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Tropical Depression FOURTEEN-E Forecast Discussion Number 1

2015-08-31 22:39:35| National Hurricane Center (East Pacific)

Issued at 300 PM MDT MON AUG 31 2015 000 WTPZ44 KNHC 312039 TCDEP4 TROPICAL DEPRESSION FOURTEEN-E DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL EP142015 300 PM MDT MON AUG 31 2015 Animation of recent visible satellite imagery indicates that the low pressure area well to the south of Cabo San Lucas, Mexico has a well-defined circulation. Recently, deep convection has formed near and partially over the center. On this basis, the system is being designated as a tropical depression. The current intensity estimate is 30 kt, which is slightly above the subjective Dvorak estimates at 1800 UTC. The tropical cyclone is not in an ideal environment for strengthening. A broad upper-level cyclone to the northwest is producing southwesterly shear in the path of the depression, and global models predict that this shear may briefly relax in 1 to 2 days, but increase thereafter. Although the official intensity forecast is on the high side of the guidance, it nonetheless shows weakening to a remnant low by the end of the forecast period. The initial motion estimate is 305/9 kt. A mid-level ridge currently to the north of the depression is forecast to shift eastward over the next few days. As a result, the tropical cyclone should turn toward the north in 48 to 72 hours. There is some spread in the model guidance, including significant differences in predicted forward speed. As a compromise, the official track forecast is roughly in the middle of the guidance, and close to the dynamical model consensus. FORECAST POSITIONS AND MAX WINDS INIT 31/2100Z 12.4N 111.8W 30 KT 35 MPH 12H 01/0600Z 13.5N 113.0W 35 KT 40 MPH 24H 01/1800Z 14.7N 114.2W 40 KT 45 MPH 36H 02/0600Z 16.3N 115.0W 45 KT 50 MPH 48H 02/1800Z 18.3N 115.6W 45 KT 50 MPH 72H 03/1800Z 21.2N 115.7W 35 KT 40 MPH 96H 04/1800Z 23.3N 114.7W 30 KT 35 MPH 120H 05/1800Z 24.6N 114.4W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Cangialosi/Pasch

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Hurricane JIMENA Forecast Discussion Number 21

2015-08-31 22:35:04| National Hurricane Center (East Pacific)

Issued at 200 PM PDT MON AUG 31 2015 000 WTPZ43 KNHC 312034 TCDEP3 HURRICANE JIMENA DISCUSSION NUMBER 21 NWS NATIONAL HURRICANE CENTER MIAMI FL EP132015 200 PM PDT MON AUG 31 2015 Jimena continues to exhibit a concentric eyewall structure around a 20 n mi diameter eye. The cloud tops have warmed a little during the past few hours, and the overall satellite presentation is not quite as impressive as it was several hours ago. The Dvorak Final T-numbers from TAFB and SAB have decreased slightly, and the initial wind speed is lowered a little to 125 kt. The hurricane is still moving westward at about 14 kt, which is a little faster than previously predicted. A mid-level high pressure system located to the north of the tropical cyclone should continue to steer Jimena west-northwestward in the short term, but this ridge is expected to weaken during the next day or two in response to an amplification of a mid- to upper- level trough extending southwestward from the western United States. This pattern change should cause the steering currents around Jimena to weaken, resulting in a gradual northwestward turn with a dramatic decrease in forward speed after 48 hours. The track model guidance has shifted a little to the left and is slightly faster than earlier, and the new NHC track forecast follows that theme. Jimena is likely to fluctuate in intensity during the next 12 to 24 hours while it remains embedded in a very low wind shear environment and over 28 deg C waters. After that time, a slow weakening is expected while SSTs decrease along the forecast track. The NHC intensity forecast is just an update of the previous one and remains on the high side of the intensity guidance, giving some weight to the global models which maintain a very strong cyclone for the next several days. FORECAST POSITIONS AND MAX WINDS INIT 31/2100Z 15.9N 136.8W 125 KT 145 MPH 12H 01/0600Z 16.4N 138.4W 125 KT 145 MPH 24H 01/1800Z 17.1N 140.1W 120 KT 140 MPH 36H 02/0600Z 17.6N 141.2W 110 KT 125 MPH 48H 02/1800Z 18.2N 142.1W 100 KT 115 MPH 72H 03/1800Z 19.2N 143.2W 90 KT 105 MPH 96H 04/1800Z 20.2N 144.0W 80 KT 90 MPH 120H 05/1800Z 21.6N 144.7W 70 KT 80 MPH $$ Forecaster Cangialosi

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Hurricane FRED Forecast Discussion Number 7

2015-08-31 16:51:59| National Hurricane Center (Atlantic)

Issued at 1100 AM AST MON AUG 31 2015 000 WTNT41 KNHC 311451 TCDAT1 HURRICANE FRED DISCUSSION NUMBER 7 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062015 1100 AM AST MON AUG 31 2015 Visible satellite pictures and earlier microwave data indicate that Fred has a well-defined inner core. The outer banding that was noted yesterday is no longer evident, and the hurricane is quite compact. A well-defined eye was evident in both a 0904 UTC SSMIS and 1121 UTC AMSU microwave overpasses. The initial intensity is raised to 75 kt, which is between the latest objective and subjective satellite estimates from UW/CIMSS and TAFB, respectively. Satellite data suggest that the eye of Fred passed just southwest of Boa Vista Island in the Cape Verde Islands, however the northeastern eyewall likely moved over a portion of that island just before 1200 UTC this morning. The sea surface temperatures along the path of Fred are beginning to decrease, however, the vertical shear is expected to remain quite low for another 12 hours or so. Little change in strength is expected today. By Tuesday, Fred will be over SSTS of around 26C and southwesterly shear is forecast to increase. This should cause gradual weakening, and a further increase in shear and a drier, more stable air mass should cause a faster rate of decay after 36 hours. The tropical cyclone is now forecast to become a tropical depression in about 4 days, and degenerate to a remnant low by the end of the forecast period. Fred continues to move northwestward at about 10 kt. The hurricane should maintain a northwestward heading during the next 12 to 24 hours. During this time, the center of Fred is expected to pass over or very close to the northwestern Cape Verde Islands of Sao Nicolou, Santa Luzuia, Sao Vicente, and Sao Antao. On Tuesday, a west- northwestward turn is predicted as a mid-level ridge builds to the north of the cyclone. Fred should then maintain a west-northwestward heading during the remainder of the forecast period. The NHC track remains on the south side of the guidance envelope, in best agreement with a consensus of the typically reliable GFS and ECMWF models. According to the official Atlantic tropical cyclone record, which begins in 1851, Fred is the first hurricane to pass through the Cape Verde Islands since 1892. We caution, however, that the database is less reliable prior to the satellite era (mid 1960s onward). Please note that the track/cone graphic, an automatically generated product, does not have the capability of displaying warnings for the Cape Verde Islands. FORECAST POSITIONS AND MAX WINDS INIT 31/1500Z 16.4N 23.7W 75 KT 85 MPH 12H 01/0000Z 17.3N 25.1W 70 KT 80 MPH 24H 01/1200Z 18.6N 26.9W 65 KT 75 MPH 36H 02/0000Z 19.6N 28.8W 60 KT 70 MPH 48H 02/1200Z 20.3N 30.6W 50 KT 60 MPH 72H 03/1200Z 21.4N 33.8W 40 KT 45 MPH 96H 04/1200Z 22.5N 37.5W 30 KT 35 MPH 120H 05/1200Z 24.0N 41.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Brown

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Hurricane JIMENA Forecast Discussion Number 20

2015-08-31 16:45:29| National Hurricane Center (East Pacific)

Issued at 800 AM PDT MON AUG 31 2015 000 WTPZ43 KNHC 311445 TCDEP3 HURRICANE JIMENA DISCUSSION NUMBER 20 NWS NATIONAL HURRICANE CENTER MIAMI FL EP132015 800 AM PDT MON AUG 31 2015 Jimena continues to be a powerful hurricane. Recent microwave data and infrared satellite images suggest that the system still has concentric eyewalls. The eye of the hurricane remains distinct and has a diameter of about 20 n mi, and the convective pattern is slightly asymmetric with cloud tops slightly warmer west of the eye. Satellite intensity estimates were all 6.5 on the Dvorak scale, therefore, the initial wind speed remains 130 kt. The hurricane is now moving westward at about 14 kt steered by a mid-level high pressure system to the north of the cyclone. This ridge is expected to break down during the next couple of days while a trough deepens near the west coast of the United States. This pattern evolution should weaken the steering currents for Jimena, causing a gradual slow down and a turn to the northwest during the next several days. The track model guidance is in good agreement on this scenario, and only minor tweaks were made to the previous track forecast. The new NHC track prediction lies close to the various consensus aids. Jimena is expected to more or less maintain its intensity during the next day or so while it remains over 28 deg C water and in a very low wind shear environment. Fluctuations in strength are possible during that time due to the ongoing eyewall cycles. After that time, a slow weakening is expected while water temperatures lower along the forecast track. The NHC intensity forecast lies on the high side of the guidance and is a little above the previous intensity forecast, giving some weight to the global models which maintain a very strong cyclone for the next several days. FORECAST POSITIONS AND MAX WINDS INIT 31/1500Z 15.6N 135.3W 130 KT 150 MPH 12H 01/0000Z 16.0N 137.1W 125 KT 145 MPH 24H 01/1200Z 16.6N 138.9W 125 KT 145 MPH 36H 02/0000Z 17.3N 140.3W 115 KT 130 MPH 48H 02/1200Z 17.8N 141.2W 105 KT 120 MPH 72H 03/1200Z 18.9N 142.5W 95 KT 110 MPH 96H 04/1200Z 19.9N 143.2W 85 KT 100 MPH 120H 05/1200Z 20.9N 143.8W 75 KT 85 MPH $$ Forecaster Cangialosi

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Hurricane JIMENA Forecast Discussion Number 19

2015-08-31 10:56:59| National Hurricane Center (East Pacific)

Issued at 200 AM PDT MON AUG 31 2015 000 WTPZ43 KNHC 310856 TCDEP3 HURRICANE JIMENA DISCUSSION NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL EP132015 200 AM PDT MON AUG 31 2015 Jimena has maintained a symmetric very cold CDO with a well-defined 25 n mi diameter eye. A 0307Z SSMIS pass indicated that a concentric eyewall structure was in place with a secondary eyewall located about 30-40 n mi from the center. A blend of subjective TAFB and SAB Dvorak classifications along with UW-CIMSS Advanced Dvorak Technique are the basis for Jimena's 130-kt intensity. Currently, Jimena is over warm 28 deg C water and is embedded in weak northerly vertical shear conditions. While these should favor continuing an extreme intensity, the mid-level moisture is somewhat dry and the atmosphere not very unstable for deep convection. During the next few days, the SSTs should gradually cool while the vertical shear should gradually increase as Jimena moves west-northwestward. Complicating the forecast is the possibility that Jimena may undergo another concentric eyewall cycle, with short-term weakening followed by possible reintensification. However, such variations are difficult to precisely predict. The intensity forecast is nearly the same as from the previous advisory and is closest to the statistical SHIPS model from 12 to 36 hours, and is close to the IVCN consensus technique thereafter. Jimena is moving quickly toward the west-northwest at 15 kt, primarily through the steering induced by a deep-layer ridge to its north. The ridge should weaken and become oriented northwest-to-southeast during the next couple of days. This should result in Jimena turning toward the northwest at a slower rate of speed. The forecast track is nearly identical to the previous advisory and is based upon the very tightly packed consensus of the skillful dynamical models. Jimena's wind radii were significantly adjusted outward based upon an 0216Z CIRA AMSU pass and an 0536Z partial ASCAT pass. FORECAST POSITIONS AND MAX WINDS INIT 31/0900Z 15.3N 133.9W 130 KT 150 MPH 12H 31/1800Z 15.7N 135.9W 125 KT 145 MPH 24H 01/0600Z 16.3N 137.9W 120 KT 140 MPH 36H 01/1800Z 16.9N 139.4W 110 KT 125 MPH 48H 02/0600Z 17.5N 140.5W 100 KT 115 MPH 72H 03/0600Z 18.5N 142.0W 90 KT 105 MPH 96H 04/0600Z 19.5N 143.0W 80 KT 90 MPH 120H 05/0600Z 20.5N 144.0W 70 KT 80 MPH $$ Forecaster Landsea

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