Rafael intensifying, but is pulling away from the Lesser Antilles
Tropical Storm Rafael is intensifying, but is headed northwards away from the Lesser Antilles Islands, after bringing gusty winds and heavy rains to the islands over the past two days. Three-day rainfall amounts of 2 - 3" were common over the Leeward Islands, but the winds mostly stayed below tropical storm-force. Here are some of the peak wind gusts from Rafael and rainfall totals from Oct 11 through 10 am EDT October 14:
Barbados, 47 mph, 0.81"
Antigua: 37 mph, 3.66"
Martinique: 30 mph, 3.10"
St. Lucia: 39 mph, 2.07"
St. Martin: 45 mph, 2.56"
Guadaloupe: 36 mph, 2.51"
Dominica: 25 mph, 2.68"
St. Kiits: 34 mph, 3.47"
Satellite loops show that Rafael has gotten much more organized late this morning, with an impressive spiral band with very heavy thunderstorms to the east of the center. Heavy thunderstorms with cold cloud tops are forming over the center, the hallmark of an intensifying tropical storm. The Hurricane Hunters found a central pressure of 997 mb, and winds at their 5,000-foot flight level of 68 mph this morning. Rafael is experiencing a moderate 10 - 20 knots of wind shear.
Figure 1. Morning satellite image of Tropical Storm Rafael.
Forecast for Rafael
Wind shear is expected to remain in the moderate range through Tuesday, which should allow Rafael to intensify into a Category 1 hurricane. Heavy rains will continue over the Leeward Islands today and diminish on Monday. A tropical storm watch has been posted for Bermuda, which is at risk of seeing tropical storm-force winds from Rafael on Tuesday. The 11 am EDT wind probability forecast from NHC gave Bermuda a 40% chance of experiencing tropical storm-force winds between Monday night and Wednesday morning, and a 6% chance of experiencing hurricane-force winds. The models are pretty tightly clustered showing a track for Rafael to the east of Bermuda, which would put the island on the weaker (left front) side of the storm.
Tropical Storm Paul forms in the Eastern Pacific
Tropical Storm Paul formed yesterday in the East Pacific, and is headed northwards towards Mexico's Baja Peninsula. Paul's formation brings this year's tally of named storms in the East Pacific to sixteen, making 2012 just the third year since records began in 1949 that both the Eastern Pacific and Atlantic have had at least sixteen named storms. The other years were 2003 and 2008.
Figure 2. MODIS satellite image of Tropical Cyclone Anais in the Southwest Pacific taken at 2:05 am EDT Sunday October 14, 2012. At the time, Anais was a Category 3 storm with 120 mph winds, the strongest tropical cyclone ever observed in the Southwest Pacific so early in their hurricane season. Image credit: NASA.
A rare early-season major tropical cyclone in the Southwest Indian Ocean
It's springtime in the Southern Hemisphere, where an unusual tropical cyclone has formed--Tropical Cyclone Anais, which hit Category 3 strength with 120 mph winds. According to Meteo France in La Reunion Island, Anais is the earliest major hurricane to form during the Southwest Indian Ocean's tropical cyclone season, which typically runs from November to May. Anais' formation in mid-October is akin to getting a major hurricane in the Atlantic during April, something which has never occurred (the earliest major hurricane on record in the Atlantic occurred on May 21, 1951.) Anais is the second earliest hurricane of any kind to form so early in the Southwest Indian Ocean tropical cyclone season, after Tropical Cyclone Blanche of October 10, 1969. Anais may reach Category 4 strength before cooler waters and increased wind shear weaken the storm as it approaches Madagascar.
Jeff Masters
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Kuena would have been part of the 2011-12 cyclone season since it was in June and their season ends in May (it would be like a December storm for us) also I'd like to Point out that their season starts November 1st so Anais would be analagous to a May major hurricane, not an April one (which is still very impressive just not unheard of)
Drought, aerosols & global dimming due to air pollution is a pretty interesting subject to study. Some of the drought cycles we thought we understood are looking in doubt due to aerosol studies.
Water vapor has made for another unfortunate feedback loop to a warmer world. Atleast you understand how different chemical compounds retain specific amounts of heat.
What is the difference between sea ice area and extent?
Area and extent are different measures and give scientists slightly different information. Some organizations, including Cryosphere Today, report ice area; NSIDC primarily reports ice extent. Extent is always a larger number than area, and there are pros and cons associated with each method.
A simplified way to think of extent versus area is to imagine a slice of swiss cheese. Extent would be a measure of the edges of the slice of cheese and all of the space inside it. Area would be the measure of where there is cheese only, not including the holes. That is why if you compare extent and area in the same time period, extent is always bigger. A more precise explanation of extent versus area gets more complicated.
Extent defines a region as “ice-covered” or “not ice-covered.” For each satellite data cell, the cell is said to either have ice or to have no ice, based on a threshold. The most common threshold (and the one NSIDC uses) is 15 percent, meaning that if the data cell has greater than 15 percent ice concentration, the cell is considered ice covered; less than that and it is said to be ice free. Example: Let’s say you have three 25 kilometer (km) x 25 km (16 miles x 16 miles) grid cells covered by 16% ice, 2% ice, and 90% ice. Two of the three cells would be considered “ice covered,” or 100% ice. Multiply the grid cell area by 100% sea ice and you would get a total extent of 1,250 square km (482 square miles).
Area takes the percentages of sea ice within data cells and adds them up to report how much of the Arctic is covered by ice; area typically uses a threshold of 15%. So in the same example, with three 25 km x 25 km (16 miles x 16 miles) grid cells of 16% ice, 2% ice, and 90% ice, multiply the grid cell areas that are over the 15% threshold by the percent of sea ice in those grid cells, and add it up. You would have a total area of 662 square km (255.8 square miles).
Scientists at NSIDC report extent because they are cautious about summertime values of ice concentration and area taken from satellite sensors. To the sensor, surface melt appears to be open water rather than water on top of sea ice. So, while reliable for measuring area most of the year, the microwave sensor is prone to underestimating the actual ice concentration and area when the surface is melting. To account for that potential inaccuracy, NSIDC scientists rely primarily on extent when analyzing melt-season conditions and reporting them to the public. That said, analyzing ice area is still quite valuable. Given the right circumstances, background knowledge, and scientific information on current conditions, it can provide an excellent sense of how much ice there really is “on the ground.”
Source info: NSIDC is part of the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado at Boulder. The University and CIRES provide a collaborative environment and support for our research. NSIDC's research and scientific data management activities are supported by NASA, the National Science Foundation (NSF), the National Oceanic and Atmospheric Administration (NOAA), and other federal agencies, through competitive grants and contracts.
..RAFAEL EXPECTED TO BECOME A HURRICANE LATER TODAY... ...TROPICAL STORM WARNING ISSUED FOR BERMUDA...
11:00 AM AST Mon Oct 15
Location: 23.0°N 65.7°W
Moving: NNW at 9 mph
Min pressure: 985 mb
Max sustained: 70 mph
What could have come in to not declare it a hurricane?
Thanks GT..a long way out but always watching!
A sheared cyclone does not translate into a sub-tropical cyclone. Data from the HH showed temperatures were high in the cyclone, and the winds were centered over the CoC with a developing eyewall, not characteristic of a sub-tropical storm at all. There was nothing cold core about it, it didn't align itself with any ULLs, and -80C convection was firing over the center. Just a somewhat sheared strong TS.
HURRICANE PAUL DISCUSSION NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL EP162012
800 AM PDT MON OCT 15 2012
PAUL IS INTENSIFYING. THE CLOUD PATTERN OF THE CYCLONE IS BECOMING
AN INCREASINGLY SYMMETRIC CENTRAL DENSE OVERCAST WITH VERY COLD
CLOUD TOP TEMPERATURES. AN EYE SEEN IN MICROWAVE IMAGERY EARLIER
HAS BECOME INTERMITTENTLY VISIBLE IN CONVENTIONAL IMAGERY. DVORAK
CLASSIFICATIONS HAVE INCREASED TO T4.5 FROM BOTH SATELLITE AGENCIES
AT 1200 UTC...AND THE INITIAL INTENSITY ESTIMATE IS INCREASED TO 80
KT.
PAUL HAS ACCELERATED DURING THE PAST SEVERAL HOURS AND THE INITIAL
MOTION ESTIMATE IS 010/11. THE CYCLONE SHOULD BE STEERED NORTHWARD
OR NORTH-NORTHEASTWARD BY DEEP-LAYER SOUTHERLY FLOW EAST OF A
MID-/UPPER-LEVEL TROPOSPHERIC LOW CUTTING OFF NEAR 23N 118W DURING
THE NEXT DAY OR TWO. AFTER 48 HOURS...PAUL SHOULD DECELERATE AND
TURN NORTHWESTWARD AND THEN WEST-NORTHWESTARD AROUND THE CLOSED
LOW. THE TRACK GUIDANCE IS IN GOOD AGREEMENT THROUGH 48 HOURS AND
HAS AGAIN SHIFTED FARTHER EASTWARD. THE OFFICIAL FORECAST IS
ADJUSTED IN THAT DIRECTION BUT IS NOT QUITE AS FAR EAST AS THE
ECMWF AND GFS SOLUTIONS.
ALTHOUGH SEA SURFACE TEMPERATURES BENEATH PAUL ARE ALREADY GRADUALLY
DECREASING...ENVIRONMENTAL FACTORS SHOULD REMAIN FAVORABLE FOR
ADDITIONAL INTENSIFICATION FOR ABOUT 12 HOURS OR SO. AFTER THAT
TIME...INCREASING SOUTH-SOUTHWESTERLY SHEAR ASSOCIATED WITH THE
CLOSED LOW TO THE WEST OF PAUL AND EVEN COOLER WATERS SHOULD RESULT
IN STEADY WEAKENING. THE WEAKENING COULD BECOME MORE RAPID AFTER 48
HOURS WHEN THE VERTICAL SHEAR IS FORECAST TO INCREASE FURTHER...AND
THE CYCLONE COULD DECOUPLE AT THAT TIME. THE NHC INTENSITY FORECAST
HAS BEEN ADJUSTED UPWARD IN THE SHORT TERM TO ACCOUNT FOR THE
CURRENT INTENSIFICATION.
THE EASTWARD SHIFT OF THE TRACK...ALONG WITH THE FORECAST WIND
RADII...REQUIRES THE ISSUANCE OF A TROPICAL STORM WARNING FOR A
PORTION OF THE WEST COAST OF THE BAJA PENINSULA AND AN EXTENSION OF
THE TROPICAL STORM WATCH.
FORECAST POSITIONS AND MAX WINDS
INIT 15/1500Z 17.3N 114.7W 80 KT 90 MPH
12H 16/0000Z 19.1N 114.2W 85 KT 100 MPH
24H 16/1200Z 21.6N 113.4W 75 KT 85 MPH
36H 17/0000Z 24.2N 113.2W 65 KT 75 MPH
48H 17/1200Z 26.0N 114.0W 50 KT 60 MPH
72H 18/1200Z 28.4N 116.2W 30 KT 35 MPH
96H 19/1200Z...DISSIPATED
$$
FORECASTER KIMBERLAIN/BROWN
The ATCF is the NHC so, or atleast the feed they put into the models every cycle (00z, 06z, 12z, 18z). Rafael will be a hurricane later today, but they upgraded it to a hurricane and then brought it back down to TS strength.
Good point Taz~ You can see how the big C here for current is deeper into the warm core (tropical) region then Rafael was in the beginning (A). Interesting gfs forecasts it to go subtropical a bit then back toward more tropical..
If it was really that bad they wouldn't have power and therefore would not be able to access the site anyways.
Some? You mean all. (at least all of the GFS model runs)
From the NHC: Early the next day, the separation between Lee and the upper-level low
decreased and the two systems became co-located around 0600 UTC 3 September. During this
time, the overall satellite appearance of Lee began to take on the appearance of a subtropical
cyclone.
Key part, Lee merged with the ULL and became sub-tropical. There was no such occurrence with Rafael.
People in the impacted states couldnt access this site during Isaac either but yet we still talked about it? moving on..
70kt flight level winds doesn't support 65kt surface winds. 60kt sounds reasonable.
If they weren't always so conservative, there'd be no need to waste time doing a post-season analysis of all these storms
And in other climate news, Arctic sea ice area set a new record anomaly yesterday at 2.7 million square kilometers below the average for the date.
Lol, but the main point of this argument was that we should keep the global warming posts off here so people in the islands could find information concerning the storm.
But yeah, anyways, moving on.
I get the ukmet, JMAN & ECMM are of little hope:)
The rest tend to over due for our basin when they look like that..except if mjo is gonna get mad here it's usually Sept or Oct.
I went with 3, maybe more storms for Oct because of the MJO coming back around. We've already had 2.
Keep, that image is two days old.
Oops. I meant 80 knots.
I did, it shows A - C as tropical, and Z as sub-tropical. That means the GFS is forecasting it to go sub-tropical, more than likely extra-tropical. It was never at any point a sub-tropical cyclone.
They were 80kts.
Does look less like the number nine than it has too. Something leaning at all nine shaped tends to be cooler core that a nice fat round exploding tropical system..regardless of cause.
Here are the readings by recon early this morning on the first pass.
Maximum Wind Outbound: 81kts (~ 93.2mph) in the northeast quadrant at 10:55:00Z
Maximum Flight Level Wind: 81kts (~ 93.2mph) in the northeast quadrant at 10:55:00Z
I'm sure they noted it. It's been obvious all the while that it wasn't deeply warm core in the beginning but it has been none the less warm core so far. Hence the tropical & not sub-tropical designation.
As of last month, temps in the US had to average in the coldest 1/3 of all years recorded since about 1900 for us to not have the warmest year on record. This knocks out yet another month where we would have needed below normal temps. A more and more anomalous cold spell is going to be required the closer we get to the end of the year.
The increases in extreme weather are consistent with the predictions made for a warmer climate. But extreme weather over a few days, or a month, or even a full year are not exactly direct evidence of climate change or global warming.
Of course the increase in extremes, the increase in temperatures, the loss of Arctic sea ice, the ocean acidification, the accelerating loss of Greenland icepack, the accelerating loss of land glaciers hasn't just happened in a day or a month or a single year.
Such things have been happening, unequivocally, over long enough time scales to be classified as climate... as in decades. And when these things continue, it is correct to say that the observations are consistent with the observed trends. Not direct evidence for, but consistent with.
22.1n65.1w has been re-evaluated&altered
ZSA-SanSalvador :: GDT-GrandTurk :: NGD-Anegada :: AXA-Anguilla
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