Tropical Storm Juliette

Hurricane Juliette Track 2300 Hours September 5 2019
Hurricane Juliette Track 2300 Hours September 5 2019

Hurricane Juliette Satellite 0300 Hours September 3 2019

NWS National Hurricane Center Miami FL 1100 PM HST Thu Sep 05 2019

Tropical Storm Juliette (see video below) This evening’s satellite presentation is showing a considerable amount of deterioration of Juliette’s inner core. The eastern portion of the eyewall has eroded, cloud tops have continue to warm, and it appears as though some drier mid-level air is intruding from the northwest. Subjective satellite intensity estimates from TAFB and SAB, and the UW-CIMSS Objective T-number supports lowering the initial intensity to 70 kt.

Although the upper-level winds are expected to remain in a favorable pattern during the next couple days, the hurricane will be moving over decreasing sea surface temperatures and into increasingly stable thermodynamic conditions. Subsequently, gradual weakening should continue through the entire forecast period, and Juliette is expected to become a remnant low in 3 days, or less. The intensity forecast is basically a compromise of the NOAA HFIP HCCA and the global models beyond the 48-hour period.

The initial motion continues to be northwestward, or 305/9 kt. A mid-level ridge extending from the southwestern United States over the eastern Pacific should induce a west-northwestward turn on Friday, and this general motion should continue through the next couple of days. Toward the end of the period, a westward motion should commence as Juliette degenerates into a vertically shallow depression, and eventually, a remnant low, and becomes steered by the low-level trade wind flow. The track forecast is an update of the previous advisory and sides with the TVCE model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  06/0900Z 22.4N 122.7W   70 KT  80 MPH - Category 1 (WSW Cabo San Lucas, Mexico)
 12H  06/1800Z 23.0N 124.2W   60 KT  70 MPH - Tropical Storm (WSW Cabo San Lucas, Mexico)
 24H  07/0600Z 23.6N 126.4W   50 KT  60 MPH - Tropical Storm (WSW Cabo San Lucas, Mexico)
 36H  07/1800Z 23.8N 128.5W   40 KT  45 MPH - Tropical Storm (WSW Cabo San Lucas, Mexico)
 48H  08/0600Z 23.8N 130.6W   35 KT  40 MPH - Tropical Depression (WSW Hilo, Hawaii)
 72H  09/0600Z 23.4N 135.0W   25 KT  30 MPH - Tropical Depression (WSW Hilo, Hawaii)
 96H  10/0600Z 23.4N 138.2W   25 KT  30 MPH - Tropical Depression (WSW Hilo, Hawaii)
120H  11/0600Z 23.8N 141.7W   20 KT  25 MPH - Tropical Depression (WSW Hilo, Hawaii)

NWS National Hurricane Center Miami FL 800 AM PDT Thu Sep 05 2019

There has been little overall change in Hurricane Juliette’s cloud pattern this morning. The hurricane still has a large, ragged eye, but the cloud tops within the surrounding ring of convection have warmed during the past couple of hours. Earlier microwave imagery showed a well-defined low-level eye that is located a little south of the satellite fixes from TAFB and SAB. The various satellite intensity estimates range from 77 to 85 kt, so the initial wind speed of 80 kt is maintained for this advisory.

Juliette will be moving over gradually lower sea surface temperatures and into a more stable air mass but the vertical shear is expected to remain fairly low during the next couple days. This will likely result in a somewhat slower rate of weakening than is typical for east Pacific hurricanes moving over cool SSTs. Later in the period, southwesterly shear is expected to increase which should cause the cyclone to degenerate into a remnant low in 3 to 4 days. The NHC intensity foreast is closest to the SHIPS intensity model.

The initial motion estimate is 305/8 kt. A general northwestward motion around the southwestern portion of the mid-level ridge over the southwestern United States should continue today. A turn toward the west-northwest, and then the west, is expected over the next couple of days as Juliette gradually weakens and is steered by the easterly low- to mid-level flow. The new NHC track forecast is near the middle of the guidance envelope but is a little faster than the previous advisory to be closer to the multi-model consensus aids.

FORECAST POSITIONS AND MAX WINDS

INIT  05/1500Z 20.6N 119.9W   80 KT  90 MPH - Category 1 (WSW Cabo San Lucas, Mexico)
 12H  06/0000Z 21.5N 121.3W   75 KT  85 MPH - Category 1 (WSW Cabo San Lucas, Mexico)
 24H  06/1200Z 22.6N 123.3W   65 KT  75 MPH - Category 1 (WSW Cabo San Lucas, Mexico)
 36H  07/0000Z 23.3N 125.4W   55 KT  65 MPH - Tropical Storm (WSW Cabo San Lucas, Mexico)
 48H  07/1200Z 23.6N 127.4W   45 KT  50 MPH - Tropical Storm (ENE Hilo, Hawaii)
 72H  08/1200Z 23.6N 131.2W   35 KT  40 MPH - Tropical Depression (ENE Hilo, Hawaii)
 96H  09/1200Z 23.2N 134.5W   30 KT  35 MPH - Tropical Depression (ENE Hilo, Hawaii)
120H  10/1200Z 23.0N 137.0W   25 KT  30 MPH - Tropical Depression (ENE Hilo, Hawaii)

NWS Central Pacific Hurricane Center Honolulu HI 800 AM PDT Wed Sep 04 2019

Juliette continues to look somewhat ragged in conventional infrared satellite imagery this morning. A warm spot, which appears to be an eye, has been showing up intermittently during the past several hours. A 0914Z AMSR microwave pass indicated the eyewall was open in the south quadrant, so all indications are that additional weakening has taken place. The latest subjective and objective T-numbers provided by the satellite fix agencies also suggest weakening.

Based on this input, the initial intensity is lowered to 85 kt for this advisory. The initial motion for this advisory is west-northwestward, or 295/5 kt. Juliette is being steered by the circulation around a mid-tropospheric subtropical ridge extending over the northeastern Pacific from the southwestern United States. This feature is expected to steer Juliette west-northwestward at a slightly faster forward motion during the next few days. Toward the end of the forecast period, a westward motion is forecast as Juliette weakens, and likely loses most of its deep convection.

The weakening system will be steered by the low-level easterly flow. The latest track forecast has been shifted slightly to the right of the previous forecast package. This more closely follows the latest trusted guidance, especially the most recent NOAA HFIP HCCA and the TVCE corrected variable consensus model. Cooler oceanic sea surface temperatures, reduced ocean heat content, an intruding dry, stable, surrounding environment, and increasing southwesterly shear should cause steady weakening of the cyclone during the next 5 days.

The latest intensity forecast continues to show a slightly faster weakening trend compared with the previous advisory package. Note that much of the guidance suggests the weakening trend may be even faster than the official forecast.

FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 19.5N 117.1W   85 KT 100 MPH - Category 2 (WSW Puerto Vallarta, Mexico)
 12H  05/0000Z 20.1N 118.2W   80 KT  90 MPH - Category 1 (WSW Cabo San Lucas, Mexico)
 24H  05/1200Z 20.9N 119.8W   75 KT  85 MPH - Category 1 (WSW Cabo San Lucas, Mexico)
 36H  06/0000Z 21.8N 121.5W   65 KT  75 MPH - Category 1 (WSW Cabo San Lucas, Mexico)
 48H  06/1200Z 22.7N 123.5W   55 KT  65 MPH - Tropical Storm (ENE Hilo, Hawaii)
 72H  07/1200Z 23.4N 127.4W   40 KT  45 MPH - Tropical Storm (ENE Hilo, Hawaii)
 96H  08/1200Z 23.0N 131.0W   30 KT  35 MPH - Tropical Depression (ENE Hilo, Hawaii)
120H  09/1200Z 23.0N 135.0W   30 KT  35 MPH - Tropical Depression (ENE Hilo, Hawaii)

Hurricane Juliette – NWS National Hurricane Center Miami FL 300 AM MDT Tue Sep 03 2019

Tropical Storm Juliette has rapidly intensified 50 kt since this time last night, and the recent satellite signature has continued to improve. The initial intensity of 105 kt is based on satellite intensity estimates of T5.5/102 kt from TAFB, SAB, and UW-CIMSS ADT, and also the recently improved eye pattern.

The initial motion estimate is 310/08 kt. A large subtropical ridge located to the north and northeast of Juliette should keep the hurricane moving northwestward today, followed by a turn toward the west-northwest on Wednesday, which should continue into Friday. By day 5, a westward motion is expected to begin as Juliette weakens considerably and becomes steered by the easterly trade wind flow. The new official forecast is a little north or to the right of the previous advisory track, and lies between the consensus models HCCA and TVCE to the north, and FSSE to the south.

Some additional strengthening is forecast with Juliette possibly reaching category 4 status later today or tonight. Thereafter, cold upwelling is expected to begin, which will induce a slow weakening trend on Wednesday. The weakening rate is expected to be tempered by low vertical shear conditions and a very favorable upper-level outflow regime. By day 3 and beyond, however, more significant upwelling is expected to enhance the weakening process, with rapid weakening becoming a distinct possibility on days 4 and 5. The new NHC intensity forecast is similar to the previous advisory and lies slightly above all of the guidance for the next 24 hours, and then closely follows the IVCN and HCCA consensus models on days 2-5.

FORECAST POSITIONS AND MAX WINDS

INIT  03/0900Z 18.2N 114.5W  105 KT 120 MPH - Category 3 (ENE Clarion Island, Mexico)
 12H  03/1800Z 18.7N 115.6W  115 KT 130 MPH - Category 4 (ENE Clarion Island, Mexico)
 24H  04/0600Z 19.2N 116.9W  105 KT 120 MPH - Category 3 (WNW Manzanillo, Mexico)
 36H  04/1800Z 19.7N 118.4W  100 KT 115 MPH - Category 3 (WSW Puerto Vallarta, Mexico)
 48H  05/0600Z 20.4N 120.1W   85 KT 100 MPH - Category 2 (WSW Puerto Vallarta, Mexico)
 72H  06/0600Z 22.0N 124.0W   60 KT  70 MPH - Tropical Storm (WSW Cabo San Lucas, Mexico)
 96H  07/0600Z 23.4N 128.3W   45 KT  50 MPH - Tropical Storm (WSW Puerto San Carlos, Mexico)
120H  08/0600Z 24.0N 132.0W   35 KT  40 MPH - Tropical Storm (WSW Puerto San Carlos, Mexico)

NWS National Hurricane Center Miami FL 300 PM MDT Mon Sep 02, 2019

Tropical Storm  Juliette is clearly on the upswing. A banding eye is present in visible and IR imagery, and satellite intensity estimates around 1800 UTC were all near 65 kt. The IR presentation of the cyclone has continued to improve since then and the initial intensity has been raised to 70 kt,  making Juliette the 5th hurricane of the eastern North Pacific season, and the first hurricane in that basin since July 31.

The hurricane has quickly strengthened today and I see no reason why this won’t continue for the next 12 to 24 hours. Rapid intensification still seems like a distinct possibility, though the intensity guidance certainly suggests otherwise. It is surprising that none of the guidance shows Juliette strengthening very quickly during the next day or two despite the apparently favorable environment the hurricane is embedded within and the current intensification trend. The NHC forecast remains above all of the intensity models for the first 48 hours, given the impressive structure of the hurricane. Beyond that time, the forecast is again close to the multi-model consensus and shows Juliette weakening quickly as it moves over cooler SSTs and into a dry environment.

Juliette has slowed down and the initial motion is now 305/10 kt. There is no change in the forecast reasoning, and Juliette is still generally expected to be steered west-northwestward by an extensive deep-layer ridge located to the north and northeast of the cyclone. The models remain in very good agreement on the forecast of Juliette for the first 3 or 4 days of the forecast, and confidence remains high through that period. The global models then vary on the strength of the ridge and the model spread is notably higher by the end of the forecast. For now, the NHC forecast continues to split the various models and closely follows the multi-model consensus at all times.

FORECAST POSITIONS AND MAX WINDS

INIT  02/2100Z 17.2N 113.3W   70 KT  80 MPH - Tropical Storm (WSW Socorro Island, Mexico)
 12H  03/0600Z 17.9N 114.4W   80 KT  90 MPH - Category 1 (ESE Clarion Island, Mexico)
 24H  03/1800Z 18.6N 115.9W   90 KT 105 MPH - Category 2 (WNW Clarion Island, Mexico)
 36H  04/0600Z 19.1N 117.2W   90 KT 105 MPH - Category 2 (ESE Clarion Island, Mexico)
 48H  04/1800Z 19.6N 118.7W   85 KT 100 MPH - Category 2 (WSW Puerto Vallarta, Mexico)
 72H  05/1800Z 21.1N 122.4W   65 KT  75 MPH - Category 1 (WSW Puerto Vallarta, Mexico)
 96H  06/1800Z 22.5N 127.0W   45 KT  50 MPH - Tropical Storm (WSW Cabo San Lucas, Mexico)
120H  07/1800Z 24.0N 131.0W   35 KT  40 MPH - Tropical Storm (WSW Cabo San Lucas, Mexico)

NWS National Hurricane Center Miami FL 900 AM MDT Sun Sep 01 2019

At 900 AM MDT (1500 UTC), the center of Tropical Storm Juliette was located near latitude 14.3 North, longitude 108.8 West. Juliette is moving toward the northwest near 14 mph (22 km/h), and this general motion is expected to continue today. A turn toward the west-northwest with an increase in forward speed is expected by Monday and this general motion is forecast through Wednesday.

Maximum sustained winds have increased to near 60 mph (95 km/h) with higher gusts. Juliette is expected to become a hurricane tomorrow and continue to intensify on Tuesday. Weakening could begin on Wednesday.

Tropical-storm-force winds extend outward up to 80 miles (130 km) from the center.

NWS National Hurricane Center Miami FL 900 AM MDT Sun Sep 01 2019

Tropical Storm Juliette has been quickly organizing this morning. Satellite and microwave data indicate that a small central dense overcast has formed, with a large band on the east side. The current wind speed is set to 50 kt, in line with the recent CIMSS objective Dvorak estimate since the subjective estimates are still catching up with this storm.

There’s been a significant change to the intensity and size forecasts of Juliette this morning, with guidance now showing a stronger and larger hurricane in about a day. This is consistent with the recent development of the early stages of an inner core, which would allow Juliette to continue to intensify at a fast pace. Indeed, rapid intensification is a distinct possibility due to an environment of low shear and very warm water, and the various rapid intensification indices are all showing this chance. Thus the forecast is raised from the last one, similar to the corrected consensus guidance and further upward adjustments might be required this afternoon.

Fixes show that the storm is moving faster to the northwest this morning. A ridge to the northeast of Juliette should steer the storm on this general path for the next several days, followed by a slight turn toward the west-northwest at the end.

FORECAST POSITIONS AND MAX WINDS

INIT  01/1500Z 14.3N 108.8W   50 KT  60 MPH - Tropical Storm (ESE Acapulco, Mexico)
 12H  02/0000Z 15.3N 110.3W   60 KT  70 MPH - Tropical Storm (ESE Socorro Island, Mexico)
 24H  02/1200Z 16.5N 112.3W   75 KT  85 MPH - Category 1 (WSW Clarion Island, Mexico)
 36H  03/0000Z 17.4N 114.1W   85 KT 100 MPH - Category 2 (ESE Clarion Island, Mexico)
 48H  03/1200Z 18.1N 115.6W   90 KT 105 MPH - Category 2 (WSW Clarion Island, Mexico)
 72H  04/1200Z 19.2N 118.5W   75 KT  85 MPH - Category 1 (WSW Manzanillo, Mexico)
 96H  05/1200Z 20.5N 121.8W   70 KT  80 MPH - Category 1 (WSW Puerto Vallarta, Mexico)
120H  06/1200Z 22.5N 125.5W   60 KT  70 MPH - Category 1 (WSW Cabo San Lucas, Mexico)

If this storm system is named, it will be Tropical Storm Juliette.

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