[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 190840
TCDAT2
TROPICAL STORM BERYL DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL022006
500 AM EDT WED JUL 19 2006

THE CENTER WOBBLED A BIT TO THE NORTH-NORTHWEST A FEW HOURS AGO BUT
A RECENT FIX FROM THE AIR FORCE HURRICANE HUNTERS INDICATE THAT THE
MOTION IS TOWARD THE NORTH...I.E. 360/6.  A MID-TROPOSPHERIC
SHORTWAVE TROUGH IS CURRENTLY PASSING BY THE LONGITUDE OF BERYL AND
GLOBAL MODELS INDICATE THAT ANOTHER ONE WILL BE APPROACHING THE
SYSTEM IN 36-48 HOURS...WITH A STRONG SUBTROPICAL RIDGE HOLDING IN
PLACE TO THE EAST-SOUTHEAST.  THIS STEERING PATTERN SHOULD CAUSE
THE TROPICAL CYCLONE TO GRADUALLY TURN TOWARD THE NORTHEAST.  THE
OFFICIAL FORECAST TRACK HAS BEEN SHIFTED SOMEWHAT TO THE LEFT FROM
THE PREVIOUS ADVISORY...OUT OF RESPECT FOR A LEFTWARD SHIFT IN THE
GFDL AND GFS TRACKS.  HOWEVER BOTH OF THESE MODELS SHOW A VERY WEAK
SYSTEM IN A COUPLE OF DAYS AND IN FACT THE GFS SUGGEST THAT BERYL
WILL BEGIN TO MERGE WITH AN APPROACHING EXTRATROPICAL CYCLONE IN
2-3 DAYS.  THE OFFICIAL FORECAST IS CLOSEST TO THE U.K. MET. OFFICE
TRACK WHICH APPEARS TO BE A REASONABLE SOLUTION BASED ON THE
STEERING SCENARIO DESCRIBED ABOVE.  BERYL IS LIKELY TO MERGE WITH
THE AFOREMENTIONED MID-LATITUDE SYSTEM BY THE END OF THE FORECAST
PERIOD...IF NOT SOONER.

THE HURRICANE HUNTERS FOUND THE CENTRAL PRESSURE HOLDING STEADY NEAR
1005 MB...AND PEAK 850 MB FLIGHT-LEVEL WINDS WERE 45 KT OVER THE
SOUTHEAST QUADRANT.  THIS JUST SUPPORTS TROPICAL STORM STRENGTH.
SOME DEEP CONVECTION HAS DEVELOPED AROUND THE BROAD CENTER BUT THE
TOPS ARE NOT VERY COLD.  SEA SURFACE TEMPERATURES WILL BE IN 25-27
DEG C RANGE ALONG THE TRACK OF BERYL FOR THE NEXT 24-36 HOURS SO
THERE IS STILL THE POSSIBILITY OF SOME STRENGTHENING.  HOWEVER
ANIMATION OF INFRARED IMAGES SHOW CIRRUS ELEMENTS MOVING
NORTHEASTWARD ACROSS THE CENTER OF THE STORM...INDICATIVE OF
SOUTHWESTERLY SHEAR. GIVEN THE MARGINAL UPPER-LEVEL ENVIRONMENT...A
SUBSTANTIAL INCREASE IN STRENGTH APPEARS UNLIKELY.

THE TROPICAL STORM WATCH FOR THE NORTH CAROLINA COAST IS BEING KEPT
AS A PRECAUTION AT THIS TIME.

FORECAST POSITIONS AND MAX WINDS

INITIAL      19/0900Z 34.7N  73.7W    35 KT
 12HR VT     19/1800Z 35.7N  73.7W    40 KT
 24HR VT     20/0600Z 36.9N  73.7W    45 KT
 36HR VT     20/1800Z 38.6N  72.8W    50 KT
 48HR VT     21/0600Z 40.3N  70.7W    50 KT
 72HR VT     22/0600Z 44.0N  64.0W    45 KT...EXTRATROPICAL
 96HR VT     23/0600Z 47.0N  55.0W    35 KT...EXTRATROPICAL
120HR VT     24/0600Z...MERGED WITH EXTRATROPICAL CYCLONE

$$
FORECASTER PASCH
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