[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 070252
TCDAT5

TROPICAL STORM ERNESTO DISCUSSION NUMBER  22
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052012
1100 PM EDT MON AUG 06 2012

DURING THE PAST SEVERAL HOURS...THE INNER CORE CONVECTION OF ERNESTO
HAS TAKEN A BEATING DUE TO MID-LEVEL DRY AIR ENTRAINMENT. ONLY A
SMALL CONVECTIVE CLUSTER EXISTS OVER THE LOW-LEVEL CENTER...WHILE
THE REST OF THE SIGNIFICANT CONVECTION IS OCCURRING MORE THAN 100
NMI NORTHEAST THROUGH SOUTHEAST OF THE CENTER. DESPITE THE
CONVECTIVE EROSION...AN AIR FORCE RESERVE RECON AIRCRAFT HAS FOUND
THAT THE INNER CORE WIND FIELD REMAINS RATHER TIGHT WITH A RADIUS
OF 12-15 NMI. THE STRONGEST 850 MB FLIGHT-LEVEL WIND OBSERVED THUS
FAR HAS BEEN 61 KT IN THE NORTHEAST QUADRANT AND THE HIGHEST
RAIN-ADJUSTED SFMR SURFACE WIND MEASURED HAS BEEN 46 KT. GIVEN THAT
THE RECON FOUND A SURFACE PRESSURE OF ABOUT 994 MB...WHICH IS CLOSE
TO THE PREVIOUS ADVISORY PRESSURE...THE INITIAL INTENSITY WILL
REMAIN AT 55 KT UNTIL THE AIRCRAFT COMPLETES ITS MISSION.

INITIAL MOTION ESTIMATE IS 300/11. THE NHC MODEL GUIDANCE REMAINS IN
EXCELLENT AGREEMENT THAT ERNESTO WILL MOVE IN A WEST-NORTHWESTWARD
DIRECTION FOR THE NEXT 24-36 HOURS AND MAKE LANDFALL IN ABOUT 30
HOURS NEAR THE COASTS OF NORTHERN BELIZE AND THE SOUTHERN YUCATAN
PENINSULA. AFTER LANDFALL OCCURS...A WEAK SUBTROPICAL RIDGE OVER
THE NORTHERN GULF OF MEXICO THAT EXTENDS FROM TEXAS EASTWARD TO
FLORIDA IS EXPECTED TO STEER THE CYCLONE WESTWARD ACROSS THE BAY OF
CAMPECHE...BUT AT A SLOWER FORWARD SPEED. THE OFFICIAL FORECAST
TRACK IS CLOSE TO THE PREVIOUS ADVISORY AND IS SIMILAR TO THE
TIGHTLY PACKED CONSENSUS MODELS TVCA AND TV15.

CONDITIONS ARE FAVORABLE FOR RAPID INTENSIFICATION TO OCCUR...EXCEPT
FOR THE LACK OF INNER-CORE DEEP CONVECTION. EVEN THOUGH RECON DATA
INDICATE ERNESTO STILL HAS A TIGHT INNER-CORE WIND FIELD...DRY AIR
THAT HAS WRAPPED WELL INTO THE CENTER WILL LIKELY PREVENT ANY
STRONG CENTRAL CONVECTION FROM BEING ABLE TO PERSIST NEAR THE
LOW-LEVEL CENTER. HOWEVER...SINCE ERNESTO WILL BE MOVING OVER SSTS
ABOUT 1C WARMER AND INTO EVEN A WEAKER SHEAR ENVIRONMENT IN ABOUT
18-24 HOURS...THESE FAVORABLE CONDITIONS SHOULD ALLOW FOR AT LEAST
SOME MODEST STRENGTHENING TO OCCUR...AND ERNESTO COULD STILL BECOME
A HURRICANE BEFORE IT MAKES LANDFALL. THE OFFICIAL INTENSITY
FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY...FOLLOWS THE
INTENSITY CONSENSUS MODEL IV15 UNTIL LANDFALL...AND IS CLOSE TO A
BLEND OF THE DECAY-SHIPS AND LGEM MODELS AFTER THAT.

FORECAST POSITIONS AND MAX WINDS

INIT  07/0300Z 17.0N  82.7W   55 KT  65 MPH
 12H  07/1200Z 17.5N  84.3W   60 KT  70 MPH
 24H  08/0000Z 18.3N  86.8W   70 KT  80 MPH
 36H  08/1200Z 18.9N  89.0W   45 KT  50 MPH...INLAND OVER YUCATAN
 48H  09/0000Z 19.3N  91.1W   35 KT  40 MPH...OVER WATER
 72H  10/0000Z 19.5N  94.8W   60 KT  70 MPH
 96H  11/0000Z 19.4N  97.4W   50 KT  60 MPH...INLAND
120H  12/0000Z 19.2N  99.4W   20 KT  25 MPH...DISSIPATING INLAND

$$
FORECASTER STEWART


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