Hawaii braces for Felicia; 99L near the Cape Verdes Islands may develop
A strong tropical wave (99L) is just south of the Cape Verdes Islands, 800 miles off the coast of Africa. This morning's QuikSCAT pass showed a nearly closed surface circulation, stretched out along one axis. The satellite saw winds of up to 45 mph in a band of heavy thunderstorms well south of the Cape Verdes Islands. The islands have seen winds of only 10 - 15 mph and some occasional rain showers thus far from the disturbance. Heavy thunderstorm activity associated with 99L died down this morning, but appears to be making a comeback late this morning. Wind shear is moderate, about 10 knots, and sea surface temperatures are moderately warm, about 27 - 28°C. There is a large area of dry air to 99L's north that is interfering with the storm's organization, though.
Figure 1. Current satellite image of disturbance 99L.
Wind shear is expected to be moderate, 5 - 15 knots, through Wednesday. SSTs will remain relatively constant at 27°C, but the dry, stable air of the Saharan AIr Layer (SAL) to 99L's north will be problem for it. NHC has given 99L a moderate (30 - 50% chance) of developing into a tropical depression by Wednesday morning, which is a reasonable forecast. Most of the models show some weak development, but none of them predict 99L will become a hurricane. It is too early to say if 99L will recurve north of the Lesser Antilles Islands or not, since it will be at least 5 days before the storm makes it that far. It is unusual, though, for storms forming this far north to make it all the way across the Atlantic to hit the Lesser Antilles Islands.
The GFS and ECMWF models are predicting the possible development of a new tropical wave coming off the coast of Africa late this week.
Felicia continues to weaken, but is a flash flooding threat to Hawaii
Tropical Storm Felicia has weakened steadily over the past 24 hours, thanks to cool sea surface temperatures and increasing shear. Recent satellite loops show that strong upper-level winds from the west have pushed the storm's heavy thunderstorm activity to the northeast side of the center, exposing the surface center as a swirl of low clouds. Felicia's relatively meager heavy thunderstorm activity is steadily moving away from the center of the storm.
Figure 2. History of hurricane activity over Hawaii since 1950. Hawaii islands have been hit by only 9 tropical cyclones of tropical depression or greater strength, with 4 others passing withing 75 miles of an island. Image credit: NOAA Coastal Services Center.
Sea surface temperatures (SSTs) under Felicia are 25°C, well below the 26°C threshold typically needed to sustain a hurricane. SSTs will slowly increase to 26°C by Tuesday. Wind shear has increased to a high 30 knots, and is expected to increase further to 40 knots by Tuesday. The high shear combined with the cool SSTs should continue to weaken Felicia today. I give a 30% chance that the shear will completely rip away Felicia's heavy thunderstorm activity by the time the storm reaches Hawaii, leaving only a swirl of low-level clouds that will not cause significant flooding problems. The wind speed probabilities forecast shows about a 25% chance Felicia will still be a weak tropical storm at 3 am Hawaiian time Tuesday morning, and a 15% chance the storm will have dissipated. If Felicia does hold together that long, it would be only the tenth tropical cyclone of tropical depression or higher strength to affect the islands since 1950 (Figure 2). Large swells from Felicia are already affecting the Big Island, and a high surf warning has been posted for east-facing shores of the Big Island and other Hawaiian islands. Felicia or its remnants may bring heavy rain, flash flooding, and mud slides to the islands beginning this afternoon, and a Flash Flood Watch has been posted for most of the islands.
Links to follow:
Long range radar from the Big Island
Wundermap for Hawaii
I'll have an update Tuesday morning.
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Looks like 99L is done with it's reorg. Back to putting on a show.
Good Point. Time will only tell...
And really, once you are able to tune out the drama and white noise of the blog that surrounds these formation events, I think that watching cyclogenesis (or, as has been the case this year, aborted cyclogenesis) is at least as interesting as watching a healthy hurricane grow. Perhaps more so. It's the one part of tropical cyclone forecasting that is least understood and probably has the poorest forecast verification record. The more eyes on it, the better.
Scientists debated two theories to explain how the safe zone was cleared. The prominent theory stated radio waves from space, generated by turbulence in the zone, cleared it. An alternate theory, confirmed by this research, stated radio waves generated by lightning were responsible. "We were fascinated to discover evidence that strongly supported the lightning theory, because we usually think about how the space environment affects the Earth, not the reverse," Green said.
The flash we see from lightning is just part of the total radiation it produces. Lightning also generates radio waves. In the same way visible light is bent by a prism, these radio waves are bent by electrically charged gas trapped in the Earth's magnetic field. That causes the waves to flow out into space along the Earth's magnetic field lines.
According to the lightning theory, radio waves clear the safe zone by interacting with the radiation belt particles, removing a little of their energy and changing their direction. This lowers the mirror point, the place above the polar regions where the particles bounce. Eventually, the mirror point becomes so low; it is in the Earth's atmosphere. When this happens, the radiation belt particles can no longer bounce back into space, because they collide with atmospheric particles and dissipate their energy.
What category, his seems like a three.
WOW! That explains a lot of things. Lol.
Interesting, thanks. Amazing power in those storms.
Hurricane Rita, amazingly this does not look like an atom bomb going off from sattilite, but what if you were to pack all the energy stored and all the power in nukes, THATS what the power would be.
This also came from Weather Underground here in this VERY blog!
"The results are important, because a better understanding of the radiation belts will help modellers forecast space weather more accurately, helping to protect both astronauts and satellites from radiation hazards."
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0637 UTC TUE AUG 11 2009
090811 0600
...INITIAL CONDITIONS...
LATCUR = 14.5N LONCUR = 27.9W DIRCUR = 275DEG SPDCUR = 11KT
LATM12 = 14.4N LONM12 = 25.7W DIRM12 = 270DEG SPDM12 = 9KT
LATM24 = 14.3N LONM24 = 24.0W
WNDCUR = 25KT RMAXWD = 30NM WNDM12 = 25KT
CENPRS = 1008MB OUTPRS = 1011MB OUTRAD = 125NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM
The Little Invest that Could!
See this:
000
WHXX04 KWBC 110520
CHGQLM
ATTENTION...NATIONAL HURRICANE CENTER
NCEP COUPLED GFDL HURRICANE MODEL FORECAST MADE FOR
TROPICAL DEPRESSION INVEST 99L
INITIAL TIME 0Z AUG 11
DISCLAIMER ... THIS INFORMATION IS PROVIDED AS GUIDANCE. IT
REQUIRES INTERPRETATION BY HURRICANE SPECIALISTS AND SHOULD
NOT BE CONSIDERED AS A FINAL PRODUCT. PLEASE SEE THE TPC/NHC
OFFICIAL FORECAST.
FORECAST STORM POSITION
HOUR LATITUDE LONGITUDE HEADING/SPEED(KT)
0 14.1 27.0 270./ 8.9
STORM DISSIPATED AT 0 HRS AT THE ABOVE PSN.
maybe this is what it means?
11/0545 UTC 14.4N 27.7W T2.0/2.0 99L
T2.0/2.0 from SSD
For those who are wondering.. with the completely closed low, organized convection and T's up to 2.0
We pretty much have a TD.
hmm will the nhc state this at 5 am or 8 am ?
Looks like Atlantic wants to begin season activity.
Just to help you out there.
NHC would release TD status at 5am or 11am
the 8am is for their potential activity.
Depression?
You said we dont know, 2 days ago all models pull the wave WNW, and only move (2ºN and 7ºW).
My opinion is more west more possible to land in East Coast.
Conditions at CAPL1 as of
(2:06 am CDT)
0706 GMT on 08/11/2009:
Wind Direction (WDIR): SSW ( 210 deg true )
Wind Speed (WSPD): 5.1 kts
Wind Gust (GST): 6.0 kts
Atmospheric Pressure (PRES): 30.07 in
Air Temperature (ATMP): 85.3 °F
Water Temperature (WTMP): 88.7 °F
Sabine Pass, Tx
Air Temperature (ATMP): 82.6 °F
Water Temperature (WTMP): 92.1 °F
Rollover Pass, Tx
Water Temperature (WTMP): 87.1 °
From a few that are still reporting. It's toasty in the NW Gulf. I would hate to see anything get under the right conditions anywhere in the Gulf.
Sure looks like it. With those numbers, no way they don't do it at 5AM. We have our depression.
Not according to what the models ran on but yea, we pretty much have TD 2. Wonder what the NHC will say at 8 AM.
I dont think so.
I more worry about wave at 61W could develop in 24-48hrs.
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