892
WTPZ42 KNHC 230841
TCDEP2
TROPICAL DEPRESSION NORMA DISCUSSION NUMBER 23
NWS NATIONAL HURRICANE CENTER MIAMI FL EP172023
300 AM MDT MON OCT 23 2023
NORMA HAS WEAKENED TO A TROPICAL DEPRESSION AS THE CYCLONE HAS BEEN
VOID OF DEEP CONVECTION SINCE YESTERDAY AFTERNOON. A COUPLE OF ASCAT
OVERPASS BETWEEN 0354 AND 0441 UTC SHOWED PEAK WINDS IN THE 31 TO 33
KT RANGE, AND ASSUMING ADDITIONAL WEAKENING HAS OCCURRED SINCE THAT
TIME, THE INITIAL INTENSITY HAS BEEN LOWERED TO 30 KT. DRY MID-LEVEL
AIR HAS BEEN ENTRAINED INTO THE CIRCULATION FROM THE NORTHWEST, AND
GIVEN THE CURRENT STRONG SHEAR OVER THE SYSTEM, IT APPEARS UNLIKELY
THAT SIGNIFICANT DEEP CONVECTION WILL RETURN. NORMA SHOULD MOVE
ONSHORE THE COAST OF WESTERN MAINLAND MEXICO LATER THIS MORNING, AND
IT IS EXPECTED TO RAPIDLY WEAKEN AND EITHER BECOME POST-TROPICAL OR
DISSIPATE TODAY OVER THE HIGH TERRAIN OF WESTERN MEXICO.
NORMA TOOK A SOUTHEASTWARD JOG OVERNIGHT, BUT IT APPEARS TO HAVE
RESUMED AN EASTWARD MOTION AT ABOUT 6 KT. A GENERAL EASTWARD TO
MOTION IS EXPECTED TO CONTINUE UNTIL DISSIPATION OCCURS. THE MORE
SOUTHWARD INITIAL POSITION REQUIRED A SOUTHWARD ADJUSTMENT OF THE
TRACK FORECAST, BUT IT OTHERWISE REMAINS NEAR THE CENTER OF THE
GUIDANCE ENVELOPE.
HEAVY RAINFALL ASSOCIATED FLOODING REMAINS THE PRIMARY THREAT WITH
THIS SYSTEM.
KEY MESSAGES:
1. HEAVY RAINFALL ASSOCIATED WITH NORMA WILL DIMINISH ACROSS
PORTIONS OF WESTERN MEXICO TODAY. ADDITIONAL ISOLATED HEAVY
RAINFALL MAY PRODUCE ISOLATED FLASH FLOODING AND MUDSLIDES IN AREAS
OF HIGHER TERRAIN.
2. GUSTY WINDS ARE POSSIBLE ALONG THE COAST OF SINALOA MEXICO THIS
MORNING.
FORECAST POSITIONS AND MAX WINDS
INIT 23/0900Z 24.5N 108.4W 30 KT 35 MPH
12H 23/1800Z 24.7N 107.3W 25 KT 30 MPH...POST-TROP/INLAND
24H 24/0600Z...DISSIPATED
FORECASTER BROWN
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