EPAC : Norbert: Tropical Depression - Discussion

[HURAKAN]

637
ABPZ20 KNHC 302345
TWOEP
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
500 PM PDT TUE SEP 30 2008

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

THUNDERSTORM ACTIVITY ASSOCIATED WITH THE BROAD AREA OF LOW PRESSURE
LOCATED ABOUT 350 MILES SOUTH-SOUTHWEST OF THE GULF OF TEHUANTEPEC
HAS CHANGED LITTLE THIS AFTERNOON. CONDITIONS APPEAR SOMEWHAT
FAVORABLE FOR DEVELOPMENT AND THIS SYSTEM COULD BECOME A TROPICAL
DEPRESSION DURING THE NEXT COUPLE OF DAYS AS IT DRIFTS WESTWARD.

SHOWERS AND THUNDERSTORMS HAVE BECOME A LITTLE BETTER ORGANIZED IN
ASSOCIATION WITH THE LARGE LOW PRESSURE AREA LOCATED ABOUT 600
MILES SOUTH-SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA.
CONDITIONS APPEAR FAVORABLE FOR ADDITIONAL DEVELOPMENT AND THIS
SYSTEM COULD BECOME A TROPICAL CYCLONE BEFORE IT REACHES COOLER
WATERS IN A COUPLE OF DAYS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BROWN

[Chacor]

ABPZ20 KNHC 011130
TWOEP
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
500 AM PDT WED OCT 1 2008

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON NEWLY-FORMED
TROPICAL DEPRESSION FOURTEEN-E...LOCATED ABOUT 590 MILES SOUTHWEST
OF THE SOUTHERN TIP OF BAJA CALIFORNIA.

THUNDERSTORM ACTIVITY CONTINUES WITH THE BROAD AREA OF LOW PRESSURE
LOCATED A FEW HUNDRED MILES SOUTH OF ACAPULCO MEXICO. UPPER-LEVEL
WINDS ARE FORECAST TO BECOME MORE FAVORABLE FOR DEVELOPMENT OVER
THE NEXT DAY OR SO...AND THIS SYSTEM COULD BECOME A TROPICAL
DEPRESSION AS IT DRIFTS WESTWARD.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER FRANKLIN

Now RED on the GTWO.

[Chacor]

WTPN21 PGTW 011130
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
100 NM EITHER SIDE OF A LINE FROM 11.5N 97.4W TO 13.3N 100.3W
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 18 TO 23 KNOTS. METSAT IM-
AGERY AT 010600Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 11.6N 97.6W. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 07
KNOTS.
2. REMARKS: AN AREA OF CONVECTION NEAR 11.6N 97.6W, APPROXIMATELY
340 NM SOUTH-SOUTHEAST OF ACUPULCO, MEXICO, HAS PERSISTED OVER
THE PAST 12 HOURS. RECENT ANIMATED INFRARED SATELLITE IMAGERY
SHOWS DEEP CONVECTION DEVELOPING ALONG THE WESTERN PERIPHERY OF
A CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC) EVIDENT IN
A 010010Z QUIKSCAT PASS AND A 010916Z TRMM IMAGE. A SURGE OF
NORTHEASTERLY FLOW THROUGH THE GULF OF TUHUANTEPEC APPEARS TO BE
AIDING SPIN-UP OF THE SURFACE CIRCULATION. THIS DISTURBANCE
LIES EQUATORWARD OF AN UPPER LEVEL ANTICYCLONE AXIS, IN AN AREA
OF STRONG WESTWARD DIFFLUENCE ALOFT AND MODERATE BUT DECREASING
VERTICAL WIND SHEAR. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTI-
MATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1005 MB. BASED ON THE STRONG LOW LEVEL SIGNATURE AND
INCREASINGLY FAVORABLE UPPER LEVEL CONDITIONS, THE POTENTIAL FOR
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE
NEXT 24 HOURS IS GOOD.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED
BY 021130Z.//
NNNN

[HURAKAN]

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
500 PM PDT WED OCT 1 2008

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
STORM MARIE...LOCATED ABOUT 600 MILES SOUTHWEST OF THE SOUTHERN TIP
OF BAJA CALIFORNIA.

THE SHOWER ACTIVITY ASSOCIATED WITH THE AREA OF LOW PRESSURE
CENTERED A FEW HUNDRED MILES SOUTH OF ACAPULCO MEXICO HAS BECOME A
LITTLE BETTER ORGANIZED DURING THE DAY. THIS SYSTEM HAS THE
POTENTIAL TO BECOME A TROPICAL DEPRESSION TONIGHT OR THURSDAY AS IT
DRIFTS WESTWARD.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

PUBLIC ADVISORIES ON MAIRE ARE ISSUED UNDER WMO HEADER WTPZ34
AND UNDER AWIPS HEADER MIATCPEP4. FORECAST/ADVISORIES ON
MARIE ARE ISSUED UNDER WMO HEADER WTPZ24 AND UNDER AWIPS
HEADER MIATCMEP4.

$$
FORECASTER AVILA

[HURAKAN]

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1100 AM PDT FRI OCT 3 2008

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON STRENGTHENING
TROPICAL STORM MARIE...LOCATED ABOUT 875 MILES WEST-SOUTHWEST OF
THE SOUTHERN TIP OF BAJA CALIFORNIA.

SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A NEARLY STATIONARY AREA
OF LOW PRESSURE CENTERED ABOUT 225 MILES SOUTH OF ACAPULCO MEXICO
HAVE BECOME BETTER ORGANIZED DURING THE PAST FEW HOURS AND A
TROPICAL DEPRESSION COULD BE FORMING. IF THIS TREND CONTINUES
ADVISORIES WILL BE INITIATED LATER TODAY OR TONIGHT.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.


$$
FORECASTER BLAKE

[HURAKAN]

Best Track 0z:

EP, 91, 2008100400, , BEST, 0, 135N, 993W, 30, 1006

Back to 30 knots.

[HURAKAN]

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
500 PM PDT FRI OCT 3 2008

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON
RECENTLY-UPGRADED HURRICANE MARIE...LOCATED ABOUT 875 MILES
WEST-SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA.

SHOWER AND THUNDERSTORM ACTIVITY CONTINUES TO ORGANIZE AROUND THE
NEARLY STATIONARY AREA OF LOW PRESSURE CENTERED ABOUT 250 MILES
SOUTH OF ACAPULCO MEXICO. A TROPICAL DEPRESSION COULD BE
FORMING...AND IF THIS TREND CONTINUES...ADVISORIES WILL LIKELY BE
INITIATED LATER THIS EVENING.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.


$$
FORECASTER BERG/STEWART

[HURAKAN]

TCFA Re-issued!

[Chacor]

WTPZ25 KNHC 040248
TCMEP5
FIFTEEN-E FORECAST/ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152008
0300 UTC SAT OCT 04 2008

CENTER LOCATED NEAR 13.6N 99.4W AT 04/0300Z
POSITION ACCURATE WITHIN 20 NM

PRESENT MOVEMENT TOWARD THE NORTH OR 5 DEGREES AT 2 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1006 MB
MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 13.6N 99.4W AT 04/0300Z
AT 04/0000Z CENTER WAS LOCATED NEAR 13.5N 99.3W

FORECAST VALID 04/1200Z 13.7N 99.7W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 35NE 35SE 35SW 35NW.

FORECAST VALID 05/0000Z 13.9N 100.3W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 35NE 35SE 35SW 35NW.

FORECAST VALID 05/1200Z 14.3N 101.3W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 45NE 45SE 45SW 45NW.

FORECAST VALID 06/0000Z 14.7N 102.5W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 20NE 20SE 20SW 20NW.
34 KT... 45NE 45SE 45SW 45NW.

FORECAST VALID 07/0000Z 15.3N 103.7W
MAX WIND 65 KT...GUSTS 80 KT.
50 KT... 20NE 20SE 20SW 20NW.
34 KT... 60NE 50SE 45SW 60NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 200 NM
ON DAY 4 AND 225 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 08/0000Z 16.0N 105.0W
MAX WIND 65 KT...GUSTS 80 KT.

OUTLOOK VALID 09/0000Z 17.0N 106.5W
MAX WIND 65 KT...GUSTS 80 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 13.6N 99.4W

NEXT ADVISORY AT 04/0900Z

$$
FORECASTER STEWART

WTPZ45 KNHC 040321
TCDEP5
TROPICAL DEPRESSION FIFTEEN-E DISCUSSION NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152008
800 PM PDT FRI OCT 03 2008

THE BROAD LOW PRESSURE SYSTEM THAT HAS BEEN FESTERING SOUTH OF
SOUTHERN MEXICO FOR THE PAST 4 DAYS OR SO HAS FINALLY DEVELOPED
ENOUGH CONVECTIVE BANDING TO BE CLASSIFIED AS A TROPICAL
DEPRESSION. SATELLITE INTENSITY ESTIMATES ARE T2.0/30 KT AND
T1.5/25 KT FROM TAFB AND SAB...RESPECTIVELY. HOWEVER...A QUIKSCAT
OVERPASS EARLIER IN THE DAY INDICATED SOME 25-30 KT WIND VECTORS
OUTSIDE RAIN AREAS...AND CONVECTION HAS BECOME BETTER ORGANIZED AND
MORE CENTRALIZED SINCE THAT OVERPASS...ESPECIALLY SINCE 01Z.
THEREFORE...THE INITIAL INTENSITY IS SET AT 30 KT.

THE INITIAL MOTION IS A SLOW DRIFT TOWARD THE NORTH AT 02 KT. ALL OF
THE NHC MODEL GUIDANCE...EXCEPT FOR THE HWRF MODEL...TAKE THE
DEPRESSION SLOWLY TOWARD THE WEST-NORTHWEST OR NORTHWEST DURING THE
FORECAST PERIOD. HWRF TAKES THE CYCLONE IMMEDIATELY DUE NORTH AND
MOVES INTO THE SOUTH-CENTRAL COAST OF MEXICO IN 36-48 HOURS. THE
HWRF SCENARIO IS BEING DISCOUNTED AT THIS TIME DUE TO A LARGE-SCALE
SUBTROPICAL RIDGE FORECAST TO BUILD WESTWARD ACROSS EASTERN AND
CENTRAL MEXICO FROM THE ATLANTIC BASIN...WHICH IS EXPECTED TO FORCE
TD 15-E ON A GENERAL WEST-NORTHWESTWARD TRACK. ALL OF THE GLOBAL
MODELS AND THE GFDL MODEL AGREE ON THE DEVELOPMENT OF THIS
SYNOPTIC-SCALE STEERING PATTERN...ALBEIT A WEAK FLOW.

THE CYCLONE IS FORECAST TO REMAIN OVER NEAR-29C SSTS FOR ABOUT 72
HOURS AND UNDER MODEST EASTERLY VERTICAL SHEAR CONDITIONS OF 10-15
KT. THEREFORE...GRADUAL INTENSIFICATION IS FORECAST SIMILAR TO THE
SHIPS INTENSITY MODEL. THE OFFICIAL INTENSITY FORECAST IS SLIGHTLY
HIGHER THAN THE SHIPS MODEL AND NEARLY TWICE THE ICON INTENSITY
MODEL FORECAST DUE TO THE DEPRESSION EXPECTED TO MOVE SLOWER THAN
THE BAMM MODEL IS INDICATING...WHICH WAS THE MODEL USED TO GENERATE
THE SHIPS MODEL OUTPUT. THE SLOWER FORECAST TRACK IS EXPECTED TO
KEEP THE SYSTEM OVER WARMER WATER AND IN WEAKER SHEAR CONDITIONS
LONGER THAN THE BAMM-SHIPS MODEL IS FORECASTING.

FORECAST POSITIONS AND MAX WINDS

INITIAL 04/0300Z 13.6N 99.4W 30 KT
12HR VT 04/1200Z 13.7N 99.7W 35 KT
24HR VT 05/0000Z 13.9N 100.3W 40 KT
36HR VT 05/1200Z 14.3N 101.3W 45 KT
48HR VT 06/0000Z 14.7N 102.5W 55 KT
72HR VT 07/0000Z 15.3N 103.7W 65 KT
96HR VT 08/0000Z 16.0N 105.0W 65 KT
120HR VT 09/0000Z 17.0N 106.5W 65 KT

$$
FORECASTER STEWART

[Chacor]

WTPZ45 KNHC 040839
TCDEP5
TROPICAL DEPRESSION FIFTEEN-E DISCUSSION NUMBER 2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152008
200 AM PDT SAT OCT 04 2008

SHORTWAVE INFRARED SATELLITE IMAGERY AND AN AMSU-B MICROWAVE
OVERPASS DEPICT AN EXPOSED SURFACE CIRCULATION CENTER WELL TO THE
EAST OF AN ISOLATED BANDING FEATURE. UW-CIMSS SHEAR PRODUCT
INDICATES 15 TO 20 KT OF EASTERLY SHEAR AFFECTING THE CLOUD
PATTERN. DVORAK SATELLITE INTENSITY ESTIMATES OF 25 TO 35 KT AND A
0420Z ASCAT SWATH REVEALING A SIMILAR INTENSITY OVER THE NORTH
QUADRANT SUPPORT HOLDING THE INITIAL INTENSITY AT 30 KT.

IT'S INTERESTING TO NOTE THAT THE GFS IS DEVELOPING A TROPICAL
CYCLONE IN 36 HOURS EAST OF THE DEPRESSION AND 20 TO 30 KT OF
SOUTHEASTERLY SHEAR...APPARENTLY FROM THE CYCLONES' OUTFLOW
PATTERN. THIS PARTICULAR FEATURE ALSO APPEARS TO BE INFLUENCING
THE SHIPS MODEL. SINCE THERE IS NO EVIDENCE YET THAT THIS
GFS-FORECAST CYCLONE IS ACTUALLY DEVELOPING...THE INTENSITY
FORECAST FOLLOWS THE INTENSITY CONSENSUS MODEL...STRENGTHENING THE
DEPRESSION TO A HURRICANE IN 4 DAYS. THE INTENSITY FORECAST IS
SLIGHTLY HIGHER THAN THE SHIPS MODEL BEYOND DAY 3.

THE ESTIMATED INITIAL MOTION APPEARS TO BE A TEMPORARY EASTWARD
DRIFT WITHIN THE SHALLOW LAYER CROSS-EQUATORIAL WESTERLY FLOW. A
LARGE AMPLITUDE MID- TO UPPER LEVEL TROUGH EXTENDING FROM CENTRAL
MEXICO TO JUST NORTH OF THE DEPRESSION IS ALSO SUPPORTING THIS
EASTWARD MOTION. THE GLOBAL MODELS ALL SUGGEST THAT A SOUTHWEST
EXTENSION OF THE SUBTROPICAL RIDGE WILL BUILD IN OVER THE SOUTHWEST
GULF AND SOUTHERN MEXICO IN RESPONSE TO THE TROUGH MOVING NORTHEAST
OUT OF THE AREA AROUND 24 TO 36 HOUR PERIOD. THIS EXPECTED CHANGE
IN THE SYNOPTIC STEERING PATTERN SHOULD CAUSE THE SYSTEM TO TURN
BACK TOWARD THE WEST-NORTHWEST. THROUGH THE REMAINING FORECAST
PERIOD...THE DYNAMICAL MODELS ALL SHOW A CONTINUED WEST-
NORTHWESTWARD MOTION ALBEIT WITH A DISAGREEMENT IN FORWARD SPEED.
THE HWRF DEPICTS A SIGNIFICANTLY STRONGER RIDGE ESTABLISHING OVER
MEXICO AS COMPARED TO THE OTHER GUIDANCE. THE OFFICIAL FORECAST IS
QUITE SIMILAR TO THE PREVIOUS TRACK AND IS BASED ON A CONSENSUS OF
THE DYNAMICAL MODELS...BUT A BIT SLOWER THAN THE HWRF.



FORECAST POSITIONS AND MAX WINDS

INITIAL 04/0900Z 13.6N 98.8W 30 KT
12HR VT 04/1800Z 13.7N 99.0W 35 KT
24HR VT 05/0600Z 13.8N 99.7W 40 KT
36HR VT 05/1800Z 13.9N 100.6W 45 KT
48HR VT 06/0600Z 14.1N 101.6W 50 KT
72HR VT 07/0600Z 15.0N 103.5W 55 KT
96HR VT 08/0600Z 16.0N 105.0W 65 KT
120HR VT 09/0600Z 17.0N 106.5W 65 KT

$$
FORECASTER ROBERTS

[HURAKAN]

04/1145 UTC 14.0N 99.5W T2.0/2.0 15E -- East Pacific Ocean

Closer to Norbert.

[cycloneye]

WTPZ45 KNHC 041434
TCDEP5
TROPICAL DEPRESSION FIFTEEN-E DISCUSSION NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152008
800 AM PDT SAT OCT 04 2008

VISIBLE SATELLITE IMAGES CONFIRMED THAT THE LOW-LEVEL CENTER IS
LOCATED TO THE EAST OF A CYCLONICALLY CURVED BAND. THE OVERALL
CIRCULATION IS GRADUALLY IMPORVING. THE OUTFLOW IS ONLY PRESENT IN
THE WESTERN SEMICIRCLE DUE TO EASTERLY SHEAR. BOTTOM LINE IS THAT
THE CLOUD PATTERN HAS NOT CHANGED VERY MUCH AND THE SYSTEM
CONTINUES AS A 30 KT TROPICAL DEPRESSION. THIS IS BASED
ON DVORAK ESTIMATES.

BOTH INTENSITY AND TRACK FORECASTS ARE COMPLICATED. THE DEPRESSION
IS EMBEDDED WITHIN A COMPLEX AND WEAK STEERING FLOW...AND IT HAS
BEEN DRIFTING WESTWARD FOR THE PAST SEVERAL HOURS. ACCORDING TO THE
GFS...THE STEERING AND THE UPPER-LEVEL WINDS WILL LIKELY BE
CONTROLLED BY A MUCH LARGER DISTURBANCE TO THE EAST OF THE
DEPRESSION. IN FACT...THE GFS ASSUMES THAT THE DEPRESSION WILL BE
ABSORBED BY A NEW CYCLONE IN A FEW DAYS. HOWEVER...THE REST OF THE
DYNAMICAL MODELS KEEP THE DEPRESSION AS THE ONLY CYCLONE AND MOVE
IT SLOWLY WESTWARD. ALTHOUGH RECENT SATELLITE IMAGES INDICATE THAT
THE DISTURBANCE TO THE EAST COULD BE DEVELOPING AS SUGGESTED BY THE
GFS...THE OFFICIAL FORECAST FOLLOWS ALL MODELS BUT THE GFS AND
KEEPS THE DEPRESSION ON A SLOW WEST TO WEST-NORTHWEST TRACK WITH A
GRADUAL INTENSIFICATION. THIS IS CONSISTENT WITH THE PREVIOUS
OFFICIAL FORECAST...BUT I COULD BE SORRY LATER ON THAT I DID NOT
FOLLOW THE RELIABLE GFS.


FORECAST POSITIONS AND MAX WINDS

INITIAL 04/1500Z 14.0N 99.5W 30 KT
12HR VT 05/0000Z 14.1N 99.7W 35 KT
24HR VT 05/1200Z 14.2N 100.5W 35 KT
36HR VT 06/0000Z 14.5N 101.5W 40 KT
48HR VT 06/1200Z 15.0N 102.5W 45 KT
72HR VT 07/1200Z 16.0N 104.5W 55 KT
96HR VT 08/1200Z 16.5N 106.5W 65 KT
120HR VT 09/1200Z 17.0N 108.0W 65 KT

$$
FORECASTER AVILA

[HURAKAN]

[cycloneye]

WTPZ45 KNHC 042044
TCDEP5
TROPICAL DEPRESSION FIFTEEN-E DISCUSSION NUMBER 4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152008
200 PM PDT SAT OCT 04 2008

THE CLOUD PATTERN HAS NOT BECOME ANY BETTER ORGANIZED TODAY. THE
LOW-LEVEL CENTER CONTINUES TO BE SEPARATED FROM THE MAIN CONVECTION
AND THE UPPER-LEVEL OUTFLOW IS ESTABLISHED IN THE WESTERN
SEMICIRCLE ONLY. BASED ON THE BLEND OF DVORAK ESTIMATES...THE
INITIAL INTENSITY REMAINS AT 30 KNOTS.

AS EXPRESSED THIS MORNING...BOTH INTENSITY AND TRACK FORECASTS ARE
COMPLICATED AND HIGHLY UNCERTAIN. THE UK AND ECMWF GLOBAL MODELS
KEEP THE CYCLONE ON A GENERAL WESTWARD TRACK WITH A POTENTIAL
THREAT TO MEXICO EVENTUALLY. THE GFS DEVELOPS ANOTHER CYCLONE TO
THE EAST AND THE DEPRESSION BECOMES ABSORBED BY IT. EVEN THE GFDL
AND HWRF ARE COMPLETELY DIFFERENT. THE GFDL KEEPS THE CYCLONE MOVING
WESTWARD AND THE HWRF TURNS IT NORTH OVER BAJA CALIFORNIA. I AM
STUCK BETWEEN A ROCK AND A HARD PLACE SINCE I HAVE TO CHOOSE ONE OF
THESE RELIABLE MODEL SOLUTIONS.

THE DEPRESSION HAS BEGUN TO MOVE WESTWARD ABOUT 4 KNOTS. THE UK AND
ECMWF MODELS GRADUALLY DEVELOP A MIDDLE-LEVEL RIDGE OVER THE
WESTERN UNITED STATES AND MEXICO. THIS PATTERN SHOULD KEEP THE
CYCLONE ON A SLOW WEST TO WEST-NORTHWEST TRACK THROUGH FIVE DAYS.
THE OFFICIAL FORECAST FOLLOWS THIS SOLUTION SINCE IT LOOKS MORE
REALISTIC AT THIS TIME AND BECAUSE THE NEW CYCLONE PRODUCED BY THE
GFS APPEARS TO BE TOO STRONG. WE SHALL SEE.

IN ANY CASE...THERE WILL BE A PERSISTENT EASTERLY SHEAR THROUGH FIVE
DAYS...BUT NOT STRONG ENOUGH TO HALT A GRADUAL INTENSIFICATION. THE
OFFICIAL INTENSITY FORECAST FOLLOWS THE SHIPS GUIDANCE AND ASSUMES
THAT THE DEPRESSION WILL NOT BE ABSORBED BY THE NEW GFS CYCLONE.


FORECAST POSITIONS AND MAX WINDS

INITIAL 04/2100Z 14.2N 100.3W 30 KT
12HR VT 05/0600Z 14.3N 101.1W 35 KT
24HR VT 05/1800Z 14.5N 102.5W 40 KT
36HR VT 06/0600Z 15.0N 103.5W 45 KT
48HR VT 06/1800Z 15.5N 104.5W 50 KT
72HR VT 07/1800Z 16.0N 106.5W 60 KT
96HR VT 08/1800Z 16.5N 108.5W 60 KT
120HR VT 09/1800Z 17.5N 111.0W 60 KT

$$
FORECASTER AVILA

[RattleMan]

EP, 15, 2008100418, , BEST, 0, 141N, 1001W, 30, 1006, TD, 0, , 0, 0, 0, 0, 1010, 180, 35, 40, 0, E, 0, , 0, 0, FIFTEEN, M,
EP, 15, 2008100500, , BEST, 0, 142N, 1006W, 35, 1005, TS, 34, NEQ, 30, 30, 30, 30, 1010, 180, 30, 0, 0, E, 0, , 0, 0, NORBERT, M,

[cycloneye]

TTAA00 KNHC DDHHMM
TROPICAL STORM NORBERT DISCUSSION NUMBER 5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152008
800 PM PDT SAT OCT 04 2008

DEEP CONVECTION HAS INCREASED AND BECOME BETTER ORGANIZED AROUND THE
LOW-LEVEL CENTER...AND THE DEPRESSION HAS STRENGTHENED INTO
TROPICAL STORM NORBERT. THE INITIAL INTENSITY OF 35 KT IS BASED ON
A DVORAK SATELLITE INTENSITY ESTIMATE OF T2.5/35 KT FORM TAFB...AND
A 04/1652Z ASCAT OVERPASS THAT CAME IN AFTER THE 21Z ADVISORY WAS
ISSUED...WHICH SHOWED SEVERAL 30- TO 34-KT WIND VECTORS IN THE
NORTHWEST QUADRANT. SINCE THAT THE TIME OF THE ASCAT OVERPASS...
HOWEVER...THE CONVECTIVE ORGANIZATION OF THE SYSTEM HAS IMPROVED.

THE INITIAL MOTION ESTIMATE IS 280/05. AVAILABLE MODEL GUIDANCE IS
IN GOOD AGREEMENT ABOUT A SLOW WESTWARD TO WEST-NORTHWESTWARD
MOTION THROUGH 96 HOURS AS NORBERT MOVES AROUND THE SOUTHWESTERN
PERIPHERY OF A SUBTROPICAL RIDGE FORECAST TO BUILD WESTWARD TO THE
NORTH OF THE CYCLONE. BY 120 HOURS...A SLOW TURN TOWARD THE
NORTHWEST IS EXPECTED AS A WEAK MID-LEVEL TROUGH IS FORECAST TO DIG
SOUTHWARD ALONG THE CALIFORNIA COAST AND ERODE THE WESTERN PORTION
OF THE MID-LEVEL RIDGE. THE OFFICIAL FORECAST TRACK IS CLOSE TO THE
PREVIOUS TRACK AND IS SLIGHTLY NORTH OF THE NHC MODEL CONSENSUS.

MODERATE VERTICAL SHEAR IS FORECAST TO WEAKEN THROUGH 72 HOURS AS
NORBERT REMAINS OVER SSTS GREATER THAN 28C. ALSO...AS NORBERT MOVES
FARTHER WEST...THE NEGATIVE EFFECTS OF DRY EASTERLY DOWNSLOPE AIR
COMING FROM THE GULF OF TEHUANTEPEC SHOULD BE REDUCED. THEREFORE...
GRADUAL STRENGTHENING IS FORECAST SIMILAR TO THE SHIPS AND ICON
INTENSITY MODELS. IT SHOULD BE NOTED THAT THE HWRF MODEL MAKES
NORBERT A 102-KT MAJOR HURRICANE ON DAY 4. HOWEVER...THIS SCENARIO
IS BEING DISCOUNTED AT THIS TIME DUE TO VERTICAL WIND SHEAR
EXPECTED TO INCREASE TO MORE THAN 20 KT AFTER 72 HOURS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 05/0300Z 14.2N 100.9W 35 KT
12HR VT 05/1200Z 14.4N 101.8W 40 KT
24HR VT 06/0000Z 14.7N 103.0W 45 KT
36HR VT 06/1200Z 15.0N 104.0W 50 KT
48HR VT 07/0000Z 15.4N 105.3W 55 KT
72HR VT 08/0000Z 16.0N 107.0W 65 KT
96HR VT 09/0000Z 17.0N 109.5W 65 KT
120HR VT 10/0000Z 18.5N 111.5W 65 KT

$$
FORECASTER STEWART

[Chacor]

Isn't the new format to have the name of the system first? Why is there inconsistency?

[cycloneye]

Isn't the new format to have the name of the system first? Why is there inconsistency?

Edited the title to the format.

[Chacor]

New forecast is for 75 kt.

WTPZ45 KNHC 050858
TCDEP5
TROPICAL STORM NORBERT DISCUSSION NUMBER 6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152008
200 AM PDT SUN OCT 05 2008

THE OVERALL CLOUD PATTERN ASSOCIATED WITH NORBERT HAS GRADUALLY
IMPROVED DURING THE PAST FEW HOURS. SATELLITE IMAGERY SHOWS THAT
CONVECTIVE BANDS HAVE DEVELOPED OVER THE SOUTH AND SOUTHEASTERN
PORTION OF THE STORM. DVORAK INTENSITY ESTIMATES FROM TAFB AND
SAB HAVE INCREASED TO 45 AND 35 KT...RESPECTIVELY. THEREFORE...THE
INITIAL INTENSITY IS RAISED TO 40 KT. THE CENTER POSITION HAS BEEN
ADJUSTED SLIGHTLY SOUTH OF THE EARLIER ESTIMATES BASED ON RECENT
MICROWAVE IMAGERY. THE INITIAL MOTION ESTIMATE IS 270/6. NORBERT
IS EXPECTED TO MOVE SLOWLY WEST TO WEST-NORTHWESTWARD DURING THE
NEXT SEVERAL DAYS...TO THE SOUTH OF A NARROW MID-LEVEL RIDGE.
LATE IN THE FORECAST PERIOD AS A TROUGH BEGINS TO DIG SOUTHWARD
ALONG THE WEST COAST OF THE UNITED STATES...THE RIDGE IS FORECAST
TO GRADUALLY WEAKEN. THIS SHOULD ALLOW NORBERT TO TURN MORE TOWARD
THE NORTHWEST. IN GENERAL...THE FORECAST GUIDANCE AGREES WITH THIS
SCENARIO...BUT AT VARYING SPEEDS. THE HWRF AND UKMET ARE FASTER
AND MOVE NORBERT IN THE VICINITY OF THE SOUTHERN BAJA PENINSULA IN
4-5 DAYS...WHILE THE GFDL...ECMWF...AND NOGAPS ARE SOMEWHAT SLOWER.
THE GFS CONTINUES TO BE MUCH SLOWER ON ITS WESTWARD PROGRESSION OF
THE STORM AS IT PREDICTS SOME INTERACTION BETWEEN NORBERT AND THE
DISTURBANCE TO THE EAST. THE OFFICIAL FORECAST LEANS TOWARD THE
00Z ECMWF AND NOGAPS SOLUTIONS...BUT REMAINS A LITTLE SLOWER THAN
THE MODEL CONSENSUS.

SHEAR IS FORECAST TO BECOME LIGHT AS NORBERT REMAINS OVER SSTS
GREATER THAN 28C FOR THE NEXT SEVERAL DAYS. THEREFORE...
STRENGTHENING IS EXPECTED AND THE OFFICIAL FORECAST FOLLOWS THE
GUIDANCE WHICH UNANIMOUSLY CALL FOR NORBERT TO REACH HURRICANE
STATUS IN ABOUT 36-48 HOURS. THE NEW FORECAST IS CLOSEST TO THE
SHIPS AND LGEM GUIDANCE AND IS A LITTLE BELOW THE GFDL AND MUCH
MORE AGGRESSIVE HWRF MODEL. IT SHOULD BE NOTED...THAT THERE IS
SOME POTENTIAL FOR RAPID INTENSIFICATION DURING THE NEXT DAY OR SO
AS THE SHIPS RI INDEX INDICATES THAT THE CHANCE OF A 30 KT OR
GREATER INCREASE IN INTENSITY IS ABOUT 3 TIMES THE SAMPLE MEAN.

FORECAST POSITIONS AND MAX WINDS

INITIAL 05/0900Z 14.2N 101.4W 40 KT
12HR VT 05/1800Z 14.3N 102.3W 50 KT
24HR VT 06/0600Z 14.6N 103.5W 60 KT
36HR VT 06/1800Z 15.0N 104.7W 65 KT
48HR VT 07/0600Z 15.4N 105.8W 70 KT
72HR VT 08/0600Z 16.2N 108.0W 75 KT
96HR VT 09/0600Z 17.5N 110.2W 75 KT
120HR VT 10/0600Z 19.5N 112.0W 75 KT

$$
FORECASTER BROWN

[cycloneye]

000
WTPZ45 KNHC 051439
TCDEP5
TROPICAL STORM NORBERT DISCUSSION NUMBER 7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152008
800 AM PDT SUN OCT 05 2008

NORBERT'S CLOUD PATTERN CONTINUES TO SHOW AN INCREASE IN
ORGANIZATION WITH THE CENTER NOW SITUATED BENEATH A CDO FEATURE.
DVORAK SATELLITE INTENSITY ESTIMATES HAVE INCREASED TO 45 KT FROM
BOTH TAFB AND SAB BUT THE INITIAL INTENSITY IS SET SLIGHTLY
HIGHER...AT 50 KT...AS A COMPROMISE BETWEEN THE AFOREMENTIONED
SUBJECTIVE DVORAK ESTIMATES AND OBJECTIVE ESTIMATES FROM THE
UNIVERSITY OF WISCONSIN. NORBERT IS EXPECTED TO BE OVER WARM
WATERS AND WITHIN A RELATIVELY LOW VERTICAL SHEAR ENVIRONMENT FOR
THE NEXT COUPLE OF DAYS SO FURTHER INTENSIFICATION IS ANTICIPATED.
HOWEVER...THE AMOUNT OF INTENSIFICATION REMAINS UNCLEAR WITH A
SPREAD OF NEARLY 55 KT IN THE VARIOUS INTENSITY MODELS AT DAY 3.
FURTHER COMPLICATING THE INTENSITY FORECAST IS THE UNCERTAINTY IN
FORWARD SPEED THAT ARISES AT THE EXTENDED PERIODS AS NORBERT
APPROACHES COOLERS WATERS AND A STABLE AIRMASS NORTH OF 20 DEGREES
NORTH LATITUDE. GIVEN THE PRESENT TREND IN SATELLITE IMAGERY...THE
OFFICIAL FORECAST SHOWS NORBERT REACHING PEAK INTENSITY SOONER THAN
THE PREVIOUS ADVISORY AND IS IN CLOSEST AGREEMENT WITH THE LGEM AND
GFDL MODELS.

THERE HAVE BEEN NO RECENT MICROWAVE PASSES RESULTING IN A SOMEWHAT
UNCERTAIN CENTER POSITION ESTIMATE. SINCE THE OVERALL CLOUD MASS
APPEARS TO BE MOVING MORE TOWARDS THE WEST-NORTHWEST...THE INITIAL
MOTION IS NOW ESTIMATED TO BE 290/7. A LARGE DEEP-LAYER TROUGH IS
CURRENTLY MOVING EASTWARD OVER THE WESTERN HALF OF THE U.S. WITH A
NARROW SLIVER OF A MID-LEVEL RIDGE EXTENDING WESTWARD FROM MEXICO
JUST TO NORTH OF NORBERT. THE SHORT-TERM TRACK WILL BE DICTATED BY
WHETHER OR NOT THIS NARROW RIDGE REMAINS IN PLACE AS THE LARGER
TROUGH PASSES TO THE NORTH. MOST OF THE DYNAMICAL MODELS MAINTAIN
SUFFICIENT RIDGING TO THE NORTH TO KEEP THE CYCLONE ON A GENERAL
WEST-NORTHWESTWARD HEADING FOR 2-3 DAYS. ONLY THE UKMET MODEL
SHOWS THE RIDGE BREAKING DOWN ALLOWING NORBERT TO TRACK MORE
TOWARDS THE NORTH...CLOSER TO THE COAST OF MEXICO. BY DAYS 4 AND
5...GLOBAL MODELS ALL FORECAST A MIDDLE TO UPPER-LEVEL CUTOFF LOW
TO FORM SEVERAL HUNDRED MILES WEST OF THE BAJA PENINSULA...
RESULTING IN THE CYCLONE TURNING TOWARD THE NORTHWEST OR NORTH.
HOWEVER...THE MODELS HAVE CONSIDERABLE SPREAD IN FORWARD SPEED AT
THESE EXTENDED RANGES.

FORECAST POSITIONS AND MAX WINDS

INITIAL 05/1500Z 14.6N 101.9W 50 KT
12HR VT 06/0000Z 14.8N 102.8W 60 KT
24HR VT 06/1200Z 15.2N 104.0W 65 KT
36HR VT 07/0000Z 15.6N 105.1W 70 KT
48HR VT 07/1200Z 16.1N 106.3W 75 KT
72HR VT 08/1200Z 17.0N 108.5W 75 KT
96HR VT 09/1200Z 19.0N 111.0W 70 KT
120HR VT 10/1200Z 21.5N 112.5W 65 KT

$$
FORECASTER RHOME