WTNT45 KNHC 261512
TCDAT5
TROPICAL STORM DANNY DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
1100 AM EDT WED AUG 26 2009
 
SATELLITE IMAGERY SHOWS THAT THE AREA OF DISTURBED WEATHER EAST OF
THE BAHAMAS HAS DEVELOPED A WELL-DEFINED LOW-LEVEL CIRCULATION...
WITH REPORTS FROM A NOAA HURRICANE HUNTER AIRCRAFT INDICATING THE
SYSTEM WAS BEST DEVELOPED BELOW 12000 FT.  QUIKSCAT DATA AND A FEW
OBSERVATIONS FROM THE STEPPED FREQUENCY MICROWAVE RADIOMETER SHOW
TROPICAL STORM-FORCE WINDS OCCURRING NORTH AND NORTHEAST OF THE
CENTER...WHICH IS THE BASIS FOR THE INITIAL INTENSITY OF 40 KT. 
THE STORM HAS BEEN TANGLED UP WITH AN UPPER-LEVEL LOW FOR THE PAST
24 HR...AND THE STRUCTURE AS MUCH RESEMBLES A SUBTROPICAL CYCLONE
AS A TROPICAL CYCLONE.  HOWEVER...CYCLONE PHASE ANALYSES FROM
FLORIDA STATE UNIVERSITY SUGGEST THAT DANNY IS MARGINALLY MORE
TROPICAL THAN SUBTROPICAL...HENCE THE DESIGNATION OF TROPICAL
STORM.

THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 295/16.  DANNY IS ON THE
NORTH SIDE OF A MID/UPPER-LEVEL LOW CENTERED OVER HISPANIOLA AND
SOUTHWEST OF A MID/UPPER-LEVEL RIDGE CENTER EAST OF BERMUDA.
THIS PATTERN SHOULD STEER DANNY GENERALLY NORTHWESTWARD WITH
DECELERATION FOR THE NEXT 24-36 HR.  AFTER THAT...THE LARGE SCALE
MODELS AGREE THAT A MID/UPPER-LEVEL TROUGH SHOULD DEVELOP OVER THE
GREAT LAKES...WITH A MID/UPPER-LEVEL LOW OVER THE GULF COAST STATES
MOVING EASTWARD OR NORTHEASTWARD.  THIS EVOLUTION SHOULD CAUSE
DANNY TO TURN NORTHWARD AND THEN RECURVE INTO THE WESTERLIES. 
WHILE THE MODELS AGREE ON THE SCENARIO...THERE IS ENOUGH SPREAD IN
THE TRACK GUIDANCE TO MAKE IT UNCERTAIN WHAT LAND AREA DANNY MAY
AFFECT.  THE NAM AND THE CANADIAN MODELS FORECAST DANNY TO MAKE
LANDFALL IN EASTERN NORTH CAROLINA IN ABOUT 72 HR AND MOVE UP THE
U. S. EASTERN SEABOARD...WHILE THE GFS...HWRF... AND GFDL SHOW A
MORE EASTERLY TRACK THAT KEEPS DANNY OFFSHORE UNTIL IT REACHES THE
CANADIAN MARITIMES.  THE FORECAST SPLITS THE DIFFERENCE BETWEEN
THESE EXTREMES AND IS A LITTLE TO THE LEFT OF THE MODEL CONSENSUS.
THE FORECAST TRACK IS ROUGHLY PARALLEL TO THE U. S. EAST COAST...AND
ANY DEVIATION FROM THE TRACK COULD MAKE A LARGE DIFFERENCE IN WHAT
AREAS GET IMPACTED BY DANNY.  THEREFORE...IT IS IMPORTANT NOT TO
FOCUS TOO MUCH ON THE EXACT FORECAST TRACK.
 
THE INTENSITY FORECAST IS PROBLEMATIC.  WATER VAPOR IMAGERY SHOWS
UPPER-LEVEL LOWS NORTH AND SOUTH OF DANNY CONNECTED BY A CYCLONIC
SHEAR AXIS.  THIS IS NOT A IDEAL PATTERN FOR STRENGTHENING...AND
THE LARGE-SCALE MODELS SUGGEST IT MAY TAKE 24-36 HR FOR THE
ENVIRONMENT TO BECOME MORE FAVORABLE.  BASED ON THIS AND THE
CURRENT ORGANIZATION OF THE STORM...THE INTENSITY FORECAST CALLS
FOR SLOW STRENGTHENING FOR THE FIRST 36 HR.  IT THEN SHOWS A FASTER
STRENGTHENING FROM 36-48 HR AS CONDITIONS BECOME MORE FAVORABLE. 
AFTER 48 HR...STRONG UPPER-LEVEL SOUTHWESTERLY WINDS ASSOCIATED
WITH THE EASTERN U. S. TROUGHS ARE EXPECTED TO CAUSE INCREASED
SHEAR AND THE BEGINNING OF EXTRATROPICAL TRANSITION.  THE INTENSITY
FORECAST THUS CALLS FOR DANNY TO REACH 65 KT IN 72 HR...THEN BECOME
EXTRATROPICAL BY 96 HR.  THE INTENSITY FORECAST IS IN BEST
AGREEMENT WITH THE SHIPS AND LGEM MODELS.  HOWEVER...IT IS WEAKER
THAN THE FORECASTS OF THE GFDL AND HWRF.


FORECAST POSITIONS AND MAX WINDS
 
INITIAL      26/1500Z 24.9N  70.3W    40 KT
 12HR VT     27/0000Z 25.8N  72.0W    40 KT
 24HR VT     27/1200Z 26.8N  73.6W    45 KT
 36HR VT     28/0000Z 28.1N  74.5W    50 KT
 48HR VT     28/1200Z 30.1N  75.2W    60 KT
 72HR VT     29/1200Z 36.0N  73.5W    65 KT
 96HR VT     30/1200Z 45.0N  67.0W    65 KT...EXTRATROPICAL
120HR VT     31/1200Z 52.0N  53.0W    60 KT...EXTRATROPICAL
 
$$
FORECASTER BEVEN
 

WTNT45 KNHC 262035
TCDAT5
TROPICAL STORM DANNY DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
500 PM EDT WED AUG 26 2009
 
SATELLITE IMAGERY AND REPORTS FROM AN AIR FORCE RESERVE HURRICANE
HUNTER AIRCRAFT INDICATE THAT DANNY IS VERY DISORGANIZED AT THIS
TIME.  THERE IS NO ORGANIZED CONVECTION NEAR THE CENTER...AND THE
STRONGEST WINDS ARE IN A BAND 100-150 N MI FROM THE CENTER OVER THE
NORTHERN SEMICIRCLE.  THE AIRCRAFT REPORTED 1500 FT FLIGHT-LEVEL
WINDS OF 49 KT AND ESTIMATED SURFACE WINDS OF 40-45 KT FROM THE
SFMR.  BASED ON THIS...THE INITIAL INTENSITY REMAINS 40 KT.  THE
AIRCRAFT JUST REPORTED A CENTRAL PRESSURE OF 1007 MB.
 
THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 300/10...UNCERTAIN
BECAUSE THE STORM SEEMS TO BE DECELERATING...AND THE CENTER MAY BE
OCCASIONALLY RE-FORMING DUE TO CONVECTIVE BURSTS.  THERE IS NO
CHANGE TO THE PREVIOUS FORECAST REASONING.  DANNY IS NORTH OF A
MID/UPPER-LEVEL LOW CENTERED OVER HISPANIOLA AND SOUTHWEST OF A
MID/UPPER-LEVEL RIDGE CENTER EAST OF BERMUDA.  THIS PATTERN SHOULD
STEER DANNY GENERALLY NORTHWESTWARD FOR THE NEXT 24 HR OR SO. 
AFTER THAT...A MID/UPPER-LEVEL TROUGH SHOULD DEVELOP OVER THE GREAT
LAKES...WITH A MID/UPPER-LEVEL LOW OVER THE GULF COAST STATES
MOVING EASTWARD OR NORTHEASTWARD.  THIS EVOLUTION SHOULD CAUSE
DANNY TO TURN NORTHWARD AND THEN RECURVE INTO THE WESTERLIES. 
WHILE THE MODELS AGREE ON THE SCENARIO...THERE IS STILL SIGNIFICANT
UNCERTAINTY AS TO WHAT LAND AREA DANNY MAY AFFECT.  THE ECMWF...
UKMET...AND CANADIAN MODELS FORECAST THE CENTER TO PASS NEAR CAPE
HATTERAS AND THEN MAKE LANDFALL IN NEW ENGLAND.  THE GFS AND GFDL
SHOW THE CENTER PASSING EAST OF HATTERAS AND THEN PASSING NEAR OR
OVER CAPE COD.  THE HWRF AND NOGAPS...AS WELL AS THE CORRECTED
CONSENSUS MODELS...SHOW THE CENTER PASSING EAST OF CAPE COD AND
NEAR OR OVER NOVA SCOTIA.  OVERALL..THE GUIDANCE ENVELOPE HAS
SHIFTED SLIGHTLY TO THE EAST SINCE THE LAST ADVISORY.  THE NEW
FORECAST TRACK IS ALSO SHIFTED SLIGHTLY TO THE EAST AND LIES NEAR
THE MIDDLE OF THE GUIDANCE ENVELOPE.  THE FORECAST TRACK IS ROUGHLY
PARALLEL TO THE U. S. EAST COAST...AND ANY DEVIATION FROM THE TRACK
COULD MAKE A LARGE DIFFERENCE IN WHAT AREAS GET IMPACTED BY DANNY. 
THEREFORE...IT IS IMPORTANT NOT TO FOCUS TOO MUCH ON THE EXACT
FORECAST TRACK.
 
THE INTENSITY FORECAST REMAINS PROBLEMATIC.  WATER VAPOR IMAGERY
SHOWS UPPER-LEVEL LOWS NORTH AND SOUTH OF DANNY CONNECTED BY A
CYCLONIC SHEAR AXIS.  THIS IS NOT A IDEAL PATTERN FOR
STRENGTHENING...AND IT MAY TAKE 24 HR OR MORE FOR THE ENVIRONMENT
TO BECOME MORE FAVORABLE.  IN ADDITION...THE CURRENT STRUCTURE OF
THE STORM FAVORS SLOW STRENGTHENING AT BEST.  BASED ON THIS...THE
INTENSITY FORECAST CALLS FOR SLOW STRENGTHENING FOR THE FIRST
36 HR.  IT THEN SHOWS A FASTER STRENGTHENING FROM 36-48 HR AS
CONDITIONS BECOME MORE FAVORABLE.  AFTER 48 HR...STRONG UPPER-LEVEL
SOUTHWESTERLY WINDS ASSOCIATED WITH THE EASTERN U. S. TROUGHS ARE
EXPECTED TO CAUSE INCREASED SHEAR AND INITIATE EXTRATROPICAL
TRANSITION...WHICH COULD START BEFORE DANNY REACHES THE LATITUDE OF
NEW ENGLAND.  THE INTENSITY FORECAST CALLS FOR DANNY TO REACH 65 KT
IN 72 HR...THEN BECOME EXTRATROPICAL BY 96 HR.  THE INTENSITY
FORECAST IS IN BEST AGREEMENT WITH THE SHIPS AND LGEM MODELS. 
HOWEVER...IT REMAINS WEAKER THAN THE FORECASTS OF THE GFDL AND
HWRF.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      26/2100Z 25.2N  71.2W    40 KT
 12HR VT     27/0600Z 26.0N  72.5W    40 KT
 24HR VT     27/1800Z 27.1N  73.8W    45 KT
 36HR VT     28/0600Z 28.7N  74.5W    50 KT
 48HR VT     28/1800Z 31.1N  74.5W    60 KT
 72HR VT     29/1800Z 38.5N  71.5W    65 KT
 96HR VT     30/1800Z 47.5N  63.5W    60 KT...EXTRATROPICAL
120HR VT     31/1800Z 53.1N  48.0W    45 KT...EXTRATROPICAL
 
$$
FORECASTER BEVEN
 

WTNT45 KNHC 270246
TCDAT5
TROPICAL STORM DANNY DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
1100 PM EDT WED AUG 26 2009
 
AFTER THE AIR FORCE HURRICANE HUNTER AIRCRAFT LEFT DANNY EARLIER
THIS AFTERNOON...VISIBLE SATELLITE IMAGERY SEEMED TO SUGGEST THAT A
NEW LOW-LEVEL CENTER WAS FORMING FARTHER TO THE NORTHEAST CLOSER TO
THE DEEP CONVECTION.  THE OVERALL CIRCULATION REMAINS DISTORTED AND
LIKELY CONSISTS OF A BROAD CENTER WITH A SHARP SURFACE TROUGH
EXTENDING TO THE SOUTHWEST.  NONETHELESS...A NOAA HURRICANE HUNTER
AIRCRAFT CONDUCTING A RESEARCH MISSION THIS EVENING DID RELAY SOME
RELIABLE SFMR DATA WHICH SUGGESTED THAT THE MAXIMUM WINDS ARE NEAR
45 KT WITHIN THE DEEP CONVECTION ABOUT 100 N MI TO THE NORTHEAST OF
THE CENTER.  A DROPSONDE FROM THIS FLIGHT ALSO INDICATED THAT THE
MINIMUM PRESSURE HAS FALLEN TO NEAR 1006 MB.

THE INITIAL MOTION IS ESTIMATED AT 310/9...BUT THIS IS HIGHLY
UNCERTAIN SINCE THE CENTER APPEARS TO BE REFORMING.  THE FORECAST
TRACK REASONING HAS NOT CHANGED...AND THE MODELS ARE IN GOOD
AGREEMENT THROUGH 72 HOURS.  DANNY IS EXPECTED TO MOVE
NORTHWESTWARD AND THEN TURN NORTHWARD WITHIN 48 HOURS AS IT IS
STEERED BETWEEN THE SUBTROPICAL RIDGE AND A EASTWARD-MOVING
MID-LEVEL LOW CURRENTLY LOCATED OVER THE NORTHERN GULF COAST. 
THEREAFTER...DANNY IS EXPECTED TO ACCELERATE NORTH-NORTHEASTWARD...
PARALLELING THE MID-ATLANTIC AND NEW ENGLAND COASTS...AS IT BECOMES
EMBEDDED IN THE FLOW AHEAD OF A DEEPENING UPPER LEVEL TROUGH OVER
THE GREAT LAKES.  IT SHOULD STILL BE NOTED THAT ANY DEVIATION TO
THE LEFT OF THE FORECAST TRACK THROUGH 72 HOURS WOULD BRING DANNY
CLOSER TO THE U.S. EAST COAST.

ALL THE INTENSITY GUIDANCE CONTINUES TO STRENGTHEN DANNY...BUT IT IS
NOT CLEAR WHY THEY MAKE THE CYCLONE SO STRONG.  THE UPPER-LEVEL
ENVIRONMENT IS EXPECTED TO BE FAVORABLE FOR STRENGTHENING OVER THE
NEXT 36-48 HOURS...BUT THEN THE VERTICAL SHEAR IS FORECAST TO
INCREASE TO 40 KT...AND MUCH MORE...ONCE DANNY ACCELERATES TO THE
NORTH AND NORTHEAST.  THE SHIPS AND LGEM MODELS MYSTERIOUSLY SHOW
THE SYSTEM STRENGTHENING TO 70-75 KT ONCE THE SHEAR INCREASES. 
SINCE THIS DOES NOT SEEM VERY REALISTIC...THE OFFICIAL FORECAST
LIMITS THE INTENSITY AT 65 KT.  ALTHOUGH THE OFFICIAL FORECAST
KEEPS DANNY AS A TROPICAL CYCLONE THROUGH 72 HOURS...THE GLOBAL
MODEL FIELDS AND FSU CYCLONE PHASE SPACE DIAGRAMS SUGGEST THAT
DANNY COULD BE EXTRATROPICAL BY THE TIME IT IS NEAR THE NEW ENGLAND
COAST. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      27/0300Z 26.0N  71.6W    45 KT
 12HR VT     27/1200Z 26.8N  72.7W    45 KT
 24HR VT     28/0000Z 28.1N  74.0W    50 KT
 36HR VT     28/1200Z 30.0N  74.6W    55 KT
 48HR VT     29/0000Z 32.8N  74.2W    65 KT
 72HR VT     30/0000Z 41.5N  69.5W    65 KT
 96HR VT     31/0000Z 49.0N  58.5W    55 KT...EXTRATROPICAL
120HR VT     01/0000Z 53.5N  43.0W    40 KT...EXTRATROPICAL
 
$$
FORECASTER BERG/PASCH
 

WTNT45 KNHC 270841
TCDAT5
TROPICAL STORM DANNY DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
500 AM EDT THU AUG 27 2009
 
DATA FROM NOAA BUOY 41047 AND THE AIR FORCE RECONNAISSANCE AIRCRAFT
HAVE BEEN CRITICAL IN LOCATING THE BROAD AND ELONGATED CIRCULATION
OF DANNY THIS MORNING...WHICH APPEARS TO HAVE MADE ANOTHER
NORTHWARD REFORMATION. THE AIR FORCE PLANE FOUND 55 KT WINDS AT 850
MB AND DROPSONDE AND RELIABLE SFMR WINDS OF ABOUT 45 KT. AN EARLIER
NOAA HURRICANE HUNTER AIRCRAFT SHOWED 12000 FT WINDS OF 66 KT AND
RELIABLE SFMR VALUES OF 45-50 KT. THE NOAA SFMR DATA ALSO
REASONABLY FIT A 2254 UTC QUIKSCAT PASS WHICH HAD A FEW 50 KT WIND
BARBS. THEREFORE...THE ADVISORY INTENSITY IS SET TO 50 KT. IT
SHOULD BE NOTED THAT DANNY DOES NOT HAVE A TYPICAL TROPICAL CYCLONE
STRUCTURE AND HAS MOST OF THE STRONG WINDS LOCATED WELL NORTH AND
EAST OF THE CENTER.
 
WITH ALL THE CENTER REFORMATIONS...THE INITIAL MOTION IS JUST ABOUT
IMPOSSIBLE TO DETERMINE...BUT THE BEST ESTIMATE IS 315/9. DESPITE
THE INITIAL UNCERTAINTY...THE MODELS ARE IN EXCELLENT AGREEMENT ON
A TURN TOWARD THE NORTH ON FRIDAY AS DANNY MOVES BETWEEN A RIDGE
OVER THE WESTERN ATLANTIC OCEAN AND A SHORTWAVE TROUGH OVER THE
SOUTHEASTERN UNITED STATES. THE STORM SHOULD THEN ACCELERATE
NORTHEASTWARD DUE TO INCREASING FLOW AHEAD OF A LARGER TROUGH OVER
THE GREAT LAKES. THE OFFICIAL FORECAST IS SHIFTED EASTWARD BECAUSE
OF THE CENTER REFORMATION AND THE GOOD TRACK MODEL AGREEMENT.
HOWEVER...ANY SIGNIFICANT DEVIATION TO THE WEST OF THE FORECAST
TRACK WOULD BRING DANNY CLOSER TO THE U.S. EAST COAST.  
 
WHILE SHEAR IS RELATIVELY LIGHT NEAR DANNY FOR THE TIME BEING...
GLOBAL MODELS INCREASE THE SHEAR WITHIN A DAY OR SO. DESPITE THIS
PATTERN CHANGE...ALL OF THE RELIABLE INTENSITY MODELS MAKE DANNY A
HURRICANE IN A COUPLE OF DAYS...AND MOST OF THE GLOBAL MODELS SHOW
THE SYSTEM INTENSIFYING DESPITE THE SHEAR. SOME OF THIS INCREASE IN
STRENGTH COULD BE DUE TO BAROCLINIC INFLUENCES AS THE GLOBAL MODELS
ARE SHOWING A RATHER DIFFLUENT PATTERN NEAR THE TROPICAL CYCLONE
WITH STRONG JET DYNAMICS. HOWEVER...THIS WOULD ARGUE MORE FOR A
STRONG EXTRATROPICAL CYCLONE RATHER THAN A TROPICAL CYCLONE. THE
OFFICIAL FORECAST STILL SHOWS THIS SYSTEM TO BE A HURRICANE IN A
COUPLE OF DAYS BUT GIVEN THE SEEMINGLY UNFAVORABLE ENVIRONMENT...
THE NHC FORECAST IS LOWER THAN MOST OF THE GUIDANCE AND MAKES DANNY
EXTRATROPICAL BY 72 HOURS.

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      27/0900Z 27.4N  72.1W    50 KT
 12HR VT     27/1800Z 28.4N  73.1W    50 KT
 24HR VT     28/0600Z 30.0N  74.0W    55 KT
 36HR VT     28/1800Z 32.3N  74.0W    60 KT
 48HR VT     29/0600Z 35.7N  72.9W    65 KT
 72HR VT     30/0600Z 44.0N  66.5W    65 KT...EXTRATROPICAL
 96HR VT     31/0600Z 50.0N  55.0W    50 KT...EXTRATROPICAL
120HR VT     01/0600Z 53.0N  40.0W    35 KT...EXTRATROPICAL
 
$$
FORECASTER BLAKE
 

WTNT45 KNHC 271449
TCDAT5
TROPICAL STORM DANNY DISCUSSION NUMBER   5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
1100 AM EDT THU AUG 27 2009
 
DANNY HAS BECOME A LITTLE BETTER ORGANIZED THIS MORNING.  THE
LOW-LEVEL CIRCULATION LOOKS BETTER DEFINED THAN IT DID YESTERDAY...
AND THE CONVECTION IS CLOSER TO THE CENTER.  THAT BEING SAID...THE
CENTER IS STILL EXPOSED...THE CONVECTION HAS MORE OF A LINEAR
CHARACTER THAN THE CURVED BANDS CHARACTERISTIC OF A TROPICAL
CYCLONE...AND THE STRONGEST WINDS ARE STILL WELL REMOVED FROM THE
CENTER.  THE INITIAL INTENSITY IS HELD AT 50 KT PENDING THE NEXT
AIR FORCE RESERVE HURRICANE HUNTER MISSION AT 18Z...ALTHOUGH RECENT
QUIKSCAT DATA SUGGESTS THIS COULD BE A LITTLE GENEROUS.
 
THE EXPOSED LOW-LEVEL CENTER HAS BEEN MOVING ALMOST DUE WESTWARD FOR
THE PAST FEW HOURS.  IT IS UNCLEAR IF THIS IS REPRESENTATIVE OF THE
ACTUAL MOTION OF DANNY OR A SHORT-TERM TREND.  SO...THE INITIAL
MOTION IS AN UNCERTAIN 310/11.  DESPITE THE PROBLEMATIC INITIAL
MOTION...THE TRACK GUIDANCE MODELS ARE IN EXCELLENT AGREEMENT THAT
DANNY SHOULD TURN NORTHWARD OVER THE NEXT 24-36 HR IN ADVANCE OF A
COMPLEX DEEP-LAYER TROUGH MOVING INTO THE EASTERN UNITED STATES.
AFTER THAT...THE STORM SHOULD ACCELERATE NORTHEASTWARD INTO THE
WESTERLIES...PASSING NEAR OR OVER NEW ENGLAND AND THE CANADIAN
MARITIMES ON ITS WAY INTO THE NORTH ATLANTIC.  THE
NAM...NOGAPS...AND CANADIAN MODELS ARE ON THE LEFT SIDE OF THE
GUIDANCE ENVELOPE... CALLING FOR THE CENTER TO PASS NEAR CAPE
HATTERAS AND THEN OVER NEW ENGLAND.  THE GFS...GFDL...AND HWRF ARE
ON THE RIGHT SIDE...CALLING FOR THE CENTER TO STAY OFFSHORE UNTIL
IT REACHES NOVA SCOTIA.  THE NEW FORECAST TRACK IS ADJUSTED TO THE
LEFT OF THE PREVIOUS TRACK FOR THE FIRST 48 HR BASED ON THE INITIAL
POSITION AND MOTION...AND IT LIES DOWN THE MIDDLE OF THE GUIDANCE
ENVELOPE.  WHILE THE FORECAST TRACK DOES NOT CURRENTLY SHOW DANNY
MAKING LANDFALL IN THE UNITED STATES...ADDITIONAL MOTION TO THE
LEFT OF THE TRACK COULD BRING THE CENTER NEAR OR OVER THE U. S.
EASTERN SEABOARD.
 
DANNY IS CURRENTLY IN AN AREA OF UPPER-LEVEL CONFLUENT FLOW
ASSOCIATED WITH THE PERSISTENT CYCLONIC SHEAR AXIS SEEN IN WATER
VAPOR IMAGERY.  THE LARGE-SCALE MODELS FORECAST THIS FEATURE TO BE
REPLACED BY AN UPPER-LEVEL ANTICYCLONE DURING THE NEXT 24-30 HR...
AND IF THIS VERIFIES IT WILL GIVE DANNY ITS BEST CHANCE TO
STRENGTHEN.  BASED ON THIS...THE INTENSITY FORECAST CALLS FOR DANNY
TO STRENGTHEN DURING THE 24-48 HR PERIOD...WITH A PEAK INTENSITY OF
65 KT.  THE GUIDANCE AGREES THAT DANNY SHOULD START LOSING TROPICAL
CHARACTERISTICS AND INTENSITY AFTER 48 HR AS IT BECOMES EMBEDDED IN
A STRONG BAROCLINIC ENVIRONMENT.  OVERALL...THE INTENSITY FORECAST
IS IN BEST AGREEMENT WITH THE INTENSITY CONSENSUS...WITH THE PEAK
INTENSITY BELOW THAT OF THE HWRF AND GFDL MODELS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      27/1500Z 27.5N  73.1W    50 KT
 12HR VT     28/0000Z 28.7N  73.9W    50 KT
 24HR VT     28/1200Z 30.3N  74.5W    55 KT
 36HR VT     29/0000Z 33.2N  74.3W    60 KT
 48HR VT     29/1200Z 36.9N  72.4W    65 KT
 72HR VT     30/1200Z 45.0N  64.5W    60 KT...EXTRATROPICAL
 96HR VT     31/1200Z 50.0N  53.0W    45 KT...EXTRATROPICAL
120HR VT     01/1200Z 52.5N  37.0W    30 KT...EXTRATROPICAL
 
$$
FORECASTER BEVEN
 

WTNT45 KNHC 272038
TCDAT5
TROPICAL STORM DANNY DISCUSSION NUMBER   6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
500 PM EDT THU AUG 27 2009
 
REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE
THAT THE CIRCULATION OF DANNY HAS BECOME BETTER DEFINED TODAY...
WITH STRONGER WINDS IN THE PREVIOUSLY WEAK SOUTHWESTERN QUADRANT. 
ASIDE FROM THAT...THE CYCLONE REMAINS VERY DISORGANIZED.  THE MAIN
CONVECTION IS IN A LINE 130-170 N MI EAST THROUGH SOUTH OF THE
CENTER...AND THE STRONGEST WINDS ARE 100 N MI OR MORE FROM THE
CENTER OVER THE NORTHERN SEMICIRCLE.  THE AIRCRAFT DATA...AS WELL
AS DATA FROM THE QUIKSCAT AND ASCAT SCATTEROMETERS...SUGGEST THAT
THE MAXIMUM WINDS HAVE DECREASED TO 40-45 KT.  THE INITIAL
INTENSITY WILL BE REDUCED TO 45 KT.

THE CENTER HAS MOVED SLOWLY WESTWARD SINCE SUNRISE...WITH THE
INITIAL MOTION ESTIMATED AT 270/2.  THE TRACK GUIDANCE MODELS
REMAIN IN EXCELLENT AGREEMENT THAT DANNY SHOULD TURN NORTHWARD OVER
THE NEXT 24-36 HR IN ADVANCE OF A COMPLEX DEEP-LAYER TROUGH MOVING
INTO THE EASTERN UNITED STATES.  AFTER THAT...THE STORM SHOULD
ACCELERATE NORTHEASTWARD INTO THE WESTERLIES...PASSING NEAR OR OVER
CAPE HATTERAS...SOUTHEASTERN NEW ENGLAND...AND THE CANADIAN
MARITIMES ON ITS WAY INTO THE NORTH ATLANTIC.  WITH THE MORE
WESTERLY INITIAL POSITION...THE TRACK GUIDANCE ENVELOPE HAS SHIFTED
SOMEWHAT WESTWARD DURING THE FIRST 48 HR...AND THE NEW FORECAST
TRACK IS ADJUSTED WESTWARD AS WELL.  WHILE THE TRACK IS STILL DOWN
THE MIDDLE OF THE GUIDANCE ENVELOPE...THE GFS...UKMET...NOGAPS...
AND CANADIAN MODELS ARE ALL TO THE LEFT OF THE NEW TRACK.  SOME
ADDITIONAL ADJUSTMENT TOWARD THE LEFT...TOWARD THE EAST COAST OF
THE U. S....MAY BE REQUIRED IF THIS TREND CONTINUES.
 
DANNY REMAINS IN AN AREA OF UPPER-LEVEL CONFLUENT FLOW ASSOCIATED
WITH THE PERSISTENT CYCLONIC SHEAR AXIS SEEN IN WATER VAPOR
IMAGERY.  IN ADDITION...BOTH WATER VAPOR IMAGERY AND SSM/IS TOTAL
PRECIPITABLE WATER IMAGERY SUGGEST THAT THE ENVIRONMENT NEAR DANNY
IS DRY.  THESE FACTORS...COMBINED WITH THE CURRENT LACK OF
ORGANIZATION...SUGGESTS THAT STRENGTHENING WILL BE SLOW AT BEST
DURING THE NEXT 24 HR.  THERE IS A WINDOW OF OPPORTUNITY FOR DANNY
TO STRENGTHEN FROM 24-36 HR AS IT IS FORECAST TO MOVE UNDER AN
UPPER-LEVEL ANTICYCLONE.  AFTER THAT...IT WILL ENCOUNTER STRONG
SOUTHWESTERLY FLOW ASSOCIATED WITH THE DEEP-LAYER TROUGH...WHICH
SHOULD CAUSE WEAKENING AND EXTRATROPICAL TRANSITION.  THE NEW
INTENSITY FORECAST CALLS FOR DANNY TO NOT REACH HURRICANE
STRENGTH...WITH A PEAK INTENSITY OF 60 KT IN 48 HR.  IT SHOULD BE
NOTED THAT THE GFDL AND HWRF STILL FORECAST DANNY TO BECOME A
HURRICANE BY 36 HR.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      27/2100Z 27.5N  73.5W    45 KT
 12HR VT     28/0600Z 28.5N  74.7W    45 KT
 24HR VT     28/1800Z 30.7N  75.0W    50 KT
 36HR VT     29/0600Z 34.4N  74.1W    55 KT
 48HR VT     29/1800Z 38.8N  71.6W    60 KT
 72HR VT     30/1800Z 46.5N  61.5W    50 KT...EXTRATROPICAL
 96HR VT     31/1800Z 50.0N  49.0W    40 KT...EXTRATROPICAL
120HR VT     01/1800Z 51.0N  32.0W    35 KT...EXTRATROPICAL
 
$$
FORECASTER BEVEN
 

WTNT45 KNHC 280232
TCDAT5
TROPICAL STORM DANNY DISCUSSION NUMBER   7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
1100 PM EDT THU AUG 27 2009
 
DANNY REMAINS VERY DISORGANIZED IN ITS SATELLITE PRESENTATION.
LITTLE DEEP CONVECTION HAS BEEN NOTED NEAR THE ESTIMATED CENTER.
THERE ARE A FEW CLUSTERS OF DEEP CONVECTION OVER THE EASTERN AND
NORTHERN PORTIONS OF THE CIRCULATION...BUT THIS CONVECTION SHOWS
LITTLE OR NO EVIDENCE OF BANDING FEATURES.  DROPSONDE DATA FROM THE
NOAA G-IV JET AIRCRAFT SUGGEST THAT THE CYCLONIC CIRCULATION OF
DANNY HAS LITTLE VERTICAL DEPTH.  A NOAA P-3 HURRICANE HUNTER
AIRCRAFT...CONDUCTING A RESEARCH MISSION IN DANNY THIS EVENING...
INDICATES THAT THE STRONGEST WINDS CONTINUE TO BE DISPLACED WELL TO
THE NORTHEAST OF THE CENTER.  PEAK WINDS REPORTED BY THE PLANE WERE
42 KT...SO THE INITIAL INTENSITY IS REDUCED TO 40 KT FOR THIS
ADVISORY.  DANNY HAS BEEN EXPERIENCING STRONG WEST-SOUTHWESTERLY
SHEAR DUE TO AN UPPER-LEVEL TROUGH AND CYCLONIC SHEAR AXIS TO ITS
WEST.  THERE IS STILL A WINDOW OF OPPORTUNITY FOR THE STORM TO
STRENGTHEN AS GLOBAL MODELS SHOW THE UPPER-LEVEL FLOW BECOMING MORE
ANTICYCLONIC...WITH SOME LESSENING OF THE SHEAR DURING THE NEXT 24
HOURS.  THEREFORE THE OFFICIAL FORECAST SHOWS SOME STRENGTHENING
OVER THE NEXT DAY OR SO.  HOWEVER BY 48 HOURS THE SHEAR OVER DANNY
IS EXPECTED TO BE 40 KT OR MORE SO ANY INTENSIFICATION OF THE
SYSTEM AS A TROPICAL CYCLONE SHOULD CEASE BY THAT TIME.  IN
FACT...BY 48 HOURS...THE GLOBAL MODELS AND THE FSU CYCLONE PHASE
SPACE ANALYSES IMPLY THAT DANNY MAY HAVE ALREADY BECOME AN
EXTRATROPICAL CYCLONE.
 
THE CENTER MEANDERED ABOUT DURING THE DAY...BUT LAST-LIGHT VISIBLE
IMAGERY AND DATA FROM THE AIRCRAFT INDICATED THAT A NORTH TO
NORTH-NORTHWESTWARD MOTION BEGAN SEVERAL HOURS AGO.  HOWEVER...THE
CENTER IS NEARLY IMPOSSIBLE TO DISCERN ON RECENT INFRARED IMAGES.
THE INITIAL MOTION IS AN UNCERTAIN 330/7.  THE TRACK FORECAST
REASONING IS BASICALLY UNCHANGED.  DANNY SHOULD MOVE ON A GENERALLY
NORTHWARD COURSE DURING THE NEXT DAY OR SO ON THE EAST SIDE OF A
SHORT WAVE TROUGH OVER THE SOUTHEASTERN UNITED STATES.  THEREAFTER
A DEEPENING LONG WAVE TROUGH OVER THE EASTERN U.S. SHOULD CARRY
DANNY OR ITS POST-TROPICAL COUNTERPART NORTH-NORTHEASTWARD TO
NORTHEASTWARD AT AN INCREASED FORWARD SPEED.  LATE IN THE FORECAST
PERIOD...THE CYCLONE SHOULD TURN EASTWARD AS IT BECOMES WELL
EMBEDDED IN THE MID-LATITUDE WESTERLIES.  THE OFFICIAL FORECAST IS
VERY SIMILAR TO THE PREVIOUS ONE AND IS CLOSE TO THE MODEL
CONSENSUS.
 
SINCE THE FORECAST TRACK CONTINUES TO KEEP THE AREA OF TROPICAL
STORM FORCE WINDS OFFSHORE...NO ADDITIONAL WATCHES OR WARNINGS ARE
BEING ISSUED FOR THE U.S. EAST COAST AT THIS TIME.  HOWEVER NEW
WATCHES AND/OR WARNINGS COULD BE REQUIRED ON FRIDAY...PARTICULARLY
IF THE FORECAST TRACK SHIFTS TO THE WEST.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/0300Z 28.4N  73.5W    40 KT
 12HR VT     28/1200Z 29.7N  74.5W    45 KT
 24HR VT     29/0000Z 32.5N  74.5W    50 KT
 36HR VT     29/1200Z 36.5N  73.0W    55 KT
 48HR VT     30/0000Z 40.5N  69.5W    55 KT
 72HR VT     31/0000Z 47.5N  59.0W    50 KT...EXTRATROPICAL
 96HR VT     01/0000Z 50.5N  46.0W    40 KT...EXTRATROPICAL
120HR VT     02/0000Z 51.0N  31.5W    35 KT...EXTRATROPICAL
 
$$
FORECASTER PASCH/BERG
 

WTNT45 KNHC 280840
TCDAT5
TROPICAL STORM DANNY DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
500 AM EDT FRI AUG 28 2009
 
AN AIR FORCE RECONNAISSANCE PLANE HAS BEEN IN THE AREA OF DANNY
SINCE AROUND 05 UTC AND FOUND THAT DANNY IS BARELY A TROPICAL
STORM...WITH THE STRONGEST WINDS CONFINED ONLY TO THE NORTHEAST OF
THE CENTER. THE INITIAL INTENSITY HAS BEEN LOWERED TO 35 KNOTS.
AFTER SEVERAL HOURS OF THE CENTER BEING COMPLETELY EXPOSED DUE TO
STRONG WESTERLY SHEAR...A NEW ROUND OF CONVECTION HAS RECENTLY
DEVELOPED NEAR THE CENTER. THE STRONG SHEAR NEARBY MOST LIKELY WILL
REMOVE THE CONVECTION ONCE AGAIN AT ANY TIME. SINCE GLOBAL MODELS
ARE BUILDING A WEAK UPPER-LEVEL RIDGE OVER THE CYCLONE WITHIN THE
NEXT 12 TO 24 HOURS...THERE IS A SMALL OPPORTUNITY FOR SLIGHT
STRENGTHENING DURING THIS PERIOD. THEREAFTER...WITH A LARGE TROUGH
APPROACHING DANNY...THE MOST LIKELY SCENARIO IS THAT THE CYCLONE
WILL INTERACT WITH THE MID-LATITUDE TROUGH AND BEGIN THE TRANSITION
TO AN EXTRATROPICAL CYCLONE BY 48 HOURS.

THE CENTER HAS BEEN MOVING BETWEEN THE NORTHWEST AND NORTH-NORTHWEST
DURING THE PAST FEW HOURS...BUT THE BEST LONG-TERM ESTIMATE OF THE
INITIAL MOTION IS 330 DEGREES AT 8 KT. THE LARGE TROUGH ALONG THE
EASTERN UNITED STATES WILL FORCE DANNY TO MOVE TOWARD THE NORTH AND
THEN NORTHEAST WITH INCREASING FORWARD SPEED AFTER 24 HOURS. 

MOST OF THE TRACK MODELS KEEP THE CENTER OF DANNY AWAY FROM THE
UNITED STATES EAST COAST...AND SINCE THE TROPICAL STORM FORCE WINDS 
ARE CONFINED TO THE EASTERN PORTION OF THE CYCLONE...IT IS NOT
NECESSARY TO ISSUE A TROPICAL STORM WARNING FOR THE REGION
CURRENTLY UNDER A TROPICAL STORM WATCH. THE TROPICAL STORM WATCH
REMAINS IN EFFECT IN CASE THE WIND FIELD BECOMES BETTER DEFINED ON
THE WESTERN SIDE OF DANNY DURING THE NEXT SEVERAL HOURS OR THE
FORECAST UNEXPECTEDLY SHIFTS TO THE WEST.
 
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/0900Z 29.5N  74.4W    35 KT
 12HR VT     28/1800Z 31.3N  74.7W    40 KT
 24HR VT     29/0600Z 34.2N  74.0W    45 KT
 36HR VT     29/1800Z 38.5N  71.5W    40 KT
 48HR VT     30/0600Z 42.5N  67.0W    40 KT
 72HR VT     31/0600Z 47.5N  59.0W    40 KT...EXTRATROPICAL
 96HR VT     01/0600Z 52.0N  47.0W    40 KT...EXTRATROPICAL
120HR VT     02/0600Z 54.0N  26.0W    45 KT...EXTRATROPICAL
 
$$
FORECASTER AVILA
 

WTNT45 KNHC 281441
TCDAT5
TROPICAL STORM DANNY DISCUSSION NUMBER   9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
1100 AM EDT FRI AUG 28 2009
 
THE CENTER OF DANNY REMAINS EXPOSED THIS MORNING...AND OVER THE PAST
COUPLE OF HOURS HAS BEEN MOVING ALMOST DUE WESTWARD AWAY FROM THE
DEEP CONVECTION. NOAA BUOY 41047 WELL SOUTHEAST OF THE CENTER
REPORTED A 1-MINUTE PEAK SUSTAINED WIND OF 31 KT AT 1100 UTC. THE
INITIAL INTENSITY IS HELD AT 35 KT...ASSUMING THAT HIGHER WINDS
STILL EXIST WELL EAST OF THE CENTER. AN AIR FORCE RESERVE HURRICANE
HUNTER AIRCRAFT WILL BE INVESTIGATING DANNY LATER THIS AFTERNOON TO
PROVIDE MORE INFORMATION ON ITS INTENSITY AND STRUCTURE.
 
THE INITIAL MOTION ESTIMATE IS 325/9...A COMPROMISE BETWEEN THE
SHORT TERM WESTWARD MOTION AND THE LONGER TERM NORTH-NORTHWESTWARD
MOTION OBSERVED OVERNIGHT. THE FORECAST IS ADJUSTED TOWARD THE WEST
DUE TO THE INITIAL MOTION AND ACTUALLY LIES WEST OF ALL THE
DYNAMICAL MODELS AT 12 HOURS...AS THESE MODELS IMMEDIATELY TURN
DANNY NORTHWARD. LATER IN THE FORECAST PERIOD...THE TRACK IS
VERY CLOSE TO THE TVCN MULTI-MODEL CONSENSUS. BY 36 HOURS...THIS
POSITION IS JUST SOUTH OF THE COAST OF MASSACHUSETTS...WITH THE
GFS...ECMWF...AND GFS ENSEMBLE MEAN SIGNIFICANTLY LEFT OF THE
CONSENSUS...AND MOST OF THE OTHER GUIDANCE CLUSTERED TO THE RIGHT.
BEYOND THAT TIME...DANNY SHOULD BE ACCELERATING TOWARD THE
NORTHEAST THROUGH THE CANADIAN MARITIMES AND EAST-NORTHEASTWARD
INTO THE NORTH ATLANTIC.
 
IT SHOULD BE NOTED THAT THERE ARE A COUPLE OF ALTERNATIVE SCENARIOS
THAT COULD OCCUR. THE SHALLOW BAM MODEL REPRESENTS AN EVEN MORE
WESTWARD TRACK THAT COULD OCCUR IF DANNY LOSES ALL OF ITS DEEP
CONVECTION. IT IS ALSO POSSIBLE THAT A NEW CENTER COULD RE-FORM
UNDER THE DEEP CONVECTION FARTHER EAST. EITHER OF THESE SCENARIOS
WOULD LIKELY REDUCE THE THREAT TO THE U.S. EAST COAST. 
 
THE INTENSITY FORECAST SHOWS THE POSSIBILITY FOR A LITTLE
STRENGTHENING IN THE NEXT 12 HOURS...BUT AFTER THAT TIME THE
CYCLONE WILL BE MOVING INTO A VERY UNFAVORABLE ENVIRONMENT...WITH
THE SHIPS MODEL SHOWING WIND SHEAR INCREASING TO OVER 30 KT BY 24
HOURS AS DANNY INTERACTS WITH A DEEP-LAYER TROUGH OVER THE EASTERN
UNITED STATES. THE GLOBAL MODELS AND PHASE SPACE DIAGRAMS SHOW THAT
DANNY WILL BEGIN EXTRATROPICAL TRANSITION BEGINNING BY 48
HOURS...AND THAT THE CYCLONE WILL BE FULLY EXTRATROPICAL BY 72
HOURS. THIS EVOLUTION IS REFLECTED IN THE OFFICIAL FORECAST...WHICH
SHOWS AN EXPANDING WIND FIELD AS DANNY MOVES FROM THE CANADIAN
MARITIMES INTO THE NORTH ATLANTIC.
 
DESPITE THE WESTWARD SHIFT IN THE TRACK...A TROPICAL STORM WARNING
WILL NOT BE ISSUED FOR THE COAST OF NORTH CAROLINA AT THIS
TIME...DUE TO THE CURRENT AND EXPECTED LIMITED EXTENT OF TROPICAL
STORM FORCE WINDS ON THE WEST SIDE OF THE CIRCULATION. THE TROPICAL
STORM WATCH REMAINS IN EFFECT IN CASE THE WIND FIELD BECOMES BETTER
DEFINED ON THE WESTERN SIDE OF DANNY OR IF THE FORECAST CONTINUES
TO SHIFT WESTWARD. A TROPICAL STORM WATCH MAY ALSO BE NEEDED FOR
PORTIONS OF THE COAST OF NEW ENGLAND LATER TODAY.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/1500Z 30.1N  75.5W    35 KT
 12HR VT     29/0000Z 32.5N  75.7W    40 KT
 24HR VT     29/1200Z 36.2N  74.1W    40 KT
 36HR VT     30/0000Z 40.7N  70.7W    40 KT
 48HR VT     30/1200Z 44.6N  65.1W    40 KT...INLAND
 72HR VT     31/1200Z 49.6N  52.5W    40 KT...EXTRATROPICAL
 96HR VT     01/1200Z 52.5N  38.0W    40 KT...EXTRATROPICAL
120HR VT     02/1200Z 54.5N  21.5W    45 KT...EXTRATROPICAL
 
$$
FORECASTER BRENNAN
 

WTNT45 KNHC 282035
TCDAT5
TROPICAL STORM DANNY DISCUSSION NUMBER  10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
500 PM EDT FRI AUG 28 2009
 
AFTER STALLING EARLIER THIS AFTERNOON...THE CENTER OF DANNY IS
FINALLY MOVING SLOWLY NORTHWARD OR NORTH-NORTHEASTWARD. DATA FROM AN
AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT SUGGEST THAT DANNY IS
STILL A MINIMAL TROPICAL STORM...BASED ON A 33-KT OBSERVATION FROM
THE SFMR IN THE SOUTHEASTERN QUADRANT.
 
THE INTENSITY FORECAST SHOWS THE POSSIBILITY FOR A LITTLE
STRENGTHENING IN THE SHORT TERM...AS THE INCREASING UPPER-LEVEL
DIVERGENCE COULD SUPPORT THE REDEVELOPMENT OF CONVECTION NEAR THE
CENTER. HOWEVER...BY 24 HOURS...DANNY WILL BE MOVING INTO A VERY
UNFAVORABLE ENVIRONMENT FOR A TROPICAL CYCLONE...WITH THE SHIPS
MODEL SHOWING WIND SHEAR INCREASING TO 35 KT BY THAT TIME. BY 36
HOURS...DANNY WILL BE OVER SSTS OF NEAR 20C...AND INTERACTING WITH
THE DEEP-LAYER BAROCLINIC TROUGH OVER THE EASTERN U.S.  MOST OF
THE LATEST GLOBAL MODELS AND PHASE SPACE DIAGRAMS SHOW THAT DANNY
WILL BE EXTRATROPICAL BY THAT TIME. THERE IS THE POTENTIAL FOR SOME
INTENSIFICATION OF DANNY LATE IN THE FORECAST PERIOD AS AN
EXTRATROPICAL CYCLONE OVER THE NORTH ATLANTIC.
 
THE GUIDANCE WAS INITIALIZED WITH A LONG TERM MOTION OF 315/08...
AND REMAINS IS GOOD AGREEMENT ON THE RAPID ACCELERATION OF DANNY
NORTHWARD AND NORTH-NORTHEASTWARD. IN FACT...THE MODEL SPREAD IS
SMALLER NOW THAN IT WAS EARLIER TODAY. THE OFFICIAL TRACK IS SLOWER
THAN THE MODEL CONSENSUS THROUGH MOST OF THE PERIOD DUE TO THE SLOW
INITIAL MOTION. FROM 24 TO 36 HOURS...THE NEW FORECAST IS SHIFTED
TO THE RIGHT OF THE PREVIOUS FORECAST TRACK...BUT DANNY IS STILL
EXPECTED TO MOVE CLOSE TO THE SOUTHEASTERN COAST OF NEW ENGLAND AND
APPROACH NOVA SCOTIA IN 36-48 HOURS.
 
DATA FROM THE AIRCRAFT SUGGEST THAT THE ONLY 34-KT WINDS ARE LOCATED
IN THE SOUTHEASTERN QUADRANT. THE LACK OF WINDS ON THE WEST SIDE OF
DANNY LESSEN THE THREAT FOR TROPICAL STORM WIND REACHING THE NORTH
CAROLINA OUTER BANKS. HOWEVER...THE WATCH IS LEFT IN PLACE IN CASE
THE WIND FIELD BECOMES BETTER DEFINED ON THE WESTERN SIDE OF DANNY.
AS DANNY BECOMES EXTRATROPICAL...ITS EXPANDING WIND FIELD MAY
IMPACT THE COAST OF NEW ENGLAND. THESE POTENTIAL IMPACTS WILL BE
HANDLED WITH GALE WARNINGS AND OTHER PRODUCTS ISSUED BY LOCAL NWS
OFFICES IN THAT REGION.
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/2100Z 30.4N  75.4W    35 KT
 12HR VT     29/0600Z 32.7N  75.8W    40 KT
 24HR VT     29/1800Z 37.3N  73.2W    40 KT
 36HR VT     30/0600Z 41.9N  68.2W    40 KT...EXTRATROPICAL
 48HR VT     30/1800Z 46.5N  61.4W    40 KT...EXTRATROPICAL
 72HR VT     31/1800Z 50.5N  49.5W    40 KT...EXTRATROPICAL
 96HR VT     01/1800Z 53.0N  35.0W    45 KT...EXTRATROPICAL
120HR VT     02/1800Z 55.0N  22.0W    50 KT...EXTRATROPICAL
 
$$
FORECASTER BRENNAN
 

WTNT45 KNHC 290240
TCDAT5
TROPICAL STORM DANNY DISCUSSION NUMBER  11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
1100 PM EDT FRI AUG 28 2009

DANNY REMAINS A POORLY ORGANIZED TROPICAL STORM.  THE STRONGEST
WINDS AND LARGEST AREAS OF CONVECTION ARE STILL WELL SOUTHEAST OF
THE CENTER...ALTHOUGH SOME DISORGANIZED CONVECTION HAS RECENTLY
FORMED NEAR THE CENTER.  JUST-RECEIVED QUIKSCAT DATA SHOWS ONE
RELIABLE-LOOKING 35 KT VECTOR SOUTHEAST OF THE CENTER...SO THE
INITIAL INTENSITY REMAINS 35 KT.  ANALYSES FROM CIMSS AT THE
UNIVERSITY OF WISCONSIN INDICATE ABOUT 15 KT OF SOUTHWESTERLY
VERTICAL WIND SHEAR AS DANNY IS BECOMING EMBEDDED IN FLOW BETWEEN
AN UPPER-LEVEL ANTICYCLONE NEAR 26N71W AND THE POWERFUL UPPER-LEVEL
TROUGH MOVING NORTHEASTWARD THROUGH THE SOUTHEASTERN UNITED STATES.

DANNY HAS CONTINUED ITS ERRATIC MOTION THIS EVENING.  JUST
BEFORE SUNSET...THE EXPOSED CENTER APPEARED TO BE MOVING NORTH-
NORTHEASTWARD OR NORTHEASTWARD.  SINCE THEN...THE CENTER HAS
DISAPPEARED UNDER CIRRUS CLOUDS...BUT IT SEEMS TO BE MOVING MORE
NORTHWARD AT A FASTER PACE.  THE INITIAL MOTION IS AN UNCERTAIN
020/10.  OTHER THAN THAT...THE TRACK FORECAST SCENARIO IS
UNCHANGED.  DANNY SHOULD ACCELERATE INTO THE WESTERLIES...MOVING
GENERALLY NORTH-NORTHEASTWARD FOR THE FIRST 24 HR OR SO...FOLLOWED
BY A TURN TO THE NORTHEAST AND EVENTUALLY EAST-NORTHEASTWARD.  THE
NEW FORECAST TRACK IS NUDGED TO THE EAST OF THE PREVIOUS TRACK
BASED ON THE INITIAL POSITION AND MOTION...AND LIES ALONG THE LEFT
EDGE OF THE TIGHTLY CLUSTERED TRACK GUIDANCE MODELS THROUGH 48 HR. 
THE TRACK CALLS FOR THE CENTER TO PASS EAST OF CAPE HATTERAS IN
ABOUT 12 HR...SOUTHEAST OF CAPE COD IN 24-30 HR...AND NEAR OR OVER
NOVA SCOTIA AND NEWFOUNDLAND IN 36-48 HR.

DANNY IS ABOUT OUT OF TIME TO STRENGTHEN AS A TROPICAL CYCLONE...AS
VERTICAL SHEAR OVER THE SYSTEM IS FORECAST TO INCREASE
SIGNIFICANTLY OVER THE NEXT 12-24 HR.  AFTER THAT...THE SYSTEM
SHOULD UNDERGO EXTRATROPICAL TRANSITION.  THE INTENSITY FORECAST IS
THE SAME AS THE PREVIOUS ADVISORY...CALLING FOR A LITTLE
INTENSIFICATION WHILE DANNY IS STILL TROPICAL...LITTLE CHANGE IN
STRENGTH THROUGH EXTRATROPICAL TRANSITION...THEN SOME
INTENSIFICATION AS AN EXTRATROPICAL LOW OVER THE NORTH ATLANTIC.
 
AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT SHOULD ARRIVE IN
DANNY AROUND 06Z TO BETTER DETERMINE THE POSITION AND INTENSITY.
AS DANNY BECOMES EXTRATROPICAL...ITS EXPANDING WIND FIELD MAY
IMPACT THE COAST OF NEW ENGLAND.  THESE POTENTIAL IMPACTS WILL BE
HANDLED WITH GALE WARNINGS AND OTHER PRODUCTS ISSUED BY LOCAL NWS
OFFICES IN THAT REGION.
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      29/0300Z 31.4N  74.9W    35 KT
 12HR VT     29/1200Z 34.7N  73.8W    40 KT
 24HR VT     30/0000Z 39.5N  70.1W    40 KT
 36HR VT     30/1200Z 44.0N  64.5W    40 KT...EXTRATROPICAL
 48HR VT     31/0000Z 47.3N  58.1W    40 KT...EXTRATROPICAL
 72HR VT     01/0000Z 51.5N  45.0W    40 KT...EXTRATROPICAL
 96HR VT     02/0000Z 53.5N  30.0W    45 KT...EXTRATROPICAL
120HR VT     03/0000Z 56.0N  14.0W    50 KT...EXTRATROPICAL
 
$$
FORECASTER BEVEN
 

WTNT45 KNHC 290843
TCDAT5
TROPICAL DEPRESSION DANNY DISCUSSION NUMBER  12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052009
500 AM EDT SAT AUG 29 2009
 
SATELLITE IMAGES...SURFACE OBSERVATIONS AND DATA FROM AN AIR FORCE
RECONNAISSANCE PLANE INDICATE THAT DANNY IS RAPIDLY BECOMING
ABSORBED BY A FRONTAL LOW WHICH IS DEVELOPING OVER NORTH CAROLINA.
IN FACT...THE PLANE TRAVERSED THE POSSIBLE LOCATION OF DANNY A
COUPLE TIMES AND DID NOT FIND ANY SIGNIFICANT CYCLONIC WIND
SHIFT NOR DID IT MEASURE TROPICAL STORM FORCE WINDS AT THE SURFACE.
THEREFORE...ADVISORIES ON DANNY HAVE BEEN TERMINATED AND THE
TROPICAL STORM WATCH HAS BEEN DISCONTINUED. THE EXTRATROPICAL LOW
WILL MOVE TOWARD THE NORTH-NORTHEAST AND THEN NORTHEAST AND ITS
POTENTIAL IMPACTS WILL BE HANDLED WITH GALE WARNINGS AND OTHER
PRODUCTS ISSUED BY LOCAL NWS OFFICES IN THAT REGION. ADDITIONAL
INFORMATION ON THIS SYSTEM CAN BE FOUND IN HIGH SEAS FORECASTS
ISSUED BY THE NATIONAL WEATHER SERVICE...UNDER AWIPS HEADER
NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      29/0900Z 34.3N  74.6W    30 KT...BECOMING ABSORBED
 12HR VT     29/1800Z 38.0N  73.0W    35 KT...EXTRATROPICAL
 24HR VT     30/0600Z 41.2N  69.2W    40 KT...EXTRATROPICAL
 36HR VT     30/1800Z 46.2N  62.8W    40 KT...EXTRATROPICAL
 48HR VT     31/0600Z 49.5N  56.0W    40 KT...EXTRATROPICAL
 72HR VT     01/0600Z 54.5N  43.5W    40 KT...EXTRATROPICAL
 96HR VT     02/0600Z 56.5N  27.0W    45 KT...EXTRATROPICAL
120HR VT     03/0600Z 57.0N  10.1W    50 KT...EXTRATROPICAL
 
$$
FORECASTER AVILA
 

