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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Chances of landfall at any intensity
according to FSU

invest 99L.
Cuba (13%↑↑) in 7.9 days
Louisiana (11%) in 12 days
Bermuda or w/i 1 deg (11%) in 8.9 days


big blob of convection firing up near the center
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Quoting Jrrtrollkien:
"Cherry Point was my last duty station, and I sure dont miss Havelock County at all."

Baking cakes and shortnin' bread!




Havelock in my opinion is much better than MCAS Beaufort SC
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Quoting Stormchaser2007:


That new burst should help.
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Quoting GeorgiaStormz:


why?

7 of 10 99Ls will be a TD by tonight....
by tomorrow the probability is probably higher....


70% chance in the next 48 hours not 12.
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Quoting AllStar17:


When they use those words they often do 90% or higher.


they aren't certain but it's probable, hence the 70%
Member Since: February 11, 2012 Posts: 0 Comments: 9731
Quoting Stormchaser2007:


Looks like a TD to me.
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99L seems to be making strides, it's still connected to the ITCZ though is it not?
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SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MELBOURNE FL
139 PM EDT WED AUG 1 2012

FLZ045-046-053-011845-
ORANGE-OSCEOLA-SEMINOLE-
139 PM EDT WED AUG 1 2012

...A SIGNIFICANT WEATHER ADVISORY IS IN EFFECT FOR STRONG WIND GUSTS
BETWEEN 45 AND 55 MPH AND SMALL HAIL OVER CENTRAL ORANGE COUNTY...
NORTHWESTERN OSCEOLA COUNTY...SOUTHERN SEMINOLE COUNTY...

* UNTIL 245 PM EDT.

AT 137 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STORM CAPABLE OF PRODUCING STRONG WINDS AND SMALL HAIL OVER PLEASURE
ISLAND...MOVING NORTHEAST AT 25 MPH.

LOCATIONS IN THE PATH OF THE STORM WHICH MAY EXPERIENCE STRONG WINDS
AND SMALL HAIL INCLUDE INTERSTATE 4...BELLE ISLE...STATE ROUTE
417...CAMPBELL...PINE CASTLE...US 192...AND SEA WORLD.

THE PRIMARY THREAT WILL BE CLOUD TO GROUND LIGHTNING STRIKES AND
GUSTY WINDS OF 45 TO 55 MPH...WHICH CAN CAUSE UNSECURED OBJECTS TO
BLOW AROUND...SNAP TREE LIMBS OR CAUSE POWER OUTAGES. HEAVY RAINFALL
WILL TEMPORARILY REDUCE VISIBILITY. SEEK SHELTER INDOORS UNTIL THE
STORM PASSES.

LAT...LON 2868 8116 2828 8103 2821 8149 2847 8161
TIME...MOT...LOC 1738Z 241DEG 21KT 2834 8147

$$


MOSES
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Quoting yoboi:


i am not belittling anyone i said i have been thru alot of storms and katrina was the worse....and watching tv about an event is not the same as being there, that would be like me watching tv about the war in iraq being there would be differ...

I wasnt talking about you belitting anyone..
Member Since: August 19, 2006 Posts: 13 Comments: 15683
Say what you will about Levi, he is too smart a forecaster to predict what something is head this far out when it hasn't even formed yet. Unlike some others on here.
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Quoting GeorgiaStormz:


why?

7 of 10 99Ls will be a TD by tonight....
by tomorrow the probability is probably higher....


When they use those words they often do 90% or higher.
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674. wxmod
Russia Fires, right, and the Great Arctic Slush Cap, left. (Tour boats are coming. Bring the strawberry sauce.) MODIS polar view.

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Member Since: June 9, 2007 Posts: 4 Comments: 15921
this is the 180 hour to the 12z GFS





Member Since: August 19, 2006 Posts: 13 Comments: 15683
Quoting AllStar17:
Strange they'd couple 70% with "could become a tropical depression later today or tonight".


why?

7 of 10 99Ls will be a TD by tonight....
by tomorrow the probability is probably higher....
Member Since: February 11, 2012 Posts: 0 Comments: 9731
99L gaining latitude at a good pace now...
Near 13N, and should continue a WNW motion now.
It appears it gained latitude a little too quickly though, and has ran into an increased amount of wind shear, and almost caused it to expose its better defined circulation. New blow up convection over the center should keep it going, for now. It needs to organize more though, it has become assymetric with this WSWerly shear. I say it will be called Ernesto at 11pm. It is much better defined, and should be getting better as the shear lessens further west.
I give 99L a 99% chance of forming into Ernesto in the next 36 hours.
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Quoting AllStar17:
Strange they'd couple 70% with "could become a tropical depression later today or tonight".


The TUTT is really pressing on 99L.Convection looks very poor on IR.

If it doesn't generate a more organized pattern, it should stay in the 70-80% for a while.
Member Since: June 9, 2007 Posts: 4 Comments: 15921
.....................any thoughts on the low Behind 99L?
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Quoting WaterWitch11:


much love to all


We send it to you and your's as well.

: )
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666. yoboi
Quoting ncstorm:


No one was saying "which storm was better" but when you belittle someone's else experience and claim they dont know what they are talking bout especially if they were in the same storm as you were then thats where the problem comes in...People were crying at the images on TV and sent support through donations, their own personal time, put up their houses for people needing shelter..etc..in all..katrina wasnt just a NO storm..it was an America storm because the nation's people pulled together to help those affected..

My family was in Mississippi so yes Katrina has a personal emotional toll for me


i am not belittling anyone i said i have been thru alot of storms and katrina was the worse....and watching tv about an event is not the same as being there, that would be like me watching tv about the war in iraq being there would be differ...
Member Since: August 25, 2010 Posts: 7 Comments: 2344
Strange they'd couple 70% with "could become a tropical depression later today or tonight".
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Quoting MississippiWx:


70% with that wording? Must be waiting on convection to respond a little better.
And it seems to be doing just that.

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Member Since: August 2, 2006 Posts: 46 Comments: 11669
ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT WED AUG 1 2012

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

1. AN AREA OF LOW PRESSURE LOCATED ABOUT 850 MILES EAST OF THE WINDWARD
ISLANDS HAS BECOME BETTER DEFINED. ENVIRONMENTAL CONDITIONS ARE
CONDUCIVE FOR TROPICAL CYCLONE FORMATION...AND THE LOW COULD BECOME
A TROPICAL DEPRESSION LATER TODAY OR TONIGHT. THIS SYSTEM HAS A
HIGH CHANCE...70 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD AT NEAR 20 MPH.
INTERESTS IN THE WINDWARD ISLANDS SHOULD MONITOR THE PROGRESS OF
THIS SYSTEM.
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Quoting Patrap:
Dats easy WW11...a das Blue Moon I believe.

Nola Roux says Hello as well.

: )


much love to all
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Quoting MississippiWx:


Yeah, you can keep going with that Levi spill, but we all have minds of our own. Btw the NHC went with everyone else too. The only reason the GFS ended up being correct is because southwest shear never let up, causing convection to be heavily weighted to the northeast. And no, this is not a Debby setup.


With a trough in the east you can bet this will go north toward the Central or Eastern Gulf Coast.
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....................................stormtracker2 k...you online?..some strong storms coming towards you
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@ST2K...really?

Cat 3 or 4?


Take a break...enjoy a Fresca.
Member Since: June 9, 2007 Posts: 4 Comments: 15921
Quoting TropicalAnalystwx13:

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT WED AUG 1 2012

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

AN AREA OF LOW PRESSURE LOCATED ABOUT 850 MILES EAST OF THE WINDWARD
ISLANDS HAS BECOME BETTER DEFINED. ENVIRONMENTAL CONDITIONS ARE
CONDUCIVE FOR TROPICAL CYCLONE FORMATION...AND THE LOW COULD BECOME
A TROPICAL DEPRESSION LATER TODAY OR TONIGHT. THIS SYSTEM HAS A
HIGH CHANCE...70 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD AT NEAR 20 MPH.
INTERESTS IN THE WINDWARD ISLANDS SHOULD MONITOR THE PROGRESS OF
THIS SYSTEM.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER PASCH


70% with that wording? Must be waiting on convection to respond a little better.
Member Since: July 15, 2006 Posts: 17 Comments: 10284
605. TXCWC 5:22 PM GMT on August 01, 2012 +3
Quoting StormTracker2K:
Debby part 2? Very possible FL could get hit by it's 3rd Tropical system in just 9 weeks.



Way too soon to say that with any confidence - but definitely a good shift right on the track for GFS on the 12Z. More shifts either to the right or left sure to come in the coming days.


Does anyone have any information to say whether Atlantic hurricanes are more dangerous to FL if they hook from the west from the Caribbean or straightline in from the Bahamas like Andrew in 92? Wilma was bad but it seemed to me that Frances, Jeane, and Andrew caused me more headaches. If that is the case, perhaps with the models having it mostly entering the Caribbean would be a distinct advantage for me on the east coast of Florida. Our worst storm ever was from the east in 28. I would not care to want that scenario again!
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New burst of convection.

Member Since: July 6, 2010 Posts: 113 Comments: 32278
653. yoboi
Quoting MiamiSurvivor:


I survived Andrew, 1992. Don't worry, I understand, and also know that the storms were the same, and very different.



look at the world trade center bombings really only affected 2 blocks in ny and there resources were tapped, with katrina in LA hundreds of square miles flooded even with federal resources took weeks to get everyone to safety....that's the only point i am making.....the only place that could top this imo would be nyc under water from storm...
Member Since: August 25, 2010 Posts: 7 Comments: 2344
20mph is cruzin, lil too fast maybe.
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AN AREA OF LOW PRESSURE LOCATED ABOUT 850 MILES EAST OF THE WINDWARD
ISLANDS HAS BECOME BETTER DEFINED. ENVIRONMENTAL CONDITIONS ARE
CONDUCIVE FOR TROPICAL CYCLONE FORMATION...AND THE LOW COULD BECOME
A TROPICAL DEPRESSION LATER TODAY OR TONIGHT. THIS SYSTEM HAS A
HIGH CHANCE...70 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD AT NEAR 20 MPH.
INTERESTS IN THE WINDWARD ISLANDS SHOULD MONITOR THE PROGRESS OF
THIS SYSTEM.
Member Since: June 13, 2009 Posts: 2 Comments: 12157
650. SLU
RED ALERT!!
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70!!!!!!!!!!!
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70% for 99L
Member Since: June 13, 2009 Posts: 2 Comments: 12157
Quoting jrweatherman:


Poof....



this makes no sense....
ignore him for what?
Member Since: February 11, 2012 Posts: 0 Comments: 9731
Dats easy WW11...a das Blue Moon I believe.

Nola Roux says Hello as well.

: )
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000
ABNT20 KNHC 011734
TWOAT

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT WED AUG 1 2012

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

AN AREA OF LOW PRESSURE LOCATED ABOUT 850 MILES EAST OF THE WINDWARD
ISLANDS HAS BECOME BETTER DEFINED. ENVIRONMENTAL CONDITIONS ARE
CONDUCIVE FOR TROPICAL CYCLONE FORMATION...AND THE LOW COULD BECOME
A TROPICAL DEPRESSION LATER TODAY OR TONIGHT. THIS SYSTEM HAS A
HIGH CHANCE...70 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD AT NEAR 20 MPH.
INTERESTS IN THE WINDWARD ISLANDS SHOULD MONITOR THE PROGRESS OF
THIS SYSTEM.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER PASCH

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Quoting Stormchaser2007:
I'd go with 70%

Looks like it's getting nailed by shear now.


TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT WED AUG 1 2012

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

AN AREA OF LOW PRESSURE LOCATED ABOUT 850 MILES EAST OF THE WINDWARD
ISLANDS HAS BECOME BETTER DEFINED. ENVIRONMENTAL CONDITIONS ARE
CONDUCIVE FOR TROPICAL CYCLONE FORMATION...AND THE LOW COULD BECOME
A TROPICAL DEPRESSION LATER TODAY OR TONIGHT. THIS SYSTEM HAS A
HIGH CHANCE...70 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD AT NEAR 20 MPH.
INTERESTS IN THE WINDWARD ISLANDS SHOULD MONITOR THE PROGRESS OF
THIS SYSTEM.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER PASCH
Member Since: July 6, 2010 Posts: 113 Comments: 32278
Quoting StormTracker2K:


Probably a cat 3 or 4 right here on the GFS.


Can't be. I say strong TS or weak Cat 1 hurricane at best. The pressure is 990mb. It'd be almost impossible to get a Cat 3 or 4 with a pressure of 990.
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642. SLU
No doubt 99L is a TD now. I expect at least 80% and some strong language from the NHC.
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635.

Keep it on course for yer Haus, your doing a fine job.

: )

Remember to remain modest when yer,er, forecast pans out too.
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OH,Oh,oh,uhhh :( 99L is getting dangerous
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Quoting Patrap:


O yeah, time will do dat.

I used to Drink at Tony's outside the Gate a spell.

..bac in 84'.


you were drinking back in 84? you must be old. :) what do you call a moon that occurs twice in 1 month? correction: full moon
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I'd go with 70%

Looks like it's getting nailed by shear now.

Member Since: June 9, 2007 Posts: 4 Comments: 15921
Ol MrPerfect arrives on time.

Man nothing like having space in a small BHG rent free.

LOL

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Quoting yoboi:


i have been thru quite a few storms, and katrina was by far the worse, if you werent there in person ya truly don't understand, i am not saying other storms don't have emotional tolls but the magnitude was on a large scale.


I survived Andrew, 1992. Don't worry, I understand, and also know that the storms were the same, and very different.
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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.

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