GOES-13 6.5 µm water vapor images + surface frontal and pressure analyses

A strong Northeast US coastal storm developed on 08 November 2010, which produced as much as 3.56 inches of rainfall in Maine, 2.5 inches of snow in Massachusetts and New York, and wind gusts to 63 mph in Maine (and 75 mph on top of Mt. Washington, New Hampshire). AWIPS images of 4-km resolution GOES-13 6.5 µm “water vapor channel” data (above) showed a classic example of a signature of an occluding cyclone, with a spiral of dry air (yellow to orange color enhancement) wrapping inward around the storm center.

A sequence of 1-km resolution MODIS 6.7 µm water vapor images (below) shows a bit more detail at various stages of the storm’s life cycle.

MODIS 6.7 µm water vapor images + surface frontal and pressure analyses

A sequence of 1-km resolution POES AVHRR 10.8 µm “IR window” images (below) showed an arc of cold clouds that wrapped inland ahead of the occluded frontal boundary.

POES AVHRR 10.8 µm IR images + surface frontal and pressure analyses

Additional 1-km resolution POES AVHRR derived products can be used to further characterize the clouds over a particular region. For example, the 22:32 UTC Cloud Top Temperature (CTT), Cloud Height, and Cloud Type products are shown below. The coldest CTT values associated with the well-defined inland cloud arc were -55º C, with a maximum cloud height value of 11 km. The Cloud Type product can be used to discriminate between water droplet clouds, supercooled water droplet clouds, opaque ice crystal clouds, cirrus clouds, or clouds that are likely overshooting the tropopause.

POES AVHRR Cloud Top Temperature product

POES AVHRR Cloud Top Height product

POES AVHRR Cloud Type product

Note to NWS forecast offices: MODIS and POES AVHRR satellite images and products such as those seen above can be added to your local AWIPS workstations via Unidata LDM subscription.

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Storm track of Tomas (during the period 29 September - 05 November 2010)

Tropical Storm Tomas became the 19th named storm of the 2010 Atlantic tropical cyclone season on 29 September 2010 (NHC advisory archive). The path of Tomas from the CIMSS Tropical Cyclones site can be seen above, along with a plot of the Advanced Dvorak Technique (ADT) intensity estimate (below) which showed that there were a number of fluctuations in the intensity of Tomas: it initially intensified into a Category 1 and then a Category 2 hurricane as it crossed the Windward Islands of the Lesser Antilles on 30-31 August, but then was degraded to a Tropical Storm due to unfavorable deep layer wind shear on 01 November. Atmospheric steering currents then helped Tomas turn to the north, and the storm re-intensified into a Category 1 hurricane as it passed between Cuba and Hispaniola on 05 November.

Automated Dvorak Technique (ADT) plot for Tomas

Animations of GOES-13 0.63 µm visible channel imagery and GOES-13 10.7 µm IR channel imagery (below) revealed a number of convective bursts as Tomas intensified into a Category 1 hurricane on 30 August.

GOES-13 0.63 µm visible channel images

GOES-13 10.7 µm IR images

A comparison of a GOES-13 10.7 µm IR image with the corresponding SSMI/S 85 GHz microwave image around 22:45 UTC on 30 August (below) showed that Hurricane Tomas had a large closed eye and a well-defined spiral band extending northward as the storm passed to the west of the Windward Islands of St. Lucia and St. Vincent.

Hurricane Tomas GOES-13 10.7 µm IR + SSMI/S 85 GHz microwave images

On 05 November, AWIPS images of POES AVHRR 10.8 µm IR data (below) showed that Hurricane Tomas was exhibiting IR brightness temperatures as cold as -93º C (darker purple color enhancement) as the storm passed between Jamaica and Hispaniola.

POES AVHRR 10.8 µm IR images

Note the improvement in cloud top temperature structure that can be seen on the 1-km resolution POES AVHRR IR image, compared to the corresponding 4-km resolution GOES-13 IR image (below). On the POES AVHRR image, subtle storm top gravity waves can be seen emanating southward away from the region of coldest cloud tops, and the transverse banding structure along the western and southwestern edge of the storm are better resolved.

POES AVHRR 10.8 µm IR image + GOES-13 10.7 µm IR image

Note to NWS users: POES AVHRR images and products can be added to your local AWIPS workstations (via Unidata LDM subscription): for more details, see the AVHRR Imagery and Products in D-2D site.

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250-meter resolution MODIS true color and false color RGB images

A comparison of a 250-meter resolution MODIS true color Red/Green/Blue (RGB) image (created using Bands 1/4/3) with the corresponding MODIS false color image (created using Bands 7/2/1) obtained from the SSEC MODIS Today site confirmed that the brighter white area seen in far north-central Wisconsin on 05 November 2010 was a patch of snow that remained on the ground following a period of lake-effect snow 1-2 days earlier. Snow cover and/or ice appears as cyan-colored features in the MODIS 7/2/1 RGB false color image.

AWIPS images showing another set of MODIS false color RGB images (below, created using Bands 1/7/7) showed that the patch of snow cover — which appeared as a red-colored feature in these particular RGB images — remained stationary between the times of the Terra satellite overpass (around 16:58 UTC, or 11:58 am local time) and the Aqua satellite overpass (around 18:40 UTC, or 1:40 pm local time), which again confirmed that this was snow cover rather than a cloud feature. Upson in Iron county had received 3 inches of snow during the preceding 48 hours, with Butternut in Ashland county receiving 1.0 inch of snowfall.

MODIS false color RGB images

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AO&SS building rooftop camera (facing northwest)

Nocturnal radiation fog formed over Lake Mendota (the largest of the 4 lakes in the immediate vicinity of Madison, Wisconsin) on 02 November 2010 — the evolution and motion of this fog was captured by a northwest-facing camera (above; smaller 640×480 version) mounted on the top of the Atmospheric, Oceanic, and Space Sciences building on the University of Wisconsin – Madison campus (Google map). The camera video begins at 09:54 UTC (4:54 am local time) and ends at 15:39 UTC (10:39 am local time). During the daylight hours, there even appeared to be evidence of a local-scale cyclonic circulation within the fog feature along the southern shore of Lake Mendota. Thanks to Pete Pokrandt, AOS, for supplying the QuickTime animation.

AWIPS images of the 4-km resolution GOES-13 fog/stratus product at night (followed by 1-km resolution GOES-13 0.63 µm visible channel images after sunrise) are shown below. In spite of the high amount of noise and “false fog/stratus pixels” (yellow enhancement), the GOES-13 fog/stratus product did show a relatively persistent fog signal over Lake Mendota through much of the night-time hours — and then the fog features could then be seen dissipating on the GOES-13 visible images after sunrise. On both the rooftop camera video and the GOES-13 visible images, the fog features appeared to be drifting to the southwest — in fact, the surface visibility at the Middleton Municipal Airport (KC29, located just to the west of Lake Mendota) dropped to 0.15 mile, while the surface visibility at Madison’s Dane County Regional Airport airport (KMSN, located just to the east of Lake Mendota) only fell to 3.0 miles.

GOES-13 fog/stratus product + GOES-13 0.63 µm visible channel images

An AWIPS image of the POES AVHRR 1-km resolution Sea Surface Temperature product (below) indicated that SST values over the central portion of Lake Mendota were as warm as 54.5º F at 23:55 UTC (6:55 PM local time) before sunset. With light winds and strong radiational cooling during the night, the surface air temperate at nearby Madison Dane County Regional Airport (KMSN) cooled to 27º F — and with such a large difference in water vs air temperature, thick fog eventually began to form over Lake Mendota.

POES AVHRR Sea Surface Temperature product

Looking ahead to the future GOES-R era, Geostationary Cloud Algorithm Test-bed (GEOCAT) images of a GOES-R Fog Probability product (below) did indeed suggest that fog probabilities were increasing across south-central Wisconsin during the night-time hours as radiational cooling continued.

GEOCAT experimental GOES-R Fog Probability product

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