Tropical Storm PRISCILLA
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TROPICAL STORM PRISCILLA DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL EP162013
200 AM PDT MON OCT 14 2013
SATELLITE AND MICROWAVE DATA SHOW THAT THE AREA OF LOW PRESSURE
LOCATED WELL SOUTHWEST OF THE SOUTHERN TIP OF THE BAJA CALIFORNIA
PENINSULA HAS ACQUIRED ENOUGH ORGANIZED DEEP CONVECTION TO BE
CLASSIFIED AS A TROPICAL CYCLONE. IN ADDITION...A COUPLE OF ASCAT
PASSES AND SHIP OBSERVATIONS FROM THE RESEARCH VESSEL MELVILLE...
INDICATE THAT THE SYSTEM HAS MAXIMUM WINDS OF 35 KT. AS A
RESULT...ADVISORIES ARE BEING INITIATED ON TROPICAL STORM
PRISCILLA...THE SIXTEENTH TROPICAL STORM OF THE SEASON IN THE
EASTERN NORTH PACIFIC BASIN.
OVERNIGHT SATELLITE FIXES SHOW THAT THE CYCLONE HAS BEEN MOVING
NORTH-NORTHEASTWARD AT A FASTER RATE THAN WAS OBSERVED DURING THE
DAY YESTERDAY...HOWEVER THE INITIAL MOTION OF 015/10 KT IS A BIT
MORE UNCERTAIN THAN NORMAL. PRISCILLA SHOULD MOVE NORTH-
NORTHEASTWARD TO NORTHWARD DURING THE NEXT DAY OR TWO AS IT MOVES
AROUND THE WESTERN PORTION OF A MID-LEVEL RIDGE OVER MEXICO. IN A
COUPLE OF DAYS...THE RIDGE IS FORECAST TO WEAKEN WHICH SHOULD CAUSE
THE CYCLONE TO SLOW DOWN AND TURN NORTHWESTWARD. AS PRISCILLA
WEAKENS AND BECOMES A SHALLOWER CYCLONE LATER IN THE PERIOD...IT IS
EXPECTED TO SLOW DOWN WITHIN AN AREA OF WEAK LOW-LEVEL STEERING
FLOW WELL WEST-SOUTHWEST OF THE BAJA CALIFORNIA PENINSULA.
PRISCILLA IS A SHEARED TROPICAL CYCLONE WITH THE CENTER LOCATED NEAR
THE NORTHEASTERN EDGE OF THE CONVECTIVE MASS. EAST-NORTHEASTERLY
SHEAR IS FORECAST TO CONTINUE OVER THE CYCLONE DURING THE NEXT 24
HOURS...BUT SOME SLIGHT STRENGTHENING IS POSSIBLE DURING THAT TIME.
ALTHOUGH THE VERTICAL SHEAR OVER PRISCILLA IS FORECAST TO DECREASE
IN 36 TO 48 HOURS...THE CYCLONE WILL BE APPROACHING COOL WATERS AND
A MORE STABLE AIRMASS. THIS SHOULD RESULT IN GRADUAL WEAKENING
BY 48 HOURS...AND PRISCILLA IS EXPECTED TO DEGENERATE INTO A
REMNANT LOW WITHIN 3 TO 4 DAYS.
FORECAST POSITIONS AND MAX WINDS
INIT 14/0900Z 14.3N 115.7W 35 KT 40 MPH
12H 14/1800Z 15.8N 115.2W 40 KT 45 MPH
24H 15/0600Z 17.0N 115.1W 45 KT 50 MPH
36H 15/1800Z 18.1N 115.1W 45 KT 50 MPH
48H 16/0600Z 19.2N 115.7W 40 KT 45 MPH
72H 17/0600Z 20.5N 116.5W 30 KT 35 MPH
96H 18/0600Z 21.0N 117.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 19/0600Z 21.0N 118.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
$$
FORECASTER BROWN
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