FXHW60 PHFO 191330 AFDHFO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HONOLULU HI 330 AM HST TUE NOV 19 2013 .SYNOPSIS... QUIET AND MOSTLY DRY WEATHER WILL PERSIST THROUGH TOMORROW MORNING...WITH SHOWERS INCREASING LATE TOMORROW INTO FRIDAY AS A FRONT APPROACHES...AND MOVES DOWN THE ISLAND CHAIN. LIGHT WINDS WILL BE FROM THE SOUTH AND SOUTHWEST...UNTIL THE FRONTAL PASSAGE SWITCHES WINDS TO THE NORTH. TRADE WINDS WILL RETURN NEXT WEEKEND AS THE FRONT STALLS AND WEAKENS NEAR THE BIG ISLAND. HIGH CLOUDS ARE EXPECTED TO INCREASE LATER TODAY AND WEDNESDAY...AND THEN DIMINISH AGAIN ON THURSDAY. && .DISCUSSION... CURRENTLY...SKIES OVER THE ISLANDS ARE MOSTLY CLEAR...AND DRY CONDITIONS PREVAIL IN MOST AREAS...EXCEPT FOR PERSISTENT SHOWERS THAT HAVE BEEN ANCHORED ALONG THE LOWER SLOPES OF WINDWARD HALEAKALA FOR THE PAST SEVERAL HOURS. LOW CLOUDS ARE INCREASING IN COVERAGE OVER WATERS S OF THE ISLANDS FROM KAUAI TO MOLOKAI...BUT RADAR IS THUS FAR NOT DETECTING ANY SHOWERS FALLING FROM THESE STABLE CLOUDS. A RECENTLY RECEIVED VIIRS NIGHTTIME VISIBLE IMAGE CONFIRMS THAT THESE ARE STABLE STRATOCUMULUS. LOOKS LIKE A SUNNY START TO THE DAY NEARLY STATEWIDE...WITH INCREASING CLOUDS OVER INTERIOR AND LEEWARD AREAS THIS AFTERNOON. SOUNDINGS CONTINUE TO INDICATE A STRONG SUBSIDENCE INVERSION BASED BETWEEN 5.5 AND 7 KFT...THEREBY KEEPING A STRONG LID ON ANY CONVECTION TODAY. THE LOW LEVEL FLOW OVER THE ISLANDS WILL CONTINUE TO FAVOR A S TO SE DIRECTION THROUGH EARLY TOMORROW...AS A SURFACE RIDGE EXTENDS OVER THE ISLANDS FROM THE E...AND A PERSISTENT FRONT LINGERS NW OF KAUAI. BLOCKING OF THIS FLOW BY THE BIG ISLAND WILL ALLOW LAND AND SEA BREEZES TO DOMINATE ISLAND WEATHER. LAND BREEZES WILL CLEAR SKIES OVER THE ISLANDS AT NIGHT...WITH LOW CLOUDS INCREASING ACROSS ISLAND INTERIORS DURING THE DAY DUE TO THE CONVERGING SEA BREEZES. THE PREVAILING WINDS WILL ALSO BE CONDUCIVE FOR VOG EMANATING FROM SE BIG ISLAND TO SPREAD OVER THE REMAINDER OF THE STATE. A RIDGE ALOFT E OF THE ISLANDS WILL MAINTAIN A STABLE ATMOSPHERE IN THE SHORT TERM...BUT IS IN THE PROCESS OF SHIFTING EASTWARD. A TROUGH ALOFT NW OF THE ISLANDS WILL CONTINUE TO FORCE THE STABILIZING RIDGE ALOFT EASTWARD THROUGH THURSDAY...AND HELP TO PUSH THE LURKING FRONTAL BOUNDARY EASTWARD. INSTABILITY WILL INCREASE ALONG THE WESTERN END OF THE ISLAND CHAIN...WITH MOISTURE POOLED W OF THE ISLANDS ALSO ADVECTING EASTWARD. THE EXPECTATION IS THAT PRE-FRONTAL SHOWERS AND S TO SW WINDS WILL INCREASE NEAR KAUAI OAHU AND PORTIONS OF MAUI COUNTY LATE WEDNESDAY...PERSISTING THROUGH THURSDAY. A WEAK FRONT IS EXPECTED TO MOVE DOWN THE CHAIN ON FRIDAY...WITH WINDS BRIEFLY SWITCHING TO THE N AS THE FRONT PASSES. THE FRONT IS EXPECTED TO MOVE OVER THE ISLANDS IN AN INCREASINGLY STABLE ENVIRONMENT...AND IS NOT EXPECTED TO BE A SIGNIFICANT RAIN PRODUCER. HOWEVER...SHALLOW MOISTURE ASSOCIATED WITH THE REMNANTS OF THE FRONT MAY PILE UP ALONG WINDWARD AREAS OF THE BIG ISLAND AND MAUI AS WINDS VEER TO THE NE THIS WEEKEND. AT THE SAME TIME MOISTURE SURGES IN THE PRE-FRONTAL SW FLOW AHEAD OF THE FRONT...FORECAST MODELS SHOW INCREASINGLY COLD TEMPERATURES IN THE MID AND UPPER LEVELS ASSOCIATED WITH THE SHARPENING TROUGH ALOFT...WHICH COULD SUPPORT THUNDERSTORM DEVELOPMENT. STILL LOOKING LIKE THE MOST LIKELY AREA/TIME IS KAUAI AND OAHU AND ADJACENT WATERS TOMORROW NIGHT AND THURSDAY. THE APPROACH AND PASSAGE OF THE UPPER TROUGH WILL ALSO LEAD TO INCREASING MID AND HIGH LEVEL CLOUDS FROM W TO E BEGINNING LATE TODAY...CLEARING THE ISLANDS TO THE E ON THURSDAY. && .AVIATION... NO AIRMETS ARE IN EFFECT. VFR CONDITIONS WILL PREVAIL...WITH ISOL MVFR CIG EXPECTED. && .MARINE... UNSEASONABLY SMALL SURF IS EXPECTED UNTIL THE WEEKEND. WINDS WILL BE LIGHT TO LOCALLY MODERATE...AND NO MARINE ADVISORIES ARE EXPECTED BEFORE THE WEEKEND. POST-FRONTAL NE WINDS MAY REACH SMALL CRAFT ADVISORY THRESHOLDS OVER THE WEEKEND WHERE THEY ARE MOST ACCELERATED AROUND MAUI AND THE BIG ISLAND. FORECAST MODELS CONTINUE TO INDICATE A GALE LOW DEVELOPING FAR NW OF THE ISLANDS THE NEXT COUPLE OF DAYS...WITH A CORRESPONDING MODERATE NNW SWELL BUILDING ON SATURDAY...BUT REMAINING BELOW ADVISORY LEVELS. THE OAHU SURF DISCUSSION /SRDHFO/ WAS UPDATED YESTERDAY... AND CONTAINS DETAILS ON THE SURF THAT CAN BE LOOSELY APPLIED STATEWIDE. THE PERSISTENT BOUNDARY LINGERING NW OF THE ISLANDS WILL PROVIDE THE FUEL FOR PERIODS OF THUNDERSTORMS OVER THE NW OFFSHORE WATERS THE NEXT COUPLE OF DAYS AS UPPER LEVEL IMPULSES TRACK FROM SW TO NE. && .HFO WATCHES/WARNINGS/ADVISORIES... NONE. && $$ BIRCHARD  FXHW60 PHFO 141416 AFDHFO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HONOLULU HI 400 AM HST WED MAY 14 2014 .SYNOPSIS... LINGERING MOISTURE ACROSS THE STATE WILL PROVIDE LOW CLOUDS WITH SOME SHOWERS TO THE ISLANDS TODAY. MUCH OF THE CLOUDS AND SHOWERS WILL FAVOR WINDWARD AND MAUKA AREAS. DRIER WEATHER WITH LIGHTER WINDS WILL RETURN TO THE ISLANDS THURSDAY THROUGH THE WEEKEND ...AS A SURFACE HIGH PRESSURE RIDGE MOVES NEAR THE STATE AHEAD OF AN APPROACHING FRONT FROM THE NORTHWEST OVER THE WEEKEND. && .DISCUSSION... MUCH OF THE LOW CLOUDS AND SHOWERS ARE AFFECTING MOLOKAI...MAUI AND THE BIG ISLAND EARLY THIS MORNING. DRIER CONDITIONS PREVAIL OVER REST OF THE ISLANDS...THOUGH SOME LOW CLOUDS ARE LINGERING OVER WINDWARD AND MOUNTAIN SECTIONS. THE CLOUD BAND THAT PERSISTED IN THE ISLAND VICINITY HAS THICKENED A BIT OVERNIGHT...AS REVEALED BY SATELLITE IMAGERY. EARLY MORNING SOUNDINGS FROM LIHUE AND HILO PRETTY MUCH MIRRORED THE DESCRIBED WEATHER CONDITIONS...WITH RATHER DRY AND STABLE AIR MASS OVER LIHUE WHILE HILO SOUNDING REVEALED DEEPER LOW LEVEL MOISTURE EXTENDING TO OVER 9 THOUSAND IN A STABLE AIR MASS. THIS BAND OF LOW CLOUDS IS EXPECTED TO LINGER IN THE ISLAND VICINITY TODAY. THEREFORE EXPECT CLOUDIER AND WETTER WEATHER FOR MOLOKAI...MAUI AND WINDWARD BIG ISLAND WHILE REST OF THE AREA WILL SEE MAINLY FAIR WEATHER. SURFACE HIGH PRESSURE NORTHWEST OF THE STATE COMBINING WITH A WEAK LOW PRESSURE SYSTEM NORTHEAST OF THE STATE CONTINUES TO BRING NORTHEAST TRADE WINDS TO THE ISLANDS TODAY. WINDS ARE EXPECTED TO VEER MORE EASTERLY BEGINNING TONIGHT AS A WEAK SURFACE RIDGE SLOWLY BUILDS NORTH OF THE STATE IN THE NEXT FEW DAYS. THIS WEAK SURFACE RIDGE WILL BRING LIGHTER EASTERLY TRADE WINDS TO THE ISLANDS THURSDAY INTO THE WEEKEND. IN FACT...THERE MAY BE ENOUGH SOUTHERLY COMPONENT IN THE WINDS RESULTING IN THE PERSISTENT CLOUD BAND SLOWLY LIFTING NORTH AND WEST...AWAY FROM THE ISLANDS BY FRIDAY. THEREFORE EXPECT DRIER WEATHER TO RETURN TO THE ISLANDS TOWARDS THE WEEKEND. THE WINDS MAY ALSO BECOME LIGHT ENOUGH TO ALLOW AFTERNOON CONVECTION TO DEVELOP OVER THE ISLANDS. THESE CONVECTION MAY DRIFT WESTWARD UNDER THE TRADE WIND FLOW...BRINGING SOME SHOWERS TO THE LEE AREAS. WINDS WILL SLOWLY TURN MORE SOUTHEAST OVER THE WEEKEND AS A COLD FRONT APPROACHES THE ISLANDS FROM THE NORTHWEST. A SURFACE HIGH PRESSURE RIDGE WILL MOVE NEAR THE ISLANDS AHEAD OF THE APPROACHING COLD FRONT. IN TURN...SURFACE WIND FLOW WILL DECREASE FURTHER...ALLOWING LAND AND SEA BREEZES TO BECOME MORE PROMINENT. FORECAST SOLUTIONS SUGGEST LOW LEVEL MOISTURE IN THE ISLAND VICINITY MAY REMAIN LOW...AND THUS LIMITING THE AMOUNTS OF PRECIPITATION. WITH THE LIGHT WINDS...THE WEATHER WILL PROBABLY FEEL WARM AND MUGGY OVER THE WEEKEND. THERE ARE DIFFERENCES BETWEEN MODELS IN REGARDS TO HOW CLOSE THE APPROACHING FRONT WILL GET TO KAUAI BY EARLY NEXT WEEK. FOR NOW...IT LOOKS LIKE IT WILL BE CLOSE ENOUGH TO BRING SOUTH OR EVEN SLIGHT SOUTHWEST WINDS TO THE WESTERN ISLANDS...WITH POSSIBLE INCREASING SHOWERS FOR KAUAI EARLY NEXT WEEK. && .AVIATION... VIIRS IMAGE FROM 1226Z HIGHLIGHTS THE MVFR/LOCALLY IFR CONDITIONS WHICH HAVE BEEN PERSISTENT ALONG THE N AND E FACING SLOPES OF MAUI AND MOLOKAI THIS MORNING...AS WELL AS SIMILAR CONDITIONS ALONG THE LEE SIDE OF THE BIG ISLAND. CEILINGS HAVE BEEN INTERMITTENTLY BROKEN BETWEEN 500-1000 FEET AT PHOG THIS MORNING AND EXPECT THIS TO CONTINUE UNTIL AFTER DAYBREAK. MT OBSC AIRMET ALSO IN EFFECT FOR N AND E FACING SLOPES OF MAUI...MOLOKAI...AND PARTS OF BIG ISLAND. CONDITIONS SHOULD GRADUALLY IMPROVE AFTER DAYBREAK BUT PREDOMINANT MVFR WILL LINGER IN THOSE AREAS EVEN LONGER. && .MARINE... THE SHORT PERIOD NORTH SWELL WILL LINGER INTO WEDNESDAY BEFORE LOWERING ON THURSDAY. A MEDIUM SIZE LONG PERIOD SOUTH SWELL IS EXPECTED TO BUILD ON THURSDAY AND LIKELY REACH ADVISORY LEVELS ON FRIDAY AND SATURDAY. WINDS WILL REMAIN BELOW SMALL CRAFT CONDITIONS FOR ALL COASTAL WATERS THROUGH REST OF THE WEEK. && .HFO WATCHES/WARNINGS/ADVISORIES... NONE. && $$ AVIATION...R BALLARD REST...HUI  FXHW60 PHFO 111353 AFDHFO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HONOLULU HI 350 AM HST TUE AUG 11 2015 .SYNOPSIS... MODERATE TRADE WINDS ARE EXPECTED TO CONTINUE TODAY. TRADE SHOWERS WILL REMAIN FOCUSED OVER WINDWARD AND MAUKA AREAS...ESPECIALLY OVER PARTS OF THE WINDWARD BIG ISLAND. THE FORECAST FOR MID-WEEK CONTINUES TO DEPEND ON THE FUTURE TRACK AND INTENSITY OF HURRICANE HILDA. ASSUMING HILDA CONTINUES TO APPROACH THE ISLANDS LATER THIS WEEK...HEAVY RAINFALL...THUNDERSTORMS AND FLASH FLOODING MAY OCCUR OVER PORTIONS OF THE STATE. && .DISCUSSION... THE RELATIVELY TIGHT PRESSURE GRADIENT SOUTH OF A NEARLY STATIONARY 1028 MB SURFACE HIGH NEAR 42N 151W...OR ABOUT 1500 MILES NORTH NORTHEAST OF HONOLULU...IS MAINTAINING MODERATE TO LOCALLY BREEZY TRADE WINDS ACROSS THE ALOHA STATE EARLY THIS MORNING. ELSEWHERE... HURRICANE HILDA WAS LOCATED NEAR 17.1N 150.9W...OR ABOUT 330 MILES EAST-SOUTHEAST OF HILO AND ABOUT 540 MILES EAST-SOUTHEAST OF HONOLULU...AT 1100 PM HST MONDAY ACCORDING TO THE CENTRAL PACIFIC HURRICANE CENTER /CPHC/. HILDA WAS MOVING TOWARD THE NORTHWEST AT ABOUT 5 MPH AT THAT TIME. FOR ADDITIONAL INFORMATION ON HILDA... PLEASE SEE THE LATEST ADVISORY UNDER AWIPS HEADER TCPCP5 AND WMO HEADER WTPA35 PHFO. ALOFT...MIDDLE AND UPPER LEVEL LOW PRESSURE AREAS ARE CENTERED ABOUT 500 MILES NORTH OF HONOLULU. A MIDDLE LEVEL TROUGH EXTENDS FROM THE MIDDLE LEVEL LOW TO NEAR KAUAI. SATELLITE IMAGERY AND RADAR REFLECTIVITY DATA SHOW SCATTERED TO BROKEN LOW CLOUDS WITH EMBEDDED ISOLATED SHOWERS OVER THE WINDWARD COASTAL WATERS...ESPECIALLY EAST OF THE WINDWARD BIG ISLAND. NOTE THAT SOME OF THE LOW CLOUDS DUE EAST OF THE BIG ISLAND APPEARED TO DISSIPATE DURING THE PAST COUPLE OF HOURS. THIS MAY BE DUE TO SUBSIDENCE INCREASING AHEAD OF HILDA. THESE LOW CLOUDS AND SHOWERS WILL MAINLY AFFECT WINDWARD AND MAUKA AREAS OF THE STATE TODAY...ESPECIALLY OVER THE WINDWARD BIG ISLAND. THE RELATIVELY STRONG TRADES MIGHT CARRY A FEW BRIEF SHOWERS OVER TO LEEWARD SECTIONS OF SOME OF THE ISLANDS EARLY THIS MORNING...BUT MOST LEEWARD AREAS WILL LIKELY REMAIN DRY LATER TODAY. THE TRADE WINDS ARE EXPECTED TO DROP SLIGHTLY TONIGHT AS THE SURFACE HIGH FAR NORTH-NORTHEAST OF THE ISLANDS WEAKENS SLIGHTLY. IN ADDITION...THE MIDDLE LEVEL TROUGH IN THE VICINITY OF THE ISLANDS WILL ALSO CAUSE THE SURFACE PRESSURE GRADIENT TO WEAKEN SLIGHTLY. AS A RESULT...EXPECT THE TRADE WINDS TO DIMINISH SOMEWHAT TONIGHT. LOW CLOUDS AND SHOWERS WILL REMAIN FOCUSED PRIMARILY ALONG WINDWARD FACING SLOPES AND HIGHER TERRAIN DURING THE NEXT COUPLE OF DAYS... WITH UPSLOPE SECTIONS OF THE LEEWARD BIG ISLAND EXPERIENCING AFTERNOON CLOUD COVER AND SHOWERS. THE 200 AM HST SOUNDING AT HILO CONTINUED TO SHOW THE LOW LEVEL TRADE-WIND INVERSION NEAR 8 TO 9 THOUSAND FEET...WITH PRECIPITABLE WATER /PW/ VALUES NEAR 1.6 INCHES. HOWEVER...THE LIHUE SOUNDING SHOWED NO TRADE WIND INVERSION... POSSIBLY DUE TO CLOSE PROXIMITY OF THE MIDDLE LEVEL TROUGH. THE PW AT LIHUE WAS NEAR 1.7 INCHES. THE GFS MODEL OUTPUT SUGGESTS THERE WILL BE LITTLE CHANGE IN PW VALUES IN THE UPWIND TRADE FLOW THROUGH TONIGHT FOR MOST ISLANDS. WE DO NOT ANTICIPATE SIGNIFICANT HEAVY SHOWERS OVER THE SMALLER ISLANDS. THE EXCEPTION WILL LIKELY BE THE BIG ISLAND...WHERE INCREASING MOISTURE ALONG THE PERIPHERY OF HURRICANE HILDA COULD PRODUCE A MODEST BOOST IN RAINFALL STARTING LATER TODAY OR TONIGHT. FOR WEDNESDAY...UNCERTAINTY INCREASES AS THE LATEST CPHC FORECAST CONTINUES TO SHOW HURRICANE HILDA MAY WEAKEN AS IT APPROACHES THE STATE FROM THE SOUTHEAST. ALTHOUGH HILDA HAS BEEN A RELATIVELY COMPACT TROPICAL CYCLONE...THE LOW LEVEL MOISTURE FIELD SURROUNDING IT IS RATHER BROAD. THIS MEANS THAT THE BIG ISLAND...AND POSSIBLY MAUI...WILL LIKELY SEE AN INCREASE IN SHOWER ACTIVITY EVEN WHEN HILDA IS A FEW HUNDRED MILES AWAY BASED ON THE CURRENT FORECAST TRACK AND INTENSITY FOR THIS SYSTEM. THE TRADE WINDS WILL LIKELY HOLD INTO WEDNESDAY WITH A GOOD CHANCE FOR A GRADUAL INCREASE IN SHOWER ACTIVITY SPREADING FROM EAST TO WEST OVER THE ISLANDS. IN ADDITION...PERIODS OF LOCALLY HEAVY SHOWERS WILL BE POSSIBLE ON BIG ISLAND SLOPES...ESPECIALLY DURING THE AFTERNOON. FOR THURSDAY THROUGH SATURDAY...FORECAST UNCERTAINTY ASSOCIATED WITH HILDA REMAINS HIGH. NO MATTER WHAT THE INTENSITY OF THE SYSTEM WILL BE...HEAVY RAINFALL AND FLASH FLOODING WILL BE POSSIBLE. A HYDROLOGIC OUTLOOK HAS BEEN ISSUED TO HIGHLIGHT THIS POTENTIAL THREAT...AND FLASH FLOOD WARNINGS MAY NEED TO BE ISSUED FOR PORTIONS OF THE STATE LATER THIS WEEK. ALL INTERESTS IN THE STATE OF HAWAII SHOULD KEEP MONITORING THE PROGRESS OF HILDA BY TUNING IN TO NOAA WEATHER RADIO...LOCAL MEDIA OUTLETS OR BY VISITING OUR WEBSITE AT WWW.WEATHER.GOV/HAWAII FOR THE LATEST BULLETINS AND WEATHER PRODUCTS. HILDA...OR ITS REMNANTS...WILL MOST LIKELY BE CLEARING THE STATE SOMETIME DURING THE WEEKEND. && .AVIATION... AIRMET TANGO WAS DROPPED AROUND MIDNIGHT AS VAD WIND PROFILE DATA SHOWED WINDS WERE ON THE DECLINE. ENHANCED MOISTURE ASSOCIATED WITH THE EXTREME WESTERN PORTION OF HILDA ARE MOVING OVER THE COASTAL WATERS TO THE EAST OF THE BIG ISLAND...AND OVER THE EASTERN PORTION OF THE BIG ISLAND THIS MORNING. SOME MVFR CONDITIONS ARE FOUND OVER THIS AREA...BUT A RECENT VIIRS DAY/NIGHT BAND SATELLITE IMAGE SHOWS VFR CONDITIONS PREVAIL OVER MOST OF THE ISLAND. EXPECT PERIODS OF MVFR AND ISOLATED IFR CONDITIONS IN SOME OF THE CLOUDS AND SHOWERS THAT WILL CONTINUE TO BE CARRIED IN ON THE TRADE WINDS. AN AIRMET FOR MOUNTAIN OBSCURATION MAY BE NEEDED LATER TODAY. ELSEWHERE...THE TRADE WINDS WILL FOCUS CLOUDS AND SHOWERS OVER WINDWARD AND MOUNTAIN AREAS. SOME SHOWERS WILL LIKELY CARRY PERIODS OF MVFR. && .MARINE... WITH THE MOST RECENT FORECAST FOR THE TRACK...INTENSITY AND SIZE OF HURRICANE HILDA...THE TROPICAL CYCLONE WIND PROBABILITIES SHOW THAT THE COASTAL WATERS ADJACENT TO THE BIG ISLAND MAY HAVE TROPICAL STORM CONDITIONS WITHIN THE NEXT 48 HOURS. AS A RESULT...WE ARE ISSUING A TROPICAL STORM WATCH FOR THE WATERS SURROUNDING THE BIG ISLAND...EXCLUDING THE ALENUIHAHA CHANNEL. ELSEWHERE...ALL INTERESTS...ESPECIALLY MARINERS...IN THE STATE OF HAWAII SHOULD KEEP MONITORING THE PROGRESS OF HILDA BY LISTENING TO THE NOAA WEATHER RADIO...LOCAL MEDIA OUTLETS OR VISITING OUR WEBSITE AT WWW.WEATHER.GOV/HAWAII. THE SMALL CRAFT ADVISORY /SCA/ FOR THE TYPICALLY WINDY WATERS ADJACENT TO THE ISLANDS OF MAUI COUNTY AND THE ALENUIHAHA CHANNEL HAS BEEN EXTENDED UNTIL EARLY THIS EVENING. BASED ON THE LATEST MODEL GUIDANCE...THE TRADES MAY NOT WEAKEN OVER THESE TYPICALLY WINDY WATERS UNTIL TONIGHT. EAST-SOUTHEAST SWELL FROM HILDA HAS CONTINUED TO BUILD OVERNIGHT... ESPECIALLY ALONG THE SOUTHEAST FACING SHORES OF THE BIG ISLAND. SINCE WE HAD REPORTS OF LARGE SURF LATE MONDAY ALONG SOME OF THE BEACHES OF THE BIG ISLAND...WE HAVE DECIDED TO ISSUE A HIGH SURF WARNING FOR THE EAST FACING SHORES OF THAT ISLAND THROUGH TONIGHT. THE HIGH SURF ADVISORY FOR EAST FACING SHORES OF EAST MAUI CONTINUES THROUGH TONIGHT. WE MAY NEED TO EXTEND THE HIGH SURF ADVISORY INTO WEDNESDAY BASED ON THE FUTURE TRACK AND INTENSITY OF HILDA. ALTHOUGH THE OTHER SMALLER ISLANDS WEST OF MAUI MAY REMAIN MOSTLY BLOCKED FROM THE HILDA SWELL DURING THE NEXT SEVERAL DAYS...SOME REFRACTED SWELL ENERGY WILL LIKELY AFFECT EAST FACING BEACHES AND NEARSHORE REEFS...WHILE LARGER SWELLS WILL LIKELY BE EXPERIENCED FARTHER OFFSHORE. && .HFO WATCHES/WARNINGS/ADVISORIES... HIGH SURF WARNING UNTIL 6 AM HST WEDNESDAY FOR EAST FACING SHORES OF THE BIG ISLAND. HIGH SURF ADVISORY UNTIL 6 AM HST WEDNESDAY FOR EAST FACING SHORES OF EAST MAUI. TROPICAL STORM WATCH FOR THE BIG ISLAND WINDWARD WATERS...BIG ISLAND LEEWARD WATERS...AND BIG ISLAND SOUTHEAST WATERS. SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR MAALAEA BAY...AND THE PAILOLO AND ALENUIHAHA CHANNELS. && $$ DISCUSSION/MARINE...HOUSTON AVIATION...M BALLARD  FXHW60 PHFO 101403 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 403 AM HST Thu Nov 10 2016 .SYNOPSIS... A weak surface ridge near the islands will maintain light winds across the region through the end of the week. With a relatively stable pattern over the islands, the light winds will create afternoon clouds over interior sections with spotty, light showers, followed by clearing at night. Trade winds will rebuild on Sunday and could become breezy and gusty on Monday. && .DISCUSSION... No significant change to the forecast this morning. The overnight soundings from Hilo and Lihue continue to show low inversions, with heights between 4000 and 5500 ft, and precipitable water (PW) values between 1.34 and 1.44 inches, which is about normal for December. The surface ridge is over the smaller islands, bringing light winds to the region, which helped to clear skies over most of the islands overnight. A recent VIIRS Day/Night band image, which uses the available moonlight to produce a pseudo visible image, showed few clouds over the islands. Expect clouds to form over the interior of the islands starting around mid morning, with some spotty showers this afternoon. Rainfall totals are expected to remain light. A dissipating frontal band north of Kauai could bring a few more showers into Kauai this afternoon, but is otherwise not expected to have an impact on the island weather. The ridge is expected to linger overhead through Saturday, with a new high pressure system building far north of the islands on Sunday. This will bring trades back to the islands, which are expected to increase further on Monday. The return to trades will also bring a return to the more typical trade wind showers. The models show winds atop the Big Island summits will be picking up early next week. Have made some tweaks to the forecast winds for Monday onwards to better account for the latest model runs. && .AVIATION... The tail end to a front poses a threat to northern Kauai this morning where associated clouds are moving toward the island. The models have the clouds breaking up over the waters before reaching the northern coast this morning. But if the clouds do make it onshore and coverage is widespread, we may need to impose AIRMET Sierra for mountain obscuration. At this time, however. we will go with models suggestion of keep northern Kauai VFR. Otherwise, VFR will rule the island skies today. Light winds and daytime heating, however, will combine to produce some spotty afternoon clouds over the island's interior areas. Any MVFR ceilings that arises will be local, and the showers will be isolated and brief at best. Light trades will be returning tonight accompanied by some trade wind clouds. No AIRMETS in effect and none is expected. && .MARINE... We are starting to see hints of the new long period north northwest swell at buoys 51000 and 51001. Travel time to the Kauai is about 6 hours, it'll be sometime this morning before that energy even begins to reach the islands. As the swell builds today, expect the elevated surf to rise again to warning levels late in the date. A high surf warning has been issued for various north and west facing shores while a high surf advisory is in effect for the Big Island and Oahu. The current advisory/warning goes out until 6 am Friday, but in all likelihood will be extended as the surf is expected to remain elevated. Another large northwest swell is expected to arrive Sunday night with surf reaching at least advisory levels. Winds will remain below small craft advisory (SCA) criterion through Saturday. As the trades pick up early next week, a SCA for winds may be needed. Meanwhile the incoming swell will boost seas above 10ft for many locations later today. As such, an SCA have been issued for most coastal locations. && .HFO WATCHES/WARNINGS/ADVISORIES... High Surf Warning until 6 AM HST Friday for Niihau-Kauai Windward-Kauai Leeward-Oahu North Shore-Oahu Koolau-Olomana- Molokai-Maui Windward West-Maui Central Valley-Windward Haleakala. High Surf Advisory until 6 AM HST Friday for Waianae Coast-Big Island North and East. Small Craft Advisory from 11 AM this morning to 6 PM HST Friday for Kauai Northwest Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-Oahu Windward Waters-Oahu Leeward Waters- Kaiwi Channel-Maui County Windward Waters-Alenuihaha Channel-Big Island Windward Waters. Small Craft Advisory from 6 PM this evening to 6 PM HST Friday for Maui County Leeward Waters-Pailolo Channel-Big Island Southeast Waters. && $$ DISCUSSION/MARINE...M Ballard AVIATION...Lau  FXHW60 PHFO 111339 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 339 AM HST Wed Jan 11 2017 .SYNOPSIS... Daytime sea breezes and nighttime land breezes will continue through the remainder of the week and into the weekend. A front will stall northwest of the state late tonight and Thursday, bringing increasing showers to Kauai, and higher humidity to the rest of the islands. Volcanic haze, or vog, will affect most areas through Saturday. Trade winds should gradually return to the islands early next week. && .DISCUSSION... Dry conditions prevail across the state on this early Wednesday morning. Radar shows only isolated light showers over the central coastal waters, and rain gauges around the state report almost no rainfall during the past 6 hours. Surface analysis depicts a high pressure ridge just north of Kauai, with a dissipating front to the north of the ridge. Light east to southeast synoptic winds prevail over the state to the south of the ridge, with land breezes prevailing over the islands. Aloft, a weak upper level trough just west of the state is generating scattered to broken cirrus cloudiness over the central and eastern islands. The 12Z soundings show a dry and stable atmosphere remaining in place, with PW values just over one inch and strong inversions based near 5000 feet. MIMIC-TPW satellite imagery also shows a similarly dry airmass over the state, with somewhat greater moisture over the waters to the south through west of Kauai. A rather stagnant pattern is forecast to prevail over the state through the next several days. Persistent mid level ridging to the east and south of the islands will prevent frontal systems from moving through the state, while a nearby surface ridge axis will maintain light background winds with land and sea breeze circulations dominating. The next front, currently about 800 miles northwest of Kauai, will approach the region today, then stall about 300 miles northwest of Kauai late tonight and Thursday. Increased shower activity due to pre-frontal convergence may affect Kauai tonight and Thursday, otherwise mainly dry conditions should continue. Weaker inversions over Oahu and possibly into Maui County may allow for a bit more afternoon shower activity along seabreezes Thursday afternoon. The dissipating front will linger northwest of Kauai on Friday, then retreat back northward during the weekend. The surface ridge axis will move slowly northward as well, with trade winds edging back into at least eastern parts of the state by Sunday afternoon. Generally dry and mild weather will continue during the weekend, as another weak front passes north of the state. Heading into next week, models show a building mid level ridge over the islands, with the surface ridge axis gradually easing further north and rather dry trade winds building across the state. Longer range models show the next front stalling far to the northwest of Kauai early next week. Volcanic haze, or vog, will remain over the state through Saturday. Light southeast flow will push volcanic emissions from Kilauea on the southeast side of the Big Island to many areas across the state. Returning trade winds should gradually clear the vog out early next week. && .AVIATION... A VIIRS Day/Night band pass over Hawaii early this morning showed relatively quiet conditions with broken low clouds over the south shore of Oahu and from Hilo south through the Kau district on the Big Island. Observations from PHNL and PHTO show the bases remaining well within VFR criteria. Elsewhere, land breezes have cleared most low level clouds from the islands. An upper level trough moving from west to east across the island chain continues to produce scattered to broken cirrus from Oahu to the Big Island. Cirrus should push off east of the islands by this afternoon. The light southeast background flow will veer more south today, mainly near the western islands, as an approaching front pushes the ridge across the islands. However, the background flow will remain light enough to allow for the development of sea breezes. Clouds and showers will favor the interior land areas today, although any showers should remain brief under the dry and stable atmosphere. Expect VFR conditions to prevail. The background southeast and south flow has also helped carry the volcanic emission north over the smaller islands, and creating hazy skies. The approaching front will start to introduce a bit more moisture and a rise in the inversion level near Kauai as early as this evening. && .MARINE... A very active pattern across the northwest Pacific will correspond to a few periods with surf exceeding the 25 ft (face value) warning- level threshold along the exposed northern and western shores of the Hawaiian Islands within the upcoming five to 10 days. The first episode will likely fill in Friday (possibly as early as daybreak Friday for Kauai) and hold into Friday night before easing through the weekend and into early next week. A second round will become a possibility next week at some point between late Tuesday and Thursday (timing and magnitude remain uncertain this far out for this event due to model differences and the potential for large changes over the coming days). The latest surface analysis supported this potential and showed a storm-force low (987 mb) centered around 1500 nautical miles northwest of the islands and a developing gale to its west a few hundred miles east of Japan. A recent ASCAT pass reflected these features and showed a large batch of gale-to-storm (40 to 50 kt) force winds out of the west-northwest south of this low aimed at the islands. The latest ensemble and deterministic model guidance have initialized well with this evolving pattern and depict these features tracking toward the east-northeast across the Date Line over the Date Line today, then to a position south-southwest of Kodiak Thursday through Friday. The wave model guidance is now in good agreement with the timing and magnitude and depict a peak Friday through Friday night here in the islands. Peak locations will likely see surf well above the warning level (25 ft faces) through this time Friday, then down to advisory-levels through the day Saturday before easing further. A smaller northwest swell will fill in later today and hold through Thursday. This source should remain just below the advisory level through this period along the exposed northern and western shores. However, the outlier is the ECMWF-WAVE guidance, which depicts a slightly larger solution through this time that could correspond to surf heights nearing the advisory mark (15 ft) by tonight. A north-northeast swell associated with a recent system in the Gulf of Alaska is expected to correspond to peak surf along north and east facing shores through the day today at levels just below the advisory mark of eight ft along the eastern shores. This source will then ease through the rest of the week. Small surf associated with a long-period southerly swell will be expected through Friday along the southern shores of the islands due to recent activity over the southern Pacific. Local winds are forecast to remain light through the upcoming weekend with land ans sea breezes each day as a ridge of high pressure remains over the islands. Moderate to fresh trades are forecast to return by the mid-week period next week as high pressure builds north of the state. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Jacobson AVIATION...Eaton MARINE...Gibbs