Typhoon Lupit 23:30Z 10.20.09
For a more recent update on the changing forecast track of Typhoon Lupit CLICK HERE
Typhoon Lupit Forecast Track
The Typhoon Lupit Forecast Track and intensity forecast remains fairly consistent. However, the timing of the landfall has been pushed back somewhat. The GFS model wants to take the storm into Luzon, south of Port San Vincente at 12Z Friday October 23. The US Navy NOGAPS model wants to run the storm between Bataan and Port San Vincente. The official track from the Joint Typhoon Warning Center splits this narrow difference in between. It appears to me that they both have a tropical cyclone making landfall with a central pressure of around 982 mb or so, which is relatively speaking, not that low. For that reason, the intensity forecast has been pulled back to about 90 kts (105 mph) at landfall. While the slower forward motion means the storm makes a landfall a day later than previously forecast, it also means that the storm will be affecting the northern Philippines for over 24 hours. The real problem with this storm will be the heavy rain potential. Areas on the mountains on the western half of the Luzon province will be particularly vulnerable.
Typhoon Lupit IR satellite loop-click more most recent loop
I’ve seen several different spellings for this storm. I’ve seen Typhoon Lupin, Typhoon Lupid, and Typhoon Renali. The last one is the name given in the western Pacific, which I can’t figure out because countries from all around the world contribute to the list of names used by the World Meteorological Organization, yet there is another list used by the locals. What is particularly perplexing about this is that Lupit was the name provided by the Phillipines. Anyway, in general, Typhoon Lupit has behaved itself and the forecast has been pretty verifiable. The track did move north of the 20 degree N. Latitude line before beginning to move more westward and so as the ridge builds in to the north and starts to shove the storm more west-southwesterly it is doing so a shade later. Hence, this is the reason for the forecast landfall point position just north of the previous landfall projections. By and large though, its not a significant shift except that the greatest storm surge, seas and even winds would remain just offshore if the forecast track is verified. But, its stilll several days away and so it would be wise for everyone on the northeastern part of Luzon to be prepared for the surge potential. I would also keep my ears on if I were in Taiwan. The fact that the storm has slowed down may allow for some other environmental factors that would cause the track to change significantly.
Total Precipitable Water Loop
The Total Precipitable Water loop is a good tool to view the motion of the storm. Clearly you can see the move to the northwest and then west. If you use the 20 degree N. Latititude line as a guide, it is also apparent that Typhoon Lupit has moved just south of due west in the latest images. It is also clearly apparent that drier air has surrounded the storm but in the later frames, the precipitable water reflectivity has increased. Hence, it is possible that the storm may be getting into a little better environment. This would not suggest that the storm will get stronger, but instead the degradation process is probably over. It still has a good looking structure and there is really nothing to suggest that this guy will just go away. If it does not stay over Luzon for long and follows the track that will keep at least part of the circulation over water means that the re-intensification process once it leaves the Philippines area may be more problematic for Vietnam. People forget that Vietnam was adversely affected by Ketsana and Parma. As it is, Vietnam or southern China will be affected by a significant tropical cyclone. But, its not totally out of the question that the storm may be stronger at its second landfall than the first.
Full Pacific Loop
Just as a sidelight, if you look at the full pacific satellite loop, you will notice another tropical cyclone south of Hawaii. That is Tropical Storm Neki. It is forecast to deepen into a Hurricane (or Typhoon though I think in the Central Pacific they are still Hurricanes) and move northwest. It is forecast to become pretty formidable and it will be interesting to see how it affects the Midway Islands.
WDPN31 PGTW 210300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 22W (LUPIT) WARNING NR 029//
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
A. TYPHOON (TY) 22W (LUPIT), LOCATED APPROXIMATELY 475 NM
NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-SOUTHWESTWARD AT
09 KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON
RECENT SATELLITE FIXES FROM PGTW AND RJTD AND EXTRAPOLATION FROM A
202310Z SSMIS MICROWAVE SATELLITE PASS. THE CURRENT INTENSITY
ESTIMATE OF 80 KNOTS IS CONSISTENT WITH A 202330Z PGTW DVORAK T-
NUMBER VALUE OF 4.0/5.0. TY 22W IS TRACKING WEST-SOUTHWESTWARD UNDER
THE STEERING INFLUENCE OF A SUBTROPICAL RIDGE EXTENSION TO THE
NORTH. THE INTERNAL STRUCTURE OF THE TYPHOON HAS NOT YET FULLY
RECOVERED AFTER CONTENDING WITH A SLOT OF DRIER, MORE STABLE AIR AND
UNDERGOING AN EYEWALL REPLACEMENT CYCLE. HOWEVER, A LARGE EYE
FEATURE, THOUGH OBSCURED IN MULTISPECTRAL SATELLITE IMAGERY, REMAINS
EVIDENT IN RECENT MICROWAVE SATELLITE IMAGERY INCLUDING THE 202310Z
3. FORECAST REASONING
A. FORECAST INTENSITIES HAVE BEEN DECREASED BASED ON THE CURRENT
WEAKENING TREND. HOWEVER, THE GENERAL FORECAST INTENSITY TREND AND
ASSOCIATED REASONING REMAINS UNCHANGED. FORECAST TRACK SPEEDS HAVE
ALSO DECREASED, PARTICULARLY IN THE EXTENDED PERIOD, IN ANTICIPATION
OF A WEAKER STEERING FLOW THAN PREVIOUSLY FORECAST.
B. TY 22W IS EXPECTED TO CONTINUE TRACKING GENERALLY WEST-
SOUTHWESTWARD THROUGH TAU 72 AS A SUBTROPICAL RIDGE ANALYZED TO THE
NORTH AND WEST OF THE TYPHOON REPLACES THE CURRENT SUBTROPICAL RIDGE
EXTENSION TO THE NORTH AS THE PRIMARY STEERING MECHANISM. THE TRACK
FORECAST FOR TY 22W HAS BECOME MORE UNCERTAIN SINCE THE PREVIOUS
PROGNOSTIC REASONING DUE TO A SPLIT IN THE NUMERICAL MODEL GUIDANCE.
ONE SET OF MODEL SOLUTIONS, INCLUDING THE NOGAPS, GFDN, AND GFS,
DEPICTS A SLOWDOWN AND POLEWARD RECURVATURE UNDER THE INFLUENCE OF A
STRENGTHENING PERIPHERAL ANTICYCLONE TO THE SOUTHEAST OF THE STORM
DURING THE NEXT 72 HOURS. A SECOND SET OF SOLUTIONS, INCLUDING THE
ECMWF, JGSM, AND UKMET, SHOW THE TYPHOON CONTINUING WESTWARD AS THE
SUBTROPICAL STEERING RIDGE TO THE NORTHWEST BECOMES THE PRIMARY
STEERING MECHANISM. THIS SECOND SET OF SOLUTIONS IS CONSISTENT WITH
THE MAJORITY OF THE PREVIOUS MODEL GUIDANCE AND JTWC FORECASTS, AND
IS SUPPORTED BY ANALYSIS OF BOTH A PERSISTENT SUBTROPICAL RIDGE TO
THE WEST-NORTHWEST OF TY 22W AND A ZONAL UPSTREAM MIDLATITUDE FLOW
PATTERN. THUS, THE CURRENT FORECAST TRACK FAVORS THESE WESTWARD-
RUNNING MODEL SOLUTIONS. HOWEVER, A SIGNIFICANT SHIFT IN THE
FORECAST MAY BE NECESSARY IF MODEL GUIDANCE AND SYNOPTIC FEATURES
SHIFT IN FAVOR OF THE SLOWER MOTION SCENARIO. LOW VERTICAL WIND
SHEAR AND FAVORABLE OCEAN HEAT CONTENT ARE EXPECTED TO SUPPORT SOME
INTENSIFICATION THROUGH TAU 48, WHEN THE STORM CIRCULATION WILL
BEGIN TO INTERACT WITH TERRAIN OVER NORTHERN LUZON.
C. TRACK SPEEDS ARE EXPECTED TO REMAIN RELATIVELY SLOW IN THE
TAU 96 TO TAU 120 EXTENDED FORECAST PERIOD AS WEAKNESS DEVELOPS IN
THE SUBTROPICAL STEERING RIDGE. AS THE WEAKENED CYCLONE REEMERGES
OVER WATER, FAVORABLY HIGH OCEAN HEAT CONTENT AND GOOD UPPER LEVEL
CONDITIONS SHOULD SUPPORT GRADUAL REINTENSIFICATION.//