Disturbance 99L more organized; record melting in Austrian Alps

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

Share this Blog
36
+

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

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 336 - 286

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31Blog Index

cv.wave.is.coming.back..female
Member Since: Posts: Comments:
Convection continues to build in the eastern semicircle.

Member Since: Posts: Comments:
I thought that between 0-10 n there was not enough spin to get a storm going.
Member Since: Posts: Comments:
Quoting MississippiWx:


Tis, but not from SW shear...


Does it matter why it is exposed ?. Could be due to dry air ingestion or the surface low outrunning the convection. Could even be a combination of factors. Whatever the reason an exposed center is a short term set back.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting AussieStorm:

HAHAHAHA

Is this true???
Tax on U.S. Olympic medalists. Gold: $8,986 Silver: $5,385, Bronze $3,500. US 1 of only a few countries taxes "worldwide" prize income.


Next!!!!!


All the prize money you get with a medal must be placed on your tax return and you have to pay taxes on based on your tax bracket...

Prizes:

$25k for gold
$15k for silver
$10k for bronze

So you can pay up to 35%, or if you are someone like missy franklin who doesnt accept money in the first place, you wont owe anything
Member Since: February 11, 2012 Posts: 0 Comments: 9720
Quoting LargoFl:
..the one good thing..hmm if we can call it that...is that its NOT..going up the east coast..at least so far huh


Well, it is still too early to tell. The MOHM model disagrees with most of this right now. I believe depression status will come sooner than Thursday.
Member Since: July 17, 2009 Posts: 69 Comments: 25369
Quoting Pocamocca:
The 12Z GFS has initiated.

North of 10 N and around 47.5 W
Member Since: Posts: Comments:
sorry if a little late just came in for lunch
i have to work for a living
Member Since: July 15, 2006 Posts: 169 Comments: 53296
I read your blog Gro :).I'm not sure who the guy is.
Member Since: Posts: Comments:
Goodnight all. Stay safe, stay cool, get prepared.
Member Since: Posts: Comments:
on rgb I see a spin at 11.7N 47.5W looks to be making a quick jog to the WNW W track shoud start back very very soon convection is now starting to wrap around the circulation
Member Since: Posts: Comments:
Quoting kmanislander:
Looks exposed to me



Tis, but not from SW shear...
Member Since: Posts: Comments:
Quoting scott39:
99L will be a Lesser Antilles event. Expect a moderate to strong TS at best and some rain for the Carribean Islands. If (and that is a BIG if) it survives through the hostile conditions in the Eastern and central Carribean....we may see some re-organizing in the Western Carribean/GOM.
What hostile conditions? Shear is running below average check this 5 day java loop and you'll see what I mean.

Caribbean Vertical Shear running below Climo:

Member Since: Posts: Comments:
Quoting jeffs713:


Honestly, if you're stuck in an attic, that means you probably don't have much of a hurricane kit to speak of, and are rather unprepared anyway. (part of any hurricane or disaster kit is knowing what to be prepared for).

As for the chain saw... its gas-powered (Stihl MS 211). And both my neighbor and I *always* have at least a 5-gallon can of gasoline full (each) during the hurricane season.

If you're stuck in the attic it probably means you were stupid enough not to evacuate in the first place..
Member Since: July 6, 2010 Posts: 113 Comments: 31462
116 wunderkidcayman [at 2:47pmGMT inre 12pmGMT ATCF mapping]: umm winds increased to 30kt

Changed and THANKS. The 12pmGMT ATCF was altered after I last checked. Supposedly at 2:59pmGMT (by the timestamp on the tcweb page) but it hadda have been a bit earlier.
Member Since: Posts: Comments:
See this is why I can't live in hurricane alley.To much stuff to prepare for.Especially dealing with the insurance company....
Member Since: Posts: Comments:
Quoting washingtonian115:
Gro you writing a blog anytime soon?.


No one reads it, why should I bother. By the way, who was the guy who wrote this morning that the next blow-up of convection would be in the NW quadrant??

Member Since: July 17, 2009 Posts: 69 Comments: 25369
Member Since: Posts: Comments:
Quoting Grothar:
Still no consensus on the GFS.


At least the ensembles stay in the Caribbean, if they were everywhere then it would be difficult to pick a track. We think a Caribbean track is the best track, where it goes in the Caribbean is up to 99L.
Member Since: March 16, 2012 Posts: 127 Comments: 7927
Quoting AussieStorm:

HAHAHAHA

Is this true???
Tax on U.S. Olympic medalists. Gold: $8,986 Silver: $5,385, Bronze $3,500. US 1 of only a few countries taxes "worldwide" prize income.


Next!!!!!

It wouldn't shock me, but it is likely out of context, too.
Member Since: August 3, 2008 Posts: 16 Comments: 5871
Fleet Weather Center Norfolk Virginia

Tropical Cyclone Formation Alert (TCFA) 99L
August-01-12, 11:45:02 AM | Maritime.CDO@navy.mil (FWC-N CDO)

ALERT ATCF MIL 99X XXX 120801120000
2012080112
10.8 313.0
11.2 307.0
100
10.8 313.0
011430
1208011430
1
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.//
9912072912 87N 341W 20
9912072918 87N 344W 20
9912073000 87N 347W 20
9912073006 87N 351W 20
9912073012 87N 355W 20
9912073018 87N 358W 20
9912073100 89N 366W 20
9912073106 91N 381W 20
9912073112 93N 398W 20
9912073118 94N 414W 25
9912080100 99N 432W 25
9912080106 103N 450W 25
9912080112 107N 469W 30

Member Since: July 15, 2006 Posts: 169 Comments: 53296
312. 7544
Quoting SLU:


99L may already be a TD since the center looks closed on vis imagery...


agree if the center is jumping north then the next model runs will be further north also
Member Since: Posts: Comments:
Gro you writing a blog anytime soon?.
Member Since: Posts: Comments:
Quoting ncstorm:


after Katrina, I think an Ax is required for hurricane supplies..people were stuck in their attics and unable to escape from the flooding..dont a utilty saw run off of electricity?


Honestly, if you're stuck in an attic, that means you probably don't have much of a hurricane kit to speak of, and are rather unprepared anyway. (part of any hurricane or disaster kit is knowing what to be prepared for).

As for the chain saw... its gas-powered (Stihl MS 211). And both my neighbor and I *always* have at least a 5-gallon can of gasoline full (each) during the hurricane season.

If you live in a hurricane-prone area, and there are any trees nearby, it is a good idea to either own a chainsaw, or know someone nearby that does. Can help out a LOT when a tree falls across a street, or into a house. Could potentially save a life, too, considering that opening up street access can allow emergency vehicles to get where they need to go.
Member Since: August 3, 2008 Posts: 16 Comments: 5871
..the storms are beginning in central and northern florida
Member Since: Posts: Comments:
306. SLU
Quoting SLU:
IMO 11.7N 47.5W


99L may already be a TD since the center looks closed on vis imagery...
Member Since: Posts: Comments:
Quoting kmanislander:


Notice too that the "tail" of vorticity off to the SW that has existed for several days is now almost gone. This suggests consolidation which should lead to a closed low very soon, if not already. The overall appearance is still somewhat ragged though and it seems to be fighting off less than ideal upper air conditions at the moment.
Signs point to a developing TD, but convection needs to recover the coc which 99L is trying to do.
Member Since: March 16, 2012 Posts: 127 Comments: 7927
Quoting Grothar:
Still no consensus on the GFS.

..the one good thing..hmm if we can call it that...is that its NOT..going up the east coast..at least so far huh
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting kwgirl:
Mosquito repellant and for those who refuse to evacuate, a magic marker.
definitely need that doesn't matter if a Hurricane is coming or not they are out on full force during the entire summer.
Member Since: Posts: Comments:
Looks exposed to me

Member Since: Posts: Comments:
Quoting ncstorm:


You forgot an Ax


LOL...kind of. In Isaacs Storm Louise's mother used an ax to chop holes through the floors of their home in hopes the rising water would act as an anchor.
Member Since: Posts: Comments:
99L will be a Lesser Antilles event. Expect a moderate to strong TS at best and some rain for the Carribean Islands. If (and that is a BIG if) it survives through the hostile conditions in the Eastern and central Carribean....we may see some re-organizing in the Western Carribean/GOM. IMHO
Member Since: Posts: Comments:
Quoting icmoore:


Whew is right I don't even like to think about that. The tiny cottage we moved into in Dec is just behind the Church By The Sea which fronts Gulf Blvd...but it was built in 1947 and has survived so far :) fingers crossed it stays that way.
..yep we have been very lucky so far..shields up LOL
Member Since: Posts: Comments:
297. eddye
ppl go in tropics chat so we can talk about 99 l
Member Since: Posts: Comments:
Quoting Grothar:
Still no consensus on the GFS.


That looks like a shotgun blast of a model run if I ever saw it.
Member Since: August 3, 2008 Posts: 16 Comments: 5871
Quoting jeffs713:

Axe or saw are both recommended, but not required. I have a utility saw in my house (it can handle anything up to about 5" in diameter, at which point I'd go to my neighbor who has a chainsaw). I have several 3 and 4 cell LED Maglites for flash lights - they are excellent on both battery usage and bright light, but also handy clubs.

Don't forget canned goods and non-perishable foods. Camp stoves are awesome, along with propane BBQ grills (with an extra full tank at all times).


after Katrina, I think an Ax is required for hurricane supplies..people were stuck in their attics and unable to escape from the flooding..dont a utility saw run off of electricity?
Member Since: Posts: Comments:
294. SLU
IMO 11.7N 47.5W
Member Since: Posts: Comments:
camping gear (tent, solar shower bags, tarps.....tarps and more tarps..) take all 2liter empty bottles and fill with water and freeze...milk jugs ect... this will make ice and drinking water
Member Since: Posts: Comments:
Member Since: March 16, 2012 Posts: 127 Comments: 7927
Quoting wunderkidcayman:

simmlar here I have 10.8N 47.4W


Well there is no spin there and the new 850 map takes my side as well. The center is definitely partially exposed.
Member Since: Posts: Comments:
Quoting ryang:
Hey Stormchaser, how close is the Kalvin Wave to 99L right now?


Very close.

There may be some conflict since the TUTT is shearing the system, but there still a decent chance that CCKW will enhance convection.

Member Since: Posts: Comments:
Still no consensus on the GFS.

Member Since: July 17, 2009 Posts: 69 Comments: 25369
Quoting kmanislander:
The center of the circulation is at risk of becoming exposed, probably due to the impact of higher shear values on its Northern edge as a consequence of the change in direction of travel. This image below shows what I am referring to.



Yeah, but convective blow-off doesn't support shear being much of an influence. Since any shear would be southwesterly, there should be blow-off to the north and east. Dry air is the biggest inhibitor.
Member Since: Posts: Comments:
Quoting kwgirl:
Mosquito repellant
..oh yes thats a biggie alright
Member Since: Posts: Comments:

Viewing: 336 - 286

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31Blog Index

Top of Page

About

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