Flhurricane.com - Central Florida Hurricane Center - Tracking Storms since 1995Hurricanes Without the Hype! Since 1995
The Atlantic is quiet
|
Show Selection: |
| #549742 (Received by flhurricane at: 4:58 AM 13.Oct.2012) TCDAT2 TROPICAL STORM RAFAEL DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL172012 500 AM AST SAT OCT 13 2012 RAFAEL CONTINUES TO HAVE A DISHEVELED APPEARANCE IN SATELLITE IMAGERY. WHILE THE TROPICAL CYCLONE IS MAINTAINING A LARGE CLOUD SHIELD...DEEP CONVECTION CONTINUES TO BE DISPLACED EAST OF THE LOW-LEVEL CENTER DUE TO PERSISTENT STRONG SOUTHWESTERLY SHEAR. HOWEVER...CONVECTION HAS BEEN INCREASING IN INTENSITY AND COVERAGE IN A BAND SOUTHEAST OF THE CENTER DURING THE PAST SEVERAL HOURS. MAXIMUM FLIGHT-LEVEL WINDS REPORTED BY AN AIR FORCE PLANE FLYING AT 5000 FT WERE 40 KT AND PEAK SFMR WINDS WERE BETWEEN 35-40 KT...THOUGH SEVERAL OF THE HIGHER VALUES COULD BE RAIN CONTAMINATED. BASED ON THESE DATA...THE INITIAL INTENSITY IS KEPT AT 35 KT. RAFAEL APPEARS TO HAVE MOVED TO THE LEFT OF THE PREVIOUS ESTIMATE... WITH THE LONG-TERM AVERAGE MOTION STILL TOWARD THE NORTHWEST OR 320/08. IN THE SHORT TERM...THE CYCLONE IS EXPECTED TO BE STEERED SLOWLY POLEWARD INTO A BREAK IN THE SUBTROPICAL RIDGE CREATED BY A MID-LATITUDE SHORTWAVE PASSING THROUGH ATLANTIC CANADA. BETWEEN 36-72 HOURS...THE TRACK GUIDANCE SHOWS RAFAEL JOGGING TOWARD THE NORTHWEST OR EVEN WEST-NORTHWEST AS A LOW- TO MID-LEVEL RIDGE TEMPORARILY BUILDS TO THE NORTH OF THE STORM. BY DAY 3...A COMPLEX BUT PROGRESSIVE SHORTWAVE OVER EASTERN NORTH AMERICA SHOULD CAUSE RAFAEL TO RECURVE INTO THE WESTERLIES...FOLLOWED BY A NORTHEASTWARD ACCELERATION. WHILE THE CROSS-TRACK SPREAD OF THE MODEL GUIDANCE IS GENERALLY MINIMAL...THE ALONG-TRACK SPREAD IS RATHER SUBSTANTIAL. ON ONE END OF THE SPECTRUM IS THE GFS WHICH MAINTAINS A STRONGER REPRESENTATION OF RAFAEL THAT IS CAPTURED BY THE ABOVE- MENTIONED SHORTWAVE. THE ECMWF AND UKMET...ON THE OTHER HAND...HAVE WEAKER VERSIONS OF THE STORM THAT ARE STEERED MORE SLOWLY NORTHEASTWARD BY A WEAKER SHORTWAVE IN THE SOUTHERN STREAM. THE NHC TRACK FORECAST IS ADJUSTED TO THE LEFT AND IS SLOWER THAN THE PREVIOUS ONE AS A RESULT OF SOME WEIGHT GIVEN TO THE ECMWF/UKMET SOLUTIONS. THERE IS GREATER-THAN-NORMAL UNCERTAINTY WITH REGARD TO THE INTENSITY FORECAST. SOUTHWESTERLY SHEAR AFFECTING RAFAEL IS FORECAST TO DECREASE DURING THE NEXT 24 HOURS AS THE COLD LOW NORTHWEST OF THE CYCLONE SHEARS OUT. THIS COULD ALLOW FOR A PERIOD OF INTENSIFICATION FOR A DAY OR TWO...THOUGH THE ECMWF SHOWS ENOUGH SOUTHWESTERLY SHEAR CONTINUING TO PRECLUDE MUCH STRENGTHENING. REGARDLESS OF THAT...ALL MODELS SHOW INCREASING SHEAR AFTER 72 HOURS AS WESTERLY FLOW INCREASES AHEAD OF THE SHORTWAVE MOVING INTO THE WESTERN ATLANTIC AROUND THAT TIME. DESPITE THIS...HWRF...GFDL...AND SHIPS MODELS CONTINUE TO SHOW RAFAEL REACHING HURRICANE STRENGTH. THE INTENSITY FORECAST IS INCREASED A BIT OVER THE PREVIOUS ONE...AND IS CLOSE TO THE INTENSITY CONSENSUS AIDS. EXTRATROPICAL TRANSITION IS INDICATED AT DAY 5 IN AGREEMENT WITH GLOBAL MODEL OUTPUT. FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 15.7N 64.2W 35 KT 40 MPH 12H 13/1800Z 17.0N 64.5W 40 KT 45 MPH 24H 14/0600Z 18.8N 65.1W 45 KT 50 MPH 36H 14/1800Z 20.5N 65.8W 50 KT 60 MPH 48H 15/0600Z 22.2N 66.8W 60 KT 70 MPH 72H 16/0600Z 26.4N 67.0W 60 KT 70 MPH 96H 17/0600Z 35.8N 62.9W 60 KT 70 MPH 120H 18/0600Z 45.0N 56.0W 50 KT 60 MPH...POST-TROP/EXTRATROP $$ FORECASTER KIMBERLAIN/AVILA |
