Home › discussion
 

Keywords :   


Tag: discussion

Hurricane GUILLERMO Forecast Discussion Number 6

2015-07-31 10:32:17| National Hurricane Center (East Pacific)

Issued at 200 AM PDT FRI JUL 31 2015 000 WTPZ44 KNHC 310832 TCDEP4 HURRICANE GUILLERMO DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092015 200 AM PDT FRI JUL 31 2015 Guillermo's cloud pattern has continued to become better organized, with well-defined convective banding and a fairly symmetric upper-level outflow pattern. A recent GMI microwave image showed a nearly closed low-level eyewall. The current intensity is set to 70 kt, based on a blend of subjective and objective Dvorak estimates. This makes Guillermo the fifth hurricane of the 2015 eastern North Pacific season. Given that the hurricane should be moving over warm waters, and in a moist mid-level environment with moderate shear, further strengthening is likely. The official intensity forecast is near or above the latest model consensus. Since the SHIPS-RI index still indicates a significant probability of rapid intensification over the next 24 hours, the NHC forecast could be conservative. There is considerable uncertainty in the intensity forecast beyond 48-72 hours, since Guillermo could encounter stronger shear, depending mainly on how far north the cyclone moves late in the forecast period. Based on geostationary and microwave center fixes, the initial motion is west-northwestward or 300/14 kt. A mid-tropospheric ridge to the north of the tropical cyclone should maintain the west-northwestward motion for the next several days. In 48-72 hours, Guillermo should encounter a weakness in the ridge which will likely cause some slowing of forward speed. However most of the guidance does not show much of a turn to the right in response to this weakness. The official track forecast is close to a consensus of the latest GFS and ECMWF solutions, with the former model to the north of the latter near the end of the period. This is similar to the previous NHC track. FORECAST POSITIONS AND MAX WINDS INIT 31/0900Z 11.5N 130.6W 70 KT 80 MPH 12H 31/1800Z 12.1N 132.8W 80 KT 90 MPH 24H 01/0600Z 12.7N 135.7W 90 KT 105 MPH 36H 01/1800Z 13.3N 138.4W 95 KT 110 MPH 48H 02/0600Z 14.1N 140.6W 95 KT 110 MPH 72H 03/0600Z 15.5N 144.0W 80 KT 90 MPH 96H 04/0600Z 16.5N 146.5W 70 KT 80 MPH 120H 05/0600Z 17.5N 150.0W 55 KT 65 MPH $$ Forecaster Pasch

Tags: number discussion forecast hurricane

 

Tropical Storm GUILLERMO Forecast Discussion Number 5

2015-07-31 04:47:11| National Hurricane Center (East Pacific)

Issued at 800 PM PDT THU JUL 30 2015 000 WTPZ44 KNHC 310247 TCDEP4 TROPICAL STORM GUILLERMO DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092015 800 PM PDT THU JUL 30 2015 Microwave and conventional satellite imagery indicate that Guillermo is continuing to become better organized. The microwave imagery shows a developing eye, which has occasionally appeared in visible and infrared imagery. Satellite intensity estimates are 55 kt from TAFB and SAB, and the latest intensity estimate from the CIMSS Advanced Dvorak Technique is 65 kt. Based on these, the initial intensity is increased to 60 kt. Guillermo has turned to the right during the past several hours with the initial motion now 305/12. Other than that, there is little change in the forecast philosophy. The subtropical ridge north of the storm is forecast to strengthen slightly, causing Guillermo to accelerate west-northwestward during the next 36 hours. After that time, a mid- to upper-level low well west of California is expected to produce a break in the ridge, which should cause the cyclone to slow down and turn more northward by day 5. The forecast track from 0 to 72 hours has been adjusted northward based on the initial position and motion. After 72 hours, the forecast guidance has again shifted to the left or west, and the forecast track has also been moved in that direction. However, this part of the forecast lies to the north of the various consensus models. The developing eye seen in microwave imagery shows that the structure of Guillermo is conducive for additional rapid intensification. Also, the Rapid Intensification Index of the SHIPS model shows a 50 percent chance of a 30 kt increase in intensity during the next 24 hours. Based on this, the intensities during the first 48 hours of the forecast have been increased over those of the previous advisory, and this part of the forecast lies near the upper edge of the intensity guidance. After 48 hours, the cyclone will move over decreasing sea surface temperatures and possibly encounter westerly vertical wind shear. This combination is expected to cause the cyclone to weaken below hurricane strength by 120 hours. It should be noted that the early part of the intensity forecast is of low confidence due to the uncertainties associated with rapid intensification, and the later part is of low confidence due to uncertainties in how much shear Guillermo will encounter. FORECAST POSITIONS AND MAX WINDS INIT 31/0300Z 10.8N 129.3W 60 KT 70 MPH 12H 31/1200Z 11.4N 131.4W 70 KT 80 MPH 24H 01/0000Z 12.3N 134.5W 80 KT 90 MPH 36H 01/1200Z 13.1N 137.5W 90 KT 105 MPH 48H 02/0000Z 13.9N 139.8W 95 KT 110 MPH 72H 03/0000Z 15.5N 143.5W 85 KT 100 MPH 96H 04/0000Z 16.5N 146.5W 70 KT 80 MPH 120H 05/0000Z 18.0N 149.5W 55 KT 65 MPH $$ Forecaster Beven

Tags: number discussion storm tropical

 
 

Tropical Storm GUILLERMO Forecast Discussion Number 4

2015-07-30 22:32:05| National Hurricane Center (East Pacific)

Issued at 200 PM PDT THU JUL 30 2015 000 WTPZ44 KNHC 302032 TCDEP4 TROPICAL STORM GUILLERMO DISCUSSION NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092015 200 PM PDT THU JUL 30 2015 Guillermo is quickly becoming better organized, and both microwave and visible imagery suggest that the cyclone is developing a ring of inner core convection. Dvorak classifications at 1800 UTC were T3.0/45 kt from both TAFB and SAB, but given the quickly improving convective structure, the advisory intensity is set at 50 kt. This is close to the latest UW-CIMSS ADT estimate of T3.4/53 kt. The upper-level outflow of Guillermo continues to expand, and the storm is over very warm waters of around 29 degrees Celsius. Global model guidance indicates that Guillermo should remain in a light-shear environment for at least another 3 days, while also remaining over warm water and in a moisture-laden atmosphere. Therefore, continued strengthening is likely for the next 48 hours, and Guillermo could become a hurricane within the next 12-24 hours. Gradual weakening is forecast from day 3 through 5 due to stronger upper-level westerly winds which could affect the cyclone. The statistical-dynamical guidance continues to show only modest strengthening--barely taking Guillermo to hurricane status--but this scenario seems low given the seemingly favorable environment. The NHC official intensity forecast remains closer to the higher dynamical guidance and is largely unchanged from the previous forecast. The subtropical ridge is steering Guillermo west-northwestward, or 295/12 kt. The ridge is forecast to strengthen slightly, causing Guillermo to accelerate during the next 36 hours. After that time, a mid- to upper-level low well west of California is expected to produce a break in the ridge, which should cause the cyclone to slow down and turn northwestward by day 5. The latest track guidance ended up lying to the west of the previous official forecast track, and the updated NHC track has therefore been shifted a bit to the left, especially after 48 hours. FORECAST POSITIONS AND MAX WINDS INIT 30/2100Z 9.8N 128.4W 50 KT 60 MPH 12H 31/0600Z 10.6N 130.6W 60 KT 70 MPH 24H 31/1800Z 11.5N 133.7W 70 KT 80 MPH 36H 01/0600Z 12.4N 136.8W 75 KT 85 MPH 48H 01/1800Z 13.2N 139.4W 80 KT 90 MPH 72H 02/1800Z 14.9N 143.3W 75 KT 85 MPH 96H 03/1800Z 16.5N 146.0W 65 KT 75 MPH 120H 04/1800Z 18.0N 148.5W 55 KT 65 MPH $$ Forecaster Berg

Tags: number discussion storm tropical

 

Post-Tropical Cyclone EIGHT-E Forecast Discussion Number 12

2015-07-30 16:38:10| National Hurricane Center (East Pacific)

Issued at 800 AM PDT THU JUL 30 2015 000 WTPZ43 KNHC 301438 TCDEP3 POST-TROPICAL CYCLONE EIGHT-E DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL EP082015 800 AM PDT THU JUL 30 2015 Tropical Depression Eight-E has been devoid of organized deep convection near the center for more than 18 hours, except for an isolated thunderstorm that has recently developed just south of the well-defined circulation center. However, the main band of convection is located in the northeastern quadrant, but it is more than 200 n mi from the center. Therefore, this system no longer meets the criteria of a tropical cyclone; it is being designated as a remnant low, and advisories are being discontinued at this time. The initial intensity remains at 25 kt based on an earlier RapidSCAT overpass. Since the remnant low is heading toward a more hostile environment, the new NHC official forecast is similar to the previous advisory, calling for dissipation in about 24 hours. The remnant low is moving at 270/11 kt. This general motion should continue today, followed by a turn toward the west-southwest by Friday morning. The remnant low is forecast to cross into the Central Pacific Hurricane Center's area of responsibility within the next couple of hours. For additional information on this remnant low please see High Seas Forecasts issued by the National Weather Service, under AWIPS header NFDHSFEPI and WMO header FZPN02 KWBC. FORECAST POSITIONS AND MAX WINDS INIT 30/1500Z 16.5N 139.4W 25 KT 30 MPH...POST-TROP/REMNT LOW 12H 31/0000Z 16.3N 141.8W 25 KT 30 MPH...POST-TROP/REMNT LOW 24H 31/1200Z...DISSIPATED $$ Forecaster Stewart

Tags: number discussion forecast cyclone

 

Tropical Storm GUILLERMO Forecast Discussion Number 3

2015-07-30 16:36:37| National Hurricane Center (East Pacific)

Issued at 800 AM PDT THU JUL 30 2015 000 WTPZ44 KNHC 301436 TCDEP4 TROPICAL STORM GUILLERMO DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092015 800 AM PDT THU JUL 30 2015 Guillermo's convective pattern continues to improve, with a solid band curving about half way around the center of circulation. Dvorak classifications were T3.0/45 kt from TAFB and T2.5/35 kt from SAB, and the initial intensity is therefore set at 40 kt. This could be somewhat conservative, given that the latest objective ADTs are around 45 kt. The environment ahead of Guillermo looks plenty favorable for continued strengthening. Upper-level outflow is expanding around the cyclone, and Guillermo should remain in a light-shear environment for at least the next 3-4 days. In addition, sea surface temperatures are about 29 degrees C, and the atmosphere is moist and unstable. Additional strengthening is anticipated during the next few days, and there remains a 1 in 3 chance of rapid intensification during the next 24 hours. Given the favorable environment, the official intensity forecast is a little above the intensity consensus for the entire forecast period. It should be noted that the HWRF model shows a stronger hurricane than is indicated in the official forecast, bringing Guillermo to category 2 strength in about 3 days. Some weakening should occur by days 4 and 5, mainly due to increased shear and lower oceanic heat content. Guillermo is moving west-northwestward, or 290/11 kt, to the south of the subtropical ridge. The global models indicate that a mid- to upper-level low located about 1000 miles west of southern California will deepen and amplify during the next few days, which should produce a break in the subtropical ridge. The track models are in good agreement during the first 48 hours, and most of the spread beyond that time is due to speed differences. An overall westward shift in the guidance envelope necessitated an adjustment to the official track forecast from 48 hours and beyond, and it lies close to a consensus of the GFS and ECMWF models. FORECAST POSITIONS AND MAX WINDS INIT 30/1500Z 9.1N 127.5W 40 KT 45 MPH 12H 31/0000Z 9.9N 129.5W 55 KT 65 MPH 24H 31/1200Z 11.0N 132.5W 65 KT 75 MPH 36H 01/0000Z 12.0N 135.7W 70 KT 80 MPH 48H 01/1200Z 12.8N 138.6W 80 KT 90 MPH 72H 02/1200Z 14.6N 142.8W 80 KT 90 MPH 96H 03/1200Z 16.0N 145.5W 70 KT 80 MPH 120H 04/1200Z 18.0N 148.0W 60 KT 70 MPH $$ Forecaster Berg

Tags: number discussion storm tropical

 

Sites : [997] [998] [999] [1000] [1001] [1002] [1003] [1004] [1005] [1006] [1007] [1008] [1009] [1010] [1011] [1012] [1013] [1014] [1015] [1016] next »