WTPZ44 KNHC 200859 RRA

TCDEP4



TROPICAL DEPRESSION TWENTY-FOUR-E DISCUSSION NUMBER   2

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP242018

400 AM CDT SAT OCT 20 2018



VARIOUS SATELLITE DATA INDICATE THAT THE AREA OF LOW PRESSURE THAT

NHC HAS BEEN MONITORING OFF THE COAST OF SOUTHERN MEXICO FOR THEW

PAST FEW DAYS HAS ACQUIRED ENOUGH CONVECTIVE ORGANIZATION TO BE

DESIGNATED AS A TROPICAL DEPRESSION, THE TWENTY-FOURTH ONE OF THE

VERY BUSY 2018 EASTERN NORTH PACIFIC HURRICANE SEASON. ALTHOUGH THE

DEPRESSION IS A SHEARED SYSTEM, SOME BANDING FEATURES HAVE RECENTLY

DEVELOPED SOUTH OF THE CENTER, WHILE OVERSHOOTING CLOUD TOPS JUST

WEST OF THE CENTER ARE QUITE COLD -85 TO -91 DEG C). THE INITIAL

INTENSITY IS SET TO 30 KT BASED ON A SATELLITE INTENSITY ESTIMATE OF

T2.0/30 KT FROM BOTH TAFB AND SAB.



THE INITIAL MOTION ESTIMATE IS 280/08 KT, BASED PRIMARILY ON PASSIVE

MICROWAVE FIXES AND GOES-16 NIGHTTIME IMAGERY. A GRADUAL TURN TOWARD

THE WEST-NORTHWEST IS EXPECTED BY THIS AFTERNOON, FOLLOWED BY A

SLOWER NORTHWESTWARD MOTION ON SUNDAY AS THE SYSTEM MOVES ALONG THE

SOUTHWESTERN PERIPHERY OF A WEAKENING MID-LEVEL RIDGE. A SLOW

NORTHWESTWARD MOTION IS EXPECTED TO CONTINUE INTO EARLY NEXT WEEK

WHILE THE RIDGE TO THE NORTH CHANGES LITTLE.  ON DAYS 4 AND 5,

HOWEVER, A SERIES OF WEAK SHORTWAVE TROUGHS ARE FORECAST TO MOVE

THROUGH THE LARGER SCALE SOUTHWESTERLY FLOW LOCKED IN OVER THE

SOUTHWESTERN U.S. AND NORTHERN MEXICO, CAUSING AN EROSION OF THE

WESTERN PORTION OF THE RIDGE, WHICH SHOULD ALLOW THE CYCLONE TO

GRADUALLY RECURVE NORTHWARD AND NORTH-NORTHEASTWARD. THE NHC MODEL

GUIDANCE IS IN GOOD AGREEMENT OVERALL ON THIS DEVELOPING TRACK