WDPN32 PGTW 042100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (MARIA) WARNING
NR 09//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 10W (MARIA), LOCATED APPROXIMATELY 6 NM SOUTH
OF ANDERSEN AFB, HAS TRACKED NORTH-NORTHWESTWARD AT 09 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
DEPICTS A RAPIDLY CONSOLIDATING SYSTEM WITH AN OBLONG CENTRAL DENSE
OVERCAST FEATURE OBSCURING THE LOW-LEVEL CIRCULATION CENTER (LLCC).
HOWEVER, RECENT RADAR IMAGERY (LAST IMAGE RECEIVED AT 1728Z DUE TO
AN UNKNOWN OUTAGE AT THE RADAR SITE) FROM ANDERSEN AFB DEPICTED
TIGHTLY-CURVED BANDING WRAPPING INTO A WELL-DEFINED LLCC LOCATED
ABOUT 8NM TO THE SOUTHEAST OF ANDERSEN AFB. A 041808Z SSMIS 91GHZ
IMAGE REVEALS DEEP CONVECTIVE BANDING WRAPPING INTO A COMPACT CORE
WITH INTENSE DEEP CONVECTION OVER THE NORTH AND WEST QUADRANTS,
WHICH CORRESPONDS WELL TO THE AREA OF MAXIMUM WINDS OBSERVED IN THE
BASE VELOCITY PRODUCT. SURFACE OBSERVATIONS FROM ANDERSEN AFB SHOWED
THAT THE LLCC TRACKED JUST TO THE SOUTH OF THE BASE AND PRODUCED
MAXIMUM SUSTAINED WINDS AS HIGH AS 50 KNOTS WITH GUSTS AS HIGH AS 83
KNOTS--THESE WINDS HAVE QUICKLY ABATED AND NOW RANGE FROM 30 TO 35
KNOTS SUSTAINED. MINIMUM SLP WAS REPORTED AT 984MB, WHICH
CORRESPONDS TO A 50 TO 55 KNOT INTENSITY. THEREFORE, THE CURRENT
INTENSITY IS ASSESSED AT 55 KNOTS, HEDGED HIGHER THAN THE KNES/PGTW
DVORAK ESTIMATES OF T3.0 (45 KNOTS). OBJECTIVE DVORAK ESTIMATES
RANGE FROM 50 TO 55 KNOTS. UPPER-LEVEL ANALYSIS INDICATES A
FAVORABLE ENVIRONMENT WITH ROBUST POLEWARD OUTFLOW ENHANCED BY TUTT
CELLS NEAR 20N 160E AND 15N 135E. ADDITIONALLY, VERTICAL WIND SHEAR
(VWS) IS LOW, SST VALUES RANGE FROM 29 TO 30C AND OCEAN HEAT CONTENT
VALUES ARE VERY HIGH. TS 10W IS CURRENTLY LOCATED ALONG THE WESTERN
PERIPHERY OF A WEAK NORTH-SOUTH ORIENTED STEERING RIDGE WITH A
STRONG EAST-WEST ORIENTED SUBTROPICAL RIDGE (STR) ENTRENCHED TO THE
NORTH, THEREFORE, THE SYSTEM IS TRACKING NORTH-NORTHWESTWARD TO
NORTHWESTWARD.
3. FORECAST REASONING.
A. THE SYSTEM IS NOW FORECAST TO RAPIDLY INTENSIFY OVER THE NEXT
TWO TO THREE DAYS TO A PEAK INTENSITY OF 135 KNOTS BY TAU 72.
B. TS 10W IS FORECAST TO CONTINUE TRACKING NORTH-NORTHWESTWARD TO
NORTHWESTWARD THROUGH TAU 72. NUMERICAL MODEL GUIDANCE IS IN FAIR
AGREEMENT WITH A 170NM SPREAD IN SOLUTIONS AT TAU 72. THE SYSTEM IS
FORECAST TO RAPIDLY INTENSIFY THROUGH TAU 72 WITH A PEAK INTENSITY
OF 135 KNOTS AT TAU 72 DUE TO VERY FAVORABLE ENVIRONMENTAL
CONDITIONS.
C. AFTER TAU 72, TS 10W IS FORECAST TO TURN INCREASINGLY WEST-
NORTHWESTWARD AS THE EAST-WEST ORIENTED STR BECOMES THE DOMINANT
STEERING INFLUENCE. ENVIRONMENTAL CONDITIONS ARE FORECAST TO DEGRADE
AS SST COOLS SLIGHTLY, OCEAN HEAT CONTENT VALUES DECREASE AND UPPER-
LEVEL DIVERGENCE WEAKENS DUE TO INCREASING NORTHERLY VWS ASSOCIATED
WITH A BUILDING UPPER-LEVEL RIDGE TO THE NORTH AND NORTHWEST.
CONFIDENCE IN THE JTWC FORECAST TRACK REMAINS LOW DUE TO A FAIRLY
LARGE SPREAD OF 255NM IN SOLUTIONS AT TAU 120. THIS INCREASING
UNCERTAINTY BETWEEN THE MODELS IS LARGELY ATTRIBUTED TO SIGNIFICANT
DIFFERENCES IN THE STRENGTH OF THE STR.//
NNNN
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (MARIA) WARNING
NR 09//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 10W (MARIA), LOCATED APPROXIMATELY 6 NM SOUTH
OF ANDERSEN AFB, HAS TRACKED NORTH-NORTHWESTWARD AT 09 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
DEPICTS A RAPIDLY CONSOLIDATING SYSTEM WITH AN OBLONG CENTRAL DENSE
OVERCAST FEATURE OBSCURING THE LOW-LEVEL CIRCULATION CENTER (LLCC).
HOWEVER, RECENT RADAR IMAGERY (LAST IMAGE RECEIVED AT 1728Z DUE TO
AN UNKNOWN OUTAGE AT THE RADAR SITE) FROM ANDERSEN AFB DEPICTED
TIGHTLY-CURVED BANDING WRAPPING INTO A WELL-DEFINED LLCC LOCATED
ABOUT 8NM TO THE SOUTHEAST OF ANDERSEN AFB. A 041808Z SSMIS 91GHZ
IMAGE REVEALS DEEP CONVECTIVE BANDING WRAPPING INTO A COMPACT CORE
WITH INTENSE DEEP CONVECTION OVER THE NORTH AND WEST QUADRANTS,
WHICH CORRESPONDS WELL TO THE AREA OF MAXIMUM WINDS OBSERVED IN THE
BASE VELOCITY PRODUCT. SURFACE OBSERVATIONS FROM ANDERSEN AFB SHOWED
THAT THE LLCC TRACKED JUST TO THE SOUTH OF THE BASE AND PRODUCED
MAXIMUM SUSTAINED WINDS AS HIGH AS 50 KNOTS WITH GUSTS AS HIGH AS 83
KNOTS--THESE WINDS HAVE QUICKLY ABATED AND NOW RANGE FROM 30 TO 35
KNOTS SUSTAINED. MINIMUM SLP WAS REPORTED AT 984MB, WHICH
CORRESPONDS TO A 50 TO 55 KNOT INTENSITY. THEREFORE, THE CURRENT
INTENSITY IS ASSESSED AT 55 KNOTS, HEDGED HIGHER THAN THE KNES/PGTW
DVORAK ESTIMATES OF T3.0 (45 KNOTS). OBJECTIVE DVORAK ESTIMATES
RANGE FROM 50 TO 55 KNOTS. UPPER-LEVEL ANALYSIS INDICATES A
FAVORABLE ENVIRONMENT WITH ROBUST POLEWARD OUTFLOW ENHANCED BY TUTT
CELLS NEAR 20N 160E AND 15N 135E. ADDITIONALLY, VERTICAL WIND SHEAR
(VWS) IS LOW, SST VALUES RANGE FROM 29 TO 30C AND OCEAN HEAT CONTENT
VALUES ARE VERY HIGH. TS 10W IS CURRENTLY LOCATED ALONG THE WESTERN
PERIPHERY OF A WEAK NORTH-SOUTH ORIENTED STEERING RIDGE WITH A
STRONG EAST-WEST ORIENTED SUBTROPICAL RIDGE (STR) ENTRENCHED TO THE
NORTH, THEREFORE, THE SYSTEM IS TRACKING NORTH-NORTHWESTWARD TO
NORTHWESTWARD.
3. FORECAST REASONING.
A. THE SYSTEM IS NOW FORECAST TO RAPIDLY INTENSIFY OVER THE NEXT
TWO TO THREE DAYS TO A PEAK INTENSITY OF 135 KNOTS BY TAU 72.
B. TS 10W IS FORECAST TO CONTINUE TRACKING NORTH-NORTHWESTWARD TO
NORTHWESTWARD THROUGH TAU 72. NUMERICAL MODEL GUIDANCE IS IN FAIR
AGREEMENT WITH A 170NM SPREAD IN SOLUTIONS AT TAU 72. THE SYSTEM IS
FORECAST TO RAPIDLY INTENSIFY THROUGH TAU 72 WITH A PEAK INTENSITY
OF 135 KNOTS AT TAU 72 DUE TO VERY FAVORABLE ENVIRONMENTAL
CONDITIONS.
C. AFTER TAU 72, TS 10W IS FORECAST TO TURN INCREASINGLY WEST-
NORTHWESTWARD AS THE EAST-WEST ORIENTED STR BECOMES THE DOMINANT
STEERING INFLUENCE. ENVIRONMENTAL CONDITIONS ARE FORECAST TO DEGRADE
AS SST COOLS SLIGHTLY, OCEAN HEAT CONTENT VALUES DECREASE AND UPPER-
LEVEL DIVERGENCE WEAKENS DUE TO INCREASING NORTHERLY VWS ASSOCIATED
WITH A BUILDING UPPER-LEVEL RIDGE TO THE NORTH AND NORTHWEST.
CONFIDENCE IN THE JTWC FORECAST TRACK REMAINS LOW DUE TO A FAIRLY
LARGE SPREAD OF 255NM IN SOLUTIONS AT TAU 120. THIS INCREASING
UNCERTAINTY BETWEEN THE MODELS IS LARGELY ATTRIBUTED TO SIGNIFICANT
DIFFERENCES IN THE STRENGTH OF THE STR.//
NNNN
