ATL: BRET - Remnants - Discussion

[HURAKAN]

URNT15 KNHC 201935
AF307 0702A BRET HDOB 32 20110720
192600 3115N 07355W 8440 01570 0103 +169 +151 326027 027 /// /// 03
192630 3112N 07358W 8431 01574 0105 +165 +153 330026 028 /// /// 03
192700 3110N 07359W 8433 01575 0106 +166 +158 325030 032 /// /// 03
192730 3109N 07400W 8423 01582 0106 +163 //// 317034 035 /// /// 05
192800 3107N 07400W 8438 01569 //// +149 //// 308034 035 /// /// 05
192830 3106N 07401W 8440 01565 //// +142 //// 293033 035 /// /// 05
192900 3104N 07402W 8427 01577 0108 +152 //// 296033 035 /// /// 05
192930 3103N 07403W 8430 01576 0109 +161 //// 299029 030 /// /// 05
193000 3103N 07405W 8425 01581 0110 +160 //// 297029 029 /// /// 05
193030 3102N 07406W 8425 01589 0118 +160 //// 298027 028 /// /// 05
193100 3101N 07408W 8429 01586 0117 +165 +160 292025 026 /// /// 03
193130 3101N 07410W 8417 01604 0122 +167 +153 297023 024 /// /// 03
193200 3100N 07412W 8429 01598 0128 +168 +146 298025 025 /// /// 03
193230 3058N 07414W 8429 01598 0131 +166 +140 299025 025 /// /// 03
193300 3057N 07416W 8429 01600 0136 +161 +147 295026 027 /// /// 03
193330 3055N 07418W 8432 01597 0136 +161 +144 294026 026 /// /// 03
193400 3054N 07420W 8430 01600 0137 +164 +131 295026 026 /// /// 03
193430 3052N 07421W 8430 01600 0141 +161 +128 298025 026 /// /// 03
193500 3051N 07424W 8364 01654 0127 +157 +137 295023 024 /// /// 03
193530 3051N 07426W 8179 01848 0129 +146 +127 297021 021 /// /// 03

Plane seems to be lifting

[KWT]

Bret is slowly winding down, still quite a cool system to track in July and quite close to the US as well when it was in its formative stages...

[cycloneye]

TROPICAL STORM BRET DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011
500 PM EDT WED JUL 20 2011

AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT FOUND THAT BRET HAS
WEAKENED A LITTLE. THE MAXIMUM 850 MB FLIGHT-LEVEL WINDS WERE 45
KT IN THE SOUTHEASTERN QUADRANT...AND THE CENTRAL PRESSURE WAS 1005
MB ON BOTH PASSES THROUGH THE CENTER. BASED ON THIS AND DATA FROM
A 1521 UTC ASCAT OVERPASS...THE INITIAL INTENSITY IS REDUCED TO 40
KT. WHILE THE SYSTEM IS STILL GENERATING CONVECTION SOUTH OF THE
CENTER...THE INTENSITY FORECAST CALLS FOR ADDITIONAL WEAKENING AS
DRY MID/UPPER-LEVEL AIR ADVECTS INTO THE CYCLONE FROM THE
NORTHWEST. BRET IS NOW FORECAST TO WEAKEN TO A REMNANT LOW IN 48
HR AND DISSIPATE COMPLETELY BY 72 HR.

AIRCRAFT AND SATELLITE DATA INDICATE THAT THE CENTER JOGGED TO THE
EAST THIS AFTERNOON. HOWEVER...THE OVERALL MOTION REMAINS
GENERALLY NORTHEASTWARD...050/7. BRET REMAINS EMBEDDED IN
LOW/MID-LEVEL SOUTHWESTERLY FLOW ON THE NORTH SIDE OF THE
SUBTROPICAL RIDGE...AND THIS PATTERN SHOULD PRODUCE A NORTHEASTWARD
MOTION UNTIL THE SYSTEM DISSIPATES. THE NEW FORECAST TRACK IS
SIMILAR TO THE PREVIOUS TRACK...BUT NUDGED A LITTLE TO THE EAST
BASED ON THE INITIAL POSITION.

FORECAST POSITIONS AND MAX WINDS

INIT 20/2100Z 31.9N 73.0W 40 KT 45 MPH
12H 21/0600Z 32.7N 72.0W 40 KT 45 MPH
24H 21/1800Z 34.3N 70.3W 35 KT 40 MPH
36H 22/0600Z 35.9N 68.0W 30 KT 35 MPH
48H 22/1800Z 37.8N 64.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 23/1800Z...DISSIPATED

$$
FORECASTER BEVEN

[cycloneye]

TROPICAL STORM BRET DISCUSSION NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011
1100 PM AST WED JUL 20 2011

FOR THE PAST SEVERAL HOURS...BRET HAS LOST MUCH OF THE DEEP
CONVECTION THAT WAS LOCATED SOUTH OF ITS EXPOSED LOW-LEVEL
CENTER...AND NOW ONLY A FEW THUNDERSTORMS REMAIN. OBJECTIVE 3-HOUR
ADT NUMBERS ARE CURRENTLY T2.6...AND THE RAW NUMBERS ARE MUCH
LOWER. THE INITIAL INTENSITY IS THEREFORE LOWERED TO 35 KT.

NORTHERLY SHEAR OVER BRET IS BRUTAL. THE SHIPS/LGEM DIAGNOSTICS
SHOW ABOUT 30-35 KT OF SHEAR AFFECTING THE SYSTEM...AND THESE
VALUES COULD INCREASE FURTHER OVER THE NEXT 12-24 HOURS. WITH
WATER VAPOR IMAGERY SHOWING AN AREA OF STRONG SUBSIDENCE MOVING
SOUTHWARD TOWARDS THE CYCLONE...BRET WILL LIKELY STRUGGLE TO
MAINTAIN SIGNIFICANT DEEP CONVECTION OVER THE NEXT DAY. THE
OFFICIAL FORECAST ESSENTIALLY MIRRORS THE STATISTICAL-DYNAMICAL
MODELS...AND BRET COULD DEGENERATE INTO A REMNANT LOW BY 36
HOURS...IF NOT SOONER. DISSIPATION IS NOW EXPECTED BY 48 HOURS.

AFTER JOGGING TO THE EAST EARLIER THIS AFTERNOON...BRET IS NOW
WOBBLING A BIT TO THE NORTH. THE AVERAGE MOTION REMAINS
NORTHEASTWARD WITH A BIT OF AN ACCELERATION AT 045/8. THE TRACK
GUIDANCE IS IN GENERALLY GOOD AGREEMENT IN SHOWING ACCELERATION
WITHIN FASTER MID-LATITUDE SOUTHWESTERLIES...AND THE NEW OFFICIAL
FORECAST WAS ADJUSTED JUST A LITTLE TO THE EAST OF THE PREVIOUS ONE
TO BE CLOSE TO THE FASTER-MOVING GFS AND ECMWF.

FORECAST POSITIONS AND MAX WINDS

INIT 21/0300Z 32.8N 72.6W 35 KT 40 MPH
12H 21/1200Z 33.9N 70.9W 35 KT 40 MPH
24H 22/0000Z 35.5N 68.5W 30 KT 35 MPH
36H 22/1200Z 37.2N 65.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 23/0000Z...DISSIPATED

$$
FORECASTER BERG

[HURAKAN]

exposed

[beoumont]

Any reason why the BAM models are consistently west of the mean model track?

This might help explain why the BAMs often perform as you note. (IE: 2 of the 3 BAMs are basically not relevant to any specific system.).

BAMS - the BAM Shallow, this version averages winds from 5,000 to 10,000 feet (850 - 700 mb). The BAMS is best-used for tropical disturbances/tropical waves or tropical depressions. Such systems are very shallow in nature, moving with the lower-level winds.

BAMM - the BAM Medium, this version averages winds from 10,000 to 24,500 feet (850 - 400 mb). The BAMM is best-used for tropical storms of weak to moderate strength or disorganized hurricanes. Tropical storms are generally steered by the mid-level steering flow.

BAMD - the BAM Deep, this version averages winds from 24,500 to up to 47,000 feet (850 - 200 mb). The BAMD is best used for well-organized and/or stronger hurricanes. Such hurricanes are steered by the mid-level to upper-level wind flow.

[somethingfunny]

Aren't the BAM suite based off of GFS model data?

[Blown Away]

Torture watching Bret!

[KWT]

Just a anaked swirl now, probably won't last too much longer as a TS, Cindy will probably even outlive it in that respect.

[cycloneye]

12z Best Track

Still hanging on as a Tropical Storm.

AL, 02, 2011072112, , BEST, 0, 335N, 711W, 35, 1007, TS

[cycloneye]

TROPICAL STORM BRET DISCUSSION NUMBER 16
NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011
1100 AM AST THU JUL 21 2011

WHILE BRET CONTINUES TO GENERATE A STRONG CONVECTIVE CLUSTER SOUTH
OF THE EXPOSED LOW-LEVEL CENTER...THE SYSTEM IS GRADUALLY LOSING
ORGANIZATION AS IT REMAINS AFFECTED BY NORTHERLY VERTICAL WIND
SHEAR. THERE IS NO RECENT DATA FROM NEAR THE CENTER. HOWEVER...
TROPICAL-STORM WINDS COULD STILL BE OCCURRING IN AND NEAR THE
CONVECTION BASED ON A 1-MINUTE WIND OF 33 KT RECENTLY OBSERVED AT
BUOY 41048. THUS...THE INITIAL INTENSITY REMAINS A POSSIBLY
GENEROUS 35 KT.

THE INITIAL MOTION IS 055/8. THERE IS NO SIGNIFICANT CHANGE TO THE
PREVIOUS FORECAST TRACK OR REASONING. BRET SHOULD MOVE
NORTHEASTWARD IN THE FLOW ON THE NORTH SIDE OF THE SUBTROPICAL
RIDGE UNTIL IT DISSIPATES...WITH A GRADUAL INCREASE IN FORWARD
SPEED DURING THAT TIME. THE NEW FORECAST TRACK IS SIMILAR TO THE
PREVIOUS ADVISORY.

BRET IS MOVING THROUGH AN AREA OF MID/UPPER-LEVEL DRY AIR...AND IT
IS EXPECTED TO ENCOUNTER GRADUALLY DECREASING SEA SURFACE
TEMPERATURES ALONG THE FORECAST TRACK. THIS COMBINATION IS LIKELY
TO CAUSE THE CYCLONE TO WEAKEN EVEN THOUGH THE SHEAR IS EXPECTED TO
DECREASE DURING THE NEXT FEW DAYS. ALL OF THE INTENSITY GUIDANCE
FORECAST THE SYSTEM TO DISSIPATE DURING THE NEXT TWO TO THREE
DAYS...AND THE INTENSITY FORECAST FOLLOWS THIS SCENARIO. THE NEW
INTENSITY FORECAST IS UNCHANGED FROM THE PREVIOUS FORECAST.

FORECAST POSITIONS AND MAX WINDS

INIT 21/1500Z 33.8N 70.6W 35 KT 40 MPH
12H 22/0000Z 35.0N 69.0W 30 KT 35 MPH
24H 22/1200Z 36.8N 66.1W 30 KT 35 MPH
36H 23/0000Z 38.6N 62.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 23/1200Z...DISSIPATED

$$
FORECASTER BEVEN

[artist]

000
WTNT22 KNHC 211438
TCMAT2

TROPICAL STORM BRET FORECAST/ADVISORY NUMBER 16
NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011
1500 UTC THU JUL 21 2011

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 33.8N 70.6W AT 21/1500Z
POSITION ACCURATE WITHIN 20 NM

PRESENT MOVEMENT TOWARD THE NORTHEAST OR 55 DEGREES AT 8 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1007 MB
MAX SUSTAINED WINDS 35 KT WITH GUSTS TO 45 KT.
34 KT....... 45NE 60SE 45SW 0NW.
12 FT SEAS.. 30NE 50SE 0SW 0NW.
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 33.8N 70.6W AT 21/1500Z
AT 21/1200Z CENTER WAS LOCATED NEAR 33.5N 71.1W

FORECAST VALID 22/0000Z 35.0N 69.0W
MAX WIND 30 KT...GUSTS 40 KT.

FORECAST VALID 22/1200Z 36.8N 66.1W
MAX WIND 30 KT...GUSTS 40 KT.

FORECAST VALID 23/0000Z 38.6N 62.1W...POST-TROP/REMNT LOW
MAX WIND 25 KT...GUSTS 35 KT.

FORECAST VALID 23/1200Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 33.8N 70.6W

NEXT ADVISORY AT 21/2100Z

$$
FORECASTER BEVEN

[HURAKAN]

21/1745 UTC 33.7N 70.2W T2.0/2.0 BRET

30 knots

[HURAKAN]

AL, 02, 2011072118, , BEST, 0, 339N, 702W, 35, 1007, TS

no change

[cycloneye]

TROPICAL STORM BRET DISCUSSION NUMBER 17
NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011
500 PM AST THU JUL 21 2011

THE CENTER OF BRET REMAINS EXPOSED TO THE NORTHEAST OF A PERSISTENT
CLUSTER OF CONVECTION. AN ASCAT OVERPASS AT 1500 UTC SHOWED AN
AREA OF 30-35 KT WINDS SOUTHEAST OF THE CENTER. BASED ON THIS AND
THE RELATIVELY UNCHANGED APPEARANCE OF THE CYCLONE OVER THE PAST
FEW HOURS...THE INITIAL INTENSITY REMAINS 35 KT. ANALYSES FROM THE
SHIPS MODEL AND FROM CIMSS AT THE UNIVERSITY OF WISCONSIN INDICATE
THAT THE NORTHEASTERLY VERTICAL WIND SHEAR HAS INCREASED TO
35-40 KT...AND THIS IS ADVECTING MID/UPPER-LEVEL DRY AIR INTO THE
CYCLONE. ALL OF THE GLOBAL MODELS SHOW BRET WEAKENING TO A TROUGH
IN 48 HR OR LESS...AND THEREFORE THE INTENSITY FORECAST FOLLOWS
SUIT. THE NEW INTENSITY FORECAST IS UNCHANGED FROM THE PREVIOUS
ADVISORY.

THE INITIAL MOTION IS A LITTLE MORE TO THE RIGHT AT 060/9. OTHER
THAN THAT...THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS TRACK
FORECAST REASONING. BRET SHOULD MOVE GENERALLY NORTHEASTWARD TO
EAST-NORTHEASTWARD IN THE FLOW ON THE NORTH SIDE OF THE SUBTROPICAL
RIDGE UNTIL IT DISSIPATES...WITH A GRADUAL INCREASE IN FORWARD
SPEED DURING THAT TIME. THE NEW FORECAST TRACK IS SIMILAR TO...BUT
A LITTLE TO THE RIGHT OF...THE PREVIOUS ADVISORY FORECAST.

FORECAST POSITIONS AND MAX WINDS

INIT 21/2100Z 34.2N 69.7W 35 KT 40 MPH
12H 22/0600Z 35.5N 67.3W 30 KT 35 MPH
24H 22/1800Z 37.3N 63.8W 25 KT 30 MPH
36H 23/0600Z 39.0N 59.4W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 23/1800Z...DISSIPATED

$$
FORECASTER BEVEN

[somethingfunny]

The last gasp of convection just detatched from the center. On the loop you can really see the center speeding away from that convection -- I'd kill Bret on the 11PM advisory.

[KWT]

I suspect we are very close now to TD Bret, suspect its going toget downgraded very soon based on the convection being just about gone.

[TropicalAnalystwx13]

I suspect we are very close now to TD Bret, suspect its going toget downgraded very soon based on the convection being just about gone.

Agreed...Just a naked swirl now...May not make it another 12 hours.

[Florida1118]

Thats just depressing...

[cycloneye]

00z Best Track

Downgraded to TD.

AL, 02, 2011072200, , BEST, 0, 351N, 689W, 30, 1008, TD