Example - Tropical Cyclone Discussion

000
WTNT43 KNHC 212040
TCDAT3

HURRICANE BILL DISCUSSION NUMBER  26
NWS NATIONAL HURRICANE CENTER MIAMI FL   AL032009
500 PM AST FRI AUG 21 2009
 
AN AIR FORCE HURRICANE HUNTER AIRCRAFT REACHED BILL THIS
AFTERNOON AND FOUND THAT THE CENTRAL PRESSURE HAS REMAINED AROUND
954 MB...BUT THE WINDS HAVE DECREASED AND INITIAL INTENSITY IS NOW
90 KT. THE PLANE REPORTED A SMALL EYE OF 14 N MI DIAMETER.
GIVEN THE CONCENTRIC RING STRUCTURE OBSERVED ON MICROWAVE AND THE
DOUBLE WIND MAXIMA PROVIDED BY THE PLANE...IT IS LIKELY THAT THE
HURRICANE IS GOING THROUGH AN EYEWALL REPLACEMENT AND THE REASON
FOR THE CURRENT WEAKENING. THERE IS AN OPPORTUNITY FOR BILL TO
REGAIN SOME STRENGTH DURING THE NEXT 12 TO 24 HOURS WHILE THE SHEAR
IS LOW AND BEFORE THE HURRICANE REACHES COOLER WATERS.
THEREAFTER...A STEADY WEAKENING IS INDICATED AND BY 72 HOURS...BILL
SHOULD ALREADY BE AN EXTRATROPICAL CYCLONE INTERACTING WITH THE
HIGH LATITUDE WESTERLIES.
 
BILL IS NOW MOVING TOWARD THE NORTH-NORTHWEST OR 340 DEGREES AT 17
KNOTS. THE HURRICANE SHOULD GRADUALLY TURN MORE TO THE NORTH AROUND
THE BERMUDA-AZORES HIGH TONIGHT AND SATURDAY AND SHOULD BE FORCED TO
RECURVE AS A LARGE MID-LATITUDE TROUGH MOVES EASTWARD ACROSS THE
EASTERN UNITED STATES.  THERE HAS NOT BEEN ANY CHANGE IN TRACK
GUIDANCE WHICH IN FACT CONTINUES TO BE TIGHTLY PACKED...MAINTAINING
HIGH CONFIDENCE IN THE TRACK FORECAST.
 
LARGE SWELLS GENERATED BY THIS HURRICANE WILL AFFECT A LARGE PORTION
OF THE WESTERN NORTH ATLANTIC COASTAL AREA DURING THE NEXT FEW
DAYS.  THESE SWELLS WILL LIKELY CAUSE EXTREMELY DANGEROUS SURF AND
LIFE-THREATENING RIP CURRENTS.  PLEASE CONSULT STATEMENTS ISSUED BY
YOUR LOCAL WEATHER OFFICE AND METEOROLOGICAL SERVICES FOR MORE
DETAILS.
 
AT THIS TIME...TROPICAL-STORM-FORCE WINDS ARE NOT FORECAST TO REACH
NEW ENGLAND.  HOWEVER...A SLIGHT SHIFT OF THE FORECAST TRACK TO THE
LEFT WOULD REQUIRE A TROPICAL STORM WATCH OR WARNING TONIGHT.  THE
WIND SPEED PROBABILITY PRODUCT INDICATES THAT THERE IS ROUGHLY A 25
PERCENT CHANCE OF THESE WINDS REACHING EXTREME SOUTHEASTERN NEW
ENGLAND.
 
FORECAST POSITIONS AND MAX WINDS

INIT  13/0900Z 20.5N  86.0W   80 KT  90 MPH
 12H  13/1800Z 21.2N  85.9W   90 KT 105 MPH
 24H  14/0600Z 22.0N  85.7W   95 KT 110 MPH
 36H  14/1800Z 22.8N  85.6W  100 KT 115 MPH
 48H  15/0600Z 23.7N  85.5W  105 KT 120 MPH
 72H  16/0600Z 25.4N  85.2W  115 KT 135 MPH
 96H  17/0600Z 27.1N  85.0W  120 KT 140 MPH
120H  18/0600Z 28.8N  84.7W  105 KT 120 MPH 
 
$$
FORECASTER AVILA