The Historic Nor'easter of 13-14 March 2010
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The historic nor’easter of 13-14 March 2010 By Richard H. Grumm National Weather Service 1. INTRODUCTION Gloria September 1985 (2.0m), Hurricane Donna September 1960 (1.73m), and the An historic nor’easter affected the East Coast of nor’easter of 12-13 December 1992 (1.75m). A the United States on 13-14 March 2010. The total of 17 tropical storms produced strong storm storm will be remembered for heavy rainfall surges. The list of extratropical cyclones (Fig. 1), flooding, strong winds, and the coastal includes many memorable East Coast Winter 1 surge . Hurricane force wind gusts were Storms (ECWS) and famous nor’easters reported at Kennedy International Airport including the 31 October 1991 (1.40m), 13 (KJFK) around 0000 UTC 14 March 2010 when March 1993 “Superstorm” (1.46m), and the 7-8 wind gusts reach 64KTS (74 mph). Islip had 54 January 1996 “Blizzard of 1996” (1.35m) and 2 KTS winds . The strong winds produced the 14-15 November 1995 nor’easter (1.24). widespread power outages, downed trees, and Storm surges and coastal flooding are often produced coastal flooding due to a strong storm overlooked but important aspect nor’easters. The surge. storm of 13-14 March produced a surge of 1.28 m. This storm has been compared to several past storms. The nor’easters of 12-13 December 1992 As with many nor’easters, this storm produced and 07-08 January 1996 storms both produced high winds. The highest gusts were on Long strong storm surges along the East Coast. Unlike Island including KJFK (75 mph) and Breezy this storm, these storms produced areas of heavy Points (66 mph). Table 1 lists some of the higher snowfall. Another similar storm, which winds reports for the event for gusts over 50 produced heavy rainfall, was the 3-4 March MPH. The strongest winds were primarily along 1993 event. All of these storms had strong the coast. However, strong winds and wind easterly winds with significant u-wind anomalies damage were reported well into central north of the cyclone. It was in this general area Pennsylvania. where these storms produced the most significant impact. The 850 hPa winds and u- This event also produced locally heavy rainfall. wind anomalies during the peak of the 13-14 Coastal areas received 2 to 3 inches with locally March 2010 nor’easter are shown in Figure 2. higher amounts exceeding 5 inches. A higher elevation report in southern Pennsylvania Colle et al (2010) examined storms which received 6.25 inches of rainfall. Table 2 lists produced storm surges in New York City. They rainfall amounts in excess of 5 inches. There listed all storms which produced storms which were over 165 reports of 3 inches or more produced significant surges above the mean-high observed liquid equivalent precipitation. water mark (Colle et al. 2010: Table 1) separating out tropical cyclones (Tab le2: Colle This paper will provide an overview of the et al. 2010). The top 3 storms were Hurricane historic nor’easter of 13-14 March 2010. The focus is on the pattern and the significant 1 Information provided by Brian Colle SUNY-Stony weather impacts. A comparison of this storm to Brook. several notable nor’easters from the published literature is presented too. 2 KISP 132356Z 08027G42KT 4SM RA BKN010 2. METHODS AND DATA OVC016 09/07 A2958 RMK AO2 PK WND 10054/2312 SLP017 P0008 60042 T00940067 10094 The 500 hPa heights, 850 hPa temperatures and 20089 58017 $= winds, other standard level fields were derived from the NCEP GFS, GEFS, and the Where F is the value from the reanalysis data at NCEP/NCAR (Kalnay et al. 1996) reanalysis each grid point, M is the mean for the specified data. The means and standard deviations used to date and time at each grid point and σ is the compute the standardized anomalies were from value of 1 standard deviation at each grid point. the NCEP/NCAR data as described by Hart and Grumm (2001). Anomalies were displayed in Model and ensemble data shown here were standard deviations from normal, as primarily limited to the GFS and GEFS. The standardized anomalies. All data were displayed 1.25x1.25 degree JMA data may be used when it using GrADS (Doty and Kinter 1995). becomes available. The NAM and SREF data were also available for use in this study. The standardized anomalies computed as: Displays will focus on the observed pattern and some forecast issues associated with the pattern. SD = (F – M)/σ () For brevity, times will be displayed in day and Figure 1 Total observed liquid precipitation (mm) from 1200 UTC 12 March through 1200 UTC 15 March 2010. From the unified precipitation data set. Return to analysis section. hour format such at 14/0000 UTC signifies 14 Jersey, New York and then southern New March 2010 at 0000 UTC. England. The heavy rain axis in Figure 1 appears to align well with this feature to include 3. RESULTS the rainfall maximum over the Appalachians of Maryland and central Pennsylvania. Wind i. Synoptic scale pattern reports and damage appear to be well aligned with this feature too. The strong easterly jet was The large scale pattern over North America is a critical player in this event. shown in Figure 3. The key features associated with this event include the ridge with positive A regionalized view of the PW and PW anomalies height anomalies over eastern Canada and the is shown in Figure 8. These data show that the deep trough with negative height anomalies strong southerly winds (not shown) in the warm moving from the central United States (Fig. 3a) sector taped some deep tropical moisture with 24 which moves over the Eastern United States to 32 mm PW values wrapping about the series of (Fig. 3d-f). A strong subtropical jet (Fig. 4) was cyclones into the Mid-Atlantic region. PW present at 3250 hPa with 2 to 3SD anomalies in anomalies of +1 to +3 SDs were present in and the core of the jet as it moved across the Gulf of near the region of heavy rainfall. This is best seen Mexico and up the East Coast. between 13/0600 and 14/0000 UTC. The really deep moist air with +5SD anomalies and PW values over 50 mm never surge into the cyclone. The precipitable water (PW) and PW anomalies Nor were they forecast to do so. showed a surge of PW along the coast and over the eastern Atlantic (Fig. 5). The storm was able to ingest some of this high PW air. iii. Comparison to historic cases ii. Regional pattern and anomalies Colle et al (2010) listed nor’easters and tropical storms which produced surges over the mean Figure 6 shows the NAM 00-hour forecasts of high water level in New York City. All of the the surface features from 12/18000 through events to which this event was being compared 14/1800 UTC. A strong anticyclone was present to during its evolution are in that Table 1 of their over New England and to the northeast with paper. Storms with similar characteristics can 1SD above normal surface pressure anomalies. and do produce similar weather and weather Beneath the 500 hPa low (Fig. 3) there was low impacts. They details will vary as no two storms pressure over most of the eastern United States are true analogs of each other. with -1 to -3 SD surface pressure anomalies. An initial cyclone moved up the Ohio Valley and Some key features of the 3-4 March 1993 storm there were hints of surges of low pressure along are shown in Figure 9. The 500 hPa heights (not the coastal zone. shown) had a cut-off low. This event lacked cold air and produced heavy rainfall with a maximum The key to this event and its complex cyclone in western Maryland at 8.9 inches. The surface evolutions, not examined here in detail, was the pattern was remarkably similar to that shown in strong pressure gradient over the Mid-Atlantic Figure 6. The 850 hPa jet was equally as region and southern New England. This was the impressive though it maximized farther west area of concern and the area were the strong then the 13-14 March 2010 event. The storm easterly flow (Fig. 7) developed. produced a 1.03 meter surge in NYC (Colle et al. Table 1) on 5 March 1993. The observed The wind anomalies show the increase in the precipitation for this event is shown in Figure winds over time with -5SD u-winds developing 10. The easterly winds produced locally heavy around 13/0600 UTC and increasing to -6SD rainfall as the event moved up the Appalachian over Pennsylvania by 13/1200 UTC. This strong Mountains. The pattern of heavy rainfall was u-wind anomaly then lifted slow to the east- similar and there were local maximums in the northeast over the next 6-24 hours into New mountains of 96-100 mm of precipitation. concept. It should clear to the reader that the Another similar event, which caused massive 75km GEFS will not pick up the maximum and coastal storm surge and flooding issues (Colle et terrain enhanced values that higher resolution al 2010), was the storm of 11-13 December 1992 models would detect. (Fig. 11). This storm was associated with cold air and there was some extremely heavy The SREF QPF for the 36 hour period ending at snowfall (2 to 3 feet) in the mountains of 1800 UTC 14 March 2010 is shown in Figure Maryland and Pennsylvania.