Tropical Storm Cristina

Tropical Storm Cristina Track 0800 Hours July 12 2020
Tropical Storm Cristina Track 0800 Hours July 12 2020

Tropical Storm Cristina Wind SpeedsTropical Storm Cristina NWS National Hurricane Center Miami FL 800 AM PDT Sun Jul 12, 2020

Cristina’s convective pattern continues to rapidly erode with only a small patch of moderate convection remaining in the northeastern quadrant. Based on overnight scatterometer winds of 39 kt and the significant decrease in convection since that time, it is assumed that additional vortex spindown has occurred over 23 deg C water, and the initial intensity is therefore decreased to 35 kt, which is also supported by a blend of the latest CI-satellite intensity estimates from TAFB and SAB.

Cristina is moving westward or 280/11 kt. There are no significant changes to the previous forecast track or rationale. The latest NHC model guidance remains tightly packed about the previous forecast track, with Cristina expected to continue in a general westerly direction until dissipation occurs in 72-96 h over the extreme eastern portion of the Central Pacific basin.

Cristina should continue to spin down as the cyclone moves over near 22 deg C SSTs, becoming a remnant low in about 24 hours. It is possible that Cristina could degenerate into an open wave sooner than currently forecast due to the abundance of dry, stable air that the cyclone will be ingesting. The new NHC intensity forecast is similar to the previous advisory and closely follows the IVCN intensity consensus model.

FORECAST POSITIONS AND MAX WINDS

INIT  12/1500Z 20.7N 124.4W   35 KT  40 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 12H  13/0000Z 20.9N 126.2W   30 KT  35 MPH - Depression (WSW Cabo San Lucas, MX)
 24H  13/1200Z 21.3N 128.7W   25 KT  30 MPH - Low (WSW Cabo San Lucas, MX)
 36H  14/0000Z 21.9N 131.2W   20 KT  25 MPH - Low (WSW Cabo San Lucas, MX)
 48H  14/1200Z 22.4N 133.8W   20 KT  25 MPH - Low (WSW Cabo San Lucas, MX)
 60H  15/0000Z 22.8N 136.4W   20 KT  25 MPH - Low (WNW Hilo, Hawaii)
 72H  15/1200Z 23.3N 139.2W   20 KT  25 MPH - Low (WNW Hilo, Hawaii)
 96H  16/1200Z...DISSIPATED

NWS National Hurricane Center Miami FL 500 AM HST Sat Jul 11, 2020 

Over the past several hours, the coverage of deep convection around the center of Cristina has gradually decreased as the cyclone continues to move over relatively cool 24 C waters. The latest satellite intensity estimates from TAFB, SAB, and the UW-CIMSS SATCON all support lowering the initial intensity to 55 kt.

Cristina is forecast to move over even cooler waters and into a progressively drier and more stable air mass over the next couple of days. These conditions should cause the cyclone to steadily weaken. By 60 h, Cristina is forecast to have lost its deep convection near its center and become a remnant low. There is a chance that the convection could dissipate sooner than indicated, and Cristina could become a post-tropical cyclone while wind speeds are still greater than 30 kt. The NHC intensity forecast is largely an update of the previous one.

Cristina is moving just north of due west at 12 kt. This motion is expected to continue for the next several days, as the cyclone is steered by a mid-level ridge centered over the southwestern U.S. early on, then by the low level easterlies once the system becomes a remnant low. The NHC forecast lies in the middle of tightly clustered track guidance, and is little changed from the previous forecast.

FORECAST POSITIONS AND MAX WINDS

INIT  11/1500Z 20.6N 119.7W   55 KT  65 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 12H  12/0000Z 20.9N 121.6W   50 KT  60 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 24H  12/1200Z 21.2N 123.9W   45 KT  50 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 36H  13/0000Z 21.6N 126.2W   40 KT  45 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 48H  13/1200Z 22.1N 128.7W   35 KT  40 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 60H  14/0000Z 22.6N 131.4W   30 KT  35 MPH - Low (ENE Hilo, Hawaii)
 72H  14/1200Z 23.1N 133.9W   30 KT  35 MPH - Low (ENE Hilo, Hawai)
 96H  15/1200Z 23.8N 139.2W   25 KT  30 MPH - Low (ENE Hilo, Hawai)
120H  16/1200Z 24.0N 144.0W   20 KT  25 MPH. - Low (ENE Hilo, Hawai)

NWS National Hurricane Center Miami FL 900 AM MDT Fri Jul 10, 2020

Cristina’s appearance on satellite has not improved over the past several hours. In fact, cloud tops are beginning to warm and some of the convection has begun to erode over the northern portion of the circulation. A blend of the satellite intensity estimates from TAFB and SAB support keeping the initial intensity at 60 kt. However, this may be a little generous due to the lower values suggested by the objective satellite intensity estimates as well as an earlier ASCAT pass showing maximum winds of only 45 kt.

It is becoming less likely that Cristina will become a hurricane as the storm is forecast to cross the 26 C SST isotherm later today and move into a drier and more stable air mass. Once the cyclone enters this unfavorable environment a weakening trend should begin. By 72 h, Cristina is expected to become a remnant low. The NHC intensity forecast was adjusted slightly downward in the near term, and no longer shows Cristina reaching hurricane strength. The remainder of the intensity forecast is similar to the previous official forecast.

The storm is moving west-northwestward at about 12 kt. A mid-level ridge centered over the southwestern U.S. should continue to steer Cristina to the west-northwest through tonight. As Cristina weakens and becomes a shallow system, a gradual turn toward the west is expected in the low-level flow. The track models remain tightly clustered, and only minor changes were made to the previous NHC forecast.

FORECAST POSITIONS AND MAX WINDS

INIT  10/1500Z 19.1N 114.2W   60 KT  70 MPH - Tropical Storm (WNW Isla Socorro, MX)
 12H  11/0000Z 19.8N 116.2W   60 KT  70 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 24H  11/1200Z 20.3N 118.9W   55 KT  65 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 36H  12/0000Z 20.6N 121.5W   50 KT  60 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 48H  12/1200Z 20.9N 124.0W   45 KT  50 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 60H  13/0000Z 21.2N 126.5W   40 KT  45 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 72H  13/1200Z 21.6N 128.9W   30 KT  35 MPH - Low (ENE Hilo, Hawaii)
 96H  14/1200Z 22.5N 134.0W   25 KT  30 MPH - Low (ENE Hilo, Hawaii)
120H  15/1200Z 22.8N 139.1W   25 KT  30 MPH - Low (ENE Hilo, Hawaii)

NWS National Hurricane Center Miami FL 900 PM MDT Thu Jul 09, 2020

Cristina’s satellite presentation has degraded somewhat during the past several hours, with deep convection on the wane and some evidence of dry air near the center. Still, microwave data does show a large banding pattern with a mid-level core present, suggesting there might be more than meets the eye than just conventional satellite imagery. The current intensity of the storm is difficult to ascertain, as estimates from generally credible techniques range from 45 kt to 77 kt on this package. It is probably best to keep the initial wind speed 60 kt for now, and we will see if the intensity becomes more clear overnight.

The storm has about a day over marginally warm waters in light shear conditions before SSTs begin to cool, and eventually more significant dry air is entrained into the inner core. Thus some strengthening is anticipated on Friday, and Cristina should start a gradual weakening over the weekend through early next week. The cyclone should have a challenging time producing convection over sub-23C waters, which happens in about 72 hours, so that is the time chosen for post-tropical transition. This is earlier than the previous forecast and best matches a GFS/ECMWF blend. No significant changes were made to the intensity forecast with guidance in good agreement at this time.

Christina continues moving west-northwestward at about 10 kt. A mid-level ridge centered over the southwestern U.S. is expected to strengthen over the next day or so, which should force the storm in a similar direction but with a slight increase in forward speed. Over the weekend, as the cyclone weakens, a gradual turn to the west is expected. The forecast track is a little slower than the previous one at long range, otherwise the track is basically an update of the earlier track prediction.

FORECAST POSITIONS AND MAX WINDS

INIT  10/0300Z 18.4N 111.9W   60 KT  70 MPH - Tropical Storm (ESE Isla Socorro, MX)
 12H  10/1200Z 19.1N 113.5W   65 KT  75 MPH - Category 1 (ESE Isla Socorro, MX)
 36H  11/1200Z 20.8N 118.9W   55 KT  65 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 48H  12/0000Z 21.3N 121.7W   45 KT  50 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 60H  12/1200Z 21.6N 124.4W   40 KT  45 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 72H  13/0000Z 21.8N 127.0W   35 KT  40 MPH - Depression (WSW Cabo San Lucas, MX)
 96H  14/0000Z 22.2N 132.3W   25 KT  30 MPH - Low (WSW Cabo San Lucas, MX)
120H  15/0000Z 22.5N 138.0W   25 KT  30 MPH - Low (WSW Cabo San Lucas, MX)

NWS National Hurricane Center Miami FL 300 PM MDT Thu Jul 09, 2020

Satellite images and microwave data indicate that the structure of Cristina has improved since this morning. Banding features have become more prevalent, while deep convection has persisted over the center throughout the day. In addition, the average of the satellite intensity estimates from TAFB and SAB has increased since this morning’s advisory. Therefore, the initial intensity has been raised to 60 kt.

The storm will remain in a favorable environment for intensification through Friday morning, and it is expected to become a hurricane by that time. By late Friday, the cyclone will cross the 26 C isotherm and move into a progressively more stable and dry atmospheric environment. This should result in steady weakening. There is some spread in the guidance as to how quickly Cristina will lose its convection later on in the forecast period. The GFS suggests this will not occur until 120 h, while the Canadian and ECMWF indicate this will happen in 96 h and 72 h, respectively. Based on a blend of these, Cristina is now expected to become a remnant low by 96 h. The NHC intensity forecast is very similar to the previous one and is close to the consensus aids.

Cristina’s initial motion is west-northwest at 10 kt. The mid-level ridge centered over the southwestern U.S. is expected to strengthen a little over the next day or so, which should keep Cristina on the same path but with a slight increase in forward speed. Over the weekend, as the cyclone weakens, a gradual turn to the west is expected. The guidance shifted slightly northward beyond day 3, so the NHC track forecasted was nudged a little north for that time frame. Otherwise, the latest NHC track forecast is little changed compared to the previous one.

FORECAST POSITIONS AND MAX WINDS

INIT  09/2100Z 17.9N 111.1W   60 KT  70 MPH - Tropical Storm (ESE Isla Socorro, MX)
 12H  10/0600Z 18.7N 112.6W   65 KT  75 MPH - Category 1 (ESE Isla Socorro, MX)
 24H  10/1800Z 19.7N 115.0W   65 KT  75 MPH - Category 1 (WSW Cabo San Lucas, MX)
 36H  11/0600Z 20.5N 117.8W   60 KT  70 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 48H  11/1800Z 21.0N 120.7W   55 KT  65 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 60H  12/0600Z 21.4N 123.5W   45 KT  50 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 72H  12/1800Z 21.5N 126.3W   40 KT  45 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 96H  13/1800Z 21.9N 131.9W   30 KT  35 MPH - Low (ENE Hilo, Hawaii)
120H  14/1800Z 22.3N 137.3W   25 KT  30 MPH - Low (ENE Hilo, Hawaii)

NWS National Hurricane Center Miami FL 900 AM MDT Thu Jul 09, 2020

Cristina’s convective structure has evolved into a large curved band over the past several hours. The improving appearance has not yet materialized in an increase in intensity, but may be indicative that some strengthening may soon occur. The initial wind speed estimate of 55 kt, is based on the most recent TAFB Dvorak satellite intensity estimate.

The storm will remain in a favorable environment for intensification for another 24 h or so. And, with the convective structure beginning to show some improvement, it is reasonable to assume that some strengthening is likely through tonight. After 24 h, the cyclone will cross the 26 C isotherm and move into a progressively more stable and dry atmospheric environment. This should result in steady weakening. By 120 h, Cristina is expected to have lost all of its deep convection and become a remnant low. The official forecast is essentially an update of the previous one, indicating that Cristina should become a hurricane by tomorrow morning and then begin to weaken shortly thereafter.

Cristina’s initial motion is west-northwest at 9 kt. A mid-level ridge centered over the southwestern U.S. is expected to strengthen a little over the next day or so, which should keep Cristina on the same path but with a slight increase in forward speed. Over the weekend, as the cyclone weakens, a gradual turn to the west is expected. The latest NHC track forecast is very similar to the previous one, and is in the middle of tightly clustered guidance.

FORECAST POSITIONS AND MAX WINDS

INIT  09/1500Z 17.4N 110.2W   55 KT  65 MPH - Tropical Storm (ESE Isla Socorro, MX)
 12H  10/0000Z 18.2N 111.6W   60 KT  70 MPH - Tropical Storm (ESE Isla Socorro, MX)
 24H  10/1200Z 19.2N 113.8W   65 KT  75 MPH - Category 1 (WNW Isla Socorro, MX)
 36H  11/0000Z 20.1N 116.6W   60 KT  70 MPH - Tropical Storm (WNW Isla Socorro, MX)
 48H  11/1200Z 20.7N 119.5W   55 KT  65 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 60H  12/0000Z 21.1N 122.5W   50 KT  60 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 72H  12/1200Z 21.2N 125.5W   45 KT  50 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 96H  13/1200Z 21.4N 131.3W   35 KT  40 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
120H  14/1200Z 21.5N 137.0W   25 KT  30 MPH - Low (WSW Cabo San Lucas, MX)

NWS National Hurricane Center Miami FL 300 AM MDT Thu Jul 09, 2020

Although deep convection has been increasing tonight in association with Cristina, the overall cloud pattern and structure of the storm has changed little and it continues to lack banding features. The satellite intensity estimates range from 45 to 60 kt, and a recent ASCAT pass showed maximum winds of around 40 kt. Based on these data, the initial intensity is held at a possibly generous 55 kt.

Cristina has not strengthened as much as anticipated. However, the storm still has about another 36 hours in favorable environmental conditions of wind shear of 10 kt or less, mid-level humidities between 75 and 80 percent, and SSTs of 26 C or warmer. During that period it still seems likely that Cristina will strengthen and it could become a hurricane. After 36 hours, Cristina is expected to move over much cooler waters and into a notably drier and more stable air mass. These conditions should promote a steady weakening trend, and Cristina will likely become a remnant low in 4 or 5 days. The NHC intensity forecast is a little lower than the previous one and in good agreement with the IVCN consensus model.

The storm is moving west-northwestward at about 10 kt. A mid-level ridge located over the southwestern U.S. is expected to strengthen in place, and that should cause Cristina to move a little faster to the west-northwest during the next few days. After that time, the weaker and likely vertically shallow storm should turn toward the west in the low-level trade wind flow. The model tracks remain tightly packed, and the new NHC track forecast is largely an update of the previous one.

FORECAST POSITIONS AND MAX WINDS

INIT  09/0900Z 16.8N 109.4W   55 KT  65 MPH - Tropical Storm (WSW Acapulco, MX)
 12H  09/1800Z 17.6N 110.8W   60 KT  70 MPH - Tropical Storm (WSW Acapulco, MX)
 24H  10/0600Z 18.6N 112.9W   65 KT  75 MPH - Category 1 (WSW Isla Socorro, MX)
 36H  10/1800Z 19.6N 115.3W   65 KT  75 MPH - Category 1 (WSW Isla Socorro, MX)
 48H  11/0600Z 20.3N 118.2W   60 KT  70 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 60H  11/1800Z 20.9N 121.2W   50 KT  60 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 72H  12/0600Z 21.1N 124.1W   45 KT  50 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 96H  13/0600Z 21.2N 129.7W   35 KT  40 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
120H  14/0600Z 21.4N 135.2W   25 KT  30 MPH - Low(WSW Hilo, Hawaii)

NWS National Hurricane Center Miami FL 900 PM MDT Wed Jul 08, 2020

After the earlier convective hiatus, Cristina is now going through a little bit of a bursting phase with new inner-core convection developing just west of the center, with the latter feature showing up quite nicely in 0139 UTC SSMI/S microwave satellite imagery. The intensity has been increased to 55 kt based on satellite classifications of T3.5/55 kt from TAFB, and 57 kt and 59 kt from UW-CIMSS ADT and SATCON, respectively.

Cristina is moving northwestward or 305/11 kt. The strong subtropical ridge to the north and northeast of the tropical cyclone should keep Cristina moving in that general direction tonight, followed by a turn toward the west-northwest at about the same forward speed by Thursday morning. By 96 h and beyond, a rapidly weakening and vertically shallow Cristina should turn westward under the influence of brisk easterly trade wind flow. The latest NHC model guidance remains in strong agreement on this evolving track scenario, and the new track forecast closely follows the tightly packed consensus models, which are a little south of the previous advisory track.

Environmental and oceanic conditions are expected to remain conducive for strengthening during the next 36-48 h while Cristina remains over SSTs greater than 26 deg C. By 72 h and beyond, the cyclone will be moving over much cooler water characterized by SSTs near 22C by 96-120h, which is expected to induce steady weakening despite the low vertical wind shear conditions. The new NHC intensity forecast is similar to the previous advisory and the IVCN intensity consensus, with Cristina still expected to become a hurricane by late Thursday or early Friday.

FORECAST POSITIONS AND MAX WINDS

INIT  09/0300Z 16.4N 108.6W   55 KT  65 MPH - Tropical Storm (WSW Acapulco, MX)
 12H  09/1200Z 17.3N 110.0W   60 KT  70 MPH - Tropical Storm (WSW Acapulco, MX)
 24H  10/0000Z 18.3N 111.9W   65 KT  75 MPH - Category 1 (WSW Acapulco, MX)
 36H  10/1200Z 19.2N 114.1W   70 KT  80 MPH - Category 1 (WSW Acapulco, MX)
 48H  11/0000Z 20.0N 116.7W   70 KT  80 MPH - Category 1 (WSW Isla Socorro, MX)
 60H  11/1200Z 20.6N 119.6W   65 KT  75 MPH - Category 1 (WSW Isla Socorro, MX)
 72H  12/0000Z 21.0N 122.4W   50 KT  60 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 96H  13/0000Z 21.2N 127.8W   35 KT  40 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
120H  14/0000Z 21.6N 133.7W   25 KT  30 MPH - Low ()

NWS National Hurricane Center Miami FL 900 AM MDT Wed Jul 08, 2020 

First light satellite images show that the convective organization of Cristina is gradually improving, while banding features are developing across the northern portion of the circulation. The center remains underneath the northeastern side of the main area of convection due to moderate shear, but this shear appears to be diminishing. The initial intensity has been increased to 50 kt, which is a blend of the subjective Dvorak intensity estimates from TAFB and SAB.

Cristina turned to the northwest and slowed down to about 10 kt this morning. A turn back toward the west-northwest is expected to occur later today or tonight, and this motion is forecast to continue for the next few days as the cyclone is steered by a large ridge centered over the southwestern United States. Later in the forecast period, a turn to the west is expected as the weakening cyclone becomes steered by the low-level easterlies. The track guidance is tightly clustered, and the NHC forecast lies near the middle of the envelope.

The decreasing shear over Cristina combined with warm SSTs and a moist air mass should allow the cyclone to intensify over the next couple of days. After that time, the system will cross over the 26 C isotherm and enter into a drier and more stable atmospheric environment. This should cause a steady weakening trend to begin after 48 h. Although the forecast still shows Cristina as a tropical storm in 5 days, it is possible all of the deep convection would have dissipated by that time. The latest NHC forecast is very close to the intensity consensus aids.

FORECAST POSITIONS AND MAX WINDS

INIT  08/1500Z 14.6N 106.9W   50 KT  60 MPH - Tropical Storm (WSW Acapulco, MX)
 12H  09/0000Z 15.4N 108.2W   55 KT  65 MPH - Tropical Storm (WSW Acapulco, MX)
 24H  09/1200Z 16.6N 110.1W   65 KT  75 MPH - Category 1 (WSW Acapulco, MX)
 36H  10/0000Z 17.6N 112.1W   70 KT  80 MPH - Category 1 (WSW Isla Socorro, MX)
 48H  10/1200Z 18.5N 114.1W   75 KT  85 MPH - Category 1 (WNW Isla Socorro, MX)
 60H  11/0000Z 19.5N 116.5W   70 KT  80 MPH - Category 1 (WSW Cabo San Lucas, MX)
 72H  11/1200Z 20.2N 119.1W   60 KT  70 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
 96H  12/1200Z 21.0N 124.5W   45 KT  50 MPH - Tropical Storm (WSW Cabo San Lucas, MX)
120H  13/1200Z 21.5N 130.5W   35 KT  40 MPH - Tropical Storm (WSW Cabo San Lucas, MX)

NWS National Hurricane Center Miami FL 400 PM CDT Tue Jul 07, 2020

Cristina is still being affected by some northeasterly vertical wind shear as visible satellite imagery shows that the center is located near the northeastern edge of the large curved convective band. The various subjective and objective satellite intensity estimates range from 35 to 45 kt, and a recent ASCAT overpass revealed a small area of 35-40 kt wind vectors near the center. Based on these data, the initial intensity is set at 40 kt. The moderate vertical wind shear over the system is forecast to abate over the next 12-24 hours. This, along with SSTs of 28-29C, should allow for strengthening and Cristina is still forecast to become a hurricane in a day or two. Although Cristina has not strengthened as much as anticipated over the past 24 hours, with the more favorable atmospheric conditions anticipated beginning Wednesday, a period of steady to rapid strengthening is still possible. The latest intensity guidance shows a slightly lower peak wind speed than before, so the new NHC intensity forecast has been nudged in that direction. After 72 hours, Cristina will be moving over cooler waters and steady weakening is expected later in the period.

Satellite fixes show that Cristina is moving west-northwestward or 305/11 kt. There has been no significant change to the track foreast reasoning. Cristina should continue on a west-northwestward heading over the next several days to the south of a large mid-level ridge over the southwestern United States. The overall track guidance envelop has shifted slightly northward, so the NHC track forecast has been adjusted accordingly. The new track forecast lies between the previous official foreast and the most recent consensus aids.

FORECAST POSITIONS AND MAX WINDS

INIT  07/2100Z 13.0N 103.8W   40 KT  45 MPH - Tropical Storm (WSW Acapulco, MX)
 12H  08/0600Z 13.8N 105.3W   45 KT  50 MPH - Tropical Storm (WSW Acapulco, MX)
 24H  08/1800Z 15.0N 107.2W   55 KT  65 MPH - Tropical Storm (WSW Acapulco, MX)
 36H  09/0600Z 16.1N 109.2W   65 KT  75 MPH - Category 1 (WSW Acapulco, MX)
 48H  09/1800Z 17.0N 110.9W   75 KT  85 MPH - Category 1 (WSW Acapulco, MX)
 60H  10/0600Z 18.0N 112.7W   85 KT 100 MPH - Category 2 (WSW Isla Socorro, MX)
 72H  10/1800Z 19.0N 114.9W   85 KT 100 MPH - Category 2 (WNW Isla Socorro, MX)
 96H  11/1800Z 20.5N 119.8W   70 KT  80 MPH - Category 1 (WSW Cabo San Lucas, MX)

NWS National Hurricane Center Miami FL 400 AM CDT Tue Jul 07, 2020

Deep convection is gradually expanding over the center of Cristina and in curved bands over the western portion of the circulation. An ASCAT-B overpass from around 0430 UTC showed maximum winds of around 35 kt. Based on that data and Dvorak estimates of T2.5/35 kt from TAFB, SAB, and automated values from CIMSS at the University of Wisconsin, the initial wind speed is held at 35 kt.

Cristina is expected to strengthen during the next few days due to the favorable environmental conditions of low wind shear and warm SSTs, and its developing compact inner core as observed in satellite data. The only limiting factor is some dry air that has entrained into the eastern portion of the circulation. However, given the largely conducive conditions for strengthening, the NHC intensity forecast lies at the high end of the model guidance during the next 3 days. Although it is not explicitly forecast, rapid intensification could occur sometime during the next couple of days. Cristina will likely be moving over SSTs below 26 C and into a drier and more stable air mass late this week and this weekend, and that should induce a weakening trend. This intensity forecast is mostly an update of the previous one and in best agreement with corrected consensus model HCCA.

Satellite fixes indicate that Cristina is moving west-northwestward at about 11 kt. The track forecast reasoning is fairly straightforward. A mid-level ridge centered over the southwestern U.S. is expected to strengthen in place during the next several days. This should keep Cristina on a west-northwestward path well offshore of Mexico through the remainder of the week and into this weekend. Only minor changes were made to the previous NHC track forecast, and this prediction lies near the middle of the guidance envelope.

FORECAST POSITIONS AND MAX WINDS

INIT  07/0900Z 11.5N 102.4W   35 KT  40 MPH - Tropical Storm (WSW Acapulco, MX)
 12H  07/1800Z 12.2N 104.1W   45 KT  50 MPH - Tropical Storm (WSW Acapulco, MX)
 24H  08/0600Z 13.3N 106.3W   55 KT  65 MPH - Tropical Storm (WSW Acapulco, MX)
 36H  08/1800Z 14.3N 108.1W   70 KT  80 MPH - Category 1 (WSW Acapulco, MX)
 48H  09/0600Z 15.3N 109.8W   80 KT  90 MPH - Category 1 (WSW Acapulco, MX)
 60H  09/1800Z 16.3N 111.7W   90 KT 105 MPH - Category 2 (ESE Isla Socorro, MX)
 72H  10/0600Z 17.3N 113.6W   90 KT 105 MPH - Category 2 (WSW Isla Socorro, MX)
 96H  11/0600Z 18.9N 117.4W   80 KT  90 MPH - Category 1 (ENE Isla Socorro, MX)
120H  12/0600Z 20.5N 122.5W   65 KT  75 MPH - Category 1 (WSW Cabo San Lucas, MX)

NWS National Hurricane Center Miami FL 1000 PM CDT Mon Jul 06, 2020

Satellite imagery indicates that convection has increased and become better organized since the previous advisory, although convection has waned somewhat during the past couple of hours due to entrainment of dry mid-level air. A 2213Z SSMI overpass showed a small but well-defined mid-level eye feature in the 85 GHz data and the latest TAFB satellite classification was T2.0/30 kt. Based on the improved banding features and the mid-level eye, the intensity has been increased to a conservative 35 kt.

The initial motion estimate is 300/13 kt, based on a blend of TAFB and microwave satellite fixes. Cristina is expected to be steered west-northwestward throughout the forecast period along the southern periphery of a large deep-layer ridge that extends westward from the south-central and southwestern United States. The latest NHC model guidance has become more tightly packed around the previous forecast track, so only minor tweaks were made in the form of a slightly faster forward speed. The NHC track forecast lies close to the simple consensus models, which are a little south of the corrected-consensus model HCCA.

Cristina is expected to remain in quite favorable environmental and oceanic conditions for the next 72 h or so. The small inner-core eye-like feature and the expected low vertical shear and impressive upper-level outflow conditions suggest that rapid intensification (RI) could occur at some point occur during that time. However, recent entrainment of dry mid-level air into the eastern semicircle has eroded convection in that part of the circulation, and the dry air may have even penetrated into and disrupted the inner core itself. Given the aforementioned uncertainty in the structure of the cyclone, RI is not being explicitly forecast at this time, although the official intensity forecast is higher than the previous advisory through 96 h. By 120 h, significant weakening should be well underway when Cristina will be moving over 24-deg-C sea-surface temperatures. The NHC official intensity forecast follows the trend of the previous forecast, and there is a distinct possibility that Cristina could undergo RI and also become a major hurricane if the inner-core region has not been disrupted.

ORECAST POSITIONS AND MAX WINDS

INIT  07/0300Z 11.2N 101.3W   35 KT  40 MPH - Tropical Storm (WSW Acapulco, MX)
 12H  07/1200Z 11.9N 103.0W   45 KT  50 MPH - Tropical Storm (WSW Acapulco, MX)
 24H  08/0000Z 12.9N 105.3W   55 KT  65 MPH - Tropical Storm (WSW Acapulco, MX)
 36H  08/1200Z 13.9N 107.3W   70 KT  80 MPH - Category 1 (WSW Acapulco, MX)
 48H  09/0000Z 14.8N 109.0W   80 KT  90 MPH - Category 1 (WSW Acapulco, MX)
 60H  09/1200Z 15.7N 110.7W   90 KT 105 MPH - Category 2 (ESE Isla Socorro, MX)
 72H  10/0000Z 16.5N 112.3W   95 KT 110 MPH - Category 2 (WSW Isla Socorro, MX)
 96H  11/0000Z 18.1N 116.1W   85 KT 100 MPH - Category 1 (WSW Cabo San Lucas, MX)
120H  12/0000Z 19.9N 121.6W   70 KT  80 MPH - Category 1 (WSW Cabo San Lucas, MX)

NWS National Hurricane Center Miami FL 400 PM CDT Mon Jul 06, 2020 

Satellite imagery shows that deep convection associated with the low-pressure area south of Mexico has become significantly better organized since this morning. ASCAT data from earlier this afternoon suggested that the circulation was still somewhat elongated, but since that time low cloud motions indicate that the circulation has become better defined. The scatterometer data also revealed believable wind vectors of at least 30 kt, with higher rain-inflated vectors within the deep convection. Based on these data, advisories are being initiated on a 30-kt tropical depression at this time.

The depression is located within a favorable environment consisting of low vertical wind shear, warm sea-surface temperatures, and a moist atmosphere. As a result, steady strengthening is anticipated over the next several days, and the NHC forecast calls for the cyclone to become a hurricane in about 48 hours. The NHC intensity forecast is in best agreement with the intensity consensus aids IVCN and HCCA, but is not quite as bullish as the SHIPS guidance. Given the anticipated low wind shear conditions over the next few days, a period of rapid strengthening is possible, and this intensity forecast could be somewhat conservative. The cyclone is expected to move over cooler waters in about 96 hours, which should cause weakening by the end of the period.

Since the depression is still in its formative stage, the initial motion is a somewhat uncertain 295/11 kt. The depression is being steered west-northwestward to the south of a large mid-level ridge located over the south-central United States. A general west-northwestward heading about around the same forward speed is expected over the next several days. The dynamical model guidance is in fairly good agreement on this scenario and the NHC track forecast lies near the various consensus aids.

FORECAST POSITIONS AND MAX WINDS

INIT  06/2100Z 10.5N  99.7W   30 KT  35 MPH - Depression (WSW Acapulco, MX)
 12H  07/0600Z 11.2N 101.1W   35 KT  40 MPH - Tropical Storm (WSW Acapulco, MX)
 24H  07/1800Z 12.1N 103.4W   45 KT  50 MPH - Tropical Storm (WSW Acapulco, MX)
 36H  08/0600Z 13.0N 105.5W   55 KT  65 MPH - Tropical Storm (WSW Acapulco, MX)
 48H  08/1800Z 14.1N 107.4W   65 KT  75 MPH - Category 1 (WSW Acapulco, MX)
 60H  09/0600Z 15.0N 109.0W   75 KT  85 MPH - Category 1 (WSW Acapulco, MX)
 72H  09/1800Z 15.7N 110.7W   85 KT 100 MPH - Category 2 (ESE Isla Socorro, MX)
 96H  10/1800Z 17.2N 114.1W   85 KT 100 MPH - Category 2 (WSW Isla Socorro, MX)
120H  11/1800Z 18.8N 118.7W   70 KT  80 MPH - Category 1 (WSW Cabo San Lucas, MX)

NWS National Hurricane Center Miami FL 500 AM PDT Mon Jul 6, 2020

For the eastern North Pacific…east of 140 degrees west longitude:

1. Shower and thunderstorm activity associated with a broad area of low pressure located several hundred miles south-southeast of Acapulco, Mexico, have increased in coverage overnight. Environmental conditions are expected to be conducive for development over the next several days, and a tropical depression is likely to form within the next two or three days while the system moves west-northwestward, well south of the coast of southern Mexico. * Formation chance through 48 hours…medium…60 percent. * Formation chance through 5 days…high…90 percent.

NWS National Hurricane Center Miami FL 500 PM PDT Sun Jul 5, 2020 

For the eastern North Pacific…east of 140 degrees west longitude:

  • 1. An elongated area of low pressure located several hundred miles south-southwest of the southern tip of the Baja California peninsula continues to produce a large area of disorganized showers and a few thunderstorms. Any development of this system should be slow to occur over the next couple of days while it moves slowly west-northwestward. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…20 percent.
  • 2. A broad low pressure system located several hundred miles south and south-southwest of the Gulf of Tehuantepec is producing a large but disorganized area of showers and thunderstorms. However, environmental conditions are expected to be conducive for development over the next several days, and a tropical depression is likely to form by the middle of the week while the system moves west-northwestward, well south of the coast of southern Mexico. * Formation chance through 48 hours…medium…40 percent. * Formation chance through 5 days…high…90 percent.

NWS National Hurricane Center Miami FL 500 AM PDT Sun Jul 5, 2020 

For the eastern North Pacific…east of 140 degrees west longitude:

  • 1. An elongated area of low pressure located several hundred miles south-southwest of the southern tip of the Baja California peninsula continues to produce a large area of showers and thunderstorms. Slow development of this system is possible during the next few days while it moves west-northwestward at about 10 mph. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…30 percent.
  • 2. An area of disturbed weather has formed several hundred miles south-southwest of the Gulf of Tehuantepec. Environmental conditions are expected to be conducive for gradual development over the next several days, and a tropical depression is likely to form by the middle of next week while the system moves west-northwestward, well south of the coast of southern Mexico. * Formation chance through 48 hours…low…near 20 percent. * Formation chance through 5 days…high…80 percent.

If this storm is named, it will be Tropical Storm Cristina

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