EPAC: CALVIN - Remnants

[cycloneye]

TROPICAL STORM CALVIN DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL EP032011
200 PM PDT SAT JUL 09 2011

VISIBLE AND MICROWAVE SATELLITE IMAGERY SHOWS THAT CALVIN CONTINUES
TO WEAKEN QUICKLY...WITH THE CENTER NOW EXPOSED TO THE EAST OF A
DIMINISHING AREA OF CONVECTION. THE INITIAL INTENSITY IS SET AT 40
KT USING A BLEND OF DVORAK CI AND FINAL-T NUMBERS FROM TAFB AND
SAB...AND A 1745 UTC ASCAT PASS THAT SHOWED A SMALL PATCH OF 35-40
KT WINDS EAST OF THE CENTER. CONTINUED WEAKENING IS FORECAST AS THE
CYCLONE MOVES OVER EVEN COLDER WATERS AND THE OFFICIAL FORECAST
SHOWS CALVIN BECOMING A REMNANT LOW BY TOMORROW IN AGREEMENT WITH
THE SHIPS AND LGEM. DISSIPATION IS EXPECTED WITHIN 48 TO 72
HOURS...BUT COULD OCCUR SOONER.

THE CENTER IS LOCATED A LITTLE NORTHEAST OF PREVIOUS ESTIMATES...BUT
THE INITIAL MOTION REMAINS TOWARD THE WEST-NORTHWEST OR 285 DEGREES
AT 8 KNOTS. AS CALVIN CONTINUES TO WEAKEN...IT WILL BE STEERED
GENERALLY WEST-NORTHWESTWARD BY THE LOW-LEVEL FLOW UNTIL
DISSIPATION. THE NEW NHC FORECAST IS ESSENTIALLY AN UPDATE OF THE
PREVIOUS ONE AFTER ADJUSTING FOR THE INITIAL POSITION.

THE 34-KT WIND RADII HAVE BEEN ADJUSTED INWARD BASED ON 09/1734Z
ASCAT SCATTEROMETER DATA.

FORECAST POSITIONS AND MAX WINDS

INIT 09/2100Z 17.4N 111.7W 40 KT 45 MPH
12H 10/0600Z 17.8N 113.0W 30 KT 35 MPH
24H 10/1800Z 18.3N 114.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 11/0600Z 18.8N 116.2W 20 KT 25 MPH...POST-TROP/REMNT LOW
48H 11/1800Z 19.3N 117.6W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 12/1800Z...DISSIPATED

$$
FORECASTER BRENNAN/STEWART

[Rgv20]

Calvin not looking to good...RIP


No hard feelings toward Calvin I was forecasting a minimal TS and he became a hurricane.. lol

[cycloneye]

Final Advisory

POST-TROPICAL CYCLONE CALVIN DISCUSSION NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL EP032011
800 PM PDT SAT JUL 09 2011

INFRARED AND MICROWAVE SATELLITE IMAGERY INDICATE THAT CALVIN HAS
CONTINUED TO RAPIDLY DEGENERATE. THERE HAS BEEN NO ORGANIZED DEEP
CONVECTION NEAR THE LOW-LEVEL CENTER FOR NEARLY 9 HOURS NOW...AND A
09/2037Z AMSU OVERPASS INDICATED THAT THE UPPER-LEVEL WARM CORE HAD
DISSIPATED WITH ONLY A WEAK WARM CORE REMAINING NEAR THE 500 MB
LEVEL. ALTHOUGH A SMALL THUNDERSTORM WITH TOPS COLDER THAN -70C HAS
RECENTLY DEVELOPED ABOUT 70 NMI SOUTHWEST OF THE CENTER...THIS
CONVECTION IS LIKELY NOT PROVIDING ANY POSITIVE FEEDBACK ON THE
INNER CORE OF THE LOW. AS A RESULT...CALVIN HAS BEEN DECLARED A
NON-CONVECTIVE REMNANT LOW PRESSURE SYSTEM. THE INITIAL INTENSITY
IS SET AT 30 KT BASED ON AN EXPECTED SPINDOWN OF 35-40 KT WINDS
THAT WERE NOTED IN AN EARLIER 09/1734Z ASCAT SATELLITE OVERPASS.

THE INITIAL MOTION ESTIMATE IS 285/09. THE REMNANT LOW IS EXPECTED
TO MOVE SLOWLY WEST-NORTHWESTWARD OVER COLDER WATER FOR THE NEXT 2
DAYS AS THE CIRCULATION REMAINS EMBEDDED IN SHALLOW LOW-LEVEL
EASTERLY TRADE WIND FLOW. GIVEN MUCH COOLER WATERS AND MORE STABLE
AIR AHEAD OF THE REMNANT LOW...REDEVELOPMENT OF ANY ORGANIZED DEEP
CONVECTION NEAR THE LOW-LEVEL CENTER IS UNLIKELY.

12-FT SEAS RADII HAVE BEEN INCLUDED SINCE CALVIN ONLY RECENTLY LOST
ITS STATUS AS A TROPICAL CYCLONE...AND IT WILL TAKE A FEW MORE
HOURS FOR THE SEAS TO SUBSIDE.

THIS IS THE FINAL NHC ADVISORY ON CALVIN. FOR ADDITIONAL INFORMATION
ON THE REMNANT LOW...PLEASE SEE HIGH SEAS FORECASTS ISSUED BY THE
NATIONAL WEATHER SERVICE...UNDER AWIPS HEADER NFDHSFEPI AND WMO
HEADER FZPN02 KWBC.

FORECAST POSITIONS AND MAX WINDS

INIT 10/0300Z 17.7N 112.6W 30 KT 35 MPH
12H 10/1200Z 18.0N 113.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 11/0000Z 18.5N 115.4W 20 KT 25 MPH...POST-TROP/REMNT LOW
36H 11/1200Z 19.0N 116.9W 20 KT 25 MPH...POST-TROP/REMNT LOW
48H 12/0000Z 19.5N 118.4W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 13/0000Z...DISSIPATED

$$
FORECASTER STEWART