000
WTNT44 KNHC 182038
TCDAT4
 
TROPICAL STORM HUMBERTO DISCUSSION NUMBER  34
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL092013
500 PM AST WED SEP 18 2013

CONVECTION HAS INCREASED A LITTLE NEAR THE CENTER OF HUMBERTO...
MAINLY IN SKELETAL BANDS IN THE NORTHEASTERN SEMICIRCLE.  WATER
VAPOR AND AIRMASS IMAGERY SHOWS THAT THE LOW-LEVEL CENTER IS STILL
IN CLOSE PROXIMITY TO AN UPPER-LEVEL LOW...AND THIS MAY BE SLOWING
THE DEVELOPMENT OF THE CENTRAL CONVECTION.  RECENT OSCAT DATA
SHOWED A FEW 30-35 KT WIND VECTORS ABOUT 150 N MI FROM THE CENTER
IN THE EASTERN SEMICIRCLE.  IN ADDITION...RECENT AMSU INTENSITY
ESTIMATES FROM CIRA AND CIMSS ARE 37 KT AND 32 KT RESPECTIVELY. 
BASED ON THESE DATA...THE INITIAL INTENSITY REMAINS A POSSIBLY
GENEROUS 35 KT.

HUMBERTO HAS MADE ITS EXPECTED NORTHWARD TURN WITH THE INITIAL
MOTION NOW 355/5.  THE SYSTEM IS EXPECTED TO CONTINUE NORTHWARD
DURING THE NEXT 12 HOURS OR SO...FOLLOWED BY AN ACCELERATION TOWARD
THE NORTH-NORTHEAST AS THE CYCLONE ENTERS THE WESTERLIES.  THE
TRACK MODEL GUIDANCE REMAINS TIGHTLY CLUSTERED...AND THE NEW TRACK
FORECAST IS AGAIN SIMILAR TO THE PREVIOUS FORECAST.
 
THERE IS STILL TIME FOR HUMBERTO TO STRENGTHEN SOME AS IT MOVES INTO
A MORE FAVORABLE UPPER-LEVEL WIND ENVIRONMENT NORTH OF THE
UPPER-LEVEL LOW.  THE CYCLONE SHOULD APPROACH A FRONTAL ZONE IN
36-48 HOURS.  HOWEVER...THE MODELS ARE IN POOR AGREEMENT ON WHETHER
HUMBERTO WILL UNDERGO EXTRATROPICAL TRANSITION...OR WHETHER IT WILL
DEGENERATE TO A TROUGH AS ANOTHER LOW BECOMES THE PREDOMINANT
SYSTEM.  THE INTENSITY FORECAST FOLLOWS THE PREVIOUS FORECAST IN
CALLING FOR HUMBERTO TO BECOME EXTRATROPICAL IN 48 HOURS.  THAT
BEING SAID...REGARDLESS OF THE EXACT EVOLUTION THERE IS LIKELY TO
BE A STORM-FORCE EXTRATROPICAL LOW NEAR THE 72 HOUR POINT.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  18/2100Z 31.8N  43.7W   35 KT  40 MPH
 12H  19/0600Z 33.0N  43.6W   35 KT  40 MPH
 24H  19/1800Z 34.9N  42.9W   40 KT  45 MPH
 36H  20/0600Z 37.4N  41.0W   40 KT  45 MPH
 48H  20/1800Z 41.6N  37.1W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  21/1800Z 54.0N  23.5W   50 KT  60 MPH...POST-TROP/EXTRATROP
 96H  22/1800Z...ABSORBED BY EXTRATROPICAL LOW
 
$$
FORECASTER BEVEN