAN 5
http://www.meteo.psu.edu/~gadomski/MAXMIN_NA/t-7.gif
FROM JAN 11
note the change in max and MIN temps over in western Canada
JAN 11 http://www.meteo.psu.edu/~gadomski/MAXMIN_NA/t0.gif
One of the characteristics of the El Niño winter is an enhanced or stronger than normal STJ- or subtropical jet. This can have a significant impact and manifests itself with forecasting problems in several different ways.
When you have a moderate or strong El Niño he subtropical jet becomes so strong that it into overpowering the PJ (polar jet) and as a result you can often get a zonal or west to east flow across the CONUS with all the Arctic air bottled up north of US Canada border. This will we saw in much of November and Decmber and when you had a four taxes situated over the Bering Sea... this sort of synoptic pattern in the general sense is more likely to be dominant and not.
Another characteristic of course it is that any sort of cold air outbreaks ends up coming in weaker than forecasted and / or does NOT lock in. I can this will we saw in the first week of December when the El Nino was moderate. This is NOT however a problem in weak El Ninos events.
Still another SEASONAL and common characteristic of Moderate El Niño winters featiures systems which are supposed to be fairly strong and take northerly tracts end up getting suppressed or shunted Eastern Northeast because of the progressive and stronger than normal subtropical jet.
Sometimes you will see in a El Niño winter where systems coming out of the Gulf of Mexico are depicted by the medium-range Models as developing into a major winter storm for the Midwest or the East Coast. Then as the possible event gets closer and closer the tracks end of shifting further to the south and east. Sometimes this can work for the benefit of those wanting snow and ice in the big cities of Northeast or Midwest. A classic case of this would be a track shown several days outgoing up the Appalachian Mountains and then as we get closer and closer to the possible event the track is shifted to the south and east so that a time event actually occurs the system is tracking through southeastern Virginia.
But on the other hand this can also work against you . When you have a very strong Arctic outbreak like we are currently experiencing and will be over the next several days the cold air plunges deep into the Plains and the eastern half the US. But without that any high latitude Blocking over eastern Canada / Greenland sometimes the cold Arctic HIGHs will drop all the way into Texas and Oklahoma and then track east across the Tennessee Valley. ( liek we are going to see over the next 4-5 days).
Because the flow is so progressive the enhanced STJ any sort of Low pressure development activity stays flat along the Gulf Coast and its tracks E or ENE tracking off the southeast coast of US... which can often result in winter weather lovers in the Midwest and Northeast nashing their teeth in frustration saying how the hell is Alabama getting more snow then Pennsylvania?
The morning weather map shows the Arctic front has driven into northern Texas and east and Oklahoma but it has NOT yet reached the Midwest b/c of the power of the the Southeast Ridge. Earlier there was some speculation that the significant shortwave coming out of the Southwest would become a Plains a snowstorm with heavy snows developing from Denver towards Minneapolis or maybe northern Wisconsin. However I argued several days ago here and in some other forums that such a forecast was bogus because of the seasonal trend one must taken consideration when you're dealing with weak and moderate El Niño winters.
In addition the model data has been very clear that the shortwave coming out of the Southwest US is going to be "suppressed " or crushed d by the strong Polar Jet dropping out of Canada. It is a GOLDEN RULE OF SYNOPTIC FORECASTNG and one that should be well-known ....when you have a s/w which is getting crushed or weakened it is very hard for the system to track to the NE or NNE. I will be issuing a FIRST GUESS for the Midwest and New England event shortly -- it's hard to believe that this point in the winter we have had so little activity in eastern half the US that this is the first one of the season I am doing here on January 12.
From what appears to me right now it looks like locations such as Des Moines Iowa Rockford or knowing at Chicago will see the best nose probably over to Detroit and then across Buffalo Syracuse perhaps Albany and then north New England. The tricky as portion of this is going to be eastern New England. No doubt that the initial precipitation over Boston will be generally rain at the start but once the 850 Low tracks closer it may shift to the south and the thermal gradient associated with this 850 Low is going to be very impressive. Additionally once the system was off the New England coast to may be some wraparound snows b/c of the comma head moisture into east New England which could produce some decent snows as the system is pulling away.
I also want to announce that I now have access to the European weekly forecasts that run out to 30 days or four weeks. These come out every Thursday evening or early Friday morning. And the latest information on these models are showing very cold temperatures the last week of January the first week of February over the entire Northeast quadrant of the country which means not only New England and Atlantic also the how Valley in eastern Great Lakes as well. That being said there is No support for the idea that Jan 15-Feb 15 are going to place in the top 10 coldest 30 days period in the last 50 years.
I am concerned that the potential exists for some sort of wave or Low pressure to develop over the Gulf/ Delta because the fairly s/w that develops a negative tils over the Mississippi Valley around January 20 --21. This is an showing up on some of the European and GFS ensembles over last few days so I think thee is enough support in ensembles that it registers as a RISK for the first POSSIBLE winter storm for the East Coast of the season. Right now it appears that the cold air is going to be around at the start but the Polar Let configurations dont look good. The lack of blocking over Northeastern Canada and Greenland is going to be a problem. You see if the Arctic high pressure systems continued to drop Deep into the Plains states then track across the TN VALLEY then off the SE coast then thigns are goping to have to occur JUST right to keep the cold air in place over the NE CONUS. We could end up seeing an event where the first cold High slides off the East Coast.... the Low develops between this high and the next Arctic HIGH that dropa out of central Canada and as result we end up going from snow to rain over the big cities of the Northeast. If we only had some high Latitude blocking to keep the cold air in place -- such as a Grenland Block OR a 50/50 Low then things would look a lot more promising and that may yet develop.
LEFT MAP is MIN temps RIGHT MAP show the MAX temps
FROM JAN 5
http://www.meteo.psu.edu/~gadomski/MAXMIN_NA/t-7.gif
FROM JAN 11
note the change in max and MIN temps over in western Canada
JAN 11 http://www.meteo.psu.edu/~gadomski/MAXMIN_NA/t0.gif
One of the characteristics of the El Niño winter is an enhanced or stronger than normal STJ- or subtropical jet. This can have a significant impact and manifests itself with forecasting problems in several different ways.
When you have a moderate or strong El Niño he subtropical jet becomes so strong that it into overpowering the PJ (polar jet) and as a result you can often get a zonal or west to east flow across the CONUS with all the Arctic air bottled up north of US Canada border. This will we saw in much of November and Decmber and when you had a four taxes situated over the Bering Sea... this sort of synoptic pattern in the general sense is more likely to be dominant and not.
Another characteristic of course it is that any sort of cold air outbreaks ends up coming in weaker than forecasted and / or does NOT lock in. I can this will we saw in the first week of December when the El Nino was moderate. This is NOT however a problem in weak El Ninos events.
Still another SEASONAL and common characteristic of Moderate El Niño winters featiures systems which are supposed to be fairly strong and take northerly tracts end up getting suppressed or shunted Eastern Northeast because of the progressive and stronger than normal subtropical jet.
Sometimes you will see in a El Niño winter where systems coming out of the Gulf of Mexico are depicted by the medium-range Models as developing into a major winter storm for the Midwest or the East Coast. Then as the possible event gets closer and closer the tracks end of shifting further to the south and east. Sometimes this can work for the benefit of those wanting snow and ice in the big cities of Northeast or Midwest. A classic case of this would be a track shown several days outgoing up the Appalachian Mountains and then as we get closer and closer to the possible event the track is shifted to the south and east so that a time event actually occurs the system is tracking through southeastern Virginia.
But on the other hand this can also work against you . When you have a very strong Arctic outbreak like we are currently experiencing and will be over the next several days the cold air plunges deep into the Plains and the eastern half the US. But without that any high latitude Blocking over eastern Canada / Greenland sometimes the cold Arctic HIGHs will drop all the way into Texas and Oklahoma and then track east across the Tennessee Valley. ( liek we are going to see over the next 4-5 days).
Because the flow is so progressive the enhanced STJ any sort of Low pressure development activity stays flat along the Gulf Coast and its tracks E or ENE tracking off the southeast coast of US... which can often result in winter weather lovers in the Midwest and Northeast nashing their teeth in frustration saying how the hell is Alabama getting more snow then Pennsylvania?
The morning weather map shows the Arctic front has driven into northern Texas and east and Oklahoma but it has NOT yet reached the Midwest b/c of the power of the the Southeast Ridge. Earlier there was some speculation that the significant shortwave coming out of the Southwest would become a Plains a snowstorm with heavy snows developing from Denver towards Minneapolis or maybe northern Wisconsin. However I argued several days ago here and in some other forums that such a forecast was bogus because of the seasonal trend one must taken consideration when you're dealing with weak and moderate El Niño winters.
In addition the model data has been very clear that the shortwave coming out of the Southwest US is going to be "suppressed " or crushed d by the strong Polar Jet dropping out of Canada. It is a GOLDEN RULE OF SYNOPTIC FORECASTNG and one that should be well-known ....when you have a s/w which is getting crushed or weakened it is very hard for the system to track to the NE or NNE. I will be issuing a FIRST GUESS for the Midwest and New England event shortly -- it's hard to believe that this point in the winter we have had so little activity in eastern half the US that this is the first one of the season I am doing here on January 12.
From what appears to me right now it looks like locations such as Des Moines Iowa Rockford or knowing at Chicago will see the best nose probably over to Detroit and then across Buffalo Syracuse perhaps Albany and then north New England. The tricky as portion of this is going to be eastern New England. No doubt that the initial precipitation over Boston will be generally rain at the start but once the 850 Low tracks closer it may shift to the south and the thermal gradient associated with this 850 Low is going to be very impressive. Additionally once the system was off the New England coast to may be some wraparound snows b/c of the comma head moisture into east New England which could produce some decent snows as the system is pulling away.
I also want to announce that I now have access to the European weekly forecasts that run out to 30 days or four weeks. These come out every Thursday evening or early Friday morning. And the latest information on these models are showing very cold temperatures the last week of January the first week of February over the entire Northeast quadrant of the country which means not only New England and Atlantic also the how Valley in eastern Great Lakes as well. That being said there is No support for the idea that Jan 15-Feb 15 are going to place in the top 10 coldest 30 days period in the last 50 years.
I am concerned that the potential exists for some sort of wave or Low pressure to develop over the Gulf/ Delta because the fairly s/w that develops a negative tils over the Mississippi Valley around January 20 --21. This is an showing up on some of the European and GFS ensembles over last few days so I think thee is enough support in ensembles that it registers as a RISK for the first POSSIBLE winter storm for the East Coast of the season. Right now it appears that the cold air is going to be around at the start but the Polar Let configurations dont look good. The lack of blocking over Northeastern Canada and Greenland is going to be a problem. You see if the Arctic high pressure systems continued to drop Deep into the Plains states then track across the TN VALLEY then off the SE coast then thigns are goping to have to occur JUST right to keep the cold air in place over the NE CONUS. We could end up seeing an event where the first cold High slides off the East Coast.... the Low develops between this high and the next Arctic HIGH that dropa out of central Canada and as result we end up going from snow to rain over the big cities of the Northeast. If we only had some high Latitude blocking to keep the cold air in place -- such as a Grenland Block OR a 50/50 Low then things would look a lot more promising and that may yet develop.
posted by DT @ 1/12/2007 12:25:00 PM
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