Typhoon Lupit Forecast Track Highly Uncertain; Philippine Flooding Threat Remains

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Typhoon Lupit Forecast Track

Within the previous post, I made the following comment regarding the Typhoon Lupit Forecast Track: “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.”  What I was talking about is that the forecast track that has been so consistent for so long with a landfall for the northern Philippines was based on the assumption of the storm maintaining a consistent forward motion.  I had noted that Typhoon Lupit was slowing down.  The problem with that is that as it slows down, it allows for the increasing potential that the steering mechanisms will change.  That appears to have happened.  The models,which had been tightly packed are now all over the place.  It is no longer a probability that Typhoon Lupit strikes the Philippines but instead just one of a number of possibilities.  There is even the real possibility that this storm hits nothing; that is curves north of the Philippines, stays east of Taiwan and gets picked up in the flow such that it races northeast off the Japan coast.  But again, that is but one possibility. 

Typhoon Lupit Water Vapor Loop

As it stands now, the official track takes Typhoon Lupit just along the northern coast of Luzon at a very slow pace if not nearly stationary.  That would be potentially very bad as the center of circulation would stay offshore and heavy rain potential for over 48 hours over Luzon could be extremely problematic.  I would almost venture to say that this is a worse scenario than a direct quick hit and passage.  But, if you read the forecast reasoning from the Joint Typhoon Warning Center below, you can read the number of times that they speak of uncertainty.  The reason for that is that, as previously stated, the models are all over the place.  There are indications that the steering ridge to the west over China is eroding.  That would tend to support the models contention that the ridge over the Pacific will become more dominant with its influence.  Think of it as a weakness between ridges and if that is the case, then the storm will want to go poleward between the ridges in that  weak channel.  But, the potential problem lies in the time it takes for that weak channel to develop.  Until it does, the storm will sorta drift around in a quasistationary state until the steering currents get more established.  That is what the early morning forecast track on October 22 reflects. 

Total Precipitable Water Loop

This is no longer a forecast of high confidence.  The Philippines is still not out of the woods.  But, Taiwan and Japan face a possible threat.  I had noted that there seemed to be some dry air within the storm that may inhibit intensification.  The JTWC, however, notes dry air to the northwest but reports that the Total Precipitable Water imagery does not indicate that dry air has gotten into the flow. If the storm does in fact have enough momentum to take it down toward the Philippines before it begins to drift, the JTWC feels like there is some chance for an increase in intensity but it is almost unthinkable for this to get anywhere close to its former super typhoon status.  I would think that the biggest concern for Luzon will be rainfall and the proximity of the storm to the coast when it does become quasistationary.  If this guy lingers around too long, it may get killed by some unforseen outside influence.  So many possibilities and so many questions.

 

WDPN31 PGTW 220300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 22W (LUPIT) WARNING NR 033//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
    A. TYPHOON 22W (LUPIT), LOCATED APPROXIMATELY 340 NM NORTHEAST
OF MANILA, PHILIPPINES, HAS TRACKED WEST-SOUTHWESTWARD AT 05 KNOTS
OVER THE PAST SIX HOURS. RECENT ANIMATED MULTISPECTRAL IMAGERY SHOWS
A SYSTEM WITH GOOD RADIAL OUTFLOW AND DEEP CONVECTIVE BANDS WRAPPING
TIGHTLY INTO A LOW LEVEL CIRCULATION CENTER (LLCC). THE SYSTEM
REMAINS IN A WEAK STEERING ENVIRONMENT, TRANSITIONING BETWEEN THE
SUBTROPICAL RIDGE (STR) TO THE EAST AND THE STR TO THE WEST.
ENVIRONMENTAL ANALYSIS SHOWS THE SYSTEM UNDER AN UPPER-LEVEL
ANTICYCLONE IN A REGION OF FAVORABLE SEA SURFACE TEMPERATURES AND
LOW VERTICAL WIND SHEAR. WATER VAPOR IMAGERY SHOWS THE SYSTEM HAS
SIGNIFICANT DRY AIR TO THE NORTHWEST OF THE SYSTEM, BUT PRECIPITABLE
WATER DOES NOT YET SHOW DRY AIR INTRUSION. POSITION IS BASED ON
FIXES FROM PGTW AND RJTD. INTENSITY IS BASED ON ESTIMATES FROM PGTW,
RJTD AND KNES.
3. FORECAST REASONING
    A. THIS FORECAST REPRESENTS A SIGNIFICANT CHANGE IN THE FORECAST
PHILOSOPHY SINCE THE LAST PROGNOSTIC REASONING BULLETIN. THE CURRENT
FORECAST HAS THE SYSTEM BECOMING QUASISTATIONARY IN THE VICINITY OF
THE STRAIT OF LUZON WITH THE VERY PROBABLE SCENARIO OF A POLEWARD
TURN.
    B. TY 22W IS EXPECTED TO SLOW AND LOITER IN THE WEAK STEERING
ENVIRONMENT BETWEEN THE STR TO THE EAST AND THE STR TO THE WEST. THE
SYSTEM IS EXPECTED TO SLOWLY INTENSIFY IN A RELATIVELY FAVORABLE
ENVIRONMENT AS IT APPROACHES THE NORTHERN TIP OF LUZON. THE FURTHER
WEST THE SYSTEM TRACKS, THE LESS OF AN INFLUENCE THE STR TO THE WEST
BECOMES. THE WESTERN RIDGE, HOWEVER, IS BEING ERODED BY DRY,
NORTHWESTERLY FLOW AND IS NOT EXPECTED TO BECOME A DOMINANT
INFLUENCE ON THE SYSTEM IN THE EARLY TAUS. NUMERICAL MODEL GUIDANCE
REMAINS ERRATIC, A COMMON INDICATOR OF A WEAK STEERING ENVIRONMENT.
UNTIL THEY STABILIZE, NOT A LOT OF CREDIBILITY IS BEING PLACED ON
THE MODELS. CURRENTLY, THE MAJORITY OF AIDS HAVE THE SYSTEM MAKING A
SUDDEN POLEWARD TURN BETWEEN TAUS 12 AND 24; PRESUMABLY THEY HAVE
THE STR TO THE EAST BECOMING THE MAIN INFLUENCE ON THE SYSTEM.
CURRENT ENVIRONMENTAL ANALYSIS OF THE REGION DOES NOT REVEAL A CLEAR
PICTURE OF THE SYNOPTIC STEERING FLOW, LIKELY DUE TO THE WEAK
ENVIRONMENT. THIS FORECAST PRESENTS THE SYSTEM TRACKING VERY SLOWLY
IN THE ILL DEFINED STEERING FLOW.
   C. AS THE SYSTEM APPROACHES THE NORTHERN TIP OF LUZON, IT IS
EXPECTED TO START WEAKENING SLIGHTLY AS INFLOW BECOMES DISRUPTED.
THE SYSTEM WILL CONTINUE TO TRACK SLOWLY, AND SHOULD SEE A SLIGHT
POLEWARD TURN DURING THE PASSAGE OF A SHORT-WAVE MIDLATITUDE TROUGH.
THERE REMAINS A VERY LIKELY CHANCE THAT THE SYSTEM WILL BE PICKED UP
BY THE WESTERN PERIPHERY OF THE STR TO THE EAST SOMETIME BETWEEN TAU
12 AND TAU 36, IN WHICH CASE IT WILL TURN POLEWARD AND START TO
ACCELERATE INTO THE MIDLATITUDE WESTERLIES. //
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