TYPHOON NANGKA PUBLIC ADVISORY NUMBER 12
WIKI-HURRICANES FORECASTING CENTER
06:00 PM JST MON JUL 07 2015
...NANGKA RAPIDLY INTENSIFYING...NOW A TYPHOON....
SUMMARY OF 06:00 PM JST...09:00 UTC...INFORMATION
CENTER POSITION CONFIDENCE: VERY VERY VERY VERY VERY HIGH
ABOUT 340 MI...550 KM NE OF PALIKIR, MICRONESIA
MAXIMUM SUSTAINED WINDS...75 KT...85 MPH...135 KM/H
MINIMUM BAROMETRIC PRESSURE...969 MB...28.61 INCHES
PRESENT MOVEMENT...WNW AT 15 KT...16 MPH...25 KM/H
DISCUSSION AND 48-HOUR OUTLOOK
At 06:00 pm JST, the center of Typhoon Nangka was situated near 12.0N, 158.2E, or about 340 miles (550 kilometers) north-northeast of Palikir, Micronesia. Maximum sustained winds were 75 knots (85 mph, 135 km/h), with higher gusts. The minimum barometric pressure was 969 millibars (hPa; 28.61 inHg), and the cyclone was tracking west-northwest at 15 knots (16 mph, 25 km/h). Additional rapid intensification is expected as Nangka tracks west-northwestward.
Next complete advisory at 12:00 am JST.
TYPHOON NANGKA PUBLIC DISCUSSION NUMBER 12
WIKI-HURRICANES FORECASTING CENTER
06:00 PM JST SUN JUL 06 2015
And boom, here we have it. Go Nangka! It's bombing out. an eye has rapidly cleared over the last few hours, and microwave imagery shows a great structure with a well-organized inner core. At first, the eye was ragged, but since then cloud tops surrounding it have cooled, the eye has gotten to -8.2C (to OW status) and while have started to cool in the most recent frame, the eye is becoming more circular and less elongated and there overall appearance is somewhat less ragged than it was several hours ago. According to an 8z fix, DT=4.5.77 knts, though PT and MEy were at T4.0/65 knts. Typical with storms right at the start of the beloved RI phase, CIMSS ADT values have jumped as high as an NBA swingman and latest estimates as of this writing are at T5.0/90 knts, with adjusted values of T5.3/97 knts and raw values, using an eye pattern have yielded low 6's. Furthermore, estimates from JTWC are T4.0/65 knts. A blend of the above T-numbers mentioned would support around 80-85 knts, but keep in mind that the especially in non-pinhole storms, the satellite presentation is ahead of the wind speed. Therefore, the intensity is set at 75 knts.
Nangka is in the RI phase. Now the question is, how long will it last? Well, the answer is maybe not quite too longer. I will say this the ocean is not the problem. Sea surface temperatures, while below average due to a rapidly forming El Nino event, are expected to remain warm during the next five days, and oceanic heat content remains favorable, with maximum potential intensity values of around 140 knts. Maps from UW-CIMSS currently suggest that Nangka lies in 15kt shear and should shortly be entering some increasing wind shear, which may hamper intensification a bit, depending on how badly the low-level circulation separates from the main convective core. COAMPS indicates promptly decreasing shear, so which is riht and which is wrong. My hunch is that UW-CIMSS will be right; however, there are no signs of shear and thus it is safe to say that any increase in shear will likely be delayed. It is also possible that the shear is the result of Chan-hom's motion and thus a non-issue at this time. The intensity forecast brings this to 95 knts, before shear kicks in, slightly toying with its inner core briefly, and a CDO pattern could return for a short period of time in 12-24 hours. After that time, rapid deepening is likely to resume thereafter.
Nangka has sped up some towards the west-northwest, but generally speaking its motion is expected to be of moderate speed towards the west-northwest as it rounds the periphery of a 594dm subtropical high. After around two days Nangka is expected to take a course more northwesterly, but still towards the west-northwest, as an advancing trough creates a weakness and the ridge, pushing the ridge further east. This should bring Nangka near or even over the northern Mariana Islands in roughly three or four days. Afterwards, the advancing trough is expected to force Nangka in a different direction, most likely towards the north, though the specifics of this interaction is rather unclear at this time and diverges between the models. For the most part, the WHFC track remains largely the same and follows the general model consensus.
INIT 06/0900Z 120.0N 158.2E 75 KT 85 MPH
12H 06/1800Z 12.6N, 156.5W 95 KT 110 MPH
24H 07/0600Z 13.8N 154.5E 100 KT 115 MPH
36H 07/1800Z 14.9N 152.2E 110 KT 125 MPH
48H 08/0600Z 16.1N 150.1E 120 KT 140 MPH
72H 09/0600Z 17.8N 147.7W 130 KT 150 MPH ... NEAR NORTHERN MARIANA ISLANDS
96H 10/0600Z 20.6N 144.3E 130 KT 150 MPH ... NEAR NORTHERN MARIANA ISLANDS
120H 11/0000Z 23.2N 140.9E 130 KT 150 MPH