615
WTPZ44 KNHC 010840
TCDEP4
TROPICAL STORM PILAR DISCUSSION NUMBER 15
NWS NATIONAL HURRICANE CENTER MIAMI FL EP192023
400 AM CDT WED NOV 01 2023
DEEP CONVECTION ASSOCIATED WITH PILAR HAS INCREASED OVER THE WESTERN
PORTION OF THE CIRCULATION THIS MORNING. DESPITE SOME CONTINUED
EAST-SOUTHEASTERLY SHEAR OVER THE CYCLONE, THE COLD DENSE OVERCAST
HAS BEGUN TO EXPAND EASTWARD, AND PROXY-VISIBLE AND SHORTWAVE
INFRARED SATELLITE IMAGES SUGGEST THE CENTER IS NO LONGER EXPOSED.
THE LATEST OBJECTIVE INTENSITY ESTIMATES SEEM TOO LOW BASED ON
RECENT SATELLITE TRENDS AND YESTERDAY'S SCATTEROMETER DATA. A BLEND
OF SUBJECTIVE DVORAK CURRENT INTENSITY ESTIMATES FROM SAB AND TAFB
SUPPORT HOLDING THE INITIAL INTENSITY AT 50 KT.
SATELLITE IMAGES AND RECENT FIXES SUGGEST PILAR IS NOW MOVING
NORTHWESTWARD (325/3 KT). A MORE WESTWARD MOTION IS EXPECTED LATER
TODAY, FOLLOWED BY AN ACCELERATION TO THE WEST-SOUTHWEST THROUGH
FRIDAY AS A MID-LEVEL RIDGE BUILDS OVER CENTRAL MEXICO. THIS MOTION
AWAY FROM LAND SHOULD BE REINFORCED BY THE LOW-LEVEL NORTHERLY FLOW
WELL DOWNSTREAM OF A STRONG GULF OF TEHUANTEPEC GAP WIND EVENT. THE
ONLY NOTABLE CHANGE TO THE NHC TRACK FORECAST IS A FASTER FORWARD
SPEED DURING THE FIRST FEW DAYS OF THE FORECAST, WHICH IS SUPPORTED
BY THE LATEST TVCE AND HCCA CONSENSUS AIDS.
WHILE THE SATELLITE STRUCTURE OF PILAR HAS IMPROVED DURING THE
DIURNAL MAXIMUM PERIOD, THE STORM WILL CONTINUE TO BE IMPACTED BY
MODERATE SHEAR DURING THE NEXT COUPLE OF DAYS. ALSO, THE REGIONAL
HURRICANE MODELS SHOW THAT THE SLOW-MOVING CYCLONE HAS UPWELLED SOME
COOLER WATERS, AND PILAR IS FORECAST TO MOVE OVER THIS COOL WAKE
DURING THE NEXT DAY OR TWO. IN ADDITION, MODEL-SIMULATED SATELLITE
IMAGERY INDICATES THE STORM'S CONVECTION COULD BE DISRUPTED WHILE IT
ENCOUNTERS THE DRIER LOW-LEVEL FLOW DOWNSTREAM OF THE ONGOING GAP
WIND EVENT. NOT SURPRISINGLY, MOST OF THE INTENSITY GUIDANCE SHOWS
SOME GRADUAL WEAKENING DURING THE NEXT COUPLE OF DAYS, AND THE
OFFICIAL NHC FORECAST FOLLOWS SUIT. LATER IN THE PERIOD, THERE IS A
LARGE SPREAD IN THE INTENSITY GUIDANCE, AS THE STATISTICAL-DYNAMICAL
AIDS SHOW STRENGTHENING WHILE THE GLOBAL AND REGIONAL HURRICANE
MODELS ARE MUCH WEAKER. SIMILAR TO THE PREVIOUS PREDICTION, THIS
FORECAST STAYS NEAR THE SIMPLE CONSENSUS (IVCN) AND SHOWS LITTLE
INTENSITY CHANGE FROM DAYS 3-5.
KEY MESSAGES:
1. HEAVY RAINS FROM PILAR WILL PRODUCE FLASH AND URBAN FLOODING,
ALONG WITH MUDSLIDES IN AREAS OF HIGHER TERRAIN OF THE PACIFIC COAST
OF CENTRAL AMERICA FROM SOUTHERN EL SALVADOR, ACROSS SOUTHERN
HONDURAS, WESTERN NICARAGUA INTO NORTHERN COSTA RICA THROUGH TODAY.
2. TROPICAL STORM CONDITIONS ARE POSSIBLE ALONG PORTIONS OF THE
PACIFIC COAST OF EL SALVADOR, HONDURAS, AND NICARAGUA, WHERE A
TROPICAL STORM WATCH REMAINS IN EFFECT.
3. SWELLS GENERATED BY PILAR WILL CONTINUE TO AFFECT THE PACIFIC
COAST OF CENTRAL AMERICA DURING THE NEXT COUPLE OF DAYS. THESE
SWELLS ARE LIKELY TO CAUSE LIFE-THREATENING SURF AND RIP CURRENT
CONDITIONS.
FORECAST POSITIONS AND MAX WINDS
INIT 01/0900Z 12.3N 89.9W 50 KT 60 MPH
12H 01/1800Z 12.1N 90.6W 50 KT 60 MPH
24H 02/0600Z 11.7N 92.5W 45 KT 50 MPH
36H 02/1800Z 11.0N 95.2W 45 KT 50 MPH
48H 03/0600Z 10.2N 98.1W 40 KT 45 MPH
60H 03/1800Z 9.6N 101.0W 40 KT 45 MPH
72H 04/0600Z 9.2N 103.5W 40 KT 45 MPH
96H 05/0600Z 9.5N 108.5W 40 KT 45 MPH
120H 06/0600Z 10.0N 111.5W 35 KT 40 MPH
FORECASTER REINHART
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