90L in the Gulf disorganized; Leslie and Michael weaken

By: Dr. Jeff Masters , 4:27 PM GMT on September 07, 2012

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A partial remnant of Hurricane Isaac off the coast of Louisiana, Invest 90L, was almost torn apart last night by wind shear, but is making a bit of a comeback today. Visible satellite loops and surface observations from buoys and oil rigs in the Gulf show that 90L has an sloppy, elongated surface circulation. The area covered by heavy thunderstorms is relatively modest, and has been pushed to the south side of the circulation center by strong northerly winds that are creating a high 20 knots of wind shear. There is a large amount of dry air that surrounds 90L on all sides that is interfering with development. A hurricane hunter aircraft scheduled to investigate 90L today was cancelled, and has been rescheduled for Saturday afternoon.


Figure 1. Visible satellite image of Invest 90L taken at 11:58 am EDT Friday September 7, 2012.

Forecast for 90L
Wind shear over 90L is predicted to stay in the moderate to high range, 15 - 20 knots, through Saturday morning, then drop to the low range Saturday afternoon through Sunday. Ocean temperatures in the Gulf are 28.5° - 29°C, which is plenty warm enough to support formation of a tropical storm. 90L is essentially stationary this morning, but should begin a slow motion to the east-northeast tonight, in response to the steering flow from a trough of low pressure and its associated surface cold front approaching the Gulf Coast from the northwest. This trough should be capable of pulling 90L to a landfall along the Florida Panhandle or west coast of Florida by Sunday morning. In their 8 am Tropical Weather Outlook, NHC gave 90L a 20% chance of developing into a tropical depression by Sunday morning. I put these odds higher, at 30%.

Leslie weakens to a tropical storm
Tropical Storm Leslie continues to remain nearly stationary to the south of the island of Bermuda, and a NOAA hurricane hunter aircraft found this morning that Leslie had weakened below hurricane strength, to a 70 mph tropical storm. An ocean probe launched by the aircraft found that the ocean temperatures at one location in Leslie were 24.5°C, a full 5°C (8°F) drop from when the storm first reached the area two days ago. Moderate wind shear of 10 - 20 knots due to strong upper-level winds out of the west continue to drive dry air to Leslie's west into the core of the storm. The combined effect of shear and cool waters have eroded away Leslie's core, and the storm has no eyewall, as seen on satellite loops. A NOAA hurricane hunter aircraft will be in the storm tonight, and an uncrewed NASA Global Hawk aircraft finished an HS3 Hurricane Research Mission into Leslie this morning.


Figure 2. Hurricane Leslie as seen by NASA's Aqua satellite at 10:45 am EDT Thursday, September 6, 2012. At the time, Leslie was a Category 1 hurricane with 75 mph winds. Image credit: NASA.

Forecast for Leslie
A strong trough of low pressure approaching the U.S. East Coast should make Leslie start moving to the north at 5 mph by Saturday morning. The models have stayed with their more eastwards solution to Leslie's track, which keeps the threat of Bermuda receiving hurricane-force winds relatively low, since the island is expected to be on the weak (left) side of the storm. If the official NHC forecast verifies, tropical storm-force winds will just graze Bermuda Sunday morning through Sunday evening. According to the latest SHIPS model forecast, the shear is expected to fall to the low category, 5 - 10 knots, by Friday night. Leslie is over warm ocean waters of 29 - 30°C, and once the storm moves away from the large pool of cool waters it has stirred up, the reduction in shear and warm waters should allow the storm to intensify to at least a Category 1 hurricane by Sunday. The latest 11 am EDT NHC wind probability forecast calls for a 30% chance that Leslie will be a Category 2 or stronger hurricane Sunday morning at 8 am EDT, when the storm will be beginning its closest pass to Bermuda. Leslie is a huge storm, and tropical storm-force winds are expected to extend outward from its center 200 - 220 miles by Sunday.

Most of the models indicate Leslie is likely to make landfall in Newfoundland, Canada on Tuesday night or Wednesday morning. However, the models have been trending more to the east with Leslie's track in recent runs, and given the uncertainty in 4-day hurricane forecasts, the storm could very well miss the island, passing to the northeast. Large swells from Leslie are pounding the entire Eastern Seaboard, and are creating beach erosion and dangerous rip currents.


Figure 3. Hurricane Michael as seen by NASA's Aqua satellite at 12:20 pm EDT Thursday September 6, 2012. At the time, Michael was a Category 3 hurricane with 115 mph winds. Image credit: NASA.

Hurricane Michael weakens to Category 2
The only major hurricane of the 2012 Atlantic hurricane season, Hurricane Michael, has weakened, and is now a Category 2 storm with 105 mph winds. Satellite loops show that Michael is still an impressive storm with a well-developed eye, but the storm is not as symmetric, and the eye no longer as distinct as was the case yesterday. Michael is far out over the open Atlantic, and none of the models show that Michael will threaten any land areas during the coming seven days.

Elsewhere in the Atlantic
Most of the reliable computer models are predicting that a new tropical wave moving off the coast of Africa today will develop into a tropical depression by the middle of next week. This wave is predicted to exit Africa too far north to threaten the Lesser Antilles Islands.

Jeff Masters

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taste of fall
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650. Skyepony (Mod)
Quoting wxmod:


I know keeper. It ain't lookin too great. It appears, actually, to be looking worse than anyone predicted. And now two tropical systems are headin for Greenland.


What I predicted came to pass two days ago. So yeah, even worse than my end of winter doom scenario.

The three year scenario has been being tossed around alot the last week or so. I'll say sometime in the next 5 we have an ice free moment. It could happen sooner.
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Quoting spathy:


Thanks. That response means a lot to me.

Pie in the sky means nothing if we cant reach it.
I want a cleaner planet.
I dont want the powers that be to make a fortune and nothing be accomplished.
And in the end we dont have the revenue resources to deal with the consequences.
Please WU friends think about that scenario.


I do think about that. Every time I have to pay for the gas at the pumps.
Member Since: August 24, 2010 Posts: 0 Comments: 4745
Quoting nigel20:
Have a good night all...I'm off to bed.


Good night, Nigel.
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Have a good night all...I'm off to bed.
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643. Skyepony (Mod)
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Member Since: July 17, 2009 Posts: 71 Comments: 26472
Quoting nigel20:

Hey Tropics! That's a very nice tropical wave.

Not as nice as the third one... that's a TX storm.
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639. wxmod
Quoting KEEPEROFTHEGATE:


all the ice will come back that has disappeared this summer
and next season it will melt just as fast
if not faster than the year before
as now we have a larger area of first year slop ice
as opposed to multi-year hard ice


I know keeper. It ain't lookin too great. It appears, actually, to be looking worse than anyone predicted. And now two tropical systems are headin for Greenland.
Member Since: October 4, 2011 Posts: 0 Comments: 1764
Looks worse than Leslie

Member Since: July 17, 2009 Posts: 71 Comments: 26472
WOCN11 CWTO 080328
Special weather statement
Updated by Environment Canada
At 11:28 PM EDT Friday 7 September 2012.
------------------------------------------------- --------------------
Special weather statement for:
=new= Prescott and Russell
=new= Cornwall - Morrisburg
City of Toronto
Windsor - Essex - Chatham-Kent
Sarnia - Lambton
Elgin
London - Middlesex
Simcoe - Delhi - Norfolk
Oxford - Brant
Niagara
City of Hamilton
Halton - Peel
York - Durham
Huron - Perth
Waterloo - Wellington
Dufferin - Innisfil
Grey - Bruce
Barrie - Orillia - Midland
Belleville - Quinte - Northumberland
Kingston - Prince Edward
Peterborough - Kawartha Lakes
Stirling - Tweed - South Frontenac
Bancroft - Bon Echo Park
Brockville - Leeds and Grenville
City of Ottawa
Gatineau
Smiths Falls - Lanark - Sharbot Lake
Parry Sound - Muskoka
Haliburton
Renfrew - Pembroke - Barry's Bay
Algonquin
Burk's Falls - Bayfield Inlet.

Significant rainfall on tap tonight into Saturday.


------------------------------------------------- --------------------
==discussion==

A low pressure system developing over Western Ohio will deepen as
It tracks into Southern Ontario overnight then to Quebec on
Saturday.

This disturbance is quite laden with moisture and is expected
To bring a general 30 to 50 mm rainfall across much of the district
by Saturday evening. A few local rainfall amounts may exceed 50 mm in
areas that receive a thunderstorm or two.

In the wake of this disturbance later Saturday and into Sunday,
considerably cooler air ushered in by brisk northwesterly winds will
bring a taste of fall to Southern Ontario.

Environment Canada is monitoring this situation closely.

The public is advised to monitor future forecasts and warnings as
warnings may be required or extended.

END/KUHN/OSPC


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This looks like some event shaping up

Member Since: July 17, 2009 Posts: 71 Comments: 26472
Member Since: July 17, 2009 Posts: 71 Comments: 26472
Quoting spathy:


You know I heard a media clip on the radio while driving home.
But the report I heard was they crashed into an electrical pole and were electrocuted.

Your report seems more accurate and a more responsible report.

I dont believe the media.
Responsible reporting ,sadly is a thing of the past.

Thank you Jed for shedding light on what is obviously a more involved report.


Yeah they had a more in depth story on it here on the local news. What you heard was probably rumors being developed into a story, definitely not responsible journalism.

I think the problem is that many grow up thinking power line poles are "telephone poles". Well it's true that the lower insulted cables usually are telephone lines. But the main wires that are separated between spaces are 3 phase high voltage power lines and they are not insulated. Even the "lower" voltage power lines carry hundreds of times the amount of energy as your home wires do. Contacting them will often cause death. If you're "lucky" enough and the electric current bypasses your major organs and you survive, you'll still receive terrible burns both internal and external, and sometimes flesh is completely destroyed, and that's the lower end of high voltage lines, the ones that run through neighborhoods.
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Quoting wxmod:
Record year. Let's hope the ice comes back. I wish the oil and coal people would be a lot more helpful.



all the ice will come back that has disappeared this summer
and next season it will melt just as fast
if not faster than the year before
as now we have a larger area of first year slop ice
as opposed to multi-year hard ice
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Quoting nigel20:

Hey Tropics! That's a very nice tropiical wave.


Hi nigel. It has been very warm and dry here as Leslie continues to cause a light wind pattern combined with subsidence.
Member Since: April 29, 2009 Posts: 75 Comments: 14315
Has I said. 90L rip
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Quoting Tropicsweatherpr:
Saved image.


Hey Tropics! That's a very nice tropical wave.
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Quoting bappit:

Academic publishing is a racket.

Wikipedia is great for this blog. I can always check out any Wiki articles to see how well they are sourced.

I wish people would cite their sources on here more often. I generally don't believe anything anyone says on here just because they said it. I learn a lot from the blog, but the face value of everything is just opinion. Citing sources is a big plus. Not everyone does that unfortunately.

The NWS field office web sites are great, too. I'm surprised at the number of people posting questions on here that are readily answered by the local NWS office website.
Time to start the rinse cycle.
Good points, especially about providing sources and the publishing racket. The local NWS offices are great sources of information, usually including publications by local meteorologists.

When the web was younger many authors of scientific papers put their own papers up on the web and allowed free distribution. Then appeared sites such as Citeseer, which allowed you to search cross-reference, forward reference and backward reference. Citeseer is still around, but it seems the open science movement on the web peaked in the late 1990's, then the publishers began to crack down and enforce their copyrights.

With the internet, there is no need for these publisher "middlemen" anymore, the papers should go straight out to the scientific peers and the public as well. There is no additional cost for all the extra copies, but the publishing houses are very powerful and have our politicians either bribed or blackmailed. Copyright law becomes ever stricter, starting with the Sonny Bono Act, aka Mickey Mouse Law, which has since been extended even further. The U.S. Constitution, Article I, Section 8, Clause 8, states,
The Congress shall have Power ... To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries.
The Sonny Bono Act perverts this clause of the Constitution to use copyright to promote the profits of large corporations, while actually inhibiting the progress of the sciences and the arts. Corrupt judges have upheld this perversion.
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Quoting forecaster1:
I saw signiture pattern In Leslie I have been looking at for a decade to forecast storm energy and to figure out early on when you will get large Cat2 or higher storm. Leslie has produced this signiture and I will say now she will definately become a Cat 2 Storm.. Maybe......LOL
hmm! Leslie eye visible....
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Saved image.

Member Since: April 29, 2009 Posts: 75 Comments: 14315
Quoting Jedkins01:
2 men were electrocuted in Ft. Myers FL tonight when they were using a cherry picker to do some work on a building and the vehicle came in contact with high voltage power lines... What a brutal death, even more brutal for anyone who saw it...

That's very sad
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2 men were electrocuted in Ft. Myers FL tonight when they were using a cherry picker to do some work on a building and the vehicle came in contact with high voltage power lines... What a brutal death, even more brutal for anyone who saw it...

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Well I see an eye:) Leslie is one strange storm, the eye is due to dry air getting into Leslie's center.
Member Since: March 16, 2012 Posts: 127 Comments: 7948

Too far north?


dissipated.

am done for the day.
goodnight.
anyway, happy for nigel.
wow, jamaica beat usa!
and on the heels of the great olympic victories...
well done!
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TROPICAL STORM LESLIE DISCUSSION NUMBER 35
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122012
1100 PM AST FRI SEP 07 2012

SATELLITE IMAGERY AND REPORTS FROM NOAA P-3 AND G-IV HURRICANE HUNTER AIRCRAFT SHOW CHANGES IN THE STRUCTURE OF LESLIE THIS EVENING. THE STORM CURRENTLY LACKS AN INNER CORE...AS THE RADIUS OF MAXIMUM WINDS IS NOW ON THE ORDER OF 75 N MI. IN ADDITION...INFRARED AND MICROWAVE SATELLITE IMAGERY SHOW WELL-DEFINED CURVED CONVECTIVE BANDS OVER THE NORTHERN SEMICIRCLE AT A LARGE DISTANCE FROM THE CENTER. DROPSONDE DATA AND SFMR SURFACE WIND ESTIMATES SUPPORT AN INITIAL INTENSITY OF 55 KT...WHICH IS IN GOOD AGREEMENT WITH THE SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB. THE CENTRAL PRESSURE OF 983 MB IS BASED ON A COMBINATION OF AIRCRAFT AND NOAA BUOY DATA.

THE INITIAL MOTION IS 350/3. LESLIE IS STILL EMBEDDED IN AN AREA OF WEAK STEERING CURRENTS IN THE MIDDLE OF THE SUBTROPICAL RIDGE. THE GLOBAL MODELS FORECAST THE RIDGE WEST OF LESLIE TO BREAK DOWN AS A LARGE DEEP-LAYER TROUGH AND ASSOCIATED SURFACE COLD FRONT MOVE ACROSS THE EASTERN UNITED STATES INTO THE WESTERN ATLANTIC. THE TRACK GUIDANCE IS IN GOOD AGREEMENT THAT DURING THE NEXT 48-72 HR LESLIE SHOULD GRADUALLY ACCELERATE NORTHWARD TO NORTH-NORTHEASTWARD... WITH THE CENTER PASSING EAST OF BERMUDA BETWEEN 36-48 HR. AFTER THAT...THE GUIDANCE IS IN GOOD AGREEMENT THAT LESLIE SHOULD CONTINUE NORTH-NORTHEASTWARD...BUT THERE IS SOME SPREAD IN THE FORWARD SPEED. THE ECMWF AND GFS MODELS SHOW LESLIE SLOWING AS IT GETS CAUGHT UP IN AN UPPER-LEVEL LOW NEAR NEWFOUNDLAND...WHILE THE CANADIAN AND UKMET MODELS SHOW A FASTER MOTION. THE LATTER PART OF THE NEW FORECAST TRACK COMPROMISES BETWEEN THESE EXTREMES AND IS NEAR THE CONSENSUS MODELS. IT IS SIMILAR TO THE PREVIOUS FORECAST THROUGH 72 HR AND A LITTLE LEFT OF THE PREVIOUS FORECAST AFTER THAT.

THE INTENSITY FORECAST REMAINS COMPLICATED. ON THE PLUS SIDE...LESLIE SHOULD BE MOVING AWAY FROM THE COLD WATER IT HAS UPWELLED...
AND THE VERTICAL WIND SHEAR IS FORECAST TO BE GENERALLY LIGHT THROUGH 72 HR. ON THE MINUS SIDE...THE CURRENT STRUCTURE IS LIKELY NOT CONDUCIVE FOR RAPID DEVELOPMENT...AND WATER VAPOR IMAGERY SHOWS THAT LESLIE WILL CONTINUE TO HAVE ISSUES WITH DRY AIR ENTRAINMENT.
THE NEW INTENSITY FORECAST SHOW A SLOWER RATE OF DEVELOPMENT TO THE PEAK INTENSITY IN 72 HR THAN THE PREVIOUS FORECAST...CLOSE TO THE SHIPS MODEL AND BELOW THE INTENSITY CONSENSUS. AFTER 72 HR...
INCREASING SHEAR AND THE ONSET OF EXTRATROPICAL TRANSITION SHOULD CAUSE WEAKENING. EXTRATROPICAL TRANSITION IS FORECAST TO BE COMPLETE BY 120 HR.

THE WIND FIELD OF LESLIE...COMBINED WITH ITS EXPECTED SLOW MOTION... WILL GENERATE LONG-PERIOD SWELLS THAT WILL PRODUCE LARGE WAVES AND LIFE-THREATENING RIP CURRENTS ON BERMUDA AND ALONG MUCH OF THE U.S.
EAST COAST THROUGH THE WEEKEND.

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618. wxmod
Record year. Let's hope the ice comes back. I wish the oil and coal people would be a lot more helpful.

Member Since: October 4, 2011 Posts: 0 Comments: 1764
I hear you, spathy.
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Quoting ABH4Life:
Stupid question, but what is "ACE" values?

Accumulated cyclone energy (ACE) is a measure used by the National Oceanic and Atmospheric Administration (NOAA) to express the activity of individual tropical cyclones and entire tropical cyclone seasons, particularly the North Atlantic hurricane season. It uses an approximation of the energy used by a tropical system over its lifetime and is calculated every six-hour period.
Link
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Quoting AussieStorm:


Another Derecho?

Looks that way, doesn't it Aussie?
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Quoting HurrikanEB:


Accumulated Cyclone Energy

"Accumulated cyclone energy (ACE) is a measure used by the National Oceanic and Atmospheric Administration (NOAA) to express the activity of individual tropical cyclones and entire tropical cyclone seasons, particularly the North Atlantic hurricane season. It uses an approximation of the energy used by a tropical system over its lifetime and is calculated every six-hour period. The ACE of a season is the sum of the ACEs for each storm and takes into account the number, strength, and duration of all the tropical storms in the season."


Thankyou
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Quoting ABH4Life:
Stupid question, but what is "ACE" values?


Accumulated Cyclone Energy

"Accumulated cyclone energy (ACE) is a measure used by the National Oceanic and Atmospheric Administration (NOAA) to express the activity of individual tropical cyclones and entire tropical cyclone seasons, particularly the North Atlantic hurricane season. It uses an approximation of the energy used by a tropical system over its lifetime and is calculated every six-hour period. The ACE of a season is the sum of the ACEs for each storm and takes into account the number, strength, and duration of all the tropical storms in the season."

The record for a single storm is about 73.
Currently the cumulative 2012 season Ace is around 60.
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Quoting pottery:

Jamaica on a Roll, Big Time !

It's a pity that we're not able to produce similar results economically...how are you doing pottery?
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BDADUDE: Can't believe Cantore is here!!
572 listenerVT: You do know that bodes poorly for Bermuda, right? ;-)

Nope, Cantore&crew try to set up shop ~50-to-100 miles away from landfall. Ain't much sense in getting totally trashed by an eyewall when your job is reporting on the aftermath.
Bermuda is 15miles(25kilometres) wide. Given Cantore's previous crew emplacements,
Leslie's center will miss Bermuda by 35-to-85 miles... or more.
Member Since: August 21, 2007 Posts: 0 Comments: 4860
Leslie is looking so much better tonight and continues to become better organized.

Click picture for AVN Loop
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Stupid question, but what is "ACE" values?
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According the the graphic posted a few times earlier, I am in the red or 30% chance of severe weather here in Northern Essex County in Mass. To think I moved here from Texas to get away from severe weather like this....D'oh!
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Quoting tornadolarkin:
FORECAST SOUNDINGS FROM NRN NJ NWD THROUGH
THE HUDSON VALLEY SUGGEST TORNADOES ARE POSSIBLE IF DISCRETE
SUPERCELLS CAN EVOLVE AHEAD OF THE MAIN LINE AND WITH CIRCULATIONS
WITHIN THE LINE.


Agree with the SPC on that one. 1500 CAPE, high EHI, high wind shear, strengthening low pressure system. This is coming together for a very significant severe weather outbreak tomorrow. The supercells will pose a major risk for tornadoes, but the squall line itself will produce significant damage across the Northeast.



Yippie!! -___-

I'm in the heart of the Mid-Hudson Valley.. we very rarely get severe weather... looking at the radar/satellite loops, I feel that the cloud cover is advancing slightly faster than our local NWS has been calling for. Hopefully it'll limit the amount of daytime heating tomorrow afternoon... could still be interesting.
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Quoting Chicklit:
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1226 PM CDT FRI SEP 07 2012

VALID 081200Z - 091200Z

...THERE IS A MDT RISK OF SVR TSTMS FROM NERN MD/NRN DE...NWD INTO UPSTATE NY/VT/NH...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM THE CAROLINAS INTO WRN ME...

...DAMAGING SEVERE THUNDERSTORMS ARE EXPECTED ACROSS THE NORTHEASTERN U.S. SATURDAY...
POTENTIALLY SIGNIFICANT DAMAGING WIND EVENT IS EXPECTED ACROSS MUCH OF THE NERN U.S. SATURDAY. LATEST MODEL GUIDANCE...ESPECIALLY THE NAM/ECMWF...SUGGEST SHORT-WAVE TROUGH OVER THE UPPER GREAT LAKES WILL DIG INTO LOWER MI BY 08/12 BEFORE EJECTING NEWD IN A NEGATIVELY TILTED FASHION AND DEEPENING OVER SERN ONTARIO/WRN QUEBEC. 90-120M 12HR HEIGHT FALLS WILL SPREAD ACROSS WRN/UPSTATE NY DURING THE DAY ENSURING A STRONGLY FORCED AND CONVECTIVELY-ACTIVE COLD FRONT. THIS EVOLUTION SUGGESTS A FRONTAL INTRUSION THAT WILL INDUCE A BAND OF SEVERE THUNDERSTORMS AS IT SURGES ACROSS THE NRN MIDDLE ATLANTIC REGION INTO NEW ENGLAND.

ALL INDICATIONS FAVOR A SQUALL ALONG THE WIND SHIFT AT SUNRISE FROM SRN ONTARIO SWD ACROSS OH...TRAILING INTO THE TN VALLEY. THIS ACTIVITY IS EXPECTED TO INTENSIFY AS IT MOVES INTO WRN NY/PA...ESPECIALLY BY 18Z AS BOUNDARY LAYER BEGINS TO WARM.
ALTHOUGH FORECAST LAPSE RATES ARE NOT PARTICULARLY STEEP BOUNDARY LAYER AIRMASS IS FAIRLY MOIST ATTM WITH UPPER 60S-70F SFC DEW POINTS IN PLACE ACROSS THE MIDDLE ATLANTIC REGION. THERE IS LITTLE REASON TO BELIEVE THIS AIRMASS WILL NOT SPREAD NWD ACROSS PA/NJ INTO UPSTATE NY AHEAD OF THE COLD FRONT AND AMPLE MOISTURE/INSTABILITY WILL SPREAD NWD TOWARD THE CANADIAN BORDER TO SUPPORT ROBUST UPDRAFTS WITHIN A STRONGLY SHEARED ENVIRONMENT.
OF PARTICULAR CONCERN IS THE EXPECTED MID LEVEL JET THAT SHOULD INTENSIFY AS IT EJECTS ACROSS WRN PA TO SPEEDS IN EXCESS OF 70KT OVER UPSTATE NY BY 09/00Z. WITH DEEPENING SFC LOW OVER SERN ONTARIO FORECAST SHEAR PROFILES BECOME QUITE FAVORABLE FOR SUSTAINING ORGANIZED UPDRAFTS. WHILE A DAMAGING SQUALL LINE IS EXPECTED ALONG
THE ADVANCING COLD FRONT...ENVIRONMENTAL SHEAR WILL BECOME QUITE FAVORABLE FOR PRE-FRONTAL SUPERCELLS AND EMBEDDED SUPERCELLS WITHIN THE MAIN SQUALL LINE. FORECAST SOUNDINGS FROM NRN NJ NWD THROUGH THE HUDSON VALLEY SUGGEST TORNADOES ARE POSSIBLE IF DISCRETE SUPERCELLS CAN EVOLVE AHEAD OF THE MAIN LINE AND WITH CIRCULATIONS WITHIN THE LINE. LATEST MODEL GUIDANCE SUGGESTS THE BACK EDGE OF THE PRIMARY SQUALL LINE WILL ADVANCE INTO THE HUDSON VALLEY BY LATE AFTERNOON TRAILING SWWD INTO CNTRL VA BY 09/00Z WITH SUBSEQUENT MOVEMENT ACROSS MUCH OF NEW ENGLAND BY 06Z.

Sorry this is so long, but looks like a real severe weather threat for the NE US on Saturday.


Another Derecho?
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Quoting nigel20:
Jamaica has created history by beating the US 2-1 in international football (soccer) for the first time:-)

Jamaica on a Roll, Big Time !
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Total ACE (Atlantic);
60.7

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DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1226 PM CDT FRI SEP 07 2012

VALID 081200Z - 091200Z

...THERE IS A MDT RISK OF SVR TSTMS FROM NERN MD/NRN DE...NWD INTO UPSTATE NY/VT/NH...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM THE CAROLINAS INTO WRN ME...

...DAMAGING SEVERE THUNDERSTORMS ARE EXPECTED ACROSS THE NORTHEASTERN U.S. SATURDAY...
POTENTIALLY SIGNIFICANT DAMAGING WIND EVENT IS EXPECTED ACROSS MUCH OF THE NERN U.S. SATURDAY. LATEST MODEL GUIDANCE...ESPECIALLY THE NAM/ECMWF...SUGGEST SHORT-WAVE TROUGH OVER THE UPPER GREAT LAKES WILL DIG INTO LOWER MI BY 08/12 BEFORE EJECTING NEWD IN A NEGATIVELY TILTED FASHION AND DEEPENING OVER SERN ONTARIO/WRN QUEBEC. 90-120M 12HR HEIGHT FALLS WILL SPREAD ACROSS WRN/UPSTATE NY DURING THE DAY ENSURING A STRONGLY FORCED AND CONVECTIVELY-ACTIVE COLD FRONT. THIS EVOLUTION SUGGESTS A FRONTAL INTRUSION THAT WILL INDUCE A BAND OF SEVERE THUNDERSTORMS AS IT SURGES ACROSS THE NRN MIDDLE ATLANTIC REGION INTO NEW ENGLAND.

ALL INDICATIONS FAVOR A SQUALL ALONG THE WIND SHIFT AT SUNRISE FROM SRN ONTARIO SWD ACROSS OH...TRAILING INTO THE TN VALLEY. THIS ACTIVITY IS EXPECTED TO INTENSIFY AS IT MOVES INTO WRN NY/PA...ESPECIALLY BY 18Z AS BOUNDARY LAYER BEGINS TO WARM.
ALTHOUGH FORECAST LAPSE RATES ARE NOT PARTICULARLY STEEP BOUNDARY LAYER AIRMASS IS FAIRLY MOIST ATTM WITH UPPER 60S-70F SFC DEW POINTS IN PLACE ACROSS THE MIDDLE ATLANTIC REGION. THERE IS LITTLE REASON TO BELIEVE THIS AIRMASS WILL NOT SPREAD NWD ACROSS PA/NJ INTO UPSTATE NY AHEAD OF THE COLD FRONT AND AMPLE MOISTURE/INSTABILITY WILL SPREAD NWD TOWARD THE CANADIAN BORDER TO SUPPORT ROBUST UPDRAFTS WITHIN A STRONGLY SHEARED ENVIRONMENT.
OF PARTICULAR CONCERN IS THE EXPECTED MID LEVEL JET THAT SHOULD INTENSIFY AS IT EJECTS ACROSS WRN PA TO SPEEDS IN EXCESS OF 70KT OVER UPSTATE NY BY 09/00Z. WITH DEEPENING SFC LOW OVER SERN ONTARIO FORECAST SHEAR PROFILES BECOME QUITE FAVORABLE FOR SUSTAINING ORGANIZED UPDRAFTS. WHILE A DAMAGING SQUALL LINE IS EXPECTED ALONG
THE ADVANCING COLD FRONT...ENVIRONMENTAL SHEAR WILL BECOME QUITE FAVORABLE FOR PRE-FRONTAL SUPERCELLS AND EMBEDDED SUPERCELLS WITHIN THE MAIN SQUALL LINE. FORECAST SOUNDINGS FROM NRN NJ NWD THROUGH THE HUDSON VALLEY SUGGEST TORNADOES ARE POSSIBLE IF DISCRETE SUPERCELLS CAN EVOLVE AHEAD OF THE MAIN LINE AND WITH CIRCULATIONS WITHIN THE LINE. LATEST MODEL GUIDANCE SUGGESTS THE BACK EDGE OF THE PRIMARY SQUALL LINE WILL ADVANCE INTO THE HUDSON VALLEY BY LATE AFTERNOON TRAILING SWWD INTO CNTRL VA BY 09/00Z WITH SUBSEQUENT MOVEMENT ACROSS MUCH OF NEW ENGLAND BY 06Z.

Sorry this is so long, but looks like a real severe weather threat for the NE US on Saturday.
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Quoting guygee:
Agreed. But it is still a good source for educational material and research. There are some fairly advanced topics covered in mathematics and science. I am not going to put down Wikipedia, especially when the greedy publishers of scientific literature have the gall to charge $20-$50 per paper.

Academics only get published if they sign away their copyright to those publishers, and they never see a penny of that money...in fact there is often a nominal "page charge", for example it could be something like a couple hundred dollars for every page over five.

Society benefits when cutting-edge scientific knowledge is freely available to the general public. Society does not benefit from the greedy publishers and various scientific societies that leech off of academia.

Academic publishing is a racket.

Wikipedia is great for this blog. I can always check out any Wiki articles to see how well they are sourced.

I wish people would cite their sources on here more often. I generally don't believe anything anyone says on here just because they said it. I learn a lot from the blog, but the face value of everything is just opinion. Citing sources is a big plus. Not everyone does that unfortunately.

The NWS field office web sites are great, too. I'm surprised at the number of people posting questions on here that are readily answered by the local NWS office website.

Time to start the rinse cycle.
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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.