TROPICAL WEATHER DISCUSSION
TUESDAY - 9/26/00 - 7:00 A.M.
HURRICANE ISAAC:
LITTLE CHANGE IN THINKING FOR ISAAC.
ISAAC CONTINUES A SLOW & STEADY W.N.W. MOTION AS HE HAS BEEN FOR DAYS. HE WILL BE REACHING THE ERODING WESTERN
EDGE OF THE SUBTROPICAL RIDGE WITHIN 72 HOURS AS A TROF MOVES OFF THE EAST COAST. SO, AS WAS MY THINKING
YESTERDAY RECURVATURE WITHIN A FEW DEGREES OF 60 WEST STILL LOOKS GOOD THIS MORNING. CURRENT THINKING IS
ISAAC WILL PASS SOME 150 TO 250 MILES TO THE EAST OF BERMUDA. THIS WILL LEAVE BERMUDA ON THE WEAKER SIDE OF THE CYCLONE. HOWEVER, DEPENDING ON EXACT
TRACK BERMUDA COULD EXPERIENCE TROPICAL STORM FORCE WINDS AND SQUALLS. WE WILL HAVE TO WAIT ANOTHER 48 - 72 HOURS TO GET A HANDLE ON EXACTLY HOW OR IF BERMUDA WILL BE AFFECTED.
NO MATTER WHAT, SWELLS AND ROUGH SURF ARE LIKELY FOR BERMUDA.
INTENSITY: FIRST VISIBLE PIC OF THE MORNING SHOW THAT SHEAR IS TAKING SOMEWHAT OF A TOLL ON ISAAC. THERE IS
VIRTUALLY NO OUTFLOW ON THE SOUTHERN SEMICIRCLE OF THE CYCLONE. A GOOD CDO IS PRESENT AND INFLOW ON ALL QUADS
REMAINS GOOD. I THINK TPC 5AM INTENSITY IS LIKELY A BIT HIGH...BUT NOT MUCH AND ISAAC AS OF THIS HOUR LOOKS LIKE
A 95-100 MPH HURRICANE. I WOULD EXPECT INTENSITY IN THE 90-100 MPH RANGE NEXT 60 OR SO HOURS...THEN CONDITIONS
IMPROVE AND AS RECURVATURE BEGINS IN ABOUT 72 HOURS INTENSITY COULD GO BACK UP TO 115 MPH. BEYOND THAT A GRADUAL
WEAKENING TREND IS EXPECTED AS ISAAC EVENTUALLY MOVES OVER COLDER WATER...BUT THAT IS 5-6 DAYS AWAY....HE WILL BE
ON THE MAPS RIGHT INTO THE VERY EARLY PART OF NEXT WEEK.
JOYCE:
JOYCE LOOKS VERY DISORGANIZED ON THE FIRST VISIBLE PICS OF THE DAY. AT BEST SHE IS A MINIMAL T.S.
MY THINKING ON JOYCE HAS ALSO CHANGED LITTLE LAST 24 HOURS. A GENERAL WEST (270-275) TRACK AT A SLOW FORWARD
SPEED IS LIKELY NEXT 72 HOURS...VERY MUCH LIKE LATEST OFFICIAL TPC FCST.
INTENSITY: I THINK TPC INTENSITY FCST IS TOO AGGRESSIVE AND I WOULD EXPECT ONLY VERY SLOW OR NO DEVELOPMENT FOR
48-72 HOURS. BEYOND 72 HOURS AS THE DISTANCE BETWEEN ISAAC AND JOYCE BECOME GREATER AND ATMOSPHERIC CONDITIONS
ALOFT AROUND JOYCE IMPROVE SHE SHOULD BE FREE TO INTENSIFY. BUT, FOR THE NEXT 2-3 DAYS SHE WILL BE STRUGGLING AND I REALLY DON'T EXPECT A MARKED CHANGE IN INTENSITY UNTIL AT LEAST BEYOND 48 HOURS AND MORE LIKELY OUT TO 72 HOURS.
TRACK: AS MENTIONED ABOVE...GENERAL WEST TRACK NEXT 3 DAYS. BEYOND THAT A TRACK TOWARD THE CENTRAL OR MORE
LIKELY NORTHERN ISLANDS SEEMS LIKELY. I DO THINK JOYCE WILL IMPACT THE ISLANDS....BIG QUESTION IS (AS ALWAYS) HOW STRONG A SYSTEM WILL SHE BE?? BEYOND THE ISLANDS THREAT IT IS WAY TO EARLY TO CALL FOR POSSIBLE IMPACT ON THE U.S
.... BUT AT THIS EARLY POINT IN TIME I CAN'T RULE IT OUT. BASED ON MAJORITY OF LARGE SCALE GLOBAL MODELS ODDS WOULD FAVOR
AN IMPACT OVER NO IMPACT BUT THAT IS A LONG WAY OUT.
ELSEWHERE....CONVECTION OVER THE CARIBBEAN HAS GREATLY DIMINISHED. MRF ON THE OTHER HAND STILL PULLS SOMETHING
NORTH OUT OF THE CARIBBEAN TO VCTY FLORIDA THEN NORTH UP THE EAST COAST AS STRONG HIGH PRESSURE BRIDGES TO THE
NORTH. THE CONSEQUENCES OF THIS WOULD BE LARGE AS WINDS TO GALE OR STORM FORCE WOULD LAST THE ENTIRE EAST COAST.
THE MRF HAS HAD THIS SCENARIO FOR DAYS AND DAYS AND HAS NOT BACKED DOWN TODAY.
BASED ON THE FACT THAT CONVECTION IN THE CARIBBEAN THIS MORNING IS NIL AND I FEEL THE MRF IS OVER DEEPENING THE TROF
IN THE EAST BY THE WEEKEND AND EARLY NEXT WEEK THIS EXTREME SOLUTION IN DISREGARDED AND NO TROPICAL CYCLONE
FORMATION IS EXPECTED IN THE CARIBBEAN NEXT FEW DAYS.
HOWEVER, EVEN IF WEAK LOW PRESSURE FORMS ALONG A FRONT OFF THE S.E. COAST LATER IN THE WEEK THE GRADIENT ALONG THE
COAST COULD REALLY TIGHTEN UP TO CAUSE SOME STRONG WINDS. THIS POSSIBILITY NEEDS TO BE WATCHED OUT FOR. EVEN
WITHOUT THE PRESENCE OF DEVELOPING LOW PRESSURE THE WINDS FROM NORTH CAROLINA TO FLORIDA WILL BE STRONG FROM THE
EAST AND SOME MINOR BEACH EROSION IS POSSIBLE. THIS STRONG ONSHORE FLOW IS COURTESY OF STRONG/BROAD HIGH PRESSURE
CRESTING OVER THE NORTHEAST.
BOTTOM LINE: ISAAC IS NO THREAT TO LAND EXCEPT FOR SOME POSSIBLE IMPACT ON BERMUDA IN ABOUT 5 DAYS. JOYCE IS
EXPECTED TO ONLY VERY SLOWLY DEVELOP AS SHE HEADS WEST...EVENTUALLY TO POST THREAT TO ISLANDS. NO TROPICAL
STORM DEVELOPMENT IS EXPECTED IN THE CARIBBEAN. BRISK ONSHORE WINDS LIKELY FROM NC TO FL AROUND STRONG HIGH
PRESSURE TO THE NORTH. WATCHING FOR POSSIBLE LOW FORMATION OFF S.E. COAST TO INCREASE WIND THREAT BUT THAT IS
JUST SPECULATION AT THIS POINT.
WILL UPDATE AGAIN TOMORROW MORNING.
THIS INFORMATION IN NO WAY SHOULD BE USED IN PLACE OF OFFICIAL INFORMATION FROM LOCAL EMS/NWS...IT IS INTENDED TO INFORM READERS OF MY OPINIONS ONLY. IF ORDERED TO EVACUATE...PLEASE DO SO! PLEASE MAKE DECISIONS BASED ON INFORMATION SUPPLIED BY LOCAL EMS/NWS OFFICIALS. NO RESPONSIBILITY WRITTEN OR IMPLIED ON USE OF THIS PRODUCT.