Archive | April, 2014

Where in the world is Peipah? (Wednesday morning)

Wanted to share a quick graphic with you that shows the large variance between meteorological agencies on determining the center of Tropical Storm Peipah.  This is the analysis–not a forecast–by trained meteorologists.  As you can see, there are differences as great as about 160 km (between JMA and JTWC).  That is the difference between Tacloban City and Cebu City!  I share this image to emphasis how this science can sometimes be an art.  Of course, with each analyzed circulation, this creates shifts in the forecast track.  If the track starts off 150 km too far north… this can lead to similar, if not greater, errors over time in the forecast.


Tropical Storm Peipah (Bagyo Domeng) Update #10 — Tuesday Night

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Tropical Storm Peipah remains on that thin line between re-intensification and becoming a weak tropical depression.  After analyzing the 12Z (8pm Philippine Time) data, nearly all the satellite-derived data suggests that Peipah should be downgraded to a tropical depression, much like PAGASA and JTWC did.  However, JMA continues report Peipah as a weak tropical storm with sustained winds of 65 km/h.


The near-term forecast challenge will be the forward progress on Peipah toward a weakness in the subtropical ridge.  With the weak steering current, Peipah could slow down or become nearly stationary over the next few days before the subtropical ridge builds back in and accelerates Peipah toward the northwest.  Another challenge are some weak low-level vortices found on microwave imagery that may be disturbing the low-level development and may be responsible for the apparent northward acceleration over the past 6-12 hours.

All in all, Peipah remains a threat for heavy rainfall, flooding, and possible mudslides, especially for Samar and Bicol later in the week.  Of course, if Peipah slows down and/or the center redevelops, the track can easily change.  Therefore, the Philippines as a whole should continue to monitor the progress of this system.

Please continue to check in with us here at for more information.

Tropical Storm Peipah (Domeng) Update #7 | Monday Morning

Tropical Storm Peipah (Bagyong Domeng) continues to struggle amidst the moderate wind shear in the region. The system is now leaving the Republic of Palau and moving towards the Philippines. The center was last located approximately 120km west southwest of Koror, Palau or about 870km east of Davao City. Maximum sustained winds remain at 65kph with gusts of up to 93kph according to Japan Meteorological Agency. Peipah is moving westward at 20kph.

IR Image from NRLMRY

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Latest satellite image shows how poorly organized Peipha is currently. The convection continues to get sheared to the west and the low-level circulation center is almost fully exposed this morning. In fact, the Joint Typhoon Warning Center has downgraded Peipha to a Tropical Depression on their latest warning. Due to the atmospheric conditions in the region, Peipah will likely struggle to intensify in the coming days and may not even become a Typhoon anymore.

Rainfall Forecast from COAMPS

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Tropical Storm Peipah brought over 150mm of rainfall across Palau yesterday. We expect this similar amount, if not more, to fall across the Southern Philippines in the next three days. Light rains may actually start impacting Mindanao tonight and into tomorrow as the system moves from the east. Aside from the rains, the threat of storm surge and strong winds should also be kept in mind especially for residents living along the eastern coastline.

We’ll continue to post updates on this system so stay with Western Pacific Weather. As always, follow your official agency’s forecast (PAGASA) for the latest warnings on this storm.