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Current Tropical Discussion For Pacific Basin

Eastern North Pacific Tropical Weather Outlook


000
ABPZ20 KNHC 241114
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Thu Sep 24 2020

For the eastern North Pacific...east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Tropical
Storm Lowell, located nearly 1000 miles west of the southern tip of
the Baja California peninsula.

An area of low pressure is expected to form south or southwest of
the southwest coast of Mexico next week. Some gradual development
will be possible thereafter while the system moves generally
west-northwestward.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

$$
Forecaster Zelinsky

Summary for Tropical Storm Lowell (EP2/EP172020)

...LOWELL GRADUALLY MOVING OVER COOLER WATERS...
 As of 11:00 PM HST Wed Sep 23
 the center of Lowell was located near 21.2, -123.7
 with movement WNW at 10 mph.
 The minimum central pressure was 1003 mb
 with maximum sustained winds of about 45 mph.

Tropical Storm Lowell Public Advisory Number 15

Issued at 1100 PM HST Wed Sep 23 2020  

000
WTPZ32 KNHC 240837
TCPEP2
 
BULLETIN
Tropical Storm Lowell Advisory Number  15
NWS National Hurricane Center Miami FL       EP172020
1100 PM HST Wed Sep 23 2020
 
...LOWELL GRADUALLY MOVING OVER COOLER WATERS...
 
 
SUMMARY OF 1100 PM HST...0900 UTC...INFORMATION
-----------------------------------------------
LOCATION...21.2N 123.7W
ABOUT 890 MI...1435 KM W OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 10 MPH...17 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 1100 PM HST (0900 UTC), the center of Tropical Storm Lowell was
located near latitude 21.2 North, longitude 123.7 West. Lowell is
moving toward the west-northwest near 10 mph (17 km/h).  A turn 
toward the west is expected Thursday morning, with that heading and 
a gradual increase in forward speed continuing through early next 
week.
 
Maximum sustained winds are near 45 mph (75 km/h) with higher gusts.
Gradual weakening is forecast to begin by late Thursday.  Lowell is 
expected to weaken to a tropical depression by late Friday and 
become a remnant low by early Saturday.
 
Tropical-storm-force winds extend outward up to 90 miles (150 km)
from the center.
 
The estimated minimum central pressure is 1003 mb (29.62 inches).
 
 
HAZARDS AFFECTING LAND
----------------------
None.
 
 
NEXT ADVISORY
-------------
Next complete advisory at 500 AM HST.
 
$$
Forecaster Berg
 

Tropical Storm Lowell Forecast Advisory Number 15

Issued at 0900 UTC THU SEP 24 2020  

000
WTPZ22 KNHC 240837
TCMEP2
 
TROPICAL STORM LOWELL FORECAST/ADVISORY NUMBER  15
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP172020
0900 UTC THU SEP 24 2020
 
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.
 
TROPICAL STORM CENTER LOCATED NEAR 21.2N 123.7W AT 24/0900Z
POSITION ACCURATE WITHIN  25 NM
 
PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT   9 KT
 
ESTIMATED MINIMUM CENTRAL PRESSURE 1003 MB
MAX SUSTAINED WINDS  40 KT WITH GUSTS TO  50 KT.
34 KT....... 80NE  80SE   0SW   0NW.
12 FT SEAS..120NE  60SE  60SW 120NW.
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 21.2N 123.7W AT 24/0900Z
AT 24/0600Z CENTER WAS LOCATED NEAR 21.1N 123.2W
 
FORECAST VALID 24/1800Z 21.4N 125.1W
MAX WIND  40 KT...GUSTS  50 KT.
34 KT... 70NE  60SE   0SW  30NW.
 
FORECAST VALID 25/0600Z 21.7N 127.3W
MAX WIND  35 KT...GUSTS  45 KT.
34 KT... 60NE  40SE   0SW  50NW.
 
FORECAST VALID 25/1800Z 21.6N 129.6W
MAX WIND  35 KT...GUSTS  45 KT.
34 KT... 60NE   0SE   0SW  60NW.
 
FORECAST VALID 26/0600Z 21.5N 132.1W
MAX WIND  30 KT...GUSTS  40 KT.
 
FORECAST VALID 26/1800Z 21.3N 134.7W...POST-TROP/REMNT LOW
MAX WIND  30 KT...GUSTS  40 KT.
 
FORECAST VALID 27/0600Z 21.2N 137.4W...POST-TROP/REMNT LOW
MAX WIND  25 KT...GUSTS  35 KT.
 
EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 100 NM
ON DAY 4 AND 150 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY
 
OUTLOOK VALID 28/0600Z 21.2N 142.7W...POST-TROP/REMNT LOW
MAX WIND  25 KT...GUSTS  35 KT.
 
OUTLOOK VALID 29/0600Z 21.7N 146.9W...POST-TROP/REMNT LOW
MAX WIND  20 KT...GUSTS  30 KT.
 
REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 21.2N 123.7W
 
NEXT ADVISORY AT 24/1500Z
 
$$
FORECASTER BERG
 
 

Tropical Storm Lowell Forecast Discussion Number 15

Issued at 1100 PM HST Wed Sep 23 2020  

000
WTPZ42 KNHC 240838
TCDEP2
 
Tropical Storm Lowell Discussion Number  15
NWS National Hurricane Center Miami FL       EP172020
1100 PM HST Wed Sep 23 2020
 
Lowell is maintaining status quo, with a few bands of deep 
convection located 30 n mi or more to the east of the exposed 
center.  A recent ASCAT-C pass just clipped the eastern edge of the 
tropical-storm-force wind field and had vectors as high as 36 to 37 
kt, so it is assumed that Lowell's intensity is still 40 kt.

The available shear analyses indicate that the deep-layer shear 
over Lowell is low--maybe slightly moderate--but this seems odd 
given the cyclone's sheared appearance.  Regardless of what the 
shear is now, the relative shear magnitude is expected to begin 
increasing in about 36 hours as Lowell moves closer to an 
upper-level jet stream.  The storm will also be moving over 
gradually decreasing sea surface temperatures and into a much drier 
air mass, and all of these factors should conspire to cause 
weakening over the next several days.  Global model guidance 
indicates that Lowell should lose its deep convection and become a 
remnant low by 60 hours, although the ECMWF suggests this could 
happen as early as in a day or two.

Lowell has been locked into a west-northwestward motion of 285/9 
kt, but the track models insist that it should turn toward the 
west very soon as the subtropical ridge to its north strengthens.  
The ridge is forecast to remain anchored north of Lowell for the 
entire forecast period, causing a gradual acceleration toward the 
west or even just south of due west into early next week.  The 
earlier-noted speed differences among some of the models appear to 
have resolved themselves a bit, although the models overall have 
sped up.  In response, the new NHC track forecast is faster than 
the previous prediction, and yet it is still not as fast as the 
TVCE multi-model consensus aid or the HCCA model.  This probably 
means that additional adjustments to forecast speeds are likely in 
subsequent advisories.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0900Z 21.2N 123.7W   40 KT  45 MPH
 12H  24/1800Z 21.4N 125.1W   40 KT  45 MPH
 24H  25/0600Z 21.7N 127.3W   35 KT  40 MPH
 36H  25/1800Z 21.6N 129.6W   35 KT  40 MPH
 48H  26/0600Z 21.5N 132.1W   30 KT  35 MPH
 60H  26/1800Z 21.3N 134.7W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  27/0600Z 21.2N 137.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  28/0600Z 21.2N 142.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  29/0600Z 21.7N 146.9W   20 KT  25 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Berg
 

Tropical Storm Lowell Wind Speed Probabilities Number 15

Issued at 0900 UTC THU SEP 24 2020


000
FOPZ12 KNHC 240837
PWSEP2
                                                                    
TROPICAL STORM LOWELL WIND SPEED PROBABILITIES NUMBER  15           
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP172020               
0900 UTC THU SEP 24 2020                                            
                                                                    
AT 0900Z THE CENTER OF TROPICAL STORM LOWELL WAS LOCATED NEAR       
LATITUDE 21.2 NORTH...LONGITUDE 123.7 WEST WITH MAXIMUM SUSTAINED   
WINDS NEAR 40 KTS...45 MPH...75 KM/H.                               
                                                                    
Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH)                  
   PACIFIC  DAYLIGHT TIME (PDT)...SUBTRACT 7 HOURS FROM Z TIME      
   HAWAIIAN STANDARD TIME (HST)...SUBTRACT 10 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           
        06Z 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       06Z THU 18Z THU 06Z FRI 18Z FRI 06Z SAT 06Z SUN 06Z MON
PERIODS         TO      TO      TO      TO      TO      TO      TO  
             18Z THU 06Z FRI 18Z FRI 06Z SAT 06Z SUN 06Z MON 06Z TUE
                                                                    
FORECAST HOUR    (12)   (24)    (36)    (48)    (72)    (96)   (120)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
LOCATION       KT                                                   
                                                                    
20N 125W       34 10   2(12)   X(12)   X(12)   X(12)   X(12)   X(12)
 
20N 130W       34  X   1( 1)   5( 6)   6(12)   1(13)   X(13)   X(13)
 
20N 135W       34  X   X( X)   X( X)   1( 1)  10(11)   X(11)   X(11)
 
20N 140W       34  X   X( X)   X( X)   X( X)   1( 1)   6( 7)   1( 8)
 
20N 145W       34  X   X( X)   X( X)   X( X)   X( X)   2( 2)   1( 3)
 
$$                                                                  
FORECASTER BERG                                                     

Tropical Storm Lowell Graphics


Tropical Storm Lowell 5-Day Uncertainty Track Image
5-Day Uncertainty Track last updated Thu, 24 Sep 2020 08:40:21 GMT

Tropical Storm Lowell 34-Knot Wind Speed Probabilities
Wind Speed Probabilities last updated Thu, 24 Sep 2020 09:32:43 GMT