95L growing more organized; Pakistan's Indus River flood peaking downstream

By: Dr. Jeff Masters , 2:23 PM GMT on August 21, 2010

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A tropical wave (Invest 95L) in the far eastern Atlantic about 350 miles southwest of the Cape Verdes Islands has become more organized this morning. Satellite loops show that the wave has some rotation, and heavy thunderstorm activity has increased in recent hours, after a period overnight with little change. Water vapor satellite loops show that there is some dry air to the north of 95L, but this dry air currently appears to be too far away to significantly interfere with development. The main impediment to development is the moderate 10 - 20 knots of wind shear over the system. The shear is forecast to remain in the moderate range through Monday, then decrease. This should allow 95L to develop into a tropical depression Monday or Tuesday. NHC is giving 95L a 30% chance of developing into a tropical depression by Monday morning. With 95L's recent increase in organization, these odds should probably be 50%.


Figure 1. Morning satellite image of 95L.

Forecast for 95L
A ridge of high pressure will force 95L to the west or west-northwest for the next five days, and the system should increase its forward speed from its current 5 - 10 mph to 15 - 20 mph by Monday. A series of two powerful troughs of low pressure are predicted to move off the U.S. East Coast next week and cross the Atlantic; these troughs should be able to pull 95L far enough to the northwest so that it will miss the Lesser Antilles Islands. If 95L stays weak or does not develop in the next five days, as predicted by the NOGAPS model, it has a chance of eventually threatening Bermuda. If 95L develops into a hurricane, as predicted by most of the computer models, it will probably recurve to the east of Bermuda and not threaten any land areas.

Elsewhere in the tropics
The ECMWF model is predicting formation of a tropical depression in the western Gulf of Mexico off the coast of Texas 6 - 7 days from now.

Pakistan's monsoon rains diminish; Indus River flood crest nears the coast
The flooding on Pakistan's largest river, the Indus, has slowly eased along the upper and middle stretches where most of the heavy monsoon rains fell in late July and early August. However, a pulse of flood waters from these heavy rains is headed southwards towards the coast, and flood heights have risen to near all-time record levels today at the Indus River gauge station nearest to the coast, Kotri (Figure 2.) The new flooding has forced the evacuation of an additional 150,000 people in Pakistan today. Flood heights at every monitoring station along the Indus have been the highest or almost the highest since records began in 1947. Fortunately, the monsoon has entered a weak to moderate phase, and heavy rain is not expected over the flood region over the next few days, according to the Pakistan Meteorological Department.


Figure 2. August flow rates along the Indus River, courtesy of the Pakistan Meteorology Department.

Some aid agencies helping with humanitarian crisis in Pakistan:

Doctors Without Borders

The International Red Cross

MERLIN medical relief charity

The mobile giving service mGive allows one to text the word "SWAT" to 50555. The text will result in a $10 donation to the UN Refugee Agency (UNHCR) Pakistan Flood Relief Effort.

Jeff Masters

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Models are starting to split on the long range, which is what I expected earlier today. The GFS does not have it recurving, instead, heads to Bermuda, then north to Canada. It also has a strong ridge over it for quite a while. Remember TD6 form 2004? It was expected to recurve, but the opposite happened. Bermuda needs to monitor this closely, but the East Coast as of now should just "eye" it once in a while for any changes. Models are starting to hint on a stronger ridge, weaker trough, which is why Bermuda needs to pay close attention.
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Quoting atmoaggie:
The change in track forecasts, advisories 1 and 2:

that's a shift of 40 -50 miles further south
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I saw you guys bashing others about comparing this to Hurricane Frances earlier and that makes me angry. Open your eyes: track nearly identical, discussion sounds similar, and long term synoptic pattern is similar. The 18z GFS shows a ballooning ridge any slowdown such as the NHC is referring to in 11 advisory should be seen as a bad thing for eastern seaboard.

I typically don't like to compare storms but this reminds me of Hurricane Frances and the similarities become more evident every with every discussion and every model run
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2030. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15624
Quoting StormW:


Aye!
Weren't you and I talking about that at one time? LOL!


We were indeed. Now its a question of whether the trough picks it up or not.
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Quoting Hurricanes101:
2011. TropicalAnalystwx13 2:45 AM GMT on August 22, 2010

It shifted slightly NE


lol!

Sorry, got the two mixed up!
Member Since: July 6, 2010 Posts: 113 Comments: 31509
NHC shows shear increasing by day 3, which is exactly what the HWRF shows

so don't knock that forecast, a weaker system may just head further west as well
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Quoting StormW:


Don't laugh...it's a known benchmark


Hi Storm

What a difference half a day makes eh ?
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The change in track forecasts, advisories 1 and 2:

Member Since: August 16, 2007 Posts: 6 Comments: 12461
Quoting Surfcropper:
Could be hurricane by Tuesday?


90% chance by Tuesday night IMO
Member Since: July 6, 2010 Posts: 113 Comments: 31509
2018. HadesGodWyvern (Mod)
National Hurricane Center
Tropical Cyclone Advisory #8
TROPICAL DEPRESSION EP082010
3:00 AM UTC August 22 2010
================================

At 3:00 AM UTC, Tropical Depression EIGHT (1005 hPa) located at 21.1N 112.6W or 190 NM southwest of southern tip of Baja California Peninsula has sustained winds of 25 knots with gusts of 35 knots. The depression is reported as moving west northwest at 6 knots.

THIS IS THE FINAL TROPICAL CYCLONE ADVISORY FROM THE NATIONAL HURRICANE CENTER
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Great image earthlydragonfly, tremendous shot. Good night everyone, getting very tired now, talk to you in the morning.
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2011. TropicalAnalystwx13 2:45 AM GMT on August 22, 2010

It shifted slightly NE
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2014. KEEPEROFTHEGATE (Mod)
remember models are meant to be used for guidance purposes only and donot depict final outcome in any single one event
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Quoting DestinJeff:
looks to have shifted right of previous advisory


Left...Look at the very end point.
Member Since: July 6, 2010 Posts: 113 Comments: 31509
Quoting DestinJeff:
looks to have shifted right of previous advisory
No more shifts please.A few shifts,and we could be talking about a Fabian.
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000
WTNT41 KNHC 220243
TCDAT1
TROPICAL DEPRESSION SIX DISCUSSION NUMBER 2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010
1100 PM AST SAT AUG 21 2010

CONVENTIONAL SATELLITE AND A 2202 UTC SSMIS MICROWAVE OVERPASS SHOW
IMPROVED CURVED BANDING...PARTICULARLY OVER THE WESTERN PORTION OF
THE CYCLONE. ALTHOUGH DEEP CONVECTION REMAINS A BIT LIMITED OVER
THE EASTERN SEMI-CIRCLE...A 2300 UTC ASCAT PASS INDICATED A MORE
SYMMETRIC CIRCULATION THAN EARLIER NOTED...AND BELIEVABLE 25 KT
WINDS OVER THE SOUTHEAST QUADRANT. OUTFLOW OVER THE NORTHWESTERN
AREA OF THE SYSTEM APPEARS TO BE IMPROVING AND HAS BECOME MORE
DIFFLUENT. SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE 2.0
AND 1.5 RESPECTIVELY. BASED ON THE PREMISE THAT THE WINDS ARE
PROBABLY A LITTLE STRONGER IN THE CONVECTIVE BANDING TO THE WEST
AND NORTHWEST OF THE CENTER...THE INITIAL INTENSITY IS ADJUSTED UP
TO 30 KT.

THE CYCLONE SHOULD GRADUALLY STRENGTHEN AS IT REMAINS OVER WARM SEA
SURFACE TEMPERATURES AND WITHIN A RELATIVELY LOW NORTHEASTERLY
SHEAR ENVIRONMENT DURING...AT LEAST FOR THE NEXT 3 DAYS. THE SHIPS
AND THE GFDL CONTINUE TO INDICATE THAT THE SYSTEM WILL BECOME A
HURRICANE WITHIN 3 DAYS...AND THIS IS ALSO INDICATED IN THE
OFFICIAL FORECAST. THROUGH THE REMAINING PERIOD...INCREASING
SOUTHWESTERLY SHEAR IS EXPECTED OVER THE TRACK IN RESPONSE TO A MID
TO UPPER TROUGH MOVING OFF OF THE EASTERN SEABOARD AROUND DAY 5.
SUBSEQUENTLY...THE INTENSITY FORECAST INDICATES ONLY MODEST
STRENGTHENING DURING THIS TIME-FRAME.

THE SYSTEM HAS BEEN MOVING WEST-NORTHWESTWARD...OR...290/7. THE DEEP
TRADES ASSOCIATED WITH THE SUBTROPICAL RIDGE TO THE NORTH OF THE
DEPRESSION NOW APPEAR TO BE THE MORE DOMINANT STEERING
MECHANISM...WITH LESS OF AN INFLUENCE FROM THE SOUTHWESTERLY
MONSOONAL FLOW. DYNAMICAL MODELS ARE IN GOOD AGREEMENT WITH THE
RIDGE STEERING THE CYCLONE IN A WEST-NORTHWESTWARD MOTION THROUGH
DAY 3. AFTERWARD...A TURN TOWARD THE NORTHWEST IS INDICATED IN THE
OFFICIAL FORECAST AS A DEEP-LAYER MID-LATITUDE TROUGH MOVES OVER
THE CENTRAL ATLANTIC AND BREAKS DOWN THE WESTERN PERIPHERY OF THE
RIDGE. THE NHC TRACK FORECAST IS A LITTLE SLOWER THAN THE PREVIOUS
ADVISORY...AND IS BASED ON THE MULTI-MODEL CONSENSUS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 22/0300Z 11.3N 32.6W 30 KT
12HR VT 22/1200Z 12.0N 33.9W 35 KT
24HR VT 23/0000Z 12.9N 36.0W 40 KT
36HR VT 23/1200Z 13.8N 38.4W 50 KT
48HR VT 24/0000Z 14.7N 41.3W 60 KT
72HR VT 25/0000Z 18.0N 47.0W 80 KT
96HR VT 26/0000Z 21.5N 51.5W 90 KT
120HR VT 27/0000Z 25.0N 55.0W 95 KT

$$
FORECASTER ROBERTS/BEVEN
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2008. angiest
Quoting Hurricanes101:
now I see a slight WNW movement

between W and WNW really


And yet NHC now says 290 degrees.
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Quoting clwstmchasr:
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 8 MPH...

Any questions??????


Yes, which came first, the chicken or the egg?

I see TD6's up to 35 mph now.
Member Since: July 8, 2005 Posts: 259 Comments: 23599
Quoting clwstmchasr:
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 8 MPH...

Any questions??????


yea why you got to have an attitude?
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2004. HadesGodWyvern (Mod)
National Hurricane Center
Tropical Cyclone Advisory #2
TROPICAL DEPRESSION EP092010
3:00 AM UTC August 22 2010
================================

At 3:00 AM UTC, Tropical Depression NINE (1006 hPa) located at 13.8N 93.8W or 165 NM south southeast of Salina Cruz, Mexico has sustained winds of 30 knots with gusts of 40 knots. The depression is reported as moving west at 3 knots.

Forecast and Intensity
=========================
24 HRS: 13.8N 95.6W - 45 knots (Tropical Cyclone)

Tropical Cyclone Watch
======================
A Tropical Storm Watch is in effect for the Mexico coast from Salina Cruz westward to Lagunas de Chacahua
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Quoting earthlydragonfly:



After reading some comments I had to go back a few hundred to find it. Well worth it! Great Picture. You are talented!
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Quoting earthlydragonfly:

WOW! That's a great shot. Post 1772
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11:00 PM AST Sat Aug 21
Location: 11.3°N 32.6°W
Max sustained: 35 mph
Moving: WNW at 8 mph
Min pressure: 1008 mb
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting angiest:


I must say, LBAR is most interesting.
Danielle better have 4 wheel discs on her to navigate that turn.
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:)
Member Since: July 6, 2010 Posts: 113 Comments: 31509
Quoting clwstmchasr:


Which models show it going west?


The reason the HWRF is west is because it weakens Danielle considerably to a tropical storm in 126 hours. BAM Shallow (BAMS) and BAM Mid (BAMM) is a little west because theses models only focus the steering of the storm in the lower levels of the atmosphere. If Danielle develops to her potential, it will follow the weakness between the highs. There is no where else to go - again path of least resistance.
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Member Since: July 25, 2008 Posts: 0 Comments: 596
1994. JRRP
11.4n
33w
imo
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About to mention the 18z GFS, others would probably say its just the 18z GFS, but it is a model run which tries to predict the future.
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Winds at 35mph.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
11PM EDT CONE:

Member Since: September 2, 2009 Posts: 130 Comments: 21091
1986. RMCF
Quoting atmoaggie:
? Their track at 17 UTC yesterday didn't call for 15 N until after 19 UTC today.

GFS at one point had the storm coming off africa at 15n about a week ago you love identifying problems.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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