Disturbance 99L more organized; record melting in Austrian Alps
A tropical wave (Invest 99L) near 11°N 47°W, about 1000 miles east of the Lesser Antilles Islands, is showing increasing organization, and has the potential to develop into a tropical depression today or tomorrow as it moves westward at 15 - 20 mph. Visible satellite loops show that the disturbance now has two respectable low-level spiral bands, one to the north and one to the south, and a moderate amount of heavy thunderstorms near the center. The thunderstorm activity has not changed much in intensity this morning. A well-defined surface circulation is not evident on satellite images, but last night's 8:30 pm EDT pass from the ASCAT satellite showed a broad, elongated center with light winds had formed. Water vapor satellite loops show that 99L has a reasonably moist environment, and the latest Saharan air layer analysis shows that the dry air from the Sahara is not present in large quantities over the central tropical Atlantic. WInd shear over the disturbance has increased some since Tuesday, and is now at the moderate level, 10 - 15 knots. Ocean temperatures are 28°C, (82°F) which is about 0.5°C above average for this time of year.
Figure 1. Morning satellite image of Invest 99L.
Figure 2. Vertical instability over the tropical Atlantic in 2012 (blue line) compared to average (black line.) The instability is plotted in °C, as a difference in temperature from near the surface to the upper atmosphere. Thunderstorms grow much more readily when vertical instability is high. Instability has been lower than average, due to an unusual amount of dry, sinking air in the atmosphere, reducing the potential for tropical storm formation. Image credit: NOAA/NESDIS/CIRA.
Forecast for 99L
Wind shear is expected to remain light to moderate, 5 - 15 knots, through Friday, ocean temperatures will remain near 28°C, and mid-level moisture will be a moderate 60 - 70%, according to the 8 am EDT run of the SHIPS model. The disturbance has gained a bit of latitude and is now at 11°N, which will help it leverage the Earth's spin more to acquire its own spin. These conditions are probably sufficient for 99L to become Tropical Depression Five, with Thursday being the most likely day for this to happen. However, the reliable computer models are not very eager to develop 99L, and none show it becoming a hurricane over the next five days. This is probably because the atmosphere over the tropical Atlantic is unusually stable for this time of year (Figure 2), with large-scale areas of dry, sinking air present. Climatologically, we see very few Cape Verdes-type hurricanes forming near the Lesser Antilles Islands this early in August, and I expect 99L will struggle at times over the next few days. This is particularly likely if 99L goes north of 13°N, where a band a high wind shear of 20 - 40 knots associated with the subtropical jet stream lies. At 8 am Wednesday, NHC gave 99L a 60% chance of developing into a tropical depression by Friday morning. Residents and visitors to the Lesser Antilles Islands should anticipate heavy rains and strong winds from 99L beginning to affect the islands as early as Friday morning. The long-range fate of 99L next week is uncertain, but a track west to west-northwest through the Caribbean is the most popular solution from the models.
Figure 3. Typhoon Saola (bottom) and Typhoon Damrey (top) perform a pincer maneuver on Shanghai, China in this MODIS photo from NASA's Terra satellite taken at 02 UTC August 1, 2012. Image credit: NASA.
Two typhoons headed towards China
In the Western Pacific, typhoon season is in full swing with two typhoons headed towards China. The more dangerous of the two is Category 2 Typhoon Saola, which is predicted to skirt the northern coast of Taiwan and hit mainland China 300 miles south of Shanghai on Friday as a Category 3 typhoon. Typhoon Damrey, a Category 1 storm located just south of Japan, is expected to hit China about 150 miles north of Shanghai on Thursday at Category 1 strength.
Extreme heat in Oklahoma
The withering heat in America's heartland continued on Tuesday, with the prize for most ridiculous heat a 113° temperature recorded in Chandler, Oklahoma. A close second: Tulsa hit 112°, just 3° below the city's all-time high of 115° set on August 10, 1936. The low temperature in Tulsa was 88° Tuesday morning, tying the record for warmest low temperature in city history set just the previous day. Six locations in Oklahoma hit 112° or hotter Tuesday, and the forecast calls for highs near 112° again today over portions of Oklahoma.
Extreme dryness in the Central U.S.
A few final tallies for July precipitation are in, and several U.S. cities in the heart of the drought region set new records for driest July:
Joplin, MO: 0.00" (ties record set in 1946)
Springfield, MO: 0.32" (previous record 0.33" in 1953)
Sioux Falls, SD: 0.24" (previous record, 0.24" in 1947, normal is 3.09")
Record early snow melt in the Austrian Alps
One of the longest meteorological data records at high altitude comes from Sonnblick, Austria, on a mountaintop in the Alps with an elevation of 3106 meters (10,200 feet.) The observatory typically sees maximum snow depths of 3 - 4 meters (10 - 13 feet) during winter. According to weather records researcher Maximiliano Herrera, the snow had never completely melted at Sonnblick until the summer of 1992. Complete snow melt did not happen again until August 12, 2003, and has happened an average of once every two years since then--but always in September. Yesterday, on July 31, the snow completely melted at Sonnblick, the earliest melting since record keeping began in 1886. It's been an exceptionally hot summer in Austria, which experienced its 6th warmest June since record keeping began in 1767. Sonnblick Observatory recorded its all-time warmest temperature of 15.3°C (60°F) on June 30. Vienna hit 37.7°C (100°F) that day--the hottest temperature ever measured in June in Austria. Note that the two mountains in the Alps with long climate records, Saentis in Switzerland and Zugspitze in Germany, beat their records for earliest melting last year in 2011 (Saentis beat the previous record of 2003, and Zugspitze tied the record set in 2003.)
Figure 4. The Sonnblick Observatory in Austria on April 26, 2010. Image credit: Michael Staudinger.
Jeff Masters
Reader Comments
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agree its starting to fire up and thats where 99l could head too
How do not see this? That's a big trough my friend and you will continue to most likely see further shifts north on the model runs. infact the TVCN model bends 99L nnw into C Cuba in 5 days. Seems very reseasonable to me.
Where they post renumbers
For new folks, the XTRP "model" just shows the direction that the storm was moving when the model map was created. It's not an official model.
That's really not a very big trough, especially when you're talking about a system down in the Caribbean with a large Bermuda high nosing in between them.
I agree with this.
arrrggggg,,,,,,, really? lol....you have posted the same post, or something very similar to it, like 5 times. we get what you want. right now it is going wnw not W or WSW. Until the NHC says otherwise it is going WNW
That's what I've been thinking all day...a more north shift in a couple days.
Book it.
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edited for clarity.
...and TVCN is the model consensus - it's not its own model either, I believe. The "consensus" being the average of the other Dynamic models.
TVCN is NOT a model, rather it's an Average of at least 2 of GHMI, EGRI, NGPI, HWFI, GFSI, GFNI, EMXI. YOu can find more info here:
http://www.nhc.noaa.gov/modelsummary.shtml
Still an hour before the advisory. Hope 99L doesn't find its groove tonight because the islands will have very little notice if the NHC is really going to wait until their precious plane gets in there tomorrow.
Or they wait for recon.
Weakness across the eastern gulf. TVCN and UKMET seem like a good bet to me. By the way that is a pretty decent trough on coming down the eastern US.
not what I want its whats goin to happen I didn't say anything about WSW so then what in the world did WSW do to you for you to bring it up
I am just making sure that peole know that this WNW movement is not going to stick arourd for a long time so yes WNW FOR NOW
TVCN is a model that the NHC uses.
I disagree, we can have a double standard. It's important to get warnings out in time for people to react when landfall is less than 48 hours, 99L is days away from any land, no reason to rush classification until you are 100% sure.
Where is there a weakness?? I see the nose of a strong 500mb ridge over North FL extending into the Northern Gulf. It doesn't matter because this is way out in time, but as of now there is no weakness....thus the GFS and the Euro not curving it into the Eastern Gulf.
T.D yes, but needs to organize more
The results of the 1900 M.O.D. (model of doom) run are in, and it is not good folks! It quickly strengthens 99L into a healthy TS Ernesto tomorrow. MOD tracks "Ernesto" west to WNW, bringing a Cat 1 hurricane into south central Lesser Antilles.
Ernesto possibly weakens into a moderate tropical storm while tracking west to WNW across the central Caribbean, before the show really starts just west of Jamaica. Ernesto bombs out into a major hurricane, (Cat 3), just north of the Caymans as it begins turning NW towards the Yucatan Channel, around the end of the high ridge. At the end of the run MOD has Ernesto as a strong Cat 4 in the central GOM.
Doom where will it go?
Doom indicates a possible weakness from a trough over the Mississippi valley.
T.D yes, but needs to organize more fot T.S
The NHC will more than likely wait until they get recon in it and mysteriously find that it's already a tropical storm.
The cycle repeats.
I'll bet you a taco that it'll still be WNW bound when classification to a TD is made. ;-)
Yeah, like warning to people in the islands which are not "days" away from landfall...
Its a consensus of models.
Not an actual model.
here is the definition for TS and hurricane watches/warnings
Tropical Storm Warning
A Tropical Storm warning means tropical storm conditions are expected in the next 24 hours.
Tropical Storm Watch
A Tropical Storm watch means tropical storm conditions are possible in the next 24 hours.
Hurricane Watch
A Hurricane Watch means hurricane conditions are possible in the next 24 hours.
Hurricane Warning
A Hurricane Warning means hurricane conditions are expected in the next 24 hours.
Hurricane Local Statement
This statement is issued when it is necessary to inform the public of hurricane or tropical storm watches and warnings. These statements contain detailed information of when and what adverse conditions to expect as a result of the tropical system affecting the statement area.
Do you take meteorology classes if not then what you see on that model is a break between the TX Death Ridge and the Bermuda High off to the east. A track up the eastern Gulf toward the C or E Gulf seems really good to me. UKMET is on this solution as well.
I see that in 8 days. I don't see a significant enough trough to start pulling whatever 99L is north in 2-3 days. There is a LOT of real estate between where 99L will be in 2-3 days, and any trough near the east coast. That is my beef with the CMC's run - it starts turning around day 2 or 3, which I think is too early.
That said, we're still talking 5+ days down the road, a lot can happen between now and then.
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