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  • July « 2008 « CIMSS Satellite Blog
    were even more obvious on an AWIPS image of the 1 km resolution MODIS 11 0 µm IR channel above and also on a comparison of 250 m resolution MODIS true color images from the SSEC MODIS Today site below Since we re on the topic of potential aviation hazards also note the hazy features that were evident on the MODIS true color images just to the east of the transverse banding these hazy features were due to the presence of thick smoke from wildfires that had been burning over parts of northern Saskatchewan Canada for several days see the US Air Quality Smog Blog for details GOES 12 visible imagery indicated that this smoke began moving southeastward across Manitoba and into the north central US on 25 July QuickTime animation The smoke was likely confined to layers aloft but aircraft flying through those smoke layers would encounter significantly reduced visibilities at those altitudes An AWIPS image of the 1 km resolution MODIS 3 7 µm IR channel below showed a large number of fire hot spot signatures across far northern Saskatchewan at 04 05 UTC 10 05 PM the previous evening local time Posted in Air quality Aviation Fire detection GOES 12 MODIS No Comments Hurricane Dolly July 21st 2008 The GOES 12 satellite was placed into Rapid Scan Operations RSO mode to monitor Tropical Storm Dolly on 21 July 2008 the RSO visible images at 5 10 minute intervals above showed that deep convection was increasing around the core of the tropical cyclone Dolly was moving northwestward across the Gulf of Mexico AWIPS images of the MODIS Sea Surface Temperature SST product below showed rather warm SST values mid 80s to near 90 F red colors across much of the western Gulf of Mexico on the previous day which argued in favor of a trend of intensification to hurricane strength For additional satellite imagery and the latest information on Dolly see the CIMSS Tropical Cyclones site 23 July UPDATE Dolly reached hurricane intensity late in the day on 22 July CIMSS Advanced Dvorak Technique intensity plot GOES 12 RSO visible images below show the ragged eye of Hurricane Dolly approaching South Padre Island along the southern coast of Texas A peak wind gust of 76 mph was reported at Port Mansfield and Rincon in Texas with a ship captain off South Padre Island estimating a wind gust of 100 mph wave heights over 24 feet were recorded by an offshore buoy In addition to the strong winds there were also several tornadoes and waterspouts along with rainfall in excess of 12 inches AWIPS images of the 4 km resolution GOES 12 10 7 µm IR channel below revealed that cloud top brightness temperature values around the eye and in the outer band regions were in the 70º to 80º C range black to white colors AWIPS images of the 1 km resolution MODIS 11 0 µm IR channel below indicated that cloud top brightness temperatures were as cold

    Original URL path: http://cimss.ssec.wisc.edu/goes/blog/archives/date/2008/07 (2012-11-14)
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  • June « 2008 « CIMSS Satellite Blog
    as seen in on GOES 11 visible and IR imagery with ASCAT data superimposed below A 30 June 2008 National Hurricane Center discussion for Tropical Storm Cristina also noted TROPICAL STORM CRISTINA DISCUSSION NUMBER 11 NWS TPC NATIONAL HURRICANE CENTER MIAMI FL 200 AM PDT MON JUN 30 2008 THE CLOUD PATTERN ASSOCIATED WITH CRISTINA HAS BECOME LESS ORGANIZED OVER THE PAST SEVERAL HOURS THERE IS A RATHER SHARP EDGE TO THE HIGH CLOUD MASS OVER THE EASTERN SIDE OF THE SYSTEM INDICATIVE OF EASTERLY VERTICAL SHEAR THIS SHEAR IS AT LEAST PARTIALLY DUE TO THE UPPER LEVEL OUTFLOW FROM TROPICAL STORM BORIS LOCATED NOT FAR TO CRISTINA S EAST This sharp eastern cloud edge was quite evident on GOES 11 IR imagery below which also displays the CIMSS wind shear product One factor influencing the lack of organized tropical storm activity in the Atlantic so far this season may have been the persistent Saharan Air Layer and airborne African dust that was frequently observed over the tropical Atlantic basin during the month of June 2008 note the presence of significantly lower MIMIC Total Precipitable Water TPW values during the 27 30 June 2008 period below within the 10 20º N latitude band over the Atlantic Ocean compared to the much higher TPW values over tropical East Pacific where Tropical Storms Boris and Cristina were seen One impact of such a high amount of African dust may be the cooler than normal Sea Surface Temperatures across the tropical Atlantic which would be a negative factor for tropical cyclone formation Posted in GOES 11 POES Satellite winds Tropical cyclones No Comments Clockwise rotating vortex over the tropical Atlantic June 27th 2008 Tony Cristaldi at the National Weather Service forecast office at Melbourne Florida pointed out an interesting feature to us a clockwise rotating vortex over the Atlantic Ocean located just north of the Equator off the northeast coast of Brazil An animation of GOES 12 visible and 3 9 µm shortwave IR images above QuickTime animation shows the feature as it moved westward on 26 June and 27 June 2008 producing brief pulses of convection on both days So the Question of the Day is if this was a Mesoscale Convective Vortex MCV that was spawned by convection over the tropical Atlantic Ocean and it was found in the Northern Hemisphere then wouldn t such a feature be expected to exhibit a counterclockwise or cyclonic in the Northern Hemisphere rotation The answer to that question provided via email from the bright minds of Brian Etherton at the University of North Carolina at Charlotte and Brad Barrett at the University of Oklahoma since this mesoscale circulation possessed a small radius of curvature implying a large Centrifugal Force and was located near the Equator implying a small Coriolis Force then the flow as governed by the Gradient Wind Balance equation would be cyclostrophic a balance between only the Pressure Gradient Force and the Centrifugal Force so the direction of flow into such a

    Original URL path: http://cimss.ssec.wisc.edu/goes/blog/archives/date/2008/06 (2012-11-14)
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  • May « 2008 « CIMSS Satellite Blog
    16th Annual U S Canada Great Lakes Operation Meteorology Workshop Milwaukee WI Sep 5 7 2007 Posted in Fog detection General interpretation GOES 12 Marine weather MODIS No Comments Severe thunderstorms over the Front Range and the central Plains May 22nd 2008 AWIPS images of the GOES 10 7 µm IR channel above showed the development of severe thunderstorms across parts of Colorado Wyoming Nebraska and Kansas on 22 May 2008 see also CIRA RAMMB Satellite Case Study According to the SPC storm reports a number of tornadoes were produced by these storms one tornado related fatality was reported near Greely Colorado along with large hail up to 2 75 inches in diameter near Windsor Colorado and 3 00 inches in diameter near Grinnell Kansas A closer view using the 1 km resolution MODIS 11 0 µm IR channel above from around 17 57 UTC 11 57 am local time revealed a rather diffuse enhanced v signature just east northeast of Fort Collins Colorado station identifier KFNL This storm went on to produce tornadoes and large hail in southeastern Wyoming with one tornado doing extensive damage in the Laramie area Another MODIS IR image from around 19 34 UTC 1 34 pm local time displayed impressive detail in the overshooting top structure of the storms developing over western Kansas and far southwestern Nebraska below with the coldest cloud top brightness temperatures in the 70º to 80º C range black to while enhancement The GOES sounder derived Convective Available Potential Energy CAPE product below indicated that the pre convective environment across northeastern Colorado during the morning hours was becoming unstable with CAPE values in the 2000 4000 J kg 1 range yellow to red enhancement at 16 00 UTC 10 am local time The air mass south of the warm front and east of the dryline from southern Kansas into Texas was also very unstable with CAPE values in some areas over 4000 J kg 1 purple enhancement Posted in GOES sounder GOES 12 MODIS Severe convection No Comments Vegetation across Southern California May 21st 2008 A comparison of Aqua MODIS true color images from 05 March 2008 and 17 May 2008 above showed the browning of vegetation across Southern California after the Spring season rains 90 day total rainfall 90 day percent of normal rainfall had ended A significant amount of snowmelt was also evident during that period over the southern Sierra Nevada mountains as well as over the higher elevations of smaller ranges such as the San Gabriel San Bernardino and San Jacinto Mountains The images courtesy of Liam Gumley CIMSS were created in Google Earth using publicly available data from the SSEC MODIS Today website Even though the MODIS true color images above suggested an overall dry down of the vegetation across the region a comparison of AWIPS images of the MODIS Normalized Difference Vegetation Index NDVI and visible channel below indicated that many areas of southern California still exhibited a NDVI value as high as 0 5

    Original URL path: http://cimss.ssec.wisc.edu/goes/blog/archives/date/2008/05 (2012-11-14)
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  • April « 2008 « CIMSS Satellite Blog
    streaming northeastward along the Eastern Seaboard during the day helping to provide the necessary moisture for convective development along and ahead of the cold front that was moving eastward through the mid Atlantic states AWIPS image combinations of the DMSP TPW GOES 12 sounder TPW below also show the TPW plume and include an overlay of the GOES derived atmospheric motion vectors These satellite winds showed that a large trough was centered over the southern Great Lakes and Ohio River Valley in addition a diffluent flow pattern within the upper troposphere the 450 275 mb layers green and cyan wind vectors was evident over eastern Virginia This diffluence aloft likely contributed to the creation of an environment that supported large scale ascent favorable for severe thunderstorm development over that particular region during the afternoon hours on 28 April Posted in AVHRR GOES sounder GOES 12 POES Satellite winds Severe convection No Comments Heavy snow in South Dakota and Minnesota April 26th 2008 AWIPS images of the MODIS visible channel 1 6 µm near IR snow ice channel and Land Surface Temperature LST product above depicted a broad swath of heavy snow on the ground across parts of eastern South Dakota and western Minnesota on 26 April 2008 Snowfall amounts included 19 0 inches at Watertown South Dakota which set an all time record for 24 hour snowfall accumulation there and 15 5 inches at Brandon Minnesota On the MODIS visible image the unfrozen lakes stand out as dark features against the bright white snow covered ground the snow cover appears very dark on the MODIS snow ice image since snow is a very strong absorber at the 1 6 µm wavelength in contrast to supercooled water droplet clouds which appear as varying shades of white Note how the MODIS Land Surface Temperature values within the snow swath were in the 30 40º F range green colors compared to much warmer LST values of 50 60º F yellow to orange colors over the bare ground regions on either side of the deep snow cover The MODIS LST product gives an indication of the temperature of the actual land surface or skin temperature which can be several degrees different than the air temperatures measured in instrument shelters located about 5 feet above ground level A MODIS true color image from the SSEC MODIS Today site below viewed using Google Earth further demonstrated the large contrast between the significant snow cover and the surrounding bare ground According to the National Weather Service forecast office at Sioux Falls a Trough of Warm Air Aloft TROWAL contributed to the heavy snow event which forced Interstate 29 to be closed from Brookings about 50 miles north of Sioux Falls all the way to the North Dakota border Posted in Google Earth MODIS Winter weather No Comments Older Entries Webmaster Follow us on Search for Pages About this site CIMSS Satellite Proving Ground Contact us Mobile users POES AVHRR in AWIPS SatePedia Suomi NPP JPSS Proving Ground

    Original URL path: http://cimss.ssec.wisc.edu/goes/blog/archives/date/2008/04 (2012-11-14)
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  • March « 2008 « CIMSS Satellite Blog
    animation of GOES 12 visible images below reveals the power of the late March high sun angle even though surface air temperatures remained in the 30s F some of the bands of fresh snow cover melted very quickly during the morning hours on 28 March Posted in GOES 12 Google Earth MODIS Winter weather No Comments Warm air ahead of a cold frontal boundary March 27th 2008 A cold frontal boundary was moving southward across the central and southern Plains on 27 March 2008 AWIPS images of the MODIS visible channel above showed that the leading edge of the front was generally cloud free as it moved through the Oklahoma and Texas panhandle regions AWIPS images of the GOES 12 3 9µm shortwave IR channel below revealed a well defined warm air wedge darker gray to black colors out ahead of the advancing cold frontal boundary a line of convection was seen to form along the leading edge of the front from eastern Oklahoma into Arkansas and Missouri Also note that there were several hot spots black pixels due to scattered fire activity that was burning briefly across the region winds of 20 40 mph behind the front created an environment favorable for fire growth The effect of this wedge of warm air along and ahead of the cold front was very evident on AWIPS images of the MODIS Land Surface Temperature product below a curved band of warmer land surfaces 100 115º F darker red to black colors showed up over parts of northeastern New Mexico the Texas panhandle and southwestern Oklahoma Note that the MODIS LST values are surface skin temperatures which can be several degrees warmer than the shelter air temperatures which are measured 5 feet above ground level afternoon air temperatures reached 94ºF at Wichita Falls Texas KSPS and 93ºF at Frederick Oklahoma KFDR before the cold front passed those locations Posted in Fire detection GOES 12 MODIS No Comments Older Entries Webmaster Follow us on Search for Pages About this site CIMSS Satellite Proving Ground Contact us Mobile users POES AVHRR in AWIPS SatePedia Suomi NPP JPSS Proving Ground VISIT SHyMet Training Topics March 2008 M T W T F S S Feb Apr 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Categories Air quality Antarctic Arctic AVHRR Aviation AWIPS II Calibration Anomalies Cloud Top Cooling Convective Initiation Fire detection Fog detection General interpretation GOES sounder GOES 10 GOES 11 GOES 12 GOES 13 GOES 14 GOES 15 GOES R Google Earth Heavy rain flooding Historical Hydrology Lightning Marine weather McIDAS V Meteosat MODIS MTSAT Other Satellites POES Red Green Blue RGB images Satellite winds Severe convection Suomi NPP Synthetic satellite imagery Training Tropical cyclones VIIRS Volcanic activity Web Map Server What the heck is this Winter weather Other blogs of interest AccuWeather Blogs CIMSS GOES Gallery CIMSS TPARC Support CIRA GOES

    Original URL path: http://cimss.ssec.wisc.edu/goes/blog/archives/date/2008/03 (2012-11-14)
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  • February « 2008 « CIMSS Satellite Blog
    Sea Surface Temperature product above confirmed the presence of a very sharp SST gradient in that area near 40º N latitude 65º W longitude with a patch of water having SST values in the 40s F cyan to blue enhancement located just to the east of water having SST values in the 60s F green enhancements black features on the SST image are clouds Low level baroclinicity enhanced by the sharp SST gradient was aiding the development and maintenance of the cumulus line as warm air moving eastward encountered the colder pocket of water stratus cloud quickly formed as the marine boundary layer air was rapidly cooled to its dew point Posted in Fog detection GOES 12 Marine weather MODIS No Comments Return flow of moisture from the Gulf of Mexico February 25th 2008 With a dome of high pressure centered over the southeastern US early in the day on 25 February 2008 the Gulf Coast of Texas began to experience a southeasterly onshore flow during the pre dawn hours AWIPS images of the GOES 12 10 7µm IR channel above revealed a subtle signature of slightly warmer cloud top temperatures darker gray enhancements associated with the return flow of fog and stratus as moisture over the Gulf of Mexico began to move inland across Texas The GOES 12 fog stratus product above was better able to detect the inland progression of the leading edge of the fog stratus features darker yellow to orange enhancements as well as the development of separate areas of radiation fog further inland lighter yellow enhancement A new satellite product that has recently been added to AWIPS beginning with Operational Build 8 2 is the GOES Low Cloud Base product above which provides an indicator of whether the base or bottom of a cloud fog feature meets the aviation criteria of Instrument Flight Rules IFR with bases less than 1000 feet above ground level red enhancement or Marginal Visual Flight Rules MVFR with bases greater than 1000 feet but less than 3000 feet above ground level green enhancement or cirrus cloud blue enhancement Note that the GOES Low Cloud Base product is only valid during night time hours this is also true of the GOES fog stratus product due to the fact the the 3 9µm shortwave IR channel used for those satellite products is very sensitive to reflected solar radiation during daylight hours A comparison of the 4 km resolution GOES 12 IR image fog stratus product and low cloud base product with the 1 km resolution MODIS fog stratus product above shows the advantage of better spatial resolution for detecting the leading edge of the inland moving fog stratus features and also for estimating what portions of the areas of fog stratus might be vertically deeper denoted by the darker orange to red enhancements The spatial resolution of the IR channels on the Advanced Baseline Imager ABI instrument aboard the GOES R satellite planned to be launched in 2014 will be 2 km

    Original URL path: http://cimss.ssec.wisc.edu/goes/blog/archives/date/2008/02 (2012-11-14)
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  • January « 2008 « CIMSS Satellite Blog
    northern Minnesota Wisconsin and Michigan this deep snow cover along with cloud free skies and light winds allowed for very strong radiational cooling of the air near the surface A higher resolution 1 km view using the MODIS 11 0µm IR channel and the MODIS fog stratus product below revealed an amazing amount of structure in the surface brightness temperature field over the region much of which was driven by terrain with cold air drainage into low lying areas such as river valleys the coldest MODIS IR brightness temperatures sampled on the AWIPS images were 38ºC in northern Wisconsin and 42ºC in northern Minnesota The MODIS fog stratus product created by computing the 11 0µm 3 7µm brightness temperature difference confirmed that there were no areas of fog or stratus cloud contributing to the interesting IR temperature structure seen across much of the Upper Midwest region around 08 20 UTC 2 20 AM local time Note the appearance of urban heat islands warmer IR temperatures cyan enhancement around cities such as Minneapolis Minnesota and Sioux Falls South Dakota NWS cooperative observer overnight minimum temperatures were as cold as 31ºF 35ºC at Sparta Wisconsin and 39ºF 39ºC at Embarrass Minnesota There was also a reported minimum temperature of 51ºF 46ºC at a Minnesota Department of Transportation site northwest of Duluth below but the temperature data from that particular site appeared to be suspect Such cold temperatures aided in the formation of ice along the near shore waters of western Lake Superior as seen the following afternoon in a 250m resolution MODIS true color image from the MODIS Today site below Lake Superior is the largest and deepest of the Great Lakes and is usually the last to experience significant ice formation during the winter months Posted in Fog detection GOES 12 Marine weather MODIS Winter weather No Comments Swath of snow cover in the Deep South January 20th 2008 A Terra MODIS true color image from the SSEC MODIS Today site above revealed a swath of fresh snow cover across parts of Mississippi Alabama and Georgia on 20 January 2008 Snowfall amounts in the state of Alabama which fell on the previous day were as high as 5 8 inches near Verbena 5 0 inches at Orrville and 4 0 inches at Toxley located on the MODIS imagery using Google Earth below snowfall up to 3 0 inches was reported in Mississippi with 1 5 inches falling in Georgia AWIPS images of the MODIS visible channel the 1 6µm snow ice channel and the Land Surface Temperature product below confirmed that this feature was indeed snow cover snow is a strong absorber at the 1 6µm wavelength and appears darker on the snow ice channel image in addition the land surface temperatures within the area of snow cover were generally several degrees F colder upper 20s to low 30s F darker green enhancement compared to the surrounding areas with bare ground where land surface temperatures were generally in the mid 30s

    Original URL path: http://cimss.ssec.wisc.edu/goes/blog/archives/date/2008/01 (2012-11-14)
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  • December « 2007 « CIMSS Satellite Blog
    somewhat darker satellite scene in those urban areas compared to the adjacent outlying rural areas Also evident on the AVHRR image were well defined lake effect snow bands over Lake Michigan that were moving inland over portions of Michigan and Indiana these snow bands were on the far western periphery of a large winter storm that was centered over the Northeast US MODIS true color imagery from the MODIS Today site above revealed a large number of lake effect snow LES bands over parts of Lake Superior Lake Michigan and Lake Huron as cold arctic air streamed southward across the Great Lakes on 14 December 2007 these LES bands produced 3 6 inches of snowfall at some locations in the Upper Peninsula of Michigan On that same day MODIS imagery farther to the east showed a variety of banded cloud features over the Mid Atlantic states below Posted in AVHRR General interpretation Google Earth MODIS POES Winter weather 1 Comment Snow vs stratus cloud discrimination December 17th 2007 AWIPS images of the MODIS visible and 1 6 µm snow ice channel images from 17 December 2007 above demonstrate the utility of the snow ice channel for helping to identify areas of thin supercooled water droplet stratus clouds that exist over a snow covered satellite scene this MODIS imagery was mentioned in the NWS Milwaukee Sullivan Area Forecast Discussion that afternoon Note the semi transparent nature of many of the stratus cloud patches which allowed surface features such as rivers cities and densely forested areas to be seen on the visible image The GOES 12 sounder Cloud Top Height product below suggested that the tops of the thicker stratus cloud areas located over northern Wisconsin and northern Illinois were 9000 9800 feet above ground level yellow enhancement Surface METAR data under those same cloud features indicated that the cloud bases were only 300 800 feet above ground level so if the stratus clouds were really close to 9000 feet thick it was remarkable to be able to see hints of surface features through such a cloud layer Posted in General interpretation GOES sounder MODIS No Comments Older Entries Webmaster Follow us on Search for Pages About this site CIMSS Satellite Proving Ground Contact us Mobile users POES AVHRR in AWIPS SatePedia Suomi NPP JPSS Proving Ground VISIT SHyMet Training Topics December 2007 M T W T F S S Nov Jan 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Categories Air quality Antarctic Arctic AVHRR Aviation AWIPS II Calibration Anomalies Cloud Top Cooling Convective Initiation Fire detection Fog detection General interpretation GOES sounder GOES 10 GOES 11 GOES 12 GOES 13 GOES 14 GOES 15 GOES R Google Earth Heavy rain flooding Historical Hydrology Lightning Marine weather McIDAS V Meteosat MODIS MTSAT Other Satellites POES Red Green Blue RGB images Satellite winds Severe convection Suomi NPP Synthetic satellite

    Original URL path: http://cimss.ssec.wisc.edu/goes/blog/archives/date/2007/12 (2012-11-14)
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