744
WTPZ44 KNHC 010239
TCDEP4
TROPICAL STORM PILAR DISCUSSION NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL EP192023
1000 PM CDT TUE OCT 31 2023
AFTER THE PREVIOUS ADVISORY, A SIGNIFICANT CONVECTIVE BURST FORMED
MAINLY TO THE WEST OF THE CENTER OF PILAR THAT IS NOW WANING.
WHILE THE MOST RECENT GPM MICROWAVE PASS MISSED THE CENTER OF
THE STORM, IT DID CATCH A PROMINENT CURVED BAND ON THE 37-GHZ
CHANNEL EXTENDING TO THE NORTHWEST AWAY FROM THE CENTER. SUBJECTIVE
DVORAK ESTIMATES WERE T3.0/45 KT FROM TAFB AND T3.5/55 KT FROM SAB.
TAKING A BLEND OF THESE ESTIMATES, THE INITIAL INTENSITY IS SET AT
50 KT THIS ADVISORY. THIS VALUE ALSO ASSUMES A BIT OF UNDERSAMPLING
FROM THE ASCAT-B/C PASSES THAT HAD PEAK WIND RETRIEVALS OF 45 KT
OUTSIDE OF THE CONVECTION EARLIER TODAY. WHILE THE WIND-RADII WERE
ADJUSTED A BIT BASED ON THAT SCATTEROMETER DATA, THE 34-KT WINDS
REMAIN JUST OFFSHORE OF EL SALVADOR.
PILAR HAS NUDGED A BIT CLOSER TO THE COAST OF EL SALVADOR, WITH THE
ESTIMATED MOTION A DRIFT TO THE NORTH AT 360/2 KT. THE UPPER-LEVEL
TROUGH THAT HAD WEAKENED THE RIDGING OVER MEXICO IS LIFTING OUT, AND
IN RESPONSE, MID-LEVEL RIDGING IS BECOMING RE-ESTABLISHED OVER
MEXICO. IN ADDITION, A SIGNIFICANT GALE-FORCE GAP WIND EVENT IS
CURRENTLY ONGOING TO THE WEST OF PILAR IN THE GULF OF TEHUANTEPEC. A
COMBINATION OF THESE LOW AND MID-LEVEL STEERING INFLUENCES IS
EXPECTED TO START MOVING PILAR TO THE WEST AND THEN WEST-SOUTHWEST
BEGINNING TOMORROW AND CONTINUING THROUGH THE END OF THIS WEEK. THE
TRACK GUIDANCE REMAINS IN FAIRLY GOOD AGREEMENT ON THIS SOLUTION,
THOUGH WAS A BIT FURTHER NORTH EARLY ON GIVEN THE INITIAL POSITION,
AND FURTHER SOUTH TOWARDS THE END OF THE FORECAST. THE NHC TRACK HAS
BEEN ADJUSTED ACCORDINGLY, AND STILL LIES IN BETWEEN THE RELIABLE
TVCE AND HCCA CONSENSUS AIDS.
PILAR COULD BE NEAR ITS PEAK INTENSITY AS IT CONTINUES TO BATTLE
MODERATE VERTICAL WIND SHEAR OUT OF THE EAST. WHILE THIS SHEAR IS
FORECAST TO DECREASE IN THE NEXT 24-48 HOURS, THIS IS EXPECTED TO BE
OFFSET BY OCEAN UPWELLING, WHICH IS LIKELY OCCURRING NEAR THE SLOW
MOVING STORM CURRENTLY, IN ADDITION TO THE STRONG GAP-WIND FLOW
FURTHER WEST ALSO PUTTING A DENT IN THE SEA-SURFACE TEMPERATURES
ALONG PILAR'S FORECAST TRACK. THIS EFFECT IS MOST ACCURATELY
CAPTURED BY THE ATMOSPHERIC-OCEAN COUPLED HURRICANE REGIONAL
GUIDANCE, WHICH ARE ALL NOTABLY LOWER THAN THE CONSENSUS AIDS AS
THEY SHOW PILAR TRAVERSING SSTS BELOW 26 C OVER THE NEXT FEW DAYS.
THE AFOREMENTIONED GAP WINDS MAY ALSO IMPORT DRY MID-LATITUDE AIR
NEAR THE CIRCULATION OF PILAR AS IT BEGINS TO LOSE LATITUDE. THE
MOST RECENT GFS AND ECMWF RUNS ALSO SHOW A WEAKER SYSTEM THAN BEFORE
AFTER THE NEXT 36-48 HOURS, SO A BIT MORE WEAKENING IS SHOWN IN THE
LATEST NHC FORECAST. THIS FORECAST SPLITS THE DIFFERENCE BETWEEN THE
HIGHER IVCN AND HCCA CONSENSUS AIDS, AND THE LOWER HURRICANE
REGIONAL MODEL GUIDANCE.
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 01/0300Z 11.9N 89.4W 50 KT 60 MPH
12H 01/1200Z 11.9N 89.5W 50 KT 60 MPH
24H 02/0000Z 11.7N 91.0W 50 KT 60 MPH
36H 02/1200Z 11.3N 93.2W 45 KT 50 MPH
48H 03/0000Z 10.6N 96.0W 40 KT 45 MPH
60H 03/1200Z 9.8N 98.9W 40 KT 45 MPH
72H 04/0000Z 9.4N 101.4W 40 KT 45 MPH
96H 05/0000Z 9.0N 106.0W 40 KT 45 MPH
120H 06/0000Z 10.0N 110.0W 40 KT 45 MPH
FORECASTER PAPIN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page