| Current Conditions | ||
| Temp |  | 0.2 C |
| RH | | 5 % |
| Wind | | W 11 mph |
| Road | | Open (4x4) |
|
Menu of Text Products for the Hawaiian Islands and the Tropical Pacific/Atlantic Oceans: |
|
Narrow the Menu List Select Time Limit: 12 hours | 24 hours | 48 hours | 72 hours | No time limit Select Product Type: All | Routine Bulletins/FCSTS | Warnings/Watches/Advisories | HAWN Weather | Tropical | Marine | Aviation | Daily Obs | Special |
|
|
Hawaiian Islands Synoptic Discussion and Guidance 178 FXHW60 PHFO 250654 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 854 PM HST Mon Feb 24 2020 .SYNOPSIS... A mostly dry and pleasant trade wind pattern is expected through midweek. Clouds and showers will favor windward areas, especially through the overnight and early morning periods each day. Rainfall chances are expected to trend up Thursday through the weekend as an upper disturbance moves over the area. This combined with increasing trades will translate to a wet and windy pattern this weekend, which may continue through early next week. && .DISCUSSION... The latest surface analysis showed high pressure building north of the area behind a dissipating frontal boundary stalled to the north. A return of moderate trade winds has been the result today across the state. The leading edge of a band of moisture near the stalled boundary combined with the trades are supporting scattered, mostly light, showers over the adjacent windward waters of the smaller islands this evening. Expect this general trend to hold overnight into Tuesday morning with clouds and showers favoring windward areas. The short-term guidance remains in decent agreement and depicts a mostly dry and stable trade wind pattern continuing through midweek as high pressure builds to the north and upper heights rise. Trades will steadily increase and become breezy, especially by Wednesday. Clouds and showers will favor windward areas, especially through the overnight and early morning periods. Rainfall accumulations should remain light with precipitable water (PW) values forecast to remain around or below an inch (dry). The extended guidance shows a pattern shift later in the week through the upcoming weekend as an upper low closes off across the state and 1040 mb high pressure sets up to the north. Increasing instability associated with lowering upper heights combined with a modest increase in moisture being drawn into the area will support increasing rainfall chances. As the pressure gradient tightens in response to the 1040 mb high, local winds will strengthen and become windy. Guidance suggests this wet and windy pattern holding into next week, which may result in localized flooding concerns where the heaviest rainfall becomes focused. Although most of the showers will focus over windward areas, some will spread into leeward sections given the strong winds expected. && .AVIATION... Tonight a 1031 mb high to the north of the island chain will allow for moderate east northeast trade flow to persist. Thus, isolated to scattered showers will press up against the windward coasts and slopes. Periods of MVFR conditions may develop due to lower ceilings from the passing shower activity. Otherwise, mainly dry weather and VFR for leeward locations. No AIRMETs are in effect at this time. && .MARINE... High pressure will strengthen far northeast of the islands over the next couple days, resulting in increasing trade winds across the island chain. This in combination with an incoming large long- period northwest swell will bring Small Craft Advisory (SCA) conditions to most marine zones by late Tuesday or Tuesday night. SCA conditions will continue through the weekend and into early next week for most areas. In fact, the trades will become even stronger late in the week and over the weekend as a new and 1040+ mb high builds north of the state, with near-Gale to Gale force winds likely to develop across much of the marine area. The current small short period northwest swell will linger through tonight. A larger long-period northwest swell will fill in Tuesday morning, peak late Tuesday and Tuesday night, then gradually lower Wednesday and Wednesday night. Current guidance continues to show surf reaching high end advisory levels with this swell, but if the swell comes in a bit higher than expected, the advisory may need to be upgraded to a warning. We will continue to closely monitor the NOAA buoys northwest of the state through the night as the swell begins to arrive. Another long period, but slightly smaller northwest swell is expected to build Wednesday night and Thursday, peak Thursday night, then lower gradually Friday through Sunday. Advisory level surf is expected with this swell. Short period choppy surf along east facing shores will gradually rise through the week and become rather large by the weekend due to strengthening trade winds. Advisory level surf is likely by the weekend, with warning level surf possible Sunday through early next week. There will also be a series of small background south swells through the week and on through the weekend. && .HFO WATCHES/WARNINGS/ADVISORIES... High Surf Advisory from noon Tuesday to 6 AM HST Wednesday for Waianae Coast-Oahu North Shore-Oahu Koolau-Molokai-Maui Windward West-Maui Central Valley-Windward Haleakala. High Surf Advisory from 6 AM Tuesday to 6 AM HST Wednesday for Niihau-Kauai Windward-Kauai Leeward. Small Craft Advisory until 6 PM HST Wednesday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. Small Craft Advisory from 6 AM Tuesday to 6 PM HST Wednesday for Kauai Northwest Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-Oahu Windward Waters-Oahu Leeward Waters- Kaiwi Channel-Maui County Windward Waters. && $$ DISCUSSION...Gibbs AVIATION...Thomas MARINE...Jelsema Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office |
|