Post-tropical Cyclone Gert

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Public Advisory:

Post-Tropical Cyclone Gert Advisory Number  20
NWS National Hurricane Center Miami FL       AL082017
500 PM AST Thu Aug 17 2017

...GERT BECOMES A POST-TROPICAL CYCLONE...
...THIS IS THE LAST ADVISORY...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...44.8N 46.0W
ABOUT 860 MI...1390 KM E OF HALIFAX NOVA SCOTIA
ABOUT 365 MI...590 KM ESE OF CAPE RACE NEWFOUNDLAND
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...ENE OR 60 DEGREES AT 39 MPH...63 KM/H
MINIMUM CENTRAL PRESSURE...985 MB...29.09 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
At 500 PM AST (2100 UTC), the center of Post-Tropical Cyclone Gert
was located near latitude 44.8 North, longitude 46.0 West.  The
post-tropical cyclone is moving toward the east-northeast near 39
mph (63 km/h).  Gert should move quickly toward the northeast for a
day or so, before slowing and merging with another low pressure
system over the weekend.

Maximum sustained winds have decreased to near 65 mph (100 km/h)
with higher gusts.  Additional weakening is forecast during the
next 36 to 48 hours.

Tropical-storm-force winds extend outward up to 230 miles (370 km)
from the center.

The estimated minimum central pressure is 985 mb (29.09 inches).


HAZARDS AFFECTING LAND
----------------------
SURF:  Swells generated by Gert will continue to affect the coast
of the northeastern United States and Atlantic Canada through
tonight.  These swells are likely to cause life-threatening surf and
rip current conditions.  Please consult products from your local
weather forecast office.


NEXT ADVISORY
-------------
This is the last public advisory issued by the National Hurricane
Center on this system.  Additional information on this system can be
found in High Seas Forecasts issued by the National Weather Service,
under AWIPS header NFDHSFAT1, WMO header FZNT01 KWBC, and available
on the Web at http://www.opc.ncep.noaa.gov/shtml/NFDHSFAT1.shtml.

$$
Forecaster Zelinsky



Discussion:
TCDAT3  
  
Post-Tropical Cyclone Gert Discussion Number  20  
NWS National Hurricane Center Miami FL       AL082017  
500 PM AST Thu Aug 17 2017  
  
Gert is now post-tropical.  The circulation has become quite  
elongated, and the remaining deep convection appears to be primarily  
associated with frontal boundaries.  A pair of late-arriving ASCAT  
passes from around 1300 and 1400 UTC indicated that Gert was weaker  
than previously estimated.  Based on the ASCAT data, the initial  
intensity has been lowered to 55 kt.  The initial wind radii were  
also adjusted based on the ASCAT data.  
  
The initial motion estimate is a brisk 060/34 kt.  Gert should  
move quickly northeastward for the next 12 to 24 h while  
gradually spinning down.  After that time, it should slow down and  
turn more toward the north while merging with or being absorbed by  
another extratropical low.  The track, intensity, and wind radii  
forecasts have incorporated guidance from NOAA's Ocean Prediction  
Center.  
  
Swells from Gert should continue to affect the coast of the  
northeastern U.S. and Atlantic Canada through tonight.  These swells  
are likely to produce dangerous surf and rip current conditions.  
Please consult products from your local weather forecast office for  
more information.  
  
This is the last NHC advisory on Gert.  Additional information on  
this system can be found in High Seas Forecasts issued by the  
National Weather Service, under AWIPS header NFDHSFAT1, WMO header  
FZNT01 KWBC, and available on the Web at  
http://www.opc.ncep.noaa.gov/shtml/NFDHSFAT1.shtml.  
  
FORECAST POSITIONS AND MAX WINDS  
  
INIT  17/2100Z 44.8N  46.0W   55 KT  65 MPH  TS...POST-TROPICAL
 12H  18/0600Z 47.8N  40.5W   45 KT  50 MPH  TS...POST-TROP/EXTRATROP
 24H  18/1800Z 50.6N  36.2W   40 KT  45 MPH  TS...POST-TROP/EXTRATROP
 36H  19/0600Z 52.5N  35.0W   35 KT  40 MPH  TS...POST-TROP/EXTRATROP
 48H  19/1800Z...DISSIPATED  
  
$$  
Forecaster Zelinsky
Note: Storm classification added by stormcarib.com
TD=TROPICAL DEPRESSION; TS=TROPICAL STORM; CAT-1=CATEGORY-1 HURRICANE...


Wind Speed:
PWSAT3
                                                                    
POST-TROPICAL CYCLONE GERT WIND SPEED PROBABILITIES NUMBER  20      
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL082017               
2100 UTC THU AUG 17 2017                                            
                                                                    
AT 2100Z THE CENTER OF POST-TROPICAL CYCLONE GERT WAS LOCATED NEAR  
LATITUDE 44.8 NORTH...LONGITUDE 46.0 WEST WITH MAXIMUM SUSTAINED    
WINDS NEAR 55 KTS...65 MPH...100 KM/H.                              
                                                                    
Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH)                  
   ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME      
   EASTERN  DAYLIGHT TIME (EDT)...SUBTRACT 4 HOURS FROM Z TIME      
   CENTRAL  DAYLIGHT TIME (CDT)...SUBTRACT 5 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           
        18Z THU 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       18Z THU 06Z FRI 18Z FRI 06Z SAT 18Z SAT 18Z SUN 18Z MON
PERIODS         TO      TO      TO      TO      TO      TO      TO  
             06Z FRI 18Z FRI 06Z SAT 18Z SAT 18Z SUN 18Z MON 18Z TUE
                                                                    
FORECAST HOUR    (12)   (24)    (36)    (48)    (72)    (96)   (120)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
LOCATION       KT                                                   
                                                                    
$$                                                                  
FORECASTER ZELINSKY                                                 


Forecast/Advisory:

POST-TROPICAL CYCLONE GERT FORECAST/ADVISORY NUMBER  20
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL082017
2100 UTC THU AUG 17 2017

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

POST-TROPICAL CYCLONE CENTER LOCATED NEAR 44.8N  46.0W AT 17/2100Z
POSITION ACCURATE WITHIN  25 NM

PRESENT MOVEMENT TOWARD THE EAST-NORTHEAST OR  60 DEGREES AT  34 KT

ESTIMATED MINIMUM CENTRAL PRESSURE  985 MB
MAX SUSTAINED WINDS  55 KT WITH GUSTS TO  65 KT.
50 KT....... 40NE  60SE   0SW   0NW.
34 KT.......120NE 200SE 120SW  20NW.
12 FT SEAS..180NE 120SE 660SW  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 44.8N  46.0W AT 17/2100Z
AT 17/1800Z CENTER WAS LOCATED NEAR 44.0N  48.0W

FORECAST VALID 18/0600Z 47.8N  40.5W...POST-TROP/EXTRATROP
MAX WIND  45 KT...GUSTS  55 KT.
34 KT...180NE 240SE 120SW  90NW.

FORECAST VALID 18/1800Z 50.6N  36.2W...POST-TROP/EXTRATROP
MAX WIND  40 KT...GUSTS  50 KT.
34 KT...180NE 180SE 120SW 120NW.

FORECAST VALID 19/0600Z 52.5N  35.0W...POST-TROP/EXTRATROP
MAX WIND  35 KT...GUSTS  45 KT.
34 KT...210NE 120SE  60SW 150NW.

FORECAST VALID 19/1800Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 44.8N  46.0W

THIS IS THE LAST FORECAST/ADVISORY ISSUED BY THE NATIONAL HURRICANE
CENTER ON THIS SYSTEM.  ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE
FOUND IN HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER
SERVICE...UNDER AWIPS HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.


$$
FORECASTER ZELINSKY


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