WTPA34 PHFO 120240
TCPCP4

BULLETIN
TROPICAL STORM NORA ADVISORY NUMBER 11
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP182015
500 PM HST SUN OCT 11 2015

…NORA CONTINUES MOVING WEST NORTHWESTWARD FAR SOUTHEAST OF
HAWAII…

SUMMARY OF 500 PM HST…0300 UTC…INFORMATION
———————————————-
LOCATION…13.5N 143.8W
ABOUT 860 MI…1385 KM ESE OF HILO HAWAII
MAXIMUM SUSTAINED WINDS…70 MPH…110 KM/H
PRESENT MOVEMENT…WNW OR 300 DEGREES AT 9 MPH…15 KM/H
MINIMUM CENTRAL PRESSURE…993 MB…29.33 INCHES

WATCHES AND WARNINGS
——————–
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

DISCUSSION AND 48-HOUR OUTLOOK
——————————
AT 500 PM HST…0300 UTC…THE CENTER OF TROPICAL STORM NORA WAS
LOCATED NEAR LATITUDE 13.5 NORTH…LONGITUDE 143.8 WEST. NORA IS
MOVING TOWARD THE WEST-NORTHWEST NEAR 9 MPH…15 KM/H. NORA WILL
GRADUALLY SLOW DOWN THROUGH MONDAY…WITH A TURN TOWARD THE
NORTHWEST FORECAST BY LATE MONDAY THROUGH TUESDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 70 MPH…110 KM/H…WITH HIGHER
GUSTS. NORA WILL STRENGTHEN A BIT THROUGH TONIGHT…BRIEFLY
BECOMING A HURRICANE…THEN BEGIN TO WEAKEN MONDAY AND TUESDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 70 MILES…110 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 993 MB…29.33 INCHES.

HAZARDS AFFECTING LAND
———————-
NONE

NEXT ADVISORY
————-
NEXT COMPLETE ADVISORY…1100 PM HST.

$$
FORECASTER POWELL
WTPA44 PHFO 120240
TCDCP4

TROPICAL STORM NORA DISCUSSION NUMBER 11
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP182015
500 PM HST SUN OCT 11 2015

NORA IS A COMPACT TROPICAL SYSTEM…AND THE CENTRAL DENSE OVERCAST
AREA HAS BECOME SMALLER THIS AFTERNOON. LOW CLOUD LINES APPEAR TO
PLACE THE LOW LEVEL CIRCULATION CENTER…LLCC…BENEATH THE EASTERN
EDGE OF DEEPEST CONVECTION. A 2339 UTC SSMI MICROWAVE PASS…WHILE
NOT CONCLUSIVE…MARGINALLY SUPPORTS THE INITIAL POSITION…BUT
CONFIDENCE IS NOT VERY HIGH WITHOUT AN INFRARED WARM SPOT OR A
VISIBLE EYE. THIS SAME SSMI PASS SHOWED A LACK OF AN EYEWALL ACROSS
THE EASTERN SEMICIRCLE. SUBJECTIVE DVORAK SATELLITE INTENSITY
ESTIMATES RANGED FROM 3.5…55 KT…FROM JTWC TO 4.0…65 KT…FROM
PHFO AND SAB. UW-CIMSS ADT REMAINED 3.9…63 KT. NORA LOOKS NO
BETTER ORGANIZED THAN IT DID THIS MORNING AND…WITH NO
COMPLETE EYEWALL DEPICTED IN MICROWAVE IMAGERY…WE WILL HOLD THE
INITIAL INTENSITY AT 60 KT FOR THIS ADVISORY.

ANIMATION AND SUCCESSIVE SSMI PASSES SEEM TO SHOW THAT NORA IS
MAINTAINING A MORE NORTHERLY TRACK THIS AFTERNOON THAN IT WAS
OVERNIGHT. INITIAL MOTION IS SET AT 300/08 KT…NOTICEABLY SLOWER
THAN BEFORE. TRACK GUIDANCE CONTINUES TO DEPICT NORA MOVING
WEST NORTHWESTWARD THROUGH 36 HOURS…ALONG THE SOUTHWEST FLANK OF
MID-LEVEL RIDGING TO THE NORTHEAST OF THIS SYSTEM. GUIDANCE THEN
RECURVES NORA NORTHWARD ON DAYS TWO AND THREE…THEN NORTHEASTWARD
ON DAYS FOUR AND FIVE AS A DEEP TROUGH NORTH OF HAWAII MOVES
EAST…WEAKENS THE RIDGE…AND SCOOPS NORA OUT OF THE DEEP TROPICS.
THE SPREAD IN TRACK GUIDANCE IS DUE TO DIFFERENCES IN INITIAL
MOTION AND FORWARD SPEED DURING RECURVATURE. IN SPITE OF THIS
UNCERTAINTY…ALL OF THE GUIDANCE EITHER RECURVES NORA NORTHEASTWARD
FAR FROM HAWAII…OR DECAPITATES NORA AND SHOVES THE REMNANTS WEST
SOUTHWESTWARD WITHIN THE TRADES.

INTENSITY GUIDANCE SHOWS THE WINDOW FOR STRENGTHENING WILL LIKELY
SLAM SHUT IN 12 HOURS. SHEAR ACROSS NORA HAS INCREASED INTO THE 15
TO 20 KT RANGE THIS AFTERNOON BUT…WITH SEA SURFACE TEMPERATURES
NEAR 29C…SHIPS AND LGEM ALLOW FOR A SMALL INTENSITY INCREASE
THROUGH TONIGHT. GUIDANCE THEN AGREES ON STEADY WEAKENING THROUGH
120 HOURS…WITH SHIPS DISSIPATING NORA AT 96 HOURS. WE WILL
CONTINUE TO PEAK NORA AT 65 KT…AS A HURRICANE…IN 12 HOURS.
HOWEVER…WE NOW FORECAST CONTINUED WEAKENING THEREAFTER.
FORECAST POSITIONS AND MAX WINDS

INIT 12/0300Z 13.5N 143.8W 60 KT 70 MPH
12H 12/1200Z 14.0N 144.9W 65 KT 75 MPH
24H 13/0000Z 14.7N 146.1W 60 KT 70 MPH
36H 13/1200Z 15.4N 146.9W 60 KT 70 MPH
48H 14/0000Z 16.1N 147.3W 55 KT 65 MPH
72H 15/0000Z 17.9N 147.1W 50 KT 60 MPH
96H 16/0000Z 20.4N 145.4W 45 KT 50 MPH
120H 17/0000Z 22.6N 143.3W 35 KT 40 MPH

$$
FORECASTER POWELL


WTPA34 PHFO 120240
TCPCP4

BULLETIN
TROPICAL STORM NORA ADVISORY NUMBER 11
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP182015
500 PM HST SUN OCT 11 2015

…NORA CONTINUES MOVING WEST NORTHWESTWARD FAR SOUTHEAST OF
HAWAII…

SUMMARY OF 500 PM HST…0300 UTC…INFORMATION
———————————————-
LOCATION…13.5N 143.8W
ABOUT 860 MI…1385 KM ESE OF HILO HAWAII
MAXIMUM SUSTAINED WINDS…70 MPH…110 KM/H
PRESENT MOVEMENT…WNW OR 300 DEGREES AT 9 MPH…15 KM/H
MINIMUM CENTRAL PRESSURE…993 MB…29.33 INCHES

WATCHES AND WARNINGS
——————–
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

DISCUSSION AND 48-HOUR OUTLOOK
——————————
AT 500 PM HST…0300 UTC…THE CENTER OF TROPICAL STORM NORA WAS
LOCATED NEAR LATITUDE 13.5 NORTH…LONGITUDE 143.8 WEST. NORA IS
MOVING TOWARD THE WEST-NORTHWEST NEAR 9 MPH…15 KM/H. NORA WILL
GRADUALLY SLOW DOWN THROUGH MONDAY…WITH A TURN TOWARD THE
NORTHWEST FORECAST BY LATE MONDAY THROUGH TUESDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 70 MPH…110 KM/H…WITH HIGHER
GUSTS. NORA WILL STRENGTHEN A BIT THROUGH TONIGHT…BRIEFLY
BECOMING A HURRICANE…THEN BEGIN TO WEAKEN MONDAY AND TUESDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 70 MILES…110 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 993 MB…29.33 INCHES.

HAZARDS AFFECTING LAND
———————-
NONE

NEXT ADVISORY
————-
NEXT COMPLETE ADVISORY…1100 PM HST.

$$
FORECASTER POWELL
WTPA44 PHFO 120240
TCDCP4

TROPICAL STORM NORA DISCUSSION NUMBER 11
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP182015
500 PM HST SUN OCT 11 2015

NORA IS A COMPACT TROPICAL SYSTEM…AND THE CENTRAL DENSE OVERCAST
AREA HAS BECOME SMALLER THIS AFTERNOON. LOW CLOUD LINES APPEAR TO
PLACE THE LOW LEVEL CIRCULATION CENTER…LLCC…BENEATH THE EASTERN
EDGE OF DEEPEST CONVECTION. A 2339 UTC SSMI MICROWAVE PASS…WHILE
NOT CONCLUSIVE…MARGINALLY SUPPORTS THE INITIAL POSITION…BUT
CONFIDENCE IS NOT VERY HIGH WITHOUT AN INFRARED WARM SPOT OR A
VISIBLE EYE. THIS SAME SSMI PASS SHOWED A LACK OF AN EYEWALL ACROSS
THE EASTERN SEMICIRCLE. SUBJECTIVE DVORAK SATELLITE INTENSITY
ESTIMATES RANGED FROM 3.5…55 KT…FROM JTWC TO 4.0…65 KT…FROM
PHFO AND SAB. UW-CIMSS ADT REMAINED 3.9…63 KT. NORA LOOKS NO
BETTER ORGANIZED THAN IT DID THIS MORNING AND…WITH NO
COMPLETE EYEWALL DEPICTED IN MICROWAVE IMAGERY…WE WILL HOLD THE
INITIAL INTENSITY AT 60 KT FOR THIS ADVISORY.

ANIMATION AND SUCCESSIVE SSMI PASSES SEEM TO SHOW THAT NORA IS
MAINTAINING A MORE NORTHERLY TRACK THIS AFTERNOON THAN IT WAS
OVERNIGHT. INITIAL MOTION IS SET AT 300/08 KT…NOTICEABLY SLOWER
THAN BEFORE. TRACK GUIDANCE CONTINUES TO DEPICT NORA MOVING
WEST NORTHWESTWARD THROUGH 36 HOURS…ALONG THE SOUTHWEST FLANK OF
MID-LEVEL RIDGING TO THE NORTHEAST OF THIS SYSTEM. GUIDANCE THEN
RECURVES NORA NORTHWARD ON DAYS TWO AND THREE…THEN NORTHEASTWARD
ON DAYS FOUR AND FIVE AS A DEEP TROUGH NORTH OF HAWAII MOVES
EAST…WEAKENS THE RIDGE…AND SCOOPS NORA OUT OF THE DEEP TROPICS.
THE SPREAD IN TRACK GUIDANCE IS DUE TO DIFFERENCES IN INITIAL
MOTION AND FORWARD SPEED DURING RECURVATURE. IN SPITE OF THIS
UNCERTAINTY…ALL OF THE GUIDANCE EITHER RECURVES NORA NORTHEASTWARD
FAR FROM HAWAII…OR DECAPITATES NORA AND SHOVES THE REMNANTS WEST
SOUTHWESTWARD WITHIN THE TRADES.

INTENSITY GUIDANCE SHOWS THE WINDOW FOR STRENGTHENING WILL LIKELY
SLAM SHUT IN 12 HOURS. SHEAR ACROSS NORA HAS INCREASED INTO THE 15
TO 20 KT RANGE THIS AFTERNOON BUT…WITH SEA SURFACE TEMPERATURES
NEAR 29C…SHIPS AND LGEM ALLOW FOR A SMALL INTENSITY INCREASE
THROUGH TONIGHT. GUIDANCE THEN AGREES ON STEADY WEAKENING THROUGH
120 HOURS…WITH SHIPS DISSIPATING NORA AT 96 HOURS. WE WILL
CONTINUE TO PEAK NORA AT 65 KT…AS A HURRICANE…IN 12 HOURS.
HOWEVER…WE NOW FORECAST CONTINUED WEAKENING THEREAFTER.
FORECAST POSITIONS AND MAX WINDS

INIT 12/0300Z 13.5N 143.8W 60 KT 70 MPH
12H 12/1200Z 14.0N 144.9W 65 KT 75 MPH
24H 13/0000Z 14.7N 146.1W 60 KT 70 MPH
36H 13/1200Z 15.4N 146.9W 60 KT 70 MPH
48H 14/0000Z 16.1N 147.3W 55 KT 65 MPH
72H 15/0000Z 17.9N 147.1W 50 KT 60 MPH
96H 16/0000Z 20.4N 145.4W 45 KT 50 MPH
120H 17/0000Z 22.6N 143.3W 35 KT 40 MPH

$$
FORECASTER POWELL