Tropical Storm NORMA
ZCZC MIATCDEP4 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM NORMA DISCUSSION NUMBER 15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 AM PDT MON SEP 26 2005
DEEP CONVECTION HAS DECREASED SIGNIFICANTLY OVER THE PAST SEVERAL
HOURS...AND IS NOW OCCURRING IN ONLY A FEW PATCHES NEAR THE CENTER
AND OVER PARTS THE SOUTHERN SEMICIRCLE OF THE CIRCULATION. THIS
DECREASE IS LIKELY DUE TO A COMBINATION OF COOLER SEA SURFACE
TEMPERATURES AND MORE STABLE LAPSE RATES. EASTERLY SHEAR CONTINUES
TO BE AN INHIBITING INFLUENCE AS WELL. NORMA APPEARS TO BE
WEAKENING MORE RAPIDLY THAN EARLIER FORECAST...BUT IT REMAINS TO BE
SEEN WHETHER THE DEEP CONVECTION WILL MAKE A SUBSTANTIAL COMEBACK.
IF THIS DOES NOT OCCUR...THE SYSTEM COULD DISSIPATE EVEN SOONER
THAN SHOWN IN THE FORECAST. GIVEN THE CURRENT DOWNWARD TREND...THE
OFFICIAL INTENSITY FORECAST IS A LITTLE BELOW THE LATEST SHIPS AND
GFDL GUIDANCE.
INITIAL MOTION...310/7...IS ABOUT THE SAME AS IN THE PREVIOUS
ADVISORY...AS IS THE TRACK FORECAST. A LARGE MID-TROPOSPHERIC HIGH
PRESSURE SYSTEM CENTERED NEAR THE WESTERN TEXAS-MEXICO BORDER
CONTINUES TO STEER NORMA NORTHWESTWARD. THE TROPICAL CYCLONE
SHOULD GRADUALLY TURN TOWARD THE WEST DURING THE NEXT COUPLE OF
DAYS AS THE MID-LEVEL RIDGE DEVELOPS WESTWARD AND TO THE NORTH OF
NORMA. IN 3-5 DAYS...THE PRIMARY STEERING INFLUENCE SHOULD BE THE
EAST-NORTHEASTERLY TRADE FLOW ASSOCIATED WITH A SUBTROPICAL HIGH
CENTERED TO THE NORTHWEST OF NORMA'S REMNANT LOW.
FORECASTER PASCH
FORECAST POSITIONS AND MAX WINDS
INITIAL 26/1500Z 19.6N 114.2W 35 KT
12HR VT 27/0000Z 20.2N 115.0W 35 KT
24HR VT 27/1200Z 21.0N 116.1W 30 KT
36HR VT 28/0000Z 21.2N 117.1W 25 KT...DISSIPATING
48HR VT 28/1200Z 21.0N 118.2W 20 KT...REMNANT LOW
72HR VT 29/1200Z 20.5N 120.0W 20 KT...REMNANT LOW
96HR VT 30/1200Z 20.0N 122.0W 20 KT...REMNANT LOW
120HR VT 01/1200Z 20.0N 124.0W 20 KT...REMNANT LOW
$$
NNNN