WTNT45 KNHC 102336
TCDAT5
TROPICAL DEPRESSION FIVE SPECIAL DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052010
730 PM EDT TUE AUG 10 2010
 
AN AIR FORCE HURRICANE HUNTER PLANE HAS JUST COMPLETED ITS
RECONNAISSANCE MISSION OF THE LOW PRESSURE SYSTEM OVER THE
SOUTHEASTERN GULF OF MEXICO.  THEY CONFIRMED THAT A SURFACE
CIRCULATION WAS PRESENT...AND THERE IS SUFFICIENT ORGANIZED DEEP
CONVECTION TO CLASSIFY THE SYSTEM AS A TROPICAL DEPRESSION AT THIS
TIME.  SEA SURFACE TEMPERATURES ARE VERY WARM ALONG THE PROJECTED
PATH OF THE CYCLONE...BUT THE UPPER-LEVEL WIND ENVIRONMENT IS NOT
IDEAL FOR STRENGTHENING WITH INCREASING EASTERLY SHEAR OVER THE
SYSTEM AS DEPICTED BY THE GLOBAL MODELS.  ONLY THE GFDL SOLUTION
SHOWS MORE THAN MODEST STRENGTHENING...BUT THAT MODEL HAS BEEN
KNOWN TO HAVE A HIGH BIAS AT TIMES.  THE OFFICIAL WIND SPEED
FORECAST IS VERY CLOSE TO THE RELIABLE STATISTICAL/DYNAMICAL LGEM
INTENSITY GUIDANCE AND TO THE NUMERICAL INTENSITY CONSENSUS.

SINCE THE CENTER IS STILL A BIT BROAD...THE INITIAL MOTION...
315/05...IS MORE UNCERTAIN THAN USUAL.  A MID-LEVEL RIDGE TO THE
NORTH SHOULD PRODUCE A TURN TOWARD THE WEST-NORTHWEST WITH SOME
ACCELERATION DURING THE NEXT 24 TO 36 HOURS.  THE OFFICIAL TRACK
FORECAST IS VERY SIMILAR TO THE DYNAMICAL CONSENSUS.

GIVEN THAT THIS SPECIAL ADVISORY IS BEING ISSUED SO CLOSE TO THE
TIME OF THE SCHEDULED INTERMEDIATE ADVISORY...THE NEXT ADVISORY ON
THIS SYSTEM WILL BE AT 0300 UTC.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/2330Z 26.0N  84.1W    30 KT
 12HR VT     11/0600Z 26.8N  85.1W    30 KT
 24HR VT     11/1800Z 28.1N  87.0W    35 KT
 36HR VT     12/0600Z 29.0N  89.0W    40 KT
 48HR VT     12/1800Z 29.7N  90.6W    30 KT...INLAND
 72HR VT     13/1800Z 31.0N  92.0W    25 KT...INLAND
 96HR VT     14/1800Z 33.0N  90.5W    20 KT...POST-TROP/REMNT LOW
 
$$
FORECASTER PASCH/KIMBERLAIN
 

WTNT45 KNHC 110234
TCDAT5
TROPICAL DEPRESSION FIVE DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052010
1100 PM EDT TUE AUG 10 2010
 
SATELLITE IMAGERY AND WSR-88D RADAR DATA SHOW THAT THE DEPRESSION
HAS CHANGED LITTLE IN ORGANIZATION OVER THE PAST FEW HOURS.  THE
INITIAL INTENSITY IS KEPT AT 30 KT IN ACCORD WITH A DVORAK ESTIMATE
FROM TAFB.  THE TROPICAL CYCLONE WILL BE TRAVERSING VERY WARM...
NEAR 30 DEG C...WATERS.  DYNAMICAL GUIDANCE...HOWEVER...INDICATES
THAT THE UPPER-LEVEL FLOW WILL BE ONLY MARGINALLY CONDUCIVE FOR
INTENSIFICATION WITH MODERATE EASTERLY SHEAR PREDICTED TO DEVELOP
OVER THE CYCLONE AS IT MOVES INTO THE NORTHERN GULF.  THE LATEST
GFDL MODEL RUN HAS BACKED OFF SOMEWHAT FROM ITS PREVIOUS INTENSITY
FORECAST AND IS NOW CLOSER TO THE STATISTICAL DYNAMICAL GUIDANCE. 
THE OFFICIAL WIND SPEED FORECAST IS VERY SIMILAR TO THE PREVIOUS
ONE AND IS CLOSE TO THE NUMERICAL INTENSITY CONSENSUS...ICON.

THE CENTER HAS BEEN DIFFICULT TO LOCATE BUT BASED ON THE LATEST
SATELLITE FIXES AND CONTINUITY...THE INITIAL MOTION IS ESTIMATED TO
BE 320/4.  NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE TRACK
FORECAST FROM THE PREVIOUS PACKAGE.  THE DEPRESSION IS EXPECTED TO
BE STEERED BY A DEEP LAYER EASTERLY FLOW SOUTH OF A MID- TO
UPPER-LEVEL RIDGE ANCHORED OVER THE SOUTHEASTERN UNITED STATES
DURING THE NEXT 24 TO 48 HOURS. THIS FLOW REGIME SHOULD CAUSE THE
CYCLONE TO TURN WEST-NORTHWESTWARD WITH AN INCREASE IN FORWARD
SPEED AS IT APPROACHES THE NORTHERN GULF COAST.  THEREAFTER...A
TURN TO THE NORTHEAST IS EXPECTED AS THE SYSTEM MOVES AROUND THE
NORTHWESTERN PERIPHERY OF THE RIDGE.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/0300Z 26.2N  84.2W    30 KT
 12HR VT     11/1200Z 27.3N  85.7W    30 KT
 24HR VT     12/0000Z 28.4N  87.5W    35 KT
 36HR VT     12/1200Z 29.2N  89.2W    40 KT
 48HR VT     13/0000Z 29.7N  90.3W    35 KT...INLAND
 72HR VT     14/0000Z 31.0N  91.0W    30 KT...INLAND
 96HR VT     15/0000Z 33.5N  89.0W    20 KT...POST-TROP/REMNT LOW
120HR VT     16/0000Z...DISSIPATED
 
$$
FORECASTER PASCH/KIMBERLAIN
 

WTNT45 KNHC 110903
TCDAT5
TROPICAL DEPRESSION FIVE DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052010
500 AM EDT WED AUG 11 2010
 
SATELLITE IMAGERY...RADAR DATA...AND REPORTS FROM AN AIR FORCE
RESERVE RECONNAISSANCE AIRCRAFT INDICATE THE DEPRESSION HAS NOT
CHANGED ITS ORGANIZATION SINCE THE LAST ADVISORY. CONVECTION HAS
ERODED CONSIDERABLY...AS HAS THE LOW-LEVEL CIRCULATION...WHICH IS
LIKELY DUE TO COOL DOWNDRAFTS CAUSED BY THE ENTRAINMENT OF DRY
MID-LEVEL AIR TO THE WEST OF THE CYCLONE. THE INITIAL INTENSITY IS
BEING HELD AT A GENEROUS 30 KT BASED ON SURFACE OBS OF 25-27 KT IN
SOME OF THE OUTER RAINBANDS AND A FEW UNCONTAMINATED SFMR WINDS OF
25 KT MEASURED BY THE RECON AIR AIRCRAFT. 

THE INITIAL MOTION ESTIMATE IS AN UNCERTAIN 310/09 DUE TO DIFFICULTY
IN LOCATING THE SURFACE CENTER. DESPITE THE DISRUPTION OF THE
LOW-LEVEL WIND FIELD...00Z UPPER-AIR DATA INDICATES THAT THE
DEPRESSION IS WELL DEFINED FROM 850 MB THROUGH AT LEAST 400 MB. ALL
OF THE MODELS ARE IN GOOD AGREEMENT ON TD-5 MOVING NORTHWEST TO
WEST-NORTHWESTWARD UNTIL LANDFALL AROUND 48 HOURS. HOWEVER...A
GRADUAL DECREASE IN FORWARD SPEED IS EXPECTED BY 36 HOURS AS A
MID-LEVEL SHORTWAVE TROUGH OVER THE CENTRAL DIGS SOUTHEASTWARD AND
CREATES A WEAKNESS IN THE SUBTROPICAL RIDGE ALONG THE CENTRAL GULF
COAST. THE EXACT TIMING OF THE WEAKNESS DEVELOPING WILL DETERMINE
HOW FAR WEST THE CYCLONE MOVES BEFORE TURNING NORTHWARD. THE
OFFICIAL FORECAST TRACK IS A LITTLE TO THE EAST OF THE PREVIOUS
ADVISORY...AND IS ALONG THE WESTERN EDGE OF THE GUIDANCE ENVELOPE.
 
ALTHOUGH THE DEPRESSION IS LACKING CONVECTIVE ORGANIZATION AT THIS
TIME...THE OVERALL STRUCTURE OF THE CYCLONE SUPPORTS THE
REDEVELOPMENT OF CONVECTION LATER TODAY AFTER THE DRY MID-LEVEL AIR
HAS MIXED AND THE LOW-LEVEL WIND FIELD HAS RECOVERED. NONE OF THE
GLOBAL MODELS ARE BULLISH ON THIS SYSTEM BECOMING MUCH STRONGER
THAN ITS CURRENT INTENSITY..DESPITE A VERY FAVORABLE UPPER-LEVEL
FLOW PATTERN THAT IS FORECAST TO DEVELOP ALONG THE GULF COAST BY
36-48 HOURS. THE GFDL AND HWRF MODELS DROP THE PRESSURE TO 986 AND
968 MB...RESPECTIVELY SHORTLY AFTER LANDFALL...AND THE HWRF MODEL
IS FORECASTING THE CYCLONE TO REACH HURRICANE STRENGTH RIGHT AT
LANDFALL. THE OFFICIAL INTENSITY FORECAST IS A BLEND OF THE VARIOUS
INTENSITY MODELS AND IS ONLY SLIGHTLY HIGHER THAN THE PREVIOUS
ADVISORY.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/0900Z 26.8N  85.1W    30 KT
 12HR VT     11/1800Z 27.7N  86.4W    30 KT
 24HR VT     12/0600Z 28.7N  88.0W    35 KT
 36HR VT     12/1800Z 29.5N  89.2W    40 KT
 48HR VT     13/0600Z 30.3N  89.4W    45 KT
 72HR VT     14/0600Z 31.0N  89.5W    35 KT...INLAND
 96HR VT     15/0600Z 33.5N  87.5W    20 KT...POST-TROP/REMNT LOW
120HR VT     16/0600Z...DISSIPATED INLAND
 
$$
FORECASTER STEWART
 

WTNT45 KNHC 111444
TCDAT5
TROPICAL DEPRESSION FIVE DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052010
1100 AM EDT WED AUG 11 2010
 
VISIBLE SATELLITE IMAGERY AND BUOY REPORTS INDICATE THAT THE
CIRCULATION OF THE DEPRESSION REMAINS VERY LARGE AND ELONGATED.
BANDS OF SHOWERS AND THUNDERSTORMS ARE LOCATED AROUND THE PERIPHERY
OF THE DEPRESSION BUT REMAIN LIMITED NEAR THE CENTER.  IT APPEARS
THAT THE CENTER...SUCH AS IT IS...REFORMED OVERNIGHT TO THE
NORTHWEST OF THE EARLIER ESTIMATES.  A MEAN CENTER OF THE OVERALL
SYSTEM RATHER THAN A WIND CENTER WAS USED FOR THE ADVISORY
POSITION.  THE INITIAL INTENSITY WAS LOWERED TO 25 KT THIS
MORNING...AND THESE WINDS ARE LIMITED TO A FEW RAIN BANDS IN THE
EASTERN SEMICIRCLE.
 
DUE TO THE POOR ORGANIZATION OF THE SYSTEM...THE INITIAL MOTION IS
HIGHLY UNCERTAIN. THE BEST ESTIMATE IS 305/10. THE TRACK GUIDANCE
HAS NOT CHANGED THIS MORNING AND CONTINUES TO INDICATE A NORTHWEST
MOTION AROUND THE SOUTHWEST SIDE OF A MID- TO UPPER-LEVEL RIDGE
LOCATED NEAR THE SOUTHEASTERN UNITED STATES COAST. THIS MOTION IS
EXPECTED TO CONTINUE UNTIL LANDFALL IN ABOUT 24 HOURS. THEREAFTER...
THE RIDGE IS FORECAST TO SHIFT SOUTH AND WEAKEN...WHICH IS EXPECTED
TO CAUSE THE DEPRESSION TO SLOW DOWN AND TURN TOWARD THE NORTH AND
THEN NORTHEAST. THE OFFICIAL FORECAST IS CLOSE TO THE PREVIOUS
ADVISORY...BUT IS A LITTLE FASTER DUE TO THE UPDATED INITIAL
POSITION.
 
ALTHOUGH THE UPPER-LEVEL PATTERN IS FORECAST TO GRADUALLY BECOME
MORE CONDUCIVE FOR STRENGTHENING...THE SPRAWLING STRUCTURE OF THE
DEPRESSION SUGGESTS THAT ANY INTENSIFICATION WOULD BE SLOW.  IN
ADDITION...THE SYSTEM SHOULD NOW HAVE LESS TIME OVER WATER THAN
PREVIOUSLY EXPECTED.  AS A RESULT...THE NEW INTENSITY FORECAST IS
LOWERED FROM THE PREVIOUS ADVISORY...BUT IS STILL A LITTLE ABOVE
THE SHIPS/LGEM GUIDANCE.  ALTHOUGH THE GFDL AND HWRF ARE MORE
AGGRESSIVE...THE INITIALIZATION OF THESE MODELS IS UNLIKELY TO
ACCURATELY REFLECT THE CURRENT CYCLONE STRUCTURE.
 
ONE SHOULD NOT FOCUS ON THE EXACT TRACK OF WEAK TROPICAL
CYCLONES SINCE MOST OF THE ASSOCIATED WEATHER IS TYPICALLY WELL
REMOVED FROM THE CENTER.  THIS IS CERTAINLY THE CASE WITH THIS
DEPRESSION.  IF THE DEPRESSION SLOWS DOWN AS FORECAST AFTER
LANDFALL...HEAVY RAINFALL WOULD BECOME THE PRIMARY THREAT.

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/1500Z 27.8N  86.8W    25 KT
 12HR VT     12/0000Z 28.6N  88.1W    30 KT
 24HR VT     12/1200Z 29.6N  89.4W    35 KT
 36HR VT     13/0000Z 30.4N  90.1W    30 KT...INLAND
 48HR VT     13/1200Z 31.2N  90.2W    25 KT...INLAND
 72HR VT     14/1200Z 32.6N  89.3W    20 KT...POST-TROP/REMNT LOW
 96HR VT     15/1200Z 34.0N  87.5W    20 KT...POST-TROP/REMNT LOW
120HR VT     16/1200Z...DISSIPATED
 
$$
FORECASTER BROWN/CANGIALOSI
 

WTNT45 KNHC 112035
TCDAT5
TROPICAL DEPRESSION FIVE DISCUSSION NUMBER   5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052010
400 PM CDT WED AUG 11 2010
 
SATELLITE...BUOY...AND AIR FORCE RECONNAISSANCE AIRCRAFT DATA
INDICATE THAT THE DEPRESSION LACKS A WELL-DEFINED SURFACE CENTER.
IN ADDITION...THE CONVECTIVE ORGANIZATION OF THE SYSTEM HAS
DECREASED OVER THE PAST 24 HOURS.  EVEN THOUGH A LARGE...BROAD...
AND ELONGATED CIRCULATION REMAINS...THIS SYSTEM NO LONGER MEETS THE
DEFINITION OF A TROPICAL CYCLONE AND THIS WILL BE THE LAST NHC
ADVISORY.
 
THE REMNANTS OF THE DEPRESSION ARE STILL FORECAST TO MOVE ONSHORE
ALONG THE NORTHERN GULF OF COAST WITHIN THE NEXT DAY OR SO.  THIS
SYSTEM STILL HAS THE POTENTIAL TO PRODUCE HEAVY RAINFALL OVER A
LARGE PORTION OF THE SOUTHEASTERN UNITED STATES DURING THE NEXT
FEW DAYS. ADDITIONAL INFORMATION ON THE RAINFALL THREAT CAN BE FOUND
IN FORECASTS ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER
AND LOCAL NATIONAL WEATHER SERVICE OFFICES.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/2100Z 28.3N  87.6W    25 KT
 12HR VT     12/0600Z...DISSIPATED
 
$$
FORECASTER BROWN
 

