posted
SatelliteInfraredLoop -- TrackingMap -- OceanTemperature&EnergyPotential (click to enlarge) The links above automaticly refresh upon each new visit. The links below are useful for picturing the storm's position. Latitude&LongitudeMap (click to change scale) -- CaribbeanMap (click to enlarge) In using the Latitude&LongitudeMap: latitude numbers South are negative, and preceded with a - sign longitude numbers West are negative, eg 62.7degreesWest should be typed in as -62.7 with latitude numbers North and longitude numbers East both being positive, ie typed as written.
NationalHurricaneCenter (archive) TropicalDepression27 AdvisoryNumber01 10pmEasternStandardTime(HatrackTime)13November2005 The center of TropicalDepression27 was located near latitude 13.5North...longitude 62.7West 100miles/161kilometres west of St.Vincent [island north of eastern Venezuela] And is moving WestNorthWest near 10mileperhour/16kilometresperhour MaximumSustainedWinds are near 35mph/56kph and could become a TropicalStorm on Monday MinimumAirPressure at the depression's center is estimated to be 1007millibars/29.74inches
posted
The TropicalDepression was first reported last night at 10pmEST.
According to the latest NHC TropicalDepression27 DiscussionNumber03 at 10amEST(HatrackTime)14November2005, "...ocean temperatures do not provide any limiting factor..." to continued growth of the storm. If you take a look at the latest SeaSurfaceTemperatureMap, all the Caribbean waters are above the 26degreesCelsius/79degreesFahrenheit that will provide sufficient energy for storm growth.
What is happening right now is that the tropical depression is trying to wrap itself around a center. Essentially, it's trying to build an eye, a "chimney"* from the warm surface waters to the cold air high up in the atmosphere. The eye is currently slow to form because windshear at the higher altitudes is knocking the top off the "chimney" before it can reach the coldest air. The greater the temperature differential between the surface waters and the air at the top of the "chimney", the greater the updraft. The greater the partial vacuum (the updraft) at the surface, the faster the storm picks up more energy from the warm sea.
However, the discussion points out that, "The convection is still rather deep and persistent...and it appears to be in the process of forming a curved band that could soon wrap around the low level center. The cyclone appears close to becoming a tropical storm." "The ShipsGuidance...model diagnoses [wind]shear...for the next couple of days and does not forecast a tropical storm [for] 36hours. It then forecasts a storm no stronger than ~50knots/~57mph/~92kph in the next five days...But [the ShipsGuidance model] could be overestimating the impacts of shear... The GFDL [model]...forecast[s] intensification to a hurricane in ~3days, peaking at 110knots/~126mph/~204kph in ~4days." ie It could become an upper level Category3, a major hurricane. "Given...a system still in the formative stages, the intensity forecast is highly uncertain."
* Since warm air rises, the "chimney" will provide a route for the warm air to rise with minimal mixing with the cooler air outside the chimney. Thereby, the warm air stays warmer and rises faster than it would if it were cooled by outside air. And just as in a real fireplace, the warm air provides an updraft, a partial vacuum which sucks more air toward the base of the chimney. In the case of a tropical cyclone's eye, the "chimney" sucks wind over the warm surface toward the base of the eye, thereby picking up warm water vapor which in turn warms the air. The warmed air in turn goes up the chimney, and the cycle continues repeating itself.
posted
That's why I read the DrudgeReport. Whatever your feelings about his political leanings, his headlines, or the reliablity of some of his linked articles, Drudge has a better nose for what is going to be the most-discussed news than almost anyone else in the business.
Posts: 8501 | Registered: Jul 2001
| IP: Logged |
posted
Drudge may be guilty of misleadingly politicizing his headlines, but the articles he links to are usually fairly balanced. And when he wants to kick up a stinkeroo, Drudge doesn't hafta "make it up himself." There are plenty of papers/magazines/blogs from which to choose nonsensical "news" links.
Posts: 8501 | Registered: Jul 2001
| IP: Logged |
quote:Originally posted by Farmgirl: Do you think the waters are warm enough still to make it reach tropical storm or hurricane strength?
FG
The waters in the Carribean where this tropical depression is located are a bit over 85°F. That's easily warm enough for this to develope into a tropical storm and possibly a hurricane. We shall see.
Fortunately for the people on the gulf coast, the waters in the gulf of Mexico are now cooler so a massive hurricane would loose power crossing those waters. This doesn't however help the people in the Carribean.
Posts: 12591 | Registered: Jan 2000
| IP: Logged |
posted
If you take a look at the SatelliteInfraredLoop in the first posting, you'll notice an large anticyclonic movement of clouds spinning between Florida's eastern coast and north of the Caribbean islands. Earlier today, that anticyclone's southern edge was moving in the same westward direction as the TD27cyclone's northern edge in near contact. Since then, a strong eastward windshear has developed between the southern edge of that anticyclone and the northern edge of the TD27 cyclone. Because that shear's eastward wind is in opposition to the westward wind on TD27's northern edge, TD27's western sector has been strongly battered by windshear. Causing TD27 itself to become weaker and less organized.
So at present, the western Caribbean's warmer waters are providing energy for that windshear to suppress TD27's "chimney"building eye formation process.
posted
Yep. It's baa-aaack... TropicalDepression27 has returned from the grave as TropicalStormGamma NationalHurricaneCenter IntermediateAdvisoryNumber12A 6pmCentralStandardTime/7pmEST(HatrackTime)Friday 18Nov2005 The center of TropicalStormGamma was estimated near latitude 16.2North : longitude 85.7West Moving erratically toward the westNorthwest near 4mph/6kph Maximum sustained winds are near 45mph/72kph TropicalStorm force winds extend outward up to 85miles/136kilometres mainly to the north of center Estimated minimum central air pressure is 1006millibars/29.71inches
posted
They're now showing it heading eastward across southern Cuba out into the Atlantic. Stay tuned as the forecast track is drastically changing all the time. Yesterday they were predicting it eventually to go across Florida.
posted
Though not as interesting* as the SatelliteInfraredLoop, here's a JAVA-animated stormtrack showing the life&death of TropicalDepression27, and it's subsequent resurrection as TropicalStormGamma.
I was watching the SatelliteInfraredLoop as a huge low pressure system -- spanning across the Nicaragua-Honduras border into both the Pacific and the Caribbean -- sent windshear into the northern sector of TD27. Slowing and disappating TD27's entire western half by the time TD27's center reached directly south of westernmost Haiti / easternmost Cuba. At which point, the NationalHurricaneCenter declared that TD27 was moribund and no further updates would be forthcoming. Then, the coldest section with the fastest updraft -- represented in the (infrared) animation as a black dot in the midst of red -- ie the former center of TD27 *zip*ped across the Caribbean from it's position south Haiti to join that huge low pressure system's center, which had drifted offshore of northeastern Honduras. And the remnant of TD27 merged/disappeared within that larger weather system.
A day and a half later, the NHC declared that TropicalDepression27 had reformed as TropicalStormGamma.
* The earlier (infrared) animation of TD27/TSGamma seems to be unavailable for linking. If TD27's/TSGamma's (JAVAed) stormtrack link quits working, it'll reappear in Terrapin's2005archive.
posted
TropicalStorm Delta (archives) reached maximum sustained winds of 60knots/69mph/111kph, only 5mph/8kph under hurricane force. Delta hit the Canary islands with gusts up to 75mph/122kph -- killing seven and taking out the electricity grid -- then brought much needed rain to Morocco upon African landfall.
The center of HurricaneEpsilon is near Latitude33.7North : Longitude 48.2West With maximum sustained winds near 75mph/121kph HurricaneForce winds extend outward to 17miles/28kilometres from the center TropicalStormForce winds extend outward to 115miles/185kilometres Estimated minimum central air pressure is 987millibars
Posts: 8501 | Registered: Jul 2001
| IP: Logged |
posted
Looking at 33.7North 48.2West on this SeaSurfaceTemperature map shows that Epsilon gained hurricane strength over ocean temperatures below 26degreesCelsius/79degreesFahrenheit, the standard "minimum" temperature needed to make hurricanes. Epsilon is the second tropical storm to grow into a hurricane over "below minimum temperature" waters during this season.
posted
It did decrease to a 60knot/69mph/111kph TropicalStorm by AdvisoryNumber20 at 4amEST on Sunday 04Dec05. Then roared back to a 75knot/86mph/139kph Hurricane by DiscussionNumber21 at 10amEST(HatrackTime)Sunday04December05, leading to "There are no clear explanations -- and I am not going to make one up -- to explain the recent strengthening of Epsilon...I still have to make an intensity forecast and the best bet...is to predict weakening... ...and Epsilon will likely become a remnant low. I've heard that about Epsilon before. Haven't you?" I love Forecaster Avila
posted
Sorry for not answering earlier, Farmgirl, I've been waitng for the Zeta archive to come online. The link was completely down when you posted, and the archive still doesn't link to any reports past 4pmEST 31Dec05. Because the prediction process and the forecasters' reactions are in some ways the more interesting part, I'll start with
08Dec05 HurricaneEpsilon Discussion#37, "I hope this is the end of the longlasting 2005 hurricane season. Forecaster Avila" 30Dec05 HurricaneZeta Discussion#02, "Although the atmosphere seems to want to develop tropical storms ad nauseum...the calender will shortly put an end to the use of the Greek alphabet to name them. Forecaster Franklin"
and delay comment until the archive is fully back up, or the NHC declares Zeta to be over.
quote: Zeta again strengthened into a tropical storm Thursday and could break the record for the storm lasting the longest into January since record keeping began in 1851
Printer-friendly view of this topic
![[Big Grin]](biggrin.gif)
I love Forecaster Avila ![[Smile]](smile.gif)
