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Tropical Depression Three Forecast Discussion Number 3

2019-07-23 10:36:50| National Hurricane Center (Atlantic)

Issued at 500 AM EDT Tue Jul 23 2019 000 WTNT43 KNHC 230836 TCDAT3 Tropical Depression Three Discussion Number 3 NWS National Hurricane Center Miami FL AL032019 500 AM EDT Tue Jul 23 2019 Although deep convection has redeveloped near and to the northeast of the low-level center, the overall convective appearance is somewhat ragged. However, curved rain bands have been evident in Doppler radar data from Miami and Melbourne since around 0300 UTC, and Doppler velocity values of 35-40 kt have been detected in those bands between 15,000-20,000 ft. In addition, three ships located about 50 nmi northeast and east of the center have reported 28-29 kt wind speeds. Although those wind reports were elevated at 30-60 meters above the surface, they were reported outside of the rain bands. Based on this wind speed and radar information, the initial intensity has been increased to 30 kt. An Air Force Reserve reconnaissance aircraft will investigate the depression later this morning to provide a better estimate of the cyclone's intensity. The depression is now moving northward or 360/10 kt. There is essentially no change to the previous track or reasoning. The 06Z track model guidance continues to indicate that the cyclone will continue to move around western periphery of the sprawling Bermuda-Azores high pressure ridge. A northward motion is expected through today, followed by a turn toward the north-northeast with an increase in forward speed tonight. A northeastward motion is forecast on Wednesday, which will keep the center and strongest winds away from the coast of the southeastern United States. The new NHC track forecast is similar to the previous advisory and lies close to the various consensus models. Although significant strengthening of the depression is not expected, it is certainly possible that the cyclone could briefly reach tropical storm status in the 12-to-24-hour period when the system will be accelerating and the vertical wind shear decreases to less than 5 kt. However, in the event that the cyclone should become a tropical storm, the rapid northeastward motion will act to keep the strongest winds to the east of the center, well offshore of the U.S. coastal areas. By Wednesday afternoon, the combination of strong southwesterly vertical wind shear and interaction with an approaching cold front is expected to result in rapid weakening and dissipation of the cyclone. The official intensity forecast is similar to the previous advisory and shows dissipation by 36 hours. Direct impacts from the depression are expected to be limited to 1 to 3 inches of rainfall across the Bahamas today. FORECAST POSITIONS AND MAX WINDS INIT 23/0900Z 27.0N 79.5W 30 KT 35 MPH 12H 23/1800Z 29.6N 79.4W 30 KT 35 MPH 24H 24/0600Z 34.0N 76.5W 30 KT 35 MPH 36H 24/1800Z...DISSIPATED $$ Forecaster Stewart

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Tropical Depression Five-E Forecast Discussion Number 4

2019-07-23 04:36:46| National Hurricane Center (East Pacific)

Issued at 800 PM PDT Mon Jul 22 2019 000 WTPZ45 KNHC 230236 TCDEP5 Tropical Depression Five-E Discussion Number 4 NWS National Hurricane Center Miami FL EP052019 800 PM PDT Mon Jul 22 2019 This evening's visible satellite presentation consists of a rather ragged and shapeless cloud pattern with multiple cloud swirls seen rotating around the mean surface circulation center. The Dvorak satellite intensity estimates from both TAFB and SAB remain unchanged (T2.0/30 kt) as well as the initial intensity. There are no changes to the forecast intensity philosophy. Both the GFS and ECMWF SHIPS indicate that the northerly shear currently impinging on the northeastern portion of the system will persist through the forecast period. This inhibiting wind pattern along with cooler oceanic surface temperatures, ahead of the predicted track, should cause the cyclone to degenerate into a remnant low in 48 hours with dissipation in 4 days or less. The only model that shows strengthening to tropical storm status is the COAMPS-TC. For continuity purposes, I've elected to maintain this slight 12-24 hour intensification period in the official forecast. Because of the ill-defined circulation, the initial motion is estimated to be a bit uncertain north-northwestward, or 345/7 kt, within the low- to mid-level steering flow produced by high pressure located over the southwestern United States. The depression should continue moving in a general northwestward direction toward a break in the ridge to the northwest of the cyclone during the next 2 days. Afterward, as the system begins to weaken, a turn toward the west-northwest, within the tradewind flow, is anticipated. The model guidance is tightly clustered with the exception being the left outlier UKMET. The only adjustment in the NHC forecast is, again, a shift slightly to the left of the previous advisory, but follows both the TVCE and HCCA consensus models closely. FORECAST POSITIONS AND MAX WINDS INIT 23/0300Z 17.6N 116.8W 30 KT 35 MPH 12H 23/1200Z 18.5N 117.2W 35 KT 40 MPH 24H 24/0000Z 19.6N 117.9W 35 KT 40 MPH 36H 24/1200Z 20.5N 118.8W 30 KT 35 MPH 48H 25/0000Z 21.2N 119.8W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 26/0000Z 22.5N 122.3W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 27/0000Z...DISSIPATED $$ Forecaster Roberts

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Tropical Depression Three Forecast Discussion Number 2

2019-07-23 04:32:49| National Hurricane Center (Atlantic)

Issued at 1100 PM EDT Mon Jul 22 2019 000 WTNT43 KNHC 230232 TCDAT3 Tropical Depression Three Discussion Number 2 NWS National Hurricane Center Miami FL AL032019 1100 PM EDT Mon Jul 22 2019 The depression has become less organized this evening. Much of the deep convection seen earlier in the day has dissipated, and the cyclone currently consists of a swirl of low-level clouds with some shower activity. The initial intensity is held at 25 kt based on the earlier ASCAT data. The system is moving northwestward at 9 kt, steered by the southwestern periphery of the Atlantic subtropical ridge. A turn to the north and north-northeast with a notable increase in forward speed is expected on Tuesday as the depression moves in the flow between the subtropical ridge and an approaching deep-layer trough moving across the eastern United States. The NHC track forecast is similar to the previous one and keeps the center of the cyclone offshore of the east coast of Florida. This prediction is near the multi-model consensus TVCN. Significant strengthening of the depression is not expected given its poor initial state and because it is forecast to move into a region of strong southwesterly flow aloft by late Tuesday. In fact, the global and regional models all show the depression opening into a trough within the next 24 hours, with the remnants of the system becoming absorbed within a frontal zone off the southeast U.S. on Wednesday. The NHC intensity forecast is a little lower than the previous one and now shows dissipation occurring sooner, by 36 hours. Direct impacts from the depression are expected to be limited to 1 to 3 inches of rainfall in the Bahamas and along the east coast of Florida. FORECAST POSITIONS AND MAX WINDS INIT 23/0300Z 26.1N 79.3W 25 KT 30 MPH 12H 23/1200Z 28.4N 79.8W 25 KT 30 MPH 24H 24/0000Z 31.7N 78.5W 30 KT 35 MPH 36H 24/1200Z...DISSIPATED $$ Forecaster Cangialosi

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Tropical Depression Five-E Forecast Discussion Number 3

2019-07-22 22:37:10| National Hurricane Center (East Pacific)

Issued at 200 PM PDT Mon Jul 22 2019 000 WTPZ45 KNHC 222037 TCDEP5 Tropical Depression Five-E Discussion Number 3 NWS National Hurricane Center Miami FL EP052019 200 PM PDT Mon Jul 22 2019 The depression is struggling to become better organized. Visible satellite imagery shows multiple low-level swirls moving about a mean center of circulation, with the deep convection being confined to the southwestern semicircle due to northeasterly shear. Both subjective and objective satellite intensity estimates indicate that the system intensity remains 30 kt. Since the exact center is somewhat difficult to locate, the initial motion is a rather uncertain 345/08kt. There has been a slight westward shift in the majority of the track guidance, and this is possibly due to them steering a weaker system than previously forecast. The depression is expected to continue to move north-northwest for the next 24-36 hours between a weak mid-level trough to its west, and a building mid-level ridge to its northeast. After 36 hours, the system should make a gradual turn toward the west-northwest as the cyclone weakens and becomes carried by the low-level steering currents. There is a shrinking window of opportunity for the depression to get its act together before it moves over SSTs below 26 C and into a stable atmospheric environment in 24-36 hours. Additionally, the 15 to 20 kt of shear currently over the system may prevent it from intensifying any further. However, the official forecast calls for the depression to intensify slightly over marginal SSTs into a weak tropical storm tonight, followed by a weakening trend beginning in about 24 hours. The cyclone should weaken into a remnant low by 48 hours and then dissipate late this week. The intensity forecast through 24 hours remains the same as the previous advisory, but it has been lowered beyond 24 hours and is in agreement with the majority of the intensity guidance. FORECAST POSITIONS AND MAX WINDS INIT 22/2100Z 16.7N 116.6W 30 KT 35 MPH 12H 23/0600Z 17.8N 116.9W 35 KT 40 MPH 24H 23/1800Z 19.1N 117.4W 35 KT 40 MPH 36H 24/0600Z 20.2N 118.0W 30 KT 35 MPH 48H 24/1800Z 21.0N 119.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 25/1800Z 22.1N 121.3W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 26/1800Z...DISSIPATED $$ Forecaster Latto/Pasch

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Tropical Depression Three Forecast Discussion Number 1

2019-07-22 22:32:11| National Hurricane Center (Atlantic)

Issued at 500 PM EDT Mon Jul 22 2019 000 WTNT43 KNHC 222032 TCDAT3 Tropical Depression Three Discussion Number 1 NWS National Hurricane Center Miami FL AL032019 500 PM EDT Mon Jul 22 2019 Deep convection has increased in association with the small low pressure area we have been monitoring near the Bahamas. Animation of visible satellite images and scatterometer data indicate that a closed low-level circulation formed today, and therefore advisories are being initiated on the system. Conventional surface observations along with the scatterometer measurements indicate that the maximum sustained winds in the cyclone are near 25 kt. The system is in a marginally favorable environment for strengthening, as a special 1800 UTC sounding taken by the National Weather Service Forecast Office here in Miami showed a layer of dry air near the 700 mb level. The global models do not intensify the system, and only a slight increase in strength appears likely. In 36 to 48 hours, the models indicate that this system will be absorbed by a frontal trough near the U.S. east coast. The initial motion estimate is northwestward or 305/11 kt. Over the next day or so, the tropical cyclone should move around the western periphery of a mid-level subtropical ridge, with the center of the depression expected to remain offshore of the Florida east coast and the southeastern United States until dissipation. The official track forecast follows a small consensus of the only models that were able to follow the center of the depression in the predicted fields. FORECAST POSITIONS AND MAX WINDS INIT 22/2100Z 25.6N 78.6W 25 KT 30 MPH 12H 23/0600Z 27.2N 79.7W 30 KT 35 MPH 24H 23/1800Z 30.1N 79.6W 30 KT 35 MPH 36H 24/0600Z 33.7N 77.8W 25 KT 30 MPH 48H 24/1800Z...DISSIPATED $$ Forecaster Pasch

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