donsutherland1

With the rain that deluged Wilmington, NC from Hurricane Florence, 2018 is now the wettest year on record in Wilmington. Through 1 pm EDT today, Wilmington has received 86.25" rain. The five wettest years on record are: 1. 86.25", 2018 2. 83.65", 1877 3. 73.49", 2015 4. 72.06", 1999 5. 72.05", 1946 Four of the ten wettest years on record have occurred 2000 or later and one of ten driest years on record occurred 2000 or later. The driest year on record was 1909 when annual precipitation came to 27.68". Records for Wilmington go back to 1871.

While we wait for the potential tropical downpours from what's left of Florence, it should be noted that Baltimore has received 0.09" rain today bringing its year-to-date precipitation to 49.05". That ranks 2018 as that city's 29th wettest year on record, just ahead of 1924 when annual precipitation was 49.04". There remains a chance that 2018 could become Baltimore's wettest year on record.

The NHC seems to have settled on the ECMWF’s track.

Keep us posted and stay safe.

That highlights the importance of the NHC's warning about flash flooding: Life-threatening, catastrophic flash flooding and prolonged significant river flooding are likely over portions of the Carolinas and the southern and central Appalachians through early next week, as Florence is expected to slow down as it approaches the coast and moves inland.

Since 11:20, New Bern, NC has picked up 0.66" rain during a 21-minute span. The wind has also gusted as high as 51 mph there.

The first 6 days of September saw the temperature average 80.2° in Central Park, the 8th warmest start on record. Back then, it was noted that 57% of the prior cases saw September finish with a monthly average temperature of 70.0° or above. The statistical probability of such an outcome based on a sensitivity analysis for 6 days of data, MEX MOS for the following 10 days, and EPS for the subsequent five days was also 57%. Since then, the monthly average has declined on account of cooler readings. Through September 12, the monthly average had decreased to 73.2°. That ranks 36th warmest for the 1869-present period. During the 1869-2017 period, there were 42 cases in which the first 12 days of September had a mean temperature of 73.0° or above. 60% of those cases wound up having a monthly mean temperature of 70.0° or above. The statistical probability was 56% for those cases. The lowest monthly mean temperature among those cases was 66.5° in 1966. The highest was 74.5° in 2015. Both the mean and median figures for those 42 cases were 70.3°. Re-running the sensitivity analysis for the 12 days of data and same approach to the guidance (MEX MOS and EPS), the implied statistical probability of September’s finishing with a mean temperature of 70.0° or above has increased to 59%. The likely range for the monthly mean temperature was 69.2° - 72.6°. So, at least at this point in time, September 2018 appears to have remained on course for yet another exceptionally warm monthly average temperature. Finally, with this morning’s 0.13” rain, New York City’s annual precipitation has risen to 43.70”, which ranks 81st. It is very likely that New York City will receive 50” or more precipitation in 2018 and somewhat likely that it could approach or reach 60”. Using the historical 1869-2017 period, the associated probabilities are: 50” or more: 94% 60” or more: 22% Using the 1971-2017 period, which is a wetter regime, the associated probabilities are: 50” or more: 96% 60” or more: 39% In terms of significant rainfall in the medium-term, the 9/13/2018 0z ECMWF took the remnants of Florence on a course that would bring New York City more than an inch of rain (the ECMWF forecasts >2” for a large part of the area). But that’s still 4-6 days away, so such an outcome remains subject to considerable uncertainty.

With 0.49" rain in the last hour, Baltimore's annual precipitation has reached 48.87”. 2018 now ranks as the 30th wettest year on record in Baltimore. Some statistical probabilities based on the 9/15-12/31 1871-2017 precipitation amounts: Probability of 50" or more annual precipitation: >99% Probability of 60" or more annual precipitation: 53% Probability of record annual precipitation: Nearly 25%

Select Record Low Maximum Temperatures for 9/10: Bridgeport: 64° (old record: 67°, 1954) Danbury: 59° (old record: 66°, 1975) Islip: 66° (tied record set in 1978) New Haven: 64° (old record: 67°, 1956) New York City-JFK: 65° (old record: 68°, 1967 and 1975) New York City-LGA: 67° (old record: 68°, 1969) Newark: 63° (old record: 68°, 1978) Poughkeepsie: 59° (old record: 65°, 1998) White Plains: 61° (old record: 64°, 1978)

Numerous locations around the area could set or tie record low maximum temperatures. However, the guidance suggests that readings could begin rising toward midnight, so it could be a close call.

Through 8 am this morning, New York City has received 42.90" precipitation. That ranks 84th highest in terms of annual precipitation. Farther south, Baltimore's precipitation to date ranks 32nd and Washington, DC's ranks 35th. Both Baltimore and Washington, DC could be in a position to challenge their annual record should they receive significant rainfall from Florence. As for New York City, it appears very likely that the City will record its 33rd year on record with 50" or more precipitation in 2018. That would extend what has been a historically wet period that began in 1971. Number of Years with 50” or more Precipitation: 1869-1970: 12; Return Time: 8.5 years 1971-2017: 20; Return Time: 2.4 years Historic (1869-2017): 32; Return Time: 4.7 Years Were September to see no additional precipitation, which is extremely unlikely, just 7.10" precipitation would be needed to reach 50.00" for the year. During the 1869-2017 period, just 19 (13%) years saw < 7.10" precipitation in the October-December period. During the 1971-2017 period, only 2 (5%) years saw < 7.10" precipitation in the October-December period. In terms of statistical probabilities based on a normal distribution, the historic probability of < 7.10" October-December precipitation is approximately 16% and the 1971-2017 probability is just under 14%. The last year with 50" or more precipitation was 2014 when yearly precipitation came to 53.79". Prior to that, 2011 saw 72.81" precipitation. New York City's record is 80.56", which was established in 1983.

It's unfortunate. Nevertheless, it was exceptionally cool and quite a break from what we had been experiencing earlier in the month.

The NWS daily climate report shows 62 as the high temperature at 2:24 am.

Yes. That’s the one that made landfall Near Atlantic City.

Florence has regained hurricane status.

With today’s rainfall through 9 am, 2018 now ranks among the 40 wettest years in both Baltimore and Washington, DC. Totals through 9 am: Baltimore: 47.13” 35th highest amount Washington, DC: 45.20” 39th highest amount

It is currently raining lightly in White Plains.

When one uses historical data, one can't assume that a single look at the data for a storm provides a complete picture. First, the guidance suggested that Florence would track westward and perhaps even a little south of west. One could examine the historical data at its expected position e.g., 24 hours in advance, for additional context (which would have implied a possible threat). None of those tweeting about the historical tracks mentioned this. Why? One can't look only superficially. Second, one also has to regularly examine the data, as the storm progresses, because the synoptic pattern is not static or constrained by what happened in the past. It is dynamic. Historical data should not be used as a substitute for the synoptic pattern or guidance. It can complement such information. Based on Florence's 11 am AST position, (24.5N 54.3W) and an examination of all tropical storms or hurricanes that passed within 200 nautical miles of that position, one finds 95 tropical cyclones. Six of those tropical cyclones went on to make U.S. landfall. 1880 Hurricane #4: SE Florida, Category 2 1893 Hurricane #6, Georgia, Category 3 1903 Hurricane #4, New Jersey, Category 1 1933 Hurricane #6, North Carolina, Category 1 1961 Esther, Massachusetts, Tropical Storm 2003 Isabel, North Carolina, Category 2 So, this data essentially confirms what the guidance has been implying: the threat of a possible U.S. landfall is increasing. If one examines the synoptic pattern using the EPS, most ensemble members have suggested possible landfall from Florida to North Carolina. The operational ECMWF falls within that large cluster. The historical data had 4/6 (67%) of the landfalling storms make landfall in that area. Given the synoptic pattern, the probability of landfall is far higher than the 6% figure implied by the historic tracks. That probability also increases based on the NHC's forecast position 24 hours from now. Such landfall is still not assured, as shown on the 12z GFS, but it is probably at least somewhat more likely than no landfall at this point in time. The Southeast appears to have the highest risk of seeing such landfall based on all of the above information. Finally, in this thread a reference to Sandy was made. Although Sandy's track was essentially unprecedented for a tropical cyclone, winter storms have made such a turn under the influence of powerful blocking (as had been present in late October 2012).

Much of New England also saw among its warmest weeks. Boston: 77.8° (3rd warmest) Burlington: 74.1° (tied 3rd warmest) Concord: 73.0° (6th warmest) Manchester: 75.9° (2nd warmest) Portland: 71.4° (3rd warmest) Providence: 76.1° (4th warmest)

I'm glad that's all it was. It could have been much worse.

Parts of New England had among their warmest first weeks in September. Some highlights: 9/1-7/2018 Mean Temperature and Rank: Boston: 77.8° (3rd) Bridgeport: 77.1° (4th) Burlington: 74.1° (tied 3rd) Concord: 73.0° (6th) Manchester: 75.9° (2nd) Milton: 74.7° (3rd) Nantucket: 70.4° (6th) New Haven: 76.9° (2nd) Portland: 71.4° (3rd) Providence: 76.1° (4th) Worcester: 72.5° (9th)

From the NHC's 11:00 AST discussion: The risk of other direct impacts associated with Florence along the U.S. East Coast next week has increased. However, there is still very large uncertainty in model forecasts of Florence's track beyond day 5, making it too soon to determine the exact location, magnitude, and timing of these impacts. Interests near and along the U.S. East Coast should monitor the progress of Florence through the weekend and ensure they have their hurricane plans in place.

Such a track is well within the realm of possibility. The threat to the East Coast has increased in recent days. By early next week, the details will start to come into focus.

Through September 6, New York City (Central Park) has had a mean monthly temperature of 80.2°. Only 1898 (84.2°), 1953 (83.1°), 1973 (82.6°), and 1961 (82.3°) had a warmer start to the month. Further, since 1869, only 7 prior years saw September 1-6 have a mean temperature of 80.0° or above. In 4/7 (57%) of those prior cases, September wound up having a mean temperature of 70.0° or above. The average figure for those cases was 70.5° and the median figure was 70.3°. If 2018 has a mean September temperature of 70.0° or above, the record streak of consecutive years with such September warmth would be extended to 4. The evolving climate has increased the probability of such warmth in September. Since 1869, there have been 34 cases during which September had a mean temperature of 70.0° or above. 19 (56%) of those cases occurred 1950 and afterward; 12 (35%) of those cases occurred 1980 and afterward. The return time of such September warmth has been decreasing: Historic (1869-2017): 4.4 years Prior to 1950: 5.4 years 1950-2017: 3.6 years 1980-2017: 3.2 years 1990-2017: 3.1 years 2000-2017: 2.3 years 2010-2017: 1.6 years Overall, the September mean temperature has also been increasing: Historic (1869-2017): 67.9° 1961-1990: 68.1° 1971-2000: 68.1° 1981-2010: 68.4° 1988-2017 (latest 30-year period): 68.9° 2000-2017: 69.5° 2010-2017: 70.5° Warmest 30-Year Period on record: 1988-2017: 68.9° Warmest 10-Year Period on record: 2008-2017: 69.9° Based on sensitivity analysis, sing a combination of the actual temperatures through 9/6, the MEX MOS for the next 10 days, and the EPS for the 5 days, and then seasonal readings for the remainder of the month, there is an implied 57% (+/- 5%) probability that September 2018 will have a mean temperature of 70.0° or above. That is almost an identical probability to the historic figure for cases where 9/1-6 had a mean temperature of 80.0° or above. Finally, there is an implied one-in-three chance that September 2018 could go on to have a mean temperature that tops the 74.5° record that was set in 2015.

2015-16 had the strongest El Niño on record. 2016-17 was a la niña winter. Also, on a separate note, the 6z GFS seems to have come more in line with the EPS (northern cluster of solutions) in taking Florence up the Chesapeake Bay. The ECMWF was in the southern cluster.