WTNT42 KNHC 142041
TCDAT2
 
TROPICAL STORM GERT DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072011
500 PM AST SUN AUG 14 2011
 
DEEP CONVECTION HAS CONTINUED TO DEVELOP OVER THE CENTER OF TROPICAL
STORM GERT AND SMALL BANDING FEATURES HAVE BEEN TRYING TO DEVELOP
IN THE NORTH AND EAST QUADRANTS OF THE CIRCULATION. AN AIR FORCE
RESERVE UNIT RECONNAISSANCE AIRCRAFT INVESTIGATING THE CYCLONE THIS
AFTERNOON FOUND MAXIMUM 850 MB FLIGHT-LEVEL WINDS OF 43 KT IN THE
SOUTHEAST QUADRANT ALONG WITH UNCONTAMINATED SFMR WINDS OF 39 AND
41 KT. THE SFMR WINDS CORRELATE WELL WITH AN EARLIER 1324Z ASCAT
PASS THAT INDICATED SURFACE WINDS OF NEAR 40 KT IN THE SAME GENERAL
AREA OF THE CYCLONE CIRCULATION. BASED ON THE RECENT SFMR WINDS AND
EARLIER ASCAT WINDS...THE INITIAL INTENSITY IS INCREASED TO 40 KT.

NOW THAT GERT HAS REDEVELOPED DEEP CONVECTION NEAR THE CENTER AND
HAS BECOME A MORE VERTICALLY DEEP SYSTEM...THE TROPICAL STORM HAS
STARTED MOVING NORTH-NORTHWESTWARD...OR 335/07...TOWARD A WEAKNESS
IN THE SUBTROPICAL RIDGE. WATER VAPOR IMAGERY INDICATES A
FAST-MOVING SHORTWAVE TROUGH PASSING EASTWARD OVER AND NORTH OF
BERMUDA WITH A SHORTWAVE RIDGE IN ITS WAKE...WHICH MAY ALLOW FOR
THE SUBTROPICAL RIDGE TO BRIEFLY BUILD BACK WESTWARD AND CREATE
SOME STAIR-STEP MOTIONS TO THE NORTH-NORTHWEST AND NORTH.
HOWEVER...ALL OF THE GLOBAL MODELS ARE IN EXCELLENT AGREEMENT ON A
LARGE MID-LATITUDE TROUGH CURRENTLY OVER THE EASTERN U.S. MOVING
STEADILY EASTWARD AND GRADUALLY ERODING THE WESTERN PERIPHERY OF
THE MID-LEVEL RIDGE ALONG 32N LATITUDE FOR THE NEXT 24-36 HOURS. AS
A RESULT... THE STEERING FLOW SHOULD BECOME MORE SOUTHERLY AND
STEER GERT NORTHWARD FOR THE NEXT 24 HOURS OR SO...AND THEN
ACCELERATE THE CYCLONE NORTHEASTWARD THROUGH THE REMAINDER OF THE
FORECAST PERIOD. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE
PREVIOUS ADVISORY THROUGH 48 HOURS AND LIES CLOSE TO THE TIGHTLY
PACKED GLOBAL MODEL SUITE.

GERT HAS MOVED INTO A WEAK VERTICAL SHEAR REGION ON THE NORTH SIDE
OF A SMALL UPPER-LEVEL LOW...WHICH HAS ALLOWED DEEP CONVECTION TO
PERSIST AND PRODUCE A SMALL UPPER-LEVEL ANTICYCLONE OVER THE STORM.
THIS FAVORABLE UPPER-LEVEL FLOW REGIME...ALONG WITH WARM SSTS ABOVE
28C...IS EXPECTED TO PERSIST FOR THE NEXT 24 HOURS OT SO. THIS
SHOULD ALLOW FOR AT LEAST MODEST STRENGTHENING. AFTER
THAT...THERMODYNAMIC CONDITIONS ARE FORECAST BECOME LESS
CONDUCIVE...WHICH SHOULD ALLOW FOR ONLY SLIGHT STRENGTHENING EVEN
THOUGH THE VERTICAL SHEAR IS EXPECTED TO BE FAIRLY LOW. BY 48
HOURS...GERT WILL BE MOVING OVER MUCH COOLER WATER AND
SOUTHWESTERLY VERTICAL SHEAR IS EXPECTED TO INCREASE ABOVE 30 KT.
THIS COMBINATION OF UNFAVORABLE ENVIRONMENTAL CONDITIONS SHOULD
CAUSE GERT TO MAKE THE TRANSITION INTO A POST-TROPICAL CYCLONE. THE
INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND CLOSELY
FOLLOWS THE SHIPS AND LGEM INTENSITY MODELS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  14/2100Z 28.9N  63.2W   40 KT  45 MPH
 12H  15/0600Z 30.3N  63.8W   40 KT  45 MPH
 24H  15/1800Z 32.3N  63.6W   45 KT  50 MPH
 36H  16/0600Z 34.9N  61.8W   50 KT  60 MPH
 48H  16/1800Z 38.9N  58.2W   50 KT  60 MPH
 72H  17/1800Z 46.0N  45.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  18/1800Z...DISSIPATED
 
$$
FORECASTER STEWART
 

WTNT42 KNHC 150232
TCDAT2
 
TROPICAL STORM GERT DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072011
1100 PM AST SUN AUG 14 2011
 
ON SATELLITE IMAGERY...GERT IS CHARACTERIZED BY A FAIRLY CIRCULAR
AREA OF DEEP CONVECTION BUT IS LACKING IN BANDING FEATURES.  A
SMALL UPPER-LEVEL ANTICYCLONE THAT FORMED OVER THE STORM IS
PROVIDING SOME MODEST OUTFLOW...PARTICULARLY OVER THE SOUTHERN
SEMICIRCLE OF THE CIRCULATION.  BASED ON THE AIRCRAFT OBSERVATIONS
FROM A FEW HOURS AGO...THE MAXIMUM WINDS ARE ESTIMATED TO BE 40
KT...WHICH IS A LITTLE ABOVE THE LATEST DVORAK INTENSITY ESTIMATES. 
GERT IS LIKELY TO REMAIN OVER WARM WATERS AND IN A WEAK SHEAR
ENVIRONMENT FOR ANOTHER DAY OR SO...WHICH SHOULD ALLOW FOR SOME
INTENSIFICATION.  BY AROUND 48 HOURS...GLOBAL MODELS INDICATE AN
ABRUPT INCREASE IN VERTICAL SHEAR AS GERT APPROACHES A BELT OF
STRONG UPPER-LEVEL WESTERLIES.  THE OFFICIAL INTENSITY FORECAST IS
SLIGHTLY BELOW THE MODEL CONSENSUS.  IN 72 HOURS...PERHAPS
SOONER...GERT IS LIKELY TO BECOME EMBEDDED IN A FRONTAL ZONE AND
TRANSFORMED INTO AN EXTRATROPICAL CYCLONE.  BEYOND THAT TIME...THE
SYSTEM IS EXPECTED TO BECOME ABSORBED BY A LARGE HIGH-LATITUDE LOW
PRESSURE SYSTEM.

LATEST SATELLITE IMAGES INDICATE THAT THE FORWARD SPEED IS
INCREASING AND THE MOTION IS ESTIMATED TO BE AROUND 345/10.  GERT
IS MOVING BETWEEN A RATHER DEEP MID-LEVEL TROUGH THAT IS NEARING
THE U.S. EAST COAST AND A SUBTROPICAL HIGH OVER THE CENTRAL
ATLANTIC.  THE TRACK MODEL GUIDANCE IS IN GOOD AGREEMENT ON A
GRADUAL TURN TOWARD THE NORTH...THEN NORTH-NORTHEAST AND EVENTUALLY
NORTHEAST WITH INCREASING FORWARD SPEED OVER THE NEXT FEW DAYS. 
THE CURRENT OFFICIAL FORECAST IS A LITTLE SLOWER THAN THE LATEST
MULTI-MODEL CONSENSUS AND SLIGHTLY FASTER THAN THE PREVIOUS NHC
FORECAST.

INTERESTS IN BERMUDA ARE REMINDED NOT TO FOCUS ON THE EXACT FORECAST
TRACK OF GERT AS ONLY A SLIGHT DEVIATION TO THE LEFT DURING THE
NEXT 12 HOURS COULD BRING STRONG WINDS CLOSE TO...OR OVER...THE
ISLAND.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  15/0300Z 30.2N  63.3W   40 KT  45 MPH
 12H  15/1200Z 31.9N  63.4W   45 KT  50 MPH
 24H  16/0000Z 34.7N  62.2W   50 KT  60 MPH
 36H  16/1200Z 38.5N  59.5W   55 KT  65 MPH
 48H  17/0000Z 42.0N  55.0W   50 KT  60 MPH
 72H  18/0000Z 47.0N  40.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  19/0000Z...DISSIPATED
 
$$
FORECASTER PASCH
 

WTNT42 KNHC 150847
TCDAT2
 
TROPICAL STORM GERT DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072011
500 AM AST MON AUG 15 2011
 
GERT HAS STRENGTHENED OVERNIGHT.  AN 0543 UTC AMSR-E PASS AND
DOPPLER RADAR DATA FROM BERMUDA INDICATE THAT GERT HAS A FAIRLY
WELL-DEVELOPED INNER CORE AND A SPIRAL BAND THAT WRAPS ABOUT
THREE-QUARTERS OF THE WAY AROUND THE CENTER.  IN ADDITION...
SATELLITE IMAGES INDICATE THAT BANDING FEATURES HAVE BECOME MORE
ESTABLISHED DURING THE PAST SEVERAL HOURS.  THE INITIAL WIND SPEED
IS INCREASED TO 50 KT...WHICH IS SLIGHTLY HIGHER THAN THE DVORAK
CLASSIFICATIONS FROM TAFB AND SAB.  THERE IS STILL SOME NORTHERLY
SHEAR IMPACTING THE CYCLONE...AS SEEN IN THE UW-CIMSS SATELLITE
ANALYSIS AND THE SOUTHWARD TILT WITH HEIGHT OF THE CIRCULATION
CENTER IN THE AMSR-E IMAGERY.  AN AIR FORCE RESERVE RECONNAISSANCE
AIRCRAFT WILL BE INVESTIGATING GERT LATER THIS MORNING AND WILL
PROVIDE A BETTER ASSESSMENT OF ITS INTENSITY.
 
THE TROPICAL STORM APPEARS TO HAVE TURNED TO THE NORTH DURING THE
PAST 6 HOURS...AND THE LATEST INITIAL MOTION ESTIMATE IS 355/12.
GERT IS FORECAST TO TURN NORTH-NORTHEASTWARD AND THEN NORTHEASTWARD
AND GAIN FORWARD SPEED DURING THE NEXT FEW DAYS AS IT BECOMES
EMBEDDED IN THE STRONGER FLOW TO THE EAST OF A DEEP-LAYER TROUGH
MOVING OFFSHORE OF THE UNITED STATES EAST COAST.  THE OFFICIAL
FORECAST IS ESSENTIALLY AN UPDATE OF THE PREVIOUS ONE AND IS NEAR
THE MULTI-MODEL CONSENSUS.
 
SOME ADDITIONAL INTENSIFICATION OF GERT APPEARS LIKELY DURING THE
NEXT 24 HOURS AS IT REMAINS OVER RELATIVELY WARM WATER AND BENEATH
AN UPPER-LEVEL ANTICYCLONE.  AFTER 24 HOURS...GERT IS FORECAST TO
MOVE OVER WATERS COOLER THAN 26C...WHICH SHOULD INDUCE SOME
WEAKENING.  IN 2 TO 3 DAYS THE STORM IS FORECAST TO MOVE INTO AN
ENVIRONMENT OF STRONG SOUTHWESTERLY SHEAR AND WATERS COOLER THAN
20C...WHICH SHOULD RESULT IN EXTRATROPICAL TRANSITION DURING THAT
TIME PERIOD.  THE GLOBAL MODELS ARE IN AGREEMENT THAT A FRONT WILL
ABSORB GERT IN 3 TO 4 DAYS.
 
INTERESTS IN BERMUDA ARE REMINDED NOT TO FOCUS ON THE EXACT FORECAST
TRACK OF GERT...AS ONLY A SLIGHT DEVIATION TO THE LEFT DURING THE
NEXT 6 TO 12 HOURS COULD BRING STRONG WINDS CLOSE TO...OR OVER...THE
ISLAND.

FORECAST POSITIONS AND MAX WINDS
 
INIT  15/0900Z 31.3N  63.4W   50 KT  60 MPH
 12H  15/1800Z 33.5N  62.9W   55 KT  65 MPH
 24H  16/0600Z 36.8N  60.8W   60 KT  70 MPH
 36H  16/1800Z 40.3N  57.2W   55 KT  65 MPH
 48H  17/0600Z 43.0N  51.5W   50 KT  60 MPH
 72H  18/0600Z 48.0N  36.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  19/0600Z...DISSIPATED
 
$$
FORECASTER CANGIALOSI/BRENNAN
 

WTNT42 KNHC 151441
TCDAT2
 
TROPICAL STORM GERT DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072011
1100 AM AST MON AUG 15 2011
 
THE PRESENTATION OF GERT IN DOPPLER RADAR IMAGERY FROM BERMUDA 
HAS INDICATED BRIEF PERIODIC TIGHTENING OF THE INNER CORE
CIRCULATION...INCLUDING A SMALL 6-8 NMI DIAMETER EYE-LIKE
FEATURE...ONLY TO HAVE THE CONVECTION WEAKEN OR DISSIPATE 
DUE TO INTRUSIONS OF DRY AIR. AN AIR FORCE RESERVE RECON AIRCRAFT
INVESTIGATING THE CYCLONE HAS FOUND MAXIMUM 850 MB FLIGHT-LEVEL
WINDS OF 53 KT AND A FEW UNCONTAMINATED 49-51 KT SFMR WINDS IN 
THE EASTERN SEMICIRCLE...ACCOMPANIED BY A MINIMUM PRESSURE OF NEAR
1000 MB. BASED ON THIS INFORMATION...THE INTENSITY IS SET AT 50 KT
FOR THIS ADVISORY.

THE INITIAL MOTION ESTIMATE IS 010/10 KT. THERE IS NO CHANGE TO THE
PREVIOUS FORECAST REASONING. GERT HAS BEEN MOVING NORTHWARD THROUGH
A BREAK IN THE SUBTROPICAL RIDGE AND HAS NOW REACHED THE AXIS OF
THE EAST-WEST ORIENTED RIDGE THAT LIES ALONG 32N LATITUDE. AS THE
LARGE FULL LATITUDE TROUGH CURRENTLY MOVING OFF THE U.S. EAST COAST
CONTINUES ITS EASTWARD PROGRESS...GERT SHOULD GRADUALLY ACCELERATE
AND TURN TOWARD THE NORTH-NORTHEAST LATER TODAY AND TOWARD THE
NORTHEAST BY LATE TONIGHT OR TUESDAY. THE OFFICIAL TRACK FORECAST
IS A LITTLE TO THE RIGHT OF THE PREVIOUS TRACK AND IS A BLEND OF
THE ECMWF AND GFS MODEL SOLUTIONS.
 
SOME FURTHER INTENSIFICATION OF GERT IS POSSIBLE DURING THE NEXT 24
HOURS AS THE CYCLONE REMAINS OVER RELATIVELY WARM WATER AND BENEATH
AN UPPER-LEVEL ANTICYCLONE. HOWEVER...GERT IS A SMALLER THAN AVERAGE
SIZE TROPICAL CYCLONE...WHICH MEANS IT WILL BE SUSCEPTIBLE TO
INTRUSIONS OF DRY AIR AND SLIGHT INCREASES IN VERTICAL SHEAR. AS A
RESULT...THE INTENSITY FORECAST IS BEING HELD JUST BELOW HURRICANE
STRENGTH. BY 24 HOURS...GERT WILL BE MOVING OVER SEA-SURFACE
TEMPERATURES COOLER THAN 26C...AND OVER WATER COOLER THAN 20C BY 48
HOURS. AS A RESULT...GRADUAL WEAKENING IS EXPECTED AFTER 24 HOURS
AND EXTRATROPICAL TRANSITION IS EXPECTED TO OCCUR BY 48 HOURS WHEN
THE CYCLONE BEGINS TO MERGE WITH A FRONTAL SYSTEM AND ALSO BEGINS
TO FEEL THE EFFECTS OF STRONG SOUTHWESTERLY UPPER-LEVEL WIND SHEAR.
THE INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND
CLOSELY FOLLOWS THE SHIPS AND LGEM MODEL SOLUTIONS. EXTRATROPICAL
INTENSITY FORECASTS WERE PROVIDED BY THE NOAA OCEAN PREDICTION
CENTER.
 
THE BERMUDA WEATHER SERVICE HAS DISCONTINUED THE TROPICAL STORM
WARNING FOR BERMUDA.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  15/1500Z 32.0N  63.2W   50 KT  60 MPH
 12H  16/0000Z 34.3N  62.0W   55 KT  65 MPH
 24H  16/1200Z 37.8N  59.0W   60 KT  70 MPH
 36H  17/0000Z 40.8N  54.6W   55 KT  65 MPH
 48H  17/1200Z 43.4N  48.5W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  18/1200Z 48.5N  33.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  19/1200Z...DISSIPATED
 
$$
FORECASTER STEWART
 

WTNT42 KNHC 152033
TCDAT2
 
TROPICAL STORM GERT DISCUSSION NUMBER   8
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072011
500 PM AST MON AUG 15 2011
 
RADAR DATA FROM BERMUDA AND SATELLITE IMAGERY INDICATE GERT HAS
CHANGED LITTLE IN APPEARANCE SINCE THE PREVIOUS ADVISORY. THE LAST
RECON FLIGHT LEG THROUGH THE SOUTHEAST QUADRANT PRODUCED AN 850 MB
FLIGHT-LEVEL WIND OF 61 KT...WHICH EQUATES TO ROUGHLY 49 KT AT THE
SURFACE. GIVEN THE APPARENT STEADY NATURE OF THE CYCLONE...THE
INTENSITY IS BEING HELD AT 50 KT FOR THIS ADVISORY...WHICH IS CLOSE
TO A BLEND OF SATELLITE ESTIMATES OF 55 KT FROM TAFB AND 45 KT FROM
SAB...RESPECTIVELY . UPPER-LEVEL OUTFLOW IS FAIR IN ALL
QUADRANTS...EXCEPT RESTRICTED TO THE NORTHEAST.

THERE IS NO CHANGE TO THE PREVIOUS FORECAST RATIONALE. GERT HAS
MOVED NORTH OF THE SUBTROPICAL RIDGE AXIS AND IS NOW MOVING TO THE
NORTH-NORTHEAST OR 020/12. A GRADUAL TURN TOWARD THE NORTHEAST
ACCOMPANIED BY A STEADY INCREASE IN FORWARD SPEED IS EXPECTED
THROUGH THE REMAINDER OF THE FORECAST PERIOD AS GERT COMES UNDER
THE INFLUENCE OF INCREASING SOUTHWESTERLY FLOW AHEAD OF A LARGE
DEEP-LAYERED MID-LATITUDE TROUGH CURRENTLY MOVING EASTWARD OFF THE
U.S. EAST COAST. THE NHC FORECAST TRACK IS A LITTLE TO EAST OF THE
PREVIOUS ADVISORY TRACK AFTER 12 HOURS...AND LIES ALONG THE EXTREME
RIGHT SIDE OF THE NHC GUIDANCE ENVELOPE.

THE WINDOW OF OPPORTUNITY FOR GERT TO INTENSIFY IS GRADUALLY COMING
TO A CLOSE. THE CYCLONE WILL BE OVER AT LEAST 26C SSTS FOR ANOTHER
12 HOURS OR SO WHILE THE VERTICAL SHEAR IS STILL LOW. ALTHOUGH THE
OFFICIAL INTENSITY FORECAST ONLY CALLS FOR GERT TO REACH 55 KT...IT
IS POSSIBLE THAT CYCLONE COULD REACH 60 KT BETWEEN THE 12- AND
24-HOUR FORECAST PERIODS DURING THE NOCTURNAL CONVECTIVE MAXIMUM
PERIOD AROUND 12Z TUESDAY MORNING. BY 36 HOURS...GERT WILL BE OVER
NEAR-20C SSTS AND UNDERGOING EXTRATROPICAL TRANSITION. THE
POST-TROPICAL LOW IS THEN FORECAST TO MERGE WITH A FRONTAL SYSTEM
OVER THE FAR NORTH ATLANTIC SHORTLY AFTER 48 HOURS. THE INTENSITY
FORECAST CLOSELY FOLLOWS THE SHIPS AND LGEM MODEL SOLUTIONS...AND
EXTRATROPICAL INTENSITY FORECASTS PROVIDED BY THE NOAA OCEAN
PREDICTION CENTER.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  15/2100Z 33.2N  62.7W   50 KT  60 MPH
 12H  16/0600Z 35.7N  60.8W   55 KT  65 MPH
 24H  16/1800Z 38.9N  57.1W   55 KT  65 MPH
 36H  17/0600Z 41.7N  51.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  17/1800Z 44.6N  45.2W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  18/1800Z...DISSIPATED
 
$$
FORECASTER STEWART
 

WTNT42 KNHC 160231
TCDAT2
 
TROPICAL STORM GERT DISCUSSION NUMBER   9
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072011
1100 PM AST MON AUG 15 2011
 
THE LOW-LEVEL CENTER OF THE TROPICAL CYCLONE APPEARS TO BE NEAR THE
NORTHEASTERN EDGE OF THE MAIN MASS OF DEEP CONVECTION...AND
MICROWAVE DATA SUGGEST SOME NORTHEASTWARD TILT OF THE CENTER WITH
HEIGHT.  DVORAK ESTIMATES OF INTENSITY RANGE FROM 35 TO 55 KT AND
THE CURRENT INTENSITY IS HELD AT 50 KT FOR THIS ADVISORY.  GERT
SHOULD BE TRAVERSING WARM WATER FOR ONLY ANOTHER 12 TO 18 HOURS...
SO WEAKENING IS LIKELY TO COMMENCE IN 24 HOURS...IF NOT SOONER. 
THE OFFICIAL INTENSITY FORECAST IS IN LINE WITH THE STATISTICAL-
DYNAMICAL GUIDANCE.  GLOBAL MODELS SHOW THE SYSTEM BECOMING
EMBEDDED WITHIN A BAROCLINIC ZONE IN 36 HOURS AND BECOMING ABSORBED
BY A LARGE NORTH ATLANTIC LOW IN 2 TO 3 DAYS.  THE OFFICIAL
FORECAST FOLLOWS THIS SCENARIO.

CENTER FIXES HAVE BECOME MORE UNCERTAIN THIS EVENING BUT MY BEST
ESTIMATE IS THAT THERE HAS BEEN AN INCREASE IN FORWARD SPEED AND
THE MOTION IS NOW NEAR 030/16.  GERT IS BEING SWEPT UP IN THE FLOW
AHEAD OF A LARGE TROUGH MOVING OFF THE U.S. EAST COAST.  A GRADUAL
TURN TO THE RIGHT IS ANTICIPATED AS THE CYCLONE MOVES INTO HIGHER
LATITUDES AND BECOMES INFLUENCED BY A MORE ZONAL STEERING CURRENT. 
THD OFFICIAL TRACK FORECAST IS A LITTLE TO THE NORTH OF THE
PREVIOUS ONE AND ON THE SOUTH SIDE OF THE GUIDANCE SUITE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  16/0300Z 34.7N  61.6W   50 KT  60 MPH
 12H  16/1200Z 37.3N  59.6W   50 KT  60 MPH
 24H  17/0000Z 40.8N  55.0W   50 KT  60 MPH
 36H  17/1200Z 44.0N  49.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  18/0000Z 46.5N  41.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  19/0000Z...DISSIPATED
 
$$
FORECASTER PASCH
 

WTNT42 KNHC 160836
TCDAT2
 
TROPICAL STORM GERT DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072011
500 AM AST TUE AUG 16 2011
 
GERT APPEARS TO BE WEAKENING THIS MORNING...WITH THE ASSOCIATED
CLOUD TOPS WARMING AND BECOMING LESS CIRCULAR. IN ADDITION...THE
LOW-LEVEL CENTER HAS BECOME EXPOSED TO THE NORTHEAST OF THE
WEAKENING CONVECTION. THE INITIAL WIND SPEED IS LOWERED TO 40 KT
FOR THIS ADVISORY. A CONTINUED GRADUAL WEAKENING OF GERT IS
EXPECTED AS THE STORM CROSSES THE 26C ISOTHERM LATER THIS MORNING
AND MOVES INTO STRONGER SOUTHWESTERLY SHEAR. GERT IS FORECAST TO
BECOME A POST-TROPICAL CYCLONE IN ABOUT 24 HOURS AS IT MOVES OVER
WATERS NEAR 20C...BUT THIS COULD OCCUR SOONER ESPECIALLY IF THE
CURRENT TREND CONTINUES. WHATEVER IS LEFT OF GERT WILL BE ABSORBED
INTO A FRONT IN A LITTLE OVER 2 DAYS.
 
THE TROPICAL STORM IS ACCELERATING INTO THE NORTH ATLANTIC
WATERS...AND THE LATEST INITIAL MOTION ESTIMATE IS 035/19. AN
ADDITIONAL INCREASE IN FORWARD SPEED AND A GRADUAL TURN TO THE
RIGHT ARE FORECAST AS GERT BECOMES MORE EMBEDDED IN THE STRONG
MID-LATITUDE FLOW TO THE EAST OF A DEEP-LAYER TROUGH ALONG THE
UNITED STATES EAST COAST. THE OFFICIAL FORECAST IS VERY CLOSE TO
THE PREVIOUS ONE AND ON THE EASTWARD SIDE OF THE GUIDANCE ENVELOPE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  16/0900Z 36.4N  59.6W   40 KT  45 MPH
 12H  16/1800Z 38.9N  56.9W   40 KT  45 MPH
 24H  17/0600Z 42.2N  51.7W   35 KT  40 MPH...POST-TROP/EXTRATROP
 36H  17/1800Z 45.4N  45.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
 48H  18/0600Z 48.5N  36.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
 72H  19/0600Z...DISSIPATED
 
$$
FORECASTER CANGIALOSI
 

WTNT42 KNHC 161435
TCDAT2
 
TROPICAL STORM GERT DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072011
ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1100 AM AST TUE AUG 16 2011
 
GERT CONTINUES TO WEAKEN THIS MORNING...WITH THE ASSOCIATED
THUNDERSTORM ACTIVITY VIRTUALLY EVAPORATING AROUND 10Z.  MORNING
SATELLITE IMAGERY...AND TO SOME DEGREE DETERMINISTIC MODEL
GUIDANCE...IMPLIED THAT GERT HAS ABOUT 10 KNOTS OF NORTHEASTERLY
VERTICAL WIND SHEAR DUE TO THE STRONGER SOUTHWESTERLY LOW-LEVEL
FLOW CONFLICTING WITH LIGHTER SOUTHWEST WINDS AT THE 300 HPA LEVEL. 
THE LOW-LEVEL CENTER REMAINS EXPOSED...THOUGH NEW CONVECTION IS
TRYING TO DEVELOP ON ITS NORTHEAST SIDE WHICH COULD BE AN INDICATION
OF A SWITCH IN THE DIRECTION OF THE VERTICAL WIND SHEAR TO
SOUTHWESTERLY...WHICH WAS PREVIOUSLY ANTICIPATED.  THE INITIAL WIND
SPEED HAS BEEN LOWERED TO 35 KT FOR THIS ADVISORY...IN LINE WITH
THE CURRENT T-NUMBER FROM TAFB BUT HIGHER THAN THAT PROVIDED BY
SAB.  THIS SYSTEM STILL HAS A FEW MORE HOURS BEFORE IT CROSSES THE
26C ISOTHERM...WHICH SHOULD ALLOW IT TO RETAIN ITS CURRENT
INTENSITY.  GERT IS FORECAST TO BECOME A POST-TROPICAL CYCLONE IN
ABOUT 12 HOURS AS IT MOVES OVER WATERS NEAR 20C AND INTERACTS WITH
THE APPROACHINIG COLD FRONT...WHICH COULD LEAD TO TEMPORARY
RESTRENGTHENING...SO THE INTENSITY FORECAST HAS BEEN LEFT
RELATIVELY UNCHANGED.  THE RESULTANT LOW PRESSURE AREA SHOULD LOSE
DEFINITION WITHIN THE FRONTAL ZONE DURING THE DAY WEDNESDAY.
 
THE TROPICAL STORM IS ACCELERATING INTO THE NORTH ATLANTIC
WATERS...AND THE LATEST INITIAL MOTION ESTIMATE IS 040/26. THIS
SYSTEM COULD ACCELERATE SLIGHTLY MORE AS GERT BECOMES INCREASINGLY
STEERED BY THE STRONG LOW-LEVEL FLOW TO THE EAST OF A DEEP-LAYER
TROUGH ALONG THE UNITED STATES EAST COAST. THE OFFICIAL FORECAST IS
SLIGHTLY TO THE LEFT OF THE PREVIOUS ONE BUT REMAINS ON THE
EASTWARD SIDE OF THE GUIDANCE ENVELOPE.  THE FORECAST TRACK AND
TIMING OF EXTRATROPICAL TRANSITION INCORPORATE IDEAS COMMUNICATED
BY THE OCEAN PREDICTION CENTER.
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  16/1500Z 38.1N  57.5W   35 KT  40 MPH
 12H  17/0000Z 41.0N  54.2W   35 KT  40 MPH
 24H  17/1200Z 44.3N  49.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 36H  18/0000Z...POST-TROP/EXTRATROP
 
$$
FORECASTER ROTH
 

WTNT42 KNHC 161438
TCDAT2
 
TROPICAL STORM GERT DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072011
ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1100 AM AST TUE AUG 16 2011
 
GERT CONTINUES TO WEAKEN THIS MORNING...WITH THE ASSOCIATED
THUNDERSTORM ACTIVITY VIRTUALLY EVAPORATING AROUND 10Z.  MORNING
SATELLITE IMAGERY...AND TO SOME DEGREE DETERMINISTIC MODEL
GUIDANCE...IMPLIED THAT GERT HAS ABOUT 10 KNOTS OF NORTHEASTERLY
VERTICAL WIND SHEAR DUE TO THE STRONGER SOUTHWESTERLY LOW-LEVEL
FLOW CONFLICTING WITH LIGHTER SOUTHWEST WINDS AT THE 300 HPA LEVEL. 
THE LOW-LEVEL CENTER REMAINS EXPOSED...THOUGH NEW CONVECTION IS
TRYING TO DEVELOP ON ITS NORTHEAST SIDE WHICH COULD BE AN INDICATION
OF A SWITCH IN THE DIRECTION OF THE VERTICAL WIND SHEAR TO
SOUTHWESTERLY...WHICH WAS PREVIOUSLY ANTICIPATED.  THE INITIAL WIND
SPEED HAS BEEN LOWERED TO 35 KT FOR THIS ADVISORY...IN LINE WITH
THE CURRENT T-NUMBER FROM TAFB BUT HIGHER THAN THAT PROVIDED BY
SAB.  THIS SYSTEM STILL HAS A FEW MORE HOURS BEFORE IT CROSSES THE
26C ISOTHERM...WHICH SHOULD ALLOW IT TO RETAIN ITS CURRENT
INTENSITY.  GERT IS FORECAST TO BECOME A POST-TROPICAL CYCLONE IN
ABOUT 12 HOURS AS IT MOVES OVER WATERS NEAR 20C AND INTERACTS WITH
THE APPROACHINIG COLD FRONT...WHICH COULD LEAD TO TEMPORARY
RESTRENGTHENING...SO THE INTENSITY FORECAST HAS BEEN LEFT
RELATIVELY UNCHANGED.  THE RESULTANT LOW PRESSURE AREA SHOULD LOSE
DEFINITION WITHIN THE FRONTAL ZONE DURING THE DAY WEDNESDAY.
 
THE TROPICAL STORM IS ACCELERATING INTO THE NORTH ATLANTIC
WATERS...AND THE LATEST INITIAL MOTION ESTIMATE IS 040/26. THIS
SYSTEM COULD ACCELERATE SLIGHTLY MORE AS GERT BECOMES INCREASINGLY
STEERED BY THE STRONG LOW-LEVEL FLOW TO THE EAST OF A DEEP-LAYER
TROUGH ALONG THE UNITED STATES EAST COAST. THE OFFICIAL FORECAST IS
SLIGHTLY TO THE LEFT OF THE PREVIOUS ONE BUT REMAINS ON THE
EASTWARD SIDE OF THE GUIDANCE ENVELOPE.  THE FORECAST TRACK AND
TIMING OF EXTRATROPICAL TRANSITION INCORPORATE IDEAS COMMUNICATED
BY THE OCEAN PREDICTION CENTER.
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  16/1500Z 38.1N  57.5W   35 KT  40 MPH
 12H  17/0000Z 41.0N  54.2W   35 KT  40 MPH
 24H  17/1200Z 44.3N  49.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 36H  18/0000Z...DISSIPATED
 
$$
FORECASTER ROTH
 

WTNT42 KNHC 161512
TCDAT2
 
TROPICAL STORM GERT DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072011
ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1100 AM AST TUE AUG 16 2011
 
GERT CONTINUES TO WEAKEN THIS MORNING...WITH THE ASSOCIATED
THUNDERSTORM ACTIVITY VIRTUALLY EVAPORATING AROUND 10Z.  MORNING
SATELLITE IMAGERY...AND TO SOME DEGREE DETERMINISTIC MODEL
GUIDANCE...IMPLIED THAT GERT HAS ABOUT 10 KNOTS OF NORTHEASTERLY
VERTICAL WIND SHEAR DUE TO THE STRONGER SOUTHWESTERLY LOW-LEVEL
FLOW CONFLICTING WITH LIGHTER SOUTHWEST WINDS AT THE 300 HPA LEVEL. 
THE LOW-LEVEL CENTER REMAINS EXPOSED...THOUGH NEW CONVECTION IS
TRYING TO DEVELOP ON ITS NORTHEAST SIDE WHICH COULD BE AN INDICATION
OF A SWITCH IN THE DIRECTION OF THE VERTICAL WIND SHEAR TO
SOUTHWESTERLY...WHICH WAS PREVIOUSLY ANTICIPATED.  THE INITIAL WIND
SPEED HAS BEEN LOWERED TO 35 KT FOR THIS ADVISORY...IN LINE WITH
THE CURRENT T-NUMBER FROM TAFB BUT HIGHER THAN THAT PROVIDED BY
SAB.  THIS SYSTEM STILL HAS A FEW MORE HOURS BEFORE IT CROSSES THE
26C ISOTHERM...WHICH SHOULD ALLOW IT TO RETAIN ITS CURRENT
INTENSITY.  GERT IS FORECAST TO BECOME A POST-TROPICAL CYCLONE IN
12-24 HOURS AS IT MOVES OVER WATERS NEAR 20C AND INTERACTS WITH
THE APPROACHINIG COLD FRONT...WHICH COULD LEAD TO TEMPORARY
RESTRENGTHENING...SO THE INTENSITY FORECAST HAS BEEN LEFT
RELATIVELY UNCHANGED.  THE RESULTANT LOW PRESSURE AREA SHOULD LOSE
DEFINITION WITHIN THE FRONTAL ZONE DURING THE DAY WEDNESDAY.
 
THE TROPICAL STORM IS ACCELERATING INTO THE NORTH ATLANTIC
WATERS...AND THE LATEST INITIAL MOTION ESTIMATE IS 040/26. THIS
SYSTEM COULD ACCELERATE SLIGHTLY MORE AS GERT BECOMES INCREASINGLY
STEERED BY THE STRONG LOW-LEVEL FLOW TO THE EAST OF A DEEP-LAYER
TROUGH ALONG THE UNITED STATES EAST COAST. THE OFFICIAL FORECAST IS
SLIGHTLY TO THE LEFT OF THE PREVIOUS ONE BUT REMAINS ON THE
EASTWARD SIDE OF THE GUIDANCE ENVELOPE.  THE FORECAST TRACK AND
TIMING OF EXTRATROPICAL TRANSITION INCORPORATE IDEAS COMMUNICATED
BY THE OCEAN PREDICTION CENTER.
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  16/1500Z 38.1N  57.5W   35 KT  40 MPH
 12H  17/0000Z 41.0N  54.2W   35 KT  40 MPH
 24H  17/1200Z 44.3N  49.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 36H  18/0000Z...DISSIPATED
 
$$
FORECASTER ROTH
 

