A deepening circulation north of Palau in the western Pacific is projected to intensify into a tropical storm between 3 and 4 February 2026. This system is currently (as of 1600 UTC on 3 Feb 2026) labeled as Invest 94W, but analysis from the Joint Typhoon Warning Center projects intensification into a tropical cyclone. A closer look at satellite products can help inform the discussion of what will happen next. Infrared satellite imagery from Himawari-9’s Advanced Himawai Imager reveals a largely asymmetric circulation between Palau and the Micronesian island of Yap.

It can be hard to identify the center of circulation given upper level divergent flow is at times obscuring the lower level flow. Scatterometry can help clear up the confusion by providing a more easily-discernible view of the ocean surface-level winds. Unfortunately, the center of circulation has slipped through the gaps of the most recent ASCAT overpasses, so the broader but noisier OSCAT-3 winds have to be used instead. Winds appear to be on the order of 30-40 kts at the heart of the circulation.

Of course, warm sea surface temperatures are an important factor in tropical cyclone development. The NOAA Geo-Polar blended SST product is a valuable resource for this. Here, the area surrounding the invest has been circled to aid in location. SSTs are between 28-32 C (82 -90 F) so a substantial amount of latent heat is available for the developing system to access.

Larges amounts of water vapor are present in the atmosphere as well, as seen in the CIMSS MIMIC-TPW2 product. The invest is found between 130 and40 degrees E at 10 degrees N. These satellite-derived total precipitable water values are approaching 70 mm.

The CIMSS Environmental Steering product calculates mean winds over various layers through analysis of satellite-observed motion. For an as-yet weaker system like Invest 94W, the 700-850 hPa mean layer can provide useful insight (stronger cyclones use deeper layers). Here, the steering flow suggests that the system will propagate westward toward the Philippines as time progresses.

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48 hours of 5-minute CONUS Sector GOES-19 (GOES-East) Water Vapor images that included hourly plots of surface weather type (above) showed the development of a winter storm that produced up to 19.5″ of snowfall and wind gusts as high as 64 mph in eastern North Carolina (storm summary) — and even some light snow in far northern Florida — from 30 January to 01 February 2026.

A GOES-19 Mesoscale Domain Sector provided 1-minute imagery of this winter storm — and a closer view centered over eastern North Carolina using Water Vapor and Infrared imagery (below) depicted the formation of west-to-east oriented mesoscale cloud bands which enhanced snowfall rates as they moved northward across eastern North Carolina to southeastern Virginia.

As clouds cleared after the storm moved offshore, GOES-19 True Color RGB images from the CSPP GeoSphere site (below) showed that some of the fresh snow cover across Georgia, South Carolina and North Carolina began to melt during the day on 01 February.

As the low pressure system moved off the US East Coast and rapidly intensified to Hurricane Force, hazy areas seen in GOES-19 True Color RGB images (below) represented enhanced solar reflection off of high waves and sea spray (where strong surface winds were present to the east and southeast of the low center, behind its cold front).

GOES-19 Visible images with plots of Derived Motion Winds (DMW) (below) depicted a large swath of DMW speeds >50 kts (yellow) east and southeast of the Hurricane Force low center. GLM Flash Extent Density also showed that lightning activity was associated with areas of convection near and northeast of the low center.

DMW speeds were as high as 82 kts in the region of the hazy signature east of the low  pressure center (below).

Altimeter significant wave height values east of the Hurricane Force low were as high as 46.13 ft derived from SWOT at 2130 UTC and 50.47 ft derived from AltiKa at 2239 UTC on 01 February (below).

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5-minute CONUS Sector GOES-19 (GOES-East) Visible images (above) showed the development of at least 2 mesolow circulations in southern Lake Superior (off the coast of Upper Michigan) on 29 January 2026. The combination of Fixed Buoy and METAR surface reports implied that there was convergence over the portion of the lake where the mesolows formed. Just west of the mesolows, the peak wind gust at the Stannard Rock buoy (STDM4) was 29 kts at 2100 UTC.

Plots of Metop-B ASCAT surface scatterometer winds valid at 1445 UTC (below) confirmed the presence of mid-lake convergence in the area where the mesolows later developed.

Surface scatterometer winds from Metop-B/C highlighted the mid-lake convergence — while OSCAT-3 winds showed the compact wind circulation associated with development of the first mesolow (below).

Interestingly, GOES-19 GLM data displayed a single lightning flash near the Stannard Rock buoy at 1356 UTC (below), several hours prior to the mesolow development.

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5-minute CONUS Sector GOES-19 (GOES-East) Water Vapor images (above) included hourly plots of surface weather type (R=rain, S=snow, ZR=freezing rain, L=drizzle, F=fog) during the 4-day period (23 January – 26 January 2026) that a major winter storm impacted much of the southern and eastern US. According to the WPC storm summary, some notable storm statistics included: 23″ of snowfall in Pennsylvania, 6.7″ of sleet accumulation in Arkansas and 1.0″ of freezing rain accretion in Louisiana, Mississippi, Alabama and South Carolina. Over 70 storm-related deaths resulted across the affected regions. (The 2025-2026 winter season’s first surface air temperatures in the -40s F within the Lower 48 states occurred north of this winter storm — in northern Minnesota — on 24 January.)

During the day on 26-27 January, as cloud cover cleared in the wake of the departing storm, areas that received significant ice accrual (from freezing rain and/or sleet) showed up as swaths of darker black in GOES-19 Near-Infrared “Snow/Ice” imagery (below) — darker black because ice is a stronger absorber of radiation than snow at the 1.61 µm wavelength. Widespread and long-duration power outages resulted from the weight of ice build-up on power lines.

According to a Storm Total Ice Accumulation analysis (below), the maximum ice accretion amount was 1.24″ just east of Oxford, Mississippi.

On 26-27 January, the areas of significant ice accretion exhibited darker shades of red in GOES-19 Day Snow-Fog RGB images created using Geo2Grid (below) — snow cover appeared as brighter shades of red. The Day Snow-Fog RGB uses the 1.61 µm spectral band as its green component.

The darker appearance of ice accrual (from freezing rain) was first noted on this blog using VIIRS imagery over Oklahoma.

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