With the trough out of the region, daytime high temperatures were warmer than those of yesterday, reaching the lower 40s inland and the mid 40s across the rest of the area. The morning temperatures were cold again, however, dropping again into the mid to upper 10s inland. With clear skies and dropping temperatures, similar low temperatures are expected again for tonight, with mid to upper 10s inland and lower to upper 20s across the rest of the area with slightly warmer temperatures for NYC. Temperatures will continue to warm up this week, with the warmest temperatures expected on Thursday when high temperatures will reach the mid 50s again.
Tomorrow's Outlook:
Tomorrow will bring warmer temperatures along with mostly sunny skies. High temperatures are expected to reach the mid 40s inland and mid to upper 40s across the rest of the area, which is approximately 5 degrees warmer than average.
Wednesday - Friday: Mild, Stormy
Partly cloudy skies are expected for Wednesday with high temperatures reaching the mid 40s across most of the area, slightly colder than those of Tuesday. Overnight, a low pressure will approach the region, with the front end of the storm bringing scattered showers on Wednesday night with temperatures steady in the mid to upper 30s inland and the upper 30s to lower 40s elsewhere. Although the area will see plain rain, places further north such the Hudson Valley and interior Connecticut are likely to see some freezing rain and sleet at the start of the storm.
With most of the precipitation staying to the north and west of the area, Thursday will bring mainly cloudy skies but with mostly dry conditions as well. Warmer high temperatures are expected, reaching the lower to mid 50s across the area. As the cold front moves through, scattered showers are expected again overnight, with temperatures dropping towards the morning as skies begin to clear and the rain moves out. Friday will bring clearing skies with temperatures dropping back into the mid 40s to lower 50s across the area.
Longer Range: A cold air mass will move in again on the weekend, with temperatures similar to those of yesterday and today expected again. Highs will reach the low to mid 40s on Saturday, with widespread upper 30s to lower 40s likely on Sunday. If mostly clear skies are observed again, widespread lows in the upper 10s to mid 20s are possible again. Temperatures will warm up again early next week as another potential storm approaches towards early-mid next week.
Monday, December 12, 2011
Sunday, December 11, 2011
Dec 11, 2011: Warmer Temperatures This Week
As a strong yet transient trough moved over the region last night, the coldest overnight lows so far this winter have been observed across the area, dropping into the mid 10s inland, lower to mid 20s in the north/west suburbs of NYC, lower 20s in southern Connecticut, and upper 20s to lower 30s in NYC, making last night the first sub-freezing low temperature in NYC this winter. Long Island generally saw lows in the 20s, although the parts of eastern Long Island which typically see the most radiational cooling dropped into the upper 10s as well. Mainly sunny skies were observed during the day with chilly temperatures, peaking in the mid to upper 30s inland and the upper 30s to lower 40s across the rest of the area.
Although the cold air mass has left the region, cold temperatures are expected again tonight. A warming trend will begin tomorrow, with highs on Tuesday once again getting to nearly 50 degrees in the immediate NYC area. Although dry conditions with mostly sunny skies will remain in place through Tuesday and slightly increased cloud cover on Wednesday, an approaching storm will bring clouds and rain back into the forecast for the late week. Although no significant rain amounts are expected, scattered showers will take place again on Thursday with warmer temperatures, passing the 50 degree mark.
Tomorrow's Outlook:
After another cold night, with temperatures dropping into the upper 10s to upper 20s across most of the area with lower 30s in NYC, warmer temperatures will return tomorrow as weak ridging continues in the eastern US. Temperatures will warm up into the lower to mid 40s inland and the mid 40s across the area, with sunny skies expected again along with light SW winds.
Tuesday - Friday: Still Warmer Than Average; Rainy Ending
Temperatures today dropped below average only for a brief time, as next week will continue the pattern of mostly above average temperatures frequent throughout the fall and the first part of this month. With mostly sunny skies, Tuesday will bring even warmer temperatures, reaching the mid 40s inland and the mid to upper 40s across the rest of the area. Although widespread lower 50s are not expected, parts of the immediate NYC area may reach 50 degrees. A slightly colder air mass will move in in on Wednesday along with partly cloudy skies, bringing slightly cooler temperatures, peaking in the mid 40s across the area with a few upper 40s in the immediate NYC area.
An intensifying low pressure will move towards the Great Lakes on Thursday, quickly moving into Canada overnight. This storm will push out the very weak cold air mass over the region, as light front end snow/sleet/freezing rain fall in parts of New England. Mostly cloudy skies are expected on Wednesday night and Thursday, and although scattered showers are expected, especially on Wednesday night, most of the time frame until Thursday evening is expected to stay mainly dry. With the area in the warmer section of the storm, temperatures will rise into the lower to mid 50s across the area on Thursday. As the storm's cold front moves through on Thursday night, temperatures will remain steady in the mid 40s to lower 50s across the area with more scattered showers moving through the area. Once the front moves through, temperatures are expected to drop; exactly when it moves is still a little uncertain, but at this time I am expecting a slight drop in temperatures on Friday morning into the upper 30s to mid 40s across most of the area, with temperatures only slightly rising on Friday afternoon to reach the mid to upper 40s across the area, potentially near the lower 50s in parts of the immediate NYC area and Long Island.
Next Weekend - Next Week: Colder, Then More Rain
A weak trough will move in behind the late week storm, bringing colder temperatures again. High temperatures are likely to drop into the lower to mid 40s across the area on Saturday and into the upper 30s to mid 40s on Sunday, with low temperatures in the 20s again across most of the area, with upper 10s possible towards NW NJ/Orange county in the colder case scenario. As should be expected with the current pattern, the ridge in the southeastern US will rebuild again as another cutoff low pressure reaches the southwestern US. Although there is uncertainty with the exact timing due to the time range, warmer temperatures are expected for the start of next week with the potential for more stormy conditions around early-mid next week. Stay tuned for more information on the longer range.
Although the cold air mass has left the region, cold temperatures are expected again tonight. A warming trend will begin tomorrow, with highs on Tuesday once again getting to nearly 50 degrees in the immediate NYC area. Although dry conditions with mostly sunny skies will remain in place through Tuesday and slightly increased cloud cover on Wednesday, an approaching storm will bring clouds and rain back into the forecast for the late week. Although no significant rain amounts are expected, scattered showers will take place again on Thursday with warmer temperatures, passing the 50 degree mark.
Tomorrow's Outlook:
After another cold night, with temperatures dropping into the upper 10s to upper 20s across most of the area with lower 30s in NYC, warmer temperatures will return tomorrow as weak ridging continues in the eastern US. Temperatures will warm up into the lower to mid 40s inland and the mid 40s across the area, with sunny skies expected again along with light SW winds.
Tuesday - Friday: Still Warmer Than Average; Rainy Ending
Temperatures today dropped below average only for a brief time, as next week will continue the pattern of mostly above average temperatures frequent throughout the fall and the first part of this month. With mostly sunny skies, Tuesday will bring even warmer temperatures, reaching the mid 40s inland and the mid to upper 40s across the rest of the area. Although widespread lower 50s are not expected, parts of the immediate NYC area may reach 50 degrees. A slightly colder air mass will move in in on Wednesday along with partly cloudy skies, bringing slightly cooler temperatures, peaking in the mid 40s across the area with a few upper 40s in the immediate NYC area.
An intensifying low pressure will move towards the Great Lakes on Thursday, quickly moving into Canada overnight. This storm will push out the very weak cold air mass over the region, as light front end snow/sleet/freezing rain fall in parts of New England. Mostly cloudy skies are expected on Wednesday night and Thursday, and although scattered showers are expected, especially on Wednesday night, most of the time frame until Thursday evening is expected to stay mainly dry. With the area in the warmer section of the storm, temperatures will rise into the lower to mid 50s across the area on Thursday. As the storm's cold front moves through on Thursday night, temperatures will remain steady in the mid 40s to lower 50s across the area with more scattered showers moving through the area. Once the front moves through, temperatures are expected to drop; exactly when it moves is still a little uncertain, but at this time I am expecting a slight drop in temperatures on Friday morning into the upper 30s to mid 40s across most of the area, with temperatures only slightly rising on Friday afternoon to reach the mid to upper 40s across the area, potentially near the lower 50s in parts of the immediate NYC area and Long Island.
Next Weekend - Next Week: Colder, Then More Rain
A weak trough will move in behind the late week storm, bringing colder temperatures again. High temperatures are likely to drop into the lower to mid 40s across the area on Saturday and into the upper 30s to mid 40s on Sunday, with low temperatures in the 20s again across most of the area, with upper 10s possible towards NW NJ/Orange county in the colder case scenario. As should be expected with the current pattern, the ridge in the southeastern US will rebuild again as another cutoff low pressure reaches the southwestern US. Although there is uncertainty with the exact timing due to the time range, warmer temperatures are expected for the start of next week with the potential for more stormy conditions around early-mid next week. Stay tuned for more information on the longer range.
Saturday, December 10, 2011
Dec 10, 2011: Cold Sunday, Warmer Week
As a weak coastal low pressure developed well offshore, today brought mostly to partly sunny skies across the area. Although temperatures inland peaked in the upper 30s, temperatures across the area peaked early in the day in the mid to upper 40s, steadily dropping throughout the day into the upper 30s to lower 40s by the afternoon. A stronger trough is currently moving towards the region, and while it will quickly move out after tonight, much colder temperatures are expected tonight into tomorrow. These temperatures do not signal that a cold pattern has established itself, however, as a ridge in the southeastern US will return once again, bringing temperatures into the upper 40s again this week and into the 50s by the late week.
Saturday's Outlook: Coldest Day So Far
With the trough moving into the region, much colder temperatures are expected for tonight. With clear skies, temperatures will drop into the mid 10s inland, lower to mid 20s in the north/west suburbs of NYC and southern Connecticut, lower to upper 20s in Long Island, and the upper 20s to lower 30s in NYC. New York City is expected to see its first sub-freezing temperature of the winter tonight.
Sunny skies will continue tomorrow with a high pressure in place, keeping the colder temperatures in place. High temperatures will reach the mid to upper 30s inland and the upper 30s to lower 40s across the area, making tomorrow the first solidly colder than average day across the area since November, although temperatures this cold will not be experienced again until after this week. In comparison, last year's December frequent featured high temperatures in the 20s to mid 30s across the area, as a result of strong blocking and a strong -NAO/-AO, a factor that is missing this year and is one of the reasons why a cold and snowy pattern is not taking place for December.
Monday - Wednesday: Slowly Warming Up
A high pressure will stay over the region through Tuesday, providing mostly sunny skies across the area in this time frame. Temperatures will warm up as well due to the trough quickly moving out of the region, and after cold temperatures again on Sunday night, with lows in the upper 10s to low 20s inland and the mid 20s to lower 30s across the rest of the area except for NYC, which would end up warmer, Monday will bring warmer high temperatures, reaching the lower to mid 40s inland and the mid to upper 40s across the rest of the area. Tuesday will warm up even more, with widespread mid to upper 40s across the area, once again warmer than average. Slightly colder temperatures will return for Wednesday, with lower to mid 40s inland and mid 40s across the rest of the area.
Thursday - Weekend: Rain And Warmer, Then Slightly Colder
By the late week, a cutoff low will be located over the southwestern US, a frequent feature this fall and early winter that is yet another reason why a colder than average pattern has failed to set up over the East. Along with a ridge in the southeastern US and nothing in Canada to keep this storm suppressed, the SW US cutoff low will move northeast, wit a low pressure developing near the central US and moving towards the Great Lakes region on Thursday. The exact timing is still uncertain, although scattered showers are likely on Wednesday night into Thursday as the majority of the precipitation stays to the north and west of the area. Temperatures are likely to warm up at least into the upper 40s to mid 50s across the area on Thursday, and depending on the timing of the storm, if it ends up as north as the latest model guidance suggests, temperatures on Thursday or Thursday night may get close to the upper 50s. The cold front will likely move through sometime around Friday, and while the timing is more uncertain, for now I am siding closer to the slower ECM than the faster GFS, which would support high temperatures reaching the lower to mid 50s across the area on Friday. A faster storm would mean highs in the 40s with colder and drier conditions for Friday, while a slower storm would mean highs returning into the upper 50s with scattered showers. Stay tuned for more information on the late week storm.
Behind this storm, colder temperatures will return, with high temperatures likely returning into the 40s, but at this time it does not appear that any strong trough would move into the region, especially with yet another southwestern US cutoff low developing. Although this is in the long range, the cutoff low indicates that there may be a storm potential for the region around early-mid next week. If there is a storm in this time frame, although snow in the northern Mid Atlantic is not impossible if the location of the storm is supportive, the pattern suggets that the Northeast would be favored over the Mid Atlantic once again for any snowstorm potential.
Longer Range: There have been recent suggestions by the models that the pattern may be changing towards a colder one by the end of December into early January. The current pattern remains locked in place, with a generally neutral EPO, slightly negative PNA, and a consistently positive NAO and AO. The stratosphere remains very cold, with the colder 500 mb departures failing to drop south of Canada into the US as blocking fails to take place. The MJO is currently located near phases 4-6, supportive of eastern warmth, but has been blocked from moving into phases 1+8, supportive of Eastern cold, showing that the pattern is not yet ready to flip into a colder and snowier one. There are signs of warming in the stratosphere starting to show up, but the response will not be automatic, as it will take time for the current pattern to break. Overall, my thoughts have not yet changed from my winter outlook; although slightly colder and snowier conditions may take place towards the very end of December, I still expect any large scale pattern change potential to wait until at least early to mid January, with the second half of the winter more likely to bring more frequent periods of cold and frozen precipitation to the NYC area.
Saturday's Outlook: Coldest Day So Far
With the trough moving into the region, much colder temperatures are expected for tonight. With clear skies, temperatures will drop into the mid 10s inland, lower to mid 20s in the north/west suburbs of NYC and southern Connecticut, lower to upper 20s in Long Island, and the upper 20s to lower 30s in NYC. New York City is expected to see its first sub-freezing temperature of the winter tonight.
Sunny skies will continue tomorrow with a high pressure in place, keeping the colder temperatures in place. High temperatures will reach the mid to upper 30s inland and the upper 30s to lower 40s across the area, making tomorrow the first solidly colder than average day across the area since November, although temperatures this cold will not be experienced again until after this week. In comparison, last year's December frequent featured high temperatures in the 20s to mid 30s across the area, as a result of strong blocking and a strong -NAO/-AO, a factor that is missing this year and is one of the reasons why a cold and snowy pattern is not taking place for December.
Monday - Wednesday: Slowly Warming Up
A high pressure will stay over the region through Tuesday, providing mostly sunny skies across the area in this time frame. Temperatures will warm up as well due to the trough quickly moving out of the region, and after cold temperatures again on Sunday night, with lows in the upper 10s to low 20s inland and the mid 20s to lower 30s across the rest of the area except for NYC, which would end up warmer, Monday will bring warmer high temperatures, reaching the lower to mid 40s inland and the mid to upper 40s across the rest of the area. Tuesday will warm up even more, with widespread mid to upper 40s across the area, once again warmer than average. Slightly colder temperatures will return for Wednesday, with lower to mid 40s inland and mid 40s across the rest of the area.
Thursday - Weekend: Rain And Warmer, Then Slightly Colder
By the late week, a cutoff low will be located over the southwestern US, a frequent feature this fall and early winter that is yet another reason why a colder than average pattern has failed to set up over the East. Along with a ridge in the southeastern US and nothing in Canada to keep this storm suppressed, the SW US cutoff low will move northeast, wit a low pressure developing near the central US and moving towards the Great Lakes region on Thursday. The exact timing is still uncertain, although scattered showers are likely on Wednesday night into Thursday as the majority of the precipitation stays to the north and west of the area. Temperatures are likely to warm up at least into the upper 40s to mid 50s across the area on Thursday, and depending on the timing of the storm, if it ends up as north as the latest model guidance suggests, temperatures on Thursday or Thursday night may get close to the upper 50s. The cold front will likely move through sometime around Friday, and while the timing is more uncertain, for now I am siding closer to the slower ECM than the faster GFS, which would support high temperatures reaching the lower to mid 50s across the area on Friday. A faster storm would mean highs in the 40s with colder and drier conditions for Friday, while a slower storm would mean highs returning into the upper 50s with scattered showers. Stay tuned for more information on the late week storm.
Behind this storm, colder temperatures will return, with high temperatures likely returning into the 40s, but at this time it does not appear that any strong trough would move into the region, especially with yet another southwestern US cutoff low developing. Although this is in the long range, the cutoff low indicates that there may be a storm potential for the region around early-mid next week. If there is a storm in this time frame, although snow in the northern Mid Atlantic is not impossible if the location of the storm is supportive, the pattern suggets that the Northeast would be favored over the Mid Atlantic once again for any snowstorm potential.
Longer Range: There have been recent suggestions by the models that the pattern may be changing towards a colder one by the end of December into early January. The current pattern remains locked in place, with a generally neutral EPO, slightly negative PNA, and a consistently positive NAO and AO. The stratosphere remains very cold, with the colder 500 mb departures failing to drop south of Canada into the US as blocking fails to take place. The MJO is currently located near phases 4-6, supportive of eastern warmth, but has been blocked from moving into phases 1+8, supportive of Eastern cold, showing that the pattern is not yet ready to flip into a colder and snowier one. There are signs of warming in the stratosphere starting to show up, but the response will not be automatic, as it will take time for the current pattern to break. Overall, my thoughts have not yet changed from my winter outlook; although slightly colder and snowier conditions may take place towards the very end of December, I still expect any large scale pattern change potential to wait until at least early to mid January, with the second half of the winter more likely to bring more frequent periods of cold and frozen precipitation to the NYC area.
Dec 7-8, 2011 Storm Review
After a large ridge had been stuck over the eastern United States, bringing well above average temperatures across the area, a developing low pressure brought heavy rain across the area, with over 2 inches of rain observed. Although the impacts of this storm were not unusual, the forecasting of the storm was unusually difficult, as the model guidance kept showing a variety of solutions and then changing the position of the storm, failing to lock onto a single idea until only 24 hours away from the storm.
Storm Impact:
Occasional showers were observed across the area throughout Tuesday, 12/6, bringing light rain amounts across the area. On Wednesday afternoon, a more organized low pressure began to develop near North Carolina, with more widespread heavy rain developing across the region. Through Wednesday evening, most of the area ended up with at least 1/2 to 1 inch with higher amounts west of NYC. By Wednesday night, however, as the low pressure moved up the coast and severe thunderstorms in the southern Mid Atlantic moved into the NYC area, more widespread heavy rain was observed, as can be seen with the radar image to the left at 10 PM Wednesday.
The rain began to mix with snow in the interior parts of the area after at least 12 AM, with the mix spreading as far southeast as nearly the north/west suburbs of NYC, where some areas reported mixed precipitation. As the storm was in the process of phasing and rapidly intensifying, it also moved very quickly, moving from eastern Long Island to the eastern tip of Maine in just about 6 hours. As a result of the storm's fast motion, the precipitation also moved out quickly, ending across the area by at least 3 AM.
Observed rain totals mostly ended up within the 2 to 2.5 inches range, locally up to 3 inches, across northern NJ, SE NY and southern Connecticut, near to slightly below 2 inches in NYC, and between 1.25 and 2 inches across most of Long Island. Snow accumulations in the area and across the region ended up lower than expected, with light accumulations in the interior parts of the area. Parts of West Passaic, Sussex and Orange counties observed 1 to 2 inches of snow. The wind aspect of the storm was more surprising, as there were indications that windy conditions would be observed but not as strong as they ended up; widespread wind gusts of 50 to 60 mph were observed in NYC and Long Island, with a peak gust of 69 mph in Westhampton, NY.
Forecasts For Storm: Poor Model Performance
There are several models frequently used for making forecasts; the GFS, NAM, ECMWF, GGEM and UKMET models. The models are not always correct, and are used as guidance for making forecasts instead of directly used as the forecasts. Typically, models begin to converge on a single solution for a storm at least 72-84 hours (3-4 days) away from the main event. In this case, however, the models had issues with handling the set up at 500 millibars until the last minute, resulting in poor model performance for the storm.
The coastal low developed as a result of a 500 mb low becoming negatively tilted while moving from the south central US into the Northeast and towards Canada while phasing and rapidly intensifying. The models were unable to figure out where the 500 mb low would end up until the short range, resulting in a variety of solutions with each model. Up until 66-72 hours away from the storm, the models did not even show the correct overall set up for the storm, resulting in a variety of solutions ranging from a large storm on Wednesday morning to no storm to a northern Mid Atlantic Thursday snowstorm. By that time, approximately 3 days away from the actual event, the models corrected the set up at 500 mb to represent a scenario closer to the actual one, but the new model guidance solutions were still incorrect as they showed a more separated 500 mb low well to the west of its actual position, which resulted in the models bringing in more cold air after a Tuesday cold front, placing initial cold air in place, and later on brought a snowstorm to the NYC area. This was the most evident with the NAM model, which brought heavy snow near NYC with a few of its runs.
Approximately 54 hours way from the storm, the models once again changed the position of the 500 mb low, now showing it more attached to the cold front and more amplified, which meant that the cold front on Tuesday would not be able to cross the area, preventing cold air from moving in ahead of the Wednesday storm, but that the cold air would gradually enter the storm as it develops and moves up the coast. This was closer to the actual scenario that happened with the storm, but the issue at that time was that the 500 mb low was still not in the correct position, and would not end up correct until nearly 24 hours away from the actual event. As a result, throughout the 1-2 day range prior to the storm, the models continued to adjust their solutions towards a further west storm, first showing a snowstorm near NYC, then showing rain to accumulating snow, followed by rain to a rain/snow mix. Finally, when a final solution has been reached, only a little over 1 day prior to the storm, it finally appeared that there would be plain rain from the storm in NYC with as much as 2-3 inches.
The winds with this storm were not expected to be as strong as they were, although there were plenty of indications to suggest that there would be a brief period of strong wind gusts as the storm came to an end. The models did not show very strong wind gusts, generally falling in the 30-40 mph range, although there was a tight pressure gradient in the back end of the storm on the models, which suggested that combined with the heavy rain falling at that time, the potential existed for brief yet strong wind gusts. With my final update during the storm, I went higher than the models, calling for gusts locally up to 45 mph, but even this call ended up too low, as actual gusts ended up in the 50-65 mph range across most of Long Island, and between 40-50 mph in NYC.
Storm Impact:
The rain began to mix with snow in the interior parts of the area after at least 12 AM, with the mix spreading as far southeast as nearly the north/west suburbs of NYC, where some areas reported mixed precipitation. As the storm was in the process of phasing and rapidly intensifying, it also moved very quickly, moving from eastern Long Island to the eastern tip of Maine in just about 6 hours. As a result of the storm's fast motion, the precipitation also moved out quickly, ending across the area by at least 3 AM.
Observed rain totals mostly ended up within the 2 to 2.5 inches range, locally up to 3 inches, across northern NJ, SE NY and southern Connecticut, near to slightly below 2 inches in NYC, and between 1.25 and 2 inches across most of Long Island. Snow accumulations in the area and across the region ended up lower than expected, with light accumulations in the interior parts of the area. Parts of West Passaic, Sussex and Orange counties observed 1 to 2 inches of snow. The wind aspect of the storm was more surprising, as there were indications that windy conditions would be observed but not as strong as they ended up; widespread wind gusts of 50 to 60 mph were observed in NYC and Long Island, with a peak gust of 69 mph in Westhampton, NY.
Forecasts For Storm: Poor Model Performance
There are several models frequently used for making forecasts; the GFS, NAM, ECMWF, GGEM and UKMET models. The models are not always correct, and are used as guidance for making forecasts instead of directly used as the forecasts. Typically, models begin to converge on a single solution for a storm at least 72-84 hours (3-4 days) away from the main event. In this case, however, the models had issues with handling the set up at 500 millibars until the last minute, resulting in poor model performance for the storm.
The coastal low developed as a result of a 500 mb low becoming negatively tilted while moving from the south central US into the Northeast and towards Canada while phasing and rapidly intensifying. The models were unable to figure out where the 500 mb low would end up until the short range, resulting in a variety of solutions with each model. Up until 66-72 hours away from the storm, the models did not even show the correct overall set up for the storm, resulting in a variety of solutions ranging from a large storm on Wednesday morning to no storm to a northern Mid Atlantic Thursday snowstorm. By that time, approximately 3 days away from the actual event, the models corrected the set up at 500 mb to represent a scenario closer to the actual one, but the new model guidance solutions were still incorrect as they showed a more separated 500 mb low well to the west of its actual position, which resulted in the models bringing in more cold air after a Tuesday cold front, placing initial cold air in place, and later on brought a snowstorm to the NYC area. This was the most evident with the NAM model, which brought heavy snow near NYC with a few of its runs.
Approximately 54 hours way from the storm, the models once again changed the position of the 500 mb low, now showing it more attached to the cold front and more amplified, which meant that the cold front on Tuesday would not be able to cross the area, preventing cold air from moving in ahead of the Wednesday storm, but that the cold air would gradually enter the storm as it develops and moves up the coast. This was closer to the actual scenario that happened with the storm, but the issue at that time was that the 500 mb low was still not in the correct position, and would not end up correct until nearly 24 hours away from the actual event. As a result, throughout the 1-2 day range prior to the storm, the models continued to adjust their solutions towards a further west storm, first showing a snowstorm near NYC, then showing rain to accumulating snow, followed by rain to a rain/snow mix. Finally, when a final solution has been reached, only a little over 1 day prior to the storm, it finally appeared that there would be plain rain from the storm in NYC with as much as 2-3 inches.
The winds with this storm were not expected to be as strong as they were, although there were plenty of indications to suggest that there would be a brief period of strong wind gusts as the storm came to an end. The models did not show very strong wind gusts, generally falling in the 30-40 mph range, although there was a tight pressure gradient in the back end of the storm on the models, which suggested that combined with the heavy rain falling at that time, the potential existed for brief yet strong wind gusts. With my final update during the storm, I went higher than the models, calling for gusts locally up to 45 mph, but even this call ended up too low, as actual gusts ended up in the 50-65 mph range across most of Long Island, and between 40-50 mph in NYC.
12/10 Noon Update
6:00 PM:
- The final winter outlook, posted last Saturday, has been slightly revised, fixing a few errors and adding a few small notes, although the expectations in the outlook have not been changed. An updated outlook will be posted on January 1.
- The poll for this winter's snow in NYC, found to the right below the "NYC Area Weather Alerts" section, has been extended through Wednesday.
- A summary for Wednesday night's storm will be posted later this evening, along with a discussion on the 7-10 day outlook.
- The final winter outlook, posted last Saturday, has been slightly revised, fixing a few errors and adding a few small notes, although the expectations in the outlook have not been changed. An updated outlook will be posted on January 1.
- The poll for this winter's snow in NYC, found to the right below the "NYC Area Weather Alerts" section, has been extended through Wednesday.
- A summary for Wednesday night's storm will be posted later this evening, along with a discussion on the 7-10 day outlook.
Friday, December 9, 2011
Dec 9, 2011: Cold Weekend Ahead
Note: The 5-Day Forecast page has been updated for NYC and further west, and will be updated for Long Island and southern CT starting on Saturday. Instead of a brief review on Wednesday's storm, a more detailed overview of the storm, especially focusing on the forecasting of the storm, will be posted on Saturday evening before the daily evening update.
------------------------------------------------------------
Forecast Overview for Week Ahead:
Weekend - Partly cloudy skies are expected on Saturday with colder temperatures, dropping into the upper 30s to lower 40s inland and the lower to mid 40s across the rest of the area. As a high pressure moves in, clear skies will move in for Saturday night and Sunday with much colder temperatures, dropping as low as the mid 10s inland and the lower to mid 20s north and west of NYC and in southern Connecticut. Parts of New York City will drop below freezing for the first time this winter, reaching the upper 20s to lower 30s. Sunday will bring colder temperatures with sunny skies, peaking in the mid to upper 30s inland and the upper 30s to lower 40s across the rest of the area.
Monday - Wednesday: The first half of next week will bring average temperatures for the area, a change from the long lasting spell of above average temperatures since October, but this is not yet a change in the pattern consisting of frequent ridging in the East, as tomorrow's discussion will explain in more details. Temperatures on Monday through Wednesday are expected to reach the lower to mid 40s across the area, with the immediate NYC area potentially reaching the upper 40s on Monday and/or Tuesday. Overnight lows will remain chilly, dropping into the lower to upper 20s inland and the mid 20s to lower 30s across the rest of the area. Mostly sunny skies are expected on Monday and Tuesday, with slightly increased cloud cover for Wednesday.
Thursday - Friday: As weak ridging returns into the East, yet another cutoff low is expected to develop near the southwestern US. With no strong push of cold air from Canada or anything to keep the storm suppressed, a low pressure will likely develop near the central US. Whether it moves due east to bring snow to New England or northeast towards the Great Lakes remains to be seen, but with the set up in place, the storm is not expected to bring snow to the NYC area, bringing rain again, with New England the favored area for the snow potential. Temperatures will likely end up warmer on Thursday and Friday, potentially passing 50 degrees on one of these days. Stay tuned for more information on the late week storm potential.
------------------------------------------------------------
Forecast Overview for Week Ahead:
Weekend - Partly cloudy skies are expected on Saturday with colder temperatures, dropping into the upper 30s to lower 40s inland and the lower to mid 40s across the rest of the area. As a high pressure moves in, clear skies will move in for Saturday night and Sunday with much colder temperatures, dropping as low as the mid 10s inland and the lower to mid 20s north and west of NYC and in southern Connecticut. Parts of New York City will drop below freezing for the first time this winter, reaching the upper 20s to lower 30s. Sunday will bring colder temperatures with sunny skies, peaking in the mid to upper 30s inland and the upper 30s to lower 40s across the rest of the area.
Monday - Wednesday: The first half of next week will bring average temperatures for the area, a change from the long lasting spell of above average temperatures since October, but this is not yet a change in the pattern consisting of frequent ridging in the East, as tomorrow's discussion will explain in more details. Temperatures on Monday through Wednesday are expected to reach the lower to mid 40s across the area, with the immediate NYC area potentially reaching the upper 40s on Monday and/or Tuesday. Overnight lows will remain chilly, dropping into the lower to upper 20s inland and the mid 20s to lower 30s across the rest of the area. Mostly sunny skies are expected on Monday and Tuesday, with slightly increased cloud cover for Wednesday.
Thursday - Friday: As weak ridging returns into the East, yet another cutoff low is expected to develop near the southwestern US. With no strong push of cold air from Canada or anything to keep the storm suppressed, a low pressure will likely develop near the central US. Whether it moves due east to bring snow to New England or northeast towards the Great Lakes remains to be seen, but with the set up in place, the storm is not expected to bring snow to the NYC area, bringing rain again, with New England the favored area for the snow potential. Temperatures will likely end up warmer on Thursday and Friday, potentially passing 50 degrees on one of these days. Stay tuned for more information on the late week storm potential.
Thursday, December 8, 2011
**No Update Posted 12/8/11**
Due to some technical difficulties, I was unable to post an update tonight. Tomorrow evening, I will post an overview of yesterday's storm, including the strong wind gusts and heavy rain amounts, including a longer range forecast.
Subscribe to:
Posts (Atom)