Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 217 AM EDT Mon Jul 20 2020 Valid 00Z Tue Jul 21 2020 - 00Z Tue Jul 28 2020 A broad upper-level ridge is forecast to persist across the Central Pacific through the week. Breezy trades are expected to weaken somewhat by Tuesday, before strengthening again later in the week. A broad weakness in the ridge is forecast to cross the state from east to west Tuesday through Friday. The GEFS continues to show 500 hPa height anomalies of -1 to -2 standard deviations as this feature moves across the state, which should enhance instability somewhat. An area of low pressure currently near 15N/120W is being monitored by the National Hurricane Center for possible tropical development over the next several days as it moves generally westward. By Sunday-Monday, models/ensemble members show some consensus that this system could approach Hawaii from the east. Solutions differ widely on the intensity by that time, with the deterministic ECMWF among the stronger solutions and the GFS on the weak side, but there is some consensus on the timing/track among ensemble guidance at this point. Through much of the week models showed sufficient consensus that a general model blend is preferred. By next weekend, given the described potential for a tropical system, something closer to ensemble means is favored at this time, which would indicate an increased potential for showers and possibly heavy rains by Sun-Mon, but any further impacts are uncertain at this point, pending any possible/eventual tropical development. Ryan