Category Archives: Pacific Northwest

IFR Conditions in Pennsylvania and Oregon

GOES-16 Brightness Temperature Difference (10.3 µm – 3.9 µm) at 0912 UTC on 2 October 2017 over the Mid-Atlantic States (click to enlarge)

GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing.

The images above show the GOES-16 Brightness Temperature Difference at the same time at two places over the United States: The mid-Atlantic States (above) and Oregon and surrounding States (below).  The ‘Fog’ Product, as this Brightness Temperature Difference is commonly called, in reality identifies only clouds that are made up of water droplets — that is, stratus.  A cloud made up of water droplets emits 10.3 µm radiation nearly as a blackbody does. Thus, the computation of Brightness Temperature — which computation assumes a blackbody emission — results is a temperature close to that which might be observed.  In contrast, those water droplets do not emit 3.9 µm radiation as a blackbody would.  Thus, the amount of radiation detected by the satellite is smaller than would be detected if blackbody emissions were occurring, and the computation of blackbody temperature therefore yields a colder temperature, and the brightness temperature difference field, above, will show clouds made up of water droplets as positive, or cyan in the enhancement above.

The River Valleys of the northeast show a very strong signal that suggests Radiation Fog is developing over the relatively warm waters in the Valleys.  The Delaware, Hudson, Mohawk, Connecticut, Susquehanna, Allegheny, Monongahela, and others — all show a signature that one would associate with fog.  A signal is also apparent from southern New Jersey southwestward through the Piedmont of North Carolina.  Would you expect there to be fog there as well, given the signal?

The State of Oregon at the same time shows a very strong signal in the ‘Fog’ Product.  A clue that this might be only stratus, and not visibility-restricting fog, lies in the structure of the clouds — they do not seem to be constrained by topographic features as is common with fog.

GOES-16 Brightness Temperature Difference (10.3 µm – 3.9 µm) at 0912 UTC on 2 October 2017 over Oregon and adjacent States (click to enlarge)

GOES-R IFR Probabilities are computed using Legacy GOES (GOES-13 and GOES-15) and Rapid Refresh model information; Preliminary IFR Probability fields computed with GOES-16 data are available here.  These GOES-16 fields should be available via LDM Request when GOES-16 becomes operational as GOES-East.

GOES-R IFR Probability Fields use both the Brightness Temperature Difference field (10.7 µm – 3.9 µm) from heritage GOES instruments and information about low-level saturation from Rapid Refresh Model output.  The horizontal resolution on GOES-13 and GOES-15 is coarser than on GOES-16 (4 kilometers at the sub-satellite point vs. 2 kilometers), so small river valleys will not be resolved.  (It is also difficult for the Rapid Refresh model to resolve small valleys).

GOES-R IFR Probability fields at 0915 UTC, along with 0900 UTC surface observations of ceilings and visibility (Click to enlarge)

The IFR Probability Fields, above, show some signal over the river valleys of the northeast; that signal is mostly satellite-based, but the poor resolution of GOES-13 means that fog/stratus in the river valleys is not well-resolved. Still, a seasoned forecaster could likely interpret the small signals that are developing to mean fog is in the Valleys.  (And restrictions to ceilings and visibilities are certainly reported in the river valleys of the Mid-Atlantic and Northeast)   IFR Probabilities are also noticeable over southeast Virginia, although widespread surface observations showing IFR Conditions are not present.  (Such observations are somewhat more common near sunrise, at 1130 UTC).

IFR Probabilities are much less widespread over Oregon, with most of the signal over western Oregon related to the topography.  In this example, IFR Probabilities are ably screening out regions where elevated stratus is creating a strong signal for the satellite in the Brightness Temperature Difference field.

What GOES-16 Resolution will bring to IFR Probability

GOES-16 Brightness Temperature Difference field (10.3 µm – 3.9 µm) at 1247 UTC on 5 July 2017 (Click to enlarge)

GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing

GOES-R IFR Probabilities are computed using Legacy GOES (GOES-13 and GOES-15) and Rapid Refresh model information; GOES-16 data will be incorporated into the IFR Probability algorithm in late 2017

GOES-R IFR Probability fields continue to be created using legacy GOES (GOES-13 and GOES-15) data. This is slated to continue through late 2017. The toggle above, over Oregon, hints at how the change in resolution in GOES-16, even far from the sub-satellite point, will likely improve GOES-R IFR Probability performance in regions where topography can constrain low clouds and fog.  The GOES-16 Brightness Temperature Difference field, above, is color enhanced so that positive values (that is, where the brightness temperature at 10.3 µm is warmer than the 3.9 µm brightness temperature, which regions indicate cloud tops composed of water droplets, i.e., stratus) are whitish — and the data shows stratus/fog along the Oregon Coast, with fingers of fog advancing up small valleys.  The image below shows the GOES-R IFR Probability field for the same time (Click here for a toggle).

GOES-R IFR Probability fields show strong probabilities where the Brightness Temperature Difference field above is indicating low clouds.  This is not surprising as the morning fog on this date was not overlain by higher clouds.  However, the resolution inherent in the legacy GOES (inferior resolution compared to GOES-16), shows up plainly as a blocky field.  When GOES-R IFR Probability fields are computed using GOES-16 data, the IFR Probability field resolution will match the GOES-16 resolution.  (Click here for a aviationweather.gov observation of IFR / Low IFR conditions on the morning of 5 July).

GOES-R IFR Probability field computed from GOES-15 data at 1245 UTC on 5 July 2017 (Click to enlarge)

A similar set of figures for California at the same time is below.  The toggle is here, and the aviationweather.gov screen capture is here.

GOES-16 Brightness Temperature Difference field (10.3 µm – 3.9 µm) at 1247 UTC on 5 July 2017 (Click to enlarge)

GOES-R IFR Probability field computed from GOES-15 data at 1245 UTC on 5 July 2017 (Click to enlarge)

 

IFR Probability and Low IFR Probability in the Pacific Northwest

GOES-R IFR Probability fields, hourly from 0300 through 1500 UTC on 4 May 2017 (Click to enlarge)

GOES-R Low IFR Probability fields, hourly from 0300 through 1500 UTC on 4 May 2017 (Click to enlarge)

Note: GOES-R IFR Probabilities are computed using Legacy GOES (GOES-13 and GOES-15) and Rapid Refresh model information; GOES-16 data will be incorporated into the IFR Probability algorithm in late 2017.

Dense fog with IFR and Low IFR Conditions occurred along the Oregon and Washington Coasts early on 4 May 2017. The animations above show the evolution of IFR Probability and Low IFR Probability. Note that IFR Conditions/Low IFR Conditions mostly occurred where Probabilities were high, with a few exceptions (KSMP, Stampede Pass, WA; KKLS, Kelso WA at 1400 UTC). Both IFR and Low IFR Probabilities show a general areal increased between 0800 and 0900; this can be traced to a big increase in the brightness temperature difference that occurred between 0845 and 0900 UTC (shown here) that is likely due to stray light intruding into the satellite detectors. (Brightness Temperature Difference values decreased after 0900 UTC — note that the Brightness Temperature Difference enhancement has color starting when ‘counts’ in the image reach -6).

Low IFR Probabilities do a particularly good job above of outlining the regions of visibility and ceiling restrictions along the coasts of Oregon and of Puget Sound.  Note also that a strip of missing satellite data exists at 1100 UTC over northern Washington.  When satellite data are missing completely, IFR Probabilities are not computed.

A difficulty in using Brightness Temperature Difference fields is shown below. The 1300 and 1400 UTC Brightness Temperature Difference fields show an apparent decrease in low clouds detected as the sun rises (in reality, the amount of reflected 3.9 radiation is increasing as the Sun rises). Fog persists through sunrise as shown in the observations; IFR Probabilities (and Low IFR Probabilities) maintain a signal throughout sunrise.

GOES-15 Brightness Temperature Difference (3.9 µm – 10.7 µm) at 1300 and 1400 UTC on 4 May 2017 followed by GOES-R IFR Probability fields at 1300 and 1400 UTC on 4 May 2017 (Click to enlarge)

Dense Fog in Oregon

GOES-R IFR Probabilities computed with GOES-15 and Rapid Refresh Data, hourly from 0300 through 1400 UTC on 21 December 2016 (Click to enlarge)

Dense Fog developed in the Willamette Valley of western Oregon during the early morning hours of 21 December 2016.  How did GOES-R IFR Probability fields and GOES-15 Brightness Temperature Difference (3.9 µm – 10.7 µm) Fields diagnose this event that led to the issuance of Dense Fog Advisories? The hourly GOES-R IFR Probability animation, above, shows increasing probabilities in the Willamette Valley, starting around Eugene (KEUG) and spreading northward until high probabilities cover the valley by 1400 UTC. IFR Conditions are first reported near Eugene, then through the entire valley by 1400 UTC. Widespread high IFR Probability values are not present elsewhere over Oregon (although they do exist over Washington State, where IFR conditions were also observed).

The Brightness Temperature Difference field (3.9 µm – 10.7 µm), below, shows a different distribution. Early in the animation a strong signal is apparent over much of northern Oregon, and also over the Pacific Ocean. Rapid Refresh output on low-level saturation is used in the GOES-R IFR probability algorithm to screen out regions where stratus that is detected by the satellite likely is not extending down to the surface — over the ocean, for example (coastal sites do not show IFR Conditions), or over much of eastern Oregon/Washington.   Brightness Temperature Difference fields do eventually highlight the presence of fog in the Willamette Valley, but considerable regions outside the valley have a strong return and no indication of IFR conditions.

GOES-15 Brightness Temperature Difference (3.9 µm – 10.7 µm) fields, 0300-1300 on 21 December 2016 (Click to enlarge)

GOES-R IFR Probability fields will frequently (and correctly) screen out regions of strong returns in the Brightness Temperature Difference fields that do not correspond to surface obscuration of visibility and/or low ceilings.

It is possible to alter the Brightness Temperature Difference Colormap, as below (animation courtesy Mike Stavish, SOO at Medford) to better highlight regions of fog in this case.  Note in this enhancement the cirrus clouds appear white, rather than dark, as well.

GOES-15 Brightness Temperature Difference  (3.9 µm – 10.7 µm) Fields, hourly from 0800 to 1400 UTC on 21 December 2016 (Click to enlarge)

The toggle below shows two color enhancements at 1200 UTC: the default version with many orange pixels, and an altered version that shows fewer pixels, mostly in regions where fog is present. A similar toggle for 0400 UTC is here.

Brightness Temperature Difference (3.9 µm – 10.7 µm) fields at 1200 UTC with two different enhancements. (Click to enlarge)

The Challenge of Satellite Fog Detection at Very Small Scales

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Hazards as depicted by http://weather.gov front page at 1400 UTC on 10 November 2016 (Click to enlarge)

Isolated regions of dense fog developed over eastern Oregon early in the morning on 10 November 2016, and one county — around Baker City — was placed in a Dense Fog advisory (Counties in the Willamette Valley of western Oregon, and near Glacier Park in Montana were placed under Dense Fog Advisories a bit later in the morning on 10 November). Click here to see a 1400 UTC mapping of IFR/LIFR conditions from the Aviation Weather Center.

URGENT – WEATHER MESSAGE
NATIONAL WEATHER SERVICE BOISE ID
600 AM MST THU NOV 10 2016

ORZ062-101800-
/O.NEW.KBOI.FG.Y.0012.161110T1300Z-161110T1800Z/
BAKER COUNTY-
500 AM PST THU NOV 10 2016

…DENSE FOG ADVISORY IN EFFECT UNTIL 10 AM PST THIS MORNING…

THE NATIONAL WEATHER SERVICE IN BOISE HAS ISSUED A DENSE FOG
ADVISORY…WHICH IS IN EFFECT UNTIL 10 AM PST THIS MORNING.

* VISIBILITY…ONE QUARTER MILE OR LESS.

* IMPACTS…TRAVEL HAZARD DUE TO POOR VISIBILITY…ESPECIALLY
ALONG INTERSTATE 84 BETWEEN BAKER CITY AND NORTH POWDER

PRECAUTIONARY/PREPAREDNESS ACTIONS…

A DENSE FOG ADVISORY MEANS VISIBILITIES WILL FREQUENTLY BE
REDUCED TO LESS THAN ONE QUARTER MILE. IF DRIVING…SLOW DOWN…
USE YOUR HEADLIGHTS…AND LEAVE PLENTY OF DISTANCE AHEAD OF YOU.

&&

$$

What kind of Fog-detection products are available to assist a forecaster in seeing at a glance that fog is developing? How useful are they for small-scale features such as that in Baker County Oregon?

Brightness Temperature Difference Fields (3.9 µm – 10.7 µm) have historically been used to detect fog; the difference field keys on the Emissivity Differences that exist in water-based cloud droplets: they do not emit 3.9 µm radiation as a blackbody, but do emit 10.7 µm radiation more nearly as a blackbody, so computed brightness temperatures are different: cooler at 3.9 µm than at 10.7 µm. The Brightness Temperature Difference fields for 0900 and 1200 UTC are shown below (Note the seam — GOES-13 data are used east of the seam, GOES-15 data are used to the west). There is no distinct signal over Baker County, nor any pattern that can really help identify regions of fog. Cirrus is present over western Oregon (depicted as dark grey or black in this enhancement); satellite-only detection of low fog is not possible if cirrus prevents a view of the surface.

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GOES Brightness Temperature Difference Fields (3.9 µm – 10.7 µm) at 0900 and 1200 UTC on 10 November 2016 (Click to enlarge)

For a small-scale event, the nominal 4-km pixel size on GOES-15 and GOES-13 (a size that is closer to 6-7 km over Oregon because of the distance from the sub-satellite point) may prevent satellite detection of developing fog. The toggle below shows Brightness Temperature Difference fields at 0928 UTC from MODIS on Aqua, as well as the GOES-R IFR Probability fields computed using the MODIS data.  As with GOES data, the presence of cirrus in the Brightness Temperature Difference field is obvious and shown by a black enhancement.  Little signal is present over Baker County.  (There is a strong signal, however, in the valleys of northwest Montana and northern Idaho — compare this to the GOES-based brightness temperature difference above).

Note:  MODIS resolution is 1-km;  data from the Advanced Baseline Imager (ABI) on GOES-R will have nominal 2-km resolution at the sub-satellite point.

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MODIS Brightness Temperature Difference fields (3.7 µm – 11 µm) and MODIS-based GOES-R IFR Probability, 0928 UTC on 10 November 2016 (Click to enlarge)

What does the GOES-based GOES-R IFR Probability field show during the early morning hours of 10 November? The animation below, from 0800-1200 UTC, shows some returns in/around Baker County. It would have been difficult to use this product alone to diagnose this fog feature however. (It did do a better job of diagnosing the presence of fog over northwest Montana and western Oregon where Advisories were later issued).

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GOES-R IFR Probability fields, hourly from 0800 – 1200 UTC on 10 November 2016 (Click to enlarge)

Small-scale Fog Event near Puget Sound

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GOES-R IFR Probabilities computed with GOES-15 and Rapid Refresh Data, 1100-2200 UTC on 9 February 2016 (Click to enlarge)

GOES-R IFR probabilities on Tuesday 9 February captured the development of a small-scale fog event in/around the southern part of Puget Sound in Washington State. The animation above shows high IFR Probabilities developing shortly before sunrise and persisting through most of the day in a region including Shelton, Olympia, Tacoma and Seattle.

MODIS visible data, below, from the Terra Satellite overpass shortly after 1800 UTC, below, shows the fogbank over the most of Puget Sound, extending inland only over the southern part of the sound.

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MODIS Visible Imagery (0.65 µm), 1822 UTC on 9 February (Click to enlarge)

Suomi NPP viewed Puget Sound on two consecutive overpasses on 9 February, and visible imagery from those passes, just before 2000 UTC and near 2130 UTC, are shown below.  Fog Dissipation is apparent in the later image, which is consistent with the animation of IFR Probability at the top of this post, which animation shows IFR Probabilities declining in value after 2100 UTC.

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Suomi NPP Visible Imagery (0.64 µm), 1953 and 2122 UTC on 9 February (Click to enlarge)

Fog and Low Stratus in Idaho’s Snake River Valley

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GOES-R IFR Probability, hourly from 0500 through 1500 on 8 February 2016 (Click to enlarge)

River Valleys will be prone to fog when they are capped by strong High Pressure, as occurred early in the morning on 8 February 2016 over Idaho. The animations, above and below, show GOES-R IFR Probability fields and GOES Brightness Temperature Difference Fields, respectively. GOES-R IFR Probability fields include information from the Rapid Refresh about near-surface saturation. Compare IFR Probabilities at Burley Municipal Airport (KBYI) in Cassia County with those at Jerome County Airport (KJER) between 0800 and 1100 UTC, when visibilities and ceilings at the two airports vary. IFR Probabilities in general are higher when reported ceilings and visibilities are consistent with IFR conditions, and they are lower when IFR conditions are not reported.

Extensive mid-level stratus over the eastern portions of northern Idaho and western Montana have reduced values of IFR Probabilities (compared to the Snake River Valley where IFR Probabilities are large). This is a benefit of a fused product: Information from two sources combined is more powerful than either of the two sources individually. IFR Probability fields also have superior results when mid-level or higher clouds overspread an area. This occurs around 1200-1300 UTC over the northeastern portion of the Snake River Canyon around Rexburg and Idaho Falls, locations that maintain IFR (or near-IFR) conditions although the brightness temperature difference field has little signal. IFR Probabilities remain enhanced in the region, however, with a signal — a less pixelated, flatter field — that suggests only Rapid Refresh Data are being used as predictors of IFR.

BTD-0500_1500anim_08feb2016

GOES Brightness Temperature Difference (10.7µm – 3.9µm), hourly from 0500 through 1500 on 8 February 2016 (Click to enlarge)

Fog vs. Stratus over the Pacific Northwest

Brightness Temperature Difference (10.7 µm – 3.9 µm) from GOES highlight regions of water-based clouds:  water-based clouds emit 10.7 µm radiation nearly as a blackbody does, but those clouds do not emit 3.9 µm radiation as a blackbody.  Thus, the brightness temperature computed from the radiation detected by the satellite (GOES-15 in this case) — a computation that assumes a blackbody emission — is relatively cooler for the 3.9 µm data compared to the 10.7 µm data.  A water-based cloud is normally stratus, and the pertinent question for aviation purposes (for example) is:  Is the ceiling of that cloud near the surface?  (That is:  Is the stratus also a fog bank, or is it “just” mid-level stratus?)

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GOES-15 Brightness Temperature Difference (10.7 µm – 3.9 µm) and GOES-based GOES-R IFR Probabilities, 0500 UTC 15 December 2015 (Click to enlarge)

The toggles above (0500 UTC) and below (0900 UTC) show how the GOES-R IFR Probability fields capably screen out many regions of mid-level stratus. This is achieved by fusing the brightness temperature difference information with data from the Rapid Refresh Model. If the lowest 1000 feet of the Rapid Refresh Model is not near saturation, probabilities of IFR conditions are reduced.

GOESIFRP_BTD_15December2015_0900UTCtoggle

As above, but at 0900 UTC 15 December 2015 (click to enlarge)

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As above, but at 1200 UTC 15 December 2015 (click to enlarge)

Toggles from 1200 UTC (above) and 1400 UTC (below) continue to show IFR Conditions mostly confined to regions near the Willamette Valley in eastern Oregon — banked up against the higher terrain to the east of the Willamette, and also over the higher terrain of northeastern Oregon (Click here for a toggle between the 1400 UTC IFR Probability field and Topography). IFR Conditions are a function of ceilings above ground (not above Mean Sea Level), so it’s important to recognize the influence of topographic features on an IFR Probability field. Fog/Low stratus can bank up against a topographic feature, and/or it can shroud the top of a topographic feature.

Note also how at 1400 UTC high clouds have impinged upon extreme northwest Oregon and coastal western Washington. In these regions IFR conditions nevertheless persist under the high clouds, but satellite data alone does not indicate low cloudiness. In this region, the inclusion of Rapid Refresh data in the GOES-R IFR Probability algorithm allows the IFR Probability field to continue to provide useful information about the presence of fog/low stratus.

GOESIFRP_BTD_15December2015_1400UTCtoggle

As above, but at 1400 UTC 15 December 2015 (click to enlarge)

MODIS and Suomi NPP afforded high-resolution images of the fog/stratus banks over the Pacific Northwest on 15 December. The brightness temperature difference fields and MODIS-based IFR Probability fields from MODIS at 0533 and 0945 UTC, below, support the observations from the coarser-resolution GOES fields above.

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As above, but for MODIS data at 0533 UTC 15 December 2015 (click to enlarge)

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As above, but for MODIS data at 0945 UTC 15 December 2015 (click to enlarge)

GOES-R IFR Probability fields are not yet computed using data from the Suomi NPP Satellite, but the Day Night band and the Brightness Temperature Difference field give information about the presence of cloudiness. For the case of Suomi NPP data, however, it’s more important to consider surface-based observations to confirm regions of low clouds/fog or mid-level stratus. Note also that December 15 was shortly after a New Moon, and the crescent moon that could give illumination was below the horizon (that is, it had set) at 0918 and 1059 UTC.

Note that Suomi NPP Near-Constant Contrast Day Night Band imagery was scheduled to start flowing in to AWIPS II on 14 December 2015 via the SBN. It should be available in NWS offices now.

SNPPBTD_DNB_15December2015_0918UTCtoggle

Suomi NPP Day Night Band Visible Imagery (0.70 µm) and Brightness Temperature Difference (10.35 µm – 3.74 µm), 0918 UTC 15 December 2015 (Click to enlarge)

SNPPBTD_DNB_15December2015_1059UTCtoggle

Suomi NPP Day Night Band Visible Imagery (0.70 µm) and Brightness Temperature Difference (10.35 µm – 3.74 µm), 1059 UTC 15 December 2015 (Click to enlarge)

Resolution Benefits from MODIS

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GOES-R IFR Probability fields, every 2 hours from 0200 through 1400 UTC on 16 October 2015 (Click to enlarge)

The GOES-R IFR Probability fields over Oregon and Washington on the morning of 16 October 2015 correctly diagnose low ceilings and reduced visibilities along the coast, even when high clouds intervene at the end of the animation above (especially evident at 1300 UTC, below). In addition to marine stratus that is reducing visibility/ceilings along the coast, surface observations suggest a valley fog is forming in/around Centralia/Chehalis Washington (KCLS). However, GOES-based IFR Probability fields do not become enhanced in that area. Why not?

GOES_IFR_16Oct_1300

GOES-R IFR Probability computed from GOES-15, 1300 UTC on 16 October 2015. Note the Character of the field near Newport OR (KONP); the uniformity of the field is characteristic of regions where satellite signals cannot be used because of high clouds (Click to enlarge)

The valley of the Chehalis River, in which the fog is forming, is far too narrow to be resolved by GOES-15, which satellite has 4-km pixel sizes at the sub-satellite point. (Pixels are closer to 6 km in size over southern Washington). Higher-resolution MODIS data (with a 1-km pixel size) can be used to create GOES-R IFR Probabilities, and MODIS overpasses viewed Centralia/Chehalis at 0650, 0924 and 1105 UTC. The imagery below toggles between MODIS-based and GOES-based GOES-R IFR Probabilities at those times.  Even as early as 0645 UTC, the MODIS-based IFR Probability fields are suggesting that a fog is starting to develop.  At later times the MODIS-based IFR Probability values are much larger than the GOES-based values.  MODIS data can give an early alert to the development of small-scale fog.

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MODIS-based (0650 UTC) and GOES-15-based (0645 UTC) GOES-R IFR Probability fields (Click to enlarge)

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MODIS-based (0924 UTC) and GOES-15-based (0930 UTC) GOES-R IFR Probability fields (Click to enlarge)

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MODIS-based (1105 UTC) and GOES-15-based (1100 UTC) GOES-R IFR Probability fields (Click to enlarge)

Fog/Low Stratus over coastal Oregon

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Suomi NPP Visible Imagery from the Day Night Band, 0944 and 1125 UTC on 30 September 2015 (Click to enlarge)

The near-Full Moon provided ample illumination of fog/low stratus near the Oregon Coast early in the morning of 30 September, as shown above. Note also the clear skies near North Bend along the southern Oregon coast. What did the GOES-R IFR Probability field show at these two times?  IFR Probability fields also suggest clear skies around North Bend/Coos Bay (and offshore), as observed.  The fine fingers of fog/low stratus that are moving up river valleys in the 1125 UTC image most notably are not resolved by GOES-15 (which has a 4-km pixel size at the sub-satellite point). Both fields do capture the slow increase in cloud cover over land. Available surface observations show near-IFR conditions at some stations in Oregon.

GOES15_IFRPROB_30Sep2015_0944_1115anim

GOES-R IFR Probabilities computed with GOES-15 and Rapid Refresh Data, 0945 and 1115 UTC on 30 September 2015 (Click to enlarge)