Category 1 Hurricane Franklin making landfall on the East Coast of Mexico

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Hurricane Franklin is making landfall on the East Coast of Mexico Wednesday night/early Thursday morning (~midnight CDT Thursday) with maximum sustained winds of 85 mph with gusts likely over 100 mph. Besides damaging wind gusts, very heavy rain – up to a foot or more – will be possible in the mountainous terrain once the system moves inland and weakens during the day Thursday.  Life threatening flash flooding and mudslides will be the greatest threats to any populated mountain areas (storm surge will be the hazard for coastal areas in the hurricane warning area tonight).


NOAA Raises North Atlantic Tropical Activity Forecast

The National Oceanographic and Atmospheric Administration raised its confidence today that the North Atlantic Basin would have an “very active” season. They called for 14-19 named storms, 5-9 hurricanes, 2-5 major hurricanes. A normal season averages 11 named storms, 6 hurricanes, 2 major hurricanes.

The reasoning for this activity forecast include 1) No El-Nino in the Eastern Pacific which would otherwise produce unfavorable vertical wind shear and cooler sea surface temperatures in the North Atlantic 2) Above normal sea surface temperatures across the Caribbean, Gulf of Mexico and Main Development Region (open tropical Atlantic) 3) The continuation of the Atlantic Multidecadal Oscillation favoring above normal oceanic heat content.

So far, we are at 6 named storms, 1 hurricane, 0 major hurricanes (assuming no surprise intensification of Franklin prior to landfall).

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Tropical Storm Franklin moving over the Yucatan Peninsula this afternoon

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Tropical Storm Franklin made landfall last night near Pulticub, Mexico at approximately 10:45 pm CDT with maximum sustained winds near 60 mph.  Since last night, the system has continued to move over land, remaining fairly well-organized but has weakened some thanks to land interaction with maximum sustained winds now down to 45 mph as of 10 am CDT. However, the National Hurricane Center in Miami anticipates re-strengthening after it enters the Bay of Campeche tonight. The waters in the Bay are piping HOT – 30-32 degrees C (88-90 degrees). These waters are fuel for robust intensification. With that said, northerly wind shear over the Bay is expected to impact Franklin during the day Wednesday as it heads for mainland Mexico, limiting rapid intensification. However, it could be a 70-75 mph tropical storm/Category 1 hurricane when it makes its expected landfall late Wed night/early Thursday morning. If Franklin becomes the first hurricane of the season tomorrow, it would do so around the climatological average time for the North Atlantic Basin (1966-2009) of August 10th. A tropical storm warning and hurricane watch is in effect for the expected landfall region.

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After landfall, there is expected to be 8-12+ inches of rain over the mountainous terrain of Eastern Mexico. Flash flooding and life-threatening landslides are likely.

For those curious and who watch the tropics, you might have been tracking this system since it left West Africa last week.

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Models have continuously wanted to make something of it but of course as it goes, when it comes to tropical cyclones, until it actually develops, the evolution of the system is difficult for numerical models to pin down. This system is no different. However, the wave still has some cohesive structure and therefore potential in the next 5 days to develop into a tropical cyclone as it moves east-northeastward over the open Atlantic. As long as computer models continue to give the wave an opportunity to develop, it is worth watching.

August 21, 2017 Eclipse is on its way! What to expect?

We’re now less than four weeks away from the historic total solar eclipse of August 21, 2017! This will be the first total solar eclipse in the contiguous United States since February 1979 when a total eclipse swept through northern Oregon, southern Washington, into Idaho, Montana and the Canadian Prairies. Much of the Northwest dealt with clouds in the coastal and western regions as cities such as Portland fell into a post-sunrise darkness.

Well now it’s 2017 and this eclipse is in a much better month…August. While this doesn’t guarantee good weather for any location along the path of totality; convection (thunderstorms) and cloud debris can cause issues on the Plains, while marine clouds can cause problems in the Pacific Northwest for example, generally quieter conditions with the jet stream and the domination of summer time high pressure and upper-air subsidence across the continent during the late summer means more opportunity for less cloud cover and quieter conditions across more parts of the country to view the eclipse in August than, say February.

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Path of umbra (inner lunar shadow) where totality will be observed as well as coverage of penumbra (outer shadow) where ONLY partial eclipse will be observed. The center line of the umbra will reach the Oregon Coast at ~17:16 UTC (1:16 pm EDT) moving at 2,416 mph and exit the South Carolina Coast at ~18:49 UTC (2:49 pm EDT) moving at 1,489 mph. ( map found on Wikipedia)
In order to assess the the most important aspect of observing an eclipse – sky conditions – the University of Idaho School of Natural Resources performed a climate analysis for the United States to determine the probability that a location will have clear skies at 10:30 am local time on August 21st. This time is picked because of the arrival of totality on the West Coast.

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Clear Sky Probability for the contiguous United States for 10:30 am local time August 21st. High probabilities are over portsions of the Western US, minus Western WA/OR and CA valleys where morning low marine clouds can occur. (U of Idaho College of Natural Resources)
While clear skies would be absolutely optimal for an eclipse, ESPECIALLY totality,  few to scattered cloud coverage (25-50%), while less fortunate in terms of direct solar photography and SAFE solar viewing, can still yield interesting observations leading up to and during totality. Because the umbra is quite thin, interesting atmospheric optics can occur. Although the area under totality becomes relatively dark, the light outside of the shadow can still be seen to observers. And the reflected light will appear to be twilight-like in color and glow. You could call it “eclipse twilight”. And with any cloud in the area, they will change colors or change in reflection of light as the darkness rolls over them, great for photographic and video effect. Just before totality, the sun itself will start to appear as if it’s “dying” in the final minute or two and the shadow will start to rapidly advance out of the western sky like a monster storm…except it’s not a storm 😀

In addition, regardless of scattered or no clouds, in the last min or so before (and after) totality, if you look at plain surfaces you may witness wavy motions like those in water known as shadow bands. These form as the focused, but rapidly weakening light of the sun is being distorted by the dense atmosphere of Earth. Those very near the totality path may also witness them.

This YouTube video I found some weeks ago shows both the prominent shadow bands and the “eclipse twilight” with clouds.

Now I’m a meteorologist. So when we talk about having a giant astronomical object blasting a shadow across a continent at 2000 mph and putting regions into nighttime in the middle of the day, a meteorologist is going to ask, how is this going to impact the weather?

For those at 75% percent partial eclipse and higher, the surface temperature will start to become depressed temporarily as the incoming solar radiation is reduced. This will be especially apparent for eclipses during the midday. As totality approaches, any winds may calm as a result of “fair weather convection” weakening as surface heating completely shuts down (this is where upward vertical motions produced by surface heating, leading to local winds die down).

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Here’s an EXCELLENT website using a Google Map layout where you can click on a location for eclipse “contact” times (start of partial, start and end of totality, end of partial) and maximum obscuration of the solar disk (areal coverage by the moon): HERE

In a couple weeks, numerical models will START to give us some distant idea of how the weather patterns may evolve for August 21st. I’m especially interested, because my location (Lincoln, NE) WILL experience totality. Will likely head to the south side of town to experience roughly 1 min 45 seconds of it and some of the very partial eclipse before that. It would be my first total solar eclipse since I was born and raised in Seattle but that event didn’t happen there and happened 5 yrs before I was born anyways.

Stay tuned in the coming weeks as weather updates come!

 

Northern Plains becoming hard hit by severe to extreme drought

The Northern US Great Plains into the southern Canadian Prairies are suffering from a growing drought problem. The National Drought Mitigation Center at the University of Nebraska-Lincoln released their weekly drought monitor which updates on the drought situation for the entire country (every Thursday based on Tuesday data). Drought overall across the United States has begun to grow in coverage and intensity. This can happen just from the local abnormalities in a summer season. However, a persistent pattern of dryness has developed over the Northern Plains beginning in May where significantly below normal rainfall has caused soils and hydrologic sources to begin to dry out.

I took a look at some meteorological stations for their recent climate records. Rapid City, SD (currently in the moderate drought zone) is running 3.37 inches below normal in rainfall for the May 1st-July 21st period. In Bismarck, ND (in severe drought) is even worse at 4.01 inches below normal for the same period. May dryness hit the region hard with a major monthly deficit then it simply continued into the summer. At least moderate drought covers ~28% of the above region (ND, SD, NE, KS, WY, CO). Moderate conditions can result in some damage to crops and reduction in stream/river flows and lowering of lake levels. Extreme – which now exists in spots of southwest ND – can mean widespread and devastating agricultural losses and severe reductions in hydrologic sources.

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Above average temperatures likely over the Great Plains (and rest of the country) over the next 3 months. (Climate Prediction Center)
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Meanwhile, there are equal chances (~33% each) for above, near, or below normal precipitation during the same 3 month period. (Climate Prediction Center).

Obviously, “equal chances”- which is based on the expected evolution of various climate patterns – means that there could very well be above average rainfall, which the region really needs at this point to get out of the growing deficit. However, if it ends up being near-normal, they may continue to simply lag behind with similarly bad impacts. Below normal means a worsening and spreading of drought conditions and further difficulty removing the existing drought (anyone remember the difficulty California had in getting out of drought?). Folks in these areas should be prepared for any further water restrictions and do what they can now to conserve in case the dryness lasts longer than expected.

Elsewhere, dryness and moderate drought has begun to spread into parts of the Intermountain West and Four Corners.


Quick update from the Eastern Pacific tropics…new tropical depression! Tropical Depression Ten-E is rolling around between Tropical Storm Greg and TD Nine-E. It’s expected to become a tropical storm in the coming days as it generally moves westward over the open ocean. So there are now 4 existing cyclones in the tropical North Pacific east of 180 longitude. Although Fernanda is dying quickly over cooler waters and dry mid-level air and will likely dissipate by tomorrow.

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Good weekend to you all!