Jump to content
Holidays
Local
Radar
Snow?

Archived

This topic is now archived and is closed to further replies.

Somerset Squall

Tropical Storm Kirogi

Recommended Posts

TROPICAL DEPRESSION 13W (THIRTEEN) WARNING NR 001

02 ACTIVE TROPICAL CYCLONES IN NORTHWESTPAC

MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE

WIND RADII VALID OVER OPEN WATER ONLY

---

WARNING POSITION:

041800Z --- NEAR 23.8N 161.8E

MOVEMENT PAST SIX HOURS - 270 DEGREES AT 09 KTS

POSITION ACCURATE TO WITHIN 020 NM

POSITION BASED ON CENTER LOCATED BY SATELLITE

PRESENT WIND DISTRIBUTION:

MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT

WIND RADII VALID OVER OPEN WATER ONLY

REPEAT POSIT: 23.8N 161.8E

---

FORECASTS:

12 HRS, VALID AT:

050600Z --- 24.4N 161.3E

MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT

WIND RADII VALID OVER OPEN WATER ONLY

VECTOR TO 24 HR POSIT: 360 DEG/ 07 KTS

---

24 HRS, VALID AT:

051800Z --- 25.8N 161.3E

MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT

WIND RADII VALID OVER OPEN WATER ONLY

VECTOR TO 36 HR POSIT: 010 DEG/ 08 KTS

---

36 HRS, VALID AT:

060600Z --- 27.4N 161.6E

MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT

WIND RADII VALID OVER OPEN WATER ONLY

RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT

040 NM SOUTHEAST QUADRANT

035 NM SOUTHWEST QUADRANT

040 NM NORTHWEST QUADRANT

VECTOR TO 48 HR POSIT: 005 DEG/ 07 KTS

---

EXTENDED OUTLOOK:

48 HRS, VALID AT:

061800Z --- 28.8N 161.8E

MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT

WIND RADII VALID OVER OPEN WATER ONLY

RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT

040 NM SOUTHEAST QUADRANT

040 NM SOUTHWEST QUADRANT

040 NM NORTHWEST QUADRANT

VECTOR TO 72 HR POSIT: 355 DEG/ 05 KTS

---

72 HRS, VALID AT:

071800Z --- 30.8N 161.5E

MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT

WIND RADII VALID OVER OPEN WATER ONLY

RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT

065 NM SOUTHEAST QUADRANT

060 NM SOUTHWEST QUADRANT

060 NM NORTHWEST QUADRANT

VECTOR TO 96 HR POSIT: 330 DEG/ 07 KTS

---

LONG RANGE OUTLOOK:

---

96 HRS, VALID AT:

081800Z --- 33.1N 160.0E

MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT

WIND RADII VALID OVER OPEN WATER ONLY

BECOMING EXTRATROPICAL

VECTOR TO 120 HR POSIT: 325 DEG/ 10 KTS

---

120 HRS, VALID AT:

091800Z --- 36.3N 157.4E

MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT

WIND RADII VALID OVER OPEN WATER ONLY

BECOMING EXTRATROPICAL

---

TROPICAL DEPRESSION 13W (THIRTEEN), LOCATED APPROXIMATELY 385 NM

NORTHWEST OF WAKE ISLAND, HAS TRACKED WESTWARD AT 09 KNOTS OVER THE

PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS

CENTRAL CONVECTION HAS BEEN STEADILY DEVELOPING OVER A WELL

ORGANIZED LOW LEVEL CIRCULATION CENTER (LLCC) FOR THE PAST SIX

HOURS. THE CURRENT INTENSITY OF 25 KNOTS IS BASED ON DVORAK

ESTIMATES FROM PGTW AND RJTD AND IS SUPPORTED BY A RECENT OSCAT PASS

SHOWING BETWEEN 25 TO 30 KNOTS NEAR THE CENTER OF THE LLCC. OVER THE

PAST SIX HOURS THE TRACK OF THE LLCC HAS TURNED TO THE WEST AND

INCREASED SPEED. PRIOR TO THIS THE TRACK HAS BEEN SLOWLY TRACKING

EASTWARD IN A WEAK STEERING ENVIRONMENT. UPPER LEVEL ANALYSIS

INDICATES A STRONG POLEWARD OUTFLOW CHANNEL IS BEING SUPPORTED BY A

TROPICAL UPPER TROPOSPHERIC TROUGH CELL LOCATED TO THE EAST OF THE

LLCC. ADDITIONALLY, ANIMATED WATER VAPOR IMAGERY AND TOTAL

PRECIPITABLE WATER SHOWS A DRY RIBBON IS BUILDING ALONG THE WESTERN

PERIPHERY AROUND THE SOUTHERN PERIPHERY, EXTENDING TO THE

NORTHEASTERN QUADRANT. THIS DRY AIR HAS ALMOST FULLY ENCOMPASSED THE

SYSTEM. VERTICAL WIND SHEAR (VWS) OVER THE AREA IS LOW (05 TO 10

KNOTS). SEA SURFACE TEMPERATURES (SSTS) ARE FAVORABLE (28 TO 29

CELSIUS) ALLOWING CONTINUED DEVELOPMENT.

3. FORECAST REASONING.

A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE FORECAST

PHILOSOPHY.

B. TD 13W IS FORECAST TO TURN NORTHWARD AS A DIGGING TROUGH

LOCATED TO THE NORTH WEAKENS THE SUBTROPICAL RIDGE (STR) LOCATED TO

THE NORTHEAST OF TD 13W. A BUILDING NEAR EQUATORIAL RIDGE (NER) TO

THE SOUTHEAST OF TD 13W IS EXPECTED TO BUILD HELPING TO TRACK THE

SYSTEM TO THE NORTH THROUGH TAU 72. MARGINAL UPPER LEVEL ENVIRONMENT

AND SLOWLY DECREASING SSTS WILL KEEP TD 13W FROM DEVELOPING

SIGNIFICANTLY OVER THE NEXT 72 HOURS. THERE IS LOW CONFIDENCE IN THE

CURRENT TRACK FORECAST AS THIS IS THE INITIAL FORECAST.

C. BEYOND TAU 72, DECREASING SSTS AND THE APPROACH OF A SECONDARY

TROUGH IN THE MID-LATITUDES WILL BEGIN TO ABSORB TD 13W, AND WILL

ALSO MODIFY THE STR, WHICH BECOMES THE DOMINANT STEERING MECHANISM

AFTER TAU 72, INTO A MORE NORTHWEST-SOUTHEAST ORIENTATION. THIS

ORIENTATION WILL CAUSE TD 13W TO TRACK NORTHWESTWARD TOWARDS THE

TROUGH. EXTRATROPICAL TRANSITION IS EXPECTED TO BEGIN AROUND TAU 96.

DUE TO THE HIGH LEVEL OF UNCERTAINTY WITHIN THE TRACK AND INTENSITY

FORECAST, CONFIDENCE IS LOW.//

NNNN

Share this post


Link to post
Share on other sites

13W now has an intensity of 35kts. Located well out to sea (163 degrees E), 13W shouldn't threaten land. 13W is currently heading northwards in an area of low shear and warm sea temps. This environment should allow some modest intensification. Ridging is expected to build to the north of 13W forcing the cyclone westwards in a couple days time. At this time, shear is expected to rise. The current northward motion will also take 13W over cooler waters. These two factors should produce weakening after 48hrs, and dissipation is expected over water.

wp132012.12080512.gif

Share this post


Link to post
Share on other sites

13W has strengthened to 45kts. Interesting to note that JMA have ceased advisories on the system and JTWC are monitoring it as a tropical storm. The effects of cooler sea temps are already becoming apparent as the convection is becoming increasingly shallow about the LLC. With cooling sea temps and higher shear awaiting 13W to the northwest, weakening will begin soon.

Share this post


Link to post
Share on other sites

13W has weakened to 35kts. Very little convection remains near the well defined LLC. This is in part due to increasingly cool sea temps as the storm continues to head towards the north-northwest. With increasing shear forecast, 13W is not long for this world.

Share this post


Link to post
Share on other sites

JMA have finally upgraded 13W to a tropical storm named Kirogi (better late than never IMO). The storm has intensified a little to 40kts this morning. Convection is shallow about the LLC but remains persistant. For the reasons described above however, Kirogi should start to weaken again soon.

Share this post


Link to post
Share on other sites
post-6667-0-80502800-1344411809_thumb.jp

Share this post


Link to post
Share on other sites

Kirogi is hanging on in there as it moves north-northwestwards towards eastern Japan. Intensity is down to 35kts again. The storm retains a well defined LLC with minimal shower activity due to cool sea temps. Shear is fairly low which is allowing the storm to persist. JTWC forecast transition into a subtropical storm as it closes in on eastern Japan. The storm is expected to remain fairly weak through this transition so weather impacts to eastern Japan should be minimal.

Share this post


Link to post
Share on other sites

  • Recently Browsing   0 members

    No registered users viewing this page.

×