Persistent rains over the New York City metropolitan area have caused urban flooding on 29 September (29 September is the wettest day since 1948 in NYC well!). MIMIC TPW, above (source), shows moisture moving inland from the Atlantic Ocean. It’s often the case that heavy rain is accompanied by advection of moisture at multiple layers in the atmosphere; the Advected Layer Precipitable Water product, below (source), identifies two sources of moisture moving over metropolitan New York: moisture from the Atlantic is moving towards New York in the layer from the Surface to 850 mb; moisture from the Great Lakes is moving towards New York in the 700-500 mb layer, accompanying what appears to be a mid-level impulse. The edge of that feature from 700-500 mb is close to New York at 1800 UTC, the end of the animation, as shown in this annotated image (see the dotted orange line in the lower left image).

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GOES-16 imagery, below, shows persistent redevelopment of convection over western Long Island/metropolitan New York City. As in the ALPW fields, a boundary is approaching metropolitan New York City by the end of the animation (1851 UTC). Perhaps the passage of that boundary will lessen the likelihood of convective redevelopment (caveat: your blogger is not a paid forecaster!) Abundant moisture (values exceeding 1.6″) is to the southeast of New Jersey (reddish orange in the enhancement), with more modest values (1.3-1.4 inches, yellow in the enhancement used) over New Jersey/eastern Pennsylvania.

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GOES-16 Visible/Infrared Sandwich RGB images (above) provided a closer look at the NYC area — METAR 1-hour Precipitation Accumulations were as high as 1.96 inches at Central Park (surface observations), 1.42 inches at Farmingdale (KFRG, surface observations), 1.40 inches at La Guardia Airport (KLGA, surface observations) and 1.24 inches at Kennedy International Airport (KJFK, surface observations). Such rainfall rates contributed to the high precipitation totals across the region, with amounts exceeding 9 inches in the NYC area.

GOES-16 Visible/Infrared Sandwich RGBs with cursor sampling of the associated Rainfall Rate and Cloud Top Height derived products (below) displayed Rainfall Rates of 0.56 to 0.67 inch per hour for 3 consecutive 5-minute images — associated with the thunderstorm that was passing over/near La Guardia Airport KLGA (where the 1-hour METAR Precipitation Accumulation at 1300 UTC was 1.40 inches). Taking parallax into account, the ~40 kft cloud tops were actually located about 16 km (10 miles) to the south (closer to KLGA).

AWIPS cursor sampling of GOES Level 2 derived products associated with a variety of RGBs is available via “Satellite -> Local Menu Items“. This technique of sampling satellite-derived rainfall rates could prove to be helpful in areas where radar coverage is poor (or unavailable). 

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NOAA-20 overflew New York just before 1800 UTC on 29 September 2023. In the Sounding Availability Plot below, a line of NUCAPS profiles stretching east-northeastward from the central DelMarva peninsula are plotted in green — meaning the infrared retrieval converged to a solution — and boxed in purple. The individual profiles are shown in the animation, with locations indicated. The 3 easternmost soundings show a profile very similar to the 1200 UTC sounding at Upton, NY (also available here); that is, nearly moist adiabatic and close to saturation.

NUCAPS profiles can be horizontally interpolated to a grid. The 850-500 mb lapse rate computed from those fields is shown below. The most unstable air stretches back into northern Virginia.

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Two Mesoscale Prediction discussions from NOAA’s Weather Prediction Center (WPC) (11:35 PM on the night before the event; 5:05 AM on the morning before the event) show how well this event was anticipated. New York City’s Emergency Management issued this Press Release long before the flooding occurred.

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Scientists at CIMSS are putting a test version of the CSPP Geosphere site through its paces. The new version includes Level 2 products (Cloud Top Height, Cloud Top Pressure; both can be displayed using geo2grid software) — at full ABI resolution. The True-Color animation above shows Tropical Storms Phillipe and Rina in close proximity over the tropical Atlantic Ocean. (Rina’s exposed low-level circulation is very apparent!) The animation below include a Cloud Top Height overlay, with a scale shown. Cloud Top Heights over Rina peak at around 16000 m; those over Phillipe include values exceeding 17000 m

A toggle between the two images at 1650 UTC is shown below. Screen controls are not saved when imagery are exported, but those controls can be seen in this screenshot.

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Stay tuned for an announcement for the update to CSPP Geosphere!

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1-minute Mesoscale Domain Sector GOES-18 (GOES-West) Dust RGB images (above) showed a plume of resuspended ash (brighter shades of pink) from the 1912 Novarupta-Katmai eruption in Alaska, which was being transported offshore across the Shelikof Strait toward Kodiak Island on 27 September 2023. Surface volcanic ash within the Valley Of Ten Thousand Smokes.was being lofted by strong northwesterly winds.

Volcanic ash (VA) was reported at Kodiak Airport (PADQ) for 7.5 hours, from 2123 UTC on 27 September to 0453 UTC 28 September (below) — for example, see METAR cursor sampling at 2200 UTC, 2300 UTC and 0000 UTC — but the ash was not restricting surface visibility below 10 miles.

1-minute GOES-18 Nighttime Microphysics RGB + daytime True Color RGB images from the CSPP GeoSphere site (below) provided a more detailed view of the ash plume.

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New routine schedule

EWS-G1 (Electro-optical Infrared Weather System Geostationary) is a U.S. Space Force mission. The imager is now running a different routine scan schedule, as can be seen on the UW/SSEC geo-browser. This schedule includes scans of the Indian Ocean, the extended Indian Ocean and Full Disks. Previously only Full Disk images had been obtained every 30 minutes. An EWS-G1 “quick-guide (pdf).” EWS-G1 imagery has been available via the UW/SSEC since late 2020. The EWS-G1 was formerly NOAA’s GOES-13. EWS-G1 has employed the “XGOHI” remapping of data before GVAR generation, to handle larger inclination angles. This capability was first employed on GOES-10 (and then GOES-12) when their images provided special coverage of the Southern Hemisphere for a combined almost 7 years.

A loop of the coverage of three scans (mp4 and animated gif).

GOES-15 has become EWS-G2

It was recently announced by the Secretary of the Air Force that GOES-15 has become EWS-G2: “The U.S. Space Force accepted the transfer of a second geostationary weather satellite from the National Oceanic and Atmospheric Administration to extend persistent weather coverage of the Indian Ocean region until the 2030 timeframe. … As it currently does with EWS-G1, NOAA will operate EWS-G2 on behalf of the Space Force from the NOAA Satellite Operations Facility in Suitland, Maryland, and Wallops Command and Data Acquisition Station in Wallops Island, Virginia.”

EWS-G2 has the same spectral coverage as the EWS-G1. The EWS-G2 was formerly NOAA’s GOES-15. GOES-15 was launched in March 2010 and the first GOES-15 images were sent on April 6, 2010. A GOES-15 technical report which was written soon after launch.

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The posted near realtime imagery are free for public use (please credit UW-Madison/SSEC) and users can contact UW/SSEC Satellite Data Services for information on data access / subscription. Most of the above images were made using the McIDAS-X software. NOAA/NESDIS/STAR supplies some calibration support of this imager.

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