EPAC : TROPICAL DEPRESSION CARLOS (04E)

[Ed Mahmoud]

Don't get me wrong. Overall the thesis looks good and there's some great stuff in there. My point is that you cannot take a hypothesis from a thesis (that lack of wind shear prevents dry air intrusion, which he states in his summary is, indeed, only a hypothesis), and claim it as an absolute, as he did here.

Thus, "dry air cannot get into a storm if there is no shear" does not equal "it was hypothesized that strong shear allows the dry air to penetrate into the inner core region of the TC."

Suffice to say that I'm a professional met, have been for a long time (longer than I'd like to admit), and although I won't claim to be one of the TC "gods" by any stretch, I'm quite well qualified to discuss tropical cyclones.

Get a "Blue Nic" then by contacting the admins. When I see two pro-mets disagree, I try to watch and learn.

When I see what I assume is a well informed amateur doubting a pro-met, I assume the pro-met is correct. Especially if the pro-met is Derek, who, along with senorpepr, is one of two pro-mets who regularly visits the sports forum here during the off-season.

If they had a petroleum engineering forum, and people argued over rock mechanic properties or whatever, I'd want the blue nic so people would know I am the voice of experience.

[Derek Ortt]

still has an eye on microwave

however, it has moved WSW

You think 96E has a big enough circulation to affect the steering of Carlos?

I think they're far enough apart

[HURAKAN]

Convection remains weak.

[tolakram]

Nothing much to offer except:

http://www.ssd.noaa.gov/goes/flt/t7/flash-avn.html

The SST display is bugged, the 'cool pool' just shifted to the west along with Carlos.

These storms are fascinating to watch. Mysterious lack of convection but what there is, to my eye, looks highly organized.

[cycloneye]

45 kts

635
WTPZ34 KNHC 131456
TCPEP4
BULLETIN
TROPICAL STORM CARLOS ADVISORY NUMBER 14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042009
800 AM PDT MON JUL 13 2009

AT 800 AM PDT...1500 UTC...THE CENTER OF TROPICAL STORM CARLOS WAS
LOCATED NEAR LATITUDE 9.6 NORTH...LONGITUDE 125.3 WEST OR ABOUT 1370
MILES...2210 KM...SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA.

CARLOS IS MOVING A LITTLE SOUTH OF DUE WEST NEAR 14 MPH...22
KM/HR...BUT IS EXPECTED TO MOVE ON A GENERAL WESTWARD TRACK WITH
LITTLE CHANGE IN SPEED OVER THE NEXT COUPLE OF DAYS.

MAXIMUM SUSTAINED WINDS ARE NEAR 50 MPH...85 KM/HR...WITH HIGHER
GUSTS. LITTLE CHANGE IN STRENGTH IS EXPECTED DURING THE NEXT 48
HOURS.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 60 MILES...95 KM
FROM THE CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 997 MB...29.44 INCHES.

...SUMMARY OF 800 AM PDT INFORMATION...
LOCATION...9.6N 125.3W
MAXIMUM SUSTAINED WINDS...50 MPH
PRESENT MOVEMENT...WEST OR 260 DEGREES AT 14 MPH
MINIMUM CENTRAL PRESSURE...997 MB

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
200 PM PDT.

$$
FORECASTER BERG




579
WTPZ24 KNHC 131455
TCMEP4
TROPICAL STORM CARLOS FORECAST/ADVISORY NUMBER 14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042009
1500 UTC MON JUL 13 2009

TROPICAL STORM CENTER LOCATED NEAR 9.6N 125.3W AT 13/1500Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST OR 260 DEGREES AT 12 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 997 MB
MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT.
34 KT....... 50NE 50SE 30SW 50NW.
12 FT SEAS..120NE 60SE 30SW 120NW.
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 9.6N 125.3W AT 13/1500Z
AT 13/1200Z CENTER WAS LOCATED NEAR 9.8N 124.7W

FORECAST VALID 14/0000Z 9.6N 127.1W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 20NE 0SE 0SW 20NW.
34 KT... 60NE 50SE 30SW 60NW.

FORECAST VALID 14/1200Z 9.9N 129.3W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 20NE 0SE 0SW 20NW.
34 KT... 60NE 50SE 30SW 60NW.

FORECAST VALID 15/0000Z 10.2N 131.5W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 30NE 0SE 0SW 30NW.
34 KT... 60NE 60SE 45SW 60NW.

FORECAST VALID 15/1200Z 10.5N 133.5W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 30NE 0SE 0SW 30NW.
34 KT... 60NE 60SE 45SW 60NW.

FORECAST VALID 16/1200Z 11.0N 137.5W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 30NE 0SE 0SW 30NW.
34 KT... 60NE 60SE 45SW 60NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 200 NM
ON DAY 4 AND 225 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 17/1200Z 11.5N 142.0W
MAX WIND 50 KT...GUSTS 60 KT.

OUTLOOK VALID 18/1200Z 11.5N 148.0W
MAX WIND 40 KT...GUSTS 50 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 9.6N 125.3W

NEXT ADVISORY AT 13/2100Z

$$
FORECASTER BERG

WTPZ44 KNHC 131456
TCDEP4
TROPICAL STORM CARLOS DISCUSSION NUMBER 14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042009
800 AM PDT MON JUL 13 2009

A 1045 UTC TRMM MICROWAVE PASS INDICATES THAT CARLOS HAS BEEN MOVING
SOUTH OF DUE WEST AT 260/12 OVER THE PAST FEW HOURS AND IS A LITTLE
FARTHER SOUTH THAN PREVIOUSLY ESTIMATED. THE SAME PASS IS ALSO
SHOWING THAT THE CONVECTIVE BANDING MAY BE BECOMING A LITTLE MORE
ORGANIZED AROUND THE CENTER. HOWEVER...THE SATELLITE INTENSITY
ESTIMATES STILL SUPPORT AN INITIAL INTENSITY OF 45 KT.

WHEREAS IT APPEARED THAT CARLOS WAS DETACHING FROM THE ITCZ A COUPLE
OF DAYS AGO...SATELLITE IMAGERY NOW SUGGESTS THAT IT HAS BECOME
RE-ATTACHED TO THE AXIS. THIS MIGHT BE CONTRIBUTING TO THE WEST TO
WEST-SOUTHWESTERLY MOTION OVER THE PAST 12-24 HOURS. THE GUIDANCE
ENVELOPE STILL SUGGESTS THAT CARLOS SHOULD GAIN SOME LATITUDE
DURING THE NEXT 48 HOURS...BUT THE RECENT MOTION MAKES THIS
SCENARIO UNCERTAIN. THE NEW OFFICIAL FORECAST IS SIMILAR TO THE
PREVIOUS FORECAST EXCEPT THAT IT IS SHIFTED AS MUCH AS A DEGREE
FARTHER SOUTH TO ACCOUNT FOR THE UPDATED INITIAL POSITION.

CARLOS' INVOLVEMENT WITH THE ITCZ COMPLICATES THE INTENSITY
FORECAST. IF THE CYCLONE CONTINUES TO MOVE WEST-SOUTHWESTWARD ALONG
THE AXIS...RE-STRENGTHENING WOULD BE HIGHLY UNLIKELY. IN
FACT...SOME OF THE MORE RELIABLE GLOBAL MODELS...PARTICULARLY THE
GFS AND ECMWF...KEEP CARLOS EMBEDDED WITHIN THE ITCZ AND OPEN IT
INTO A TROUGH VERY SOON. THE HWRF IS ALSO PESSIMISTIC AND
ESSENTIALLY DISSIPATES THE CYCLONE IN A FEW DAYS. CONVERSELY...THE
SHIPS/LGEM GUIDANCE SHOWS VERY LITTLE CHANGE IN INTENSITY OVER THE
NEXT 5 DAYS WHILE THE GFDL RE-STRENGTHENS THE SYSTEM TO A
HURRICANE. THE OFFICIAL INTENSITY FORECAST REMAINS UNCHANGED FROM
THE PREVIOUS ADVISORY EXCEPT THAT IT BRINGS THE INTENSITY DOWN A
LITTLE FASTER BY DAY 5 DUE TO INCREASING VERTICAL SHEAR. WHILE THE
OFFICIAL WIND SPEED PROBABILITY PRODUCT INDICATES A 50% CHANCE THAT
CARLOS WILL BE A DEPRESSION OR DISSIPATED BY DAY 5...I SUSPECT THE
CHANCES ARE HIGHER THAN THAT.

FORECAST POSITIONS AND MAX WINDS

INITIAL 13/1500Z 9.6N 125.3W 45 KT
12HR VT 14/0000Z 9.6N 127.1W 50 KT
24HR VT 14/1200Z 9.9N 129.3W 50 KT
36HR VT 15/0000Z 10.2N 131.5W 55 KT
48HR VT 15/1200Z 10.5N 133.5W 55 KT
72HR VT 16/1200Z 11.0N 137.5W 55 KT
96HR VT 17/1200Z 11.5N 142.0W 50 KT
120HR VT 18/1200Z 11.5N 148.0W 40 KT

$$
FORECASTER BERG

[Lurker]

Wow outstanding call on this one!! Please keep posting - your insights are great.

Think this should remain steady state over the next few days... the models were correct. Gulped down a little too much dry air poison (or shear), and that's certainly not going away anytime soon. The good news is that with this system weaker, it might take a more equatorial path that will keep it south of HI.

[HURAKAN]

Little Carlos.

[HURAKAN]

WOW, the eye is back!

[Macrocane]

It has improved its organization, the banding is better and the center is under he strongest convection, if the trend continue maybe it will be a little stronger for the next advisory.

[HurricaneRobert]

It looks like a hurricane again.

[Derek Ortt]

but it still looks pathetic on the IR

[cycloneye]

18 UTC Best Track increase winds to 55kts

EP, 04, 2009071318, , BEST, 0, 95N, 1256W, 55, 994, TS

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 009.invest

[HURAKAN]

Not looking as good as before but at least the convection is stronger.

[CrazyC83]

13/1800 UTC 9.5N 125.6W T4.0/4.0 CARLOS -- East Pacific

Hurricane again at 2100Z? Or 60 kt to be conservative?

[cycloneye]

WTPZ34 KNHC 132034
TCPEP4
BULLETIN
TROPICAL STORM CARLOS ADVISORY NUMBER 15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042009
200 PM PDT MON JUL 13 2009

...TINY CARLOS STRENGTHENS AGAIN...

AT 200 PM PDT...2100 UTC...THE CENTER OF TROPICAL STORM CARLOS WAS
LOCATED NEAR LATITUDE 9.4 NORTH...LONGITUDE 126.1 WEST OR ABOUT 1420
MILES...2285 KM...SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA.

CARLOS IS MOVING TOWARD THE WEST-SOUTHWEST NEAR 12 MPH. A GENERAL
WESTWARD MOTION AT THIS FORWARD SPEED IS EXPECTED OVER THE NEXT
COUPLE OF DAYS.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 65 MPH...100
KM/HR...WITH HIGHER GUSTS. FLUCTUATIONS IN INTENSITY ARE
POSSIBLE...BUT LITTLE OVERALL CHANGE IN STRENGTH IS FORECAST
DURING THE NEXT 48 HOURS.

CARLOS IS A SMALL TROPICAL CYCLONE. TROPICAL STORM FORCE WINDS
EXTEND OUTWARD UP TO 35 MILES...55 KM FROM THE CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 994 MB...29.35 INCHES.

...SUMMARY OF 200 PM PDT INFORMATION...
LOCATION...9.4N 126.1W
MAXIMUM SUSTAINED WINDS...65 MPH
PRESENT MOVEMENT...WEST-SOUTHWEST OR 255 DEGREES AT 12 MPH
MINIMUM CENTRAL PRESSURE...994 MB

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
800 PM PDT.

$$
FORECASTER BERG

016
WTPZ44 KNHC 132036
TCDEP4
TROPICAL STORM CARLOS DISCUSSION NUMBER 15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042009
200 PM PDT MON JUL 13 2009

AN EYE-LIKE FEATURE APPEARED IN VISIBLE IMAGERY AROUND 1700 UTC BUT
HAS SINCE BEEN PARTIALLY COVERED BY A SMALL CENTRAL DENSE OVERCAST.
SUBJECTIVE SATELLITE INTENSITY ESTIMATES ARE NOW 3.5 FROM TAFB AND
4.0 FROM SAB...AND THE OBJECTIVE ADT IS HOVERING AROUND 3.3. IN
ADDITION...AN AMBIGUITY ANALYSIS OF A 1433 UTC QUIKSCAT PASS
INDICATED THAT THE INTENSITY OF CARLOS WAS AT LEAST 45-50 KT. THE
INITIAL INTENSITY IS SET AT 55 KT AS A CONSENSUS. THE QUIKSCAT
PASS ALSO INDICATED THAT TROPICAL STORM FORCE WINDS ONLY EXTEND 30
N MI FROM THE CENTER.

CARLOS CONTINUES TO MOVE WITH A SOUTHWARD COMPONENT AT 255/10. THE
CYCLONE IS ATTACHED TO A CONVERGENCE BAND...PART OF THE ITCZ...THAT
EXTENDS ALMOST 1000 N MI TO THE WEST-SOUTHWEST. IT DOES NOT APPEAR
THAT CARLOS IS STRONG ENOUGH OR BIG ENOUGH AT THIS POINT TO
OVERCOME THIS FEATURE...AND THERE IS SOME CONCERN THAT IT WILL
CONTINUE MOVING WEST-SOUTHWESTWARD AND NOT SURVIVE. WITH THE
ASSUMPTION THAT THE CYCLONE PERSISTS...THE OFFICIAL TRACK FORECAST
KEEPS CARLOS NEAR THE SOUTHERN EDGE OF THE GUIDANCE ENVELOPE.
CARLOS' SMALL SIZE HAS ALSO MADE IT...AND WILL PROBABLY CONTINUE TO
MAKE IT...SUSCEPTIBLE TO SHORT-TERM INTENSITY CHANGES THAT WE DO
NOT HAVE SKILL IN FORECASTING. AS A RESULT...THE OFFICIAL
INTENSITY FORECAST HOLDS CARLOS AT 55 KT FOR THE NEXT 72 HOURS WITH
THE RECOGNITION THAT THE INTENSITY COULD OSCILLATE A LITTLE ABOVE
AND BELOW THIS VALUE. ULTIMATELY...WEAKENING IS EXPECTED AFTER 72
HOURS DUE TO INCREASING VERTICAL SHEAR. NEEDLESS TO SAY...THE
UNCERTAINTY IN THIS FORECAST IS LARGER THAN NORMAL.

FORECAST POSITIONS AND MAX WINDS

INITIAL 13/2100Z 9.4N 126.1W 55 KT
12HR VT 14/0600Z 9.5N 127.8W 55 KT
24HR VT 14/1800Z 9.7N 130.1W 55 KT
36HR VT 15/0600Z 10.0N 132.2W 55 KT
48HR VT 15/1800Z 10.4N 134.2W 55 KT
72HR VT 16/1800Z 11.0N 138.5W 55 KT
96HR VT 17/1800Z 11.5N 144.5W 50 KT
120HR VT 18/1800Z 11.5N 151.5W 40 KT

$$
FORECASTER BERG

[jinftl]

Strong ts...or is it just a strong thunderstorm given the size??? LOL

Excerpts from latest advisory and discussion:

CARLOS IS A SMALL TROPICAL CYCLONE. TROPICAL STORM FORCE WINDS
EXTEND OUTWARD UP TO 35 MILES...55 KM FROM THE CENTER.

CARLOS' SMALL SIZE HAS ALSO MADE IT...AND WILL PROBABLY CONTINUE TO
MAKE IT...SUSCEPTIBLE TO SHORT-TERM INTENSITY CHANGES THAT WE DO
NOT HAVE SKILL IN FORECASTING.

[CrazyC83]

It might even be stronger since Dvorak performs poorly with tiny storms. But we'll never know, since there is no Recon anywhere near there and no surface obs.

[Iune]

Forecast Advisory 16 is out

000
WTPZ24 KNHC 140233
TCMEP4
TROPICAL STORM CARLOS FORECAST/ADVISORY NUMBER 16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042009
0300 UTC TUE JUL 14 2009

TROPICAL STORM CENTER LOCATED NEAR 9.7N 127.0W AT 14/0300Z
POSITION ACCURATE WITHIN 15 NM

PRESENT MOVEMENT TOWARD THE WEST OR 270 DEGREES AT 9 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 994 MB
MAX SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT.
50 KT....... 20NE 0SE 0SW 20NW.
34 KT....... 30NE 30SE 30SW 30NW.
12 FT SEAS..120NE 60SE 30SW 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 9.7N 127.0W AT 14/0300Z
AT 14/0000Z CENTER WAS LOCATED NEAR 9.6N 126.5W

FORECAST VALID 14/1200Z 9.7N 128.4W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 20NE 0SE 0SW 20NW.
34 KT... 30NE 30SE 30SW 30NW.

FORECAST VALID 15/0000Z 9.9N 130.3W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 25NE 0SE 0SW 25NW.
34 KT... 45NE 30SE 30SW 45NW.

FORECAST VALID 15/1200Z 10.2N 132.3W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 25NE 0SE 0SW 25NW.
34 KT... 45NE 30SE 30SW 45NW.

FORECAST VALID 16/0000Z 10.5N 134.2W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 25NE 0SE 0SW 25NW.
34 KT... 45NE 30SE 30SW 45NW.

FORECAST VALID 17/0000Z 11.3N 138.8W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 25NE 0SE 0SW 25NW.
34 KT... 45NE 30SE 30SW 45NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 200 NM
ON DAY 4 AND 225 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 18/0000Z 11.5N 145.5W
MAX WIND 45 KT...GUSTS 55 KT.

OUTLOOK VALID 19/0000Z 11.5N 152.0W
MAX WIND 40 KT...GUSTS 50 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 9.7N 127.0W

NEXT ADVISORY AT 14/0900Z

$$
FORECASTER BROWN

[HurricaneRobert]

I can believe that. Convection is the deepest its been all day. How far could Carlos make it if it travels a course that is straight west?

[Cyclenall]

Yesterday's Thoughts:

Hurricane Carlos (now Tropical Storm!) is becoming a problem cyclone. It's doing things that cannot be explained and going against predictions. I at least wasn't saying this was undergoing RI because it actually wasn't this time, just very quick strengthening at 15 knots in 6 hours which is close. Instead of becoming a major or CAT4, it instead weakened to a TS...which means the last advisory yesterday was off by 30 knots.

Looking at the HWRF model runs, amazingly it showed it maintaining itself throughout the 120 hour period as a moderate CAT1 hurricane but then the next run (6 hours later) LOSES it and shows a open wave at the end. This was Sunday's model runs. I'm curious as to what it's going to do next.

Today's Thoughts:

The last three NHC discussions have been really interesting to read. I have never seen a mature hurricane re-attach itself back to the ITCZ and I didn't even think that was possible. I wonder if that is what is causing all of this right back to Saturday evening. If I was assigning values for intensity for the next 5 days, I would just keep it at 55 knots all the way through. The NHC is starting that now with the 2nd latest forecast.

Another thing that is amazing is how small TS Carlos is right now compared to 60 hours ago. How did it shrink like that? When looking at Invest 96E beside it, it's comical. The last few days of Hurricane/TS Carlos' life has been incredible in terms of surprising developments.

CARLOS' INVOLVEMENT WITH THE ITCZ COMPLICATES THE INTENSITY FORECAST. IF THE CYCLONE CONTINUES TO MOVE WEST-SOUTHWESTWARD ALONG THE AXIS...RE-STRENGTHENING WOULD BE HIGHLY UNLIKELY.

What is the scientific reasoning for when a 55 knot TS gets caught up in the ITCZ that it begins to weaken? What is it exactly that causes it to falter?

Like have already said, the farther south, the better for Carlos.

Ironically enough, that could also destroy Carlos per what the NHC thinks will happen if it kept going west-southwest.

To Iceman56, are you a tropical meteorologist? Either way, nice to have to here discussing on the tropics!