Tropical Cyclone 03W Guchol / Tropical Cyclone 02A (Biparjoy) / Invest 99W
Saturday, June 10, 2023

Current Snapshot

For all the latest updates visit: DisasterAWARE

By PDC’s Senior Weather
Specialist Glenn James

Current Tropical Cyclones:

Tropical Cyclone 03W (Guchol)…is located approximately 286 NM southeast of Kadena AB

Tropical Cyclone 02A (Biparjoy)…is located approximately 415 NM south of Karachi, Pakistan


Northeast Pacific Ocean:

There are no tropical cyclones…nor any areas of disturbed weather under investigation by the National Hurricane Center (NHC)

Tropical cyclone formation is not expected during the next 7-days.


North Central Pacific Ocean:

There are no tropical cyclones…nor any areas of disturbed weather under investigation by the Central Pacific Hurricane Center (CPHC)

Tropical cyclone formation is not expected during the next 7-days.


Northwestern Pacific Ocean

Tropical Cyclone 03W (Guchol)

According to the JTWC Warning number 21, sustained winds are 85 knots…with gusts to near 105 knots

Animated enhanced infrared satellite imagery depicts a symmetric central dense overcast with a bulk of the convective banding limited to the south and east of the circulation. A microwave image reveals an open circulation in the upper levels due to dry air entrainment and persistent vertical wind shear, while the circulation is vertically tilted which will also serve to hinder its development.

With the loss of its eye feature, TY 03W (Guchol) is beginning to succumb to an increasingly hostile environment. Over the next 36 hours, 03W is forecast to gradually curve north-northeastward and eventually northeastward as the ridges to the east and south reorient and conjoin.

During this time, the tropical upper tropospheric trough (tutt), which had been fueling the systems upper level outflow fills in and moves northward. This reduced outflow coupled with cooling sea surface temperatures and relentless northerly shear will weaken the system to around 70 knots by 36 hours.

By 48 hours, 03W begins to interact with a passing shortwave trough, thereby commencing subtropical transition (stt).

Global models continue to indicate a rapid integration of the system within the passing trough, which will result in stt completing by 72 hours, and the initiation of extratropical transition (ett) by 96 hours. During this entire time, 03W will continue to weaken as it quickly moves poleward and is stripped of all remaining tropical characteristics.


Arabian Sea

Tropical Cyclone 02A (Biparjoy)

According to the JTWC Warning number 20, sustained winds are 100 knots…with gusts to near 125 knots

Animated multi-spectral satellite imagery depicts an increasingly exposed low level circulation which is the result of persistent and building upper level easterly shear. Tightly wrapping low level cloud lines can be seen in the eastern semicircle of the llcc providing some aid to localization. A recent microwave image indicates a convectively asymmetric circulation with a bulk of the deep convection limited to the southern semicircle.

TC 02A is forecast to remain on a generally northward trajectory through 72 hours, after which the bulk of the guidance indicates an eastward turn, while a few rebels still shift westward.

Currently in a marginal environment characterized by moderate upper level outflow and warm sea surface temperatures generally offset by persistent and building upper level wind shear. Through 24 hours, 02A may achieve limited growth but will likely simply stave off weakening if it can remain convectively cohesive.

After 24 hours however, persistent vertical wind shear now joined by rapidly deteriorating outflow aloft will gradually weaken the system through the remaining forecast period. The forecast track is another matter entirely. As the system progresses poleward, the cross-track spread and along-track spread in model solutions cannot be overstated.

Over the past few cycles, the run to run variability has improved but two distinct outcomes are still evident past 72 hours. The existence and strength of a ridge that sets up over the Gulf of Oman and the ridging over southern India are pivotal to the long term track direction of 02A.

The bulk of current deep layer mean model guidance favors the Gulf of Oman ridge and weaker ridging over southern India allowing the system to slip poleward and eastward.


Western Pacific Ocean

>>> There’s an area of disturbed weather being referred to as Invest 99W…which is located approximately 75.5 NM northwest of Haikou, Hainan Island

Animated multi-spectral satellite imagery, animated radar imagery and a microwave image depict a disorganized low level circulation center (llcc).

The environment is marginally favorable for development with robust equatorward outflow, low to moderate (15-20 knot) vertical wind shear, and very warm sea surface temperatures.

Interaction with land will hinder development, however global models are in agreement that Invest 99W will track southward or southeastward over the Gulf of Tonkin and slowly intensify over the next 24-48 hours.

Maximum sustained surface winds are estimated at 18 to 22 knots.

The potential for the development of a significant tropical cyclone within the next 24 hours remains low.