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Tropical Storm ANDRES (Text)

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TROPICAL STORM ANDRES DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP022009
800 AM PDT MON JUN 22 2009
 
A TRMM MICROWAVE PASS AT 1035 UTC SHOWED THAT THE CENTER OF ANDRES
WAS LOCATED NORTHEAST OF THE EXPECTED POSITION. OVERALL...ANDRES
APPEARS TO BE A LITTLE BETTER ORGANIZED...WITH VERY DEEP CONVECTION
NEAR THE CENTER AND A MORE SYMMETRIC OUTFLOW AND CONVECTIVE
PATTERN. THE INITIAL INTENSITY WILL BE HELD AT 45 KT IN ACCORDANCE
WITH THE LATEST DVORAK ESTIMATES FROM TAFB/SAB. 

THE BEST ESTIMATE OF INITIAL MOTION IS 330/04...USING THE TRMM AND
QUIKSCAT MICROWAVE FIXES FROM OVERNIGHT. WATER VAPOR IMAGES
INDICATE THAT UPPER TROUGH OVER MEXICO IS JUST NORTH OF ANDRES AND
THIS FEATURE MAY HAVE HELPED STEER THE SYSTEM MORE NORTHWARD THAN
EXPECTED. HOWEVER...THE GLOBAL MODELS SHOW THIS TROUGH WEAKENING
AND MOVING NORTHWARD WITH TIME AS RIDGING BUILDS OVER MEXICO. THE
EXACT TIMING OF THESE EVENTS IS CRITICAL TO WHETHER ANDRES WILL
MOVE NORTHWESTWARD NEAR THE COAST OF THE MEXICO FOR THE NEXT DAY OR
TWO OR MOVE ONSHORE. THE OFFICIAL FORECAST HAS BEEN SHIFTED TO THE
NORTHEAST AND NOW SHOWS THE CENTER OF ANDRES MOVING VERY CLOSE TO
THE MEXICAN COAST. 

THE INTENSITY FORECAST THIS MORNING IS TRICKY WITH THE TRACK
FORECAST EDGING CLOSER TO LAND. WHILE ANDRES REMAINS UNDER THE
INFLUENCE OF WARM SSTS AND LIGHT TO MODERATE EASTERLY SHEAR...
STRENGTHENING IS LIKELY. IN A DAY OR SO...THE PROXIMITY OF THE
TROPICAL CYCLONE TO LAND MAY INHIBIT FURTHER INTENSIFICATION. IN A
COUPLE OF DAYS...ANDRES WILL BEGIN TO FEEL THE EFFECTS OF COOLER
SSTS SOUTH OF BAJA CALIFORNIA AND MORE STABLE AIR...CAUSING MORE
SIGNIFICANT WEAKENING. MOST OF THE INTENSITY GUIDANCE DOES NOT SHOW
AS MUCH STRENGTHENING AS BEFORE...PROBABLY BECAUSE OF THE
INCREASING LIKELIHOOD OF SIGNIFICANT LAND INTERACTION. LITTLE
CHANGE TO THE PREVIOUS NHC FORECAST IS SHOWN AT THIS TIME. 
HOWEVER...IF THE CENTER MOVES ANY FARTHER TO THE NORTHEAST...ANDRES
COULD WEAKEN SIGNIFICANTLY MORE THAN FORECAST IN A COUPLE OF DAYS.  
 
ALTHOUGH THE OFFICIAL FORECAST TRACK DOES NOT EXPLICITLY
INDICATE LANDFALL...IT IS CLOSE ENOUGH TO THE COAST THAT A TROPICAL
STORM WARNING AND A HURRICANE WATCH ARE NOW REQUIRED FOR PORTIONS
OF SOUTHWESTERN MEXICO.  
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      22/1500Z 16.0N 102.0W    45 KT
 12HR VT     23/0000Z 16.7N 102.5W    55 KT
 24HR VT     23/1200Z 17.8N 103.4W    60 KT
 36HR VT     24/0000Z 19.0N 104.7W    65 KT
 48HR VT     24/1200Z 20.0N 106.0W    60 KT
 72HR VT     25/1200Z 21.5N 108.5W    50 KT
 96HR VT     26/1200Z 22.0N 111.5W    40 KT
120HR VT     27/1200Z 22.0N 116.0W    25 KT...REMNANT LOW
 
$$
FORECASTER BLAKE/BRENNAN
 
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