Little change to 90L; new African tropical wave is worth watching

By: Dr. Jeff Masters , 8:53 PM GMT on July 30, 2010

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Invest 90L is a tropical wave in the eastern Atlantic near 10N 33W with a very limited amount of heavy thunderstorm activity but a decent amount of spin. It does not have a well-defined surface circulation, and has shown little change in organization today. CIMMS wind-shear analyses show a low amount of wind shear (5 - 10 knots) over 90L, and sea surface temperatures are a record warm 29°C. The wave currently is in a moist environment and is not being affected by the dry Saharan Air Layer (SAL) to its northwest. The disturbance has moved far enough away from the Equator to leverage the Earth's spin to help it develop. The Saharan Air Layer with its dust and dry air lurks just to the north of 90L, but the SHIPS model predicts 90L will remain far enough from the dry air over the next five days so that it will not interfere with development.


Figure 1. Afternoon visible satellite image from 2pm EDT 7/30/10 of the relatively tiny 90L, and the large new tropical wave that moved off the coast of Africa yesterday.

Forecast for 90L
One factor inhibiting development of 90L this week will be the Madden-Julian Oscillation (MJO.) The MJO currently favors downward motion over the tropical Atlantic, which will act to decrease the chances of tropical storm formation. The Madden-Julian oscillation is a pattern of enhanced rainfall that travels along the Equator from west to east. The pattern has a wet phase with large-scale rising air and enhanced thunderstorm activity, followed by a dry phase with large-scale sinking air and suppressed thunderstorm activity. Each cycle lasts approximately 30 - 60 days. When the Madden-Julian oscillation is in its wet phase over a hurricane-prone region, the chances for tropical storm activity are greatly increased.

Perhaps the main factor interfering with 90L's development will be the presence of the large tropical wave to the east of 90L that moved off the coast of Africa yesterday. This new wave is large enough and close enough to 90L that it will probably begin to dominate regional weather patterns this weekend, stealing away 90L's inflow of low-level moist air. The new wave may also act to bring sinking air over 90L that will tend to suppress 90L's thunderstorm activity. It may turn out that the new wave will also steal some of 90L's spin, and end up being a threat to develop itself later on this weekend.

The latest 8am EDT (12Z) model runs for 90L show very little in the way of development of the storm. The predominant track forecast takes 90L into or just north of the northern Lesser Antilles Islands about 6 - 8 days from now. Looking at climatology based on research done by Dr. Bob Hart at Florida State University,, 90L has a 19% chance of developing into a tropical cyclone by 2pm Sunday. NHC is putting these odds at 20%. Dr. Hart also has an experimental product showing that historically, about 30% of all tropical cyclones that develop at 90L's current position eventually hit land as a hurricane. Of course, 90L is not yet a tropical cyclone, and I think that the large tropical wave off the coast of Africa will kill 90L this weekend.

Tropical wave in the eastern Caribbean
A tropical wave in the eastern Caribbean, south of the Dominican Republic, is moving west at 15 - 20 mph with no signs of development. The wave is under a high 20 knots of wind shear, due to strong upper-level westerly winds from an upper level low centered north of Puerto Rico. This shear is expected to remain remain high through Saturday. By Sunday, when the wave will be approaching Nicaragua, the wave will be far enough away from the upper level low that shear should fall to the moderate range, 10 - 20 knots. Some development is possible on Sunday, but the wave will have only about a 1-day window to develop before its westerly motion brings it inland over Nicaragua on Monday. NHC is giving this wave a 10% chance of developing into a tropical depression by 2pm Sunday.

Extreme cold records for 2010
In my post yesterday, I reported that fourteen countries had set their all-time hottest temperature record this year. I neglected to mention that one country has also set its coldest temperature in recorded history mark in 2010. Guinea had its coldest temperature in its history on January 9, 2010, when the mercury hit 1.4°C (34.5°F) at Mali-ville in the Labe region. Of the 229 countries with extreme coldest temperature records, 14 of these records have occurred in the past ten years (6% of all countries). There have been five times as many (74) extreme hottest temperature records in the past ten years (33% of all countries.) My source for extreme weather records is Chris Burt, author of Extreme Weather.

New study finds huge drop in the plants that form the base of the oceanic food chain
A study published this week in the journal Nature documents that microscopic marine phytoplankton, which form the basis of the marine food chain, have declined by 40% globally since 1950. Joe Romm at climateprogress.org discusses the implications, using this headline:

Scientists may have found the most devastating impact yet of human-caused global warming — a 40% decline in phytoplankton since 1950 linked to the rise in ocean sea surface temperatures. If confirmed, it may represent the single most important finding of the year in climate science.

I plan to discuss this paper next week.

Next update
I'll have an update this weekend, probably by 8pm EDT Saturday.

Jeff Masters

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3 thing too watch

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Quoting brazocane:


And here is a pic from that out of League City




Thanks..is that your home? You in League City? The Houston NWS used to office there and is in Dickinson now..correct?
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Quoting deautschlandfutbol:
hey storm are u still sticking with ya guns on a very active season? i know patience is the key but im really bored haha.


StormW at work
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Quoting StSimonsIslandGAGuy:
Bordonaro it's still not working--maybe a bug on my end.

I am sorry, I will post this, sorry for stretching the blog!!

WFO Monthly/Daily Climate Data


000
CXUS54 KFWD 081624
CF6DFW
PRELIMINARY LOCAL CLIMATOLOGICAL DATA (WS FORM: F-6)

STATION: DALLAS FORT WORTH
MONTH: FEBRUARY
YEAR: 2010
LATITUDE: 32 54 N
LONGITUDE: 97 2 W

TEMPERATURE IN F: :PCPN: SNOW: WIND :SUNSHINE: SKY :PK WND
================================================================================
1 2 3 4 5 6A 6B 7 8 9 10 11 12 13 14 15 16 17 18
12Z AVG MX 2MIN
DY MAX MIN AVG DEP HDD CDD WTR SNW DPTH SPD SPD DIR MIN PSBL S-S WX SPD DR
================================================================================

1 46 29 38 -8 27 0 0.00 0.0 0 5.5 16 190 0 0 9 18 M M
2 51 38 45 -1 20 0 0.00 0.0 0 6.3 14 350 450 70 9 1 17 40
3 47 35 41 -6 24 0 0.14 0.0 0 7.6 16 90 0 0 9 18 24 80
4 44 41 43 -4 22 0 0.23 0.0 0 7.0 15 100 0 0 9 1 21 100
5 59 39 49 2 16 0 0.00 0.0 0 10.3 17 310 350 54 6 1 23 310
6 43 35 39 -8 26 0 0.00 0.0 0 9.2 15 360 129 20 7 18 360
7 44 36 40 -7 25 0 0.05 0.0 0 5.3 13 120 0 0 10 18 15 130
8 42 38 40 -8 25 0 1.06 0.0 0 11.6 25 350 0 0 10 1 30 350
9 43 26 35 -13 30 0 0.00 0.0 0 14.0 29 340 627 96 5 35 350
10 39 29 34 -14 31 0 0.00 0.0 0 3.8 13 30 0 0 10 M M
11 38 32 35 -13 30 0 1.08 11.2 1 5.8 15 180 0 0 10 12 18 190
12 36 29 33 -16 32 0 0.06 1.3 11 5.8 12 260 0 0 10 1 15 290
13 44 32 38 -11 27 0 0.00 0.0 5 8.6 17 180 384 66 6 12 18 180
14 41 29 35 -14 30 0 0.00 0.0 1 11.5 30 10 165 25 5 128 39 10
15 46 29 38 -11 27 0 0.00 0.0 T 14.8 26 310 662 100 0 33 300
16 50 27 39 -11 26 0 0.00 0.0 0 10.8 22 320 616 93 3 26 330
17 54 27 41 -9 24 0 0.00 0.0 0 6.6 12 310 633 95 0 15 320
18 62 32 47 -3 18 0 0.00 0.0 0 7.6 21 160 633 95 1 28 160
19 57 42 50 -1 15 0 0.00 0.0 0 11.6 20 190 84 13 8 23 190
20 62 52 57 6 8 0 0.00 0.0 0 11.5 18 150 221 33 10 24 150
21 65 40 53 2 12 0 0.21 0.0 0 13.0 26 310 61 9 10 1 32 300
22 40 36 38 -13 27 0 0.00 0.0 0 12.5 21 340 0 0 10 25 350
23 42 32 37 -15 28 0 T 0.1 0 13.2 22 20 0 0 10 1 28 30
24 50 29 40 -12 25 0 0.00 0.0 0 7.3 17 340 679 100 1 22 350
25 57 33 45 -7 20 0 T 0.0 0 14.3 26 170 518 76 7 8 36 160
26 50 37 44 -8 21 0 T 0.0 0 13.5 24 360 0 0 9 1 28 360
27 64 34 49 -4 16 0 0.00 0.0 0 5.8 15 300 671 98 2 18 20 320
28 65 38 52 -1 13 0 0.00 0.0 0 8.8 23 150 546 79 7 30 150
================================================================================
SM 1381 956 645 0 2.83 12.6 263.6 7429 193
================================================================================
AV 49.3 34.1 9.4 FASTST 265 40 7 MAX(MPH)
MISC ----> # 30 10 # 39 10
================================================================================
NOTES:
# LAST OF SEVERAL OCCURRENCES

COLUMN 17 PEAK WIND IN M.P.H.

PRELIMINARY LOCAL CLIMATOLOGICAL DATA (WS FORM: F-6) , PAGE 2

STATION: DALLAS FORT WORTH
MONTH: FEBRUARY
YEAR: 2010
LATITUDE: 32 54 N
LONGITUDE: 97 2 W

[TEMPERATURE DATA] [PRECIPITATION DATA] SYMBOLS USED IN COLUMN 16

AVERAGE MONTHLY: 41.7 TOTAL FOR MONTH: 2.83 1 = FOG OR MIST
DPTR FM NORMAL: -7.7 DPTR FM NORMAL: 0.46 2 = FOG REDUCING VISIBILITY
HIGHEST: 65 ON 28,21 GRTST 24HR 1.14 ON 11-12 TO 1/4 MILE OR LESS
LOWEST: 26 ON 9 3 = THUNDER
SNOW, ICE PELLETS, HAIL 4 = ICE PELLETS
TOTAL MONTH: 12.6 INCHES 5 = HAIL
GRTST 24HR 11.2 ON M 6 = FREEZING RAIN OR DRIZZLE
GRTST DEPTH: 11 ON 12 7 = DUSTSTORM OR SANDSTORM:
VSBY 1/2 MILE OR LESS
8 = SMOKE OR HAZE
[NO. OF DAYS WITH] [WEATHER - DAYS WITH] 9 = BLOWING SNOW
X = TORNADO
MAX 32 OR BELOW: 0 0.01 INCH OR MORE: 7
MAX 90 OR ABOVE: 0 0.10 INCH OR MORE: 5
MIN 32 OR BELOW: 13 0.50 INCH OR MORE: 2
MIN 0 OR BELOW: 0 1.00 INCH OR MORE: 2

[HDD (BASE 65) ]
TOTAL THIS MO. 645 CLEAR (SCALE 0-3) 6
DPTR FM NORMAL 197 PTCLDY (SCALE 4-7) 8
TOTAL FM JUL 1 2251 CLOUDY (SCALE 8-10) 14
DPTR FM NORMAL 216

[CDD (BASE 65) ]
TOTAL THIS MO. 0
DPTR FM NORMAL -7 [PRESSURE DATA]
TOTAL FM JAN 1 0 HIGHEST SLP 30.37 ON 10
DPTR FM NORMAL -10 LOWEST SLP 29.70 ON 21

[REMARKS]
EDITED PEAK WIND ON 1ST AND 10TH
#FINAL-02-10#


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Thank you Storm.Very informative.I take your word and seeing all the reports you have given,we are in for a ver active season.
Member Since: June 6, 2010 Posts: 0 Comments: 853
Quoting StSimonsIslandGAGuy:
The 2009-2010 winter was the 18th coldest in our records. That's not exceptional.


Ha, way to smooth it out for the entire CONUS....I said southern and eastern. The northeast got more snow than cold. Take a look at the southern states....top-10 winters for all.
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534. viman
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
312 PM AST FRI JUL 30 2010

.SYNOPSIS...GENERALLY FAIR WEATHER IS EXPECTED ACROSS THE LOCAL
ISLANDS THROUGH THE UPCOMING WEEKEND WITH LIMITED AFTERNOON
CONVECTION EXPECTED TO DEVELOP EACH AFTERNOON OVER THE INTERIOR
AND WESTERN SECTIONS OF PUERTO RICO. INCREASING MOISTURE AND
INSTABILITY ARE EXPECTED BY EARLY NEXT WEEK...WITH AN INCREASE IN
SHOWER ACTIVITY EXPECTED FOR LATE MONDAY AND TUESDAY...AND A
POTENTIALLY STRONG TROPICAL WAVE EXPECTED TO REACH THE LOCAL
ISLANDS BY WEDNESDAY OR THURSDAY.

&&

.DISCUSSION...A TROPICAL WAVE PASSING SOUTH OF THE LOCAL ISLANDS
IS HAVING LITTLE IMPACT ON THE LOCAL WEATHER AS DRIER AIR HAS
ADVECTED ACROSS THE REGION AND A STRONG SUBSIDENCE CAP HAS KEPT
SHOWER ACTIVITY TO A MINIMUM ACROSS THE LOCAL ISLANDS TODAY.
CONTINUED GENERALLY DRY AND FAIR WEATHER IS EXPECTED TO PREVAIL
THROUGH THE UPCOMING WEEKEND...WITH AN ISOLATED SHOWER OR
THUNDERSTORM POSSIBLY BREAKING THROUGH THE CAP ACROSS WESTERN
SECTIONS OF THE ISLAND DURING THE AFTERNOON HOURS EACH DAY.


THE TUTT LOW TO OUR NORTHEAST IS EXPECTED TO RETROGRADE WESTWARD
EARLY NEXT WEEK...WITH A LOW LEVEL TROUGH OR REFLECTION OF THIS
TUTT EXPECTED TO BRING AN INCREASE IN MOISTURE ACROSS THE VI AND
SECTIONS OF PUERTO RICO BY MONDAY AFTERNOON AND TUESDAY. THE MOST
INTERESTING FEATURE OVER THE NEXT SEVEN DAYS IS THE POTENTIALLY
STRONG TROPICAL WAVE...THAT AT THIS TIME HAS A LOW CHANCE OF
DEVELOPING INTO A TROPICAL CYCLONE...EXPECTED TO REACH THE LOCAL
ISLANDS TOWARD THE MIDDLE TO END OF NEXT WEEK. STILL MUCH
UNCERTAINTY...BUT EITHER WAY...EXPECT A SIGNIFICANT INCREASE IN
SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE LOCAL ISLANDS BY NEXT
WEDNESDAY OR THURSDAY AS THIS WAVE APPROACHES THE LOCAL ISLANDS.

&&
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90L RIP
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Quoting StSimonsIslandGAGuy:
The 2009-2010 winter was the 18th coldest in our records. That's not exceptional.


Florida saw real snow not seen since 1977. I think that's pretty darn exceptional to me, considering that was when the PDO was cold. The PDO has just turned cold in June.

http://www.youtube.com/watch?v=CMVJdnG3XKA
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530. jpsb
Quoting Orcasystems:

352. Levi32 11:55 PM GMT on July 30, 2010


Thats a polite way of saying our winter is going to suck isn't it.
Yeah, stock up on fire wood, I am.
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Anyway, I'm not a meterologist, and I am not from the NHC, but I did stay at a Comfort Inn last night and I declare 90L moot at this point.
Member Since: July 11, 2006 Posts: 14 Comments: 11392
hey storm are u still sticking with ya guns on a very active season? i know patience is the key but im really bored haha.
Member Since: June 20, 2010 Posts: 0 Comments: 73
Quoting StSimonsIslandGAGuy:
\


Link not working.

So sorry:
Link
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Quoting Dennis8:


Houston, Texas ( 3rd largest city in USA) had its earliest snowfall on record on December 4, 2009.


And here is a pic from that out of League City


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Gracias My Friend -
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Looks like the ICTZ tonight.
Member Since: July 11, 2006 Posts: 14 Comments: 11392
Sea Ice continues to level off.

http://www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Extent.png

A 6th lowest extent looks likely.
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looks like I need to break out the prozac and sangria,....you boys seriously need something to track!
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And in truth, the past winter was not that bad. Didn't come close to the coldest winter the CONUS has had.


Its all relative to your means. It was a cold winter in the deep south.
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Quoting StSimonsIslandGAGuy:


No that's not all of what I said Levi. That's a dishonest trick of yours to make up something and then claim I said it. I never said one city not breaking a record means that the winter wasn't bad. And you know it.

And in truth, the past winter was not that bad. Didn't come close to the coldest winter the CONUS has had.


A winter that only gets within 17 degrees of the all-time record low is not that extraordinary.

was the part I was addressing.

Also, coldest does not necessarily mean worst. I never said it was the coldest.
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Quoting StSimonsIslandGAGuy:


No that's not all of what I said Levi. That's a dishonest trick of yours to make up something and then claim I said it. I never said one city not breaking a record means that the winter wasn't bad. And you know it.

And in truth, the past winter was not that bad. Didn't come close to the coldest winter the CONUS has had.


Do you like arguing a lot?
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90L not looking too convincing tonight.


wvloop
Member Since: July 11, 2006 Posts: 14 Comments: 11392
Quoting brazocane:


4th


My mistake....trying to move to the HEAD of the class!
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to me the area off the east coast looks like it detacthing it self from the front as the front move out and the frontal cloud area move ne and that area is hold or moving a bit south
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Quoting Bordonaro:

Yes, 14" of wet, heavy snow fell on my neighbors yard in 2-2010. In Arlington, TX.

The temps were between 33-35F for 18 hrs, if temps fell below freezing, I'd hate to think about the total, maybe closer to 18".

Link to 2-2010 DFW, TX Monthy Totals.

Officially -7.7F normal, with 12.6 inches of snow:
Link
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Only 3 models are calling for 90L to become anything.



AOI

AOI

AOI

AOI

AOI

TS BUSTED FORECAST ALIBI
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Quoting StSimonsIslandGAGuy:


No that's not all of what I said Levi. That's a dishonest trick of yours to make up something and then claim I said it. I never said one city not breaking a record means that the winter wasn't bad. And you know it.

And in truth, the past winter was not that bad. Didn't come close to the coldest winter the CONUS has had.


My uncle got a heart attack due to heavy snow. Say that again, that the winter wasn't 'that bad.' >:(
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Storm - You have anything in the C. Pac I need to be aware of?
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Quoting StormW:
Good evening Storm.Could you please post your sypnosis for 90l so I can read it.?I left for work this morning and didnt get to see it.TIA.
Member Since: June 6, 2010 Posts: 0 Comments: 853
Quoting Dennis8:


Houston, Texas ( 3rd largest city in USA) had its earliest snowfall on record on December 4, 2009.


4th
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Hey gang! Been a while since I checked in....it's HOT! It's hotter than hot. I'd wish for a cooling rain, but everytime I do it storms. See the tropics are winding up their gears....here comes August!
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Quoting earthlydragonfly:



I sure wish that were true...


Put it this way.. he has gone away.. I can't see them... therefor he cannot be fed :)

I only unban the loonies when Jeff writes a GW Blog. Then get a coffee... and sit back at watch. When its a weather blog..I just ban them all again... Life is good :)
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Quoting Levi32:


You're saying just because one city didn't break a record means the winter wasn't that bad? Maybe not for you but there were historic snow totals in the eastern US and in the southern US in places like Texas. At one point, the snow map showed nearly uniform snowcover across the entire US east of the great plains all the way down to the north gulf coast. That almost never happens. You mentioned the extreme cold in Florida as well. Ask the people living down there. This was a historic winter and one we will not see again for a long time.


Houston, Texas ( 3rd largest city in USA) had its earliest snowfall on record on December 4, 2009.
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Quoting StSimonsIslandGAGuy:
#481 that's false.



It's accurate in my case.
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Quoting Levi32:


You're saying just because one city didn't break a record means the winter wasn't that bad? Maybe not for you but there were historic snow totals in the eastern US and in the southern US in places like Texas. At one point, the snow map showed nearly uniform snowcover across the entire US east of the great plains all the way down to the north gulf coast. That almost never happens. Ask the people living down there. This was a historic winter and one we will not see again for a long time.

Yes, 14" of wet, heavy snow fell on my neighbors yard in 2-2010. In Arlington, TX.

The temps were between 33-35F for 18 hrs, if temps fell below freezing, I'd hate to think about the total, maybe closer to 18".
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Quoting Orcasystems:


I wouldn't even have known about the statement if you had not quoted it.

Don't feed a troll...and it will go back to where it came from :)



I sure wish that were true...
Member Since: July 1, 2005 Posts: 10 Comments: 1683

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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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