700
WTPZ44 KNHC 030836
TCDEP4
TROPICAL STORM PILAR DISCUSSION NUMBER 23
NWS NATIONAL HURRICANE CENTER MIAMI FL EP192023
400 AM CDT FRI NOV 03 2023
DEEP CONVECTION OVER THE CENTER OF PILAR HAS COLLAPSED THIS MORNING.
THE LOW-LEVEL CIRCULATION OF THE COMPACT STORM IS EXPOSED, AND ONLY
SMALL AREAS OF CONVECTIVE ACTIVITY ARE NOTED WELL AWAY FROM THE
CENTER. THESE CHANGES ARE LIKELY THE RESULT OF SOME DRY AIR
INTRUSIONS AND WESTERLY SHEAR OVER THE SMALL CYCLONE. GIVEN ITS
LACKLUSTER SATELLITE PRESENTATION, AND ITS INCREASED DISTANCE FROM
THE ENHANCED BACKGROUND FLOW ASSOCIATED WITH A GAP WIND EVENT, IT IS
ASSUMED THAT SOME WEAKENING HAS OCCURRED OVERNIGHT. THUS, THE
INITIAL INTENSITY IS LOWERED TO 45 KT.
PILAR IS MOVING QUICKLY WEST-SOUTHWESTWARD (255/19 KT), STEERED BY A
COMBINATION OF THE LOW-LEVEL NORTHEASTERLY GAP WIND FLOW AND THE
FLOW ASSOCIATED WITH A MID-LEVEL RIDGE TO THE NORTH AND NORTHWEST OF
THE STORM. A WEAKNESS IS EXPECTED TO DEVELOP IN THIS RIDGE DURING
THE NEXT COUPLE OF DAYS AS A MID-LEVEL TROUGH/CUT-OFF LOW MOVES
TOWARD THE BAJA CALIFORNIA PENINSULA. THIS WEAKNESS IN THE RIDGE
SHOULD CAUSE PILAR TO GRADUALLY SLOW DOWN AND TURN TOWARD THE WEST
AND WEST-NORTHWEST THROUGH EARLY NEXT WEEK. THE TRACK GUIDANCE IS IN
REASONABLY GOOD AGREEMENT ON THIS SCENARIO. THE LATEST NHC TRACK
FORECAST GENERALLY REMAINS BETWEEN THE HCCA AND TVCE CONSENSUS AIDS,
AND THIS PREDICTION IS VERY SIMILAR TO THE PREVIOUS ONE.
THE WESTERLY SHEAR AND BOUTS OF DRY AIR ENTRAINMENT ARE LIKELY TO
CONTINUE OVER THE NEXT COUPLE OF DAYS. THE LATEST GFS AND ECMWF
SIMULATED SATELLITE IMAGERY DOES SHOW CONVECTION RETURNING WITH
PILAR LATER THIS MORNING, BUT IT ALSO SUGGESTS THAT ITS CONVECTIVE
STRUCTURE MAY CONTINUE FLUCTUATING IN THE COMING DAYS. SINCE PILAR
IS A SMALL STORM, IT WILL BE MORE SUSCEPTIBLE TO DISRUPTIONS FROM
THE MARGINAL ENVIRONMENTAL CONDITIONS. ALTHOUGH PILAR WILL REMAIN
OVER VERY WARM WATERS, THE INTENSITY GUIDANCE GENERALLY SHOWS LITTLE
CHANGE IN STRENGTH THROUGH THE WEEKEND, AND THE NHC FORECAST FOLLOWS
SUIT. AS PILAR GAINS LATITUDE AT DAYS 3-5, THE CYCLONE IS EXPECTED
TO WEAKEN AS IT ENCOUNTERS STRONGER SOUTHWESTERLY SHEAR. IN FACT,
THIS FORECAST SHOWS PILAR DEGENERATING TO A 30-KT REMNANT LOW BY THE
END OF THE PERIOD.
FORECAST POSITIONS AND MAX WINDS
INIT 03/0900Z 10.4N 101.4W 45 KT 50 MPH
12H 03/1800Z 10.0N 103.7W 45 KT 50 MPH
24H 04/0600Z 9.7N 106.7W 45 KT 50 MPH
36H 04/1800Z 9.8N 109.5W 45 KT 50 MPH
48H 05/0600Z 10.1N 111.8W 45 KT 50 MPH
60H 05/1800Z 10.5N 113.8W 45 KT 50 MPH
72H 06/0600Z 11.3N 115.1W 40 KT 45 MPH
96H 07/0600Z 13.0N 117.5W 35 KT 40 MPH
120H 08/0600Z 14.5N 120.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
FORECASTER REINHART
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