Tropical Depression Alvin=Last Advisory Written

[Thunder44]

Tropical Depression One-E Discussion Number 1

Statement as of 8:00 PM PDT on May 26, 2007



convection associated with the low pressure area well southwest of
Manzanillo Mexico has increased significantly during the past
several hours...with tops of colder than -80c developing over the
center. Satellite intensity estimates are 30 kt from TAFB and 25
kt from SAB. Based on all this...advisories are initiated on
Tropical Depression One-E.
The initial motion is a somewhat uncertain 265/4. Water vapor
imagery shows a large and complex mid/upper-level trough over
Mexico and the adjacent Pacific waters north of 20n east of 115w...
with a large mid/upper-level ridge covering the region west of
115w. This leaves the depression in an area of weak steering flow.
The large-scale models forecast the trough to move eastward and the
ridge to slowly build north of the depression during the forecast
period. This should allow a slow westward motion as forecast by
the GFDL...the ECMWF...and the Canadian models. The official
forecast follows this scenario...calling for a slow westward motion
under the ridge through 120 hr. A potential complicating factor is
the possibility that another tropical cyclone will form east of the
depression...as forecast by the GFS...NOGAPS...and UKMET models.
Should this occur...this could cause Tropical Depression One-E to
have erratic motion.
The depression is currently in an environment of difluent
southeasterly upper-level winds and moderate vertical shear. The
depression should remain in a light-to-moderate shear environment
over warm water for 48-72 hr...which should allow strengthening.
The intensity forecast calls for the cyclone to reach 60 kt in 72
hr...which is slightly above the SHIPS and GFDL forecasts. After
that...the forecast track takes the system over gradually cooling
sea surface temperatures...which should start a weakening trend.
Forecast positions and Max winds

initial 27/0300z 12.6n 110.8w 30 kt
12hr VT 27/1200z 12.5n 111.5w 35 kt
24hr VT 28/0000z 12.4n 112.6w 45 kt
36hr VT 28/1200z 12.3n 113.5w 50 kt
48hr VT 29/0000z 12.3n 114.4w 55 kt
72hr VT 30/0000z 12.5n 116.0w 60 kt
96hr VT 31/0000z 12.5n 118.0w 60 kt
120hr VT 01/0000z 13.0n 121.0w 55 kt

$$
forecaster Beven

[Tampa Bay Hurricane]

No surprise, -84 C cloud tops and localized potent convection
did the trick.

[Chacor]

WTPZ21 KNHC 270231
TCMEP1
TROPICAL DEPRESSION ONE-E FORECAST/ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP012007
0300 UTC SUN MAY 27 2007

TROPICAL DEPRESSION CENTER LOCATED NEAR 12.6N 110.8W AT 27/0300Z
POSITION ACCURATE WITHIN 25 NM

PRESENT MOVEMENT TOWARD THE WEST OR 265 DEGREES AT 4 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1006 MB
MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.
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 12.6N 110.8W AT 27/0300Z
AT 27/0000Z CENTER WAS LOCATED NEAR 12.6N 110.6W

FORECAST VALID 27/1200Z 12.5N 111.5W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 45NE 45SE 0SW 0NW.

FORECAST VALID 28/0000Z 12.4N 112.6W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 50NE 50SE 40SW 50NW.

FORECAST VALID 28/1200Z 12.3N 113.5W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 30NE 0SE 0SW 30NW.
34 KT... 60NE 60SE 50SW 60NW.

FORECAST VALID 29/0000Z 12.3N 114.4W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 30NE 25SE 25SW 30NW.
34 KT... 70NE 60SE 60SW 70NW.

FORECAST VALID 30/0000Z 12.5N 116.0W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 35NE 30SE 30SW 35NW.
34 KT... 80NE 60SE 60SW 80NW.

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 31/0000Z 12.5N 118.0W
MAX WIND 60 KT...GUSTS 75 KT.

OUTLOOK VALID 01/0000Z 13.0N 121.0W
MAX WIND 55 KT...GUSTS 65 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 12.6N 110.8W

NEXT ADVISORY AT 27/0900Z

$$
FORECASTER BEVEN

[cycloneye]

No threat to any landmasses except shipping lanes.

[HURAKAN]

Geographical Oops:

[AnnularCane]

Geographical Oops:

Now how did that happen?

Amazing. Just this afternoon I thought he was dead, and now look. You'd think I'd have learned by now not to write them off so quickly.

And there might be another one soon?

[JonathanBelles]

They put 110E instead of 110W on the coordinates.

[Cyclenall]

We finally have TD1-E and it just formed 8-10 hours earlier then TS Aletta did from last year. It's even going to flirt with hurricane strength (60 knots). Not bad.

They put 110E instead of 110W on the coordinates.

Nice catch, that explains why several websites that have tropical cyclone information have the same problem. It's all automatic by the computer. They should fix that.

A POTENTIAL COMPLICATING FACTOR IS
THE POSSIBILITY THAT ANOTHER TROPICAL CYCLONE WILL FORM EAST OF THE
DEPRESSION...AS FORECAST BY THE GFS...NOGAPS...AND UKMET MODELS.

This would be cool. I did notice a few of the models developing another low that looks like it's coming from the ITCZ.

[Chacor]

000
WTPZ21 KNHC 270831
TCMEP1
TROPICAL DEPRESSION ONE-E FORECAST/ADVISORY NUMBER 2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP012007
0900 UTC SUN MAY 27 2007

TROPICAL DEPRESSION CENTER LOCATED NEAR 12.8N 111.2W AT 27/0900Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST OR 270 DEGREES AT 4 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1006 MB
MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.
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 12.8N 111.2W AT 27/0900Z
AT 27/0600Z CENTER WAS LOCATED NEAR 12.8N 111.0W

FORECAST VALID 27/1800Z 12.8N 111.8W
MAX WIND 30 KT...GUSTS 40 KT.

FORECAST VALID 28/0600Z 12.8N 112.6W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 50NE 50SE 40SW 50NW.

FORECAST VALID 28/1800Z 12.8N 113.4W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 50NE 50SE 40SW 50NW.

FORECAST VALID 29/0600Z 12.8N 114.2W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 30NE 0SE 0SW 30NW.
34 KT... 60NE 60SE 50SW 60NW.

FORECAST VALID 30/0600Z 12.8N 116.0W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 30NE 25SE 25SW 30NW.
34 KT... 70NE 60SE 60SW 70NW.

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 31/0600Z 12.8N 118.0W
MAX WIND 55 KT...GUSTS 65 KT.

OUTLOOK VALID 01/0600Z 12.8N 120.5W
MAX WIND 50 KT...GUSTS 60 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 12.8N 111.2W

NEXT ADVISORY AT 27/1500Z

$$
FORECASTER BLAKE

[hr]

000
WTPZ41 KNHC 270840
TCDEP1
TROPICAL DEPRESSION ONE-E DISCUSSION NUMBER 2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP012007
200 AM PDT SUN MAY 27 2007

THE TROPICAL DEPRESSION IS SENDING MIXED MESSAGES THIS MORNING. AN
EARLIER QUIKSCAT PASS AT 0146 UTC SHOWED SEVERAL BELIEVABLE WIND
SPEEDS JUST BELOW STORM STRENGTH. A LITTLE LATER...AT 0338 UTC...
SSMIS MICROWAVE DATA SHOWED A CURVED BAND STRUCTURE AROUND THE
CENTER. HOWEVER...SINCE THESE MICROWAVE DATA...THE CONVECTIVE
ORGANIZATION OF THE SYSTEM HAS BEEN DETERIORATING. AN EARLIER
IMPRESSIVE BAND TO THE SOUTH OF THE CENTER HAS BEEN DRAMATICALLY
WEAKENING. THE CENTER...AS DERIVED FROM EARLIER MICROWAVE
PASSES...NOW SEEMS TO BE ON THE NORTHERN SIDE OF THE REMAINING DEEP
CONVECTION. IT IS A LITTLE ODD THAT THUNDERSTORMS ARE
PREFERENTIALLY FORMING ON THE SOUTHEASTERN PORTION OF THE
CIRCULATION WHEN THE SHEAR IS COMING FROM THE SOUTHEAST...PERHAPS
INDICATIVE OF THE GENERAL LACK OF ORGANIZATION AT THIS TIME. IN
ANY EVENT...SATELLITE CLASSIFICATIONS REMAIN BELOW TROPICAL STORM
STRENGTH AND THE INITIAL INTENSITY WILL STAY AT 30 KT.

FOR THE MOMENT...WITH THE CENTER ON THE NORTHERN PART OF THE
CONVECTIVE MASS...ANY INTENSIFICATION IS TEMPORARILY HALTED.
HOWEVER WATER VAPOR IMAGES SHOW THAT THE DEPRESSION IS UNDER THE
INFLUENCE OF UPPER RIDGING WITH ONLY MODEST SOUTHEASTERLY SHEAR.
THIS PATTERN SHOULD ALLOW FOR MORE STRENGTHENING LATER ON AS
A LOW TO MODERATE SHEAR ENVIRONMENT IS FORECAST TO PERSIST FOR
AT LEAST 3 DAYS BY THE GLOBAL MODELS. IN ADDITION...SSTS WILL
REMAIN PLENTY WARM...SO INTENSIFICATION IS FORECAST. THE ONLY
OBVIOUS NEGATIVE FOR FURTHER DEVELOPMENT IS THE ENTRAINMENT OF MORE
STABLE AIR INTO THE NORTHERN PORTION OF THE CIRCULATION...WHICH
SHOULD BE MINIMIZED IF THE CYCLONE CONTINUES MOVING WESTWARD.
VERTICAL WIND SHEAR COULD INCREASE BEYOND THREE DAYS SO THE
INTENSITY FORECAST WILL BE NUDGED DOWNWARD AT THAT TIME-FRAME.

THE INITIAL MOTION ESTIMATE IS WESTWARD...270/4. A MIDDLE- TO
UPPER-LEVEL TROUGH OVER MEXICO HAS PASSED THE DEPRESSION AND LEFT
IT IN AN AREA OF WEAK STEERING CONDITIONS. RIDGING TO THE NORTHWEST
OF THE SYSTEM SHOULD STEER IT SLOWLY WESTWARD FOR A COUPLE DAYS.
THEREAFTER...UPPER RIDGING IS FORECAST TO BUILD TO THE NORTH OF THE
DEPRESSION...WHICH SHOULD ENCOURAGE A FASTER WESTWARD MOTION. THIS
IS THE APPROXIMATE SOLUTION PRESENTED BY THE ECMWF AND THE CANADIAN
MODEL. HOWEVER... OTHER GLOBAL MODELS HAVE SLOWER SOLUTIONS...
SEEMINGLY STRUGGLING WITH AN AREA OF DISTURBED WEATHER TO THE EAST
OF THE DEPRESSION. THE GFS... NOGAPS AND UKMET (TO SOME EXTENT)
FORECAST THAT THE SYSTEM BEHIND THE DEPRESSION WILL BECOME LARGER
AND STRONGER RATHER QUICKLY... WHICH SLOWS THE MOTION OF THE
DEPRESSION. FOR NOW...GIVEN THE RELATIVE BENIGN APPEARANCE ON
SATELLITE OF THE SECOND SYSTEM...A FASTER SOLUTION WILL BE FAVORED.
THE OFFICIAL FORECAST IS SLOWER THAN THE PREVIOUS FORECAST PACKAGE
BUT FASTER THAN MOST OF THE GUIDANCE.

FORECAST POSITIONS AND MAX WINDS

INITIAL 27/0900Z 12.8N 111.2W 30 KT
12HR VT 27/1800Z 12.8N 111.8W 30 KT
24HR VT 28/0600Z 12.8N 112.6W 40 KT
36HR VT 28/1800Z 12.8N 113.4W 45 KT
48HR VT 29/0600Z 12.8N 114.2W 50 KT
72HR VT 30/0600Z 12.8N 116.0W 55 KT
96HR VT 31/0600Z 12.8N 118.0W 55 KT
120HR VT 01/0600Z 12.8N 120.5W 50 KT

$$
FORECASTER BLAKE

[Aquawind]

Not to impressive this morning on IR. Some deep convection yet..but still the circulation does not look stacked. A new ball of convection should refire soon..

[Mike Doran]

http://webflash.ess.washington.edu/WWLL ... as_BIG.gif

Last night as this was named td1 with the peak of lighting banding features extended all way south past 0 degrees and then to the north into fair weather from the ITCZ in the EPAC. Then as the lightning for the evening fizzled, so did those banding features. Solar wind is high well above 500 km/second but decreasing.

[Chacor]

038
WTPZ21 KNHC 271439
TCMEP1
TROPICAL DEPRESSION ONE-E FORECAST/ADVISORY NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP012007
1500 UTC SUN MAY 27 2007

TROPICAL DEPRESSION CENTER LOCATED NEAR 13.0N 111.2W AT 27/1500Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST OR 280 DEGREES AT 3 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1006 MB
MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.
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 13.0N 111.2W AT 27/1500Z
AT 27/1200Z CENTER WAS LOCATED NEAR 13.0N 111.1W

FORECAST VALID 28/0000Z 13.1N 111.7W
MAX WIND 30 KT...GUSTS 40 KT.

FORECAST VALID 28/1200Z 13.1N 112.4W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 50NE 50SE 50SW 50NW.

FORECAST VALID 29/0000Z 13.1N 113.2W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 50NE 50SE 50SW 50NW.

FORECAST VALID 29/1200Z 13.0N 114.2W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 60NE 50SE 50SW 60NW.

FORECAST VALID 30/1200Z 13.0N 116.0W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 30NE 0SE 0SW 30NW.
34 KT... 60NE 0SE 0SW 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 31/1200Z 13.0N 118.5W
MAX WIND 50 KT...GUSTS 60 KT.

OUTLOOK VALID 01/1200Z 12.5N 120.5W
MAX WIND 50 KT...GUSTS 60 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 13.0N 111.2W

NEXT ADVISORY AT 27/2100Z

$$
FORECASTER FRANKLIN

[hr]
036
WTPZ41 KNHC 271439
TCDEP1
TROPICAL DEPRESSION ONE-E DISCUSSION NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP012007
800 AM PDT SUN MAY 27 2007

MICROWAVE PASSES AT 0847 AND 1004 UTC PROVIDED GOOD CENTER
FIXES...AND SHOWED THAT THE CENTER OF THE DEPRESSION IS WELL TO THE
NORTH AND EAST OF THE MAIN...AND POORLY ORGANIZED...CONVECTIVE
AREAS. SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE 35 AND
30 KT...RESPECTIVELY...AND GIVEN RECENT CONVECTIVE TRENDS THE
ADVISORY INTENSITY WILL REMAIN 30 KT. ALTHOUGH THE WATERS BELOW
ARE WARM AND THE SHEAR IS NOT PROHIBITIVE...THE THERMODYNAMICS OF
THE ENVIRONMENT APPEAR TO BE INHIBITING DEVELOPMENT...WITH MUCH OF
THE LOW-LEVEL FLOW INTO THE DEPRESSION FROM THE NORTHWEST. BOTH
SHIPS AND THE LGE-SHIPS MODELS HAVE TRENDED DOWNWARD WITH THEIR
EXPECTATIONS FOR THIS SYSTEM. IT SHOULD BE NOTED THAT THE GFS
GRADUALLY DISSIPATES THE CYCLONE INTO THE ITCZ AS IT DEVELOPS A NEW
CYCLONE TO ITS EAST. ALTHOUGH THE NEW CYCLOGENESIS SEEMS
OVERDONE...THE MODEL MAY WELL BE CORRECT ABOUT THE DEVELOPMENT
PROSPECTS OF THE DEPRESSION. THE OFFICIAL FORECAST...FOR
NOW...REMAINS CLOSE TO SHIPS GUIDANCE.

THE INITIAL MOTION ESTIMATE IS 280/3. THE DEPRESSION IS IN A WEAK
STEERING ENVIRONMENT...WITH A MID-LEVEL TROUGH CURRENTLY PASSING TO
ITS NORTH. A LARGE MID-LEVEL RIDGE NORTHWEST OF THE DEPRESSION IS
FORECAST TO MOVE NORTHEASTWARD...WHICH IS EXPECTED TO RESULT IN A
SLOW WESTWARD TRACK OF THE CYCLONE THROUGH THE FORECAST PERIOD.
THIS IS THE SOLUTION OFFERED BY THE ECMWF AND THE ONE FOLLOWED BY
THE OFFICIAL FORECAST. THE BAM MODELS ARE SIMILAR BUT SOMEWHAT
FASTER. ON THE OTHER HAND...THE UKMET KEEPS THE RIDGE MORE IN
PLACE...BLOCKING THE DEPRESSION AND KEEPING THE MOTION VERY SLOW.
EVEN MORE EXTREME ARE THE SOLUTIONS OF THE GFS/NOGAPS/GFDL...WHICH
SHOW AN INTERACTION WITH THE AFOREMENTIONED MODEL CYCLOGENESIS TO
THE EAST THAT RESULTS IN A SOUTHWARD AND THEN EASTWARD MOTION FOR
THE DEPRESSION. THERE DOES NOT APPEAR TO BE ANY EVIDENCE OF SUCH
CYCLOGENESIS AT THIS TIME...AND THIS LATTER SCENARIO IS CONSIDERED
UNLIKELY.


FORECAST POSITIONS AND MAX WINDS

INITIAL 27/1500Z 13.0N 111.2W 30 KT
12HR VT 28/0000Z 13.1N 111.7W 30 KT
24HR VT 28/1200Z 13.1N 112.4W 35 KT
36HR VT 29/0000Z 13.1N 113.2W 40 KT
48HR VT 29/1200Z 13.0N 114.2W 45 KT
72HR VT 30/1200Z 13.0N 116.0W 50 KT
96HR VT 31/1200Z 13.0N 118.5W 50 KT
120HR VT 01/1200Z 12.5N 120.5W 50 KT

$$
FORECASTER FRANKLIN

[WmE]

CIMSS is giving it a T2.6 rating which means TS, just FWIW. I doubt that it is a TS right now.

[benny]

ugly! all that is left is a swirl. i suppose this system has always looked better in the late afternoon/evening.. but if it wants to remain a TC, better get some convection near the center!

[AnnularCane]

Awww, he looks like Chris.


"ALTHOUGH THE WATERS BELOW
ARE WARM AND THE SHEAR IS NOT PROHIBITIVE...THE THERMODYNAMICS OF
THE ENVIRONMENT APPEAR TO BE INHIBITING DEVELOPMENT..."


What does this mean? What's wrong?

[JonathanBelles]

He looks nakey!

[windstorm99]

Here's a view of TS Chris...Naked swirl

[wxmann_91]

Awww, he looks like Chris.


"ALTHOUGH THE WATERS BELOW
ARE WARM AND THE SHEAR IS NOT PROHIBITIVE...THE THERMODYNAMICS OF
THE ENVIRONMENT APPEAR TO BE INHIBITING DEVELOPMENT..."


What does this mean? What's wrong?

Thermodynamics --> instability needed to sustain deep convection/strength of convection, etc

Basically, stable air is being ingested into the circulation...

[Nimbus]

The naked swirl of TD 1E appears to be rolling WNW across the 28 degree SST line into cooler water. Doesn't look like this is going to get very exciting even if 1E does manage to pull in some of that warm moist air to its west. One more good burst of convection could technically make 1E meet the criteria for tropical storm status.

[JonathanBelles]

What is that straight line of clouds coming out of the NE side of TD1E?