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Tropical Storm CRISTINA Forecast Discussion Number 5

2014-06-10 22:44:55| National Hurricane Center (East Pacific)

Issued at 200 PM PDT TUE JUN 10 2014 000 WTPZ43 KNHC 102044 TCDEP3 TROPICAL STORM CRISTINA DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032014 200 PM PDT TUE JUN 10 2014 Although inner-core thunderstorm activity has increased at times since the previous advisory, it has been unable to persist as a central dense overcast feature due to entrainment of dry mid-level air. The result is that Cristina looks much better in visible imagery than it does in IR data, and this is mainly due to the cloud pattern being comprised of mostly dissipating cirrus clouds. Having said that, microwave and conventional satellite imagery have been hinting at the formation of a 30 nmi diameter eye-like feature during the past several hours, but the cyclone has thus far been unable to sustain that development trend owing to the aforementioned dry air intrusions. The advisory intensity of 45 kt is based on a blend of satellite intensity estimates of T3.0/45 kt from both TAFB and UW-CIMSS ADT. The initial motion estimate remains 270/04 kt. Cristina is expected to continue moving generally westward and accompanied by a gradual increase in forward speed as the cyclone comes under increasing influence from a strengthening subtropical ridge that extends westward from northern Mexico to west of Baja California. By 48 hours, Cristina is forecast to turn west-northwestward around the southwestern periphery of the ridge, and that motion is expected to continue through Day 5. The NHC track forecast is just an update of the previous advisory track, and lies south and west of the consensus model TVCE due to the GFDL model having a sharp right-of-track bias from the outset of the forecast. Upper-level shear is forecast to decrease to less than 5 kt during the next 72 hours while Cristina remains over SSTs warmer than 28C. This should allow the cyclone to at least gradually strengthen for the next 24 hours or so despite the occasional dry air intrusions that will disrupt the inner core convection and the intensification process. However, if Cristina can somehow manage to close off an eye despite the relatively dry mid-level environment, then rapid strengthening during the next 24 hours or so would likely occur in such a low vertical wind shear regime. By 96 hours and beyond, the combination of much cooler sea-surface temperatures, drier and more stable air, and increasing southwesterly wind shear should produce gradual to possible rapid weakening. The NHC intensity forecast is similar to the previous advisory and follows the consensus intensity models IVCN and ICON. FORECAST POSITIONS AND MAX WINDS INIT 10/2100Z 15.5N 103.2W 45 KT 50 MPH 12H 11/0600Z 15.6N 104.4W 55 KT 65 MPH 24H 11/1800Z 15.8N 105.7W 65 KT 75 MPH 36H 12/0600Z 16.1N 107.1W 70 KT 80 MPH 48H 12/1800Z 16.7N 108.4W 70 KT 80 MPH 72H 13/1800Z 18.1N 111.0W 70 KT 80 MPH 96H 14/1800Z 19.2N 113.2W 55 KT 65 MPH 120H 15/1800Z 20.0N 115.5W 35 KT 40 MPH $$ Forecaster Stewart

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Tropical Storm CRISTINA Forecast Discussion Number 4

2014-06-10 16:42:35| National Hurricane Center (East Pacific)

Issued at 800 AM PDT TUE JUN 10 2014 000 WTPZ43 KNHC 101442 TCDEP3 TROPICAL STORM CRISTINA DISCUSSION NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032014 800 AM PDT TUE JUN 10 2014 Inner-core thunderstorm activity has increased during the past several hours and two overnight ASCAT passes indicate that the radius of maximum winds has contracted down to about 25 nmi, which is more than a 50 percent decrease from this time yesterday. The advisory intensity estimate of 40 kt is based on a blend of satellite intensity estimates of T2.9/43 kt from UW-CIMSS, T2.5/35 kt from TAFB, and T2.0/30 kt from SAB, plus the appearance of a partial mid-level eye noted in 1237 UTC TRMM microwave imagery. The initial motion estimate is 275/04 kt. Both the track forecast and reasoning remain unchanged. Cristina appears to have begun to move out of a region of weak steering currents, and the cyclone is expected to move steadily westward along the southern periphery of a building deep-layer subtropical ridge located to its north. On Day 2, the cyclone is forecast to turn west-northwestward at a faster forward speed as Cristina strengthens and becomes a more vertically deep system that will be influenced by stronger deep-layer easterly steering flow. The NHC track forecast is essentially just an update of the previous advisory track, and follows the consensus model TVCE. A large nocturnal thunderstorm complex that developed over central Mexico has ejected a large band of southward-moving cirrus outflow that appears to have temporarily increased the northerly shear across Cristina overnight. However, that thunderstorm complex has dissipated and water vapor imagery and satellite-derived winds indicate that the upper-level shear has abated over the past several hours. As a result, the environmental shear is forecast by the SHIPS model to weaken today and continue to decrease through at least the 72-hour period. This should allow for Cristina to gradually strengthen despite being embedded within a relatively dry mid-level moisture environment. By 96 hours and beyond, the cyclone is forecast to move into a thermodynamically unfavorable environment, over SSTs cooler than 26C, and encounter increasing southwesterly shear, a combination that should induce gradual to possible rapid weakening. The NHC intensity forecast is similar to the previous advisory and follows the multi-model consensus IVCN. FORECAST POSITIONS AND MAX WINDS INIT 10/1500Z 15.5N 102.9W 40 KT 45 MPH 12H 11/0000Z 15.6N 103.8W 45 KT 50 MPH 24H 11/1200Z 15.7N 105.1W 50 KT 60 MPH 36H 12/0000Z 15.9N 106.5W 60 KT 70 MPH 48H 12/1200Z 16.4N 107.9W 65 KT 75 MPH 72H 13/1200Z 17.7N 110.5W 65 KT 75 MPH 96H 14/1200Z 18.8N 112.7W 50 KT 60 MPH 120H 15/1200Z 19.8N 115.1W 35 KT 40 MPH $$ Forecaster Stewart

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Tropical Storm CRISTINA Forecast Discussion Number 3

2014-06-10 10:35:07| National Hurricane Center (East Pacific)

Issued at 200 AM PDT TUE JUN 10 2014 000 WTPZ43 KNHC 100834 TCDEP3 TROPICAL STORM CRISTINA DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032014 200 AM PDT TUE JUN 10 2014 Thunderstorm activity associated with Cristina has decreased in coverage and intensity since the evening diurnal convective minimum. Inner core convection has also become less organized, and banding is now less defined. A 0348 UTC ASCAT overpass showed around 30 kt winds, and a blend of satellite intensity estimates from TAFB and SAB is slightly lower than six hours ago. The initial intensity is held at 35 kt based on continuity from the previous advisory, though this may be a bit generous. The initial motion estimate is a slow 275/03. The track forecast is generally straightforward. Cristina is about to move out of a weak steering environment and move westward under the influence of a building mid-level ridge over northwestern Mexico at a faster forward speed. By 48 hours...the cyclone is expected to turn west- northwestward when it reaches the western end of the same mid-level ridge. The NHC track forecast is very close to the previous one and the GFS solution but not as far left as the ECMWF. UW-CIMSS shear analyses and SHIPS model output indicate light to moderate northerly shear currently over the cyclone which could be interrupting further development. However, global models show Cristina moving into a moist and generally light shear environment while moving over warm waters during the next couple of days, all of which should promote intensification to hurricane strength. In about 48 hours, the cyclone should begin to ingest a pool of drier and more stable air to the west which should bring an end to any further strengthening. An even drier and more stable environment, an increase in southwesterly shear, and marginally warm waters late in the forecast period should contribute to a weakening trend. The NHC intensity forecast is below the previous one, close to the multi-model consensus through 72 hours but near the LGEM beyond that time. FORECAST POSITIONS AND MAX WINDS INIT 10/0900Z 15.6N 102.4W 35 KT 40 MPH 12H 10/1800Z 15.6N 103.1W 40 KT 45 MPH 24H 11/0600Z 15.6N 104.4W 50 KT 60 MPH 36H 11/1800Z 15.7N 105.8W 60 KT 70 MPH 48H 12/0600Z 16.1N 107.2W 65 KT 75 MPH 72H 13/0600Z 17.3N 109.8W 65 KT 75 MPH 96H 14/0600Z 18.4N 112.1W 50 KT 60 MPH 120H 15/0600Z 19.5N 114.5W 35 KT 40 MPH $$ Forecaster Kimberlain

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Tropical Storm CRISTINA Forecast Discussion Number 2

2014-06-10 04:36:48| National Hurricane Center (East Pacific)

Issued at 800 PM PDT MON JUN 09 2014 000 WTPZ43 KNHC 100236 TCDEP3 TROPICAL STORM CRISTINA DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032014 800 PM PDT MON JUN 09 2014 Although the intensity of the deep convection has not changed significantly during the last several hours, the cyclone has better defined features with thunderstorms consolidating near the center and fragmented bands to the east and west of the center. The initial intensity estimate is 35 kt, based on a Dvorak classification from TAFB, making the cyclone Tropical Storm Cristina. Cristina has a few days to gain additional strength while the environmental factors remain generally favorable, and the models are in fairly good agreement in showing Cristina being at or near hurricane strength in 36 to 48 hours. Beyond a few days, the system is expected to move into a drier airmass with stronger southwesterly shear, and over marginal sea surface temperatures. These conditions should end the strengthening phase, and ultimately cause Cristina to weaken. The NHC intensity forecast closely follows the intensity consensus model IVCN for the first 3 days of the forecast period, and then lies lower than consensus closer to the LGEM guidance at days 4 and 5 when environmental conditions are expected to become more hostile. The storm had been drifting northwestward most of the day, but the latest satellite images suggest that Cristina is likely now moving slowly westward. This westward turn is in response to a building mid-level ridge to the northwest of the storm, and that feature should keep Cristina on a westward to west-northwestward path away from the coast of Mexico during the next several days. The NHC track forecast is close to the previous one in the short term, and then is nudged northward trending toward the latest guidance. Given the forecast track and size of the tropical cyclone, the Government of Mexico does not anticipate the need for any watches or warnings along the coast of Mexico. FORECAST POSITIONS AND MAX WINDS INIT 10/0300Z 15.5N 102.2W 35 KT 40 MPH 12H 10/1200Z 15.5N 102.9W 45 KT 50 MPH 24H 11/0000Z 15.5N 104.0W 55 KT 65 MPH 36H 11/1200Z 15.6N 105.3W 65 KT 75 MPH 48H 12/0000Z 16.0N 106.8W 70 KT 80 MPH 72H 13/0000Z 17.0N 109.2W 75 KT 85 MPH 96H 14/0000Z 18.1N 111.5W 60 KT 70 MPH 120H 15/0000Z 19.0N 113.5W 45 KT 50 MPH $$ Forecaster Cangialosi

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Tropical Depression THREE-E Forecast Discussion Number 1

2014-06-09 22:40:20| National Hurricane Center (East Pacific)

Issued at 200 PM PDT MON JUN 09 2014 000 WTPZ43 KNHC 092040 TCDEP3 TROPICAL DEPRESSION THREE-E DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032014 200 PM PDT MON JUN 09 2014 Deep convection associated with an area of low pressure to the southwest of Mexico has become much better organized during the past 12 hours, and 1554 UTC and 1640 UTC ASCAT-B and ASCAT-A overpasses, respectively, indicated that the system had uncontaminated surface winds of 30-32 kt in the northeast quadrant. Therefore, advisories are being initiated on the third tropical depression of the eastern North Pacific season. The initial intensity is set at 30 kt based on the ASCAT data and satellite estimates of T2.5/35 kt from TAFB and T1.5/25 kt from SAB. The initial motion estimate is an uncertain 270/04 kt, based primarily on microwave satellite data and ASCAT wind data. The cyclone is expected to remain south of a deep-layer subtropical ridge that extends westward from northern Mexico to Baja California and into the eastern Pacific. The global and regional models are in excellent agreement on a westward to west-northwestward motion throughout the forecast period, and the official forecast track is similar to but slightly faster the consensus model TVCE. Although the cloud structure of the depression has improved markedly in visible imagery since this morning, several microwave images indicate that the low-level and mid-level circulations are not yet juxtaposed. Furthermore, ASCAT wind data suggest that the low-level circulation is slightly elongated east-west, and a pronounced dry slot coming off of the mountains of Mexico is also evident in visible and microwave satellite data in the western semicircle. As a result, only gradual rather than rapid strengthening is forecast for the next 24-48 hours while the cyclone remains over warm water and in a low environmental wind shear. By 96 hours, cooler SSTs less than 26C, increasing southwesterly shear, and drier mid-level air are expected to produce steady weakening. The official intensity forecast is similar to the intensity consensus model ICON. Given the forecast track and size of the tropical cyclone, the Government of Mexico does not anticipate the need for any watches or warnings along the coast of Mexico. FORECAST POSITIONS AND MAX WINDS INIT 09/2100Z 15.4N 102.0W 30 KT 35 MPH 12H 10/0600Z 15.5N 102.8W 40 KT 45 MPH 24H 10/1800Z 15.6N 103.8W 50 KT 60 MPH 36H 11/0600Z 15.7N 105.1W 60 KT 70 MPH 48H 11/1800Z 15.9N 106.6W 70 KT 80 MPH 72H 12/1800Z 16.6N 109.1W 70 KT 80 MPH 96H 13/1800Z 17.6N 112.1W 60 KT 70 MPH 120H 14/1800Z 18.7N 114.3W 40 KT 45 MPH $$ Forecaster Stewart

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