000 FXHW60 PHFO 090128 CCA AFDHFO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HONOLULU HI 330 PM HST WED SEP 8 2010 .SYNOPSIS... HIGH PRESSURE NORTH OF THE STATE WILL PRODUCE MODERATE TRADE WINDS THROUGH THE UPCOMING WEEK. SHOWERS WILL FAVOR WINDWARD AND MOUNTAIN AREAS WITH MAINLY LIGHT RAINFALL. A BRIEF INCREASE IN RAINFALL WILL OCCUR THURSDAY NIGHT THROUGH FRIDAY MORNING. && .DISCUSSION... NO CHANGES TO THE ONGOING FORECAST REASONING FROM THIS MORNING. ONLY MADE SOME MINOR TWEAKS AND ADJUSTMENTS TO THE SHORT TERM. MODERATE TRADE WINDS WITH LOCALLY FRESH GUSTS ARE EXPECTED THROUGH THE PERIOD. A SLIGHT AND SHORT LIVED INCREASE IN WINDWARD RAINFALL WILL BEGIN LATE THURSDAY AFTERNOON AND CONTINUE THROUGH FRIDAY MORNING AS A MOISTURE AXIS CROSSES THE STATE. PWAT VALUES TO 1.4 INCHES SUPPORTS 80-100 POPS FOR WINDWARD ZONES. MAINLY LIGHT RAINFALL EXPECTED HOWEVER EMBEDDED MODERATE SHOWERS AND EVEN A SPOTTY BRIEF DOWNPOUR IS POSSIBLE. FRIDAY AFTERNOON THROUGH THE END OF THE PERIOD DRIER TRADE FLOW RETURNS WITH TYPICAL DIURNAL FLUCTUATIONS IN POPS/WIND. && .PREVIOUS DISCUSSION.../ISSUED 930 AM HST WED SEP 08/ NOT EXPECTING ANY SIGNIFICANT CHANGES TO THE FORECAST DURING TODAYS SHIFT. BROAD HIGH PRESSURE REMAINS IN CONTROL OVER THE EASTERN NORTH PACIFIC THIS MORNING. WATER VAPOR IMAGERY REVEALS THAT DEEPER LAYERED HIGH PRESSURE REMAINS PUNCTUATED BY MID LEVEL LOW PRESSURE DOCKED JUST NORTH OF THE STATE. THIS IS KEEPING POTENTIALLY STRONGER TRADES IN CHECK WITH LIGHT TO MODERATE SPEEDS. PRECIPITABLE H20 IMAGERY DEPICTS A NARROW AXIS OF HIGHER BOUNDARY LAYER MOISTURE JUST UPSTREAM TO THE EAST MOVING WESTWARD IN THE TRADE FLOW. THIS WILL REACH THE STATE LATER TOMORROW AFTERNOON BRIEFLY INCREASING WINDWARD SHOWER CHANCES THROUGH FRIDAY MORNING. HAWAII WILL REMAIN SITUATED ON THE ANTICYCLONIC SIDE OF THE SUBTROPICAL JET AXIS NORTHWEST OF THE STATE. THIS WILL LEAD TO FLUCTUATING AMOUNTS OF CIRRUS DEBRIS PASSING OVER THE STATE...MAINLY ACROSS KAUAI/OAHU...DURING THE NEXT SEVERAL DAYS DEPENDENT ON THE COINCIDENT INTENSITY/COVERAGE OF ITCZ CONVECTION TO THE SOUTH. FOR THE WEEKEND THROUGH THE REMAINDER OF THE FORECAST PERIOD OPERATIONAL GUIDANCE AND ENSEMBLES SUGGEST MORE OF THE SAME. HIGH PRESSURE REMAINS DOMINANT OVER THE EASTERN NORTH PACIFIC MAINTAINING MOSTLY MODERATE TRADES ACROSS THE STATE. SOME OF THE WINDIER AREAS AND COASTAL ZONES COULD REACH LOCALLY FRESH LEVELS AT TIMES. SHOWERS WILL REMAIN FOCUSED ON WINDWARD TERRAIN WITH THE NORMAL DIURNAL FLUCTUATIONS AND HIGHEST POPS OVERNIGHT. TEMPS STAY CONSISTENT AND NEAR NORMAL TOPPING OUT IN THE HIGH 80S WHILE LOWS HOVER IN THE LOW 70S. && .MARINE... TRADE WINDS OVER HAWAIIAN WATERS WILL HOLD AT MODERATE TO LOCALLY FRESH STRENGTH THROUGH THE WEEKEND. ONLY SLIGHT FLUCTUATIONS IN SPEED ARE EXPECTED. SOME OF THE TYPICALLY WINDIER COASTAL ZONES AROUND MAUI/HAWAII COUNTIES MAY OCCASIONALLY NEAR SCA CRITERIA HOWEVER NOT ANTICIPATING ANY MARINE ADVISORIES IN THE COASTAL WATERS. SURF REMAINS ON THE SMALL SIDE AROUND THE ISLAND. WINDWARD SHORES ARE SEEING THE LARGEST SURF WITH SOME OCCASIONAL CHEST HIGH SETS IMPACTING SOME REEFS. SOUTH FACERS CONTINUE TO PULL IN SMALL BACKGROUND SWELL UP TO WAIST HIGH WITH CLEAN CONDITIONS EARLY. THE SURF SITUATION IS LOOKING UP FOR THE WEEKEND. SURF MAY BEGIN TO INCREASE LATE FRIDAY AFTERNOON...BUT SATURDAY AND SUNDAY ARE LOOKING LIKE THE DAYS. FRESH SOUTHERN HEMISPHERE SWELL 190-205 WILL FILL IN PRODUCING SOME WAIST TO CHEST HIGH SURF FOR SELECT SOUTH SHORE REEFS. THIS SWELL WILL TAPER OFF SUNDAY INTO MONDAY JUST AS ANOTHER MODEST BURST OF SWELL ARRIVES MONDAY NIGHT INTO TUESDAY WITH SIMILAR SIZE. OVER THE NEXT 24-36 HOURS ANOTHER POTENT SHORT WAVE WILL ROTATE THROUGH THE MEAN SOUTH PACIFIC TROUGH WELL EAST OF NEW ZEALAND. THIS WILL CREATE A CAPTURED FETCH OF STRONG TO SEVERE GALES AIMED NORTH-NORTHEAST. THIS WILL TAKE BETTER AIM AT THE NORTH AND CENTRAL AMERICA HOWEVER ANGULAR SPREADING SHOULD PROVIDE SOME MODERATE SWELL TOWARDS THE MIDDLE OF NEXT WEEK BEGINNING LATE ON THE 15TH AND LASTING FOR A COUPLE DAYS TOPPING OUT AROUND HEAD HIGH OR SO. NOT EXPECTING ANY SWELL WORTH MENTIONING FOR NORTH FACING SHORES IN THE NEXT WEEK TO TEN DAYS. ANY SHORT WAVES EMERGING OFF THE NORTHEAST ASIAN COAST WILL BE MOVING NORTHEAST QUICKLY AND SKIPPING THROUGH HAWAIIAN GREAT CIRCLE ROUTES TOO FAST TO PRODUCE ANY SURF LOCALLY. && .AVIATION... NO AIRMETS ARE IN EFFECT OVER THE STATE THIS AFTERNOON. PHTO MAY TEMPORARILY GO TO MVFR TODAY DUE TO APPROACHING SHOWERS AND CLOUDS UPSTREAM OF THE BIG ISLAND. ELSEWHERE...VFR CONDITIONS WILL PREVAIL. && .FIRE WX... RH VALUES AT PHNL HAVE REACHED AS LOW AS 43 PERCENT ALREADY LATE THIS MORNING. WINDS ARE REMAINING WELL OUT OF RED FLAG RANGE. NO RED FLAG WARNINGS OR FIRE WX WATCHES ARE EXPECTED IN THE NEAR FUTURE. HOWEVER...GIVEN PERSISTENT DROUGHT FUELS WILL REMAIN ABUNDANT SO CONDITIONS REMAIN SOMEWHAT FAVORABLE FOR RAPID FIRE GROWTH...ESPECIALLY IN SOME THE LOCALLY GUSTY LEEWARD AREAS. && .HFO WATCHES/WARNINGS/ADVISORIES... NONE. && $$ PUBLIC/MARINE/FIRE WX...DEJESUS AVIATION...HARRISON/FUJII
NWS HFO Office Area Forecast Discussion
