bluewave

A wild card moving forward may be all that warm water over the Eastern IO. MJO 3 is associated with a trough over the East this time of year. During the summer this pattern can produce a trough over the Midwest or Great Lakes. But the Atlantic and Gulf record SST’s support a strong WAR pattern. How far west this ridge is able to build will determine whether we have a 0 to +2 summer or warmer. In any event, looks like it could be wet and humid if such a pattern sets up. So maybe warmer summer minimums and clouds preventing more frequent 100 days of 2010 to 2013. Be interesting to see how things turn out.

The EPS is cool and wet for us until further notice. The -EPO/-NAO will get some help from a strong +PNA ridge out west. So the trough stays in place over the East.

Yeah, we have become used to at least +2 to +3 monthly departures and top 10 warmest finishes. But Islip was able to set a record low temperature the other day. Record lows have become few and far between. The lack of an April monthly high temperature of 70 or warmer really stands out so far. If this can hold, then it would be the lowest April high temperature on record at Newark. NYC is currently at 3 lowest. This tells you how strong the blocking influence on on pattern is this month. 4/17 30 in 2020 30 in 2005 30 in 1971 Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Apr Click column heading to sort ascending, click again to sort descending. Rank Year Highest Max Temperature Missing Count 1 2020 69 12 2 1940 70 0 3 1931 71 0 4 1966 72 0 - 1937 72 0 5 1998 74 0 - 1997 74 0 - 1988 74 0 Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Apr Click column heading to sort ascending, click again to sort descending. Rank Year Highest Max Temperature Missing Count 1 1874 64 0 - 1873 64 0 2 1940 67 0 - 1875 67 0 3 2020 68 12 - 1883 68 0 4 1884 69 0 - 1876 69 0 5 1916 70 0

Yeah, a combination of the slowing AMOC and stronger +NAO. https://noc.ac.uk/news/changes-ocean-circulation-cause-largest-freshening-event-ne-atlantic-120-years Changes in ocean circulation cause largest freshening event in NE Atlantic in 120 years Posted: 29 January 2020 A change in the routing of fresh water coming from the Arctic has led to a remarkable reduction in salinity in the North Atlantic Ocean west of the UK, according to research published this week in Nature Communications. An enormous area between UK and Iceland had record-breaking low salinity at the surface by 2016 – the lowest since records began in 1895. Lead author, Professor Penny Holliday from the National Oceanography Centre (NOC), said “This is the first time the physical process causing this reduction in salinity has been identified. This helps us build a picture of the factors influencing environmental conditions, including looking to see whether existing models can reproduce it.” “We care about the environmental conditions because they can impact ecosystem health, and knowing how things are changing is a key step towards managing our marine resources sustainably.” Led by NOC scientists and co-authored by the Scottish Association for Marine Science (SAMS), this study shows that in 2012 to 2016 unusual wind patterns forced Arctic fresh water carried by the Labrador Current away from the eastern North American continental shelf. The cold, fresh water was directed into the North Atlantic Current which carried it towards the UK and Iceland. An unexpected and rapid decrease in salinity, known as the ‘North Atlantic fresh blob’ developed while the region was also cooling and developing a feature known as the ‘North Atlantic cold blob’. Recent research has suggested that the ‘cold blob’ was caused by a combination of high heat loss from the ocean surface to the atmosphere and by a slow-down of a large-scale system of ocean currents carrying heat northwards, referred to the Atlantic Ocean Atlantic Meridional Overturning Circulation (AMOC). This new study emphasises the importance of changes in the local currents of the subpolar region, and in particular in the pathways of fresh water from the Arctic, in changing the environmental conditions of the North-East Atlantic Ocean. The change in the pathway of the Arctic water carried by the Labrador Current has implications for the North West Atlantic too; the regions that were receiving the cold, fresh and nutrient-rich Arctic water before 2012 include the Gulf of Maine, which has experienced damaging marine heatwaves and high salinity in recent years. Professor Penny Holliday explains “Changes in environmental conditions in the eastern North Atlantic and in the Gulf of Maine have recently been attributed to changes in the AMOC and local heat loss. This new study shows the importance of winter wind patterns and local ocean circulation changes in determining the fate of Arctic waters and the subsequent environmental change.” These findings used long-term data sets from on-going research expeditions in the North Atlantic, such as along the Extended Ellett Line, or the OSNAP programme. This research forms part of the Blue-Action project, which aims to understand and simulate links between the Arctic and the global climate system, and the Arctic’s role in generating weather patterns associated with hazardous conditions and climatic extremes. Latest News Upcoming Events Events Calendar Marine Life Talks Interviews with NOC Spokespersons News Archive Events Archive NOC logo

EPS maintains the trough over the Northeast for the remainder of the month. Persistent -NAO and ridge out west. Be interesting to see if we can sneak in a stray 70 degree day for April.

Yeah, March and April are typically the snowiest months of the year in the Rockies and Plains.

Small pockets of cold and snow in a sea of warmth.

Remarkable how that tiny cold departure over the Rockies allowed for snowiest season on record in Boulder.

The strong -NAO/-EPO pattern was the only thing able to suppress the SE Ridge this month. The record winter warmth into March pushed the Atlantic and Gulf SST’s to all-time record warmth for this time of year. We have seen in recent years how persistent these spring -NAO patterns have been.

Only 1 winter month with a -NAO since 2012 vs 8 in the spring. 2012 1.17 0.42 1.27 0.47 -0.91 -2.53 -1.32 -0.98 -0.59 -2.06 -0.58 0.17 2013 0.35 -0.45 -1.61 0.69 0.57 0.52 0.67 0.97 0.24 -1.28 0.90 0.95 2014 0.29 1.34 0.80 0.31 -0.92 -0.97 0.18 -1.68 1.62 -1.27 0.68 1.86 2015 1.79 1.32 1.45 0.73 0.15 -0.07 -3.18 -0.76 -0.65 0.44 1.74 2.24 2016 0.12 1.58 0.73 0.38 -0.77 -0.43 -1.76 -1.65 0.61 0.41 -0.16 0.48 2017 0.48 1.00 0.74 1.73 -1.91 0.05 1.26 -1.10 -0.61 0.19 -0.00 0.88 2018 1.44 1.58 -0.93 1.24 2.12 1.09 1.39 1.97 1.67 0.93 -0.11 0.61 2019 0.59 0.29 1.23 0.47 -2.62 -1.09 -1.43 -1.17 -0.16 -1.41 0.28 1.20 2020 1.34 1.26 1.01

Our next freeze after this weekend is coming up around the middle of next week. Pretty impressive to see a piece of the TPV drop into Northern New England this late in the season.

Maybe we can sneak in a 70 degree reading on one of the warmer days. But it’s tough to get to reach 80 with the persistent -NAO pattern. We get the high over SE Canada with clouds, showers, and onshore flow on our milder days.

It’s tough to get an accumulation at the coast so late in the season. But 2014 was the 3rd latest measurable snowfall on record for us. The trough locked in over the Great Lakes from the winter through the summer that year. First/Last Summary for NEWARK LIBERTY INTL AP, NJ 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 1986 04-23 (1986) 0.1 12-09 (1986) 0.9 229 1983 04-19 (1983) 4.1 11-25 (1983) 1.2 219 2014 04-16 (2014) 0.1 11-26 (2014) 1.4 223

A piece of the TPV actually drops as far south as Maine. It’s believable with such a strong -EPO/-NAO.

Looks like ISP tied the record low of 30 this morning. Several record lows to our west last few days. Very strong -EPO/-NAO pattern continues. 17 Apr 7:56 am 39 22 50 33 W 8 10.00 FEW250 30.20 1026.3 30.31 39 30 4/17 30 in 2005 30 in 1971 31 in 1966

Freeze potential tonight outside NYC. Looks like it will be a little later than usual since 2010. ISLIP KISP GFS MOS GUIDANCE 4/16/2020 1200 UTC DT /APR 16/APR 17 /APR 18 /APR 19 HR 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12 N/X 31 49 44 53 36 Frost/Freeze Summary for ISLIP-LI MACARTHUR AP, 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 Season Length Minimum 03-27 (2010) 10-13 (2012) 176 Mean 04-08 10-30 204 Maximum 04-25 (2015) 11-14 (2016) 224 2019 04-02 (2019) 26 11-04 (2019) 32 215 2018 04-11 (2018) 26 10-22 (2018) 32 193 2017 03-30 (2017) 32 11-10 (2017) 26 224 2016 04-10 (2016) 32 11-14 (2016) 32 217 2015 04-25 (2015) 32 10-19 (2015) 29 176 2014 04-16 (2014) 32 11-08 (2014) 31 205 2013 04-07 (2013) 31 10-26 (2013) 32 201 2012 04-06 (2012) 32 10-13 (2012) 32 189 2011 04-08 (2011) 32 10-31 (2011) 30 205 2010 03-27 (2010) 28 11-02 (2010) 30 219

70 degrees. So a degree warmer than the first half of April. Monthly Highest Max Temperature for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 2020 70 62 80 69 M M M M M M M M 80

Their mid March-April seems to be a version of what the Midwest experienced in March 2012.

The wild card is how long the -NAO persists. The -NAO has suppressed the record heat to our south during recent springs. All-time April record heat has occurred around the GOM this month.

Yeah, this has been a very impressive -NAO/-EPO pattern for April. Maybe we can sneak in a stray 70 over the next 10 days. But we won’t see any 80 degree heat until this pattern relaxes.

There were also areas north of NYC that had HWW conditions. CWOP ...Dutchess County... Bannerman Island 66 1045 AM 4/13 WXFLOW Beacon 60 1020 AM 4/13 NYSM 1039 AM NON-TSTM WND GST 1 S MAMARONECK 40.92N 73.73W 04/13/2020 M60 MPH ANZ335 NY WXFLOW LARCHMONT HARBOR WXFLOW STATION...ELEVATION 40 FEET. CWOP ...Westchester County... Tappan Zee Light 14 68 1051 AM 4/13 WXFLOW Bridgeport Airport 61 1153 AM 4/13 ASOS

You have to remember that the the open spaces like airports and shorelines are better representations of the actual peak wind gusts than your local neighborhood Davis sensor. Notice how many reports of downed trees there were across the entire area that weren’t near airports or the shoreline. This is telling you that the peak winds in local neighborhoods were realized near the treetop level. So the trees we’re blocking many home sensors from measuring the actual neighborhood peak gusts.

The most reports of 60mph+ gusts in the OKX zones were over Suffolk. This is where the models had indicated than the strongest LLJ in our local area would occur. The 82 mph gust along the Jersey Shore was with the well defined gravity wave. ...SUFFOLK COUNTY... ORIENT 68 404 PM 4/13 TRAINED SPOTTER ORIENT 66 231 PM 4/13 CWOP STONY BROOK 63 319 PM 4/13 CWOP ISLIP AIRPORT 61 147 PM 4/13 ASOS ISLIP AIRPORT 61 147 PM 4/13 ASOS 1 S BROOKHAVEN 60 146 PM 4/13 MESONET 1 E BELLVIEW BEACH 60 149 PM 4/13 WXFLOW EATONS NECK 60 232 PM 4/13 WXFLOW STONY BROOK 58 243 PM 4/13 CWOP ORIENT 57 245 PM 4/13 CWOP GREAT SOUTH BAY 57 133 PM 4/13 WXFLOW WEST GILGO BEACH 56 131 PM 4/13 CWOP SINAI HARBOR 56 1218 PM 4/13 WXFLOW MECOX BAY 55 205 PM 4/13 WXFLOW BLUE POINT 55 346 PM 4/13 WXFLOW FISHERS ISLAND AIRPO 55 1255 PM 4/13 WXFLOW FARMINGDALE AIRPORT 55 200 PM 4/13 ASOS FIRE ISLAND CG 54 143 PM 4/13 WXFLOW SHIRLEY AIRPORT 54 155 PM 4/13 ASOS NAPEAGUE 53 309 PM 4/13 WXFLOW WESTHAMPTON AIRPORT 52 206 PM 4/13 ASOS WEST ISLIP 49 159 PM 4/13 CWOP EASTPORT 48 228 PM 4/13 CWOP WEST ISLIP 47 138 PM 4/13 TRAINED SPOTTER SOUTHOLD 47 305 PM 4/13 CWOP

So far the main impact on temperatures have been muted highs. This is the first April 1-13 at Newark not to reach 70 since 2009. Time Series Summary for Newark Area, NJ (ThreadEx) Click column heading to sort ascending, click again to sort descending. Ending Date Highest Max Temperature Apr 1 to Apr 13 Missing Count 2020-04-13 69 1 2019-04-13 80 0 2018-04-13 84 0 2017-04-13 84 0 2016-04-13 80 0 2015-04-13 71 0 2014-04-13 83 0 2013-04-13 85 0 2012-04-13 71 0 2011-04-13 87 0 2010-04-13 92 0 2009-04-13 68 0

These big spring -NAO drops have become common since 2012. +NAO winter followed by strong spring blocking when the sun returns to the Arctic.