| Current Conditions | ||
| Temp |  | 9.1 C |
| RH | | 15 % |
| Wind | | NE 14 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 996 FXHW60 PHFO 232000 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 1000 AM HST Sat Jun 23 2018 .SYNOPSIS... High pressure north and northeast of the islands will support breezy trade winds for the next week. The trades will deliver passing clouds and showers that will primarily affect windward slopes and coasts, with a few brief showers spreading to leeward areas of the smaller islands. Leeward slopes of the Big Island will see afternoon and evening clouds that will drop a few showers before generally clearing at night. && .DISCUSSION... A 1034 mb surface high far N of the islands will move steadily E through Tuesday while maintaining a central pressure in the 1030's. The high is then expected to wobble around to the distant NE of the islands through the end of next week. The associated pressure gradient will ensure seasonable breezy trade winds remain over the islands for the foreseeable future, with some subtle fluctuations. Water vapor imagery and model analyses indicate a mid- to upper- level low centered about 500 miles NE of the Big Island. Upper air soundings and latest visible satellite images indicate that this feature is not significantly destabilizing the lower atmosphere, but an increase in showery low clouds is noted just a little E of the islands, and extending E of 150W. In the short term, there is a bit of a break in the low cloud field immediately upstream of the islands from Oahu to the Big Island, with showery low clouds in greater concentration near and E of Kauai. This should keep Kauai somewhat showery today while the other islands see fewer showers. Model guidance appears to have initialized well, and depicts the mid- level low gradually weakening as it drifts W over the next 24 to 48 hours, while the upper-level low moves N. This is expected to lead to an increase in trade wind showers later tonight and on Sunday, and potentially again around Monday night, as the mid-level low weakens to a trough and moves over the islands. Most of the associated moisture will focus over windward slopes and coasts, but the locally strong trade winds will push a few showers to leeward areas on the smaller islands. Leeward slopes of the Big Island will see the typical afternoon and evening clouds and showers that tend to gradually clear overnight. While the trade winds will keep the Big Island's volcanic emissions away from the smaller islands, they will continue to stream over portions of the Puna and Kau districts. Additionally, eddies that develop to the lee of the Big Island will occasionally lead to vog moving ashore over the Kona and Kohala districts. && .AVIATION... Breezy, occasionally strong, trade winds will persist through the day as a ridge of high pressure remains north of the state. VFR will predominate, with passing showers bringing brief MVFR conditions to windward and mauka sections of the islands. AIRMET Tango remains in effect for low level turbulence over and SW of all islands. && .MARINE... Trades are forecast to steadily increase through the weekend and hold in the fresh to strong category as high pressure builds north of the state. A Small Craft Advisory remains in effect for most waters east of Oahu through Sunday due to the breezy winds. Although the trades may slightly back off briefly by Monday, locally strong trades will remain likely over the typical channels around Maui County and south of the Big Island. Surf along east facing shores will become rough through the weekend as the trades increase locally and upstream across the eastern Pacific. After the trades briefly weaken around Monday, a surge upstream and locally will likely translate to increasing surf that may near the advisory level by midweek. Surf along south facing shores is expected to trend back up next week as overlapping long-period south swells fill in due to recent activity across the southern Pacific. The first swell is currently building at the American Samoa buoy within the 14-16 second bands this morning, which should continue through the weekend as the second source fills in. The latest WAVEWATCH III guidance depicts this source peaking Monday at the Samoa buoy at 7 ft 15 seconds. Locally, surf will begin to build along south facing shores from the first source Tuesday, then become reinforced by Thursday as the second/larger source fills in. Surf may reach the south shore advisory level at the peak of this reinforcement by Thursday. Looking ahead into the first week of July, the active trend could persist along south facing shores. The latest ECMWF and GFS guidance supports a gale-force low passing just south of the Tasman Sea and New Zealand today through Monday with gales setting up within Hawaii's swell window. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 PM HST Sunday for Oahu Leeward Waters- Kaiwi Channel-Maui County Windward Waters-Maui County Leeward Waters- Maalaea Bay-Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ SYNOPSIS/DISCUSSION...Birchard AVIATION...TS MARINE...Foster Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office |
|