Ernesto weakens; Florence forms; fires, historic heat wave in Oklahoma

By: Dr. Jeff Masters , 4:12 PM GMT on August 04, 2012

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Enigmatic Tropical Storm Ernesto continues westward across the Caribbean, but has weakened. Ernesto certainly looks impressive on visible satellite loops, with a symmetric shape, good spiral banding, and an upper-level outflow channel to the north and east. But this morning's flight by the Hurricane Hunters found that Ernesto had weakened, with top winds of just 50 mph, and a central pressure that had risen to 1008 mb. The storm is fighting low to moderate wind shear of 5 - 15 knots, and water vapor satellite loops show a large area of dry air to the west. Upper level winds from the west are driving this dry air into the west side of the storm. Ernesto's rains are staying just north of the ABC Islands, as seen on Aruba radar. The southern shore of the Dominican Republic is experiencing occasional heavy rains from Ernesto's spiral bands.


Figure 1. Morning visible satellite image of Ernesto taken at 8 am EDT, with echoes from a microwave satellite instrument in the 85 GHz band superimposed. Image credit: Navy Research Lab, Monterey.

Forecast for Ernesto
Ernesto continues to be a major challenge to forecast. Despite the seemingly favorable conditions for intensification expected today through Tuesday, with low wind shear, a moister environment, and increasing heat energy in the ocean, many of our top computer models refuse to predict intensification, and in fact, weaken the storm. Of the major dynamical models NHC uses operationally--the ECMWF, GFS, NOGAPS, UKMET, GFDL, and HWRF--only the NOGAPS and GFDL show Ernesto reaching hurricane strength in the Caribbean. The ECMWF dissipates the storm. However, some of the best statistical models, such as the LGEM and SHIPS, do show Ernesto becoming a Category 1 or 2 hurricane in the Caribbean. The official NHC intensity forecast of a Category 1 hurricane between Jamaica and Mexico's Yucatan Peninsula is a reasonable compromise, but the uncertainty in this is high. It would not be a surprise to see Ernesto mysteriously degrade, or undergo rapid intensification into a Category 2 hurricane off the coast of the Yucatan. Such is the state of modern hurricane intensity forecasting. Given that we don't have a very good idea of how strong Ernesto will become, making an accurate track forecast is hard. A stronger Ernesto will be more likely to feel the influence of a trough of low pressure moving to the north of the storm on Tuesday, which would pull the storm to the northwest into the Gulf of Mexico. This would likely result in a landfall in the U.S. A weaker Ernesto is more likely to head almost due west, resulting in a landfall Wednesday in Belize or Mexico's Yucatan Peninsula. This is the more likely solution, given the recent behavior of the storm.

Tropical Storm Florence forms
Tropical Storm Florence has arrived in the far Eastern Atlantic, marking the 3rd earliest date for formation of the Atlantic's sixth named storm. Only 2005 and 1936 had earlier arrivals of the season's sixth storm. The new tropical storm developed unusually quickly from a tropical wave that moved off the coast of Africa just two days ago, and the storm's formation was aided by a pulse warm ocean water and associated low pressure called a Convectively Coupled Kelvin Wave (CCKW.) The SHIPS model is diagnosing a moderate 10 - 15 knots of wind shear over Florence, and predicts that the shear will stay in the moderate range over weekend, then increase to the high range as Florence encounters an upper-level trough of low pressure. The latest Saharan Air Layer Analysis shows that a large area of dry air lies to the north and west of Florence, and this dry air will likely cause problems for the storm. Ocean temperature are near 26 - 26.5°C, which is right at the threshold for where a tropical storm can typically exist. The predicted steering current flow for Florence does not favor a long-range threat to any land areas.

Historic heat wave in Oklahoma
A historic heat wave and drought fueled raging fires on Friday in Oklahoma. The fires destroyed at least 65 homes, forced multiple evacuations, and closed major roads. Oklahoma City had its hottest day in history, hitting 113°, tying the city's all-time heat record set on August 11, 1936. The low bottomed out at 84°, the warmest low temperature ever recorded in the city (previous record: a low of 83° on August 13, 1936.) Oklahoma City has now had three consecutive days with a high of 112° or higher, which has never occurred since record keeping began in 1891. With today's high expected to reach 113° again, the streak may extend to four straight days. Yesterday was the third consecutive day with more than a third of Oklahoma experiencing temperatures of 110° or higher, according to readings from the Oklahoma Mesonet. NOAA's Storm Prediction Center (SPC) declared a "Critical" fire weather day over most of Oklahoma yesterday, due to extreme heat and drought, low humidities, and strong winds. Between 4 - 5 pm CDT Friday, Oklahoma City had a temperature of 113°, a humidity of 12%, and winds of 14 mph gusting to 25 mph. Another "Critical" fire weather day has been declared for Saturday. A cold front approaching from the northwest will bring winds even stronger than Friday's winds, and Oklahoma will likely endure another hellish day of extreme heat, dryness, and fires.


Figure 2. The Geary, Oklahoma fire, looking north, on August, 3, 2012. Image credit: Oklahoma City Fire Department. The Geary fire spawned a gustnado.

Only comparable heat wave: August 1936
The only heat wave in Oklahoma history that compares to this week's occurred in the great Dust Bowl summer of 1936, the hottest summer in U.S. history. Oklahoma City experienced three days at 110° that summer, and a record streak of 22 straight days with a temperature of 100° or hotter. Those numbers are comparable to 2012's: three days at 110° or hotter, and a string of 17 consecutive days with temperatures of 100° or hotter. It's worth noting that Oklahoma City has experienced only 11 days since 1890 with a high of 110° or greater. Three of those days were in 2011, three were in 2012, and three were in the great Dust Bowl summer of 1936. Clouds moved in over Tulsa, Oklahoma yesterday, holding down the high temperature to just 107°, ending that city's 3-day streak of 110°+ days. The only longer streak was 5 consecutive days on August 9 - 13, 1936.


Figure 3. Most of Oklahoma has experienced eight consecutive days with highs of 100° or more, and many regions, including Oklahoma City, have had a streak of 17 such days. Image credit: Oklahoma Mesonet.

Jeff Masters

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About the trade wind thing, NOT BUYING IT. If your telling me the pros don't have a clue then go apply for a job there, just stop the misinformation.

IT IS ALSO UNCLEAR WHY ERNESTO HAS LOST ORGANIZATION SINCE THE OUTFLOW IS GOOD IN ALL DIRECTIONS...THE VERTICAL WIND SHEAR IS LIGHT...AND THE SEA SURFACE TEMPERATURES ARE WARM. ONE POSSIBLE CAUSE MIGHT BE DRY AIR SEEN IN WATER VAPOR IMAGERY WEST OF THE CYCLONE.
Member Since: Posts: Comments:
TROPICAL STORM FLORENCE DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062012
1100 PM AST SAT AUG 04 2012

FLORENCE IS BECOMING BETTER ORGANIZED. BANDING FEATURES ASSOCIATED
WITH THE CYCLONE HAVE RECENTLY DISSIPATED IN FAVOR OF A CENTRAL
DENSE OVERCAST. EARLIER TRMM AND WINDSAT OVERPASSES REVEAL A WELL-
DEFINED LOW-LEVEL STRUCTURE UNDERNEATH THIS NEW CONVECTIVE MASS...
WITH A NEARLY CLOSED RING OF CONVECTION NOW PRESENT. A DVORAK
INTENSITY ESTIMATE OF 3.5/55 KT FROM TAFB AT 0000 UTC AND THREE-
HOURLY AVERAGED ADT VALUES OF AROUND 3.3 ARE THE BASIS FOR
INCREASING THE INITIAL INTENSITY TO 50 KT FOR THIS ADVISORY.

THE INTENSITY FORECAST IS TRICKY. DESPITE BEING IN A LOW-SHEAR
ENVIRONMENT...FLORENCE IS FORECAST TO MOVE THROUGH A TONGUE OF
MARGINALLY WARM WATERS OVER THE NEXT COUPLE OF DAYS. IN ADDITION...
EUMETSAT RGB SATELLITE IMAGERY INDICATES THAT THE CYCLONE IS
SURROUNDED BY A RATHER DRY AIR MASS...AND THIS AIR MASS SHOULD
ACCOMPANY FLORENCE ON ITS WESTWARD TREK. THESE NEGATIVE FACTORS
SUGGEST THAT ANY STRENGTHENING IN THE SHORT TERM WOULD NOT LIKELY
BE SIGNIFICANT. BEYOND 72 HOURS...GLOBAL MODELS SHOW FLORENCE
ENCOUNTERING INCREASING SOUTHWESTERLY SHEAR ASSOCIATED WITH AN
UPPER-LEVEL TROUGH OVER THE CENTRAL ATLANTIC. EVEN THOUGH THE
STORM WILL BE MOVING OVER WARMER WATERS BY THIS TIME...THE SHEAR
SHOULD BE STRONG ENOUGH TO INDUCE WEAKENING. THE NEW NHC INTENSITY
FORECAST IS ADJUSTED UPWARD THROUGH 48 HOURS BASED ON
CURRENT TRENDS AND IS ABOUT THE SAME AS THE PREVIOUS FORECAST AFTER
THAT TIME. THE FORECAST IS IN EXCELLENT AGREEMENT WITH THE LATEST
SHIPS/LGEM OUTPUT.

THE INITIAL MOTION ESTIMATE IS 295/13. A MID-LEVEL RIDGE OVER THE
EASTERN ATLANTIC IS EXPECTED TO BUILD WESTWARD DURING THE NEXT
SEVERAL DAYS...WHICH WILL CAUSE THE TRACK OF FLORENCE TO BEND TOWARD
THE WEST. LATE IN THE FORECAST PERIOD...THE CYCLONE IS EXPECTED TO
ENCOUNTER A WEAKNESS IN THE SUBTROPICAL RIDGE OVER THE CENTRAL
ATLANTIC WHICH SHOULD INDUCE A WEST-NORTHWESTERLY HEADING. ALTHOUGH
THE SPREAD IN THE TRACK GUIDANCE HAS DECREASED THIS CYCLE...IT
REMAINS FAIRLY SIGNIFICANT BEYOND 72 HOURS. THE DIFFERENCE IN TRACK
SOLUTIONS AT LATER TIMES APPEARS DEPENDENT ON THE VERTICAL DEPTH/
STRENGTH OF THE CYCLONE...WITH THE ECMWF/GFDL/HWRF FORECASTING A
WEAKER VERSION OF FLORENCE AND THE GFS FAVORING A STRONGER SYSTEM.
THE NEW NHC FORECAST TRACK REMAINS IN BETWEEN THESE TWO EXTREMES
BUT HAS BEEN ADJUSTED TOWARD THE CAMP OF MODELS FAVORING A WEAKER
CYCLONE GIVEN THE SHEAR FORECAST.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0300Z 16.1N 33.0W 50 KT 60 MPH
12H 05/1200Z 16.5N 34.8W 55 KT 65 MPH
24H 06/0000Z 17.0N 37.2W 60 KT 70 MPH
36H 06/1200Z 17.5N 39.7W 60 KT 70 MPH
48H 07/0000Z 18.1N 42.6W 60 KT 70 MPH
72H 08/0000Z 19.3N 49.0W 45 KT 50 MPH
96H 09/0000Z 20.9N 55.1W 35 KT 40 MPH
120H 10/0000Z 23.5N 60.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
Member Since: May 21, 2006 Posts: 5092 Comments: 115713
Quoting all4hurricanes:
I have to say this is the most confusing storm since Fay, except it's bag of tricks seem to backfire. Florence has been steadily strengthening I think she might become a hurricane.

Debby?
Member Since: July 6, 2010 Posts: 113 Comments: 33621
Quoting ilovehurricanes13:
HURRICANE HUNTER AIRCRAFT REPORTS ERNESTO HAS LOST SOME ORGANIZATION
11:00 PM EDT Sat Aug 4
Location: 15.4°N 72.7°W
Moving: WNW at 22 mph
Min pressure: 1007 mb
Max sustained: 60 mph


i was right again!!


Poof
Member Since: Posts: Comments:
Quoting Levi32:


Oh it's open. Not a single westerly reading from recon yet during the entire mission. NHC won't just discontinue advisories though. They do this a lot when a system is expected to easily regenerate a closed circulation in the near future.





They still think dry air is the reason for the COC breakdown today *rolleyes*


Like I said, you should work there IMO.

Then I can read "FORECASTER: LEVI" and be more confident.


So what's your thought on RI flag.


Oh also: K.O.T.G we are west of 71W now.
Member Since: June 24, 2012 Posts: 0 Comments: 1546
I have to say this is the most confusing storm since Fay, except it's bag of tricks seem to backfire. Florence has been steadily strengthening I think she might become a hurricane.
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Quoting weathermanwannabe:
Some people don't listen (or read)....


Good evenin folks
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2588. scott39
Quoting scott39:
15.3N 71.7W
Hmm close
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Quoting NCHurricane2009:

I don't know...tryin to figure this out from the info being posted. The 11 PM EDT discussion from NHC will tell us the official word....


Probably got Avila et el confused,perhaps the HH data will help them figure out exactly going on. Or perhaps someone in here? Can it be as simple as moving too fast and dry air?
Member Since: September 18, 2010 Posts: 0 Comments: 5296
Member Since: Posts: Comments:
Quoting ProgressivePulse:
...HURRICANE HUNTER AIRCRAFT REPORTS ERNESTO HAS LOST SOME ORGANIZATION...

But he has also gained some good organization in the reloc... I expect him to start behaving like a normal TS from here one.
Member Since: Posts: Comments:
Good call Dr. M. You've been saying exactly this for the past few days.

IT IS ALSO UNCLEAR WHY ERNESTO HAS LOST ORGANIZATION SINCE THE OUTFLOW IS GOOD IN ALL DIRECTIONS...THE VERTICAL WIND SHEAR IS LIGHT...AND THE SEA SURFACE TEMPERATURES ARE WARM. ONE POSSIBLE
CAUSE MIGHT BE DRY AIR SEEN IN WATER VAPOR IMAGERY WEST OF THE CYCLONE
.
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2582. pottery
Quoting weathermanwannabe:
Some people don't listen (or read)....

:)

especially when they are f5-ing the NHC page continuously LOL.
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Are there any new model runs? If so, what are they suggesting? Thanks in advance.
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2580. Levi32
Quoting reedzone:


Well that settles the "open wave" argument.


Oh it's open. Not a single westerly reading from recon yet during the entire mission. NHC won't just discontinue advisories though. They do this a lot when a system is expected to easily regenerate a closed circulation in the near future.
Member Since: November 24, 2005 Posts: 635 Comments: 26731
I thought "RI flag" meant the storm's gonna hit Rhode Island
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Quoting TropicalAnalystwx13:
BULLETIN
TROPICAL STORM ERNESTO ADVISORY NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012
1100 PM EDT SAT AUG 04 2012

...HURRICANE HUNTER AIRCRAFT REPORTS ERNESTO HAS LOST SOME
ORGANIZATION...


SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...15.4N 72.7W
ABOUT 285 MI...455 KM SW OF SANTO DOMINGO DOMINICAN REPUBLIC
ABOUT 325 MI...525 KM ESE OF KINGSTON JAMAICA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 22 MPH...35 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES


Wow...
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Sigh. Long range guidance still uncertain, and intensity along with it.

Dynamical models say one thing, statistical something else.


Really is a troll storm.

NHC still says your wrong levi, they think its dry air lol.


You should go down there and bang a few doors down.
Member Since: June 24, 2012 Posts: 0 Comments: 1546
2576. MZT
The storm is close to 73W which means it's reaching the edge of the warm water stretching to the south of the islands. I'm not going to stay up all night to watch though
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right ok if that second vort message is the true LLCOC watch it through the morning if convection increases and explodes well that one is it and this one may do some RI

by the looks of it the convective ball seems to be drifting on top of it now
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Some people don't listen (or read)....
Member Since: Posts: Comments:
Quoting TropicalAnalystwx13:
BULLETIN
TROPICAL STORM ERNESTO ADVISORY NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012
1100 PM EDT SAT AUG 04 2012

...HURRICANE HUNTER AIRCRAFT REPORTS ERNESTO HAS LOST SOME
ORGANIZATION...


SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...15.4N 72.7W
ABOUT 285 MI...455 KM SW OF SANTO DOMINGO DOMINICAN REPUBLIC
ABOUT 325 MI...525 KM ESE OF KINGSTON JAMAICA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 22 MPH...35 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES


Well that settles the "open wave" argument.
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Quoting pottery:

Well done !


Hey it was your idea. All credit to you.
Member Since: Posts: Comments:
...HURRICANE HUNTER AIRCRAFT REPORTS ERNESTO HAS LOST SOME ORGANIZATION...
Member Since: Posts: Comments:
TROPICAL STORM ERNESTO DISCUSSION NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012
1100 PM EDT SAT AUG 04 2012

DESPITE AN IMPRESSIVE APPEARANCE IN INFRARED IMAGERY...MICROWAVE
IMAGERY AND REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER
AIRCRAFT INDICATE THAT ERNESTO HAS LOST SOME ORGANIZATION DURING
THE PAST SEVERAL HOURS. THE MICROWAVE DATA SUGGESTS THAT THE
LOW-LEVEL CENTER HAS BECOME PARTLY EXPOSED TO THE NORTHWEST OF THE
STRONG CONVECTION...AND THE AIRCRAFT REPORTS THAT THE CENTRAL
PRESSURE HAS RISEN TO 1007 MB. SINCE THE PLANE HAS NOT YET FULLY
SAMPLED THE NORTHEASTERN QUADRANT WHERE THE STRONGEST WINDS WERE
FOUND EARLIER...THE INITIAL INTENSITY IS HELD AT 50 KT. HOWEVER...
IT IS POSSIBLE THAT THIS ESTIMATE IS GENEROUS.

THE LOW-LEVEL CENTER HAS ACCELERATED WEST-NORTHWESTWARD SINCE THE
LAST ADVISORY...WITH A SHORT-TERM FORWARD SPEED OF OVER 20 KT. A
LONGER-TERM MOTION IS 285/19...WHICH IS THE INITIAL MOTION FOR THE
ADVISORY. THE REASON FOR THIS TRACK CHANGE IS UNCLEAR. HOWEVER...
THE GUIDANCE IS IN GOOD AGREEMENT THAT ERNESTO SHOULD RESUME A
WESTWARD MOTION DURING THE NEXT 12 HR OR SO ON THE SOUTH SIDE OF
THE SUBTROPICAL RIDGE. AFTER 24-36 HR...THE RIDGE SHOULD GRADUALLY
WEAKEN AS A MID/UPPER-LEVEL TROUGH DEVELOPS OVER THE EASTERN UNITED
STATES. WHILE SOME SPREAD REMAINS...THE GUIDANCE HAS COME INTO
BETTER AGREEMENT THAT ERNESTO WILL TURN WEST-NORTHWESTWARD AT A
REDUCED FORWARD SPEED AFTER 36 HR...MOVING OVER THE YUCATAN
PENINSULA OF MEXICO BETWEEN 72-96 HR AND REACHING THE SOUTHERN OR
SOUTHWESTERN GULF OF MEXICO BY THE END OF THE FORECAST PERIOD. THE
NEW FORECAST TRACK IS SHIFTED A LITTLE NORTH OF THE PREVIOUS TRACK
THROUGH 24 HR DUE TO THE INITIAL MOTION. HOWEVER...IT HAS BEEN
SHIFTED SOUTHWARD AFTER THAT TIME TO LIE NEAR THE VARIOUS CONSENSUS
MODELS. OVERALL...THE NEW FORECAST TRACK IS FASTER THAN THE
PREVIOUS TRACK.

IT IS ALSO UNCLEAR WHY ERNESTO HAS LOST ORGANIZATION SINCE THE
OUTFLOW IS GOOD IN ALL DIRECTIONS...THE VERTICAL WIND SHEAR IS
LIGHT...AND THE SEA SURFACE TEMPERATURES ARE WARM. ONE POSSIBLE
CAUSE MIGHT BE DRY AIR SEEN IN WATER VAPOR IMAGERY WEST OF THE
CYCLONE. THE DYNAMICAL GUIDANCE CONTINUES TO SUGGEST THAT ERNESTO
WILL NOT STRENGTHEN MUCH BEFORE REACHING THE NORTHWESTERN
CARIBBEAN...WHILE THE STATISTICAL-DYNAMICAL MODELS CONTINUE TO
FORECAST STEADY STRENGTHENING THROUGH THE FORECAST PERIOD. GIVEN
THE TRENDS DURING THE PAST 24 HR...THE NEW INTENSITY FORECAST CALLS
FOR A LOWER INTENSIFICATION RATE THAN THE PREVIOUS ADVISORY...WITH
ERNESTO BECOMING A HURRICANE IN 48 HR. GIVE THE DIVERGENT
GUIDANCE...THE INTENSITY FORECAST REMAINS OF LOW CONFIDENCE.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0300Z 15.4N 72.7W 50 KT 60 MPH
12H 05/1200Z 15.8N 75.5W 50 KT 60 MPH
24H 06/0000Z 16.1N 78.7W 50 KT 60 MPH
36H 06/1200Z 16.3N 81.0W 60 KT 70 MPH
48H 07/0000Z 17.0N 82.9W 65 KT 75 MPH
72H 08/0000Z 18.5N 86.5W 75 KT 85 MPH
96H 09/0000Z 20.5N 89.5W 70 KT 80 MPH...INLAND
120H 10/0000Z 22.0N 92.5W 65 KT 75 MPH...OVER WATER

$$
FORECASTER BEVEN
Member Since: July 6, 2010 Posts: 113 Comments: 33621

11:00 PM EDT Sat Aug 4
Location: 15.4°N 72.7°W
Moving: WNW at 22 mph
Min pressure: 1007 mb
Max sustained: 60 mph


Stand by for discussion
Member Since: June 24, 2012 Posts: 0 Comments: 1546
Quoting DataNerd:



Whats fascinating to me here is that the "new center" appears to have jogged NW from where the old one is.


As far as I can tell at this point its a very much broadened area of circulation as compared to just a few hours ago. Levi was right the trade winds really knocked it out of wack.


I guess its really anything goes at this point, will be interested to see what NHC says as there were 60 mph winds found in one area, well away from the center.





IS the weakness in the ridge tugging at the center? Is that feasible? Since earlier today the center jogged NW and now again to the NW?

Member Since: September 18, 2010 Posts: 0 Comments: 5296
2567. pottery
Quoting galvestonhurricane:


Thanks! No one else post it!

Well done !
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Quoting unknowncomic:
Looks like this would be a more serious situation later in the season with lighter trade winds.




Oh certainly without a doubt. Only issue would be whether El Nino was around by then or not.
Member Since: June 24, 2012 Posts: 0 Comments: 1546
BULLETIN
TROPICAL STORM ERNESTO ADVISORY NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012
1100 PM EDT SAT AUG 04 2012

...HURRICANE HUNTER AIRCRAFT REPORTS ERNESTO HAS LOST SOME
ORGANIZATION...


SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...15.4N 72.7W
ABOUT 285 MI...455 KM SW OF SANTO DOMINGO DOMINICAN REPUBLIC
ABOUT 325 MI...525 KM ESE OF KINGSTON JAMAICA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 22 MPH...35 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES
Member Since: July 6, 2010 Posts: 113 Comments: 33621
TROPICAL STORM ERNESTO FORECAST/ADVISORY NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012
0300 UTC SUN AUG 05 2012

CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* JAMAICA

A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS.

INTERESTS IN THE CAYMAN ISLANDS AND THE YUCATAN PENINSULA OF MEXICO
SHOULD MONITOR THE PROGRESS OF ERNESTO. A TROPICAL STORM WATCH MAY
BE REQUIRED FOR PORTIONS OF THE CAYMAN ISLANDS ON SUNDAY.

TROPICAL STORM CENTER LOCATED NEAR 15.4N 72.7W AT 05/0300Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 19 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1007 MB
MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT.
50 KT....... 25NE 0SE 0SW 0NW.
34 KT.......120NE 60SE 0SW 40NW.
12 FT SEAS..210NE 60SE 60SW 90NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 15.4N 72.7W AT 05/0300Z
AT 05/0000Z CENTER WAS LOCATED NEAR 15.3N 71.7W

FORECAST VALID 05/1200Z 15.8N 75.5W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 25NE 0SE 0SW 0NW.
34 KT...120NE 60SE 0SW 40NW.

FORECAST VALID 06/0000Z 16.1N 78.7W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 25NE 0SE 0SW 0NW.
34 KT...120NE 60SE 20SW 60NW.

FORECAST VALID 06/1200Z 16.3N 81.0W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 30NE 20SE 0SW 20NW.
34 KT...120NE 70SE 30SW 70NW.

FORECAST VALID 07/0000Z 17.0N 82.9W
MAX WIND 65 KT...GUSTS 80 KT.
50 KT... 40NE 30SE 20SW 30NW.
34 KT...120NE 70SE 40SW 70NW.

FORECAST VALID 08/0000Z 18.5N 86.5W
MAX WIND 75 KT...GUSTS 90 KT.
50 KT... 50NE 40SE 30SW 50NW.
34 KT...120NE 80SE 60SW 90NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 175 NM
ON DAY 4 AND 225 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 09/0000Z 20.5N 89.5W...INLAND
MAX WIND 70 KT...GUSTS 85 KT.

OUTLOOK VALID 10/0000Z 22.0N 92.5W...OVER WATER
MAX WIND 65 KT...GUSTS 80 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 15.4N 72.7W

NEXT ADVISORY AT 05/0900Z

$$
FORECASTER BEVEN
Member Since: July 6, 2010 Posts: 113 Comments: 33621
Not expecting NHC advisory until right at 11 they seem to be looking at things very carefully.
Member Since: June 24, 2012 Posts: 0 Comments: 1546
Quoting BahaHurican:
Am I the only person seeing a slowdown in forward motion???


I calculate 20 mph over the last two vortex fixes.
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Looks like this would be a more serious situation later in the season with lighter trade winds.
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Quoting AussieStorm:
Afternoon all. What have I missed in the last 10hrs. Not much I guess. Ernesto is almost a TD at 1007mb centre.

umm not even close to a t.d look at the winds, 60 MPH at the least
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Quoting DataNerd:
Recon still not done yet apparently going in for yet another pass.


Long mission :C
Good.
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Recon still not done yet apparently going in for yet another pass.


Long mission :C
Member Since: June 24, 2012 Posts: 0 Comments: 1546
NHC is taking their sweet time with this.
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2556. jpsb
Quoting redwagon:


Maybe the new COC will know what to do with DMAX.

This is so deja-vu...
Yup, this one is as bad as Debbie, lol and Debbie was a bad girl.
Member Since: June 30, 2009 Posts: 0 Comments: 1586
Quoting TomTaylor:


Glad to see you making your own, independent forecasts, though just a reminder, nearly all of the models are sold on the Yucatan peninsula at the moment.

Compare the 18z TAwx13 run to the 18z model spread

Also, I hope for the sake of our gulf coast residence that Ernesto defies your forecast lol. A strengthening major hurricane shooting the gap into the Gulf of Mexico would be horrible.

Yeah. Needless to say, that forecast will have to be shifted south and weaker. :P
Member Since: July 6, 2010 Posts: 113 Comments: 33621

Quoting TropicalAnalystwx13:
I don't usually do this, but I think Ernesto deserves it. From now on, I am disregarding all the models and using my brain. Let's look...

We've got an intensifying tropical storm/hurricane passing through the Central Caribbean. As it intensifies, it will move ever so slightly northward. When the system is located in the NW Caribbean, we've got a weakness across the northern Gulf Coast that would pick up any intense hurricane. So let's backtrack.

Sea Surface Temperatures in the NW Caribbean are near 29C. Ocean Heat Content Values are over 140 kJ/cm^2. Wind shear will be 5 knots or less. The environment will be moist. All good conditions for rapid to explosive intensification into a major hurricane. So let's go forward.

A major hurricane in the NW Caribbean would tend to move more poleward anyways, not to mention the fact that a weakness would be located along the northern Gulf Coast. The storm would pass through the Yucatan Channel (or clip the northern Yucatan) and then enter the central Gulf of Mexico. After that time, the trough moves out and ridging begins to build back in, forcing anything in the Gulf to Louisiana.

That's my thinking. Take it for what it's worth.
Glad to see you making your own, independent forecasts, though just a reminder, nearly all of the models are sold on the Yucatan peninsula at the moment.

Compare the 18z TAwx13 run to the 18z model spread

Also, I hope for the sake of our gulf coast residence that Ernesto defies your forecast lol. A strengthening major hurricane shooting the gap into the Gulf of Mexico would be horrible.
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Derived from (NHC) ATCF data for TropicalStormErnesto for 5August12amGMT:
MinimumPressure increased from 1003millibars to 1006millibars
MaxSusWinds held at 50knots(58mph)93km/h
Its vector changed from 286.5*WNWest@16.3mph(26.2km/h) to 287*WNWest@28mph(45km/h)

CTM-Chetumal :: MDB-Dangriga :: PUZ-PuertoCabezas :: PVA-Providencia

The Easternmost unlabeled dot marks Ernesto's position on its 30th hour as a TropicalStorm
The Easternmost dot on the longest line is TS.Ernesto's most recent position

The longest line is a straightline projection through TS.Ernesto's 2 most recent positions to its closest approach (within 18miles or 29 kilometres) to a coastline
4August12amGMT: TS.Ernesto had been headed for passage 7.6miles(12.2kilometres)South of Providencia (PVA-blob)
4August6amGMT: TS.Ernesto had been headed for passage over MiskitoCays (PUZ-dumbbell)
4August12pmGMT: TS.Ernesto had been headed for passage over GalesPoint (MDB-blob)
4August6pmGMT: TS.Ernesto had been headed for passage over ElPlacer,QuintanaRoo (CTM-dumbbell)
5August12amGMT: TS.Ernesto was heading for passage over Mosquitero,QuintanRoo within the SianKa'anBiosphereReserve in ~1day12hours from now (when this comment was posted)

Copy&paste eyw, ctm-18.883n87.642w, mdb-17.23n88.304w, puz-14.32n82.6w, pva-13.323n81.391w-13.213n81.384w, stx, 13.8n64.8w-13.9n66.4w, 13.9n66.4w-14.2n67.9w, 14.2n67.9w-14.6n69.3w, 14.6n69.3w-15.3n71.7w, 14.6n69.3w-19.15n87.642w into the GreatCircleMapper for a larger-scale map and other information
The previous mapping for comparison.
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Quoting Levi32:


Trade winds! Nobody seems to get it yet, after 36 hours of me fighting the blog over it, and Ernesto still hasn't strengthened. Does anybody believe me yet lol.
I'm right there with you Levi. Have been all along.

It's not the convectively coupled kelvin wave, it's not dry air, and it's certainly nothing to do with the upper level environment.

Recon, ASCAT, and model intializations and forecasts have consistently shown the circulation being weak to the SW or S. Why? Because it's hard to get winds from the west when they are accelerating to the west out in front of the storm.
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Thank you for the answers. Appreciated.
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Quoting Levi32:


It's very warm up there above the eye, always. The change in major hurricanes comes because there are two things that drive the upper-level heights above the storm. One is the net atmospheric pressure at the surface. As that goes down, the heights fall. The other thing is the temperature, which due to latent heat release, is very warm above the storm, which raises heights, and is why upper-level highs develop above tropical cyclones.

The change to cyclonic vorticity above the eye as high as 200mb in intense hurricanes comes when the pressure falls at the surface overcome the effect of latent heat release, and cause the heights at that level to fall below those of the surrounding environment, thus creating low pressure at that level. However, it is still warm-core, just like the rest of the hurricane vortex. The vortex has now just become strong enough to become present up that high. Remember hurricanes as they intensify acquire stronger cyclonic vorticity at successively higher levels in the atmosphere.


This is new info for me...thanks Levi! Ur final sentence there also bolsters why stronger trpoical cyclones more-or-less "feel" upper features and can be steered a bit more by such upper featuers as they get stronger....
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2549. scott39
Quoting BahaHurican:
Am I the only person seeing a slowdown in forward motion???
It may be starting to but the last 6 hour average movement was 27mph. 12 hour 22mph
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Quoting BahaHurican:
Am I the only person seeing a slowdown in forward motion???




It does appear to have slowed SLIGHTLY


But I doubt that's meaningful probably has more to do with COC re-organizing then anything.
Member Since: June 24, 2012 Posts: 0 Comments: 1546
Quoting jpsb:
Rapid Intensification.


Maybe the new COC will know what to do with DMAX.

This is so deja-vu...
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2546. scott39
15.3N 71.7W
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Am I the only person seeing a slowdown in forward motion???
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