Tropical Storm Cristina

Tropical Storm Cristina Track 1600 Hours July 7 2020
Tropical Storm Cristina Track 1600 Hours July 7 2020

Tropical Storm Cristina Wind SpeedTropical Storm Cristina NWS National Hurricane Center Miami FL 400 PM CDT Tue Jul 07 2020 (see Tuesday video below)

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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Video: Tropical Storm Cristina , Advisory #4!

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