Daily weather brief – Thursday, December 22, 2016

NORTH

New surge of Siberian air is pushing through the north region today, with the coldest air staying in the northernmost reaches of the region. A storm system associated with the surge front will bring a chance of rain to the Korean peninsula and japan, while moderate snowfall will affect southeastern Russia and extreme northeastern China. Clouds and a few sprinkles will also linger over eastern China as the frontal system continues to push offshore. Behind the front, temperatures are well below freezing to the north, and near single digits C (30s-low 40’s F) across the majority of the region.

CENTRAL

The latest frontal system is pushing offshore of the central region today, helping generate clouds and showers over much of the region and ushering in a refreshing shot of cooler air, in advance of a much stronger surge early next week. The front will bring rainfall to the Ryukyu Islands and Taiwan, and also kick up some showers in southern China and northern Indochina, as clouds linger over the higher terrain of south-central China. Temperatures are falling slightly over the region, with the greatest effect felt in the more southerly locations.

SOUTH

Attention in the south region remains fixed on what will be a Christmas Grinch of a storms system, in the form of tropical storm 30W. This system is expected to cross the Philippines during, or just after, Christmas day. For more on this system, please see the “tropics’ section of this briefing. For today, most locations will see drier air with partly cloudy to sunny conditions. Some thunderstorms could pop up in the more southerly locales of the southern Philippines, Singapore, and the Malay Peninsula as tropical moisture stays locked in. Temperatures will stay warm across the region, with all points checking in with highs in the low-30’sC (near 90F).

TROPICS

30W upgraded to tropical storm and given the name “NOCK-TEN”…forecasts show southern Luzon landfall on late evening on Christmas…

30W has been upgraded to a TROPICAL STORM and given the international name NOCK-TEN. At 5am, J.T.W.C placed the center near 7.9N, 140.3E, or about 1863km (1158mi) southeast of Virac, Catanduanes, Philippines. The system is moving west-northwest at 12 knots (22kph). Latest official forecast tracks bring the system into southern Luzon very late on Christmas day however; strength estimates on landfall differ between J.T.W.C. and J.M.A. The system is currently affecting the western islands of Micronesia as it presses on its course, with Yap Island seeing the greatest effects today.

J.T.W.C. is showing a system with 95kt (176kph) sustained winds, a “very strong typhoon” on the J.M.A. scale, or, a strong CAT 2 equivalent typhoon on the Saffir-Simpson scale, while J.M.A. is indicating a much weaker system at only 50kt (93kph) sustained winds, a tropical storm equivalent on the Saffir-Simpson scale, or, a “severe tropical storm” on the J.M.A. strength scale.. This difference is due to the changing atmospheric profiles and the disparity between computer-generated forecast models.

30W-GRADIENT WINDS-22 DEC

It should be noted, and not trivially, that where you are in relation to this system when/if it makes landfall will determine how strong the winds are at your location.

Due to the established strong northeast monsoon, or “amihan”, locations to the north of the system’s center of circulation will see stronger winds than locations to the south.

First, we have what is called the “pressure gradient”, or, the short distance between to areas of greatly different atmospheric pressure. The closer these areas are to each other, the higher the winds will be due to the very rapid differences in pressure. Think of high pressure as a dome and low pressure as a vortex…air will travel from the top of the dome to the center of the vortex more rapidly if their relative distance is shorter.

Secondly, we have the storm’s forward speed, which adds to the factor.

Finally, we have the NE monsoon, or “amihan”, which we have estimated near 20kt.

The effects are cumulative. For the sake of this instruction, we have split the difference between the current strength estimates given by JMA and JTWC, and settled on a 75kt (139kph) storm system, and found a median track forecast placement as well.

Here is how the math works:

Storm’s winds – 75kt (139kph)

Storm’s forward speed – 12kt (20kph)

NE monsoon winds – 20kt (37kph

Total cumulative winds north of center – 107kt (198kph). Here’s a graphic to demonstrate:

Winds could be up to 40-50kph stronger, or more, in locations immediately north of the center. The storm will also enhance the “amihan”, meaning a much more extensive wind field in the northern half, and specifically in the northwestern quadrant, of the system. This wind field will extend a great distance to the north.

Conversely, if you are located to the south of the system, winds will be strong, but not as strong as the northwestern portion of the system.

Residents of the eastern Philippines, from the northern Visayas to central Luzon, should have begun initial preparations for a significant weather system. This means stocking up on water and non-perishable foods, LPG for cooking, and planning an evacuation route if you feel it may be necessary. Better preparation is the key, and with the holiday approaching, one may tend to be lax or even discount the threat.

The remainder of the tropics region will see plentiful moisture in place combining with the warm afternoon sunshine to generate scattered showers and thunderstorms, with the more northerly locales being the lone exceptions.

Have a thrilling Thursday!

Courtesy: CIMSS, Tropical Tidbits, JMA, JTWC, Intellicast, WUnderground.com, N.R.L., RAMMB-NOAA

==================================================================

Disclaimer:

By making use of any information on this website, you agree to the following:

NO WARRANTIES: All of the information provided on this website is provided “AS-IS” and with NO WARRANTIES. No express or implied warranties of any type are made with respect to the information, or any use of the information, on this site. Westernpacificweather.com makes no representations and extends no warranties of any type as to the accuracy or completeness of any information or content on this website.

DISCLAIMER OF LIABILITY: Westernpacificweather.com specifically DISCLAIMS LIABILITY FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES and assumes no responsibility or liability for any loss or damage suffered by any person as a result of the use or misuse of any of the information or content on this website. Westernpacificweather.com assumes or undertakes NO LIABILITY for any loss or damage suffered as a result of the use, misuse or reliance on the information and content on this website.

USE AT YOUR OWN RISK: This website is for informational purposes only. The opinions expressed within this website are the opinions of each contributor. Westernpacificweather.com urges you to consult with OFFICIAL sources for information whenever you feel a threat is impending.

All rights reserved. © 2016 Westernpacificweather.com