874 
 WTNT45 KNHC 241457
 TCDAT5
 TROPICAL STORM MATTHEW DISCUSSION NUMBER   5
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL152010
 1100 AM EDT FRI SEP 24 2010
  
 AN AIR FORCE PLANE INVESTIGATING MATTHEW THIS MORNING FOUND THAT THE
 TROPICAL CYCLONE HAS NOT BECOME ANY STRONGER. EASTERLY SHEAR HAS
 KEPT THE LOW-LEVEL CENTER NEAR THE NORTHEAST EDGE OF A ROUND BLOB
 OF VERY DEEP CONVECTION AS INDICATED BY THE AIR FORCE PLANE AND
 MICROWAVE DATA. SATELLITE INTENSITY ESTIMATES SUPPORT AN INITIAL
 INTENSITY OF 45 KNOTS...BUT DATA FROM THE RECONNAISSANCE PLANE SO
 FAR SUGGEST THAT THIS ESTIMATE COULD BE GENEROUS. MATTHEW ONLY HAS
 12 HOURS OR LESS TO STRENGTHEN BEFORE LANDFALL...AND GIVEN THAT THE
 ENVIRONMENT IS ONLY MARGINALLY FAVORABLE FOR INTENSIFICATION DUE TO
 SHEAR...THE OFFICIAL FORECAST NO LONGER FORECAST MATTHEW TO BECOME
 A HURRICANE.
  
 THE CYCLONE HAS INCREASED ITS FORWARD SPEED AND THE BEST ESTIMATE OF
 THE INITIAL MOTION IS TOWARD THE WEST OR 275 DEGREES AT 17 KNOTS.
 MATTHEW IS EMBEDDED WITHIN A STRONG DEEP EASTERLY FLOW AND THERE IS
 HIGH CONFIDENCE IN THE FORECAST THAT THE CYCLONE WILL CONTINUE
 WESTWARD OVER CENTRAL AMERICA FOR THE NEXT DAY OR TWO.  BEYOND TWO
 DAYS...MODELS SHOW DIFFERENT SCENARIOS AND THE FORECAST BECOMES
 HIGHLY UNCERTAIN. THE MOST LIKELY SCENARIO IS THAT THE MID-LEVEL
 CENTER CONTINUES WESTWARD AND DISSIPATES...WHILE THE LOW-LEVEL
 CIRCULATION WEAKENS AND BECOMES PART OF A NEARLY STATIONARY BROAD
 AREA OF LOW PRESSURE OVER CENTRAL AMERICA. SUCH A WEATHER PATTERN
 WOULD LIKELY PRODUCE DANGEROUS TORRENTIAL RAINS IN CENTRAL AMERICA
 OVER THE NEXT FEW DAYS.
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      24/1500Z 14.4N  82.2W    45 KT
  12HR VT     25/0000Z 14.6N  84.2W    35 KT...INLAND
  24HR VT     25/1200Z 15.4N  86.5W    30 KT...INLAND
  36HR VT     26/0000Z 16.0N  89.0W    30 KT...INLAND
  48HR VT     26/1200Z 17.0N  90.0W    25 KT...INLAND
  72HR VT     27/1200Z 18.0N  90.5W    20 KT...POST-TROP/REMNT LOW
  96HR VT     28/1200Z 18.5N  90.5W    20 KT...POST-TROP/REMNT LOW
 120HR VT     29/1200Z 18.5N  90.5W    20 KT...POST-TROP/REMNT LOW
  
 $$
 FORECASTER AVILA