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Post-Tropical Cyclone Wanda Forecast Discussion Number 31

  000 WTNT41 KNHC 071447 TCDAT1  Post-Tropical Cyclone Wanda Discussion Number  31 NWS National Hurricane Center Miami FL       AL212021 300 PM GMT Sun Nov 07 2021  Wanda is no longer generating deep convection in association with  its low-level circulation. In fact, most of the colder cloud tops  seen on satellite over the center right now are actually upper-level  cirrus associated with a cold frontal boundary part of a  larger mid-latitude cyclone southeast of Greenland. In addition, an  1156 UTC ASCAT-B pass over Wanda's circulation shows that the north  side is beginning to open up into a trough as the cold front is  encroaching on the system. These above factors suggest that Wanda is  no longer a tropical cyclone, and the system is now classified as a  post-tropical low as of this advisory. The winds remain 35-kt based  on the peak wind retrieval of 33-kt from the scatterometer data on  the southeast side of the circulation.  The system has been accelerating to the northeast with the latest estimated motion at 045/22 kt. The post-tropical cyclone should continue to accelerate to the northeast until it merges with the baroclinic zone approaching it. A 12 hour point is provided for continuity and to indicate the transition to an extratropical cyclone, though its quite possible the system will be fully absorbed by the frontal boundary by then. The track guidance at 12 hours is tightly clustered, and the NHC track forecast at that time fame follows the consensus aids closely.  This is the last NHC advisory on Wanda.  Additional information on  this system can be found in High Seas Forecasts issued by Meteo  France under WMO header FQNT50 LFPW and available on the web at www.meteofrance.com/previsions-meteo-marine/bulletin/grandlarge/ metarea2.   FORECAST POSITIONS AND MAX WINDS  INIT  07/1500Z 40.2N  33.5W   35 KT  40 MPH...POST-TROPICAL  12H  08/0000Z 43.5N  29.1W   35 KT  40 MPH...POST-TROP/EXTRATROP  24H  08/1200Z...DISSIPATED  $$ Forecaster Papin  

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Post-Tropical Cyclone Wanda Graphics


Coastal Watches/Warnings and Forecast Cone for Storm Center

Forecast Length* Forecast Track Line Initial Wind Field






cone graphic

* If the storm is forecast to dissipate within 3 days, the “Full Forecast” and “3 day” graphic will be identical

Click Here for a 5-day Cone Printer Friendly Graphic

How to use the cone graphic (video):

Link to video describing cone graphic

About this product:

This graphic shows an approximate representation of coastal areas under a hurricane warning (red), hurricane watch (pink), tropical storm warning (blue) and tropical storm watch (yellow). The orange circle indicates the current position of the center of the tropical cyclone. The black line, when selected, and dots show the National Hurricane Center (NHC) forecast track of the center at the times indicated. The dot indicating the forecast center location will be black if the cyclone is forecast to be tropical and will be white with a black outline if the cyclone is forecast to be extratropical. If only an L is displayed, then the system is forecast to be a remnant low. The letter inside the dot indicates the NHC’s forecast intensity for that time:

D: Tropical Depression – wind speed less than 39 MPH

S: Tropical Storm – wind speed between 39 MPH and 73 MPH

H: Hurricane – wind speed between 74 MPH and 110 MPH

M: Major Hurricane – wind speed greater than 110 MPH

NHC tropical cyclone forecast tracks can be in error. This forecast uncertainty is conveyed by the track forecast “cone”, the solid white and stippled white areas in the graphic. The solid white area depicts the track forecast uncertainty for days 1-3 of the forecast, while the stippled area depicts the uncertainty on days 4-5. Historical data indicate that the entire 5-day path of the center of the tropical cyclone will remain within the cone about 60-70% of the time. To form the cone, a set of imaginary circles are placed along the forecast track at the 12, 24, 36, 48, 72, 96, and 120 h positions, where the size of each circle is set so that it encloses 67% of the previous five years official forecast errors. The cone is then formed by smoothly connecting the area swept out by the set of circles.

It is also important to realize that a tropical cyclone is not a point. Their effects can span many hundreds of miles from the center. The area experiencing hurricane force (one-minute average wind speeds of at least 74 mph) and tropical storm force (one-minute average wind speeds of 39-73 mph) winds can extend well beyond the white areas shown enclosing the most likely track area of the center. The distribution of hurricane and tropical storm force winds in this tropical cyclone can be seen in the Wind History graphic linked above.

Considering the combined forecast uncertainties in track, intensity, and size, the chances that any particular location will experience winds of 34 kt (tropical storm force), 50 kt, or 64 kt (hurricane force) from this tropical cyclone are presented in tabular form for selected locations and forecast positions. This information is also presented in graphical form for the 34 kt, 50 kt, and 64 kt thresholds.

Note:  A detailed definition of the NHC track forecast cone is also available.

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Post-Tropical Cyclone Wanda Wind Speed Probabilities Number 31

  000 FONT11 KNHC 071446 PWSAT1  POST-TROPICAL CYCLONE WANDA WIND SPEED PROBABILITIES NUMBER  31      NWS NATIONAL HURRICANE CENTER MIAMI FL       AL212021                1500 UTC SUN NOV 07 2021                                              AT 1500Z THE CENTER OF POST-TROPICAL CYCLONE WANDA WAS LOCATED NEAR  LATITUDE 40.2 NORTH...LONGITUDE 33.5 WEST WITH MAXIMUM SUSTAINED     WINDS NEAR 35 KTS...40 MPH...65 KM/H.                                 Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH)                      ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME          EASTERN  STANDARD TIME (EST)...SUBTRACT 5 HOURS FROM Z TIME          CENTRAL  STANDARD TIME (CST)...SUBTRACT 6 HOURS FROM Z TIME        WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS                   CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST         ...34 KT (39 MPH... 63 KM/H)...                                      ...50 KT (58 MPH... 93 KM/H)...                                      ...64 KT (74 MPH...119 KM/H)...                                   FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS                 PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE                    OP  IS THE PROBABILITY OF THE EVENT BEGINNING DURING                     AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY)                   (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN                    12Z SUN AND THE FORECAST HOUR (CUMULATIVE PROBABILITY)        PROBABILITIES ARE GIVEN IN PERCENT                                   X INDICATES PROBABILITIES LESS THAN 1 PERCENT                        PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT.              PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY               64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT.                      - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - -                    FROM    FROM    FROM    FROM    FROM    FROM    FROM    TIME       12Z SUN 00Z MON 12Z MON 00Z TUE 12Z TUE 12Z WED 12Z THU PERIODS         TO      TO      TO      TO      TO      TO      TO                00Z MON 12Z MON 00Z TUE 12Z TUE 12Z WED 12Z THU 12Z FRI  FORECAST HOUR    (12)   (24)    (36)    (48)    (72)    (96)   (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  LOCATION       KT                                                     $$                                                                   FORECASTER PAPIN                                                     

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Summary for Post-Tropical Cyclone Wanda (AT1/AL212021)

  000 WTNT31 KNHC 071445 TCPAT1  BULLETIN Post-Tropical Cyclone Wanda Advisory Number  31 NWS National Hurricane Center Miami FL       AL212021 300 PM GMT Sun Nov 07 2021  ...WANDA BECOMES A POST-TROPICAL CYCLONE... ...THIS IS THE FINAL ADVISORY...   SUMMARY OF 300 PM GMT...1500 UTC...INFORMATION ---------------------------------------------- LOCATION...40.2N 33.5W ABOUT 380 MI...610 KM WNW OF THE AZORES MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...NE OR 45 DEGREES AT 25 MPH...41 KM/H MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES   WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect.   DISCUSSION AND OUTLOOK ---------------------- At 300 PM GMT (1500 UTC), the center of Post-Tropical Cyclone Wanda was located near latitude 40.2 North, longitude 33.5 West. The post-tropical cyclone is moving toward the northeast near 25 mph  (41 km/h) and this motion is expected to continue with further  acceleration through Monday.  Maximum sustained winds are near 40 mph (65 km/h) with higher gusts.  The post-tropical cyclone is forecast to merge with a frontal system  tonight and dissipate by Monday.   Gale-force 34-kt winds extend outward up to 70 miles (110 km) from  the center.  The estimated minimum central pressure is 1003 mb (29.62 inches).   HAZARDS AFFECTING LAND ---------------------- None.   NEXT ADVISORY ------------- This is the last public advisory issued by the National Hurricane Center on Wanda. Additional information on this system can be found  in High Seas Forecasts issued by Meteo France under WMO header  FQNT50 LFPW and available on the web at www.meteofrance.com/previsions-meteo-marine/bulletin/grandlarge/ metarea2.  $$ Forecaster Papin  

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Post-Tropical Cyclone Wanda Forecast Advisory Number 31

  043  WTNT21 KNHC 071444 TCMAT1  POST-TROPICAL CYCLONE WANDA FORECAST/ADVISORY NUMBER  31 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL212021 1500 UTC SUN NOV 07 2021  THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.  POST-TROPICAL CYCLONE CENTER LOCATED NEAR 40.2N  33.5W AT 07/1500Z POSITION ACCURATE WITHIN  30 NM  PRESENT MOVEMENT TOWARD THE NORTHEAST OR  45 DEGREES AT  22 KT  ESTIMATED MINIMUM CENTRAL PRESSURE 1003 MB MAX SUSTAINED WINDS  35 KT WITH GUSTS TO  45 KT. 34 KT.......  0NE  60SE   0SW   0NW. 12 FT SEAS.. 80NE 120SE  90SW  60NW. 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 40.2N  33.5W AT 07/1500Z AT 07/1200Z CENTER WAS LOCATED NEAR 39.2N  34.9W  FORECAST VALID 08/0000Z 43.5N  29.1W...POST-TROP/EXTRATROP MAX WIND  35 KT...GUSTS  45 KT. 34 KT...  0NE  80SE   0SW   0NW.  FORECAST VALID 08/1200Z...DISSIPATED  REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 40.2N  33.5W  THIS IS THE LAST FORECAST/ADVISORY ISSUED BY THE NATIONAL HURRICANE  CENTER ON WANDA.  ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE  FOUND IN HIGH SEAS FORECASTS ISSUED BY METEO FRANCE...UNDER WMO  HEADER FQNT50 LFPW.  $$ FORECASTER PAPIN    

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Tropical Storm Wanda Forecast Discussion Number 30

  000 WTNT41 KNHC 070841 TCDAT1  Tropical Storm Wanda Discussion Number  30 NWS National Hurricane Center Miami FL       AL212021 900 AM GMT Sun Nov 07 2021  Wanda is barely hanging on as a sheared tropical storm due to a  small burst of deep convection located in the southeastern quadrant.  The initial intensity has been maintained at 35 kt based on earlier  30-kt ASCAT data being co-located with the new burst of deep  convection. Little or no change in strength is expected during the  next 36 hours due to southwesterly vertical wind shear increasing to  more than 40 kt by 18-24 hours, and sea-surface temperatures  decreasing to less than 20 deg C beneath the cyclone. In the 18-24-h  period, Wanda is expected to merge with a rapidly approaching cold  front currently located to its west, becoming extratropical tonight  and dissipating over the far northeastern Atlantic on Monday.  The initial motion estimate is now 050/15 kt. There are no  significant changes to the previous forecast track and rationale.  During the next 24 hours or so, Wanda is expected to continue   accelerating northeastward ahead of a strong deep-layer trough and  associated cold front. After merging with the front system, the  extratropical low should maintain a fast northeastward motion until  it dissipates by 48 hours. The new NHC forecast track is very  similar to the previous advisory track, and lies close to the  tightly packed consensus track models.   FORECAST POSITIONS AND MAX WINDS  INIT  07/0900Z 38.5N  35.5W   35 KT  40 MPH  12H  07/1800Z 41.6N  31.7W   35 KT  40 MPH  24H  08/0600Z 46.6N  24.6W   35 KT  40 MPH...POST-TROP/EXTRATROP  36H  08/1800Z 51.1N  17.1W   35 KT  40 MPH...POST-TROP/EXTRATROP  48H  09/0600Z...DISSIPATED  $$ Forecaster Stewart  

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Tropical Storm Wanda Graphics


Coastal Watches/Warnings and Forecast Cone for Storm Center

Forecast Length* Forecast Track Line Initial Wind Field






cone graphic

* If the storm is forecast to dissipate within 3 days, the “Full Forecast” and “3 day” graphic will be identical

Click Here for a 5-day Cone Printer Friendly Graphic

How to use the cone graphic (video):

Link to video describing cone graphic

About this product:

This graphic shows an approximate representation of coastal areas under a hurricane warning (red), hurricane watch (pink), tropical storm warning (blue) and tropical storm watch (yellow). The orange circle indicates the current position of the center of the tropical cyclone. The black line, when selected, and dots show the National Hurricane Center (NHC) forecast track of the center at the times indicated. The dot indicating the forecast center location will be black if the cyclone is forecast to be tropical and will be white with a black outline if the cyclone is forecast to be extratropical. If only an L is displayed, then the system is forecast to be a remnant low. The letter inside the dot indicates the NHC’s forecast intensity for that time:

D: Tropical Depression – wind speed less than 39 MPH

S: Tropical Storm – wind speed between 39 MPH and 73 MPH

H: Hurricane – wind speed between 74 MPH and 110 MPH

M: Major Hurricane – wind speed greater than 110 MPH

NHC tropical cyclone forecast tracks can be in error. This forecast uncertainty is conveyed by the track forecast “cone”, the solid white and stippled white areas in the graphic. The solid white area depicts the track forecast uncertainty for days 1-3 of the forecast, while the stippled area depicts the uncertainty on days 4-5. Historical data indicate that the entire 5-day path of the center of the tropical cyclone will remain within the cone about 60-70% of the time. To form the cone, a set of imaginary circles are placed along the forecast track at the 12, 24, 36, 48, 72, 96, and 120 h positions, where the size of each circle is set so that it encloses 67% of the previous five years official forecast errors. The cone is then formed by smoothly connecting the area swept out by the set of circles.

It is also important to realize that a tropical cyclone is not a point. Their effects can span many hundreds of miles from the center. The area experiencing hurricane force (one-minute average wind speeds of at least 74 mph) and tropical storm force (one-minute average wind speeds of 39-73 mph) winds can extend well beyond the white areas shown enclosing the most likely track area of the center. The distribution of hurricane and tropical storm force winds in this tropical cyclone can be seen in the Wind History graphic linked above.

Considering the combined forecast uncertainties in track, intensity, and size, the chances that any particular location will experience winds of 34 kt (tropical storm force), 50 kt, or 64 kt (hurricane force) from this tropical cyclone are presented in tabular form for selected locations and forecast positions. This information is also presented in graphical form for the 34 kt, 50 kt, and 64 kt thresholds.

Note:  A detailed definition of the NHC track forecast cone is also available.

Read More

Tropical Storm Wanda Graphics


Coastal Watches/Warnings and Forecast Cone for Storm Center

Forecast Length* Forecast Track Line Initial Wind Field






cone graphic

* If the storm is forecast to dissipate within 3 days, the “Full Forecast” and “3 day” graphic will be identical

Click Here for a 5-day Cone Printer Friendly Graphic

How to use the cone graphic (video):

Link to video describing cone graphic

About this product:

This graphic shows an approximate representation of coastal areas under a hurricane warning (red), hurricane watch (pink), tropical storm warning (blue) and tropical storm watch (yellow). The orange circle indicates the current position of the center of the tropical cyclone. The black line, when selected, and dots show the National Hurricane Center (NHC) forecast track of the center at the times indicated. The dot indicating the forecast center location will be black if the cyclone is forecast to be tropical and will be white with a black outline if the cyclone is forecast to be extratropical. If only an L is displayed, then the system is forecast to be a remnant low. The letter inside the dot indicates the NHC’s forecast intensity for that time:

D: Tropical Depression – wind speed less than 39 MPH

S: Tropical Storm – wind speed between 39 MPH and 73 MPH

H: Hurricane – wind speed between 74 MPH and 110 MPH

M: Major Hurricane – wind speed greater than 110 MPH

NHC tropical cyclone forecast tracks can be in error. This forecast uncertainty is conveyed by the track forecast “cone”, the solid white and stippled white areas in the graphic. The solid white area depicts the track forecast uncertainty for days 1-3 of the forecast, while the stippled area depicts the uncertainty on days 4-5. Historical data indicate that the entire 5-day path of the center of the tropical cyclone will remain within the cone about 60-70% of the time. To form the cone, a set of imaginary circles are placed along the forecast track at the 12, 24, 36, 48, 72, 96, and 120 h positions, where the size of each circle is set so that it encloses 67% of the previous five years official forecast errors. The cone is then formed by smoothly connecting the area swept out by the set of circles.

It is also important to realize that a tropical cyclone is not a point. Their effects can span many hundreds of miles from the center. The area experiencing hurricane force (one-minute average wind speeds of at least 74 mph) and tropical storm force (one-minute average wind speeds of 39-73 mph) winds can extend well beyond the white areas shown enclosing the most likely track area of the center. The distribution of hurricane and tropical storm force winds in this tropical cyclone can be seen in the Wind History graphic linked above.

Considering the combined forecast uncertainties in track, intensity, and size, the chances that any particular location will experience winds of 34 kt (tropical storm force), 50 kt, or 64 kt (hurricane force) from this tropical cyclone are presented in tabular form for selected locations and forecast positions. This information is also presented in graphical form for the 34 kt, 50 kt, and 64 kt thresholds.

Note:  A detailed definition of the NHC track forecast cone is also available.

Read More

Tropical Storm Wanda Forecast Discussion Number 29

  786  WTNT41 KNHC 070241 TCDAT1  Tropical Storm Wanda Discussion Number  29 NWS National Hurricane Center Miami FL       AL212021 300 AM GMT Sun Nov 07 2021  Wanda has continued to weaken tonight. Only small bursts of  convection have occurred during the past several hours, and Wanda's  low-level center is starting to move away from the ongoing  convection in its southeastern quadrant. A 2220 UTC ASCAT-A pass  revealed a small area of 30-kt winds in this portion of the cyclone,  but the infrared cloud top temperatures have cooled in this area  since that data was collected. The initial intensity is lowered to  35 kt for this advisory, which lies on the higher end of the most  recent satellite estimates.  Wanda is beginning to move faster toward the northeast, and its  initial motion is estimated to be 050/12 kt. The cyclone will  continue to accelerate northeastward over the next day or so within  the strengthening, deep-layer southwesterly flow associated with a  deepening mid-latitude low pressure system over the northern  Atlantic. The track guidance remains tightly clustered, and the  latest NHC track forecast is virtually unchanged from the previous  advisory.  Environmental conditions are forecast to become increasingly  unfavorable for any further tropical development of Wanda. As the  cyclone races northeastward, it will encounter decreasing SSTs and  increasing deep-layer southerly shear within a dry mid-level  environment. Thus, Wanda's convective structure is unlikely to  improve over the next 24 h. The intensity guidance suggests the peak  winds could increase slightly later today, but this is most likely a  product of the system's increasing forward speed and its merger with  an approaching front. Thus, the official NHC intensity forecast has  been lowered from the previous one.  Wanda is still forecast to  merge with the front and become extratropical tonight, then  dissipate over the northeastern Atlantic on Monday.   FORECAST POSITIONS AND MAX WINDS  INIT  07/0300Z 37.8N  36.8W   35 KT  40 MPH  12H  07/1200Z 39.8N  34.1W   35 KT  40 MPH  24H  08/0000Z 44.4N  28.3W   40 KT  45 MPH...POST-TROP/EXTRATROP  36H  08/1200Z 48.9N  21.5W   35 KT  40 MPH...POST-TROP/EXTRATROP  48H  09/0000Z...DISSIPATED  $$ Forecaster Reinhart   

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Tropical Storm Wanda Graphics


Coastal Watches/Warnings and Forecast Cone for Storm Center

Forecast Length* Forecast Track Line Initial Wind Field






cone graphic

* If the storm is forecast to dissipate within 3 days, the “Full Forecast” and “3 day” graphic will be identical

Click Here for a 5-day Cone Printer Friendly Graphic

How to use the cone graphic (video):

Link to video describing cone graphic

About this product:

This graphic shows an approximate representation of coastal areas under a hurricane warning (red), hurricane watch (pink), tropical storm warning (blue) and tropical storm watch (yellow). The orange circle indicates the current position of the center of the tropical cyclone. The black line, when selected, and dots show the National Hurricane Center (NHC) forecast track of the center at the times indicated. The dot indicating the forecast center location will be black if the cyclone is forecast to be tropical and will be white with a black outline if the cyclone is forecast to be extratropical. If only an L is displayed, then the system is forecast to be a remnant low. The letter inside the dot indicates the NHC’s forecast intensity for that time:

D: Tropical Depression – wind speed less than 39 MPH

S: Tropical Storm – wind speed between 39 MPH and 73 MPH

H: Hurricane – wind speed between 74 MPH and 110 MPH

M: Major Hurricane – wind speed greater than 110 MPH

NHC tropical cyclone forecast tracks can be in error. This forecast uncertainty is conveyed by the track forecast “cone”, the solid white and stippled white areas in the graphic. The solid white area depicts the track forecast uncertainty for days 1-3 of the forecast, while the stippled area depicts the uncertainty on days 4-5. Historical data indicate that the entire 5-day path of the center of the tropical cyclone will remain within the cone about 60-70% of the time. To form the cone, a set of imaginary circles are placed along the forecast track at the 12, 24, 36, 48, 72, 96, and 120 h positions, where the size of each circle is set so that it encloses 67% of the previous five years official forecast errors. The cone is then formed by smoothly connecting the area swept out by the set of circles.

It is also important to realize that a tropical cyclone is not a point. Their effects can span many hundreds of miles from the center. The area experiencing hurricane force (one-minute average wind speeds of at least 74 mph) and tropical storm force (one-minute average wind speeds of 39-73 mph) winds can extend well beyond the white areas shown enclosing the most likely track area of the center. The distribution of hurricane and tropical storm force winds in this tropical cyclone can be seen in the Wind History graphic linked above.

Considering the combined forecast uncertainties in track, intensity, and size, the chances that any particular location will experience winds of 34 kt (tropical storm force), 50 kt, or 64 kt (hurricane force) from this tropical cyclone are presented in tabular form for selected locations and forecast positions. This information is also presented in graphical form for the 34 kt, 50 kt, and 64 kt thresholds.

Note:  A detailed definition of the NHC track forecast cone is also available.

Read More