452
WTPZ44 KNHC 311444
TCDEP4
TROPICAL STORM PILAR DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL EP192023
1000 AM CDT TUE OCT 31 2023
PILAR'S STRUCTURE HAS CHANGED LITTLE SINCE LAST NIGHT. GOES-16
ONE-MINUTE VISIBLE SATELLITE IMAGERY SHOWS THAT THE CENTER IS
EXPOSED TO THE SOUTHEAST OF THE MAIN CONVECTIVE MASS, WITH SOME
BANDING NOTED OVER THE FAR NORTHEASTERN PORTION OF THE CIRCULATION.
SUBJECTIVE DVORAK SATELLITE ESTIMATES FROM BOTH TAFB AND SAB WERE
T3.0 OR 45 KT AT 1200 UTC, AND THE INITIAL INTENSITY REMAINS AT
THAT VALUE FOR THIS ADVISORY.
PILAR IS STILL MOVING SLOWLY EASTWARD OR 090/3 KT. THE STORM IS
FORECAST TO STALL LATER TODAY AS THE STEERING CURRENT OVER THE FAR
EASTERN PACIFIC COLLAPSE. ON WEDNESDAY, A NARROW MID-LEVEL
RIDGE IS FORECAST TO BUILD TO THE NORTH AND NORTHEAST OF PILAR
WHICH SHOULD CAUSE THE STORM TO BEGIN MOVING WEST-SOUTHWESTWARD. A
WEST-SOUTHWESTWARD TO WESTWARD MOTION IS THEN EXPECTED INTO THE
WEEKEND AS THE RIDGE BUILDS WESTWARD TO THE NORTH OF THE STORM. THE
LATEST NHC TRACK FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND
IS A BLEND OF THE THE ECMWF, GFS, AND THE LATEST CONSENSUS AIDS.
THE TROPICAL STORM WATCH FOR PORTIONS OF CENTRAL AMERICA REMAINS IN
EFFECT, BUT GIVEN THE LATEST MODEL TRENDS IT COULD BE DISCONTINUED
LATER TODAY OR THIS EVENING. ALTHOUGH THE THREAT OF TROPICAL-STORM-
FORCE WINDS APPEARS TO BE DIMINISHING, THE RISK OF HEAVY RAIN AND
FLASH FLOODING IS EXPECTED TO CONTINUE OVER PORTIONS OF CENTRAL
AMERICA DURING THE NEXT COUPLE OF DAYS.
SOME SLIGHT STRENGTHENING IS POSSIBLE DURING THE NEXT DAY OR SO
AS THE STORM IS LOCATED WITHIN MODERATE VERTICAL WIND SHEAR AND
OVER WARM SEA SURFACE TEMPERATURES. HOWEVER, THE LATEST NHC
FORECAST CALLS FOR A LITTLE LESS INTENSIFICATION DURING THIS TIME
THAN BEFORE. AS PILAR MOVES WESTWARD THE SHEAR COULD RELAX, BUT
INTRUSIONS OF DRY AIR FROM A GAP WIND EVENT ARE LIKELY TO HOLD THE
INTENSITY IN CHECK. VERY LATE IN THE PERIOD, THE INTENSITY GUIDANCE
SUGGESTS THAT ENVIRONMENTAL CONDITIONS COULD BECOME A LITTLE MORE
CONDUCIVE TO SUPPORT SOME STRENGTHENING DURING THE WEEKEND, AND THE
NHC WIND SPEED FORECAST HAS BEEN ADJUSTED ACCORDINGLY.
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
WEDNESDAY.
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 FEW DAYS. THESE SWELLS ARE
LIKELY TO CAUSE LIFE-THREATENING SURF AND RIP CURRENT CONDITIONS.
FORECAST POSITIONS AND MAX WINDS
INIT 31/1500Z 11.2N 89.9W 45 KT 50 MPH
12H 01/0000Z 11.5N 89.8W 50 KT 60 MPH
24H 01/1200Z 11.7N 90.2W 50 KT 60 MPH
36H 02/0000Z 11.5N 91.4W 50 KT 60 MPH
48H 02/1200Z 11.1N 93.4W 45 KT 50 MPH
60H 03/0000Z 10.5N 95.8W 45 KT 50 MPH
72H 03/1200Z 9.9N 98.5W 45 KT 50 MPH
96H 04/1200Z 9.4N 103.8W 45 KT 50 MPH
120H 05/1200Z 9.8N 108.7W 50 KT 60 MPH
FORECASTER BROWN
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