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Tropical Storm Cristina Forecast Discussion Number 3

2020-07-07 10:31:38| National Hurricane Center (East Pacific)

Issued at 400 AM CDT Tue Jul 07 2020 000 WTPZ45 KNHC 070831 TCDEP5 Tropical Storm Cristina Discussion Number 3 NWS National Hurricane Center Miami FL EP052020 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 12H 07/1800Z 12.2N 104.1W 45 KT 50 MPH 24H 08/0600Z 13.3N 106.3W 55 KT 65 MPH 36H 08/1800Z 14.3N 108.1W 70 KT 80 MPH 48H 09/0600Z 15.3N 109.8W 80 KT 90 MPH 60H 09/1800Z 16.3N 111.7W 90 KT 105 MPH 72H 10/0600Z 17.3N 113.6W 90 KT 105 MPH 96H 11/0600Z 18.9N 117.4W 80 KT 90 MPH 120H 12/0600Z 20.5N 122.5W 65 KT 75 MPH $$ Forecaster Cangialosi

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Tropical Storm Cristina Forecast Discussion Number 2

2020-07-07 04:32:31| National Hurricane Center (East Pacific)

Issued at 1000 PM CDT Mon Jul 06 2020 031 WTPZ45 KNHC 070232 TCDEP5 Tropical Storm Cristina Discussion Number 2 NWS National Hurricane Center Miami FL EP052020 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. FORECAST POSITIONS AND MAX WINDS INIT 07/0300Z 11.2N 101.3W 35 KT 40 MPH 12H 07/1200Z 11.9N 103.0W 45 KT 50 MPH 24H 08/0000Z 12.9N 105.3W 55 KT 65 MPH 36H 08/1200Z 13.9N 107.3W 70 KT 80 MPH 48H 09/0000Z 14.8N 109.0W 80 KT 90 MPH 60H 09/1200Z 15.7N 110.7W 90 KT 105 MPH 72H 10/0000Z 16.5N 112.3W 95 KT 110 MPH 96H 11/0000Z 18.1N 116.1W 85 KT 100 MPH 120H 12/0000Z 19.9N 121.6W 70 KT 80 MPH $$ Forecaster Stewart

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Tropical Depression Five-E Forecast Discussion Number 1

2020-07-06 22:38:29| National Hurricane Center (East Pacific)

Issued at 400 PM CDT Mon Jul 06 2020 208 WTPZ45 KNHC 062038 TCDEP5 Tropical Depression Five-E Discussion Number 1 NWS National Hurricane Center Miami FL EP052020 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 12H 07/0600Z 11.2N 101.1W 35 KT 40 MPH 24H 07/1800Z 12.1N 103.4W 45 KT 50 MPH 36H 08/0600Z 13.0N 105.5W 55 KT 65 MPH 48H 08/1800Z 14.1N 107.4W 65 KT 75 MPH 60H 09/0600Z 15.0N 109.0W 75 KT 85 MPH 72H 09/1800Z 15.7N 110.7W 85 KT 100 MPH 96H 10/1800Z 17.2N 114.1W 85 KT 100 MPH 120H 11/1800Z 18.8N 118.7W 70 KT 80 MPH $$ Forecaster Brown

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Post-Tropical Cyclone Edouard Forecast Discussion Number 10

2020-07-06 22:34:03| National Hurricane Center (Atlantic)

Issued at 500 PM AST Mon Jul 06 2020 000 WTNT45 KNHC 062033 TCDAT5 Post-Tropical Cyclone Edouard Discussion Number 10 NWS National Hurricane Center Miami FL AL052020 500 PM AST Mon Jul 06 2020 Although Edouard continues to produce some deep convection, recent satellite imagery and scatterometer data indicate that the center of the cyclone has merged with a frontal boundary. Therefore, the system is now classified as extratropical and this is the last advisory. The scatterometer data showed max winds of 35-40 kt, so the initial intensity remains 40 kt. The 35 kt wind radii were also increased in the southeast quadrant based on the scatterometer data. The post-tropical cyclone is forecast to continue moving quickly northeastward for the next day or so until it is absorbed into a larger frontal zone over the north Atlantic late Tuesday or early Wednesday. The NHC track and intensity forecast is close to the global model consensus, and all of those models are in good agreement for the next 24 h. This is the last NHC advisory on Edouard. Additional information on this system can be found in High Seas Forecasts issued by the National Weather Service, under AWIPS header NFDHSFAT1, WMO header FZNT01 KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php FORECAST POSITIONS AND MAX WINDS INIT 06/2100Z 42.7N 46.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 12H 07/0600Z 45.1N 40.7W 40 KT 45 MPH...POST-TROP/EXTRATROP 24H 07/1800Z 48.5N 33.2W 40 KT 45 MPH...POST-TROP/EXTRATROP 36H 08/0600Z...DISSIPATED $$ Forecaster Zelinsky

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Tropical Storm Edouard Forecast Discussion Number 9

2020-07-06 16:42:25| National Hurricane Center (Atlantic)

Issued at 1100 AM AST Mon Jul 06 2020 000 WTNT45 KNHC 061442 TCDAT5 Tropical Storm Edouard Discussion Number 9 NWS National Hurricane Center Miami FL AL052020 1100 AM AST Mon Jul 06 2020 Visible satellite imagery continues to show that the low-level center of Edouard is exposed to the southwest of the area of deep convection. A frontal boundary is approaching the system from the northwest and there are signs that Edouard's extratropical transition has begun. Subjective and objective intensity estimates from TAFB and UW/CIMSS are between 35-45 kt, and the initial intensity has been raised to 40 kt based on the above, and the rapid forward speed of the cyclone. ASCAT data should provide a better assessment of Edouard's intensity very shortly. Edouard is racing northeastward with an initial estimate of 055/32 kt. The cyclone should continue on this general speed and heading over the next day or two as it remains embedded within an area of strong southwesterly flow. The updated NHC track forecast is again near the middle of the guidance envelope and very similar to the previous advisory. Cooler waters, strong southwesterly vertical wind shear, and the approaching frontal zone should cause Edouard to complete its extratropical transition within the next 6-12 hours. Little change in strength is expected as this occurs. Gradual weakening should begin on Tuesday, and the post-tropical cyclone is forecast to dissipate within a frontal zone over the north Atlantic in a couple of days. FORECAST POSITIONS AND MAX WINDS INIT 06/1500Z 40.8N 50.0W 40 KT 45 MPH 12H 07/0000Z 43.2N 44.5W 40 KT 45 MPH...POST-TROP/EXTRATROP 24H 07/1200Z 46.7N 37.1W 40 KT 45 MPH...POST-TROP/EXTRATROP 36H 08/0000Z 50.0N 29.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 48H 08/1200Z 53.0N 20.0W 30 KT 35 MPH...POST-TROP/EXTRATROP 60H 09/0000Z...DISSIPATED $$ Forecaster Brown

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