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August 2019 General Discussions & Observations Thread


bluewave
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The Middle Atlantic and southern New England region concluded a very warm July. In New York City, the mean temperature was 79.5°, which was 3.0° above normal. That was tied with 1983 as New York City's 11th warmest July on record. The last time July was warmer was in 2013 when July had a monthly average temperature of 79.8°.

Such warmth has typically been followed by a warmer than normal August. Since 1869, New York City had 20 prior cases with a July mean temperature of 79.0° or above. The August mean temperature for those cases was 76.4° with a standard deviation of 2.2°. However, in the 11 cases in which the July average temperature was 79.5° or above, the August mean temperature was also 76.4°, but the standard deviation was just 1.2°. July 2019 falls into the latter warmer category. This data suggests that simply based on historical outcomes, August 2019 will very likely be warmer than normal in the region. Those historical outcomes are supported by teleconnections data and by at least some of the longer-range guidance.

The historic heat that smashed high temperature records in much of western Europe and then Scandinavia will continue to affect Iceland and Greenland for another day or two. Near-record to possibly record surface mass balance (SMB) loss could occur during that period. Already, rapid losses in SMB have been occurring.

Professor Jason Box, ice climatologist at the Geological Survey of Denmark and Greenland observed, "On the Arctic Circle, southwestern Greenland ice sheet, 2019 melt to-date is 1.3x that of the previous record melt at that location in 2010. 1.4x that in 2012."

High temperatures in Greenland included Ilulissat: 66°; Kangerlussuaq: 72°; Kulusuk: 59°; Narsarsuaq: 66°; Nuuk: 50°; and, Thule: 54°.

Anchorage has concluded its warmest month on record following its warmest June on record. The July 2019 mean temperature was 65.1°. That easily surpassed the old record of 62.7°, which was recorded in July 2016.

The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was +0.4°C for the week centered around July 24. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.27°C and the ENSO Region 3.4 anomaly has averaged +0.40°C. Neutral-warm ENSO conditions are now evolving. There is considerable uncertainty about the ENSO evolution later this summer into the fall. Some of the guidance shows the development of neutral-cool ENSO conditions.

The SOI was +3.14 today.

Today, the preliminary Arctic Oscillation (AO) figure was -1.647. A general tendency for blocking could persist through mid-August with perhaps some occasional fluctuations to positive values. This persistence of blocking will promote a generally warm or perhaps very warm remainder of summer.

Since 1950, there was only a single year that saw the AO average -1.000 or below in May and -0.500 or below in June (the preliminary June 2019 average was -0.665): 1993. 1993 featured much above normal readings in the East during the late summer (August 15-September 15 period) and predominantly cooler than normal readings across the western third of the nation during much of the summer.

In addition, since 1950, there have been four prior cases when the AO averaged -0.500 or below in both June and July: 1957, 1958, 1993, and 2009. In three (75%) of those cases, August wound up warmer than normal. August 1993 was the warmest case. The mean anomaly from those cases suggests that the Middle Atlantic and southern New England areas could be approximately 0.5° to 1.5° above normal overall during August.

Overall, 1993 remains the base case for the pattern that should generally prevail from mid-August to mid-September. Currently, the CFSv2 suggests that a warmer than normal pattern could develop around mid-August.

On July 30, the MJO was in Phase 3 at an amplitude of 0.434 (RMM). The July 29-adjusted amplitude was 0.600.

August will likely be warmer than normal across the Middle Atlantic and southern New England areas. The CFSv2, which understated the degree of warmth in July, suggests near normal conditions in August. However, based on the preponderance of date, it is likely an outlier. The potential exists for some cooler than normal to near normal readings from the middle of the first week of August into the latter portion of the second week of August. However, no notably cold readings appear likely. Afterward, warmer anomalies should return. The warmest anomalies relative to normal will likely occur during the second half of the month. Those warm anomalies will likely persist into at least the start of September.

Finally, On July 30, Arctic sea ice extent was 5.998 million square kilometers (JAXA). That broke the daily minimum record of 6.132 million square kilometers, which was set in 2012. It is also the earliest figure under 6.000 million square kilometers. The previous earliest figure occurred on August 3, 2012 when Arctic sea ice extent was 5.911 million square kilometers. Based on the average statistical decline and on sensitivity analysis, it is likely that Arctic sea ice extent will fall below 4.000 million square kilometers at its minimum for only the second time on record.

Some probabilities from the sensitivity analysis:

4.500 million square kilometers or below: 84%
4.000 million square kilometers or below: 63%
3.500 million square kilometers or below: 36%
 

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The next 8 days are averaging 78degs., or 2degs. AN.

GFS 0Z, has a .hurricane linger near Florida for 4 days, instead of turning before reaching the area.    Aug. 10 to 14.

72.8* here at 6am.   78.8* by 10am.   80.0* by 10:45am.

Don't worry.   All is forgiven and the 06Z Run has nothing, no development at all.     If the CMC ain;t got it, forget it!

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16 hours ago, donsutherland1 said:

The Middle Atlantic and southern New England region concluded a very warm July. In New York City, the mean temperature was 79.5°, which was 3.0° above normal. That was tied with 1983 as New York City's 11th warmest July on record. The last time July was warmer was in 2013 when July had a monthly average temperature of 79.8°.

Such warmth has typically been followed by a warmer than normal August. Since 1869, New York City had 20 prior cases with a July mean temperature of 79.0° or above. The August mean temperature for those cases was 76.4° with a standard deviation of 2.2°. However, in the 11 cases in which the July average temperature was 79.5° or above, the August mean temperature was also 76.4°, but the standard deviation was just 1.2°. July 2019 falls into the latter warmer category. This data suggests that simply based on historical outcomes, August 2019 will very likely be warmer than normal in the region. Those historical outcomes are supported by teleconnections data and by at least some of the longer-range guidance.

The historic heat that smashed high temperature records in much of western Europe and then Scandinavia will continue to affect Iceland and Greenland for another day or two. Near-record to possibly record surface mass balance (SMB) loss could occur during that period. Already, rapid losses in SMB have been occurring.

Professor Jason Box, ice climatologist at the Geological Survey of Denmark and Greenland observed, "On the Arctic Circle, southwestern Greenland ice sheet, 2019 melt to-date is 1.3x that of the previous record melt at that location in 2010. 1.4x that in 2012."

High temperatures in Greenland included Ilulissat: 66°; Kangerlussuaq: 72°; Kulusuk: 59°; Narsarsuaq: 66°; Nuuk: 50°; and, Thule: 54°.

Anchorage has concluded its warmest month on record following its warmest June on record. The July 2019 mean temperature was 65.1°. That easily surpassed the old record of 62.7°, which was recorded in July 2016.

The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was +0.4°C for the week centered around July 24. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.27°C and the ENSO Region 3.4 anomaly has averaged +0.40°C. Neutral-warm ENSO conditions are now evolving. There is considerable uncertainty about the ENSO evolution later this summer into the fall. Some of the guidance shows the development of neutral-cool ENSO conditions.

The SOI was +3.14 today.

Today, the preliminary Arctic Oscillation (AO) figure was -1.647. A general tendency for blocking could persist through mid-August with perhaps some occasional fluctuations to positive values. This persistence of blocking will promote a generally warm or perhaps very warm remainder of summer.

Since 1950, there was only a single year that saw the AO average -1.000 or below in May and -0.500 or below in June (the preliminary June 2019 average was -0.665): 1993. 1993 featured much above normal readings in the East during the late summer (August 15-September 15 period) and predominantly cooler than normal readings across the western third of the nation during much of the summer.

In addition, since 1950, there have been four prior cases when the AO averaged -0.500 or below in both June and July: 1957, 1958, 1993, and 2009. In three (75%) of those cases, August wound up warmer than normal. August 1993 was the warmest case. The mean anomaly from those cases suggests that the Middle Atlantic and southern New England areas could be approximately 0.5° to 1.5° above normal overall during August.

Overall, 1993 remains the base case for the pattern that should generally prevail from mid-August to mid-September. Currently, the CFSv2 suggests that a warmer than normal pattern could develop around mid-August.

On July 30, the MJO was in Phase 3 at an amplitude of 0.434 (RMM). The July 29-adjusted amplitude was 0.600.

August will likely be warmer than normal across the Middle Atlantic and southern New England areas. The CFSv2, which understated the degree of warmth in July, suggests near normal conditions in August. However, based on the preponderance of date, it is likely an outlier. The potential exists for some cooler than normal to near normal readings from the middle of the first week of August into the latter portion of the second week of August. However, no notably cold readings appear likely. Afterward, warmer anomalies should return. The warmest anomalies relative to normal will likely occur during the second half of the month. Those warm anomalies will likely persist into at least the start of September.

Finally, On July 30, Arctic sea ice extent was 5.998 million square kilometers (JAXA). That broke the daily minimum record of 6.132 million square kilometers, which was set in 2012. It is also the earliest figure under 6.000 million square kilometers. The previous earliest figure occurred on August 3, 2012 when Arctic sea ice extent was 5.911 million square kilometers. Based on the average statistical decline and on sensitivity analysis, it is likely that Arctic sea ice extent will fall below 4.000 million square kilometers at its minimum for only the second time on record.

Some probabilities from the sensitivity analysis:

4.500 million square kilometers or below: 84%
4.000 million square kilometers or below: 63%
3.500 million square kilometers or below: 36%
 

Don, looks like Boston had their hottest July on record?  78.5 avg temp?

 

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1 hour ago, rclab said:

The way things are trending, it’s like saying, tonight there is a 100% chance of darkness.

Agreed, the whole base state of the lower troposphere keeps going up. There will still be cold in winter relative to averages in the mid latitudes though as the jet stream in forced south. One thing is certain, more extremes

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Depending on what guidance you look at, the western half of NJ and points west could have a fun day tomorrow tracking thunderstorms. There is some shortwave energy coming together to help enhance lift. Return flow develops early in the morning, but southeasterly winds will keep coastal areas milder (but more humid than today), while we watch anvil cirrus blow in from that activity.

Saturday will see thunderstorms become a bit more widespread in the Northeast, largely due to increasing humidity/return flow and seabreezes developing. The city will probably miss out again while parts of LI and the interior cash in on scattered PM activity.

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1 hour ago, bluewave said:

First, the Euro has a shot of 90 degree heat and 75 degree dewpoints. Then another round of convection ahead of the cold front. The wild card may be the strength of the WAR slowing the front down. Could lead to more training convection along the front if it stalls. We’ll have to wait and see how much cool actually makes it to the East Coast. Longer range cool downs have been getting milder the closer we get recently. But perhaps the coming big -NAO drop will be good for at least a few more comfortable days eventually.

 

 

given the well above normal SST's off the coast and the resultant stronger WAR I'm wary of any big or long lasting cooldown within 100 miles of the east coast.

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On ‎7‎/‎31‎/‎2019 at 8:03 PM, donsutherland1 said:

The Middle Atlantic and southern New England region concluded a very warm July. In New York City, the mean temperature was 79.5°, which was 3.0° above normal. That was tied with 1983 as New York City's 11th warmest July on record. The last time July was warmer was in 2013 when July had a monthly average temperature of 79.8°.

Such warmth has typically been followed by a warmer than normal August. Since 1869, New York City had 20 prior cases with a July mean temperature of 79.0° or above. The August mean temperature for those cases was 76.4° with a standard deviation of 2.2°. However, in the 11 cases in which the July average temperature was 79.5° or above, the August mean temperature was also 76.4°, but the standard deviation was just 1.2°. July 2019 falls into the latter warmer category. This data suggests that simply based on historical outcomes, August 2019 will very likely be warmer than normal in the region. Those historical outcomes are supported by teleconnections data and by at least some of the longer-range guidance.

The historic heat that smashed high temperature records in much of western Europe and then Scandinavia will continue to affect Iceland and Greenland for another day or two. Near-record to possibly record surface mass balance (SMB) loss could occur during that period. Already, rapid losses in SMB have been occurring.

Professor Jason Box, ice climatologist at the Geological Survey of Denmark and Greenland observed, "On the Arctic Circle, southwestern Greenland ice sheet, 2019 melt to-date is 1.3x that of the previous record melt at that location in 2010. 1.4x that in 2012."

High temperatures in Greenland included Ilulissat: 66°; Kangerlussuaq: 72°; Kulusuk: 59°; Narsarsuaq: 66°; Nuuk: 50°; and, Thule: 54°.

Anchorage has concluded its warmest month on record following its warmest June on record. The July 2019 mean temperature was 65.1°. That easily surpassed the old record of 62.7°, which was recorded in July 2016.

The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was +0.4°C for the week centered around July 24. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.27°C and the ENSO Region 3.4 anomaly has averaged +0.40°C. Neutral-warm ENSO conditions are now evolving. There is considerable uncertainty about the ENSO evolution later this summer into the fall. Some of the guidance shows the development of neutral-cool ENSO conditions.

The SOI was +3.14 today.

Today, the preliminary Arctic Oscillation (AO) figure was -1.647. A general tendency for blocking could persist through mid-August with perhaps some occasional fluctuations to positive values. This persistence of blocking will promote a generally warm or perhaps very warm remainder of summer.

Since 1950, there was only a single year that saw the AO average -1.000 or below in May and -0.500 or below in June (the preliminary June 2019 average was -0.665): 1993. 1993 featured much above normal readings in the East during the late summer (August 15-September 15 period) and predominantly cooler than normal readings across the western third of the nation during much of the summer.

In addition, since 1950, there have been four prior cases when the AO averaged -0.500 or below in both June and July: 1957, 1958, 1993, and 2009. In three (75%) of those cases, August wound up warmer than normal. August 1993 was the warmest case. The mean anomaly from those cases suggests that the Middle Atlantic and southern New England areas could be approximately 0.5° to 1.5° above normal overall during August.

Overall, 1993 remains the base case for the pattern that should generally prevail from mid-August to mid-September. Currently, the CFSv2 suggests that a warmer than normal pattern could develop around mid-August.

On July 30, the MJO was in Phase 3 at an amplitude of 0.434 (RMM). The July 29-adjusted amplitude was 0.600.

August will likely be warmer than normal across the Middle Atlantic and southern New England areas. The CFSv2, which understated the degree of warmth in July, suggests near normal conditions in August. However, based on the preponderance of date, it is likely an outlier. The potential exists for some cooler than normal to near normal readings from the middle of the first week of August into the latter portion of the second week of August. However, no notably cold readings appear likely. Afterward, warmer anomalies should return. The warmest anomalies relative to normal will likely occur during the second half of the month. Those warm anomalies will likely persist into at least the start of September.

Finally, On July 30, Arctic sea ice extent was 5.998 million square kilometers (JAXA). That broke the daily minimum record of 6.132 million square kilometers, which was set in 2012. It is also the earliest figure under 6.000 million square kilometers. The previous earliest figure occurred on August 3, 2012 when Arctic sea ice extent was 5.911 million square kilometers. Based on the average statistical decline and on sensitivity analysis, it is likely that Arctic sea ice extent will fall below 4.000 million square kilometers at its minimum for only the second time on record.

Some probabilities from the sensitivity analysis:

4.500 million square kilometers or below: 84%
4.000 million square kilometers or below: 63%
3.500 million square kilometers or below: 36%
 

Another example of Central Park erroneously being used as a legitimate proxy for New York City.

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1 hour ago, bluewave said:

he biggest NAO drop of the summer looks like it will allow the trough to return to the Northeast day 6-10.

@bluewave   I thought that the correlation to NAO blocking in the summer months was warmer along the East Coast? 

I see Don S mentionuing this , but maybe it is more so the -AO he is referring to.   

Is this event forecasted to happen based simply on the extreme drop in the NAO ?  The EPS is rather bullish for cooler weather as you mentioned later next week. 

Looks like this -NAO dive is a consequence from the heat displaced from the recent all time records certain sections of Europe. 

I believe Judah Cohen posted on that . 

  

 

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3 hours ago, gravitylover said:

^^ Bump that thing out for a few more days. The wife and I are spending the weekend on Fire Island without our kids next weekend, first we've done without since my heart attack last December, so cool is ok but wet is no good. 

No greater medicinal joy that time spent with a good and loving partner. No greater sadness than once filled but now empty arms. Yours will remain happily filled for many decades to come. As always....

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