bluewave

This October seems to be a continuation of the same general 2019 pattern. Above normal temperatures in the East with cooler temperatures over portions of the West.

Imagine how hot it would have been with this pattern in July instead of September.

12z today was the first time all the models converged on a common solution. Now we just have to wait and see what type of shorter term adjustments develop next few days. Euro forecast courtesy of eweather https://twitter.com/Eweather13?ref_src=twsrc^google|twcamp^serp|twgr^author

Very extreme pattern right now. Developing powerful East Coast Storm and Upper Plains snowstorm. Followed by the typhoon recurve impacts on the pattern for the next few weeks.

Right now the convection is suppressed near the dateline. Root for that to change if you want to see more of an El Niño atmospheric response. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

Very confused look to the Pacific right now. This may be our first time in October with Niño 4 this warm and Niño 1+2 so cool. The latest weekly SST departures are: Niño 4 Niño 3.4 Niño 3 Niño 1+2 1.0oC 0.5oC 0.3oC -0.6oC

This has to be one of the oddest looking cutoff lows in a while. Notice how high the 500 mb heights are when the low first closes off. Can’t remember the last time there was a low closing off over our area at close to 580 dm. This unusual setup may be part of the reason the models have been so volatile from run to run.

Looks like the warm spots can sneak in another 80 degree day today with enough breaks of sun.

We are fortunate that lower end DO to D2 drought conditions have been the worst we have experienced here since 2002. The rest of the country hasn’t been so lucky with extended periods of D3 and D4 drought. So occasionally we have to put up with low soil moisture like the last month. This is mainly a concern for landscape and agricultural interests rather water supply managers. Great animation showing how lucky we have been compared to other parts of the country since 2002: https://twitter.com/akrherz Simple lapse of the CONUS portion of the US Drought Monitor since 2000. Please feel free to use however you wish. Raw mp4 here: https://mesonet.agron.iastate.edu/pickup/usdm/2000_2019_lapse.mp4

I can’t remember such extreme PNA swings this time of year before. So it’s no surprise that the models will be showing big run to run changes with storm details.

This is what happens with such extreme wavelength changes over a short period of time. Just look at the volatility in the PNA since the end of September. The models can only do so much.

First 60+ degree temperature drop at SMQ in under 72 hours during October. Although the record only goes back to 1999, this drop probably couldn’t be matched over a longer period. Stations around the region with much longer periods of record experienced their all-time 24 hr October temperature drops this week. The high a few days ago at SMQ was 95 between hours with the low today of 33. So an actual drop of 62 degrees.

This was the driest September on record for Islip on Long Island. Our entire area was added to abnormally dry on the last few drought monitor updates. It was the the northeast extension of the flash drought which enveloped the East over the last month. Pockets of extreme drought developed over the Southeast this week. The drought coupled with the warming trend allowed for so many October all-time record highs across the East this week. It was mostly a surface layer event around here affecting the vegetation and soil moisture. Luckily, we have not experienced sustained more extreme drought conditions here since the mid 1990’s into early 2000’s. Those were more serious and dropped the water supply levels to the point were usage restrictions were necessary.

It would be nice if the Euro is correct about the stalled front merging with a coastal storm this week. Rain amounts like this would go a long way toward ending the drought conditions around here.

October 5th is the earliest this decade that NYC reached 45 degrees or colder. First/Last Summary for NY CITY CENTRAL PARK, NY Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. Year Last Value First Value Difference Minimum 04-23 (2011) 10-08 (2012) 150 Mean 05-07 10-18 164 Maximum 05-25 (2013) 10-27 (2011) 186 2012 04-30 (2012) 43 10-08 (2012) 44 160 2016 05-16 (2016) 43 10-15 (2016) 45 151 2015 04-25 (2015) 38 10-17 (2015) 42 174 2017 05-13 (2017) 45 10-17 (2017) 42 156 2018 04-30 (2018) 44 10-18 (2018) 42 170 2014 04-30 (2014) 41 10-19 (2014) 44 171 2010 05-13 (2010) 43 10-23 (2010) 44 162 2013 05-25 (2013) 45 10-23 (2013) 45 150 2011 04-23 (2011) 43 10-27 (2011) 38 186 2019 05-15 (2019) 44 - - -

The IOD and SOI are currently in a mode that we usually see with a more robust El Niño pattern. So maybe the SST’s become more Niño-like back toward Niño 3.4 and 4. The current split has cold near South America and warm west. Right now the 500 mb pattern is a blend of Niño and Niña features.

Unusual combinations of Pacific SST departures and atmospheric indices have become the new normal. As has been the case in recent years, how they interact together will determine our weather.

That was the driest late July into mid-September on record for JFK. Only .36 of rain. I can still remember many of the local ponds drying up. Time Series Summary for JFK INTL AP, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Precipitation Jul 29 to Sep 16 Missing Count 1 1995-09-16 0.36 0 2 1972-09-16 1.14 0 3 1985-09-16 2.17 0 4 2005-09-16 2.36 0 5 1973-09-16 2.53 0

It was the latest 95 degree day at JFK by 3 weeks. The heat was so extreme for this late in the season, that JFK beat the previous highest October record of 90 in 2007 by a full 5 degrees.

Our first 40 degree temperature drop in 24 hours during October. The high of 96 between hours makes it an even 40 degrees. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=169&network=NJ_ASOS&zstation=EWR&hours=24&month=oct&dir=cool&dpi=100&_fmt=png

All the winters this decade have presented new combinations of competing extremes. The timing of the general pattern progressions have sometimes been correctly forecast in advance. But the nature and magnitude of the extremes have often been a surprise.

Portions of the Southeast upgraded to extreme drought today.

The IOD is just 1 piece of the puzzle going forward this year. How will the IOD interact with the ENSO? + IOD events usually occur with with El Niño’s. We currently also have a more Nino-like -SOI. There is a very strong +PMM and +NPM. While ENSO is currently neutral, some warming has been occurring in recent weeks. What if any influence will it have in the MJO? What about the stratosphere and phase of the NAO?

Looks like we have the strongest +IOD since the 97-98 super El Niño. http://www.bom.gov.au/climate/enso/ The very strong positive Indian Ocean Dipole event persists, characterised by cooler waters to the northwest of Australia and warmer waters further west. Values of the IOD index over the past fortnight have strengthened, and the latest value of +1.76 °C is the strongest positive weekly value since at least 2001.

Amazing to have the warmest October average temperature, monthly maximum temperature, and highest minimum temperature only 2 years apart. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Oct Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2017 63.8 0 2 2007 63.5 0 3 1971 63.1 0 4 1990 62.4 0 5 1984 62.2 0 Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Oct Click column heading to sort ascending, click again to sort descending. Rank Year Highest Max Temperature Missing Count 1 2019 96 29 2 1941 93 0 3 1949 92 0 4 1959 91 0 5 1939 90 0 - 1938 90 0 Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Oct Click column heading to sort ascending, click again to sort descending. Rank Year Highest Min Temperature Missing Count 1 2017 73 0 2 1959 71 0 3 2018 70 0 - 2005 70 0 - 1990 70 0 - 1986 70 0 - 1954 70 0