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David Helms Profile picture
David Helms
@davidhelms570
Bicyclist, Citizen Ped and Bike Advocate. Retired NOAA and USAF/AFWA (and AWS) meteorologist
Jan 15, 2024 • 6 tweets • 3 min read
1/ Update on river ice conditions on the lower Dnipro near UAF left bank beachhead. Average temperatures in the south have fallen below 0C since 8 JAN, much below 0C after 11 JAN lowering water temps to near 0C and starting river ice growth. Image 2/ Most recent visible imagery: Sentinel-2 (9 JAN) shows dark water indicating unfrozen water w/ no snow cover. LANDSAT8 (11 JAN) shows ice formation in the larger lakes between the Antonovsky Bridges. Ice is definitely forming on the Konka River but not yet on the Dnipro River.
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Nov 19, 2023 • 23 tweets • 12 min read
On 8 NOV 2023, a RF missile struck a Liberian registered commercial ship in Odesa region port. This #NAFOWeather🧵examines why the ship was in Ukrainian port, initial findings on RF weapon used, subsequent data available to confirm initial findings & impact to #UkriCor transits. 2/ Prior to the 24 FEB 2022 full-scale RF invasion, Ukraine exported enough grain to feed 400 million people, most in the famine probe Global South.
topleadprojects.com/environmental-…
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Oct 25, 2023 • 16 tweets • 7 min read
1/ There has been daily reports of clashes near the Antonovsky Rail Bridge crossing of the Dnipro river between Prydniprovs'ke and Poima since 18 October 2023. A #NAFOWeather🧵on the Dnipro wetland ground conditions supporting offensive operations.
Image 2/ First, key dates in this region: Important to note that RF used this location to ferry troops and vehicles in the fall 2022 and UAF has been been attacking RF obn the left bank near the Antonovsky Bridge 6 km downstream of this location in late June 2023. Image
Oct 15, 2023 • 14 tweets • 5 min read
1/ Fall 2023 #MudSeason “bezdorizhzhia (ukr.)/rasputiza" prediction. 15 OCT 2023 Update (version 1!), a #NAFOWeather 🧵 2/ BLUF: Fall 2023 #MudSeason onset will likely be delayed a month due to lower rainfall over east & south Ukraine from AUG thru early OCT 2023. The result of rainfall deficit, along with clear skies & lower humidity increased evaporation caused lower soil moisture than normal. Image
Sep 22, 2023 • 15 tweets • 7 min read
1/ On 17 JUL, Ukrainian #USVs damaged the Kerch vehicle bridge near Tuzla Island. On 3 AUG, Tanker SIG was severely damaged by a #USV while at anchor south of the Kerch bridge. In addition to sinking barges (see below), what has RF done to protect Kerch shipping? A #NAFOWeather🧵 2/ Pictures are today's ship position (mostly at anchor south of the Kerch bridge), the right picture includes the ship track heat map from 2022. Ships that anchored west of Port Taman in 2022 are now gone.
What happened?
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Sep 10, 2023 • 50 tweets • 25 min read
1/ It has been 3 months since the Russians blew-up the Kakhovka HPP dam on 6 June 2023. What is happening to the Dnipro River hydrology and ecology? What are are the options for rebuilding the HPP and possibility for a Dnipro left-bank beachhead? A #NAFOWeather 🧵
Outline: Image 2/ K-HPP Destruction Impacts:
- Irrigation/agricultural land lost: 350,000-550,000 ha
- Drinking (population 700,000) and industrial water loss
- Zaporizhzhia NPP cooling pond water supply loss
- 14,000 homes flooded, many drowned

topleadprojects.com/environmental-…
theguardian.com/world/2023/jun…

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Aug 29, 2023 • 6 tweets • 3 min read
1/ Russians trying to stop ZSU #USV attacks on the Kerch Bridge have built a barrier about 1.2 km long on the Black Sea of the bridge at 45.247362 36.583960.
Left: Sentinel 1 SAR, 27 August 2023
Right: Google map (note traffic backup) from 29 August 2023
goo.gl/maps/5n14pzuuo…

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Image 2/ Sentinel 1 SAR shows #USV barrier getting installed between 19 August and 26 August
Aug 4, 2023 • 10 tweets • 3 min read
1/ Ukrainian Unmanned Surface Vehicles (USV) struck again, this time at Novorossiysk. A summary of USV missions and marine weather for the Novorossiysk mission. A #NAFOWeather 🧵
2/ Since September 2022, Ukrainian USVs have conducted at least 10 missions according to OSINT sources. Most missions have engaged targets during the nighttime, but not all. Most missions engage targets with at least 2 USVs. 4 of the 10 missions have occurred in the past month. Image
Jul 16, 2023 • 12 tweets • 6 min read
1/ A deeper dive regarding the 14 July 2023 fires on the #ZaporizhzhiaNPP cooling pool perimeter fire.
What did @NASA FIRMS see?
4 fire detection grid points from 2 different satellites:
3 from Suomi NPP at 6:41 UTC/4:41L
1 from NOAA-20 at 5:49 UTC/3:49L
https://t.co/AfJzpFJv9x https://t.co/FkFurjDZYZfirms.modaps.eosdis.nasa.gov/map/#t:adv;m:a…

Image 2/ What was going on?
Surface analysis (from @meteoblue) shows(0-5 UTC):
* Winds from 180 degrees (south) at 4-5 m/s
* Relative Humidity: 75%-80%
* Temperature: 18C-20C
* Rain started around 11:00 UTC (after fire detection) Image
Jul 13, 2023 • 8 tweets • 3 min read
1/ TASS was kind enough to provide an ecocide damage assessment of the North Crimean Canal (NCC) in-take at Tavriis'k.
Water stopped flowing into the NCC > month ago, but good to compare ground truth to Sentinel 2 imagery.
#KakhovkaHPP #RussiaBlewTheDam
https://t.co/CZBZ0RJ7Tr



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Image 2/ Sentinel 2 True Color
5 June - 8 July 2023
Jul 11, 2023 • 13 tweets • 6 min read
1/ Are fires becoming more frequent near the Line of Conflict (LoC)? Is shelling the ignition source of these fires? What can we expect in the future? A #NAFOWeather 🧵 2/ Recall @DefMon3 included @NASA FIRMS fire detection points in his LoC updates.
Jun 30, 2023 • 14 tweets • 6 min read
1/ @Michael1Sheldon (Bellingcat) identified a temporary dam built by RF on the Tokmak River south of Tokmak near the P37 highway bridge. Why is RF doing this? A #NAFOWeather 🧵 2/ Several dams have been damaged or destroyed since 24 FEB 2022 by both UAF and RF. In almost every case, the force that damages the dam is retreating. UAF famously destroyed the Irpin River dam on 26 FEB 2022 to stop the RF advance on Kyiv. theguardian.com/environment/20…
Jun 20, 2023 • 35 tweets • 12 min read
1/ Its been 2 weeks since the Russians destroyed the #KakhovkaHPP dam. What will the Dnipro River look like when it returns to its pre-reservoir (before 1955) position? Where are the possible crossing locations? How might UAF exploit these crossing opportunities? A #NAFOWeather🧵 3/ The receding Dnipro RIver has revealed once submerged RF defenses including mines placed along the over 200 km of #KakhovkaReservoir left bank coastline.
Jun 13, 2023 • 7 tweets • 4 min read
1/ Where is the old stream bed of the Konka River at Enerhodar referenced by @energoatom_ua? A #NAFOWeather 🧵
"The Konka River, which now runs along the cooling pond of the ZNPP and was under the Kakhov Reservoir as an underwater current, separated into its historical channel." 2/ Google maps with satellite overlay
goo.gl/maps/TgfHrK3FN… Image
Jun 12, 2023 • 4 tweets • 3 min read
Water access now denied to City of Kryvyi Rih (population 635,000) with Kryvyi Rih canal intake above #KakahovkaReservoir water level.
Sentinel 1 SAR Imagery: 1 and 9 June 2023 (before/after Russian destruction of #KakhovkaHPP).
sentinelshare.page.link/6RD4 Dnipro-Kryvyi Rih Canal [Канал Дніпро-Кривий Ріг; Kanal Dnipro-Kryvyi-Rih].
47.545751 33.937319
goo.gl/maps/26WgWoHud… ImageImage
Jun 12, 2023 • 25 tweets • 15 min read
1/ This thread rebuts claims made by Mikael "Vatnikersson" Valterson against @Ukrhydroenergo, saying Ukraine's state dam operator, "was the original culprit" in destroying the #KakhovkaHPP and exacerbating dam destruction flooding. A #NAFOWeather 🧵 2/ As "Readers" pointed out, the video Vatnikersson used to "prove" Ukraine sent water downstream to #KakhovkaHPP was almost 2 months old. The video proves nothing. Vatnikersson made no attempt to clarify the temporal discrepancy; the tweet is still posted. ImageImage
Jun 10, 2023 • 10 tweets • 6 min read
Sediment has accumulated behind #KakhovkaHPP dam since 1955. Russian destruction of the dam released 18 cubic kilometers of stored water flushing 68 years of sediment into the northwest Black Sea, silting Dnipro harbors and damaging fragile marine ecosystems. ImageImageImageImage Upper Left: Surface Current Direction and Velocity
Upper Right: 5 June - pre-flood
Lower Left: 9 June - Sediment advanced to Odesa
Lower Right: 10 June - Sediment advanced to Choromorsk
Satellite images are from MODIS True Color
go.nasa.gov/3oPRMQH
Jun 5, 2023 • 19 tweets • 9 min read
1/ Soil moisture update: While #MudSeason is "officially over", locally heavy rain can and will degrade trafficability for periods of time. A #NAFOWeather 🧵
2/ BLUF: Updated soil moisture/trafficability matrix similar to 25 April forecast with a 1 month delay in seasonal drying conditions due to above average April rain. Last week of May had several thunderstorm days & locally heavy rain but overall dry conditions since May 1st. ImageImage
Jun 1, 2023 • 26 tweets • 22 min read
1/ I'm supporting @exit266 documenting the Black Sea Grain Initiative #BSGI #BlackSeaGrainInitiative providing marine wx impacting transit & inspection operations. This🧵is a bit off-topic, analyzing weather impact on @CarnivalCruise Sunshine cruise, 21-27 May 2023. 2/ On the evening of 26 May 2023 through mid-day 27 May 2023, the @CarnivalCruise ship #Sunshine experienced high winds and waves on its final leg of 21-27 May 2023 cruise from Charleston, South Carolina to The Bahamas Islands. Cite: @flyerscaptain @CrewCenter @CruiseHive @CNN Image
May 30, 2023 • 9 tweets • 10 min read
#KakhovkaReservoir #KakhovkaHPP
1/ Status Follow-up: 30 May 2023. Over-topping of #KakhovkaHPP dam continues, now occurring for a full month.
2/ Loop of several cloud-free Sentinel-2 passes of #KakhovkaHPP this month, latest 29 May 2023, show white turbulent flow downstream of sluice gates.
May 29, 2023 • 8 tweets • 3 min read
#NAFOWeather 🧵
1/ Weather week in review (23-29 May 2023): Widespread thunderstorms provided significant rain near the Line of Conflict (LoC), with a range of 15-90 mm in the south and 30-100 mm in the east and north. Image 2/ Rainfall from thunderstorms was not uniform with some locations close to the LoC receiving weekly peak total rainfall 80-105 mm including Oleshky, Vuhledar, Bakhmut and Raihorodka. Image