Disturbance 99L more organized; record melting in Austrian Alps

By: Dr. Jeff Masters , 2:02 PM GMT on August 01, 2012

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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

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this is the FIM model on 99L


or


anyway I expect 99L to track like this
Member Since: June 13, 2009 Posts: 2 Comments: 9557
Quoting kmanislander:


I posted this steering map earleir showing the weakness in the high to the North of 99L's current position. It appears to be responding to this by pulling up in latitude but I do not expect that to continue. A more Westerly track should resume later as it reaches the Western edge of the weakness and the flow from East to West strengthens.



OK, thanks BRO
Member Since: June 20, 2012 Posts: 0 Comments: 2130
TCFA just issued for 99L.
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Quoting TropicalAnalystwx13:
If we have recon tomorrow then the National Hurricane Center may not upgrade until then. It's organized enough to be classified right now, but they may see how it fares overnight considering it fell apart some last.


If it's a tropical cyclone, it's a tropical cyclone. No need to put off classification for 24 more hours just because of recon. If trends continue, this is getting classified today.
Member Since: July 15, 2006 Posts: 17 Comments: 10156
Quoting LargoFl:
Hurricanes can cause catastrophic damage to coastlines and several hundred miles inland. Hurricane can produce winds exceeding 155 miles per hour as well as tornadoes and mircrobursts. Additionally, hurricanes can create storm surges along the coast and cause extensive damage from heavy rainfall. Floods and flying debris from the excessive winds are often the deadly and destructive results of these weather events. Slow moving hurricanes traveling into mountainous regions tend to produce especially heavy rain. Excessive rain can trigger landslides or mud slides. Flash flooding can occur due to intense rainfall.

Between 1970 and 1999, more people lost their lives from freshwater inland flooding associated with tropical cyclones than from any other weather hazard related to such storms.


Yeah and the widest part of FL is about 160 miles...
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Quoting mobileshadow:

WTNT21 KNGU 011430
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
100 NM EITHER SIDE OF A LINE FROM 10.8N 47.0W TO 11.2N 53.0W
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 20 TO 30 KNOTS. METSAT IM-
AGERY AT 011315Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 10.8N 47.0W. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 15
KNOTS.
2. REMARKS:
CURRENT MODEL GUIDANCE IS DEPICTING INTENSIFICATION OF A TROPICAL
WAVE LOCATED ABOUT 870NM EAST OF THE SOUTHERN WINDWARD ISLANDS.
AT 011315Z, VISIBLE SATELLITE IMAGERY INDICATED AN AREA OF SCAT-
TERED MODERATE/STRONG CONVECTION THAT HAS PERSISTED OVER THE LAST
24 HOURS. WARM SEA SURFACE TEMPERATURES OF 82 TO 84 DEGREES
FAHRENHEIT IN CONJUNCTION WITH A FAVORABLE UPPER AIR ENVIRONMENT
MAY ENHANCE DEVELOPMENT OF THIS SYSTEM INTO A TROPICAL CYCLONE.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 021430Z.//
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Convection is starting to redevelop just south of the LLC.

Might be exsposed.

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Quoting stormchaser19:


Woow...The system looks like is moving north-northwest now


I posted this steering map earlier showing the weakness in the high to the North of 99L's current position. It appears to be responding to this by pulling up in latitude but I do not expect that to continue. A more Westerly track should resume later as it reaches the Western edge of the weakness and the flow from East to West strengthens.

Member Since: August 19, 2006 Posts: 0 Comments: 15671
Quoting TropicalAnalystwx13:
If we have recon tomorrow then the National Hurricane Center may not upgrade until then. It's organized enough to be classified right now, but they may overnight considering it fell apart some last night.
..you could very well be right there
Member Since: August 6, 2011 Posts: 4 Comments: 33355
Quoting AussieStorm:

I hate to tell you but it's not.


Typhoon Saola
I saw one time lapse picture when they were closer together and an outflow band of clouds clearly disrupted Damrey.It didn't last long though because of the differing tracks.First time to ever see that occur for me.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Hurricanes can cause catastrophic damage to coastlines and several hundred miles inland. Hurricane can produce winds exceeding 155 miles per hour as well as tornadoes and mircrobursts. Additionally, hurricanes can create storm surges along the coast and cause extensive damage from heavy rainfall. Floods and flying debris from the excessive winds are often the deadly and destructive results of these weather events. Slow moving hurricanes traveling into mountainous regions tend to produce especially heavy rain. Excessive rain can trigger landslides or mud slides. Flash flooding can occur due to intense rainfall.

Between 1970 and 1999, more people lost their lives from freshwater inland flooding associated with tropical cyclones than from any other weather hazard related to such storms.
Member Since: August 6, 2011 Posts: 4 Comments: 33355
If we have recon tomorrow then the National Hurricane Center may not upgrade until then. It's organized enough to be classified right now, but they may see how it fares overnight considering it fell apart some last.
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Quoting TropicalAnalystwx13:

It stays red until it appears that the United States will suffer a direct impact from a major hurricane.


LOL :)
Member Since: June 20, 2012 Posts: 0 Comments: 2130
Quoting TropicalAnalystwx13:

It stays red until it appears that the United States will suffer a direct impact from a major hurricane.

Ok, gotcha. I got the other colors right, correct? Just making sure.
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99L's surface circulation seems to be becoming better defined. I can definitely see this being classified at 5PM. Time will tell, of course.
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We will have TD or TS by 5 it a 11 or 12N now and it is 11:30
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Quoting SFLWeatherman:
11 or 12N now


Woow...The system looks like is moving north-northwest now
Member Since: June 20, 2012 Posts: 0 Comments: 2130
Quoting Bluestorm5:


So Green: Nothing is going on
Yellow: Threat of development
Red: Tropical Storm/Minor Hurricane
Blue: Major Hurricane.

Is that right?

It stays red until it appears that the United States will suffer a direct impact from a major hurricane.
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Member Since: August 6, 2011 Posts: 4 Comments: 33355
I doubt that 99L survives thru the Eastern and central carribean. Ive seen too many storms go against less hostile conditions then 99L will be facing and... not make it. I think its pretty safe to say that we wont have a CAT 4 in the Carribean out of 99L! LOL
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Quoting MississippiWx:
Could be our 5th system in a row to go straight to TS status.

Updated Vis
Based on VIsible images it appears we are very very close to Upgrade 99L looks real good , all it needs its for the center to become more defined so looks to me either a 11pm or tomorrow morning upgrade
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WEATHER RECONNAISSANCE FLIGHTS

CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.

1100 AM EDT WED 01 AUGUST 2012

SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)

VALID 02/1100Z TO 03/1100Z AUGUST 2012

TCPOD NUMBER.....12-075


1. SUSPECT AREA.....APPROACHING THE LESSER ANTILLES

FLIGHT ONE -TEAL 70-

A. 02/1800Z

B. AFXXX 01BBA INVEST

C. 02/1530Z

D. 12.4N 54.4W

E. 02/1730Z TO 02/2030Z

F. SFC TO 10,000 FT



FLIGHT TWO -TEAL 72-

A. 03/0600, 1200Z

B. AFXXX 0205A CYCLONE

C. 03/0400Z

D. 13.0N 57.5W

E. 03/0530Z TO 03/1200Z

F. SFC TO 10,000 FT

2. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 6-HRLY FIXED
Member Since: June 13, 2009 Posts: 2 Comments: 9557
Quoting Stormchaser2007:


I've been following the FIM for (I think) three years now, and with each upgrade they implement, the more confident I am that this will be a solid model one day.

Now that makes the 2 of us.
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Quoting kmanislander:


I discussed this type of scenario a couple of days ago with the system staying fairly low until 75W and then making more of a pronounced WNW motion through those very high TCHP readings in the NW Caribbean. That is a long way off but not to be discounted at this time. For now, 99L looks to be struggling a bit and there is a dry air slot on the NW side of the circulation that could spell short term trouble.

I will be looking to see if any outflow boundaries start to show up in the next 2 to 4 hours.


Keep an eye out for 99L Kman, as it's taking the southern route thru the Caribbean.
Member Since: July 14, 2008 Posts: 1 Comments: 9625
Quoting LargoFl:
..now That..seems a more likely track, lets see if this pans out



Yes, the most likely ATM. Depends on the set up along the east coast however and how strong 99L when it gets there. Could very well make a right turn if there is a formidable trough and a Hurricane Ernesto. Being so early in August I am more inclined to think the latter but, we'll see.
Member Since: August 19, 2005 Posts: 5 Comments: 4863
Quoting TropicalAnalystwx13:

I was going to change it anyways when TD #5/Ernesto was declared, but I switched a bit early.


Blue.


So Green: Nothing is going on
Yellow: Threat of development
Red: Tropical Storm/Minor Hurricane
Blue: Major Hurricane.

Is that right?
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Quoting bappit:
Houston-Galveston forecast discussion:

FOCUS IS TURNING MORE TO THE TROPICS AS A CAPE VERDE WAVE LOCATED AROUND 45W TRAVELS INTO THE LESSER ANTILLES BY DAY 3. TPC HAS GIVEN THIS WAVE A DECENT CHANCE TO ORGANIZE INTO A TC. GIVEN THAT OUR ONGOING RIDGE WILL MOST LIKELY STILL BE A DOMINANT FEATURE...THE THREAT TO OUR COAST IS MINIMAL. AS THE RIDGE WILL SLIGHTLY WEAKEN AND THE AFOREMENTIONED EASTERN US/GULF TROF (OR BOUNDARY) WILL COME INTO PLAY...THIS MAY PROVIDE A MORE N-NE STEERING MECHANISM. IF THIS WAVE DOES EVOLVE...ANOTHER PATH WOULD BE UNDER GULF RIDGING...STEERED NEAR DUE WEST TOWARDS THE YUCATAN PENINSULA/BAY THIS TIME NEXT WEEK. NWP DOES NOT DO MUCH WITH THIS WAVE...BARELY DISCERNIBLE BY EARLY IN THE WEEK. IT DOES BEAR NOTE THAT BOTH THE GFS AND ECMWF LEAN TOWARDS A MORE ACTIVE GULF (QPF- WISE). THE EURO IS THE AGGRESSOR ON DEVELOPING AN UPPER-LEVEL INVERTED TROF OVER THE TEXAS COAST BY DAY 7 OR 8. IT`S GETTING TO BE THAT TIME OF YEAR AGAIN...


That was a confusing weather statement.
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11 or 12N now
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I think thursday will be the day of best environment for 99L until he get out of the carribean,but some models are suggest a cat.1 hurricane (hwrf), looks like in some places in the carribean the patterns will be not bad at all.
Member Since: June 20, 2012 Posts: 0 Comments: 2130
Quoting MississippiWx:
Could be our 5th system in a row to go straight to TS status.

Updated Vis
I definitely see new convection firing which is a good sign for 99L and it already has 30knt winds so its possible.
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Quoting ProgressivePulse:
Some of the models are portraying a N-ward turn around the Central Caribbean today as shown in the consensus model TVCN. Could be that the Atl. Ridge is eroded on the western edge by the low on the east coast and the Twave near Hispaniola.



I discussed this type of scenario a couple of days ago with the system staying fairly low until 75W and then making more of a pronounced WNW motion through those very high TCHP readings in the NW Caribbean. That is a long way off but not to be discounted at this time. For now, 99L looks to be struggling a bit and there is a dry air slot on the NW side of the circulation that could spell short term trouble.

I will be looking to see if any outflow boundaries start to show up in the next 2 to 4 hours.
Member Since: August 19, 2006 Posts: 0 Comments: 15671
According to what I've heard over the past few weeks (and Levi just mentioned it in his tidbit), the FIM model is expected to replace the GFS model over the next few years.

Maybe we need to find one to replace the CMC and NOGAPS.
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Recon has been put up for tomorrow.

Good stuff.
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If it wasn't closed before, I'd say it is now. Seems to have tightened up quite a bit the last couple frames.
Member Since: August 19, 2005 Posts: 5 Comments: 4863
Quoting Levi32:


It has been getting stronger with it in the western Caribbean with every run.


I've been following the FIM for (I think) three years now, and with each upgrade they implement, the more confident I am that this will be a solid model one day.

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Quoting Stormchaser2007:
6z 15km FIM (EXPERIMENTAL!) has a Caribbean Cruiser




Decent Category 1 hurricane. It would not surprise me in the slightest to see it stronger given what the environment should be if it makes it there...which there is a high chance it does.

The LGEM brought it up to Category 2 intensity in 5 days earlier this morning.



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I think the LLCOC is just Sof where that new blow up of convection and a tad bit E near 10.8N 47.4W moving W-North of due West
Member Since: June 13, 2009 Posts: 2 Comments: 9557
Member Since: August 6, 2011 Posts: 4 Comments: 33355
Quoting washingtonian115:
Ernesto why do you have to be a pest?.Can't you just be like your 2000 counter part?.A tropical storm that had max intensity of 40mph and lasted only two days... and died out in the Atlantic....
You mean this little guy, he seemed like a shy little kid that came and went unnoticed.
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WEATHER RECONNAISSANCE FLIGHTS

CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.

1100 AM EDT WED 01 AUGUST 2012

SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)

VALID 02/1100Z TO 03/1100Z AUGUST 2012

TCPOD NUMBER.....12-075


1. SUSPECT AREA.....APPROACHING THE LESSER ANTILLES

FLIGHT ONE -TEAL 70-

A. 02/1800Z

B. AFXXX 01BBA INVEST

C. 02/1530Z

D. 12.4N 54.4W

E. 02/1730Z TO 02/2030Z

F. SFC TO 10,000 FT



FLIGHT TWO -TEAL 72-

A. 03/0600, 1200Z

B. AFXXX 0205A CYCLONE

C. 03/0400Z

D. 13.0N 57.5W

E. 03/0530Z TO 03/1200Z

F. SFC TO 10,000 FT

2. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 6-HRLY FIXED.
Member Since: Posts: Comments:
Could be our 5th system in a row to go straight to TS status.

Updated Vis
Member Since: July 15, 2006 Posts: 17 Comments: 10156
I've made a drinking game out of reading Dr. Master's blogs. Feel free to play along! One shot for every instance of 'extreme' or 'record.' Double shots if the blog includes the phrase 'record amount of records'
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Quoting Stormchaser2007:
6z 15km FIM (EXPERIMENTAL!) has a Caribbean Cruiser




How strong is it? 60-65kt? I can't tell...
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Quoting Stormchaser2007:
6z 15km FIM (EXPERIMENTAL!) has a Caribbean Cruiser



..now That..seems a more likely track, lets see if this pans out
Member Since: August 6, 2011 Posts: 4 Comments: 33355


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Quoting Stormchaser2007:
6z 15km FIM (EXPERIMENTAL!) has a Caribbean Cruiser





It has been getting stronger with it in the western Caribbean with every run.
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Quoting cg2916:


Looks like a Dean/Felix track.
isn't it too south to catch it?
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6z 15km FIM (EXPERIMENTAL!) has a Caribbean Cruiser



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Member Since: August 6, 2011 Posts: 4 Comments: 33355

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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.