Home › discussion
 

Keywords :   


Tag: discussion

PUB Discussion Guide for Hydro 8.23.2017

2017-09-21 01:45:23| PortlandOnline

PDF Document, 49kbCategory: August 24, 2017 Materials

Tags: guide discussion pub hydro

 

Hurricane Maria Forecast Discussion Number 19

2017-09-20 22:39:25| National Hurricane Center (Atlantic)

Issued at 500 PM AST Wed Sep 20 2017 000 WTNT45 KNHC 202039 TCDAT5 Hurricane Maria Discussion Number 19 NWS National Hurricane Center Miami FL AL152017 500 PM AST Wed Sep 20 2017 An Air Force Reserve reconnaissance aircraft found that Maria's center moved off the northwestern coast of Puerto Rico just before 1800 UTC, but the hurricane appears to have taken quite a hit from the high mountains of the island. The aircraft measured a maximum flight-level wind of 106 kt to the east of the center and SFMR surface winds as high as 91 kt. The initial intensity is therefore set to 95 kt. The central pressure has also risen considerably, and the latest report from the airplane is 957 mb. Maria may have taken a temporary jog west-northwestward across Puerto Rico, likely due to topographic effects, but the longer-term motion remains northwestward, or 305/10 kt. Maria should maintain a northwestward motion for the next 36 hours while it remains on the southwestern periphery of a mid-level high over the western Atlantic. After 36 hours, Maria is expected to turn northward between the high and a broad trough extending from Tropical Storm Jose southwestward into the Gulf of Mexico. The updated track guidance remains in excellent agreement on this scenario, and the overall guidance envelope has shifted a bit eastward on this cycle. The new NHC forecast is therefore nudged a little east of the previous forecast toward the various consensus aids. It may take some time for Maria's structure to reorganize itself now that it is back over water. Although the intensity models are not all that enthusiastic about strengthening, the environment looks conducive for intensification, and the NHC forecast lies at the upper bound of the guidance, closest to the HWRF solution. It would not be surprising, however, if Maria eventually strengthens more than shown here. Some weakening is expected by days 4 and 5 due to increased shear, as well as Maria possibly moving over the cold wake of Tropical Storm Jose to the east of the Carolinas. We would like to thank the crew of the latest Air Force Reserve mission for their incredible service today. After beginning their mission this morning before the center first moved onshore, the crew went above and beyond, returning to Curacao to refuel, and then heading back to Puerto Rico to catch Maria's center when it first moved back off the coast. The data collected by the crew was incredibly important for us to analyze Maria's intensity and structure after moving across the island, and we are grateful for their effort. KEY MESSAGES: 1. Maria's core is moving away from the northwestern coast of Puerto Rico, and strong winds and storm surge flooding should subside through early Thursday. However, heavy rainfall is expected to continue, and catastrophic flash flooding is occurring on the island, especially in areas of mountainous terrain. Everyone in Puerto Rico should continue to follow advice from local officials to avoid these life-threatening flooding conditions. 2. A Hurricane Warning is in effect for the northern coast of the Dominican Republic, the Turks and Caicos Islands, and the southeastern Bahamas, where Maria is expected to bring dangerous wind, storm surge, and heavy rainfall. FORECAST POSITIONS AND MAX WINDS INIT 20/2100Z 18.8N 67.3W 95 KT 110 MPH 12H 21/0600Z 19.5N 68.2W 95 KT 110 MPH 24H 21/1800Z 20.5N 69.3W 100 KT 115 MPH 36H 22/0600Z 21.6N 70.3W 105 KT 120 MPH 48H 22/1800Z 22.9N 71.1W 105 KT 120 MPH 72H 23/1800Z 25.8N 72.2W 100 KT 115 MPH 96H 24/1800Z 29.0N 72.5W 90 KT 105 MPH 120H 25/1800Z 31.5N 72.0W 80 KT 90 MPH $$ Forecaster Berg

Tags: number discussion maria forecast

 
 

Tropical Storm Jose Forecast Discussion Number 62

2017-09-20 22:39:03| National Hurricane Center (Atlantic)

Issued at 500 PM AST Wed Sep 20 2017 000 WTNT42 KNHC 202038 TCDAT2 Tropical Storm Jose Discussion Number 62 NWS National Hurricane Center Miami FL AL122017 500 PM AST Wed Sep 20 2017 Jose has generally changed little since the previous advisory. Geostationary and microwave satellite data show that the storm is still producing well-defined convective bands on the north side of the circulation. Some of these outer bands are approaching the southern New England coastline. The initial wind speed is held at 60 kt based on the earlier aircraft data. This estimate is also in fair agreement with an ASCAT pass from earlier today, which also showed that Jose has a very large wind field. Another Air Force reconnaissance aircraft is scheduled to investigate this system later this evening, and should provide a better assessment of Jose's intensity. The tropical storm is moving northeastward at 7 kt steered by a trough over eastern Canada. This trough should cause Jose to move east-northeastward at a slower pace tonight. Thereafter, the trough is expected to bypass the storm, leaving Jose in very weak steering currents. As a result, Jose is forecast to drift westward beginning Thursday night and continue in that direction through the weekend. The models have trended a little to the west at the end of the forecast period, and the NHC track forecast has followed suit. Jose is currently moving along the edge of the Gulf Stream, and is expected to remain over this oceanic environment for a few more days. These relatively cool waters, a progressively drier airmass, and an expected increase in wind shear should cause a gradual weakening trend during the next several days. The models are in good agreement on this scenario, and the NHC intensity forecast is largely an update of the previous one. KEY MESSAGES: 1. While the center of Jose is forecast to remain offshore of the U.S. east coast, the large cyclone is expected to cause some direct impacts in portions of New England during the next day or two, and a tropical storm warning remains in effect for Cape Cod, Block Island, Martha's Vineyard, and Nantucket. 2. Minor to moderate coastal flooding is possible from Delaware to southern New England during the next several days. Please see products issued by local National Weather Service forecast offices. 3. Swells generated by Jose are affecting Bermuda and much of the U.S. east coast and will likely cause dangerous surf and rip current conditions for the next several days in these areas. 4. Jose is expected to produce additional rainfall accumulations of 1 to 2 inches over Martha's Vineyard and Cape Cod, and 2 to 4 inches in Nantucket as it passes offshore. This rainfall could cause isolated flash flooding. FORECAST POSITIONS AND MAX WINDS INIT 20/2100Z 39.2N 69.1W 60 KT 70 MPH 12H 21/0600Z 39.6N 68.1W 55 KT 65 MPH 24H 21/1800Z 39.6N 67.9W 50 KT 60 MPH 36H 22/0600Z 39.6N 68.3W 45 KT 50 MPH 48H 22/1800Z 39.5N 69.2W 40 KT 45 MPH...POST-TROPICAL 72H 23/1800Z 39.3N 70.0W 35 KT 40 MPH...POST-TROPICAL 96H 24/1800Z 39.3N 70.3W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 25/1800Z 39.4N 71.2W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Cangialosi

Tags: number discussion jose storm

 

Hurricane Maria Forecast Discussion Number 18

2017-09-20 16:40:55| National Hurricane Center (Atlantic)

Issued at 1100 AM AST Wed Sep 20 2017 000 WTNT45 KNHC 201440 TCDAT5 Hurricane Maria Discussion Number 18 NWS National Hurricane Center Miami FL AL152017 1100 AM AST Wed Sep 20 2017 The last radar image from the San Juan WSR-88D was received at 0950 UTC when Maria's eye was located only about 5 n mi off the southeastern coast of Puerto Rico. Subsequent 1-minute imagery from the GOES-16 satellite, as well as surface observations, indicate that the eye made landfall a little south of Yabucoa Harbor, Puerto Rico, around 1015 UTC. Now that the center is moving over the mountainous terrain of the island, the eye has become cloud filled, and the infrared satellite presentation has degraded. Without radar velocity data, the initial intensity is incredibly uncertain, but my best guess is 120 kt based on a typical inland decay rate. Maria's center is expected to move off the northern coast of Puerto Rico soon, and an Air Force Reserve reconnaissance aircraft is scheduled to intercept the center early this afternoon and provide a better estimate of how much Maria has weakened. The initial motion is northwestward, or 305/10 kt. This northwestward motion is forecast to continue for the next 48 hours, followed by a turn toward the north by days 4 and 5, while Maria moves between a mid-level high centered southeast of Bermuda and a broad trough extending from Tropical Storm Jose southwestward into the Gulf of Mexico. The track guidance is tightly clustered this cycle, and there were no significant changes made to the NHC forecast track. Once Maria moves off the coast of Puerto Rico, it will take some time for the structure to reorganize over the warm waters of the Atlantic Ocean. However, the shear is expected to be less than 10 kt for the next 24-36 hours, and Maria has an opportunity to restrengthen a bit over that time period. After 36 hours, a gradual increase in shear is likely to lead to a commensurate gradual decrease in the hurricane's intensity through the end of the forecast period. Since the SHIPS model, in particular, responds to the favorable conditions for intensification, the NHC intensity forecast lies just above the intensity consensus through much of the forecast period. Since we don't have radar imagery from San Juan, and the eye has become cloud filled in satellite imagery, the hourly position updates are being discontinued. KEY MESSAGES: 1. Maria's core is moving over Puerto Rico, with life-threatening wind, storm surge, and rainfall impacts continuing over the island. Everyone in Puerto Rico should follow advice from local officials to avoid life-threatening flooding from storm surge and rainfall. A Hurricane Warning remains in effect for the Virgin Islands, but conditions should gradually improve there later today. 2. Wind speeds atop and on the windward sides of hills and mountains and on high-rise buildings could be much stronger than the near-surface winds indicated in this advisory. 3. A Hurricane Warning is also in effect for the northern coast of the Dominican Republic, the Turks and Caicos Islands and the southeastern Bahamas, where Maria is expected to bring dangerous wind, storm surge, and heavy rainfall. FORECAST POSITIONS AND MAX WINDS INIT 20/1500Z 18.4N 66.5W 120 KT 140 MPH...OVER PUERTO RICO 12H 21/0000Z 19.2N 67.6W 120 KT 140 MPH 24H 21/1200Z 20.2N 69.0W 125 KT 145 MPH 36H 22/0000Z 21.2N 70.1W 125 KT 145 MPH 48H 22/1200Z 22.4N 71.0W 120 KT 140 MPH 72H 23/1200Z 25.3N 72.4W 110 KT 125 MPH 96H 24/1200Z 28.5N 73.0W 100 KT 115 MPH 120H 25/1200Z 31.5N 73.0W 90 KT 105 MPH $$ Forecaster Berg

Tags: number discussion maria forecast

 

Tropical Storm Jose Forecast Discussion Number 61

2017-09-20 16:34:53| National Hurricane Center (Atlantic)

Issued at 1100 AM EDT Wed Sep 20 2017 000 WTNT42 KNHC 201434 TCDAT2 Tropical Storm Jose Discussion Number 61 NWS National Hurricane Center Miami FL AL122017 1100 AM EDT Wed Sep 20 2017 The Air Force Hurricane Hunters have been investigating Jose this morning and found maximum flight-level winds of 78 kt at 5,000 feet and peak SFMR surface winds of 56 kt. Based on these data, the initial wind speed is set at 60 kt, which is slightly higher than the previous estimate. Jose remains a sprawling cyclone, with tropical storm force winds extending 180 n mi from the center. Although Jose does not have a purely tropical appearance, it still has a warm core and well-defined convective bands, especially to the north of the center. Jose is moving northeastward at 7 kt toward a mid- to upper-level trough over eastern Canada. A slightly slower northeastward to east-northeastward motion is expected through tonight. Thereafter, the trough is expected to lift out, allowing a mid-level high pressure system to build to the northwest of Jose. This will likely cause the storm to reverse its course and drift westward or west-southwestward. In about 3 days, however, the models suggest that Jose will be caught in very weak steering currents, and the NHC official track forecast now shows Jose stationary from 72 to 120 hours. The tropical storm is moving over a tight SST gradient associated with the north wall of the Gulf Stream current, and it will likely remain over this gradient for the next several days. These relatively cool SSTs and dry air should cause a slow weakening trend, and a gradual transition to a post-tropical cyclone. The NHC intensity forecast is not too different from the previous one and is in best agreement with the consensus models. KEY MESSAGES: 1. While the center of Jose is forecast to remain offshore of the U.S. east coast, the large cyclone is expected to cause some direct impacts in portions of New England during the next couple of days, and a tropical storm warning is in effect for Cape Cod, Block Island, Martha's Vineyard, and Nantucket. 2. Minor to moderate coastal flooding is possible from Delaware to southern New England during the next several days. Please see products issued by local National Weather Service forecast offices. 3. Swells generated by Jose are affecting Bermuda and much of the U.S. east coast and will likely cause dangerous surf and rip current conditions for the next several days in these areas. 4. Jose is expected to produce additional rainfall accumulations of 1 to 2 inches over Martha's Vineyard and Cape Cod, and 2 to 4 inches in Nantucket as it passes offshore today into Thursday. This rainfall could cause isolated flash flooding. FORECAST POSITIONS AND MAX WINDS INIT 20/1500Z 39.0N 70.0W 60 KT 70 MPH 12H 21/0000Z 39.5N 69.0W 60 KT 70 MPH 24H 21/1200Z 39.8N 68.1W 55 KT 65 MPH 36H 22/0000Z 39.6N 68.3W 45 KT 50 MPH 48H 22/1200Z 39.5N 69.0W 40 KT 45 MPH...POST-TROPICAL 72H 23/1200Z 39.3N 70.0W 40 KT 45 MPH...POST-TROPICAL 96H 24/1200Z 39.3N 70.0W 35 KT 40 MPH...POST-TROPICAL 120H 25/1200Z 39.3N 70.0W 30 KT 35 MPH...POST-TROPICAL $$ Forecaster Cangialosi

Tags: number discussion jose storm

 

Sites : [656] [657] [658] [659] [660] [661] [662] [663] [664] [665] [666] [667] [668] [669] [670] [671] [672] [673] [674] [675] next »