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.

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The North Atlantic Tropics Looking to become Active Again This Weekend or Next Week

It’s August and with that it’s time for the North Atlantic to show its tropical cyclone “muscle”. Tropical waves become more numerous as mesoscale convective systems form over the tropics of West Africa and race off into the open Atlantic; their mid-level “vorticity” or spin the seed for possible further development. The National Hurricane Center in Miami has pegged one Thursday with an 80% chance of development between now and Tuesday (40% chance between now and Saturday).

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Shortwave infrared image (sometimes known as “nighttime visible”) taken at 8 pm EDT Thursday. This shows a cloud mass moving off West Africa associated with a new tropical wave south of the Cape Verde Islands. (NOAA)

Mid-range models suggest the system will develop possibly into a depression or tropical storm, moving generally westward toward the Lesser Antilles heading toward Tuesday. Much more on what will happen will depend on the system’s development. Mid-level dry air brought in from the Sahara Desert will be an issue for this system as it approaches the Lesser Antilles if it moves north of 15N. As far as upper-level winds, forecast shows a modestly favorable environment for development, but details will wait until down the road. Water temperatures in this part of the Atlantic – known as the Main Development Region (MDR) – are running up to 1.5 C (~3 F) above average with abundant warm sea surface temperatures above 26 C (79 F) west of 35 W.

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Current Sea Surface Temperatures over the tropical Atlantic Ocean. The orange-red and red shades indicate temps at and above 26 degrees C. (Wunderground.com)

Because of the strong semi-permanent “Bermuda High” expected to dominate the Central and Western Atlantic next week, this system will need to be watched by interests in the Western Atlantic Basin for potential impacts in case it does not curve northeastward out to sea because of the subtropical high pressure system to its north (assuming it develops).

Also of interest is a system in the Eastern Caribbean Sea. It is in a more hostile environment (shear and dry air main problems) and only has a 40% chance of development over the next 5 days.

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Shortwave IR image at 8:45 pm EDT showing generally disorganized thunderstorm activity associated with a tropical wave in the Eastern Caribbean. (NOAA)

The Atlantic has been running about a month ahead of schedule on named storms, but has been dead quiet on hurricanes. The 1966-2009 average for the first hurricane in the basin is coming up (August 10th), but given recent years of activity, the Accumulated Cyclone Energy (ACE) thru Aug. 2nd is running at its lowest level in the basin since 2009. But still 90% of the ACE on average occurs from here on out, so much can still happen, especially given the lack of one otherwise major hindering presence in El-Nino.

I’ll keep track of these disturbances in the coming days and have more for you if they develop into organized systems. Stay tuned!

Is it a Heat Wave or a BBQ Pit? Fires Add Smoke to the Misery

It was VERY smoky in the Northwest Wednesday unfortunately because of major fires in the Interior US and Canada.

Satellite image of Washington State showing abundant smoke over much of Puget Sound and the Strait of Juan de Fuca Wednesday.
Photo from Seattle’s Lake Washington of the sunset view Wednesday evening through the thick smoke haze produced from Canadian fires. (Photo by NWS Seattle on Twitter)

BELOW were the highs Wednesday for select cities. Southwest WA and Western OR are being particularly hit hard by this heat wave. Interior Western WA and Puget Sound were actually sparred some of the worst of the heat today by the smoke; it was thick enough to act as a cloud to dampen the radiation and limit warming in places such as Seattle. It remains to be seen if that will be the case Thursday. If not, the hottest day if the heat may very well be Thursday for Western WA (and about the same for Western OR). This, along with an Air Quality Alert in effect for much of Western WA/OR means those in the area will need to not only be careful with strenuous activity to avoid heat-related illnesses, but also avoid breathing problems, if sensitive to such smoke particulates.

(record highs in red)

WASHINGTON

Seattle (National Weather Service Office): 88

Seattle (International Airport): 91 – Old Record 89 (2009). Special Note: Seattle also shattered its daily record for warmest minimum temperature with a morning low of 69 (old record was 61 set back in 2015) and it ranks as the 2nd warmest daily minimum temperature on record.

Olympia: 91

Hoquiam: 89 – Old Record 81 (1993)

Vancouver: 102

Quillayute (North WA Coast): 98 – Old Record 89 (1993). Special Note: This was likely caused by easterly downslope winds; easterly surface winds flowing along the higher hilly terrain descends down the slopes resulting in “adiabatic heating” (compression heating from increasing pressure on the air molecules as the flow drops in elevation). This hot air blows into town and shoots the temperature up fast. This process occurs throughout the region and is the reason why it is typically a “dry heat” in Western WA/OR during heat waves. The heated air becomes dry, with little moisture added to it.

OREGON

Astoria: 93 – Old Record 88 (1939)

Portland (International Airport): 103 – Old Record 96 (1986)

Troutdale (East Portland Metro): 105 – Old Record 99 (1995)

Hillsboro: 105 – Old Record 99 (1939)

Salem: 107 – Old Record 102 (1939)

Eugene: 102 – Old Record 99 (1939)

Medford: 112 – Old Record 105 (1993)

Klamath Falls: 99 – Old Record 94 (1977)

As you see, for Oregon, there was a major theme in the records for Wednesday’s climate stations. It was the hottest day many of these locations had seen on this date since 1939.

Please be safe if you live in this region the next couple of days. Drink PLENTY of water, take breaks from the heat as necessary, use fans if you don’t have air conditioning (common problem in this region, I lived there without air conditioning and the summers statistically are generally getting warmer because of anthropogenic climate change…), and again, like me, I have asthma; if you don’t need to do anything strenuous outside DON’T! Just drive instead of walk or just stay inside, cool and relax. The slightly cooler weather (still above normal, however) starts Friday.

Tropical Storm Emily impacting much of Florida Monday

Tropical Storm Emily formed last night over the eastern Gulf of Mexico.  An area of low pressure developed thunderstorm activity which managed to consolidate and organize as it approached the central gulf coast of Florida overnight. Meteorologists began to notice the increasing organization of the system on local radar and at 6 am EDT this morning, the National Hurricane Center in Miami declared the system “Emily”.

Regional radar showing huge rain extent associated with Emily near and south of the center.
Enhanced infrared image showing cloud temperatures of Emily. Coldest temps (reds) near center along central gulf coast.
 

As an upper atmospheric trough of low pressure digs southeastward from the upper-Midwest over the next 2-3 days, this is expected to steer Emily northeastward. It will move out of Florida by overnight tonight/early Tue and head off into the open waters of the Atlantic well-offshore the East Coast. Land interaction today will weaken it but it may regain some strength over the waters of the Gulf Stream mid-week.

Atlantic tropical cyclone statistics thus far this season: 5 named storms, 0 hurricanes, 0 major hurricanes. On July 31st, on average the Atlantic is expected (based on 1966-2009 data) to have observed only 1 named storm, 0 hurricanes, 0 major hurricanes (on Aug 1st, the average named storms increases to 2). As we go deeper into the month of August expect the hurricane numbers to go up thanks to favorable below average wind shear and above normal oceanic heat content currently in existence in the Main Development Region (MDR) of the Tropical Atlantic. 


This area is largely turned off in earlier months but ramps ups later in the season as tropical waves develop from the tropics of West Africa and moves south and west of the Cape Verde Islands. So the Atlantic still has a lot left in the tank as far as heat energy to release.

Hilary and Irwin making plans for a Fujiwhara waltz over the open ocean

Let’s learn something cool about the tropics!

The past couple of weeks, the Eastern Pacific Basin has been quite active with multiple active tropical cyclones churning, dying and new ones forming. All while the North Atlantic Basin has been largely silent. We’ll get into the pattern set up for tropical activity between the two basins in the coming few weeks in a moment. But first, let’s discuss two interest systems in process in the EPac – Hilary and Irwin.

(Intensities are as of 4 pm CDT Thurs)

Hurricane Hilary is currently a Category 1 with max winds of 75 mph moving to the west-northwest. Meanwhile, ~480 nautical miles southwest of Hilary is Tropical Storm Irwin. It has max winds of 60 mph and drifting westward. Neither system is a threat to populated land masses and both are quickly heading for cooler waters north of the subtropical Pacific, where much drier air also exists in the mid-levels of the atmosphere. Both will lead to rapid deterioration of the cyclones this weekend.

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Visible satellite image showing Tropical Storm Irwin and Hurricane Hilary in close proximity at 4 pm CDT July 27, 2017. Cooler waters are noted to the north producing stable air mass near the sea surface, including deep marine stratus clouds and “closed cell” cumulus cloud deck. Stable air mass is non-conducive for thunderstorms hurricanes need to sustain themselves.
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Same image at same time as above in the “water vapor” infrared channel, where mid-level water vapor is detected. The circled area is a fairly dry area where air is experiencing sinking motions, coinciding with the cooler surface waters and the lack of thunderstorm activity for deep atmospheric moisture. Deep dry air can disrupt thunderstorm activity in tropical cyclones and weaken them.

Later Sunday and into Monday, an amazing phenomenon is expected to occur. Because of the very close proximity of Hilary and Irwin – only several hundred miles apart – the two cyclones are expected to undergo a Fujiwhara Interaction. This describes when two vortices in close proximity begin to rotate around a common center or one around another if one is more dominant. It is named after the Japanese meteorologist Sakuhei Fujiwhara who first described the interaction scientifically in a 1921 paper.

It does not happen very often, but it is typically more common in the Western Pacific basin where a very large surface area of favorable tropical development and maintenance exists and many cyclones can develop simultaneously and sometimes in close proximity.

Numerical models have shown the possible interaction for days.

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The slideshow above displays the Hurricane Weather Research & Forecasting Model forecast initialized at 11 pm PDT Wednesday with the forecast valid 5 pm PDT Sunday – 11 am PDT Monday. This model is “nested” on Hilary to show its evolution (the colors are surface temperatures in degrees C and wind barbs are in knots). However, you can see Irwin orbiting around it on its south and east sides Sunday evening – Monday morning. Irwin will likely weaken and die (along with Hilary, not long after), or will become absorbed by Hilary.

Nature never ceases to amazes in what it can do with the laws of physics!

 

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!