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Tropical Storm ORLENE Forecast Discussion Number 2

2016-09-11 10:37:02| National Hurricane Center (East Pacific)

Issued at 200 AM PDT SUN SEP 11 2016 000 WTPZ41 KNHC 110836 TCDEP1 TROPICAL STORM ORLENE DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL EP162016 200 AM PDT SUN SEP 11 2016 There has been an impressive increase in the organization of the depression's cloud pattern since the last advisory. An ASCAT pass indicates that the low-level center is located just inside what appears to be a formative central dense overcast (CDO), whose cloud top temperatures have cooled significantly. A well-developed convective band also spirals outward from the CDO, now covering much of the western semicircle of the circulation. The earlier ASCAT pass showed peak uncontaminated winds of 32 kt. Given this datum, a satellite classification of T2.5 from TAFB, and some further increase in organization since the time of the pass, the initial intensity estimate is increased to 35 kt. The best estimate of Orlene's initial motion estimate is 315/11. The cyclone should move west-northwestward to northwestward around the southwestern periphery of a mid-level ridge over northern Mexico today. In 24 to 48 hours, Orlene's forward motion should decrease significantly when the cyclone encounters a weakness in the subtropical ridge between 120W and 125W, caused by a southward extension of a mid- to upper-level trough near the United States West Coast. A further reduction in forward speed and a turn toward the north-northwest is expected by 72 hours, and Orlene could even come to a halt in the face of weak steering around this time. There is widespread agreement in the guidance that the subtropical ridge will re-establish itself north of Orlene in about 4 days, which should result in a westward or possibly a west-southwestward motion with an increase in forward speed. Overall, little change was made to the previous forecast track, and the current one is close to a consensus based on the ECMWF and GFS solutions. East-northeasterly shear currently over Orlene is forecast to diminish during the next couple of days while the cyclone moves over warm waters. Steady strengthening is expected, even though the mid-level moisture will be only marginally favorable and SSTs will begin to gradually lower. If Orlene can quickly establish an inner core, the result could be greater intensification than this forecast predicts. The intensity forecast becomes challenging after 48 hours since Orlene should be straddling the 26.5-deg C isotherm for the remainder of the forecast period while the environmental moisture becomes critically low. There could also be some temporary increase in southwesterly shear. The combination of these factors should result in a steady-state or slowly weakening cyclone from 72-120 hours. The NHC intensity forecast is a little above the previous one, near the multi-model consensus, but lower than the SHIPS and FSU Superensemble output. FORECAST POSITIONS AND MAX WINDS INIT 11/0900Z 14.8N 115.9W 35 KT 40 MPH 12H 11/1800Z 15.8N 117.4W 45 KT 50 MPH 24H 12/0600Z 16.8N 119.0W 55 KT 65 MPH 36H 12/1800Z 17.6N 120.0W 65 KT 75 MPH 48H 13/0600Z 18.2N 120.5W 75 KT 85 MPH 72H 14/0600Z 19.1N 120.9W 75 KT 85 MPH 96H 15/0600Z 19.1N 123.1W 70 KT 80 MPH 120H 16/0600Z 18.8N 127.2W 65 KT 75 MPH $$ Forecaster Kimberlain

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Tropical Depression SIXTEEN-E Forecast Discussion Number 1

2016-09-11 04:34:28| National Hurricane Center (East Pacific)

Issued at 900 PM MDT SAT SEP 10 2016 000 WTPZ41 KNHC 110234 TCDEP1 TROPICAL DEPRESSION SIXTEEN-E DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL EP162016 900 PM MDT SAT SEP 10 2016 The area of low pressure southwest of Mexico has become better organized during the last several hours. Earlier ASCAT data indicated that the low had a well-defined center, and the latest infrared images show enough organized deep convection in a band in the northwestern quadrant declare this system a tropical depression. The initial wind speed is set to 30 kt in accordance with the TAFB satellite estimate. This is the earliest 16th tropical cyclone formation in the eastern Pacific since 1992. The depression is forecast to be in an environment of light shear, warm waters and a humid mid-level atmosphere for at least a few days. There are no obvious reasons why this cyclone would not intensify, other than a somewhat broad initial wind structure, and guidance is in fairly good agreement on at least gradual strengthening for the next few days. The NHC intensity forecast is near or slightly above the intensity guidance after 24 hours, and this forecast could turn out to be conservative, especially in a few days, if the system develops an inner core. The long range intensity is leveled off due to the uncertainty of what latitude the cyclone will be located at after day 3, which is pretty critical in that portion of the eastern Pacific due to the tight SST gradient. An uncertain estimate of initial motion is 310/10. The depression is likely to move generally northwestward for the next couple of days around a mid-level ridge centered over Mexico. A weakness in the ridge near 120-125 degrees west should cause the cyclone to turn north-northwestward and decelerate as it enters weaker steering currents near the ridge axis. The weakness is forecast to fill in by all the models on days 4 and 5, and this restrengthened ridge would steer the cyclone generally westward at a faster forward speed near the end of the forecast period. Overall, the models agree on the synoptic scenario, albeit with some timing disagreements. The NHC forecast track is close to the model consensus, which has been an excellent guidance tool to smooth through the along and cross track model differences so far in the 2016 eastern Pacific season. FORECAST POSITIONS AND MAX WINDS INIT 11/0300Z 13.9N 114.9W 30 KT 35 MPH 12H 11/1200Z 14.9N 116.3W 35 KT 40 MPH 24H 12/0000Z 16.0N 118.2W 45 KT 50 MPH 36H 12/1200Z 16.9N 119.6W 55 KT 65 MPH 48H 13/0000Z 17.7N 120.3W 65 KT 75 MPH 72H 14/0000Z 18.9N 120.7W 70 KT 80 MPH 96H 15/0000Z 19.1N 122.5W 65 KT 75 MPH 120H 16/0000Z 19.0N 126.0W 65 KT 75 MPH $$ Forecaster Blake

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Tropical Storm NEWTON Forecast Discussion Number 12

2016-09-07 16:37:35| National Hurricane Center (East Pacific)

Issued at 900 AM MDT WED SEP 07 2016 000 WTPZ45 KNHC 071437 TCDEP5 TROPICAL STORM NEWTON DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL EP152016 900 AM MDT WED SEP 07 2016 Even after landfall, Newton has been producing a noteworthy burst of deep convection that will be moving into southeastern Arizona very soon. However, the low-level center is becoming partially exposed to the south and southwest of the convection due to almost 30 kt of shear. The maximum winds are reduced to 45 kt based on a steady decay rate, but without observations this estimate is quite uncertain. For what it's worth, the NWS WSR-88D from Tucson, Arizona, is showing 50-kt winds at an elevation of 10,000 ft, so an intensity between 40-45 kt seems reasonable. Newton has turned north-northeastward with an initial motion of 015/16 kt. This motion is expected to continue for the next 12-24 hours before Newton dissipates. After that time, Newton's remnants could turn eastward and move into southern New Mexico and western Texas. Based on the decay rate shown by the intensity models, Newton could still move into Arizona as a tropical storm this afternoon, but it is expected to weaken to a tropical depression by this evening. Regardless of Newton's exact intensity, it is important to remember that wind speeds on the tops of hills and mountains could be higher than the surface wind speeds indicated in the forecast. The rugged terrain should cause the cyclone to dissipate overnight. The main concern with this system will be heavy rainfall that will continue spreading from northwestern Mexico into Arizona and New Mexico over the next day or so. These rains could cause flooding and mud slides. Consult statements from you local weather offices for possible flash flood warnings. FORECAST POSITIONS AND MAX WINDS INIT 07/1500Z 30.2N 111.3W 45 KT 50 MPH...INLAND 12H 08/0000Z 32.4N 110.0W 30 KT 35 MPH...INLAND 24H 08/1200Z...DISSIPATED $$ Forecaster Berg

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Tropical Storm NEWTON Forecast Discussion Number 11

2016-09-07 10:53:19| National Hurricane Center (East Pacific)

Issued at 300 AM MDT WED SEP 07 2016 000 WTPZ45 KNHC 070852 TCDEP5 TROPICAL STORM NEWTON DISCUSSION NUMBER 11 NWS NATIONAL HURRICANE CENTER MIAMI FL EP152016 300 AM MDT WED SEP 07 2016 Satellite images and surface observations indicate that the center has made landfall in mainland Mexico a short distance southeast of Bahia Kino. The overall cloud pattern has deteriorated somewhat, with an erosion of deep convection over the northwestern quadrant of the circulation, and subjective and objective Dvorak intensity estimates are below hurricane strength. Therefore the system has been downgraded to a 60-kt tropical storm. With the center moving inland, rapid weakening will occur, however there is a possibility that Newton could bring tropical-storm-force winds to portions of extreme southeastern Arizona later today. The circulation is expected to dissipate on Thursday. The initial motion is northward, or 010/15 kt. The latest NHC track forecast is very similar to the previous one. Newton should gradually curve to the northeast as it moves between the western periphery of a mid-level high and a broad trough to the north. The official forecast follows the multi-model consensus. The main concern with this system will be heavy rainfall that will be spreading from northwestern Mexico into Arizona and New Mexico over the next day or so. These rains could cause flooding and mud slides. Consult statements from you local weather offices for possible warnings. FORECAST POSITIONS AND MAX WINDS INIT 07/0900Z 28.7N 111.8W 60 KT 70 MPH 12H 07/1800Z 31.4N 111.0W 35 KT 40 MPH...INLAND 24H 08/0600Z 33.5N 108.8W 25 KT 30 MPH...POST-TROP/REMNT LOW 36H 08/1800Z...DISSIPATED $$ Forecaster Pasch

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Hurricane NEWTON Forecast Discussion Number 10

2016-09-07 04:32:59| National Hurricane Center (East Pacific)

Issued at 900 PM MDT TUE SEP 06 2016 000 WTPZ45 KNHC 070232 TCDEP5 HURRICANE NEWTON DISCUSSION NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL EP152016 900 PM MDT TUE SEP 06 2016 The cloud pattern of Newton has not changed much since the previous advisory, so the initial intensity remains a possibly generous 65 kt, with the strongest winds likely found east of the center over the Gulf of California. Little change in intensity is forecast before Newton moves inland over northwestern Mexico early Wednesday. Rapid weakening is expected after that time, but Newton could still reach southeastern Arizona as a tropical storm on Wednesday. Newton's surface circulation is forecast to dissipate by 36 hours. The initial motion estimate is 350/15. Newton is positioned between a mid-level ridge centered over the south-central United States and a mid- to upper-level trough moving into the western United States. Newton should move northward and then north-northeastward under the influence of these steering features through dissipation. The new NHC Track forecast is an update of the previous one and is close to the multi-model consensus. Newton is a large tropical cyclone with hazards extending well away from the center, and these hazards will affect portions of northwestern Mexico and southeastern Arizona during the next day or so. Moisture associated with the remnants of Newton are likely to cause heavy rains and localized flash flooding over parts of Arizona and New Mexico Wednesday and Thursday. FORECAST POSITIONS AND MAX WINDS INIT 07/0300Z 27.3N 112.0W 65 KT 75 MPH 12H 07/1200Z 29.8N 111.8W 50 KT 60 MPH...INLAND 24H 08/0000Z 32.7N 110.5W 30 KT 35 MPH...INLAND 36H 08/1200Z...DISSIPATED $$ Forecaster Brennan

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