#116 Postby oaba09 » Tue Nov 24, 2009 12:48 am
0300z prognostic reasoning from JTWC
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The models are still split however, it is important to take note that some models are predicting a western movement from Nida....IMO, the Philippines, Taiwan, and Japan needs to be prepared because of the uncertainty
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WDPN31 PGTW 240300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 26W (NIDA)
WARNING NR 09//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
A. TROPICAL STORM (TS) 26W (NIDA), LOCATED APPROXIMATELY 290 NM
SOUTH-SOUTHEAST OF GUAM, HAS TRACKED WESTWARD AT 08 KNOTS OVER THE
PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY INDICATES THAT TS
26W HAS CONTINUED TO CONSOLIDATE OVER THE PAST 12 HOURS AND HAS
DEVELOPED A CENTRAL DENSE OVERCAST. A 23/2139Z TRMM 37 GHZ IMAGE
DEPICTS IMPROVED ORGANIZATION WITH TIGHTLY-CURVED BANDING AND A
FORMATIVE MICROWAVE EYE FEATURE. THERE IS HIGH CONFIDENCE IN THE
CURRENT POSITION BASED ON THE MICROWAVE EYE SIGNATURE. THE CURRENT
INTENSITY OF 55 KNOTS IS ASSESSED SIGNIFICANTLY HIGHER THAN THE
DVORAK ESTIMATES OF 35-45 KNOTS FROM PGTW, KNES AND RJTD. THIS IS
BASED ON THE TIGHTLY-CURVED BANDING AND MICROWAVE EYE FEATURE.
ANIMATED WATER VAPOR IMAGERY INDICATES GOOD RADIAL OUTFLOW ENHANCED
BY AN UPPER-LOW NEAR 25N 165E.
3. FORECAST REASONING.
A. NO CHANGE IN FORECAST PHILOSOPHY ALTHOUGH TRACK SPEEDS HAVE
BEEN INCREASED AT THE LATER TAUS.
B. TS 26W IS CURRENTLY TRACKING UNDER THE STEERING INFLUENCE OF
THE MID-LEVEL SUBTROPICAL RIDGE POSITIONED NORTH OF THE SYSTEM. UPPER
AIR DATA FROM GUAM INDICATES DEEP EASTERLY FLOW UP TO 300 MB
SUPPORTING A STRONG EAST-WEST ORIENTED STR. THE JGSM TRACKER REMAINS
AN OBVIOUS OUTLIER WITH A NORTHWARD TRACK; THIS IS ASSESSED AS
ERRONEOUS BASED ON THE CURRENT ORIENTATION AND STRENGTH OF THE STR
TO THE NORTH. THE REMAINING GUIDANCE (ECMWF, GFDN, NOGAPS, UKMO,
TC-LAPS AND WBAR) IS IN TIGHT AGREEMENT THROUGH TAU 48 BUT QUICKLY
DIVERGE WITH TWO DISTINCT GROUPINGS. NOGAPS, GFDN, AND UKMO TRACK THE
SYSTEM WESTWARD AFTER TAU 72 WHILE ECMWF, TC-LAPS AND WBAR INDICATE
A MORE NORTHWESTWARD TRACK. THIS FORECAST IS CLOSE TO THE MODEL
CONSENSUS THROUGH TAU 72. TS 26W IS EXPECTED TO INTENSIFY AT A
10 KNOT PER DAY RATE.
C. IN THE EXTENDED TAUS, AS MENTIONED IN PARA 3.B., THERE IS
MORE UNCERTAINTY WITH TWO GROUPINGS OF MODEL TRACKERS. THIS
UNCERTAINTY IS THE RESULT OF THE MODEL'S DIFFERENT DEPICTION OF
THE STR AND MIDLATITUDE FLOW PATTERN SOUTH OF JAPAN. BASICALLY,
THE SYSTEM WILL EITHER STAIR-STEP OR RE-CURVE. IT IS A LITTLE EARLY
TO STATE WITH CONFIDENCE WHICH IS MORE LIKELY, HOWEVER, THE
RE-CURVE SCENARIO IS MORE LIKELY CLIMATOLOGICALLY AND IS SUPPORTED
BY THE LATEST ECMWF EXTENDED FIELDS WHICH MAINTAIN A WEAKNESS IN
THE STR AFTER TAU 72 AND TRACK THE SYSTEM POLEWARD. TS 26W SHOULD
CONTINUE TO INTENSIFY UNDER FAVORABLE CONDITIONS WITH ENHANCED
POLEWARD OUTFLOW INTO THE MIDLATITUDE WESTERLY FLOW.//
NNNN
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