WTPZ42 KNHC 250842 RRA

TCDEP2



TROPICAL STORM OTTO DISCUSSION NUMBER  18...CORRECTED

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP222016

300 AM CST FRI NOV 25 2016



CORRECTED FOR CENTRAL STANDARD TIME INSTEAD OF CENTRAL DAYLIGHT

TIME IN PRODUCT HEADER.



THE CLOUD PATTERN OF OTTO IS RATHER RAGGED THIS MORNING AFTER THE

CIRCULATION MOVED OFFSHORE OF CENTRAL AMERICA. SHORTWAVE INFRARED

IMAGERY SUGGESTS THAT THERE MAY NOW BE SOME TILT TO THE CIRCULATION,

WITH THE LOW-LEVEL CENTER POSSIBLY LOCATED SOUTH OF THE MID-LEVEL

CENTER. HOWEVER, THIS IS QUITE UNCERTAIN GIVEN THE LACK OF MICROWAVE

IMAGERY OVERNIGHT. BASED ON THIS APPARENT DECREASE IN ORGANIZATION,

THE INITIAL INTENSITY IS SET TO 50 KT, A LITTLE BELOW THE LATEST

DVORAK ESTIMATES OF T3.5/55 KT FROM TAFB AND SAB.



THE INTENSITY FORECAST IS PROBLEMATIC. MOST OF THE GUIDANCE SUGGESTS

THAT OTTO WILL MAINTAIN ITS CURRENT INTENSITY FOR THE NEXT 48 HOURS

OR SO WHILE THE CYCLONE MOVES OVER SSTS OF 28-29C BUT WITH

CONTINUED SOUTHEASTERLY SHEAR OF 15-20 KT. THROUGH THIS TIME THE

NHC INTENSITY FORECAST IS NEAR OR A BIT BELOW THE IVCN INTENSITY

CONSENSUS. BY DAY 3, THE SHEAR BEGINS TO DECREASE, BUT THE

ATMOSPHERE DRIES OUT AS OTTO INTERACTS WITH OUTFLOW FROM A GULF OF

TEHUANTEPEC GAP WIND EVENT. THE GLOBAL MODELS SHOW OTTO WEAKENING

LATE IN THE PERIOD, AND THAT TREND IS REFLECTED IN THE OFFICIAL

FORECAST, WHICH CONTINUES TO SHOW OTTO BECOMING A REMNANT LOW AT DAY

5. HOWEVER, GIVEN THE UNCERTAINTY IN THE CURRENT STRUCTURE OF OTTO

AND THE INTERPLAY BETWEEN SEVERAL COMPETING ENVIRONMENTAL FACTORS

DURING THE FORECAST PERIOD, CONFIDENCE IN THE INTENSITY FORECAST IS

LOWER THAN USUAL.=