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Tropical Storm MATTHEW (Text)

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TROPICAL STORM MATTHEW DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL152010
500 PM EDT THU SEP 23 2010
 
AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT INVESTIGATING THE
CYCLONE FOUND 42-KT FLIGHT-LEVEL WINDS AT ABOUT 1500 FT IN THE
NORTHEAST QUADRANT ON ITS OUTBOUND LEG. THAT WIND SPEED WOULD
NORMALLY EQUATE TO ABOUT 34 KT AT THE SURFACE. ALSO...THERE WERE
SEVERAL BELIEVABLE SFMR SURFACE WINDS OF 35-37 KT IN THAT AREA.
SINCE THOSE WIND REPORTS...CONVECTIVE BANDING HAS CONTINUED TO
INCREASE AND BECOME BETTER ORGANIZED..AND THE DEPRESSION HAS BEEN
UPGRADED TO TROPICAL STORM MATTHEW.
 
THE INITIAL MOTION ESTIMATE IS 280/14. TROPICAL STORM MATTHEW IS
EXPECTED TO MOVE WEST TO WEST-NORTHWESTWARD FOR THE NEXT 48 HOURS
OR SO...AND PASS OVER OR NEAR THE NORTHERN COASTS OF NICARAGUA AND
HONDURAS IN 36-48 HOURS. AFTER THAT...THE GLOBAL MODELS DIFFER ON
THE TIMING OF THE WEAKENING OF THE SUBTROPICAL RIDGE OVER THE
NORTHWESTERN CARIBBEAN SEA AND THE GULF OF MEXICO. A STRONG
MID-LATITUDE TROUGH CURRENTLY OFF THE U.S. WEST COAST IS FORECAST
TO MOVE QUICKLY EASTWARD INTO THE CENTRAL U.S. BY DAY 3...THE
TROUGH IS FORECAST TO DIG SOUTHEASTWARD AND AMPLIFY INTO A LOW
PRESSURE SYSTEM OVER THE SOUTHEASTERN U.S. AND THE GULF OF MEXICO.
EROSION OF THE SUBTROPICAL RIDGE TO THE NORTH OF MATTHEW IS
EXPECTED TO CAUSE THE STEERING CURRENTS TO COLLAPSE ACROSS THE
NORTHWESTERN CARIBBEAN SEA AND THE YUCATAN PENINSULA. ALL OF THE
NHC MODELS ARE CONSISTENT ON THE EVOLUTION OF THIS SYNOPTIC
SCALE PATTERN...EXCEPT FOR THE TIMING. THE GFS...ECMWF...NOGAPS...
HWRF...AND GFDL MODELS KEEP THE LOW WEST OF 85W LONGITUDE BY 120
HOURS...WHEREAS THE UKMET IS MUCH MORE PROGRESSIVE AND MOVES THE
LARGE TROUGH EAST OF 80W. GIVEN THE USUAL SLOW MOVEMENT OF SUCH
A HIGH AMPLITUDE TROUGH...THE UKMET IS CONSIDERED AN OUTLIER MODEL
AT THIS TIME. AS A RESULT...THE OFFICIAL FORECAST TRACK IS A BLEND
OF THE GLOBAL AND REGIONAL MODELS...EXCLUDING THE UKMET SOLUTION...
AND IS JUST AN UPDATE OF THE PREVIOUS FORECAST TRACK.
 
STEADY INTENSIFICATION IS EXPECTED THROUGH 72 HOURS SINCE MATTHEW
WILL BE MOVING OVER 30C SSTS AND BENEATH A REGION OF UPPER-LEVEL
ANTICYCLONIC FLOW. MATTHEW IS EXPECTED TO MOVE OVER OR NEAR THE
NORTH COAST OF HONDURAS IN 36-48 HOURS...AND MOVE INLAND NEAR
BELIZE BY DAY 4. LAND INTERACTION WOULD DISRUPT THE INTENSIFICATION
PROCESS DESPITE THE OTHERWISE FAVORABLE ENVIRONMENTAL CONDITIONS.
HOWEVER...IF THE CYCLONE REMAINS OVER WATER...THEN MATTHEW COULD
EASILY REACH HURRICANE STRENGTH DURING THE NEXT 48 HOURS AND
BEYOND. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS
ADVISORY AND THE SHIPS/LGEM MODELS...AND IS BASED ON THE ASSUMPTION
THAT MATTHEW WILL MOVE INLAND AFTER 72 HOURS.

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      23/2100Z 14.0N  76.9W    35 KT
 12HR VT     24/0600Z 14.4N  78.9W    40 KT
 24HR VT     24/1800Z 15.1N  81.7W    50 KT
 36HR VT     25/0600Z 15.6N  84.0W    60 KT...INLAND
 48HR VT     25/1800Z 16.2N  85.8W    60 KT...OVER WATER
 72HR VT     26/1800Z 17.1N  88.0W    70 KT
 96HR VT     27/1800Z 18.3N  88.4W    70 KT...INLAND
120HR VT     28/1800Z 19.5N  87.5W    70 KT...INLAND
 
$$
FORECASTER STEWART
 
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