Tropical Storm Barbara

Post-Tropical Storm Barbara Track 0500 Hours July 6 2019
Post-Tropical Storm Barbara Track 0500 Hours July 6 2019
Hurricane Barbara Satellite 0500 Hours July 5 2019
Hurricane Barbara Satellite 0500 Hours July 5, 2019

Hurricane Barbara –  NWS National Hurricane Center Miami FL 500 AM HST Sat Jul 06 2019

The combination of cold sea surface temperatures and strong westerly shear has taken a toll on Barbara. The system has degenerated significantly, and it now consists of a vigorous swirl of low clouds devoid of any deep convection. Consequently, it no longer classifies as a tropical cyclone, and this is the last advisory.

The winds are estimated to be near 35 kt with higher gusts. Additional weakening is indicated, and the system should dissipate in a couple of days while it moves toward the west steered by the low-level trade winds.


FORECAST POSITIONS AND MAX WINDS

INIT  06/1500Z 18.7N 139.2W   35 KT  40 MPH...POST-TROPICAL - (WSW Hilo, Hawaii)
 12H  07/0000Z 18.6N 141.5W   30 KT  35 MPH...POST-TROP/REMNT LOW - (WSW Hilo, Hawaii)
 24H  07/1200Z 18.4N 144.9W   30 KT  35 MPH...POST-TROP/REMNT LOW - (WSW Hilo, Hawaii)
 36H  08/0000Z 18.0N 148.8W   25 KT  30 MPH...POST-TROP/REMNT LOW - (WSW Hilo, Hawaii)
 48H  08/1200Z 18.0N 152.5W   20 KT  25 MPH...POST-TROP/REMNT LOW - (WSW Hilo, Hawaii)
 72H  09/1200Z...DISSIPATED

NWS National Hurricane Center Miami FL 800 PM HST Fri Jul 5, 2019

For the central North Pacific…between 140W and 180W: The National Hurricane Center in Miami, Florida is issuing advisories on weakening Tropical Storm Barbara, centered about 1200 miles east of Hilo, Hawaii. Based on the latest forecast, Barbara, is expected to cross longitude 140W into the Central Pacific Hurricane Center Area of Responsibility Saturday morning as a post-tropical low.

NWS National Hurricane Center Miami FL EP022019 500 AM HST Fri Jul 05 2019

Strong southwesterly shear and marginal SSTs are causing Barbara to continue to weaken. The associated deep convection, which is displaced to the northeast of the cyclone center, is diminishing in both coverage and intensity. Using a blend of Dvorak Current Intensity and T-numbers from TAFB and SAB results in an advisory intensity estimate of 60 kt. Since the shear is expected to increase further, continued weakening is likely and Barbara should degenerate into a remnant low in 48 hours or sooner. The official intensity forecast is near or above the latest model consensus.

The initial motion estimate is 305/11 kt. A low- to mid-level ridge is forecast to build to the north of Barbara over the next couple of days. As a result, the cyclone should turn toward the west-northwest and west during the next 24 to 48 hours. The official track forecast is similar to the previous one, and very close to the simple and corrected model consensus tracks.

FORECAST POSITIONS AND MAX WINDS

INIT  05/1500Z 18.4N 133.6W   60 KT  70 MPH - Tropical Storm (WSW Hilo, Hawaii)
 12H  06/0000Z 18.8N 135.4W   50 KT  60 MPH - Tropical Storm (WSW Hilo, Hawaii)
 24H  06/1200Z 19.2N 138.1W   40 KT  45 MPH - Tropical Storm (WSW Hilo, Hawaii)
 36H  07/0000Z 19.3N 141.0W   30 KT  35 MPH - Tropical Storm (WSW Hilo, Hawaii)
 48H  07/1200Z 19.1N 144.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  08/1200Z 19.0N 151.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  09/1200Z...DISSIPATED

NWS Central Pacific Hurricane Center Honolulu HI 200 AM HST Fri Jul 5, 2019

For the central North Pacific…between 140W and 180W: The National Hurricane Center in Miami, Florida is issuing advisories on Hurricane Barbara, centered around 1500 miles east of Hilo, Hawaii. Based on the latest forecast, Barbara is expected to cross longitude 140W into the Central Pacific Basin Saturday as a weakening tropical storm.

NWS National Hurricane Center Miami FL 1100 PM HST Thu Jul 04, 2019

Conventional and microwave satellite imagery indicates that Barbara is shearing apart, with the eyewall structure disintegrating and the low-level center located to the south of the remaining deep convection. Recent scatterometer overpasses showed several 65-kt wind vectors near the center, and based on a blend of these data and other satellite intensity estimates the initial intensity is reduced to 70 kt. Increasing southwesterly shear, dry air entrainment, and cool sea surface temperatures along the forecast track should cause continued rapid weakening, and Barbara is forecast to decay to a remnant low late Saturday or Saturday night and weaken to a trough by Monday.

The initial motion is now 305/10. The cyclone should turn west-northwestward later today and westward by Saturday as an easterly flow on the south side of a large low- to mid-level ridge becomes the predominant steering mechanism. There has been little change in the track guidance since the last advisory. Thus, the new forecast track is similar to the previous track and lies near the various consensus models.

FORECAST POSITIONS AND MAX WINDS

INIT  05/0900Z 17.7N 132.6W   70 KT  80 MPH - Category 1 (WSW Hilo, Hawaii)
 12H  05/1800Z 18.4N 134.2W   60 KT  70 MPH - Tropical Storm (WSW Hilo, Hawaii)
 24H  06/0600Z 18.9N 136.8W   45 KT  50 MPH - Tropical Storm (WSW Hilo, Hawaii)
 36H  06/1800Z 19.0N 139.6W   35 KT  40 MPH - Tropical Storm (WSW Hilo, Hawaii)
 48H  07/0600Z 18.9N 142.8W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  08/0600Z 18.5N 150.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  09/0600Z...DISSIPATED

NWS National Hurricane Center Miami FL 500 AM HST Thu Jul 04 2019

Satellite images indicate that Barbara continues to gradually weaken. Convection in the eyewall is becoming less intense, with eye temperatures slowly falling. A consensus of the latest satellite estimates suggests 100 kt as the initial wind speed. The hurricane is entering an environment that will likely promote rapid weakening during the next couple of days. Barbara is forecast to traverse sub-26C waters and encounter increasing southwesterly shear, which would help to mix in drier air from the mid-levels of the atmosphere. Thus, the cyclone should weaken to a tropical storm by 36 hours and degenerate into a post-tropical cyclone around the time it enters the Central Pacific basin. The new NHC prediction is similar to the previous one and is a bit lower than the model consensus.

Barbara has turned northwestward recently and is moving about 310/10 kt. This general path is forecast until tomorrow when a mid-level ridge builds to the north of the cyclone, causing a west-northwestward motion. As Barbara weakens, it should turn westward on Saturday, steered by the low-level flow. Model guidance is in very good agreement on this scenario, and no significant changes were required to the previous forecast. All of the models dissipate the cyclone east of the Hawaiian Islands, although the remnants could move across that area in about 5 days.

FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 16.0N 130.0W  100 KT 115 MPH - Category 3 (WSW Hilo, Hawaii)
 12H  05/0000Z 17.0N 131.2W   85 KT 100 MPH - Category 2 (WSW Hilo, Hawaii)
 24H  05/1200Z 18.1N 133.0W   70 KT  80 MPH - Category 1 (WSW Hilo, Hawaii)
 36H  06/0000Z 18.9N 135.2W   50 KT  60 MPH - Tropical Storm (WSW Hilo, Hawaii)
 48H  06/1200Z 19.2N 137.8W   40 KT  45 MPH - Tropical Storm (WSW Hilo, Hawaii)
 72H  07/1200Z 19.0N 143.8W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  08/1200Z 18.8N 150.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  09/1200Z...DISSIPATED

NWS National Hurricane Center Miami FL 1100 AM HST Wed Jul 03, 2019

Satellite images indicate that Hurricane Barbara has continued to gradually weaken. The eye is not as distinct as it has been during the past 24 hours and the cloud tops surrounding the eye have warmed. Dvorak numbers have continued to fall, and based on an average of the latest objective and subjective numbers, the initial intensity has been adjusted down to 120 kt in this advisory. Barbara’s circulation is beginning to move toward cooler waters so a gradual weakening trend should prevail. Faster weakening is anticipated once the shear increases significantly in about 2 days. In fact, Barbara could lose its deep convection, and thus become post-tropical, around the time it is forecast to cross 140W into the central Pacific basin. This is indicated by most of the intensity guidance.

Barbara is moving toward the west-northwest or 300 degrees at 10 kt. The hurricane has reached the southwestern edge of the subtropical ridge, and this flow pattern should steer Barbara on a northwest track during the next 2 days or so. After that time, a new ridge is forecast to build north of the cyclone, resulting in a turn back toward the west. In addition, since Barbara is forecast to become a weak and shallow cyclone, it will likely become steered westward by the low-level trade winds by Saturday. The NHC forecast is not different from the previous one, and it continues to be in the middle of the guidance envelope and very close to the multi-model consensus TVCE.

FORECAST POSITIONS AND MAX WINDS

INIT  03/2100Z 14.3N 127.5W  120 KT 140 MPH - Category 4 (WSW Hilo, Hawaii)
 12H  04/0600Z 15.1N 128.9W  110 KT 125 MPH - Category 3 (WSW Hilo, Hawaii)
 24H  04/1800Z 16.3N 130.4W  100 KT 115 MPH - Category 3 (WSW Hilo, Hawaii)
 36H  05/0600Z 17.5N 132.0W   80 KT  90 MPH - Category 1 (WSW Hilo, Hawaii)
 48H  05/1800Z 18.5N 134.0W   60 KT  70 MPH - Category 1 (WSW Hilo, Hawaii)
 72H  06/1800Z 19.0N 139.0W   35 KT  40 MPH - Tropical Storm (WSW Hilo, Hawaii)
 96H  07/1800Z 19.0N 145.0W   30 KT  35 MPH...POST-TROPICAL
120H  08/1800Z 18.5N 151.5W   30 KT  35 MPH...POST-TROP/REMNT LOW

NWS Central Pacific Hurricane Center Honolulu HI 800 AM HST Wed Jul 3, 2019

For the central North Pacific…between 140W and 180W:

The National Hurricane Center in Miami, Florida is issuing advisories on Hurricane Barbara, centered about 1890 miles east of Hilo, Hawaii. Barbara is expected to move into the Central Pacific Hurricane Center area of responsibility on Saturday.

Elsewhere, no tropical cyclones are expected during the next 5 days.

NWS National Hurricane Center Miami FL 500 AM HST Wed Jul 03 2019

Hurricane Barbara  – It appears that the weakening process has already begun. The ring of intense convection surrounding the eye has warmed up and consequently, Dvorak numbers have continued to fall. Based on an average of the latest objective and subjective numbers, the initial intensity has been adjusted down to 125 kt in this advisory. Barbara’s circulation is beginning to move toward cooler waters so a gradual weakening trend should prevail, although some minor fluctuations in intensity are possible today. Faster weakening is anticipated once the shear increases significantly in about 2 days. In fact, Barbara could lose its deep convection, and thus become post-tropical, around the time it is forecast to cross 140W into the central Pacific basin. This is indicated by most of the intensity guidance.

Barbara is moving toward the west-northwest or 295 degrees at 9 kt. The hurricane has reached the southwestern edge of the subtropical high that has been steering the cyclone, and this flow pattern should force Barbara to move slowly toward the northwest during the next 2 days or so. After that time, a new ridge is forecast to re-build north of the cyclone, resulting in a more westerly track. In addition, since Barbara is forecast to become a weak shallow cyclone, it will likely become steered by the low-level trade winds. The NHC forecast is not different from the previous one, and it continues to be in the middle of the guidance envelope and basically on top of the multi-model consensus TVCE.

FORECAST POSITIONS AND MAX WINDS

INIT  03/1500Z 13.9N 126.6W  125 KT 145 MPH - Category 4 (WSW Hilo, Hawaii)
 12H  04/0000Z 14.6N 128.0W  115 KT 130 MPH - Category 4 (WSW Hilo, Hawaii)
 24H  04/1200Z 15.7N 129.7W  105 KT 120 MPH - Category 2 (WSW Hilo, Hawaii)
 36H  05/0000Z 16.9N 131.5W   95 KT 110 MPH - Category 2 (WSW Hilo, Hawaii)
 48H  05/1200Z 18.0N 133.2W   80 KT  90 MPH - Category 1 (WSW Hilo, Hawaii)
 72H  06/1200Z 19.0N 138.0W   40 KT  45 MPH - Tropical Storm (WSW Hilo, Hawaii)
 96H  07/1200Z 19.0N 144.0W   35 KT  40 MPH...POST-TROPICAL
120H  08/1200Z 18.5N 150.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

NWS Central Pacific Hurricane Center Honolulu HI 200 AM HST Wed Jul 3, 2019

For the central North Pacific…between 140W and 180W:

The National Hurricane Center in Miami, Florida is issuing advisories on Hurricane Barbara, centered about 1960 miles east of Hilo, Hawaii. Barbara is expected to move into the Central Pacific Hurricane Center area of responsibility on Saturday.

NWS National Hurricane Center Miami FL 1100 PM HST Tue Jul 02 2019

Barbara appears to have reached its peak intensity. The solid white ring that had surrounded the eye in the Dvorak enhancement at the time of the previous advisory has eroded, and the eye is not quite as warm. Although Dvorak T-numbers have fallen as a result, Barbara’s winds would likely take some time to respond, and the initial intensity is held at 135 kt as a blend of subjective and objective Dvorak CI numbers.

There are a couple of factors, internal and external, that should lead to gradual weakening in the short term. First, the layer of warm water at the ocean’s surface ahead of Barbara is becoming shallower, with oceanic heat content values falling to zero in the next 48 hours. Second, a very recent GPM microwave overpass suggests that Barbara is developing a concentric eyewall structure, which tends to precede an eyewall replacement and associated weakening. Once weakening is underway due to these circumstances, deep-layer southwesterly shear is then expected to increase over 20 kt from 48 hours and beyond. The intensity models on this cycle are suggesting that Barbara’s weakening rate could be a little faster than shown previously after 48 hours, and this is reflected in the new NHC official forecast, which lies close to the HCCA model and the intensity consensus. Barbara could lose its deep convection, and thus become post tropical, around the time it is forecast to cross 140W into the central Pacific basin.

Barbara continues to move west-northwestward, or 285/12 kt, along the southwestern periphery of the subtropical ridge. There has been no change in the track forecast reasoning, with the hurricane expected to turn northwestward and slow down during the next 36 hours as it approaches a large break in the ridge near and east of the Hawaiian Islands. Once Barbara weakens and becomes a shallower system, it should then turn back to the west and accelerate on days 3 through 5. The new NHC forecast has been adjusted slightly southward for much of the forecast period in order to fall closer to the model consensus solutions.

FORECAST POSITIONS AND MAX WINDS

INIT  03/0900Z 13.5N 125.6W  135 KT 155 MPH - Category 4 (WSW Hilo, Hawaii)
 12H  03/1800Z 14.1N 127.0W  125 KT 145 MPH - Category 4 (WSW Hilo, Hawaii)
 24H  04/0600Z 15.1N 128.8W  115 KT 130 MPH - Category 4 (WSW Hilo, Hawaii)
 36H  04/1800Z 16.3N 130.5W  100 KT 115 MPH - Category 3 (WSW Hilo, Hawaii)
 48H  05/0600Z 17.4N 132.3W   85 KT 100 MPH - Category 2 (WSW Hilo, Hawaii)
 72H  06/0600Z 18.9N 136.4W   50 KT  60 MPH - Tropical Storm (WSW Hilo, Hawaii)
 96H  07/0600Z 19.0N 142.0W   35 KT  40 MPH...POST-TROPICAL
120H  08/0600Z 18.5N 149.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

NWS National Hurricane Center Miami FL 1100 AM HST Tue Jul 02, 2019

Barbara is a large and powerful hurricane. The latest ASCAT scatterometer data confirms that tropical-storm-force winds extend up to 160 n mi from the center, while the hurricane-force winds extend up to 30 n mi from the center. A very impressive outflow channel exists over nearly a 20 degree swath of ocean to the north of the cyclone. There are at least two mesocyclones evident in the well-defined eye, and cloud tops are colder than -70 degrees C in most of the eyewall. A compromise between the subjective satellite intensity estimates from TAFB and SAB and the objective estimates of CIMSS ADT and SATCON yield an initial intensity of 120 kt for this advisory.

Barbara continues to move toward the west-northwest or 290 degrees at 12 kt, to the south of a mid-level ridge extending from the west coast of the United States westward across the eastern Pacific. Barbara will turn northwestward in 36 to 48 hours as it reaches the southwestern periphery of the ridge. Thereafter, once the cyclone weakens to a shallow system, it should turn back westward steered by the low-level flow as per the majority of the track guidance.

There is still a small window of opportunity today and this evening for additional strengthening of Barbara, while it remains over SSTs greater than 28 deg C and in a low shear environment. The SSTs ahead of Barbara start to decline Wednesday morning due to the forecast track taking the hurricane over progressively cooler waters of about 26.5 deg C in 24 hours, and near 25 deg C in 72 hours. In addition, the cyclone will be approaching a more stable airmass and moving into increasing southwesterly vertical shear within a few days. All of these conditions suggest that Barbara should begin a slow weakening trend on Wednesday, with the weakening accelerating after 48 hours. By the time Barbara reaches the Central Pacific, it is likely to be a tropical storm or even a remnant low.

NOTE: Beginning this hurricane season, all National Hurricane Center eastern Pacific advisory products that utilize local time, and the corresponding graphical products will use Hawaiian Standard Time (HST) instead of Pacific Daylight Time (PDT) or Standard Time (PST) if the final forecast point is west of 140W. Since Barbara’s day 5 official forecast point is now west of 140W, advisory products are now being issued in Hawaiian Standard Time.

FORECAST POSITIONS AND MAX WINDS

INIT  02/2100Z 12.9N 123.2W  120 KT 140 MPH - Category 4 (WSW Hilo, Hawaii)
 12H  03/0600Z 13.4N 124.9W  130 KT 150 MPH - Category 4 (WSW Hilo, Hawaii)
 24H  03/1800Z 14.2N 126.7W  120 KT 140 MPH - Category 4 (WSW Hilo, Hawaii)
 36H  04/0600Z 15.2N 128.5W  110 KT 125 MPH - Category 4 (WSW Hilo, Hawaii)
 48H  04/1800Z 16.4N 130.3W   95 KT 110 MPH - Category 2 (WSW Hilo, Hawaii)
 72H  05/1800Z 18.6N 134.0W   65 KT  75 MPH - Category 1 (WSW Hilo, Hawaii)
 96H  06/1800Z 19.3N 139.0W   45 KT  50 MPH - Tropical Storm  (WSW Hilo, Hawaii)
120H  07/1800Z 19.0N 145.0W   30 KT  35 MPH - Tropical Storm  (WSW Hilo, Hawaii)

NWS National Hurricane Center Miami FL 500 AM HST Tue Jul 02, 2019

Conventional satellite imagery and microwave data revealed that the structure of Barbara has improved significantly. The hurricane has developed an eye surrounded by a ring of very deep convection and both features have been present during the past several hours. This improvement in structure has been accompanied by a substantial intensification and based on both objective and subjective numbers of 6.0 on the Dvorak scale, the initial intensity has been adjusted upward to 115 kt. This is a marked increase of 55 kt since yesterday at this time.

A prevailing warm ocean and low shear could fuel additional intensification during the next 12 hours or so. However, the hurricane is forecast to encounter cooler waters and strong shear primarily beyond 3 days resulting in weakening which could be much faster by the end of the forecast period. By the time Barbara reaches the Central Pacific, it is likely to be a tropical storm or even a remnant low.

Barbara has been moving steadily toward the west and west-northwest or 290 degrees ar 12 kt. The hurricane is moving south of a deep-layer ridge of high pressure extending from the west coast of the United States westward across the Pacific. Barbara should move a little more to the northwest around the ridge in about 2 or 3 days, but as soon as the cyclone weakens and becomes shallow, it will likely move to the west steered by the low-level flow. The NHC track forecast is similar to the previous one, and it is basically on top of the multi-model consensus.

NOTE: Beginning this hurricane season, all National Hurricane Center eastern Pacific advisory products that utilize local time, and the corresponding graphical products will use Hawaiian Standard Time (HST) instead of Pacific Daylight Time (PDT) or Standard Time (PST) if the final forecast point is west of 140W. Since Barbara’s day 5 official forecast point is now west of 140W, advisory products are now being issued in Hawaiian Standard Time.

FORECAST POSITIONS AND MAX WINDS

INIT  02/1500Z 12.5N 122.2W  115 KT 130 MPH - Category 4 (WSW Hilo, Hawaii)
 12H  03/0000Z 12.9N 123.9W  130 KT 150 MPH - Category 4 (WSW Hilo, Hawaii)
 24H  03/1200Z 13.7N 125.9W  125 KT 145 MPH - Category 4 (WSW Hilo, Hawaii)
 36H  04/0000Z 14.6N 127.8W  115 KT 130 MPH - Category 4 (WSW Hilo, Hawaii)
 48H  04/1200Z 15.5N 129.5W  100 KT 115 MPH - Category 3 (WSW Hilo, Hawaii)
 72H  05/1200Z 17.8N 133.0W   75 KT  85 MPH - Category 1 (WSW Hilo, Hawaii)
 96H  06/1200Z 19.0N 137.5W   50 KT  60 MPH - Tropical Storm (WSW Hilo, Hawaii)
120H  07/1200Z 19.0N 143.5W   35 KT  40 MPH - Tropical Storm (WSW Hilo, Hawaii)

Hurricane Barbara Tropical Cyclone Update NWS National Hurricane Center Miami FL 230 AM HST Tue Jul 02, 2019

…BARBARA STRENGTHENING RAPIDLY…

Satellite images show that Barbara has continued to strengthen faster than previously indicated and the maximum winds have reached 130 mph (215 km/h) with higher gusts.

This increase in intensity will be reflected in the next advisory package.

SUMMARY: OF 230 AM HST…1230 UTC…

INFORMATION:

LOCATION: 12.3N 121.6W

ABOUT: 1060 MI…1705 KM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA

MAXIMUM SUSTAINED WINDS: 130 MPH…215 KM/H

PRESENT MOVEMENT: WNW OR 280 DEGREES AT 15 MPH…24 KM/H

MINIMUM CENTRAL PRESSURE:  948 MB…27.99 INCHES

NWS National Hurricane Center Miami FL 1100 PM HST Mon Jul 01 2019

Recent METOP-A and -B microwave images indicate that Barbara’s eyewall is no longer broken and has been able to shield itself from the dry air that had been penetrating the inner core. An eye is also becoming more apparent in infrared satellite imagery. Subjective Dvorak estimate has increased to T5.0/90 kt from TAFB and T5.5/102 kt from SAB, while objective numbers are T5.5/102 kt and 81 kt from UW-CIMSS ADT and SATCON, respectively. Barbara’s initial intensity is therefore set at 95 kt, meaning that the rapid intensification phase continues.

Low vertical shear, beneficial upper-level outflow, and deep warm water are likely to foster additional strengthening for the next 24-36 hours, with Barbara, expected to become a major hurricane soon. Oceanic heat content values decrease markedly by 36 hours, which should lead to gradual weakening, followed by faster weakening on days 4 and 5 when southwesterly shear increases. The updated NHC intensity forecast is not too dissimilar from the previous forecast during the first day or two and still shows Barbara’s peak intensity reaching category 4 intensity during that period. The models are in good agreement that environmental conditions will become quite hostile after day 3, and the new forecast shows a faster weakening rate toward the end of the forecast period. In fact, if the GFS and European models are correct, Barbara could lose its deep convection and become a post-tropical cyclone over the weekend.

Barbara’s trajectory remains westward at 280/13 kt, with steering dominated by a subtropical ridge which extends westward from northern Mexico. The hurricane is expected to gradually reach the western periphery of the ridge in the coming days, which should cause it to turn northwestward and slow down by 48-72 hours. After that time, a weaker Barbara should turn back toward the west and accelerate, steered by lower-level trade winds. Negligible adjustments, primarily after 48 hours, were made to the NHC official track forecast, which lies close to the TVDG multi-model consensus. NOTE: Beginning this hurricane season, all National Hurricane Center eastern Pacific advisory products that utilize local time, and the corresponding graphical products will use Hawaiian Standard Time (HST) instead of Pacific Daylight Time (PDT) or Standard Time (PST) if the final forecast point is west of 140W. Since Barbara’s day 5 official forecast point is now west of 140W, advisory products are now being issued in Hawaiian Standard Time.

FORECAST POSITIONS AND MAX WINDS

INIT  02/0900Z 12.0N 121.1W   95 KT 110 MPH - Category 2 (WSW Hilo. Hawaii)
 12H  02/1800Z 12.4N 122.9W  105 KT 120 MPH - Category 2 (WSW Hilo. Hawaii)
 24H  03/0600Z 13.0N 125.0W  115 KT 130 MPH - Category 4 (WSW Hilo. Hawaii)
 36H  03/1800Z 13.8N 126.9W  120 KT 140 MPH - Category 4 (WSW Hilo. Hawaii)
 48H  04/0600Z 14.7N 128.6W  110 KT 125 MPH - Category 3 (WSW Hilo. Hawaii)
 72H  05/0600Z 16.9N 132.0W   80 KT  90 MPH - Category 1 (WSW Hilo. Hawaii)
 96H  06/0600Z 18.5N 136.0W   55 KT  65 MPH - Tropical Storm (WSW Hilo. Hawaii)
120H  07/0600Z 19.0N 141.5W   40 KT  45 MPH - Tropical Storm (WSW Hilo. Hawaii)

NWS National Hurricane Center Miami FL 800 AM PDT Mon Jul 01, 2019

The satellite presentation of Barbara has continued to improve with the development of a central dense overcast, plenty of convective bands, and an excellent upper-level outflow pattern. The cyclone structure in microwave images has also improved, although the low- and middle-levels are not quite aligned yet. Dvorak T-numbers have continued to gradually increase, and an average of these estimates yields an initial intensity of 60 kt.

The environment of low shear and high ocean temperature favors the significant strengthening of the cyclone, and in fact, Rapid Intensification Indexes provided in the SHIPS model suites are quite high, indicating that more than a 70 percent chance of this process is expected to occur. On this basis, the NHC forecast calls for Barbara to increase in intensity to Category 3 or even 4 on the Saffir/Simpson Hurricane Scale within the next day or two. Beyond 3 days, Barbara will encounter cooler waters and gradual weakening should then begin.Hurricame Barbara Wind Speed July 1 2019

Barbara has decreased its forward speed a little, and the best estimate of the initial motion is toward the west-northwest or 275 degrees at 14 kt. The deep-layer mean flow steering the cyclone is expected to weaken further, and this should result in an additional decrease in the hurricane’s forward speed, but no change in direction. There has been no significant change in the track guidance, and most of the models are still tightly clustered, bringing the hurricane toward the west-northwest through the next 5 days. The NHC track forecast is very similar to the previous one, perhaps a very small shift to the north, but in general, it is basically on top of the multi-model consensus TVCE.

FORECAST POSITIONS AND MAX WINDS

INIT  01/1500Z 11.4N 117.3W   60 KT  70 MPH - Tropical Storm (WSW Acapulco, Mx)
 12H  02/0000Z 11.7N 119.3W   75 KT  85 MPH - Category 1 (WSW Acapulco, Mx)
 24H  02/1200Z 12.2N 121.7W   85 KT 100 MPH - Category 2 (ESE Hilo, Hawaii)
 36H  03/0000Z 12.8N 123.9W  100 KT 115 MPH - Category 3 (ESE Hilo, Hawaii)
 48H  03/1200Z 13.5N 125.8W  115 KT 130 MPH - Category 4 (ESE Hilo, Hawaii)
 72H  04/1200Z 15.1N 129.4W  105 KT 120 MPH - Category 3 (ESE Hilo, Hawaii)
 96H  05/1200Z 17.0N 133.0W   80 KT  90 MPH - Category 1 (ESE Hilo, Hawaii)
120H  06/1200Z 18.0N 137.5W   55 KT  65 MPH - Tropical Storm (ESE Hilo, Hawaii)

NWS National Hurricane Center Miami FL 500 AM PDT Mon Jul 1, 2019

For the eastern North Pacific…east of 140 degrees west longitude: The National Hurricane Center is issuing advisories on Tropical Storm Barbara, located several hundred miles south-southwest of the southern tip of the Baja California peninsula.

NWS National Hurricane Center Miami FL 200 AM PDT Mon Jul 01, 2019

Although earlier microwave imagery indicated that Barbara was still being affected by moderate northwesterly shear, the upper-level the outflow has expanded overnight and the center appears to be more embedded within the area of very cold cloud tops. A couple of earlier ASCAT passes revealed peak winds of 50 kt, and a much larger area of tropical-storm-force winds over the eastern semicircle of the cyclone than previously analyzed. Due to the typical undersampling of peak winds in the ASCAT instrument, the initial intensity has been increased to 55 kt, which is also in good agreement with the latest TAFB Dvorak intensity estimate, and ADT and SATCON estimate from UW/CIMSS.

As mentioned in the previous advisory, the global models continue to forecast a reduction in the deep-layer vertical wind shear during the next couple of days while Barbara moves over warm sea surface temperatures. These conditions are expected to allow steady to perhaps rapid strengthening over the next couple of days. The SHIPS, FSSE, and HCCA models are quite aggressive and predict rapid strengthening during the next 24 to 36 h, while the HWRF and HMON models are somewhat lower. Given the current structure of the cyclone, the NHC forecast is a little below the more aggressive models, but still predicts significant strengthening during the next 24 to 48 hours. After 72 hours, cooler waters and increasing southwesterly shear are expected to cause gradual weakening.

The initial motion estimate is 275/18 kt. A deep-layer ridge to the north of the storm is forecast to gradually weaken over the next several days. This should cause Barbara to slow down and turn west-northwestward within the next day or so. By 96 h, the ridge is forecast to build westward which should cause the cyclone to turn back toward the west. While the dynamical models generally agree on the overall scenario there are some differences in the predicted forward speed and how far north Barbara will move. The NHC forecast splits these differences and lies near the middle of the guidance envelope, closest to the Florida State Superensemble.

FORECAST POSITIONS AND MAX WINDS

INIT  01/0900Z 11.2N 115.8W   55 KT  65 MPH - Tropical Storm (WSW Acapulco, Mx)
 12H  01/1800Z 11.5N 117.9W   65 KT  75 MPH - Category 1 (WSW Acapulco, Mx)
 24H  02/0600Z 11.9N 120.5W   80 KT  90 MPH - Category 1 (WSW Acapulco, Mx)
 36H  02/1800Z 12.4N 122.7W   95 KT 110 MPH - Category 2 (WSW Acapulco, Mx)
 48H  03/0600Z 13.0N 124.7W  105 KT 120 MPH - Category 3 (ESE Hilo, Hawaii)
 72H  04/0600Z 14.5N 128.3W  105 KT 120 MPH - Category 3 (ESE Hilo, Hawaii)
 96H  05/0600Z 16.3N 132.0W   85 KT 100 MPH - Category 2 (ESE Hilo, Hawaii)
120H  06/0600Z 17.2N 136.2W   70 KT  80 MPH - Category 1 (ESE Hilo, Hawaii)

NWS National Hurricane Center Miami FL EP022019 900 PM MDT Sun Jun 30, 2019

Barbara has continued to strengthen despite modest northwesterly mid-level vertical wind shear that has been undercutting a rapidly improving upper-level outflow pattern. Passive microwave satellite images over the past few hours indicate that the low-level center is displaced to the west of the coldest overshooting tops due to the aforementioned shear conditions. The initial intensity has been increased to 45 kt based on a consensus Dvorak intensity of T3.0/45 from TAFB and SAB, which is consistent with a late-arriving 1647Z ASCAT-C overpass that contained wind vectors of 41-42 kt.

The initial motion is an unusually brisk 275/19 kt. A deep-layer ridge to the north of Barbara is expected to steer the tropical cyclone westward to west-northwestward for the next 48-72 hours, accompanied by a gradual decrease in forward speed. By 96 hours, a shortwave trough is forecast to weaken the ridge, allowing Barbara to turn more toward the northwest and gain some latitude. By day 5, however, the ridge is forecast to build back in behind the exiting trough, which should force the cyclone back on a west-northwesterly to westerly track. The latest track guidance continues to be tightly clustered with the HWRF remaining on the north side of the envelope and the ECMWF on the south side. The new NHC track forecast is similar to but a little south of the previous advisory track, and lies close to a blend of the TVCE, HCCA, and FSSE consensus models.

The global models continue to forecast the deep-layer and mid-level vertical wind shear to steadily decrease from the current 15 kt to near 5 kt by 48-72 hours. The low shear conditions, along with SSTs of 28-29 deg C, should allow for at least steady strengthening for the next 48 h or so, followed by more significant strengthening in the 48-72 h time period. After that time, cooler water temperatures beneath the cyclone coupled with the strong inner-core wind field are expected to result in significant cold upwelling, which should induce steady weakening on days 4-5. Rapid intensification in the 24-72 h time frame is a distinct possibility, which would result in Barbara becoming a stronger major hurricane than currently forecast. The new official intensity forecast is a little more robust than the previous advisory, and follows a blend of the HCCA, ICON, and FSSE intensity consensus models.

FORECAST POSITIONS AND MAX WINDS

INIT  01/0300Z 11.0N 114.2W   45 KT  50 MPH - Tropical Storm (WSW Acapulco, Mx)
 12H  01/1200Z 11.5N 116.3W   55 KT  65 MPH - Tropical Storm (WSW Acapulco, Mx)
 24H  02/0000Z 11.9N 119.0W   65 KT  75 MPH - Category 1 (WSW Acapulco, Mx)
 36H  02/1200Z 12.3N 121.4W   75 KT  85 MPH - Category 1 (WSW Acapulco, Mx)
 48H  03/0000Z 12.8N 123.5W   90 KT 105 MPH - Category 2 (ESE Hilo. Hawaii)
 72H  04/0000Z 14.0N 127.0W  105 KT 120 MPH - Category 3 (ESE Hilo. Hawaii)
 96H  05/0000Z 15.7N 130.7W   90 KT 105 MPH - Category 2 (ESE Hilo. Hawaii)
120H  06/0000Z 16.8N 135.0W   75 KT  85 MPH - Category 1 (ESE Hilo. Hawaii)

NWS National Hurricane Center Miami FL 500 AM PDT Sun Jun 30, 2019

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

1. Satellite imagery is indicating that the area of low pressure located several hundred miles southwest of the southern coast of Mexico continues to become better organized, and a tropical storm may be developing. If this trend continues, advisories may be initiated later this morning on this system as it moves westward to west-northwestward at about 15 mph. For additional information on this low see High Seas Forecasts issued by the National Weather Service.

* Formation chance through 48 hours…high…near 100 percent. * Formation chance through 5 days…high…near 100 percent.

NWS National Hurricane Center Miami FL 1100 PM PDT Sat Jun 29, 2019

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

Showers and thunderstorms associated with a broad area of low pressure located about 750 miles southwest of the southwestern coast of Mexico continue to gradually become better organized. Environmental conditions are conducive for additional development and a tropical depression or storm is likely to form on Sunday while the disturbance moves westward to west-northwestward at about 15 mph.

* Formation chance through 48 hours…high…near 100 percent. * Formation chance through 5 days…high…near 100 percent.

NWS National Hurricane Center Miami FL 500 PM PDT Sat Jun 29, 2019

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

A broad area of low pressure is located several hundred miles to the southwest of the southern coast of Mexico. The associated showers and thunderstorms continue to gradually become better organized, and a tropical depression is likely to form in the next day or so while the disturbance moves westward to west-northwestward at about 15 mph.

* Formation chance through 48 hours…high…90 percent. * Formation chance through 5 days…high...90 percent.

NWS National Hurricane Center Miami FL 1100 AM PDT Sat Jun 29, 2019

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

The National Hurricane Center has issued the last advisory on post-tropical cyclone Alvin located several hundred miles west of the southern tip of the Baja California peninsula. 1. A broad area of low pressure has developed well to the southwest of the southern coast of Mexico. The associated showers and thunderstorms are gradually becoming better organized, and a tropical depression is likely to form in the next day or two while the disturbance moves westward to west-northwestward at about 15 mph.

* Formation chance through 48 hours…high…90 percent. * Formation chance through 5 days…high…90 percent.

NWS National Hurricane Center Miami FL 500 AM PDT Sat Jun 29, 2019

Corrected to make Alvin a depression For the eastern North Pacific…east of 140 degrees west longitude: The National Hurricane Center is issuing advisories on recently downgraded Tropical Depression Alvin, located several hundred miles west of the southern tip of the Baja California peninsula.

1. A broad area of showers and thunderstorms located well to the southwest of the southern coast of Mexico is associated with a tropical wave. Environmental conditions are expected to be conducive for development of this system, and a tropical depression is likely to form late this weekend or early next week while the disturbance moves westward to west-northwestward at about 15 mph.

* Formation chance through 48 hours…high…80 percent. * Formation chance through 5 days…high...90 percent.

NWS National Hurricane Center Miami FL 500 PM PDT Fri Jun 28, 2019

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

The National Hurricane Center is issuing advisories on Tropical Storm Alvin, located several hundred miles west-southwest of the southern tip of the Baja California peninsula.

1. An elongated area of showers and thunderstorms located well to the southwest of the southern coast of Mexico is associated with a tropical wave. Environmental conditions are expected to be conducive for development of this system, and a tropical depression is likely to form late this weekend or early next week while the disturbance moves westward to west-northwestward at about 15 mph.

* Formation chance through 48 hours…medium…60 percent. * Formation chance through 5 days…high…90 percent.

NWS National Hurricane Center Miami FL 1100 AM PDT Fri Jun 28, 2019

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

The National Hurricane Center is issuing advisories on Tropical Storm Alvin, located several hundred miles west-southwest of the southern tip of the Baja California peninsula.

1. Disorganized showers and thunderstorms located several hundred miles south of Acapulco, Mexico are associated with a tropical wave. Environmental conditions are expected to be conducive for the development of this system over the next several days, and a tropical depression is likely to form late this weekend or early next week while the disturbance moves westward to west-northwestward well away from the coast of Mexico.

* Formation chance through 48 hours…medium…40 percent. * Formation chance through 5 days…high…80 percent.

NWS National Hurricane Center Miami FL 500 AM PDT Fri Jun 28, 2019

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

The National Hurricane Center is issuing advisories on recently downgraded Tropical Storm Alvin, located several hundred miles southwest of the southern tip of the Baja California peninsula.

A tropical wave located several hundred miles south-southwest of the Gulf of Tehuantepec is producing disorganized showers and thunderstorms. Environmental conditions are expected to be conducive for the development of this system over the next several days, and a tropical depression is likely to form late this weekend or early next week while the disturbance moves westward to west-northwestward well away from the coast of Mexico.

* Formation chance through 48 hours…medium…40 percent. * Formation chance through 5 days…high…80 percent

NWS National Hurricane Center Miami FL 1100 PM PDT Thu Jun 27, 2019

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

The National Hurricane Center is issuing advisories on Hurricane Alvin, located several hundred miles southwest of the southern tip of the Baja California peninsula.

1. A tropical wave located several hundred miles south of the Gulf of Tehuantepec is producing disorganized showers and a few thunderstorms. Environmental conditions are expected to be conducive for the development of this system over the next several days, and a tropical depression is likely to form late this weekend or early next week while the disturbance moves westward to west-northwestward well away from the coast of Mexico.

* Formation chance through 48 hours…low…30 percent. * Formation chance through 5 days…high…70 percent.

NWS National Hurricane Center Miami FL 500 PM PDT Thu Jun 27, 2019

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

The National Hurricane Center is issuing advisories on Tropical Storm Alvin, located several hundred miles south-southwest of the southern tip of the Baja California peninsula.

1. A tropical wave is producing disorganized showers and a few thunderstorms several hundred miles south of the Gulf of Tehuantepec. An area of low pressure is expected to develop from this wave over the next couple of days, and a tropical depression could form by late this weekend or early next week while the system moves westward to west-northwestward well away from the coast of Mexico.

* Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…medium…60 percent.

NWS National Hurricane Center Miami FL 1100 AM PDT Thu Jun 27, 2019

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

The National Hurricane Center is issuing advisories on Tropical Storm Alvin, located several hundred miles south-southwest of the southern tip of the Baja California peninsula.

An area of low pressure is expected to develop in a few days several hundred miles southwest of the southern coast of Mexico. Some slow development of this system is possible thereafter and a tropical depression could develop by late this weekend or early next week while it moves westward to west-northwestward.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium…50 percent.

NWS National Hurricane Center Miami FL 500 AM PDT Thu Jun 27, 2019

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

The National Hurricane Center is issuing advisories on Tropical Storm Alvin, located several hundred miles south of the southern tip of the Baja California peninsula.

1. An area of low pressure is expected to develop in a few days several hundred miles southwest of the southern coast of Mexico. Some slow development of this system is possible thereafter and a tropical depression could develop by late this weekend or early next week while it moves westward to west-northwestward.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium…40 percent.

NWS National Hurricane Center Miami FL 1100 PM PDT Wed Jun 26, 2019

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

The National Hurricane Center is issuing advisories on Tropical Storm Alvin, located several hundred miles south of the southern tip of the Baja California peninsula.

1. An area of low pressure is expected to develop in a few days several hundred miles southwest of the southern coast of Mexico. Some slow development of this system is possible over the weekend and into early next week while it moves westward to west-northwestward.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…30 percent.

NWS National Hurricane Center Miami FL 500 PM PDT Wed Jun 26, 2019

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

The National Hurricane Center is issuing advisories on Tropical Storm Alvin, located several hundred miles southwest of Manzanillo, Mexico.

1. An area of low pressure is expected to develop in a few days several hundred miles southwest of the southern coast of Mexico. Some slow development of this system is possible over the weekend and into early next week as it moves westward to west-northwestward.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent

Tropical Weather Outlook NWS National Hurricane Center Miami FL 1100 AM PDT Wed Jun 26, 2019

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

The National Hurricane Center is issuing advisories on recently upgraded Tropical Storm Alvin, located a several hundred miles southwest of Manzanillo, Mexico. 1. An area of low pressure is expected to develop in a few days several hundred miles southwest of the southern coast of Mexico. Some slow development of this system is possible over the weekend and into early next week as it moves westward to west-northwestward.

* Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low...20 percent.

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Video: Hurricane Barbara Update 11p 7-3-19