Felicia not weakening; new African wave may develop
Hurricane Felicia has not weakened today, and continues to hold its own in spite of cool sea surface temperatures beneath it. Recent satellite imagery shows that the tops of thunderstorms surrounding the eye have cooled slightly, indicating that the updrafts sustaining the eyewall are maintaining their strength. The appearance of the hurricane has improved some today, with the storm assuming a more symmetric appearance.
Figure 1. Current satellite image of Hurricane Felicia.
Sea surface temperatures (SSTs) under Felicia have now fallen to 24.7°C, well below the 26°C threshold typically needed to sustain a hurricane. SSTs will slowly increase to 26°C by the time the storm reaches Hawaii, though. Wind shear is expected to remain low to moderate, 5 - 15 knots, through Monday morning. By Monday night, shear will rise to 20 knots, and remain above 20 knots thereafter. The higher shear combined with the relatively cool SSTs should mean that Felicia will be rapidly weakening in its final 24 hours before reaching Hawaii. Several of the computer models continue to show that this shear will be high enough to tear Felicia apart before it reaches Hawaii, though it appears to me that Felicia's current strength and annular structure will help it resist the shear enough to allow the storm to hit Hawaii as a tropical depression with 35 mph winds. Regardless, Felicia will bring heavy rain Hawaii beginning on Monday morning, and these rains will have the capability of causing flash floods and mudslides. The Hurricane Hunters are scheduled to make their first low-level investigation of Felicia this afternoon (around 10 am Hawaiian time). The NOAA jet also flies into Felicia today, and will drop a series of dropsondes that will be used to gather data that will be fed into today's 12Z and 00Z computer model runs.
Typhoon Morakot hits Taiwan
Typhoon Morakot hit Taiwan yesterday, battering the island with Category 1 winds and heavy rain. The Taipei airport recorded sustained winds of 56 mph, gusting to 76 mph, at the peak of the storm. Morakot killed 6 on Taiwan and 10 in the Philippines, and is headed towards a final landfall on mainland China as a tropical storm later today. Storm chaser James Reynolds intercepted the storm and posted videos on typhoonfury.com and Youtube. Morakot is still visible today on Taiwan radar.
Figure 2. Visible satellite image of a spinning tropical wave leaving the coast of Africa. The image was taken at 8am EDT 8/8/09.
African tropical wave may develop
A strong tropical wave with a moderate amount of spin is moving off the coast of Africa this morning. The wave is under about 10 - 20 knots of wind shear and has sea surface temperatures beneath it of 27°C. These conditions are probably too marginal to allow development over the next two days. As the wave moves westward away from Africa over the next few days, wind shear should slowly decrease and the SSTs will warm, potentially allowing for some slow development. The UKMET, GFS, and NOGAPS models all indicate the possibility that this will become a tropical depression 3 - 5 days from now. The ECMWF model forecasts that strong easterly winds over the wave will create too much shear to allow development. The wave is well south of the Saharan Air Layer, so dry air and African dust should not interfere over the next 3 - 5 days. I give the wave a medium (30 - 50% chance) of developing into a tropical depression in the next seven days.
I'll have an update on Sunday.
Jeff Masters
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WAVETRAK - Tropical Wave Tracking
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By the way remember this is a real diagram i am not Jasonisacoolman09.
A TROPICAL WAVE HAS BEEN ADDED TO THE SURFACE ANALYSIS AT
08/1200 UTC OVER THE FAR E ATLC. THIS TROPICAL WAVE IS ALONG
15W/16W S OF 16N MOVING W 10-15 KT. RECENT VISIBLE SATELLITE
IMAGERY INDICATES A WELL-DEFINED LOW/MID-LEVEL CYCLONIC
CIRCULATION CENTER ASSOCIATED WITH THIS WAVE NEAR 11N16W.
TIME-HEIGHT ANALYSES FROM BAMAKO IN MALI INDICATE THAT THE
DIRECTION OF THE FLOW BELOW 550 MB SHIFTED FROM NORTHEASTERLY TO
SOUTHEASTERLY BETWEEN 07/1200 UTC AND 07/1800 UTC...SUGGESTING
WAVE PASSAGE AT BAMAKO DURING THIS TIME. SUNY ALBANY GFS
ANALYSES DEPICT THE LOW-LEVEL VORTICITY MAXIMUM ASSOCIATED WITH
THIS WAVE TRACKING WESTWARD ACROSS WEST CENTRAL AFRICA DURING
THE LAST FEW DAYS. THE 5-DAY HOVMOLLER DIAGRAM FOR SATELLITE
IMAGERY ALSO INDICATES AN AREA OF ENHANCED CLOUDINESS ASSOCIATED
WITH THE WAVE TRACKING WESTWARD ACROSS WEST CENTRAL AFRICA
DURING THE LAST FEW DAYS. A BAND OF NUMEROUS MODERATE/ISOLATED
STRONG CONVECTION ASSOCIATED WITH THIS WAVE IS WITHIN 90 NM
EITHER SIDE OF A LINE FROM 11N15W TO 10N17W TO 10N21W.
Is that Steve Lyons?
Very detailed analysis and it's nice to see they use Suny Albany
Naval Research Lab/ NPOESS
Vorticity has increased substantially on both waves since yesterday. This will be an interesting week.
Latest run: 12Z UKMET
A TROPICAL WAVE HAS BEEN ADDED TO THE SURFACE ANALYSIS AT
08/1200 UTC OVER THE FAR E ATLC. THIS TROPICAL WAVE IS ALONG
15W/16W S OF 16N MOVING W 10-15 KT. RECENT VISIBLE SATELLITE
IMAGERY INDICATES A WELL-DEFINED LOW/MID-LEVEL CYCLONIC
CIRCULATION CENTER ASSOCIATED WITH THIS WAVE NEAR 11N16W.
TIME-HEIGHT ANALYSES FROM BAMAKO IN MALI INDICATE THAT THE
DIRECTION OF THE FLOW BELOW 550 MB SHIFTED FROM NORTHEASTERLY TO
SOUTHEASTERLY BETWEEN 07/1200 UTC AND 07/1800 UTC...SUGGESTING
WAVE PASSAGE AT BAMAKO DURING THIS TIME. SUNY ALBANY GFS
ANALYSES DEPICT THE LOW-LEVEL VORTICITY MAXIMUM ASSOCIATED WITH
THIS WAVE TRACKING WESTWARD ACROSS WEST CENTRAL AFRICA DURING
THE LAST FEW DAYS. THE 5-DAY HOVMOLLER DIAGRAM FOR SATELLITE
IMAGERY ALSO INDICATES AN AREA OF ENHANCED CLOUDINESS ASSOCIATED
WITH THE WAVE TRACKING WESTWARD ACROSS WEST CENTRAL AFRICA
DURING THE LAST FEW DAYS. A BAND OF NUMEROUS MODERATE/ISOLATED
STRONG CONVECTION ASSOCIATED WITH THIS WAVE IS WITHIN 90 NM
EITHER SIDE OF A LINE FROM 11N15W TO 10N17W TO 10N21W.
The Se La. and S. Miss Vorticity matches well with the GOM Sat presentation.
...ah....wrong...again...reality isn't reality until it's real...
Afternoon Press! How's the weather in the Carolinas?
:)
NHC/TPC, always on the watch.
...I give up...
Looks like Avila
The ECMWF will:
A. Show development
B. Not show development
*Polls close in an hour
The tropics or blog?
Same here in Florida. Good thing though at the end of the month they get that shuttle up at 1 AM on the 23rd out of the Cape. They won't have to scrub like 5 times.
ABNT20 KNHC 081734
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT SAT AUG 8 2009
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.
$$
FORECASTER BLAKE/BRENNAN
B.
B
08/1200 UTC OVER THE FAR E ATLC. THIS TROPICAL WAVE IS ALONG
15W/16W S OF 16N MOVING W 10-15 KT. RECENT VISIBLE SATELLITE
IMAGERY INDICATES A WELL-DEFINED LOW/MID-LEVEL CYCLONIC
CIRCULATION CENTER ASSOCIATED WITH THIS WAVE NEAR 11N16W.
TIME-HEIGHT ANALYSES FROM BAMAKO IN MALI INDICATE THAT THE
DIRECTION OF THE FLOW BELOW 550 MB SHIFTED FROM NORTHEASTERLY TO
SOUTHEASTERLY BETWEEN 07/1200 UTC AND 07/1800 UTC...SUGGESTING
WAVE PASSAGE AT BAMAKO DURING THIS TIME. SUNY ALBANY GFS
ANALYSES DEPICT THE LOW-LEVEL VORTICITY MAXIMUM ASSOCIATED WITH
THIS WAVE TRACKING WESTWARD ACROSS WEST CENTRAL AFRICA DURING
THE LAST FEW DAYS. THE 5-DAY HOVMOLLER DIAGRAM FOR SATELLITE
IMAGERY ALSO INDICATES AN AREA OF ENHANCED CLOUDINESS ASSOCIATED
WITH THE WAVE TRACKING WESTWARD ACROSS WEST CENTRAL AFRICA
DURING THE LAST FEW DAYS. A BAND OF NUMEROUS MODERATE/ISOLATED
STRONG CONVECTION ASSOCIATED WITH THIS WAVE IS WITHIN 90 NM
EITHER SIDE OF A LINE FROM 11N15W TO 10N17W TO 10N21W.
If it keeps up we'll probably see a mention at 8 PM.
Tropics
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