Much weakened TC 11S(FREDDY) set to re-intensify forecast landfall near Quelimane/MOZ//Invest 97W//Invest 99P//0903utc

JTWC IS ISSUING 12HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TC 11S(FREDDY).

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: INTENSITIES ON EARLIER POSITIONS HAVE BEEN LOWERED SIGNIFICANTLY, THUS THE FORECAST INTENSITY HAS BEEN ADJUSTED 30 KNOTS LOWER. FORECAST DISCUSSION: TC FREDDY IS EXPECTED TO CONTINUE SLOWLY TRACKING NORTHWESTWARD ALONG THE NORTHEASTERN SIDE OF THE STEERING RIDGE THROUGH THE NEXT 48 HOURS. THE SYSTEM WILL MAINTAIN A TRACK SPEED OF ROUGHLY FIVE KNOTS THROUGH LANDFALL, AS THE NER TO THE NORTHEAST COMPETES FOR DOMINANCE IN THE STEERING FLOW. TC FREDDY IS EXPECTED TO MAKE LANDFALL ALONG THE COAST OF MOZAMBIQUE AROUND TAU 48 BEFORE MOVING SLOWLY INLAND AND DISSIPATING. IN THE NEAR-TERM, SOUTHERLY MID-LEVEL SHEAR AND CONTINUED DRY AIR INTRUSION WILL KEEP A LID ON INTENSIFICATION AND IT IS LIKELY TO EVEN WEAKEN A BIT MORE OVER THE FIRST 12 HOURS OF THE FORECAST. AFTER TAU 24 HOWEVER, CONDITIONS ARE EXPECTED TO IMPROVE, WITH THE ATMOSPHERE MOISTENING UP AND THE MID-LEVEL SHEAR DROPPING OFF TO MORE REASONABLE AND SUPPORTIVE LEVELS. AT THE SAME TIME THE SYSTEM WILL BEGIN MOVING OVER AN AREA OF ENHANCED OCEAN HEAT CONTENT (OHC) WHICH LIES JUST OFFSHORE OF MOZAMBIQUE. THE ONLY CAP ON INTENSIFICATION WILL BE THE RELATIVELY LIMITED OUTFLOW, WITH DEVELOPMENT OF A POLEWARD OR EQUATORWARD CHANNEL NOT EXPECTED. THE SYSTEM IS EXPECTED TO REACH PEAK INTENSITY OF 75 KNOTS IMMEDIATELY PRIOR TO LANDFALL. ONCE ASHORE, THE SYSTEM WILL RAPIDLY WEAKEN AND DISSIPATION BELOW WARNING CRITERIA IS EXPECTED BY TAU 96.

MODEL DISCUSSION: WITH THE EXCEPTION OF THE GFS DETERMINISTIC TRACKER WHICH WILL BE DISCUSSED IN THE ALTERNATE SCENARIO BELOW, TRACK GUIDANCE IS IN GOOD AGREEMENT ON NORTHWESTWARD TRACK, THOUGH THERE ARE SIGNIFICANT ALONG-TRACK DIFFERENCES BETWEEN THE CONSENSUS MEMBERS. THE ALONG-TRACK SPREAD BEGINS TO EMERGE AS EARLY AS TAU 24, WITH THE EUROPEAN MODELS (ECMWF, ECENS, UKMET) FAR OUTRACING THE AMERICAN MODELS (GFS, GEFS, HWRF, NVGM), AND THIS TREND CONTINUES AND GROWS LARGER THROUGH THE FORECAST PERIOD. SO WHILE CONFIDENCE IN THE DIRECTION OF MOVEMENT IS HIGH, THE ENHANCED ALONG-TRACK SPREAD LEADS TO LOW CONFIDENCE IN THE OVERALL TRACK FORECAST. INTENSITY GUIDANCE IS MIXED, WITH ALL MODELS SHOWING A TREND LINE THAT BASICALLY CONFORMS WITH THE JTWC FORECAST, WITH THE NOTABLE EXCEPTION OF BOTH VERSIONS OF COAMPS-TC, WHICH SHOW SIGNIFICANTLY MORE INTENSIFICATION, TO A PEAK OF 100 KNOTS, BY TAU 48. THE JTWC FORECAST LIES ABOUT FIVE KNOTS ABOVE THE CONSENSUS MEAN THROUGH LANDFALL, THEN SLIGHTLY BELOW THE MEAN THEREAFTER WITH MEDIUM CONFIDENCE. AS MENTIONED ABOVE THE GFS AND TO A LESSER EXTENT THE GEFS ENSEMBLE, CONTINUE TO SHOW AN ALTERNATE TRACK SCENARIO FOR TC 11S, WHICH AFTER MAKING A RUN TOWARDS THE COAST, TOUCHING A TOE ON LAND AROUND TAU 72, THEN MAKES A U-TURN, AND MOVING BACK OUT TO SEA BY TAU 120. ANALYSIS OF THE UPPER-LEVEL STEERING PATTERN REVEALS THAT THE GFS BREAKS DOWN THE STR TO THE SOUTHWEST WHILE BUILDING THE NER TO THE NORTHEAST AS THE SYSTEM MAKES LANDFALL AND THUS THE STEERING PATTERN SHIFTS TO THE NER. THIS IS DIRECTLY OPPOSITE OF THE ECMWF SOLUTION. THE GFS HAS BEEN SHOWING VARIATIONS OF THIS THEME FOR SEVERAL RUNS AND THUS CANNOT BE FULLY DISCOUNTED EVEN THOUGH IT IS SO FAR, THE ONLY MODEL THAT SHOWS THIS SOLUTION.

SAR DATA INDICATED WINDS UP TO 94 KNOTS HOWEVER THESE WERE DEPICTED WITHIN AN AREA OF CONVERGENT FLOW THAT WAS ASSESSED AS NOT REPRESENTATIVE OF THE OVERALL INTENSITY.

Last Updated - 03/07/23 Valid - 03/15/23 - 03/28/23 The Madden-Julian Oscillation (MJO) strengthened during the first week of March as a more coherent pattern of anomalous upper-level divergence (convergence) developed over the East Pacific (Indian Ocean). The amplitude of the RMM-based index increased since the beginning of the month and dynamical models maintain a strong MJO with eastward propagation over the Western Hemisphere during the next two weeks. By week-3, the MJO is forecast to be centered across Africa and the western Indian Ocean. The magnitude of the 200-hPa velocity anomalies are forecast to be very large through week-2, which raises forecast confidence that the MJO influences global tropical rainfall and modulates tropical cyclone development. In addition, the MJO is likely to enhance subtropical moisture feeding into the west coast of the United States through mid-March. Tropical cyclone (TC) Kevin developed across the South Pacific on March 1 and then intensified to maximum sustained winds of 135 knots on March 4. Kevin made landfall on Vanuatu only a few days after TC Judy crossed the South Pacific island. Long-lived TC Freddy has tracked west across the entire basin during early to mid-February, made its first landfall at Mananjary, Madagascar on February 21, and a second landfall near Vilankulos, Mozambique on February 24. According to the Joint Typhoon Warning Center, Freddy is forecast to make another landfall in central Mozambique on March 10 or 11. Recent model solutions have Freddy reemerging across the Mozambique Channel late in week-1 or by early in week-2. No TC development area is posted for the Mozambique Channel since this would be the remnant low associated with Freddy. Depending on the future track of Freddy, a risk for heavy rainfall, flooding, and high winds may continue for Mozambique and Madagascar from March 15 to 21. However, due to large forecast uncertainty on the fate of Freddy by this time period, a 50 percent chance of above-average rainfall is not posted for these areas. A moderate (40 percent) chance of TC formation is posted for the Coral Sea and South Pacific from March 15 to 21. This favored area for genesis is supported by MJO composites and the deterministic model runs. It should be noted that within the slight (20 percent) chance region, multiple TCs may form prior to the start of week-2, March 15. The large-scale environment is likely to be unfavorable for additional TC development over the South Indian Ocean through week-2, March 15-21. The precipitation outlook for weeks 2 and 3 are based on a historical skill weighted blend of the GEFS, CFS, ECCC, and ECMWF models, MJO precipitation composites for phases 8, 1, 2, and 3, and considerations of the ongoing La Nina background state. The MJO strongly supports above-average rainfall across eastern Brazil during week-2, while below-average rainfall is favored for the western Maritime Continent. From March 15 to 21, increased chances (above 50 percent, or higher) for above-average rainfall are posted from Hawaii eastward to the western United States. During weeks 2 and 3, favored above-average rainfall is forecast across parts of the Horn of Africa and western Indian Ocean.