Severe weather in New England

June 1st, 2011 |
GOES-13 10.7 µm IR images + SPC severe weather reports

GOES-13 10.7 µm IR images + SPC severe weather reports

AWIPS images of 4-km resolution GOES-13 10.7 µm IR images with overlays of SPC storm reports (above) showed the large Mesoscale Convective System that moved across the New England region of the US on 01 June 2011. This was part of a long line of thunderstorms that stretched from Maine to West Virginia, as seen on POES AVHRR 0.63 µm visible images (below).

POES AVHRR 0.63 µm visible channel images

POES AVHRR 0.63 µm visible channel images

One of the more notable events was a tornado that produced EF-3 damage in the Westfield and Springfield areas in southwestern Massachusetts. Images of GOES-13 10.7 µm IR images with an overlay of the Automated Overshooting Top Detection product (below) revealed a overshooting top (OT) just to the northwest of Westfield (station identifier KBAF) at 20:02 UTC — about 28 minutes later the tornado was reported in Westfield at 20:30 UTC (also see the NOAA Hazardous Weather Testbed blog). It is important to mention that the OT markers as plotted in AWIPS are parallax-corrected, which moves them slightly to the southeast of the coldest cloud tops on the non-parallax-corrected GOES IR imagery in AWIPS.

Note that another OT was detected farther to the north at 19:45 UTC, with the cell that later produced damaging winds at Northampton at 19:58 UTC. and Hadley at 20:15 UTC.

GOES-13 10.7 µm IR images + Automated Overshooting Top Detection

GOES-13 10.7 µm IR images + Automated Overshooting Top Detection

A 1-km resolution POES AVHRR 10.8 µm IR image at 20:39 UTC with an overlay of the cumulative SPC storm reports up to that time (below) offered a more detailed view of the cold storm top IR brightness temperatures (which were as cold as -79º C).

POES AVHRR 10.8 µm IR image + cumulative SPC storm reports

POES AVHRR 10.8 µm IR image + cumulative SPC storm reports

CIMSS participation in GOES-R Proving Ground activities includes making POES AVHRR images and products available for National Weather Service offices to add to their local AWIPS workstations, as well as the testing and evaluation of products such as Automated Overshooting Tops Detection during the NOAA Hazardous Weather Testbed. The VISIT training lessons “POES and AVHRR Satellite Products in AWIPS” and “Objective Satellite-Based Overshooting Top and Enhanced-V Anvil Thermal Couplet Signature Detection” are available to help users understand these products and their applications to weather analysis and forecasting.

Atlantic Tropical Invest 93L: a residual MCV from a Midwest MCS?

June 1st, 2011 |
GOES-13 6.5 µm water vapor images (click to play animation)

GOES-13 6.5 µm water vapor images (click to play animation)

An area of organized convection was seen moving rapidly southwestward across the western Atlantic Ocean on 31 May 2011, not far off the East Coast of the US. AWIPS images of GOES-13 6.5 µm “water vapor channel” data (above; click image to play animation) suggested that this area of convection over the Atlantic (which was designated Atlantic Tropical Invest 93L on the morning of 01 June) may have been due to a residual Mesoscale Convective Vortex (MCV) that was created by a large Mesoscale Convective System (MCS) over the Upper Midwest region of the US 2 days earlier (for additional information, see the WeatherMatrix Blog and the Weather Underground WunderBlog). A comparison of a POES AVHRR 0.63 µm visible image at 12:37 UTC with ASCAT scatterometer surface winds about 2 hours later at 14:40 UTC (below) revealed a well-defined cyclonic circulation within the convective cluster on 31 May.

POES AVHRR 0.63 µm visible channel image + ASCAT scatterometer surface winds

POES AVHRR 0.63 µm visible channel image + ASCAT scatterometer surface winds

MODIS Sea Surface Temperature (SST) product images (below) indicated that the SST values within the Gulf Stream were in the upper 70s to low 80s F (darker red color enhancement) — and these warm waters may have helped the MCV convection to organize and intensify as it eventually moved southwestward over the Gulf Stream.

MODIS Sea Surface Temperature product images

MODIS Sea Surface Temperature product images

The feature could also be followed on the MIMIC Total Precipitable Water (TPW) product (below; click image to play animation) — TPW values remained above 40-45 mm during the entire journey across the western Atlantic Ocean, and peaked at 58 mm at 18:00 UTC on 31 May as the disturbance began to move over the warmer waters of the Gulf Stream.

MIMIC Total Precipitable Water (TPW) product (click to play animation)

MIMIC Total Precipitable Water (TPW) product (click to play animation)

A sequence of MODIS 11.0 µm IR and POES AVHRR 10.8 µm IR images (below) showed minimum cloud top IR brightness temperature values in the -71º C to -83º C range during the 31 May to 01 June period.

MODIS 11.0 µm IR + POES AVHRR 10.8 µm IR images

MODIS 11.0 µm IR + POES AVHRR 10.8 µm IR images

A somewhat similar case was noted back in July 1999, when MCV-related convection moved inland produving large hail, damaging winds, and heavy rain in parts of North Carolina and South Carolina.

CIMSS participation in GOES-R Proving Ground activities includes making a variety of POES AVHRR, MODIS, and MIMIC TPW images and products available for National Weather Service offices to add to their local AWIPS workstations. The VISIT training lessons “POES and AVHRR Satellite Products in AWIPS”, “MODIS Products in AWIPS“, and “Morphed TPW Detection (MIMIC)” are available to help users understand these products and their applications to weather analysis and forecasting.

[Added, 7 June 2011: An enhanced infrared loop using data from GOES-13 that shows the entire life of the MCV is available here. Note: 34 megabyte file size]