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Hurricane CELIA Forecast Discussion Number 21

2016-07-11 22:42:35| National Hurricane Center (East Pacific)

Issued at 200 PM PDT MON JUL 11 2016 000 WTPZ44 KNHC 112042 TCDEP4 HURRICANE CELIA DISCUSSION NUMBER 21 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016 200 PM PDT MON JUL 11 2016 During the past 6 h, the inner-core region of Celia has undergone multiple evolutions from a banding eye into a large eye that was more representative of an annular hurricane to what has now become a 20-nmi cloud-filled eye. Subjective Dvorak current intensity (CI) estimates remain T4.5/77 kt from TAFB and SAB, and CIRA and CIMSS AMSU objective intensity estimates were 87 kt and 86 kt at 1435Z, respectively. Since those subjective and objective estimates were obtained, the inner-core convection has increased markedly, especially during the past few hours, with tightly coiled convective bands now concentrated within mainly 70 nmi of the center. Based on the improved satellite appearance, the initial intensity has been increased to 85 kt. The initial motion estimate is 280/08 kt. As anticipated, Celia has slowed its forward motion as it approaches a developing weakness in the subtropical ridge. A turn toward the west-northwest later tonight is expected as Celia begins to move into the developing weakness in the ridge. The shortwave trough that is inducing this weakness is forecast to weaken in 48-72 h and lift out to the north or northeast. This will allow the ridge to re-strengthen and gradually nudge Celia back on a more westward track in the 72-120 h period. The latest NHC track guidance continues to be in excellent agreement with very little spread in the models, and the new forecast track is essentially just an update of the previous advisory track, and lies along the southern edge of the guidance envelope. The center of Celia is currently passing over 25.5 deg C SSTs based on reports from drifting buoy 43540, which is about 2 deg C cooler than the SHIPS intensity model is indicating. Having said that, the cooler water doesn't appear to have negatively affected Celia today, perhaps due to the proximity to warmer water and deeper instability to the south. However, by 12 h and beyond, Celia will be moving over a large field of sub-26 deg C SSTs and into an extensive region of stable stratocumulus clouds, and the decreasing instability is expected to induce steady weakening throughout the remainder of the forecast period. However, with the vertical shear forecast to remain low, Celia is expected to still be a tropical cyclone when it crosses 140W longitude and moves into the Central Pacific basin in 84-96 h. The new intensity forecast is similar to the previous advisory, and closely follows the consensus model IVCN. FORECAST POSITIONS AND MAX WINDS INIT 11/2100Z 15.2N 126.2W 85 KT 100 MPH 12H 12/0600Z 15.7N 127.6W 85 KT 100 MPH 24H 12/1800Z 16.6N 129.4W 80 KT 90 MPH 36H 13/0600Z 17.7N 131.2W 70 KT 80 MPH 48H 13/1800Z 18.8N 133.2W 60 KT 70 MPH 72H 14/1800Z 20.5N 137.4W 50 KT 60 MPH 96H 15/1800Z 21.3N 142.0W 40 KT 45 MPH 120H 16/1800Z 21.8N 147.2W 35 KT 40 MPH $$ Forecaster Stewart

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Significant Changes to the Discussion Draft

2016-07-11 22:39:48| PortlandOnline

Handout summarizing significant changes between the Discussion Draft and the current Proposed Draft PDF Document, 1,139kbCategory: CC2035 Proposed Draft (June 2016)

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Hurricane CELIA Forecast Discussion Number 20

2016-07-11 16:41:04| National Hurricane Center (East Pacific)

Issued at 800 AM PDT MON JUL 11 2016 000 WTPZ44 KNHC 111440 TCDEP4 HURRICANE CELIA DISCUSSION NUMBER 20 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016 800 AM PDT MON JUL 11 2016 After developing what had been a decent looking eye with a diameter of about 20 nmi, dry air has once again penetrated into the inner-core region and has eroded most of the eyewall convection. Satellite current intensity estimates range from T4.5/77 kt from TAFB and SAB to as high as T5.4/100 kt from UW-CIMSS ADT. Given the ragged-appearing inner-core region in the last few images, the intensity is only raised to 80 kt for this advisory, which is consistent with a 1200 UTC UW-CIMSS SATCON consensus of 82 kt. The initial motion estimate is 275/11 kt. A westward motion is expected to continue today, followed by a turn toward the west-northwest late tonight as Celia begins to move into a developing weakness in the subtropical ridge. This weakness will be created by a narrow mid-level trough along 130W longitude that is digging southward as noted in water vapor imagery. The shortwave trough is forecast to weaken by 72 h and lift out to the north or northeast, which will allow the ridge to rebuild and force Celia back on a more westward track on days 3-5. Similar to the previous advisory, the NHC track model guidance remains in excellent agreement on this scenario and is tightly packed around the previous forecast track. As a result, the new forecast track is essentially just an extension of the previous advisory track, and lies just south of the TVCN consensus model. Celia likely only has another 12 hours or so to strengthen while the hurricane remains over SSTs above 26.5 deg C. The overall mid-level environment is fairly moist and the vertical shear is expected to remain light, which should favor some additional intensification. By 36 hours, however, Celia will be moving over sub-26C SSTs, which should induce slow but steady weakening through the remainder of the forecast period. However, since the vertical wind shear is expected to remain low, Celia is forecast to still be a tropical cyclone when it crosses 140W longitude and moves into the Central Pacific basin in about 96 hours. The new intensity forecast is similar to the previous advisory, and lies above all of the intensity guidance through 36 h, and then lies near or below the guidance after that during the weakening phase. FORECAST POSITIONS AND MAX WINDS INIT 11/1500Z 15.1N 125.5W 80 KT 90 MPH 12H 12/0000Z 15.5N 126.9W 90 KT 105 MPH 24H 12/1200Z 16.1N 128.7W 85 KT 100 MPH 36H 13/0000Z 17.1N 130.4W 80 KT 90 MPH 48H 13/1200Z 18.2N 132.2W 70 KT 80 MPH 72H 14/1200Z 20.1N 136.2W 60 KT 70 MPH 96H 15/1200Z 21.1N 140.7W 50 KT 60 MPH 120H 16/1200Z 21.6N 145.8W 40 KT 45 MPH $$ Forecaster Stewart

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Hurricane CELIA Forecast Discussion Number 19

2016-07-11 10:33:48| National Hurricane Center (East Pacific)

Issued at 200 AM PDT MON JUL 11 2016 000 WTPZ44 KNHC 110833 TCDEP4 HURRICANE CELIA DISCUSSION NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016 200 AM PDT MON JUL 11 2016 Celia still has a somewhat ragged satellite appearance tonight. The deepest convection is located in a broken ring around a ragged intermittent eye and in a band well east of the center. TAFB and SAB Dvorak estimates at 06Z were T4.5/77 kt, and the initial intensity is set to 75 kt for this advisory. Additional slow strengthening seems likely for the next day or so while Celia moves over SSTs above 26C. After that time the waters will cool, which should result in a slow weakening through the remainder of the forecast period since the shear will remain low. The new NHC forecast is similar to the previous one, showing a peak of 90 kt in about 24 h, and this is above all of the intensity guidance. During the weakening phase, the NHC forecast lies between the stronger SHIPS model and the weaker LGEM. The hurricane is moving westward at 11 kt. A turn toward the west-northwest is forecast in about 24 hours as Celia reaches the southwestern edge of a mid-level ridge. By the end of the period, the ridge should rebuild to the north, resulting in the track bending back toward the west. Overall, the track model guidance is in good agreement on this scenario. For this cycle, the NHC forecast has been adjusted a bit to the north, but lies south of the latest TVCN multi-model consensus aid. An ASCAT-B pass from around 0520Z was used to adjust the initial 34-kt and 50-kt wind radii. FORECAST POSITIONS AND MAX WINDS INIT 11/0900Z 15.0N 124.5W 75 KT 85 MPH 12H 11/1800Z 15.1N 126.0W 85 KT 100 MPH 24H 12/0600Z 15.7N 127.9W 90 KT 105 MPH 36H 12/1800Z 16.5N 129.5W 85 KT 100 MPH 48H 13/0600Z 17.5N 131.3W 80 KT 90 MPH 72H 14/0600Z 19.6N 135.1W 70 KT 80 MPH 96H 15/0600Z 21.0N 139.5W 55 KT 65 MPH 120H 16/0600Z 21.5N 144.5W 45 KT 50 MPH $$ Forecaster Brennan

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Hurricane CELIA Forecast Discussion Number 18

2016-07-11 04:37:29| National Hurricane Center (East Pacific)

Issued at 800 PM PDT SUN JUL 10 2016 000 WTPZ44 KNHC 110237 TCDEP4 HURRICANE CELIA DISCUSSION NUMBER 18 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042016 800 PM PDT SUN JUL 10 2016 Celia has well-defined curved banding features, but the convection is not very deep at this time. A fairly symmetric upper-level outflow pattern is evident, consistent with a low-shear environment. The Dvorak data T-number from TAFB was slightly lower and that from SAB was unchanged, and the current intensity estimate is kept at 70 kt for this advisory. Sea surface temperatures should be marginally supportive for strengthening for another 24 hours or so, and thereafter slightly cooler waters are expected to cause a weakening trend to commence. As noted in the earlier advisory the shear over the tropical cyclone is likely to remain low for the next several days, and this should keep the rate of weakening rather slow. The official intensity forecast is very close to the latest Decay-SHIPS guidance. There has been no significant change to the motion, which is estimated to be 270/11 kt. The track forecast seems to be fairly straightforward and there is little change to the prognostic reasoning. Celia will be nearing the western periphery of a mid-tropospheric subtropical ridge, and this should cause the motion to gradually bend toward the west-northwest during the next couple of days. Afterwards, the subtropical ridge rebuilds to the north of the cyclone resulting in a turn back toward the west by the end of the forecast period. The NHC track forecast is very similar to that from the previous advisory, and is also close to the dynamical model consensus. This is between the latest GFS and ECMWF solutions. FORECAST POSITIONS AND MAX WINDS INIT 11/0300Z 15.0N 123.5W 70 KT 80 MPH 12H 11/1200Z 15.1N 125.2W 80 KT 90 MPH 24H 12/0000Z 15.5N 127.3W 90 KT 105 MPH 36H 12/1200Z 16.2N 129.2W 90 KT 105 MPH 48H 13/0000Z 17.0N 130.9W 85 KT 100 MPH 72H 14/0000Z 18.9N 134.6W 75 KT 85 MPH 96H 15/0000Z 20.7N 138.8W 60 KT 70 MPH 120H 16/0000Z 21.5N 143.5W 50 KT 60 MPH $$ Forecaster Pasch

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