It’s not a dry heat

So there’s one or two heat warnings and advisories up this morning …

(in red, click to embiggen; blue stuff are flood, fog, or coastal advisories)

… and a lot of talk about the Heat Index. Let’s take a closer look. First off while the temperatures are above normal, at least here in coastal GA/SC they won’t be threatening the historical record highs. The air temperatures are going to be high Friday/Saturday, but won’t set any records. The average for July 30th is 92, the records this time of year are over 100 (101-103), and forecast highs in downtown Savannah are 97 today and 96 Saturday. The problem is that humidity is way above normal. That is due to the pattern of air flow over the region is keeping moist Gulf and Atlantic air “trapped” over us (recall the low pressure system that NHC was looking at earlier this week, AL90, wandered over us, then off of North Florida before drifting back over us). And it’s the humidity that’s the problem.

The Heat Index has an interesting history, and there are several versions. The method currently in use by the US National Weather Service is not a complex equation, if you want to see it look here:

  The TLDR is that the “heat index” is supposed to represent how hot if feels, given that the higher the humidity, it “feels” hotter because your body can’t cool itself as efficiently.  The technical reason is because we cool ourselves by sweating (ewww), and the evaporation of that sweat cools us down, since it takes energy – heat – to convert water from the liquid to gas states.  The evaporation rate depends temperature and humidity – the higher the humidity, the less moisture evaporates, and the less heat is transferred from your body to its surroundings. Drier air means that evaporation works better, so it “feels” cooler (although that can be misleading), thus all the jokes about a Dry Heat …

You can’t talk about heat without quoting Hicks πŸ˜›

  Either way, especially if you are not adapted to it, the heat can be dangerous (and in the ranges expected today, even if you are). By the way, the NWS has different criteria for when to issue heat advisories around the country, depending on normals. So a heat advisory in Vermont is issued at much “cooler” temperatures than in Savannah.

Β To sum up, technically speaking, it’s not that it’s so hot, it’s because it’s kinda hot and really humid … it would be uncomfortable at 97, but all that humidity today will make it feel like it’s well over 110, maybe as high as 120 in parts of town where the temperature and humidity gang up.Β  So if you can avoid working outside this afternoon, don’t, and if you absolutely have to, drink lots of fluids, protect yourself, and be careful.

Update: at 2:30pm, in midtown Savannah the air temperature was 93, the humidity 70%, which adds up to a heat index of 120F :O

#Olympics storm update, AL90

Tropical Storm Nepartak took an unexpected turn to the south and intensified yesterday, but then turned back towards the northwest and aside from the jog in the track is still headed to make landfall near Sendai. But it remains a diffuse weak tropical storm, and in one sense impacts should be minimal. Well, except for that Olympics thing. Pink balloons are the venues …

click to embiggen.

Of course this has made outdoor events messy. Was watching the Women’s triathlon yesterday with the athletes running in the rain, which was probably better for them than the higher than normal temperatures over the last few days. Things should clear out tonight (Tokyo time) and be relatively rain free on the back side of the system.

As for AL90, it is currently just inland over coastal Georgia, such as it is. NHC is still marking it with a 10% chance of formation, mostly to cover the small possibility that a circulation center will drift or form over the Gulf Stream and meet the minimal requirements for a tropical system, and given them something to do. I’m not that worried about it.

Elsewhere, in the Atlantic nothing of potential with the dust and unfavorable winds inhibiting formation. There are three invest areas in the east and central Pacific, none near land. So I guess I’ll have to post something in the next day or so about the extreme temperatures and climate, and that’s gonna annoy about half or more of potential readers πŸ˜›

#Olympics #Typhoon, #Georgia Depressed (AL90)?

Tropical Storm Nepartak (WP112021) continues to threaten the Tokyo Olympics, although it’s mostly going to be a messy inconvenience for outdoor events rather than any serious threat. It’s unlikely any areas will experience even tropical storm force winds, much less typhoon (hurricane) conditions. Here’s the swath, this time coded with intensity:

click to embiggen.

The main risk is heavy downpours, which look to persist for several days as the storm stalls in the Sea of Japan.

The low pressure system off the northeastern coast of Florida (NOT a tropical wave, as one local weather dude kept saying last night) will continue to drift inland over Georgia today. NHC still has it tagged with a 30% chance of forming a depression as some convection might flare as it crosses the Gulf Stream, but that becomes doubtful as every hour goes by. That doesn’t mean the Northeast Florida/Georgia/South Carolina Low country won’t get some heavy rain in places and maybe a few wind gusts. Here’s the GFS forecast for mid-day today; it looks like most of the rain will be confined to right along the coast, and showers are already moving inshore as of 6:30am:

Sunday Morning TC Update: #Shanghai #China, #Olympics, #Florida

Of the three tropical cyclone (hurricane) threats, only one is serious at the moment. Typhoon In-Fa has made landfall just south of Shanghai, placing over 114 Million people in tropical storm conditions. Here’s the damage swath:

click any image to embiggen.

It’s always tricky to estimate damages in China due to currency and purchasing power conversion issues. Juggling all the numbers on estimated infrastructure, etc. we get about $2 Billion US Dollars. I suspect that it’s probably higher than that, more like the equivalent of a $5 Billion event for the US.

The second event is tropical storm Nepartak. It’s forecast to be a minimal storm, and ordinarily wouldn’t merit much comment, but it is on track to pass over Japan in the next three days – right in the middle of the Olympics people are starting to call “cursed.” Hopefully it won’t be too disruptive – the winds will be minimal across most of the country. The biggest problems will be heavy rain across Northern Japan. There are only two areas of concern, Miyagi Stadium and Sapporo Dome, both football venues. Hopefully this won’t be too disruptive further south around Tokyo, where the vast majority of events are being held (the pink balloons in the map below):

Last and certainly least, the US National Hurricane Center is monitoring a low pressure system that has been lurking over the southeast, and is now offshore from Florida. The best bet is it will drift towards Jacksonville, dumping some rain on Florida, Georgia, and the South Carolina coast and midlands. NHC gives it a 50% chance of becoming a depression. It’s not very organized, with convection displaced well away from the center, although satellite radar has picked up some scattered intermittent tropical storm force winds. An airplane is going in to investigate later today. I wouldn’t be surprised if NHC does start advisories, given how close to shore it is, just in case a surge of organization before “landfall” causes it to meet the narrow technical definitions of a tropical cyclone. Either way, this will more than likely be a non-event from a major impact standpoint. Worst case is some wind, flooding in the same places it floods every time there is a summer downpour, scattered power outages, etc. Here’s the current track models – be aware these lines are all well below hurricane force, most aren’t even tropical depression, just tracking the “center” of the low …

The damage swath map using GFS is boring, so I’m not bothering. Enjoy the rest of the weekend!

#Olympics #Typhoon, #China/#Shanghai Update (Sat 24 July 2021)

While no giant radioactive lizards have been sighted (yet), it does seem mother nature has it in for the Tokyo Olympics. Here is the current forecast damage swath:

Nepartak impact swath with Venues marked (pink balloon things). Click to embiggen.

At least this track keeps the worst away from Tokyo. There are two venues in the main risk zone based on this forecast, both football venues (soccer for you illiterate Americans πŸ˜› ). The primary risk from Nepartak (which may not reach typhoon/hurricane strength) will be a lot of rain. Landfall is currently on track for Sendai, and of course to the excitement of monster fans everywhere, just north of the thousands of corroding tanks of radioactive water stored at the site of the Fukushima accident. A lot of rain isn’t great given the condition of the site, but better than a full blown typhoon.

A bit south, another typhoon is headed for landfall tomorrow. After side swiping Okinawa and Taiwan, Typhoon In-Fa is now forecast to impact the densely populated Hangzhou Bay area, which includes the Shanghai area.

Given the funnel shape of the bay, even though a decaying tropical storm it is possible that up to three meters (10 feet) of water could be pushed up into the Shaoxing area and up the Yangtze river toward Hangzhou:

Current impact estimates are topping $6 Billion US Dollars, which is a lot for a minimal hurricane/tropical storm landfall, but given the dense population and development, shape of the bay, and previous rainfall, not surprising.

Squashed spiders and magic words

The low pressure system off the coast of Florida hasn’t changed much as of Saturday morning, although NHC now has the probability of a tropical depression forming at medium (50%). Note that this advisory has the magic words (in bold):

Satellite data indicate that the low pressure system located about 150 miles east of Daytona Beach, Florida, remains elongated and not well defined. In addition, showers and thunderstorms are currently limited near the low. However, environmental conditions are
expected to become a little more favorable for development, and a tropical depression could form during the next day or two while the low meanders offshore or near the Florida peninsula. Interests in Florida should monitor the progress of this system.

As I constantly rant, NHC is pretty good in how they phrase these advisories. If you see the words “interests in <somewhere> should <do something>” and you are <somewhere> then <do something>. If you aren’t <somewhere>, you can probably not worry about it too much and give your refresh key a break.

The track models this morning are a pretty classic “squashed spider” look:

The blue line going to Florida is the most likely … click to embiggen.

The main threat from this system will probably be rain; it doesn’t seem that any of the models are enthusiastic about it becoming more than a minimal tropical storm. So if it does come ashore, that’s flooded streets, a few limbs down, scattered power outages. If you live in Florida (or GA/SC for that matter), if you’ve not raided your hurricane snack supplies, this shouldn’t be a big deal. Otherwise, this should at worst be a time to rethink your plans in case a real storm comes along later this year.

Invest off SE US Coast

NWS has started track models on the thing off the SE US coast. To reiterate, the National Hurricane Center (NHC) only has this tagged with a 30% chance of spinning up right now, but there has been a burst of offshore convection, as seen on the current (10:20am) satellite images:

AL90 – Center of circulation is at the north edge (upper ) of the thick bubbly clouds off Florida

If you just insist on uncooked pasta, here’s the early track models:

Over time more will either lock on to a circulation or not. Best bet right now is a drift south towards the Bahamas and then inland over Florida, not becoming a tropical storm. The 8am discussion didn’t have any red flags, so nothing to worry about right now.

Still watching the West Pacific (#Taiwan, #China, #Japan), NHC’s Yellow Blob near SEUS

Typhoon In-Fa is over the small southern Ryuku Island of Miyako-jima this morning, fortunately having weakened a bit from its peak of 95 knots (borderline Category 3) to 80 knots (strong Category 1). Here is the projected damage swath:

click any graphic to embiggen.

It looks like Taiwan will be largely spared, although heavy rains continue over the north end of the island. However, the decaying storm looks to bring some additional misery to mainland China, which has suffered from a series of floods. The exact track here will matter a lot, as landfall is currently forecast to be just south of Shanghai. While current damage forecasts are for around $1 Billion USD in China, slight changes in the track or intensity could cause this number to drop by 50% or jump by a factor of five! Landfall is expected Sunday afternoon/evening – we should have a better estimate of impacts tomorrow.

There are two other West Pacific systems – Typhoon Cempaka is now a depression and is dissipating over the Gulf of Tonkin, whereas invest area WP90 is now a subtropical storm/depression. JTWC has not started advisories, but the Japan Meteorological Agency has, with projected landfall near Iwaki, in the middle of the main island of Honshu (100miles/160km northeast of Tokyo). Here’s the current (Friday AM US East Coast time) track cloud …

JTWC will probably start tracking today or tomorrow. It looks like this will more than likely be more rain than wind, but given the Olympics, needs to be carefully watched.

In the Atlantic, the National Hurricane Center has a yellow blob of doom just off the Georgia coast. A very weak low has drifted offshore, and should meander there for a few days. NHC gives it a 30% chance of spinning up in then next five days, but the latest model runs aren’t terribly enthusiastic. Anyway, here is a terrifying picture of the low just off of Savannah, showing the winds and 850mb heights (how high up the 850mb pressure level is, normally it is about 5000 feet. Lower and circular isopleths are an indication of structure and strength).

GFS model 5am ET 850mb Heights (9hr forecast)

#Olympics #Typhoon? West Pacific storms and Atlantic, um, something.

First up … as if Japan didn’t need another problem of Olympic proportions (sorry), an invest area off the coast might spin up and slam the main Island:

GFS Forecast for WP90. Click to embiggen.

Naturally, this the impact zone is near the damaged Fukushima power plant. This brings to mind the following meme …

Everybody wants to go to the Olympics …

Of course, it’s not funny, but in this business you have to laugh to keep from crying sometimes. On the somewhat positive side, Typhoon In-Fa so far hasn’t become as strong as forecast, and while it is hitting Miyako-jima and the far southern Ryuku islands with hurricane conditions, only sideswiped Okinawa, and looks to do the same to northern Taiwan, the main risk being heavy rains. By Sunday the storm should make landfall in Hangzhou province, China, as a minimal typhoon or tropical storm. Here’s the impact swath:

Nothing really to say about the yellow X and giant yellow blob on the NHC’s five day outlook. A low pressure system is expected to wander off the coast into an area that might maybe develop in to something. Not really anything to get excited about yet, although I suspect that won’t stop the usual suspects.

Threading the needle: #Okinawa, #Taiwan, #China, Atlantic Invest

Very different picture in the West Pacific this morning. Amazingly, while In-Fa (WP092021) is now forecast to the current forecast track to flirt with Saffir Simpson Category 4 status, it looks to “thread the needle” and while this isn’t great news for the southern Ryuku Islands (Miyako-jima, Ishigaki-shima), if this holds up it’s much better for Taiwan. The storm is moving away from Okinawa this morning US East coast time, and while there will be gust winds and rain, it should not be catastrophic unless something breaks that shouldn’t. Likewise, while there will be damage and disruption to Taipei and northern Taiwan, again the wind speeds should be below Typhoon (hurricane) force:

WP Storms Wed. Morning: click to embiggen.

For those who haven’t worn out their refresh key watching the US National Hurricane Center web site, you will notice a yellow blob just off the Georgia coast. No, it’s not a giant blob of pollen, it’s an area that NHC thinks has a 20% chance of becoming organized next weekend:

ZOMG! A Yellow Blob!

As usual, if NHC doesn’t have the magic words “Interests <somewhere> should <do something>”, (which it doesn’t in this case), the unless you are “somewhere” you don’t need to “do something.” An organized low may or may not form offshore by the weekend. Probably not, but if it does, we will have plenty of warning, so nothing to get excited about.