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Tropical Storm CRISTINA Forecast Discussion Number 21

2014-06-14 16:35:16| National Hurricane Center (East Pacific)

Issued at 800 AM PDT SAT JUN 14 2014 000 WTPZ43 KNHC 141435 TCDEP3 TROPICAL STORM CRISTINA DISCUSSION NUMBER 21 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032014 800 AM PDT SAT JUN 14 2014 Cristina's convective organization is degrading quickly, with the low-level center located near the southwestern edge of an elongating convective band. A blend of the Final-T and CI numbers from TAFB, SAB, and the ADT support downgrading Cristina to a 60-kt tropical storm on this advisory. Vertical shear will continue to increase during the next day or two, and Cristina will also be moving over sub-26C water in about 12-24 hours. Therefore, steady weakening is forecast to continue, and the cyclone will likely become a remnant low in 36-48 hours and dissipate by day 5. The NHC intensity forecast favors a fairly quick weakening rate and is closest to the Florida State Superensemble and the HWRF model. Cristina has slowed down a bit, and the initial motion is 310/5 kt. Now that vertical shear is decoupling the system, the cyclone is likely to turn toward the west-northwest later today and maintain that heading through 48 hours. After that time, a break in the subtropical ridge should allow the remnant low to turn toward the north-northwest before it dissipates. This northward trend has been observed in several model cycles, and the NHC track forecast has again been shifted northward on days 3 and 4. FORECAST POSITIONS AND MAX WINDS INIT 14/1500Z 19.4N 111.4W 60 KT 70 MPH 12H 15/0000Z 19.8N 112.2W 45 KT 50 MPH 24H 15/1200Z 20.2N 113.1W 35 KT 40 MPH 36H 16/0000Z 20.6N 114.0W 30 KT 35 MPH 48H 16/1200Z 21.0N 115.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 17/1200Z 22.0N 116.5W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 18/1200Z 23.0N 117.0W 15 KT 15 MPH...POST-TROP/REMNT LOW 120H 19/1200Z...DISSIPATED $$ Forecaster Berg

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Hurricane CRISTINA Forecast Discussion Number 19

2014-06-14 04:38:15| National Hurricane Center (East Pacific)

Issued at 800 PM PDT FRI JUN 13 2014 000 WTPZ43 KNHC 140238 TCDEP3 HURRICANE CRISTINA DISCUSSION NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032014 800 PM PDT FRI JUN 13 2014 Conventional satellite imagery shows that Cristina's inner core convection has become somewhat better organized and colder than six hours ago. The eye is also slightly better defined and warmer, though it was cloud-filled in last-light visible images. A 0045 UTC SSMIS overpass revealed that a new inner eyewall had developed but was partially open to the southwest. Although Dvorak CI- and Final-T numbers were a consensus 4.5/77 kt at 00z, the initial intensity is kept at 80 kt, owing to the slight increase in organization of the the cloud pattern since the last advisory. Despite the recent uptick in organization, gradual weakening is indicated by the intensity guidance during the day or two as Cristina encounters increasing southwesterly shear and moves over cooler waters. Rapid weakening is likely by 48 hours, when the cyclone reaches a hostile environment of sea surface temperatures lower than 25C, greater than 20 kt of southwesterly shear, and a substantially drier and more stable air mass. The NHC intensity forecast is little changed from the previous one except to show remnant low status a day sooner. The initial motion estimate is 310/06. Global models show Cristina being steered around the southwestern periphery of a subtropical ridge over northwestern Mexico in the short term. This feature is forecast to weaken during the next couple of days as a longwave trough becomes established over the western United States and extreme northern Mexico. This pattern should cause the forward speed of the cyclone to decrease while the the circulation weakens and becomes more shallow. The shallow vortex should turn westward by 72 hours and move little as it becomes embedded in region of weak low-level steering. Given the good model agreement, the NHC forecast is nearly identical to the previous one and very near the multi-model consensus. FORECAST POSITIONS AND MAX WINDS INIT 14/0300Z 18.9N 110.7W 80 KT 90 MPH 12H 14/1200Z 19.3N 111.4W 70 KT 80 MPH 24H 15/0000Z 19.8N 112.2W 60 KT 70 MPH 36H 15/1200Z 20.1N 113.0W 50 KT 60 MPH 48H 16/0000Z 20.4N 113.8W 35 KT 40 MPH 72H 17/0000Z 21.0N 115.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 18/0000Z 21.2N 117.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 19/0000Z 21.2N 118.0W 15 KT 15 MPH...POST-TROP/REMNT LOW $$ Forecaster Kimberlain

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Hurricane CRISTINA Forecast Discussion Number 18

2014-06-13 22:33:23| National Hurricane Center (East Pacific)

Issued at 200 PM PDT FRI JUN 13 2014 000 WTPZ43 KNHC 132033 TCDEP3 HURRICANE CRISTINA DISCUSSION NUMBER 18 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032014 200 PM PDT FRI JUN 13 2014 A 1657 UTC AMSU pass suggests that Cristina's eyewall replacement is probably almost complete, and coincidentally, visible satellite images show a ragged eye trying to re-form. The convective pattern is somewhat lopsided, however, and objective ADT estimates have continued to slowly decrease. Based on the latest Dvorak estimates, the initial intensity is set at 80 kt. Now that the eyewall replacement appears complete, it is not out of the question that Cristina could re-intensify a bit or at least maintain its intensity in the short term while environmental conditions remain relatively favorable. From this point forward, however, vertical shear will be gradually increasing and sea surface temperatures will be decreasing. Therefore, the gradual weakening trend currently in progress is expected to continue during the next three days, with Cristina likely to become a remnant low by day 4. The NHC intensity forecast is between the intensity consensus and the Florida State Superensemble, which dissipates Cristina by day 3. Cristina is still moving northwestward at about 7 kt. The cyclone is expected to begin slowing down in about 24 hours when the mid- level ridge to its north weakens. Low- to mid-level ridging will then steer Cristina west-northwestward through the remainder of the forecast period. The guidance is in fairly good agreement on Cristina's future track, and no significant changes to the NHC forecast were required on this advisory cycle. FORECAST POSITIONS AND MAX WINDS INIT 13/2100Z 18.5N 110.2W 80 KT 90 MPH 12H 14/0600Z 19.1N 111.0W 70 KT 80 MPH 24H 14/1800Z 19.6N 111.8W 60 KT 70 MPH 36H 15/0600Z 19.9N 112.5W 50 KT 60 MPH 48H 15/1800Z 20.3N 113.3W 40 KT 45 MPH 72H 16/1800Z 21.0N 115.0W 30 KT 35 MPH 96H 17/1800Z 21.5N 116.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 18/1800Z 21.5N 117.5W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Berg

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Hurricane CRISTINA Forecast Discussion Number 17

2014-06-13 16:33:11| National Hurricane Center (East Pacific)

Issued at 800 AM PDT FRI JUN 13 2014 000 WTPZ43 KNHC 131433 TCDEP3 HURRICANE CRISTINA DISCUSSION NUMBER 17 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032014 800 AM PDT FRI JUN 13 2014 Cristina appears to be in the latter stages of an eyewall replacement. A small part of the original eyewall is surrounded by an elongated spiral band, and the eye, as seen in microwave images, has expanded to 25-30 n mi wide. The satellite intensity estimates are still suggesting an overall downward trend, and the initial intensity is lowered to 85 kt based on a blend of the Final-T and Current Intensity numbers from TAFB, SAB, and the ADT. Cristina is approaching a tight sea surface temperature gradient, and the cyclone probably has another 36 hours or so before it moves over water colder than 26C. In addition, upper-level winds are likely to become more hostile in about 24 hours with the approach of a sharp upper-level trough from the west. Therefore, it is unlikely that Cristina will recover much after the eyewall replacement, and continued steady weakening is expected during the entire forecast period. The new NHC forecast is mainly an update of the previous one and is close to the intensity consensus during the first 24 hours and then a bit lower between 36-72 hours. A mid-level ridge located over northwestern Mexico continues to steer Cristina northwestward at about 7 kt. This motion should continue for another 24 hours while the cyclone remains a hurricane or strong tropical storm. The weakening system is then expected to turn west-northwestward by 36 hours. The track guidance once again shifted a little to the north on this advisory cycle, and the new NHC track forecast is also moved in that direction for much of the forecast period. FORECAST POSITIONS AND MAX WINDS INIT 13/1500Z 18.0N 109.6W 85 KT 100 MPH 12H 14/0000Z 18.7N 110.5W 75 KT 85 MPH 24H 14/1200Z 19.4N 111.5W 65 KT 75 MPH 36H 15/0000Z 19.8N 112.3W 55 KT 65 MPH 48H 15/1200Z 20.1N 113.1W 45 KT 50 MPH 72H 16/1200Z 20.5N 115.0W 35 KT 40 MPH 96H 17/1200Z 21.0N 116.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 18/1200Z 21.5N 117.5W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Berg

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Hurricane CRISTINA Forecast Discussion Number 16

2014-06-13 10:38:09| National Hurricane Center (East Pacific)

Issued at 200 AM PDT FRI JUN 13 2014 000 WTPZ43 KNHC 130838 TCDEP3 HURRICANE CRISTINA DISCUSSION NUMBER 16 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032014 200 AM PDT FRI JUN 13 2014 After going through a remarkable rapid intensification yesterday, Cristina has now rapidly weakened at a similar rate. Microwave imagery suggest that the eyewall is about 50 percent open, and only occasional hints of an eye can be seen on conventional satellite data. The initial wind speed is lowered to 90 kt as a blend of the Dvorak estimates. However this value is more uncertain than normal owing to a rather large spread in the satellite intensity estimates from various agencies. Decreasing SSTS, along with increasing shear and dry air aloft, should generally continue to weaken Cristina. Most of the models do suggest a slower weakening rate than what has recently been observed, which seems reasonable since the environment isn't extremely hostile. The NHC intensity forecast is reduced from the previous one, mostly to account for the steep drop in the initial wind speed, and is close to the intensity consensus. Transition into a remnant low seems likely in about 3-4 days when Cristina is surrounded by very dry air and over cool waters. The cyclone is now moving to the northwest at about 7 kt. A northwestward to west-northwestward motion is expected during the next day or two while Cristina is steered by a mid-level ridge over northern Mexico. After that time, the weakened storm should turn westward, steered primarily by the low-level flow. The only notable change to the track guidance on this cycle is that Cristina continues the west-northwestward motion for a little longer before taking the westward turn. The NHC track forecast is adjusted slightly to the north beyond 48 hours, following the trend in the latest guidance, but is otherwise virtually unchanged. FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 17.7N 109.1W 90 KT 105 MPH 12H 13/1800Z 18.3N 110.0W 80 KT 90 MPH 24H 14/0600Z 19.0N 111.1W 70 KT 80 MPH 36H 14/1800Z 19.5N 112.0W 60 KT 70 MPH 48H 15/0600Z 19.8N 112.9W 50 KT 60 MPH 72H 16/0600Z 20.2N 114.6W 35 KT 40 MPH 96H 17/0600Z 20.5N 116.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 18/0600Z 20.5N 118.5W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Blake

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