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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Quoting stormchaser19:
Hurricane Cat.1

That's the smallest 85mph hurricane I've ever seen LOL
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Quoting Bluestorm5:
Typhoon Saola is a high-end Category 3 or low-end Category 4.



UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 01 AUG 2012 Time : 173000 UTC
Lat : 24:25:31 N Lon : 122:02:55 E


CI# /Pressure/ Vmax
5.7 / 929.4mb/107.2kt



Final T# Adj T# Raw T#
5.4 4.8 4.8

Typhoon center will say Category 2. 110 mph winds.
Thats how they roll.
Gotta go. Be back in a couple hours.
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Quoting CaribBoy:
The WNW/NW movement is evident : Link
Yes, I agree with you.
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Just updated.

Member Since: June 9, 2007 Posts: 4 Comments: 15776
Quoting Bluestorm5:
Typhoon Saola is a high-end Category 3 or low-end Category 4.



UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 01 AUG 2012 Time : 173000 UTC
Lat : 24:25:31 N Lon : 122:02:55 E


CI# /Pressure/ Vmax
5.7 / 929.4mb/107.2kt



Final T# Adj T# Raw T#
5.4 4.8 4.8

Probably a high end Category 2 or possibly a minimal Category 3. Definitely not a 4. UW-CIMSS likes to be aggressive.

Member Since: July 6, 2010 Posts: 113 Comments: 31409
Quoting Stormchaser2007:


WOW THAT'S A CRAZY NORTHWEST TURN Lol
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The northern track shown by the models would make things very hostile for 99L.

Has to skirt under Jamaica to become anything significant.
Member Since: June 9, 2007 Posts: 4 Comments: 15776
829. yoboi
Quoting louisianaboy444:


Well I am not in emergency management so I really do not know. I believe this will be put out to the news networks in plenty of time for coastal residents to heed warnings though.


thanks...just be prepared for tough questions if they do call....
Member Since: August 25, 2010 Posts: 7 Comments: 2328
Quoting Stormchaser2007:
Jamaica looks to be the one for a future landfall
Member Since: Posts: Comments:
Typhoon Saola is a high-end Category 3 or low-end Category 4.



UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 01 AUG 2012 Time : 173000 UTC
Lat : 24:25:31 N Lon : 122:02:55 E


CI# /Pressure/ Vmax
5.7 / 929.4mb/107.2kt



Final T# Adj T# Raw T#
5.4 4.8 4.8
Member Since: August 1, 2011 Posts: 28 Comments: 7896
The shape of the convection with 99L leaves much to be desired, but it's currently bursting nicely.

Member Since: July 15, 2006 Posts: 17 Comments: 10159
Quoting ProgressivePulse:
Models a bit more Nward today.


those BAM_ tracks wont leave much of the system.

but i dont trust those much anyway...

but i dont trust those anyway
Member Since: February 11, 2012 Posts: 0 Comments: 9719
Quoting MiamiHurricanes09:
They adjusted it for the 18z ATCF best track:

AL, 99, 2012080118, , BEST, 0, 120N, 482W, 30, 1008, LO


As far as classification, I could see it occurring at 5p.m. Convective organization seems sufficient, and lower-level inflow channels on visible imagery appear to be established sufficiently to yield a closed circulation.

I'd start looking around 3:55p.m EDT for a renumber.


Thanks, 09. Thought it was my cataracts playing tricks.
Member Since: July 17, 2009 Posts: 68 Comments: 25287
Quoting Stormchaser2007:


TVCN takes it just south of Jamaica.
Member Since: June 29, 2009 Posts: 13 Comments: 5300
Quoting ProgressivePulse:
Models a bit more Nward today.

Yeah, but most of those are statistical models. The more reliable dynamical models are a bit farther south.
Member Since: July 6, 2010 Posts: 113 Comments: 31409
99L future Ernesto if it turns out to be as the gfs is showing us or worse it could be our first shot of retirement of the year.
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Quoting Patrap:


Very cool ,I was at Camp Hansen in Okinawa Sept 82-83 and the day I got my orders to fly home ,the Russians blew that 747 KAL Flight with the US Congressman on board outta da sky with the Mig.

Thank you for your service to Americas and Semper Fi.

to add to that thanks to the British for their service to the UK and thanks to both forces for their brotherly love to each other and the work you do for both countrys

Semper Fi & Per Mare, Per Terram

USMC & Royal Marines---(British)
Member Since: June 13, 2009 Posts: 2 Comments: 10891
Quoting Chiggy:
12Z CMC at 144 hrs - Still the Northern solution moving NW!
if that solution pans out look out South Florida
Member Since: August 14, 2008 Posts: 0 Comments: 498
Member Since: June 9, 2007 Posts: 4 Comments: 15776
Models a bit more Nward today.
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Quoting TropicalAnalystwx13:
To be, or not to be, a tropical depression. That is the question.



TD yes
TS no
Member Since: February 11, 2012 Posts: 0 Comments: 9719
12Z CMC at 144 hrs - Still the Northern solution moving NW!
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wunderground Tropical Weather and Hurricane Page
Member Since: July 3, 2005 Posts: 420 Comments: 127512
Quoting GeorgiaStormz:


HWRF is coming for you, GFS not so much.
I dont think it will get Jamaica as much of a storm

I hope you're right.
Member Since: November 6, 2010 Posts: 11 Comments: 7816
To be, or not to be, a tropical depression. That is the question.

Member Since: July 6, 2010 Posts: 113 Comments: 31409
All eyes are with 99L but the thing exiting Africa rigth now is ugly.
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Quoting nigel20:
To last to affect Jamaica was Tropical storm Nicole in 2010.

For several days, Nicole and its precursor disturbance brought great amounts of rainfall to much of Jamaica; a maximum total of 37.42 inches (940 mm) was recorded in Belleisle, Westmoreland Parish from September 26 to 30.[6] Subsequent flooding, landslides, and strong winds affected dozens of communities,[27] and more than 300,000 residences lost power at the height of the storm.[28] Extensive damage was reported to properties and infrastructure, and the agricultural section suffered additional losses. Surface runoffs and spills from industrial facilities and sewage treatment plants caused localized land pollution, with scattered occurrences of coastal erosion and waste accumulation. Additionally, several areas sustained light damage to vegetation as evidenced by uprooted trees. The disaster affected an estimated 507,831 people;[29] it resulted in a total of 13 deaths, injured more than 27 people, and displaced 114 others.[30]

Tropical Storm Nicole (2010)


HWRF is coming for you, GFS not so much.
I dont think it will get Jamaica as much of a storm
Member Since: February 11, 2012 Posts: 0 Comments: 9719
Quoting MiamiHurricanes09:
They adjusted it for the 18z ATCF best track:

AL, 99, 2012080118, , BEST, 0, 120N, 482W, 30, 1008, LO


As far as classification, I could see it occurring at 5p.m. Convective organization seems sufficient, and lower-level inflow channels on visible imagery appear to be established sufficiently to yield a closed circulation.

I'd start looking around 3:55p.m EDT for a renumber.
Miami i if we get TD 5 i suspect a track towards the WNW coming though the islands and coming either close or over Jamaica , the caymans and possibly making landfall over central/western cuba then models have a slight N to NW bend ???
Member Since: August 14, 2008 Posts: 0 Comments: 498
To last storm to affect Jamaica was Tropical storm Nicole in 2010.

For several days, Nicole and its precursor disturbance brought great amounts of rainfall to much of Jamaica; a maximum total of 37.42 inches (940 mm) was recorded in Belleisle, Westmoreland Parish from September 26 to 30.[6] Subsequent flooding, landslides, and strong winds affected dozens of communities,[27] and more than 300,000 residences lost power at the height of the storm.[28] Extensive damage was reported to properties and infrastructure, and the agricultural section suffered additional losses. Surface runoffs and spills from industrial facilities and sewage treatment plants caused localized land pollution, with scattered occurrences of coastal erosion and waste accumulation. Additionally, several areas sustained light damage to vegetation as evidenced by uprooted trees. The disaster affected an estimated 507,831 people;[29] it resulted in a total of 13 deaths, injured more than 27 people, and displaced 114 others.[30]

Tropical Storm Nicole (2010)
Member Since: November 6, 2010 Posts: 11 Comments: 7816
It's a really tough call.

Member Since: June 9, 2007 Posts: 4 Comments: 15776
Hurricane Cat.1

Member Since: June 20, 2012 Posts: 0 Comments: 2150
Quoting 7544:
this will not be a td soon but will be a ts ernesto instead imo

also still watching that pr wave to see if it could inch further north and stay alive its trying tho


Doubt it, I didn't see any real winds above 30kts in the last ASCAT pass.
Member Since: July 8, 2005 Posts: 259 Comments: 23560
Quoting HurricaneDean07:
My guess is that we should see a reclass anytime now, and it will become a TS early tomorrow.
Wonder what the NHC will post for track.


Me too. But one thing's for sure, this thing will impact the Leeward Islands. Hope everyone out that way is prepared or are preparing!
Member Since: September 2, 2006 Posts: 110 Comments: 6872
Quoting Grothar:
I believe the circulation is much further North than the last position.

They adjusted it for the 18z ATCF best track:

AL, 99, 2012080118, , BEST, 0, 120N, 482W, 30, 1008, LO


As far as classification, I could see it occurring at 5p.m. Convective organization seems sufficient, and lower-level inflow channels on visible imagery appear to be established sufficiently to yield a closed circulation.

I'd start looking around 3:55p.m EDT for a renumber.
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802. 7544
this will not be a td soon but will be a ts ernesto instead imo

also still watching that pr wave to see if it could inch further north and stay alive its trying tho
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The Ala. MCS is in the GOM fully



"troughy"

Member Since: July 3, 2005 Posts: 420 Comments: 127512
12Z UKMET at 96 hrs - moving WNW!

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Quoting CybrTeddy:


It's possible. I'd much like to see a fresh ASCAT pass.


You may be right on doubting the circulation, but I would find it hard to believe that it hasn't been a closed circulation for several hours now.
Member Since: July 15, 2006 Posts: 17 Comments: 10159
If we get TD 5 expect a track to cover the central islands, Jamaica, Cayman Islands and beyond that it may cover central & western cuba
Member Since: August 14, 2008 Posts: 0 Comments: 498
Member Since: November 6, 2010 Posts: 11 Comments: 7816
Quoting DrMickey:

Caught this one flying itno NAS JAX; I live just off the glide slope, apparently...


On centerline, on Glide Slope..at least he dosent have to "Call da Ball".

Thanx for dat, made my day.

Member Since: July 3, 2005 Posts: 420 Comments: 127512
The WNW/NW movement is evident : Link
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Persistence is key.

If this fires more convection near the center, then that 2.0 classification should do the trick.

Member Since: June 9, 2007 Posts: 4 Comments: 15776
Quoting TropicalAnalystwx13:

Yeah.

AL, 99, 2012080118, , BEST, 0, 120N, 482W, 30, 1009, LO


12.0N is about right.
Member Since: July 15, 2006 Posts: 17 Comments: 10159
Maybe a gulf coast storm is what I need to prevent the storm from going to Miami on the 10th.
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Quoting Patrap:
Very Cool, they fine Aircraft..and they were just coming on-line when I was at School in EL Toro as Mag-13 was still flying F-4's in 80'.

MMS | Photography: Aircraft &emdash; U S Marine Corps Fighter Attack Squadron 312 FA 18 Hornet 205 II

Caught this one flying into NAS JAX; I live just off the glide slope, apparently...
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My guess is that we should see a reclass anytime now, and it will become a TS early tomorrow.
Wonder what the NHC will post for track.
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So far no TS is losing 4-2 with universal TD support
Member Since: February 11, 2012 Posts: 0 Comments: 9719
774.

Word is dat Guy Uptown has PTSD, but that could be jus a ruma'...
Member Since: July 3, 2005 Posts: 420 Comments: 127512
Member Since: July 3, 2005 Posts: 420 Comments: 127512
re: #754 - immense wave poised to come off Africa
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.