909
WTPZ44 KNHC 050838
TCDEP4
TROPICAL STORM PILAR DISCUSSION NUMBER 31
NWS NATIONAL HURRICANE CENTER MIAMI FL EP192023
200 AM MST SUN NOV 05 2023
PILAR HASN'T CHANGED MUCH IN IN ORGANIZATION OVER THE PAST SEVERAL
HOURS. THE STORM CONTINUES TO HAVE SOME CONVECTIVE BANDING
FEATURES ALONG WITH A SOMEWHAT RAGGED-LOOKING CENTRAL DENSE
OVERCAST. CLOUD TOPS CONTINUE TO BE QUITE COLD, AT -70 DEG C OR
COLDER, AND THE UPPER-LEVEL OUTFLOW PATTERN ALSO REMAINS FAIRLY
WELL DEFINED. THE CURRENT INTENSITY ESTIMATE IS HELD AT 45 KT IN
AGREEMENT WITH SUBJECTIVE DVORAK VALUES FROM TAFB AND SAB, AS WELL
AS OBJECTIVE AI-ADT ESTIMATES FROM UW-CIMSS. ASCAT SCATTEROMETER
DATA FROM A FEW HOURS AGO SUGGEST THAT THIS ESTIMATE MAY BE A BIT
GENEROUS, SINCE THAT INSTRUMENT SHOWED SOMEWHAT LOWER WIND SPEEDS.
HOWEVER IT IS ASSUMED THAT THERE WAS SOME UNDERSAMPLING BY ASCAT OF
THE MAXIMUM WINDS IN THIS SMALL TROPICAL CYCLONE.
VERTICAL WIND SHEAR OVER THE CYCLONE IS EXPECTED TO REMAIN FAIRLY
LOW TODAY, AND THIS ALONG WITH A WARM OCEAN COULD ALLOW FOR A
LITTLE MORE SHORT-TERM STRENGTHENING. IN 24 HOURS AND BEYOND,
HOWEVER, THE DYNAMICAL GUIDANCE SHOWS A SUBSTANTIAL INCREASE IN
SHEAR AS PILAR BEGINS TO ENCOUNTER STRONG SOUTHWESTERLY FLOW
ASSOCIATED WITH A BROAD UPPER-LEVEL TROUGH TO ITS NORTHWEST. THIS
INCREASED SHEAR SHOULD CAUSE WEAKENING, AND THE SYSTEM IS
LIKELY TO BE REDUCED TO A REMNANT LOW PRESSURE AREA IN 2 TO 3
DAYS, OR POSSIBLY SOONER. THE OFFICIAL INTENSITY FORECAST IS
SIMILAR TO THE PREVIOUS ONE AND IS ALSO CLOSE TO THE MODEL
CONSENSUS.
A WESTWARD MOTION CONTINUES FOR NOW, AT A SLOWER FORWARD SPEED OF
AROUND 10 KT. OVER THE NEXT DAY OR SO, THE MID-LEVEL RIDGE TO THE
NORTH OF PILAR IS FORECAST TO WEAKEN DUE TO THE INFLUENCE OF A LOW
JUST TO THE WEST OF THE BAJA CALIFORNIA PENINSULA. AS A RESULT,
THE SYSTEM IS LIKELY TO TURN WEST-NORTHWESTWARD TO NORTHWESTWARD
DURING THE NEXT 24 HOURS OR SO. THE OFFICIAL FORECAST TRACK IS
SOMEWHAT TO THE RIGHT OF THE PREVIOUS NHC PREDICTION, BUT IS STILL
NEAR THE SOUTHERN SIDE OF THE GUIDANCE SUITE. THIS IS FAIRLY CLOSE
TO THE LATEST SIMPLE AND CORRECTED DYNAMICAL MODEL CONSENSUS
TRACKS.
FORECAST POSITIONS AND MAX WINDS
INIT 05/0900Z 10.6N 112.1W 45 KT 50 MPH
12H 05/1800Z 11.0N 113.2W 50 KT 60 MPH
24H 06/0600Z 11.6N 114.2W 45 KT 50 MPH
36H 06/1800Z 12.5N 115.1W 40 KT 45 MPH
48H 07/0600Z 13.8N 116.3W 30 KT 35 MPH
60H 07/1800Z 15.2N 117.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 08/0600Z 16.5N 118.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 09/0600Z...DISSIPATED
FORECASTER PASCH
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