Home discussion
 

Keywords :   


Tag: discussion

Tropical Storm Douglas Forecast Discussion Number 5

2020-07-21 16:38:44| National Hurricane Center (East Pacific)

Issued at 500 AM HST Tue Jul 21 2020 000 WTPZ43 KNHC 211438 TCDEP3 Tropical Storm Douglas Discussion Number 5 NWS National Hurricane Center Miami FL EP082020 500 AM HST Tue Jul 21 2020 A recent SSMIS microwave pass indicated that Douglas's low-level center is located very near the head of a broken band of convection which curls around the southern, western, and northern side of the circulation. This center is also now embedded beneath a Central Dense overcast in infrared imagery, near an area of cold overshooting cloud tops. TAFB and SAB Dvorak classifications have both risen to T3.5, and Douglas's initial intensity is therefore raised to 55 kt. Douglas continues to dip west-southwestward, or 255/13 kt, due to strong mid-level ridging to its north. A mid- to upper-level low located northeast of the Hawaiian Islands is forecast to retrograde westward over the next few days, which will allow the ridge to take on a more east-west orientation. As a result, Douglas is expected to turn westward later today and then move west-northwestward beginning overnight Wednesday into the weekend. The track guidance all agrees on this scenario, but there are some speed differences, bookended by slower GFS and HWRF solutions and a faster ECMWF solution. Overall, however, the new NHC forecast remains very close to the multi-model consensus aids, and no significant changes were made compared to the previous forecast, except maybe a slight northward adjustment on days 4 and 5. The low-shear, warm sea surface temperature environment within which Douglas is moving is a recipe for continued strengthening, potentially at a rapid rate, for the next 48 hours. The intensity guidance has been trending higher, and the latest SHIPS Rapid Intensification (RI) indices are highlighting the increased chance of RI. For example, there is currently a 50/50 shot that Douglas's winds will increase by 25 kt within the next 24 hours, and a 40-50 percent chance of a 30-kt increase during that period. Based on this guidance, the new HCCA and Florida State Superensemble solutions, and the intensity consensus, the NHC intensity forecast has been increased from the previous cycle and now shows Douglas becoming a hurricane later today with a higher peak occurring in about 2 days. Since oceanic heat content falls to zero along Douglas's path by day 3, some gradual weakening is shown in the latter stages of the forecast. FORECAST POSITIONS AND MAX WINDS INIT 21/1500Z 12.4N 124.2W 55 KT 65 MPH 12H 22/0000Z 12.1N 126.0W 70 KT 80 MPH 24H 22/1200Z 12.1N 128.5W 80 KT 90 MPH 36H 23/0000Z 12.6N 131.0W 85 KT 100 MPH 48H 23/1200Z 13.6N 133.7W 90 KT 105 MPH 60H 24/0000Z 14.9N 136.5W 85 KT 100 MPH 72H 24/1200Z 16.1N 139.4W 75 KT 85 MPH 96H 25/1200Z 18.0N 145.5W 65 KT 75 MPH 120H 26/1200Z 18.5N 151.5W 55 KT 65 MPH $$ Forecaster Berg

Tags: number discussion storm douglas

 

Tropical Depression Seven-E Forecast Discussion Number 5

2020-07-21 10:39:13| Tropical Depression LIDIA

Issued at 200 AM PDT Tue Jul 21 2020

Tags: number discussion tropical depression

 
 

Tropical Storm Douglas Forecast Discussion Number 4

2020-07-21 10:35:45| National Hurricane Center (East Pacific)

Issued at 1100 PM HST Mon Jul 20 2020 000 WTPZ43 KNHC 210835 TCDEP3 Tropical Storm Douglas Discussion Number 4 NWS National Hurricane Center Miami FL EP082020 1100 PM HST Mon Jul 20 2020 Conventional and scatterometer satellite data indicate that Douglas has continued to strengthen, although cloud tops have recently begun to warm. A well-defined CDO, along with a curved convective band in the western semicircle, has developed, and an earlier SSMI/S overpass suggested that a primitive eye feature may be developing. The initial intensity of 50 kt is based on a 0506Z ASCAT-A pass that showed a small area of winds to 45 kt located less than 15 nmi northeast of the center. This intensity is supported by a consensus T3.0/45-kt estimate from TAFB and SAB, and an upward-trending UW-CIMSS ADT intensity estimate of T3.2/49 kt. The symmetrical 34-kt wind radii are based on the aforementioned ASCAT data. The initial motion estimate remains west-southwestward or 255/12 kt. A ridge located between TD-07E to the north and Douglas to the south is expected to keep the latter cyclone moving west-southwestward into Tuesday morning. After that time, the global and regional models are forecasting the ridge to weaken and retreat eastward faster than originally expected, resulting in Douglas turning west-northwestward in 36-48 h. As a result of this more poleward motion, the new NHC official track forecast was shifted north of the previous advisory track, but not as far north as the some of the consensus models and the ECMWF model, which is the northernmost track in the NHC model guidance suite. Although Douglas should remain in a favorable low-shear-high-SST environment for the next 72 h, which would typically favor rapid intensification, the small cyclone will be battling occasional intrusions of dry mid-level air. Such an intrusion appears to be occurring now based on the recent cloud-top warming that has been observed. Thus, only gradual strengthening, with brief periods of arrested development, is expected for the next 3 days. On days 4 and 5, the cyclone will be moving over 25-deg-C SSTs and into an even drier airmass, a negative combination that is expected to induce a slow weakening trend. The new official intensity forecast is similar to the previous advisory, and lies between the consensus models IVCN and NOAA-HCCA. FORECAST POSITIONS AND MAX WINDS INIT 21/0900Z 13.0N 122.8W 50 KT 60 MPH 12H 21/1800Z 12.5N 124.5W 55 KT 65 MPH 24H 22/0600Z 12.2N 127.0W 65 KT 75 MPH 36H 22/1800Z 12.3N 129.7W 75 KT 85 MPH 48H 23/0600Z 13.0N 132.2W 80 KT 90 MPH 60H 23/1800Z 14.2N 134.9W 80 KT 90 MPH 72H 24/0600Z 15.4N 137.6W 75 KT 85 MPH 96H 25/0600Z 17.0N 143.2W 65 KT 75 MPH 120H 26/0600Z 17.8N 148.9W 50 KT 60 MPH $$ Forecaster Stewart

Tags: number discussion storm douglas

 

Tropical Storm Douglas Forecast Discussion Number 3

2020-07-21 04:35:06| National Hurricane Center (East Pacific)

Issued at 500 PM HST Mon Jul 20 2020 745 WTPZ43 KNHC 210235 TCDEP3 Tropical Storm Douglas Discussion Number 3 NWS National Hurricane Center Miami FL EP082020 500 PM HST Mon Jul 20 2020 Satellite data indicate that the cyclone is strengthening. The system now has a small but well organized central dense overcast with curved bands on the west side of the circulation. All of the satellite intensity estimates are of tropical storm strength, and based on that data the initial intensity is raised to 35 kt, making the system Tropical Storm Douglas. The tropical storm is moving west-southwestward at 9 kt. A mid-level ridge situated to the north of Douglas off the northern Baja California coast should cause the storm to gradually turn westward during the next couple of days and then west-northwestward beyond that time. The models are in good agreement on this scenario, and only small changes were made to the previous prediction. Douglas is expected to be in quite favorable conditions of low vertical wind shear, high amounts of moisture, and warm SSTs during the next few days. Given these conducive environmental conditions and the storm's improved and compact structure, steady or possibly even rapid strengthening is possible during that time period. After a few days, however, a combination of higher shear, slightly cooler waters, and drier air should end the strengthening trend and induce weakening. The NHC intensity forecast lies near the higher end of the guidance. This forecast shows a faster rate of strengthening in the short term and more weakening at the end of the period compared to the previous forecast. FORECAST POSITIONS AND MAX WINDS INIT 21/0300Z 13.1N 121.6W 35 KT 40 MPH 12H 21/1200Z 12.5N 123.2W 45 KT 50 MPH 24H 22/0000Z 12.0N 125.6W 50 KT 60 MPH 36H 22/1200Z 11.9N 128.2W 60 KT 70 MPH 48H 23/0000Z 12.3N 130.8W 70 KT 80 MPH 60H 23/1200Z 13.2N 133.3W 75 KT 85 MPH 72H 24/0000Z 14.2N 136.1W 75 KT 85 MPH 96H 25/0000Z 15.9N 141.5W 60 KT 70 MPH 120H 26/0000Z 16.6N 147.0W 45 KT 50 MPH $$ Forecaster Cangialosi

Tags: number discussion storm douglas

 

Tropical Depression Seven-E Forecast Discussion Number 4

2020-07-21 04:33:08| Tropical Depression LIDIA

Issued at 500 PM HST Mon Jul 20 2020

Tags: number discussion tropical depression

 

Sites : [268] [269] [270] [271] [272] [273] [274] [275] [276] [277] [278] [279] [280] [281] [282] [283] [284] [285] [286] [287] next »