000
WTPZ44 KNHC 240238
TCDEP4
TROPICAL STORM FRANK DISCUSSION NUMBER  10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP092010
800 PM PDT MON AUG 23 2010
 
AFTER APPEARING RATHER RAGGED EARLIER TODAY...DEEP CONVECTION HAS
REDEVELOPED AND PERSISTED OVER THE CENTER OF FRANK DURING THE PAST
SEVERAL HOURS.  DVORAK SATELLITE ESTIMATES FROM TAFB AND SAB SUPPORT
MAINTAINING AN INITIAL INTENSITY OF 45 KT.  THE SHIPS MODEL
DIAGNOSES ABOUT 20-25 KT OF EASTERLY SHEAR OVER FRANK.  THE SHEAR
IS NOT EXPECTED TO ABATE DURING THE NEXT 12-24 HOURS. THEREAFTER...
THE SHEAR IS FORECAST TO DECREASE A LITTLE...BUT REMAIN AROUND 15
KT UNTIL THE CYCLONE APPROACHES COOLER WATER IN 3-4 DAYS. SINCE THE
UPPER-LEVEL ENVIRONMENT IS NOT EXPECTED TO BECOME CONDUCIVE FOR
SIGNIFICANT STRENGTHENING...THE NEW OFFICIAL FORECAST HAS BEEN
ADJUSTED DOWNWARD FROM THE PREVIOUS ADVISORY.  THE OFFICIAL
FORECAST IS IN BEST AGREEMENT WITH THE GFDL MODEL THROUGH 36
HOURS...AND IS CLOSE TO A GFDL/SHIPS/LGEM CONSENSUS THEREAFTER.
 
FRANK HAS BEEN MOVING WEST-NORTHWESTWARD OR 290/8 KT.  THE TRACK
FORECAST REASONING IS UNCHANGED FROM BEFORE.  A DEEP-LAYER RIDGE
OVER WESTERN NORTH AMERICA IS FORECAST TO KEEP THE CYCLONE ON A
GENERAL WEST-NORTHWESTWARD HEADING THROUGHOUT THE FORECAST PERIOD.
THIS MOTION SHOULD KEEP FRANK ON A TRACK PARALLEL TO THE SOUTHERN
AND SOUTHWESTERN COAST OF MEXICO.  THE TRACK GUIDANCE IS IN GOOD
AGREEMENT ON THIS SCENARIO AND THE CONFIDENCE IN THE TRACK FORECAST
IS HIGHER THAN YESTERDAY.  THE NEW TRACK FORECAST IS VERY CLOSE TO
THE PREVIOUS ADVISORY AND THE TVCN CONSENSUS.

SINCE FRANK IS NOT EXPECTED TO GROW SIGNIFICANTLY LARGER IN SIZE
AND THERE IS NOW HIGHER CONFIDENCE IN THE TRACK FORECAST...THE
CHANCES OF TROPICAL STORM FORCE WINDS OCCURRING ALONG THE COAST OF
SOUTHERN MEXICO HAVE DECREASED.  THEREFORE...THE GOVERNMENT OF
MEXICO HAS REPLACED THE TROPICAL STORM WARNING WITH A TROPICAL
STORM WATCH.
 
ONSHORE MONSOONAL SOUTHWESTERLY FLOW WELL TO THE EAST OF FRANK IS
PRODUCING LOCALLY HEAVY RAINFALL OVER PORTIONS OF SOUTHEASTERN
MEXICO.  THESE RAINS...WHILE NOT DIRECTLY ATTRIBUTABLE TO
FRANK...COULD CONTINUE FOR ANOTHER COUPLE OF DAYS.
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      24/0300Z 15.2N 100.1W    45 KT
 12HR VT     24/1200Z 15.6N 101.3W    50 KT
 24HR VT     25/0000Z 16.2N 102.8W    50 KT
 36HR VT     25/1200Z 16.9N 104.5W    55 KT
 48HR VT     26/0000Z 17.7N 106.2W    55 KT
 72HR VT     27/0000Z 18.8N 109.0W    60 KT
 96HR VT     28/0000Z 19.8N 111.5W    55 KT
120HR VT     29/0000Z 20.5N 113.0W    45 KT
 
$$
FORECASTER BROWN