EPAC: ALVIN - Post-Tropical

[cycloneye]

These kind of systems that don't affect land are great to follow.

[CrazyC83]

Hey (soon-to-be) Alvin! It looks like we might get a hurricane right out of the gate...

I wonder if you are on a mission to find Simon and Theodore! (even though if they were on the lists, they would be late in the season)

[Yellow Evan]

Hey (soon-to-be) Alvin! It looks like we might get a hurricane right out of the gate...

I wonder if you are on a mission to find Simon and Theodore! (even though if they were on the lists, they would be late in the season)

I think we could see R, but further discussion should IMO be in the 2013 PHS thread.

[cycloneye]

Still TD at 18z Best Track:

EP, 01, 2013051518, , BEST, 0, 84N, 1045W, 30, 1006, TD

ftp://ftp.nhc.noaa.gov/atcf/tcweb/inves ... 013.invest

[cycloneye]

We have the first named storm of the EPAC season ALVIN!!


TROPICAL STORM ALVIN DISCUSSION NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL EP012013
200 PM PDT WED MAY 15 2013

ASCAT DATA FROM AROUND 1612 UTC SHOWED THAT THE DEPRESSION HAD WINDS
VERY NEAR THE THRESHOLD FOR A TROPICAL STORM. THE CLOUD PATTERN IN
VISIBLE IMAGERY HAS BECOME MORE ORGANIZED SINCE THE TIME OF THAT
PASS...AND IT IS LIKELY THAT THE SYSTEM HAS BECOME A TROPICAL
STORM. THE INTENSITY IS BEING SET AT 35 KT.

THE ASCAT PASS ALSO HELPED TO BETTER LOCATE THE LOW-LEVEL
CENTER...AND THE INITIAL MOTION ESTIMATE IS NOW 290 DEGREES AT 11
KT. ALVIN IS ON THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL RIDGE
THAT EXTENDS SOUTHWESTWARD FROM MAINLAND MEXICO OVER THE
PACIFIC...AND THIS FEATURE SHOULD CONTINUE TO STEER THE STORM
WEST-NORTHWESTWARD FOR THE NEXT FEW DAYS. A MID-LEVEL TROUGH IS
FORECAST TO AMPLIFY NEAR CALIFORNIA COAST IN 2 TO 3 DAYS...CREATING
A WEAKNESS IN THE RIDGE. THERE IS A SIGNIFICANT SPLIT IN THE MODEL
GUIDANCE WITH THE STRONGER GFS AND GFDL SHOWING A TURN TOWARD THE
NORTH AND THE WEAKER ECMWF AND UKMET MODELS SHOWING A CONTINUED
WESTWARD MOTION BY DAY 5. THE OFFICIAL FORECAST SOMEWHAT SPLITS
THE DIFFERENCE BUT DOES FAVOR THE SCENARIO OF A STRONGER
NORTHWESTWARD-TURNING STORM.

MOST OF THE INTENSITY GUIDANCE SUPPORTS ALVIN REACHING HURRICANE
STRENGTH IN A FEW DAYS. THE DYNAMICAL GFDL AND HWRF MODELS ARE THE
MOST AGGRESSIVE...BUT EVEN THE SHIPS MODEL SHOWS ALVIN GETTING
STRONGER THAN WE INDICATED IN THE PREVIOUS OFFICIAL FORECAST.
ALVIN IS ABOUT TO MOVE OVER A WARM POOL OF WATER WITH SEA SURFACE
TEMPERATURES AROUND 30.5C...AND VERTICAL SHEAR SHOULD BE MINIMAL
FOR AT LEAST THE NEXT 3 DAYS. THE NHC INTENSITY FORECAST CONTINUES
TO SHOW A STEADY INTENSIFICATION AND HAS BEEN BUMPED UP SLIGHTLY
FROM THE PREVIOUS FORECAST THROUGH DAY 3. FASTER STRENGTHENING IS
POSSIBLE...AND THE RAPID INTENSIFICATION INDEX NOW SHOWS A 1 IN 3
CHANCE OF A 30-KT INCREASE IN WINDS OVER THE NEXT 24 HOURS.
WEAKENING SHOULD BE UNDERWAY IN 4 TO 5 DAYS MAINLY DUE TO STRONGER
VERTICAL WIND SHEAR.

FORECAST POSITIONS AND MAX WINDS

INIT 15/2100Z 8.7N 105.1W 35 KT 40 MPH
12H 16/0600Z 9.3N 106.5W 40 KT 45 MPH
24H 16/1800Z 10.0N 108.2W 50 KT 60 MPH
36H 17/0600Z 10.6N 109.8W 60 KT 70 MPH
48H 17/1800Z 11.1N 111.4W 70 KT 80 MPH
72H 18/1800Z 12.5N 114.0W 75 KT 85 MPH
96H 19/1800Z 14.0N 116.0W 60 KT 70 MPH
120H 20/1800Z 15.5N 117.5W 40 KT 45 MPH

$$
FORECASTER BERG

[Dave]

TROPICAL STORM ALVIN ADVISORY NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL EP012013
200 PM PDT WED MAY 15 2013

...DEPRESSION BECOMES FIRST TROPICAL STORM OF THE EASTERN PACIFIC
SEASON...

SUMMARY OF 200 PM PDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...8.7N 105.1W
ABOUT 665 MI...1070 KM SSW OF ACAPULCO MEXICO
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES

WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 200 PM PDT...2100 UTC...THE CENTER OF TROPICAL STORM ALVIN WAS
LOCATED NEAR LATITUDE 8.7 NORTH...LONGITUDE 105.1 WEST. ALVIN IS
MOVING TOWARD THE WEST-NORTHWEST NEAR 13 MPH...20 KM/H. A SLIGHT
DECREASE IN FORWARD SPEED IS EXPECTED DURING THE NEXT 48 HOURS.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 40 MPH...65 KM/H...
WITH HIGHER GUSTS. ADDITIONAL STRENGTHENING IS FORECAST DURING THE
NEXT 48 HOURS...AND ALVIN COULD BECOME A HURRICANE IN A COUPLE OF
DAYS.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 35 MILES...55 KM TO
THE NORTHEAST OF THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB...29.68 INCHES.

HAZARDS AFFECTING LAND
----------------------
NONE

[Kingarabian]

Looking at IR, he's wrapping around nicely. Wheres Mr.Brunota ?

[SouthDadeFish]

Decent banding on this 19Z TRMM pass:



Here is the 37 GHz color:

[Hurricane Jed]

This is a nice looking tropical storm. Best 40mph tropical storm I can remember seeing in a long time.

[galaxy401]

Just in time! Let's see how it progresses.

[SouthDadeFish]

Visible satellite shows some nice poleward outflow:

[TropicalAnalystwx13]

I think this system has caught a lot of people, including myself, off guard. Just yesterday morning it was a disturbance with disorganized convection and no low-level circulation (just mid-level). It rapidly developed a surface low yesterday evening and intensified it as convection developed atop the center and elsewhere.

With RH values over 70%, wind shear under 10 knots, and SSTs above [at least] 28C through 96 hours, Alvin should be a quickly-intensifying cyclone during this time. I wouldn't be surprised to see a hurricane tomorrow night or Friday, with peak intensity on Saturday. It may reach upper-end Category 1 intensity.

[Kingarabian]

Why aren't there ADT numbers on this?

[TropicalAnalystwx13]

CIMSS:

2013MAY15 194500 2.6 1010.7 37.0 2.6 2.8 2.8 NO LIMIT OFF OFF -44.56 -56.88 CRVBND N/A N/A 8.43 104.49 FCST GOES13 35.6

SAB:

15/2345 UTC 8.5N 105.3W T2.5/2.5 ALVIN -- East Pacific

0z ATCF update:

EP, 01, 2013051600, , BEST, 0, 88N, 1055W, 40, 1004, TS

[Meow]

I think this system has caught a lot of people, including myself, off guard. Just yesterday morning it was a disturbance with disorganized convection and no low-level circulation (just mid-level). It rapidly developed a surface low yesterday evening and intensified it as convection developed atop the center and elsewhere.

With RH values over 70%, wind shear under 10 knots, and SSTs above [at least] 28C through 96 hours, Alvin should be a quickly-intensifying cyclone during this time. I wouldn't be surprised to see a hurricane tomorrow night or Friday, with peak intensity on Saturday. It may reach upper-end Category 1 intensity.

People should focus on Cyclonic Storm Mahasen more. It is killing many people in India and Bangladesh, yet Alvin is harmless forever.

[supercane4867]

People should focus on Cyclonic Storm Mahasen more. It is killing many people in India and Bangladesh, yet Alvin is harmless forever.

You should say this to some of the careless WPAC fans who show no interest in other basins at all

[Yellow Evan]

I think this system has caught a lot of people, including myself, off guard. Just yesterday morning it was a disturbance with disorganized convection and no low-level circulation (just mid-level). It rapidly developed a surface low yesterday evening and intensified it as convection developed atop the center and elsewhere.

With RH values over 70%, wind shear under 10 knots, and SSTs above [at least] 28C through 96 hours, Alvin should be a quickly-intensifying cyclone during this time. I wouldn't be surprised to see a hurricane tomorrow night or Friday, with peak intensity on Saturday. It may reach upper-end Category 1 intensity.

People should focus on Cyclonic Storm Mahasen more. It is killing many people in India and Bangladesh, yet Alvin is harmless forever.

I could argue that a fish storm makes it fun to track. I do agree however that the NIO/SHEM gets too little attention, but I also feel that way with the EPAC. But, I am starting to think Alvin will become a major if everything goes well.

[Yellow Evan]

000
WTPZ21 KNHC 160241
TCMEP1

TROPICAL STORM ALVIN FORECAST/ADVISORY NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL EP012013
0300 UTC THU MAY 16 2013

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 9.0N 105.9W AT 16/0300Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 290 DEGREES AT 10 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1004 MB
MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT.
34 KT....... 40NE 20SE 0SW 40NW.
12 FT SEAS.. 90NE 0SE 0SW 45NW.
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 9.0N 105.9W AT 16/0300Z
AT 16/0000Z CENTER WAS LOCATED NEAR 8.8N 105.5W

FORECAST VALID 16/1200Z 9.5N 107.3W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 20NE 0SE 0SW 20NW.
34 KT... 60NE 40SE 20SW 60NW.

FORECAST VALID 17/0000Z 10.2N 109.0W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 30NE 20SE 0SW 30NW.
34 KT... 80NE 50SE 30SW 70NW.

FORECAST VALID 17/1200Z 10.9N 110.5W
MAX WIND 70 KT...GUSTS 85 KT.
64 KT... 20NE 10SE 0SW 15NW.
50 KT... 40NE 30SE 20SW 40NW.
34 KT...100NE 60SE 50SW 90NW.

FORECAST VALID 18/0000Z 11.6N 111.9W
MAX WIND 80 KT...GUSTS 100 KT.
50 KT... 50NE 40SE 30SW 50NW.
34 KT...110NE 70SE 60SW 100NW.

FORECAST VALID 19/0000Z 13.0N 114.0W
MAX WIND 75 KT...GUSTS 90 KT.
50 KT... 50NE 40SE 30SW 50NW.
34 KT...100NE 70SE 60SW 100NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 20/0000Z 14.7N 116.0W
MAX WIND 55 KT...GUSTS 65 KT.

OUTLOOK VALID 21/0000Z 16.0N 117.3W
MAX WIND 35 KT...GUSTS 45 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 9.0N 105.9W

NEXT ADVISORY AT 16/0900Z

$$
FORECASTER KIMBERLAIN

[Yellow Evan]

000
WTPZ31 KNHC 160242
TCPEP1

BULLETIN
TROPICAL STORM ALVIN ADVISORY NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL EP012013
800 PM PDT WED MAY 15 2013

...ALVIN STRENGTHENING...


SUMMARY OF 800 PM PDT...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...9.0N 105.9W
ABOUT 700 MI...1125 KM S OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES


WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 800 PM PDT...0300 UTC...THE CENTER OF TROPICAL STORM ALVIN WAS
LOCATED NEAR LATITUDE 9.0 NORTH...LONGITUDE 105.9 WEST. ALVIN IS
MOVING TOWARD THE WEST-NORTHWEST NEAR 12 MPH...19 KM/H...AND THIS
MOTION WITH A GRADUAL DECREASE IN FORWARD SPEED IS EXPECTED DURING
THE NEXT COUPLE OF DAYS.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 45 MPH...75
KM/H...WITH HIGHER GUSTS. ADDITIONAL STRENGTHENING IS FORECAST
DURING THE NEXT 48 HOURS...AND ALVIN IS EXPECTED TO BECOME A
HURRICANE BY FRIDAY.

TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 45 MILES...75 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB...29.65 INCHES.


HAZARDS AFFECTING LAND
----------------------
NONE


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...200 AM PDT.

$$
FORECASTER KIMBERLAIN

[cycloneye]

TROPICAL STORM ALVIN DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL EP012013
800 PM PDT WED MAY 15 2013

ALVIN IS STRENGTHENING. SATELLITE DATA DURING THE LAST SEVERAL HOURS
SHOWS A WELL-DEFINED BAND WRAPPING A LITTLE MORE THAN HALFWAY
AROUND THE CIRCULATION. A BURST OF CONVECTION HAS ALSO RECENTLY
FORMED NEAR THE CENTER...POSSIBLY THE BEGINNINGS OF A CENTRAL DENSE
OVERCAST. SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB WERE 2.5
AT 0000 UTC. SINCE THAT TIME...HOWEVER...THE CONVECTIVE
ORGANIZATION OF ALVIN HAS INCREASED FURTHER. ON THIS BASIS...THE
INITIAL INTENSITY IS RAISED TO 40 KT.

THE INITIAL MOTION ESTIMATE IS 290/11. ALVIN SHOULD CONTINUE MOVING
WEST-NORTHWESTWARD AROUND THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL
RIDGE CENTERED OVER SOUTHERN MEXICO DURING THE NEXT COUPLE OF DAYS.
AFTER THAT TIME...THE MODEL GUIDANCE DIVERGES RATHER SIGNIFICANTLY
AS A RESULT OF DIFFERING MODEL SOLUTIONS REGARDING THE STRENGTH OF
THE VORTEX AND THEIR HANDLING OF A MID- TO UPPER-LEVEL TROUGH
PASSING THROUGH THE SOUTHWESTERN UNITED STATES. THE GFS DEPICTS A
STRONGER SYSTEM THAT FEELS THE EFFECT OF A MORE AMPLIFIED EXTENSION
OF THE ABOVE TROUGH TO THE NORTHWEST OF ALVIN. ON THE OTHER HAND...
THE UKMET AND ECMWF MAINTAIN A WEAKER SYSTEM AND A LESS AMPLIFIED
TROUGH NORTHWEST OF THE CYCLONE...AND HENCE HAVE A MORE WESTERLY
COURSE. ALTHOUGH THE OFFICIAL FORECAST GENERALLY SPLITS THE
DIFFERENCE BETWEEN THE GUIDANCE...IT CONTINUES TO LEAN SOMEWHAT
MORE ON THE STRONGER GFS SOLUTION...PLACING THE TRACK FORECAST
SLIGHTLY RIGHT OF THE PREVIOUS ONE AND NEAR THE MULTI-MODEL
CONSENSUS TVCE. GIVEN THE DISPARATE TRACK GUIDANCE...HOWEVER...THE
CONFIDENCE IN THE TRACK FORECAST IS LOWER THAN NORMAL.

ALVIN IS FORECAST TO REMAIN IN A FAVORABLE LOCATION TO THE SOUTH OF
AN UPPER-LEVEL RIDGE AXIS DURING THE NEXT DAY OR TWO. THIS SHOULD
PROVIDE A LOW-SHEAR ENVIRONMENT AS THE CYCLONE MOVES OVER VERY WARM
WATERS...LIKELY RESULTING IN ADDITIONAL INTENSIFICATION. IN FACT...
THE SHIPS RAPID INTENSIFICATION INDICATES A NEARLY 1 IN 2 CHANCE OF
A 30-KT INCREASE IN INTENSITY DURING THE NEXT 24 HOURS. AFTER
THAT...THE GFS KEEPS ALVIN IN A LOW SHEAR ENVIRONMENT OVER SLOWLY
DECREASING SEA SURFACE TEMPERATURES UNTIL DAYS 4-5...WHEN THE SHEAR
INCREASES ABRUPTLY. THE ECMWF/UKMET SHOW ALVIN ENCOUNTERING
WESTERLY SHEAR MUCH SOONER...WHICH WOULD STIFLE ANY SIGNIFICANT
INTENSIFICATION. THE NHC INTENSITY FORECAST PLACES MORE WEIGHT ON
THE STRONGER GFS SOLUTION AND REPRESENTS A BLEND OF THE LATEST
SHIPS...DYNAMICAL...AND FSSE GUIDANCE.


FORECAST POSITIONS AND MAX WINDS

INIT 16/0300Z 9.0N 105.9W 40 KT 45 MPH
12H 16/1200Z 9.5N 107.3W 50 KT 60 MPH
24H 17/0000Z 10.2N 109.0W 60 KT 70 MPH
36H 17/1200Z 10.9N 110.5W 70 KT 80 MPH
48H 18/0000Z 11.6N 111.9W 80 KT 90 MPH
72H 19/0000Z 13.0N 114.0W 75 KT 85 MPH
96H 20/0000Z 14.7N 116.0W 55 KT 65 MPH
120H 21/0000Z 16.0N 117.3W 35 KT 40 MPH

$$
FORECASTER KIMBERLAIN