484
WTPZ44 KNHC 310839
TCDEP4
TROPICAL STORM PILAR DISCUSSION NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL EP192023
400 AM CDT TUE OCT 31 2023
WHILE DEEP CONVECTION HAS INCREASED WITH PILAR OVERNIGHT, THE
CENTER OF THE STORM REMAINS MOSTLY EXPOSED ON THE SOUTHEASTERN
SIDE OF A BURST OF DEEP CONVECTION. IT SEEMS LIKE MODERATE SHEAR
IS PREVENTING THE SYSTEM FROM STRENGTHENING, WITH BASICALLY NO
THUNDERSTORM ACTIVITY SOUTHEAST OF THE CENTER. THE INITIAL WIND
SPEED REMAINS 45 KT BASED ON A BLEND OF THE AVAILABLE INTENSITY
ESTIMATES.
PILAR CONTINUES TO CREEP EAST-NORTHEASTWARD, OR 075/3 KT, A LITTLE
SLOWER THAN THE PREVIOUS ADVISORY. THE STEERING FLOW IS EXPECTED TO
COLLAPSE LATER TODAY, WITH MOST OF THE GUIDANCE STALLING PILAR JUST
EAST OF 90W, THEN ACCELERATING THE STORM WEST-SOUTHWESTWARD AS A
MID-LEVEL RIDGE BUILDS BY THURSDAY. GENERALLY, THE MODEL GUIDANCE
STAYS A TOUCH FARTHER OFFSHORE THAN THE LAST CYCLE, AND THE OFFICIAL
FORECAST FOLLOWS THE TREND. LITTLE CHANGE WAS MADE AT LONG RANGE,
WITH THE PREVIOUS FORECAST COMING IN VERY CLOSE TO THE MODEL
CONSENSUS. IT IS POSSIBLE THAT LATER TODAY THE TROPICAL STORM WATCH
COULD BE DISCONTINUED FOR PORTIONS OF CENTRAL AMERICA, BUT THERE
REMAINS A SIGNIFICANT HEAVY RAIN AND FLASH FLOODING THREAT.
THE STORM STILL HAS A CHANCE TO INTENSIFY OVER THE NEXT DAY OR SO
WITHIN MODERATE WIND SHEAR CONDITIONS BUT IN A MOIST AND UNSTABLE
AIR MASS ALONG WITH WARM OCEAN WATERS. IT SEEMS LIKE THE CHANCES OF
PILAR BECOMING A HURRICANE HAVE DECREASED, AND THE PEAK NHC WIND
SPEED FORECAST IS DROPPED 5 KT FROM THE PREVIOUS ONE, SLIGHTLY ABOVE
THE MODEL CONSENSUS. IT REMAINS TO BE SEEN HOW PILAR MAINTAINS
ITSELF IN A CHALLENGING ENVIRONMENT AFTER 60 HOURS, WITH DRY AIR
INTRUSIONS FROM A GAP WIND EVENT AND EASTERLY WIND SHEAR. THE
INTENSITY FORECAST IS MAINTAINED AT 45 KT AT LONG RANGE, BLENDING
RELIABLE GUIDANCE SHOWING TROPICAL DEPRESSION TO HURRICANE STRENGTH,
AND THE UNCERTAINTY IS HIGH AT LONG RANGE.
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 EL SALVADOR SOUTHWARD TO COSTA RICA THROUGH
WEDNESDAY.
2. TROPICAL STORM CONDITIONS ARE POSSIBLE BEGINNING LATER TODAY
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 31/0900Z 11.4N 90.4W 45 KT 50 MPH
12H 31/1800Z 11.6N 89.9W 50 KT 60 MPH
24H 01/0600Z 11.8N 89.9W 55 KT 65 MPH
36H 01/1800Z 11.7N 90.6W 55 KT 65 MPH
48H 02/0600Z 11.3N 92.1W 50 KT 60 MPH
60H 02/1800Z 10.7N 94.3W 45 KT 50 MPH
72H 03/0600Z 10.1N 97.0W 45 KT 50 MPH
96H 04/0600Z 9.2N 102.5W 45 KT 50 MPH
120H 05/0600Z 9.5N 108.0W 45 KT 50 MPH
FORECASTER BLAKE
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