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.
Reader Comments
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 — Blog Index
Quite.
Quoting TampaSpin:
We need to keep a close eye on the little thing at 59W. Its really looking very impressive........someone one asked can a storm begin to form without any Model support......this might be a good example!
FROM NOTHING IT COMES
I know its nearing the dead zone.....but, it has very good conditions currently....Shear is under 20kts which is unusual there and the environment is fairly moist....this could be a rapid developer and catch alot by surprise....
Good Vorticity at 850mb
Divergence was nothing now look....
Convergence was nothing also earlier....HUM
WS gets there early to hurricane proof his dorm room.
Hi Futuremet, I am thinking, though many will think me crazy, that the Barbados blob (cool name), may just be Ana...
Lol.
freshman dorms are in a trashcan isn't it?
000
ABNT20 KNHC 101736
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT MON AUG 10 2009
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
SHOWERS AND THUNDERSTORMS HAVE CONTINUED TO DIMINISH IN ASSOCIATION
WITH THE BROAD AREA OF LOW PRESSURE LOCATED JUST TO THE WEST-
SOUTHWEST OF THE SOUTHERN CAPE VERDE ISLANDS. HOWEVER...CONDITIONS
STILL APPEAR FAVORABLE FOR DEVELOPMENT OF THIS SYSTEM...AND IT
COULD BECOME A TROPICAL DEPRESSION DURING THE NEXT COUPLE OF DAYS
AS IT MOVES TOWARD THE WEST AT 10 TO 15 MPH. THERE IS A MEDIUM
CHANCE...30 TO 50 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS.
A SMALL AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS
PRODUCING SHOWERS AND THUNDERSTORMS NEAR THE WINDWARD ISLANDS.
DEVELOPMENT OF THIS SYSTEM...IF ANY...IS EXPECTED TO BE SLOW TO
OCCUR AS IT MOVES WESTWARD AT 10 TO 15 MPH. LOCALLY HEAVY RAIN AND
GUSTY WINDS WILL CONTINUE TO SPREAD OVER PORTIONS OF THE WINDWARD
ISLANDS THROUGH TUESDAY MORNING. THERE IS A LOW CHANCE...LESS THAN
30 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
$$
FORECASTER BERG
That looks like a definite loop in the mid-gulf with Category 5 potential....NOLA got lucky last year as Gustav was positioned perfectly to take the city underwater again. With the current set up a hurricane hitting Morgan City or a bit East will put a lot of the city back underwater.
The Industrial Canal barely held last time...
Doesn't mean it isn't a threat to other people. Selfish much?
'Tis. I remember early in the season last year, when a similar system came through, lots of rain etc, within a few days it was a storm into the Caribbean Sea.
This system is stronger that that one was. It has suddenly blown up since early this am.
Tremendous. Up to now there was no wind with it, but now I see evidence of wind pickup.
I am telling you, it might seem a longshot, but it is worth considering, that this is the season's first on its way.
What is noticeable about the convergence and divergence of the Antilles is the fact that they are well stacked. If the divergence was elongated, this would indicate that the most of the convection was a result of upper level diffluence, which was the case over the past few days as a anticyclone was located over the region when the TUTT was lifting. Persistent low level convergence can also indicate the formation of some sort of surface low.
Orange and 9E
We learned for Andrew....it was chaos getting out of Lafayette...so we stayed. The local school board didn't shut schools down until noon the day before it hit.
Good point
ABNT20 KNHC 101736
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT MON AUG 10 2009
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
SHOWERS AND THUNDERSTORMS HAVE CONTINUED TO DIMINISH IN ASSOCIATION
WITH THE BROAD AREA OF LOW PRESSURE LOCATED JUST TO THE WEST-
SOUTHWEST OF THE SOUTHERN CAPE VERDE ISLANDS. HOWEVER...CONDITIONS
STILL APPEAR FAVORABLE FOR DEVELOPMENT OF THIS SYSTEM...AND IT
COULD BECOME A TROPICAL DEPRESSION DURING THE NEXT COUPLE OF DAYS
AS IT MOVES TOWARD THE WEST AT 10 TO 15 MPH. THERE IS A MEDIUM
CHANCE...30 TO 50 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS.
A SMALL AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS
PRODUCING SHOWERS AND THUNDERSTORMS NEAR THE WINDWARD ISLANDS.
DEVELOPMENT OF THIS SYSTEM...IF ANY...IS EXPECTED TO BE SLOW TO
OCCUR AS IT MOVES WESTWARD AT 10 TO 15 MPH. LOCALLY HEAVY RAIN AND
GUSTY WINDS WILL CONTINUE TO SPREAD OVER PORTIONS OF THE WINDWARD
ISLANDS THROUGH TUESDAY MORNING. THERE IS A LOW CHANCE...LESS THAN
30 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
$$
FORECASTER BERG
Perhaps...perhaps....
I thought this wave diminishing completely yesterday.
The convection and organization has been on a steady upward tick all day. I would not be surprised to see this area continue to improve. The real test will be to see how it fares during the afternoon heat.
Those are some really nice observations. This disturbance will be very interesting to watch. Now that the NHC is monitoring the system, we could very well see Invest 90L.
might be 90l soon before the new wave off of africa would we all laugh if the 60 waves becomes anna first ahahahah
Viewing: 401 - 451
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 — Blog Index