Tropical Storm Bret

[Somerset Squall]

Invest 98L has become Tropical Depression 02L according to RECON investigating the system, located off the east coast of Florida.

invest_RENUMBER_al982011_al022011

Models are in fair agreement for slow motion of 02L over the next day or so followed by a northeasterly motion. Conditions appear conducive for some modest intensification at the least.

Edited July 17, 2011 by Somerset Squall

[Somerset Squall]

RECON are finding winds of TS strength, so 02L may become a tropical storm by next advisory. I think this system has caught many out with how fast it has formed, NHC included as the last TWO before first advisory only had the system at 40% risk of TC formation.

Edited July 17, 2011 by Somerset Squall

[Paranoid]

We've now got TS Bret. Was rather quick to form this one, given it was only 30% earlier today.

000

WTNT32 KNHC 172352

TCPAT2

BULLETIN

TROPICAL STORM BRET INTERMEDIATE ADVISORY NUMBER 1A

NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011

800 PM EDT SUN JUL 17 2011

...TROPICAL DEPRESSION STRENGTHENS...BECOMES THE SECOND TROPICAL

STORM OF THE 2011 ATLANTIC HURRICANE SEASON...

SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION

----------------------------------------------

LOCATION...27.5N 78.1W

ABOUT 100 MI...165 KM NW OF GREAT ABACO ISLAND

MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H

PRESENT MOVEMENT...SSE OR 145 DEGREES AT 2 MPH...4 KM/H

MINIMUM CENTRAL PRESSURE...1009 MB...29.80 INCHES

WATCHES AND WARNINGS

--------------------

CHANGES WITH THIS ADVISORY...

NONE

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WATCH IS IN EFFECT FOR...

* GRAND BAHAMA ISLAND AND THE ABACO ISLANDS IN THE NORTHWEST BAHAMAS

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR

PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.

DISCUSSION AND 48-HOUR OUTLOOK

------------------------------

AT 800 PM EDT...0000 UTC...THE CENTER OF TROPICAL STORM BRET WAS

LOCATED NEAR LATITUDE 27.5 NORTH...LONGITUDE 78.1 WEST. BRET IS

DRIFTING TOWARD THE SOUTH-SOUTHEAST NEAR 2 MPH...4 KM/H...AND

LITTLE MOVEMENT IS EXPECTED OVERNIGHT...FOLLOWED BY A SLOW NORTH-

NORTHEASTWARD MOTION ON MONDAY.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 40 MPH...65 KM/H...

WITH HIGHER GUSTS. SOME ADDITIONAL STRENGTHENING IS FORECAST

DURING THE NEXT 48 HOURS.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 35 MILES...55 KM...

FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB...29.80 INCHES.

HAZARDS AFFECTING LAND

----------------------

RAINFALL...BRET COULD PRODUCE TOTAL RAINFALL AMOUNTS OF 1

TO 3 INCHES OVER THE NORTHWEST BAHAMAS.

WIND...TROPICAL STORM CONDITIONS ARE POSSIBLE IN THE EXTREME

NORTHWESTERN BAHAMAS TONIGHT AND MONDAY.

SURF...LOCALLY HIGH SURF CONDITIONS CAN BE EXPECTED ALONG NORTHERN

AND WESTERN FACING BEACHES IN THE NORTHWEST BAHAMAS THROUGH

TONIGHT.

NEXT ADVISORY

-------------

NEXT COMPLETE ADVISORY...1100 PM EDT.

$$

FORECASTER BROWN/BERG

[Alex95]

Am I under the right impression when I say that this storm will drift NE this week, therefore not affecting the US? I'm travelling to Florida on Thursday, so I'm hoping I'm right!

[Alex95]

It has now been upgraded to a tropical storm - the thread should be renamed to Tropical Storm Bret. The US Mainland shouldn't be affected, just the Bahamas and maybe Bermuda later.

Edited July 18, 2011 by alza

[knocker]

The NAM at 1800z it then has it dissipating and as you said moving NE.

[Somerset Squall]

After drifting south towards the Bahamas, Bret has began the turn to the northeast as the steering currents become more defined between a building ridge to the southeast and an advancing trough to the northwest. This motion should continue over the coming days, gradually taking Bret towards colder water and higher shear associated with upper level westerlies common at higher lattitude. Until then, Bret is in a marginal environment for strengthening. Bret's current intensity is 45kts, and with shear being low and waters warm, some modest intensification is likely. Negative factors include dry air to the west of Bret, along with poor outflow to the northwest (reminds me of the environment Typhoon Ma-on is experiencing), which should cap any major intensification. NHC are forecasting a peak of 55kts which seems fair given the environment.

[Cookie]

[Paranoid]

Now up to 65mph. Is that an eye-like feature in the latest image or just a gap in the convection?

000

WTNT32 KNHC 182056

TCPAT2

BULLETIN

TROPICAL STORM BRET ADVISORY NUMBER 5

NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011

500 PM EDT MON JUL 18 2011

...BRET STRENGTHENS AS IT HEADS AWAY FROM THE BAHAMAS...

SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION

----------------------------------------------

LOCATION...28.3N 77.0W

ABOUT 130 MI...210 KM N OF GREAT ABACO ISLAND

MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H

PRESENT MOVEMENT...NNE OR 30 DEGREES AT 7 MPH...11 KM/H

MINIMUM CENTRAL PRESSURE...996 MB...29.41 INCHES

WATCHES AND WARNINGS

--------------------

CHANGES WITH THIS ADVISORY...

THE GOVERNMENT OF THE BAHAMAS HAS DISCONTINUED THE TROPICAL STORM

WARNINGS FOR GRAND BAHAMA ISLAND AND THE ABACO ISLANDS.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

NONE.

DISCUSSION AND 48-HOUR OUTLOOK

------------------------------

AT 500 PM EDT...2100 UTC...THE CENTER OF TROPICAL STORM BRET WAS

LOCATED NEAR LATITUDE 28.3 NORTH...LONGITUDE 77.0 WEST. BRET IS

MOVING TOWARD THE NORTH-NORTHEAST NEAR 7 MPH...11 KM/H...AND A TURN

TOWARD THE NORTHEAST WITH AN INCREASE IN FORWARD SPEED IS EXPECTED

OVER THE NEXT 48 HOURS.

OBSERVATIONS FROM AN AIR FORCE RESERVE UNIT HURRICANE HUNTER

AIRCRAFT INDICATE THAT THE MAXIMUM SUSTAINED WINDS HAVE INCREASED

TO NEAR 65 MPH...100 KM/H...WITH HIGHER GUSTS. SOME ADDITIONAL

STRENGTHENING IS POSSIBLE OVERNIGHT...AND BRET COULD APPROACH

HURRICANE STRENGTH BY EARLY TUESDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 50 MILES...85 KM

FROM THE CENTER.

THE MINIMUM CENTRAL PRESSURE ESTIMATED FROM HURRICANE HUNTER DATA IS

996 MB...29.41 INCHES.

HAZARDS AFFECTING LAND

----------------------

RAINFALL...BRET COULD PRODUCE TOTAL RAINFALL AMOUNTS OF 2 TO 4

INCHES OVER THE NORTHWEST BAHAMAS. THESE RAINS WILL DIMINISH

TONIGHT.

SURF...LOCALLY HIGH SURF CONDITIONS ALONG THE NORTHERN AND WESTERN

FACING BEACHES IN THE NORTHWEST BAHAMAS WILL DECREASE TONIGHT.

NEXT ADVISORY

-------------

NEXT COMPLETE ADVISORY...1100 PM EDT.

$$

FORECASTER PASCH

[Cookie]

[Somerset Squall]

Bret has continued to strengthen and intensity is now at 55kts. Bret has a better chance of briefly becoming a hurricane before shear increases in about 18hrs time. Bret has certainly been trying to develop an eye in the last few hours, and overall the convection looks deeper than 6 hours ago. Track forecast remains the same and the northeasterly motion should continue.

[knocker]

WTNT42 KNHC 190839

TCDAT2

TROPICAL STORM BRET DISCUSSION NUMBER 7

NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011

500 AM EDT TUE JUL 19 2011

DEEP CONVECTION HAS ALL BUT DISAPPEARED NEAR THE CENTER OF BRET IN

THE PAST FEW HOURS...LIKELY DUE TO THE ENTRAINMENT OF DRY AIR INTO

THE CYCLONE CORE AS SEEN IN SATELLITE IMAGERY AND DEWPOINT DATA

FROM THE AIR FORCE RESERVE UNIT HURRICANE HUNTER AIRCRAFT. THE

INITIAL INTENSITY IS LOWERED TO 45 KT BASED ON A 850-MB FLIGHT-

LEVEL WIND MAXIMUM OF 55 KT AND A PEAK SFMR WIND OF 43 KT. THE

DRIER ENVIRONMENT AND A FORECAST OF INCREASING VERTICAL WIND SHEAR

ARE NOT FAVORABLE FOR RESTRENGTHENING...AND THE INTENSITY GUIDANCE

SHOWS BRET SLOWLY WEAKENING FROM THIS POINT FORWARD. THE NEW NHC

FORECAST FOLLOWS THIS REASONING AND SHOWS LITTLE CHANGE THROUGH 12

HOURS FOLLOWED BY GRADUAL WEAKENING UNTIL DISSIPATION IN ABOUT 96

HOURS...IN BEST AGREEMENT WITH THE LGEM. HOWEVER...IF DEEP

CONVECTION DOES NOT RETURN...BRET COULD WEAKEN AND DISSIPATE MORE

QUICKLY THAN INDICATED HERE.

AIRCRAFT FIXES SUGGEST THAT THE LONG-TERM INITIAL MOTION IS TOWARD

THE NORTH-NORTHEAST OR 025 DEGREES AT AROUND 6 KT...A LITTLE TO THE

LEFT OF THE PREVIOUS FORECAST TRACK. OVERALL...THE TRACK FORECAST

REASONING REMAINS UNCHANGED AS BRET WILL GRADUALLY ACCELERATE TOWARD

THE NORTHEAST OVER THE NEXT COUPLE OF DAYS AS A MID-LEVEL RIDGE

BUILDS TO THE SOUTHEAST OF THE CYCLONE. THROUGH 48 HOURS...THE

GUIDANCE IS TIGHTLY CLUSTERED AND THE NEW OFFICIAL FORECAST HAS

BEEN ADJUSTED A LITTLE TO THE LEFT OF THE PREVIOUS ONE TO ACCOUNT

FOR THE INITIAL POSITION AND MOTION. AT 72 HOURS A MORE SUBSTANTIAL

ADJUSTMENT WAS MADE...TO THE LEFT OF AND SLOWER THAN THE PREVIOUS

NHC FORECAST...TRENDING TOWARD THE NEW MULTI-MODEL CONSENSUS.

FORECAST POSITIONS AND MAX WINDS

INIT 19/0900Z 29.3N 76.4W 45 KT 50 MPH

12H 19/1800Z 30.0N 75.8W 45 KT 50 MPH

24H 20/0600Z 30.9N 74.8W 40 KT 45 MPH

36H 20/1800Z 32.1N 73.4W 35 KT 40 MPH

48H 21/0600Z 33.6N 71.9W 35 KT 40 MPH

72H 22/0600Z 36.5N 68.0W 30 KT 35 MPH

96H 23/0600Z...DISSIPATED

$$

FORECASTER BRENNAN

[Somerset Squall]

Shear has weakened Bret and the intensity of the storm didn't surpass 55kts. Intensity has fallen to 45kts, and NHC say this could be generous. Shear has stripped the convection from Bret's small LLC, and I don't think Bret will survive much longer because the storm's small size makes it particularly vunerable to even modest amounts of shear. Further weakening is likely.

[onlyME]

Today Bret has exposed center,but it maintained intensity at 45 kts.

Discussion

although Bret is only producing a small amount of deep convectionthis morning...data from the Air Force Reserve hurricane huntersindicate that the storm has not weakened yet. Flight-level winds...SFMR winds...and dropsonde data all suggest an initial intensityof 45 kt. Gradual weakening is still forecast as the atmosphericenvironment is expected to remain hostile with north-northeasterlyshear near 30 kt and rather dry mid-level air being entrained intothe cyclone. The NHC intensity forecast is unchanged from earlierand calls for Bret to dissipate by day 3...in agreement with mostof the guidance.

Aircraft and satellite fixes indicate that Bret has turned a bit tothe right during the past 6 to 12 hours...and the initial motionestimate is 050/06. A northeastward motion with a gradual increasein forward speed is forecast until dissipation. The track modelguidance is in good agreement...and the new official forecast isessentially an update of the previous one.

The 34-kt wind and 12-ft seas radii have been adjusted based onaircraft and altimeter data...respectively.

Forecast positions and Max winds

init 20/0900z 31.1n 74.4w 45 kt 50 mph 12h 20/1800z 31.9n 73.4w 40 kt 45 mph 24h 21/0600z 33.2n 71.9w 40 kt 45 mph 36h 21/1800z 34.6n 70.2w 35 kt 40 mph 48h 22/0600z 36.2n 68.0w 30 kt 35 mph 72h 23/0600z...dissipated

[Cookie]

going going

[Somerset Squall]

Bret continues to be sheared but is putting up a good fight. Intensity has fallen slightly to 40kts. Convection clings to the south side of the LLC, but because the LLC has been partially exposed for some time now, it is looking less defined and is slowly winding down.

[onlyME]

Bret is fighting with wind shear and dry air and its intensity has fallen to 35 kts.

Discussion from NHC ->

Statement as of 11:00 am AST on July 21, 2011

While Bret continues to generate a strong convective cluster southof the exposed low-level center...the system is gradually losingorganization as it remains affected by northerly vertical windshear. There is no recent data from near the center. However...tropical-storm winds could still be occurring in and near theconvection based on a 1-minute wind of 33 kt recently observed atbuoy 41048. Thus...the initial intensity remains a possiblygenerous 35 kt.

The initial motion is 055/8. There is no significant change to theprevious forecast track or reasoning. Bret should movenortheastward in the flow on the north side of the subtropicalridge until it dissipates...with a gradual increase in forwardspeed during that time. The new forecast track is similar to theprevious advisory.

Bret is moving through an area of mid/upper-level dry air...and itis expected to encounter gradually decreasing sea surfacetemperatures along the forecast track. This combination is likelyto cause the cyclone to weaken even though the shear is expected todecrease during the next few days. All of the intensity guidanceforecast the system to dissipate during the next two to threedays...and the intensity forecast follows this scenario. The newintensity 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

Satellite image ->

[Somerset Squall]

Convection has completely dissipated in association with Bret, and the system has been declared a remnant low. Regeneration is not expected due to continued shear and dry air.

[Cookie]

Another one bites the dust!