Home › discussion
 

Keywords :   


Tag: discussion

Hurricane ANDRES Forecast Discussion Number 8

2015-05-30 04:44:08| National Hurricane Center (East Pacific)

Issued at 800 PM PDT FRI MAY 29 2015 000 WTPZ41 KNHC 300244 TCDEP1 HURRICANE ANDRES DISCUSSION NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL EP012015 800 PM PDT FRI MAY 29 2015 Andres is gradually intensifying. The cyclone is maintaining a symmetric central dense overcast, consisting of plenty of cold-topped deep convection. A 2256 UTC GPM microwave pass showed numerous, well organized convective bands and a closed low-level ring of convection; in addition, a warm spot has recently become evident in infrared satellite imagery. Satellite intensity estimates at 0000 UTC were 4.0/65 kt and 4.5/75 kt from SAB and TAFB, respectively, and the latest ADT value from UW-CIMSS is 4.3/72 kt. Since that time, Andres' cloud pattern has increased further in organization, and the initial intensity is raised to 75 kt. Andres' motion has shifted toward the right or northwest, 320/06, in response to a weakness in the subtropical ridge along 115w caused by a shortwave trough near the Baja California peninsula. After this feature moves eastward tomorrow, the ridge is forecast to rebuild which should result in the track's bending toward the west- northwest and west by 36 to 48 hours. For this forecast cycle, there has been a notable shift in the guidance to the left through 48 hours, and the track has generally been shifted in that direction but not as far left as the ECMWF and GFS solutions. After 48 hours, the spread in the guidance increases, with the GFS depicting a stronger cyclone on the northern end of the guidance envelope and the ECMWF a weaker one on the southern edge. The official NHC forecast track lies nearly between the two extremes, close to the multi-model consensus (TVCE). The intensity forecast is challenging. Despite moderate northerly shear, the cyclone has slowly strengthened during the past 24 hours. Although this shear is forecast to persist through tomorrow, the cyclone's inner-core structure suggests that further intensification should occur. The official forecast exceeds the statistical-dynamical guidance through 36 hours on the basis of current trends and the hurricane's well organized inner core. Although the shear should lessen in a day or two, weakening should commence as thermodynamics in the near-storm environment gradually become less conducive for intensification. The official NHC intensity forecast shows steady weakening after 36 hours, very similar to the multi-model consensus (ICON). FORECAST POSITIONS AND MAX WINDS INIT 30/0300Z 13.4N 115.2W 75 KT 85 MPH 12H 30/1200Z 14.2N 116.0W 85 KT 100 MPH 24H 31/0000Z 15.1N 117.1W 85 KT 100 MPH 36H 31/1200Z 15.7N 118.4W 80 KT 90 MPH 48H 01/0000Z 16.2N 119.6W 75 KT 85 MPH 72H 02/0000Z 17.4N 122.3W 60 KT 70 MPH 96H 03/0000Z 18.6N 125.7W 50 KT 60 MPH 120H 04/0000Z 19.1N 128.8W 35 KT 40 MPH $$ Forecaster Kimberlain

Tags: number discussion forecast hurricane

 

Hurricane ANDRES Forecast Discussion Number 7

2015-05-29 22:56:34| National Hurricane Center (East Pacific)

Issued at 300 PM MDT FRI MAY 29 2015 000 WTPZ41 KNHC 292056 TCDEP1 HURRICANE ANDRES DISCUSSION NUMBER 7...CORRECTED NWS NATIONAL HURRICANE CENTER MIAMI FL EP012015 300 PM MDT FRI MAY 29 2015 Corrected to change NHC model to NHC model guidance Convective banding features have increased since the previous advisory, and a tight banding eye feature has occasionally appeared in visible satellite imagery. Dvorak satellite estimates are a consensus T4.0/65 kt from TAFB and SAB, and UW-CIMSS ADT values are T4.3/72 kt. Based on these data, Andres has been upgraded to a 65-kt hurricane. Andres has made the anticipated turn toward the northwest, and the initial motion estimate is now 310/06 kt. This general motion is expected to continue for about the next 36-48 hours as the hurricane moves around the western periphery of a deep-layer ridge located across mainland Mexico and Baja California. The ridge is forecast to gradually build westward after 72 hours, forcing Andres to turn back toward the west-northwest. The NHC model guidance is in excellent agreement on this developing scenario, and the guidance is tightly clustered around the previous forecast track. As a result, the official forecast track is just an update and extension of the previous advisory track. Despite moderate northerly vertical wind shear, Andres has maintained a fairly impressive outflow pattern. However, the 850-200 mb vertical wind shear is forecast by the SHIPS model to increase to around 15 kt during the next 24 hours, followed by decreasing shear at 36 to 48 hours. Now that Andres has established better inner-core convection and a possible eye feature, at least modest strengthening should occur during the next 48 hours or so. Thereafter, decreasing sea surface temperatures and cooler and more stable low-level air lying just to the northwest of the hurricane should begin to affect Andres. Visible satellite imagery already indicates that cold air stratocumulus clouds are being advected into the northwestern portion of the outer circulation, which should mitigate the otherwise favorable thermodynamic conditions. As a result, a steady decrease in the intensity should occur after 72 hours, despite the low vertical wind shear regime through which the cyclone will be moving. The NHC intensity forecast is similar to the previous advisory, and is above the intensity consensus model ICON and close to the SHIPS model. FORECAST POSITIONS AND MAX WINDS INIT 29/2100Z 12.8N 114.8W 65 KT 75 MPH 12H 30/0600Z 13.6N 115.6W 70 KT 80 MPH 24H 30/1800Z 14.7N 116.6W 75 KT 85 MPH 36H 31/0600Z 15.7N 117.7W 80 KT 90 MPH 48H 31/1800Z 16.4N 119.1W 80 KT 90 MPH 72H 01/1800Z 17.4N 121.9W 65 KT 75 MPH 96H 02/1800Z 18.5N 125.4W 50 KT 60 MPH 120H 03/1800Z 18.8N 128.7W 40 KT 45 MPH $$ Forecaster Stewart

Tags: number discussion forecast hurricane

 
 

Tropical Storm ANDRES Forecast Discussion Number 6

2015-05-29 16:49:36| National Hurricane Center (East Pacific)

Issued at 900 AM MDT FRI MAY 29 2015 000 WTPZ41 KNHC 291449 TCDEP1 TROPICAL STORM ANDRES DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP012015 900 AM MDT FRI MAY 29 2015 Andres is just below hurricane strength. Although an eye feature is no longer apparent in infrared and visible satellite images, the associated convection has been deepening during the past few hours. Microwave images show that the structure of Andres is asymmetric with well-defined banding to the south of the center and limited more fragmented bands to the north of the center. A blend of the latest Dvorak estimates and ADT values still yield an intensity estimate of 60 kt. The SHIPS model indicates that Andres is currently experiencing about 15 kt of northerly shear, which is likely part of the reason why the storm has leveled off in intensity for the time being. This shear is expected to persist for another 12 to 24 hours, but it should lessen some thereafter. Therefore, slow strengthening is expected during the next couple of days while the cyclone remains over warm water. Beyond a couple of days, Andres is expected to move over cooler water and into a drier and more stable airmass. These unfavorable thermodynamic conditions should cause the system to weaken. The official intensity forecast is a little lower than the previous one, and lies at the high end of the model guidance. Andres continues on a west-northwestward track at about 8 kt. A weakness in the subtropical ridge should cause the storm to move northwestward during the next day or two. After that time, a turn back to the west-northwest is predicted when the ridge restrengthens to the north of the storm. The model guidance is in good agreement overall, and the official forecast is similar to the previous one and lies close to the consensus aids. FORECAST POSITIONS AND MAX WINDS INIT 29/1500Z 12.5N 114.6W 60 KT 70 MPH 12H 30/0000Z 13.3N 115.5W 65 KT 75 MPH 24H 30/1200Z 14.3N 116.4W 70 KT 80 MPH 36H 31/0000Z 15.4N 117.4W 75 KT 85 MPH 48H 31/1200Z 16.2N 118.5W 80 KT 90 MPH 72H 01/1200Z 17.3N 121.3W 65 KT 75 MPH 96H 02/1200Z 18.2N 124.3W 50 KT 60 MPH 120H 03/1200Z 18.8N 127.4W 40 KT 45 MPH $$ Forecaster Cangialosi

Tags: number discussion storm tropical

 

Tropical Storm ANDRES Forecast Discussion Number 5

2015-05-29 10:41:33| National Hurricane Center (East Pacific)

Issued at 300 AM MDT FRI MAY 29 2015 000 WTPZ41 KNHC 290841 TCDEP1 TROPICAL STORM ANDRES DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL EP012015 300 AM MDT FRI MAY 29 2015 Andres's intensification trend appears to have ceased for the moment. Infrared satellite imagery suggests that the cyclone is trying to develop a banded-eye structure, but the overall pattern really hasn't improved much since the last advisory. In fact, the Dvorak final-T number from TAFB decreased to 3.5, and remained at 3.5 from SAB, so the initial intensity is being held at 60 kt. The storm is moving a little slower to the west-northwest, or 295/8 kt, to the south of the subtropical ridge. A slight weakness in the ridge should allow Andres to move northwestward later today through Saturday night. The ridge is forecast to rebuild, however, and the cyclone will likely move west-northwestward and then westward on days 3-5. There has been no apparent shift in the latest track guidance as there had been in previous cycles, and therefore the updated NHC track forecast is essentially unchanged from the previous one. The SHIPS model diagnostics indicate that a modest amount of north- northeasterly shear is affecting Andres, which could be the reason for the temporary hiatus in strengthening. SHIPS indicates that the current level of shear should continue for the next 24 hours, and after that the thermodynamic environment becomes gradually less favorable for significant strengthening. Due to these less-than- ideal conditions, the latest intensity guidance shows Andres peaking at a lower intensity compared to previous cycles, and the updated NHC intensity forecast has therefore been lowered a bit. Even with this adjustment, however, the official forecast is still higher than most of the models, especially at 48 hours. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 12.0N 113.9W 60 KT 70 MPH 12H 29/1800Z 12.8N 114.8W 70 KT 80 MPH 24H 30/0600Z 13.8N 115.7W 75 KT 85 MPH 36H 30/1800Z 14.8N 116.6W 80 KT 90 MPH 48H 31/0600Z 15.7N 117.5W 85 KT 100 MPH 72H 01/0600Z 17.0N 120.0W 70 KT 80 MPH 96H 02/0600Z 18.0N 123.0W 55 KT 65 MPH 120H 03/0600Z 18.5N 126.0W 40 KT 45 MPH $$ Forecaster Berg

Tags: number discussion storm tropical

 

Tropical Storm ANDRES Forecast Discussion Number 4

2015-05-29 04:34:33| National Hurricane Center (East Pacific)

Issued at 900 PM MDT THU MAY 28 2015 000 WTPZ41 KNHC 290234 TCDEP1 TROPICAL STORM ANDRES DISCUSSION NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL EP012015 900 PM MDT THU MAY 28 2015 Andres is continuing to intensify. Although the cloud tops near the center have recently warmed, the latest microwave and conventional satellite images are now showing the formation of a ragged eye. An average of the latest intensity estimates is just below hurricane strength, so the initial wind speed is set to 60 kt. The storm appears to be moving to the west-northwest at about 9 kt, a bit slower than before. Andres should turn northwestward tomorrow as a result of a slight weakness in the subtropical ridge. In a few days, the ridge restrengthens, which should then steer Andres more toward the west-northwest and west. The latest models have again shifted to the left, apparently due to a stronger ridge than originally predicted, and the official forecast follows the westward trend in the model consensus. Although it seems clear that the cyclone should strengthen over the next couple of days with generally favorable environmental conditions, the amount of shear is a wild card for this forecast. Most of the global models are showing shear values that are higher than ideal for rapid intensification, and the shear is the biggest inhibitor in the latest SHIPS RI index. Andres has been moving left of expected, however, which has been prolonging the lower shear and warmest water conditions. Thus, the new NHC wind speed forecast will remain above most of the guidance, similar to the previous prediction, and it would not be surprising if this forecast is too low for the reasons given above. After 48 hours, Andres should begin to weaken when it encounters cooler waters and a more stable air mass. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 11.8N 113.3W 60 KT 70 MPH 12H 29/1200Z 12.5N 114.4W 70 KT 80 MPH 24H 30/0000Z 13.5N 115.4W 80 KT 90 MPH 36H 30/1200Z 14.4N 116.2W 85 KT 100 MPH 48H 31/0000Z 15.3N 116.9W 90 KT 105 MPH 72H 01/0000Z 16.7N 118.9W 80 KT 90 MPH 96H 02/0000Z 17.5N 121.5W 60 KT 70 MPH 120H 03/0000Z 18.0N 124.5W 45 KT 50 MPH $$ Forecaster Blake

Tags: number discussion storm tropical

 

Sites : [1029] [1030] [1031] [1032] [1033] [1034] [1035] [1036] [1037] [1038] [1039] [1040] [1041] [1042] [1043] [1044] [1045] [1046] [1047] [1048] next »