467
WTPZ44 KNHC 040836
TCDEP4
TROPICAL STORM PILAR DISCUSSION NUMBER 27
NWS NATIONAL HURRICANE CENTER MIAMI FL EP192023
300 AM MDT SAT NOV 04 2023
DEEP CONVECTION HAS CONTINUED TO PULSE NEAR AND TO THE EAST OF THE
CENTER OF PILAR OVERNIGHT. THERE WERE NO COMPLETE ASCAT PASSES OVER
THE STORM TONIGHT, BUT A PARTIAL ASCAT-C PASS SUGGESTS THE STRONGEST
WINDS REMAIN CONFINED TO THE NORTHERN SEMICIRCLE. THE VARIOUS
SATELLITE INTENSITY ESTIMATES RANGE FROM 30-44 KT, AND THE INITIAL
INTENSITY IS HELD AT 40 KT FOR THIS ADVISORY.
DESPITE MOVING OVER WARM WATERS IN A WEAK TO MODERATE WESTERLY SHEAR
ENVIRONMENT, THE SMALL STORM HAS STRUGGLED TO SUSTAIN CONVECTION AT
TIMES DURING THE PAST COUPLE OF DAYS DUE TO THE NEGATIVE EFFECTS OF
DRY AIR. IN THE NEAR TERM, GFS AND ECMWF SIMULATED SATELLITE IMAGERY
SUGGEST THIS TREND COULD CONTINUE. THE UPPER-LEVEL ENVIRONMENT IS
FORECAST TO BECOME MORE DIFFLUENT IN 24-36 H, AND THE GFS ALONG WITH
SOME OF THE REGIONAL MODELS SHOW STRENGTHENING COULD OCCUR DURING
THIS PERIOD. HOWEVER, THERE ARE ALSO INDICATIONS THAT MID-LEVEL
SHEAR WILL INCREASE AROUND THE SAME TIME, WHICH WOULD LIKELY RESULT
IN ADDITIONAL BOUTS OF DRY AIR INTRUSIONS. WHILE SMALL INTENSITY
FLUCTUATIONS SEEM POSSIBLE DURING THE NEXT COUPLE OF DAYS, THE NHC
FORECAST FOLLOWS THE CORRECTED CONSENSUS (HCCA) AID AND SHOWS NO
CHANGE IN STRENGTH THROUGH THE WEEKEND. WEAKENING IS EXPECTED
BEGINNING MONDAY AS PILAR MOVES INTO A DRIER AND STRONGLY SHEARED
ENVIRONMENT. SIMILAR TO THE PREVIOUS PREDICTION, THIS FORECAST SHOWS
DEGENERATION INTO A REMNANT LOW BY 72 H AND DISSIPATION BY DAY 5.
A MID-LEVEL RIDGE TO THE NORTH OF PILAR IS STEERING THE STORM
QUICKLY WESTWARD (265 DEGREES/14 KT). THIS STEERING RIDGE IS
FORECAST TO BECOME ERODED BY A MID-LEVEL TROUGH NEAR THE BAJA
CALIFORNIA PENINSULA OVER THE WEEKEND. THIS SHOULD CAUSE PILAR TO
GRADUALLY SLOW DOWN AND GAIN SOME LATITUDE, WITH A TURN TOWARD THE
WEST-NORTHWEST AND NORTHWEST FORECAST EARLY NEXT WEEK. THERE IS
LARGE SPREAD IN THE TRACK GUIDANCE ENVELOPE BEYOND 24 H, WITH THE
DIFFERENCES LIKELY RELATED TO THE STRENGTH AND VERTICAL DEPTH OF THE
CYCLONE. THE UPDATED NHC TRACK FORECAST IS SIMILAR TO THE PREVIOUS
ONE AND REMAINS CLOSE TO HCCA, WHICH FALLS BETWEEN THE STRONGER
(WEAKER) MODELS ON THE RIGHT (LEFT) SIDE OF THE GUIDANCE ENVELOPE.
FORECAST POSITIONS AND MAX WINDS
INIT 04/0900Z 9.8N 107.3W 40 KT 45 MPH
12H 04/1800Z 9.8N 109.4W 40 KT 45 MPH
24H 05/0600Z 10.1N 111.7W 40 KT 45 MPH
36H 05/1800Z 10.6N 113.6W 40 KT 45 MPH
48H 06/0600Z 11.3N 115.3W 40 KT 45 MPH
60H 06/1800Z 11.9N 116.4W 35 KT 40 MPH
72H 07/0600Z 12.7N 117.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 08/0600Z 14.5N 119.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 09/0600Z...DISSIPATED
FORECASTER REINHART
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