High Wind in Hawaii, November 19, 2003

HAWAIIAN ISLANDS FORECAST DISCUSSION...AMENDED
NATIONAL WEATHER SERVICE HONOLULU HI
630 AM HST WED NOV 19 2003

UPDATED FOR FRONTAL POSITION AND ASSOCIATED WEATHER

.SYNOPSIS...A WEAKENING COLD FRONT IS PASSING OVER THE ISLANDS THIS
MORNING...BRINGING A FAIRLY STEADY RAINFALL TO MUCH OF THE STATE...
WITH SCATTERED SHOWERS EVEN OVER LEE AREAS. A KONA LOW WILL MOVE
TOWARDS THE ISLANDS FROM THE NORTHEAST OVER THE NEXT FEW DAYS...
EVENTUALLY BRINGING ANOTHER PERIOD OF SHOWERS MONDAY AND TUESDAY.
STRONG AND GUSTY WINDS WITH AND RIGHT BEHIND THE FRONT WILL WEAKEN
AND SHIFT TO THE NORTH AND LATER NORTHWEST BY THE WEEKEND. LIGHTER
WINDS WILL ACCOMPANY THE LOW AS IT MOVES OVER THE STATE EARLY NEXT
WEEK.

&&

.DISCUSSION...THE FRONT IS NOW OVER THE STATE...BUT SHOULD MOVE TO
OUR SOUTH DURING THE AFTERNOON AND TONIGHT. THUS THE WIDESPREAD
RAINFALL THIS MORNING SHOULD GRADUALLY IMPROVE DURING THE
AFTERNOON...WITH ONLY SCATTERED SHOWERS EXPECTED BY THURSDAY. THE
FORECAST FOR DAYS SIX AND SEVEN IS NOW WETTER HOWEVER AS THE MODELS
HAVE ONCE AGAIN PICKED UP ON A KONA LOW FORMING NORTHEAST OF THE
STATE THEN MOVING OVER THE STATE EARLY NEXT WEEK. WHILE A 1045 MB
HIGH NORTH OF 40N HAS STEEPENED THE PRESSURE GRADIENT BEHIND THE
COLD FRONT NOW OVER THE STATE SUFFICIENTLY TO SUPPORT 20 TO 30 MPH
WINDS...THE DEVELOPMENT OF THE KONA LOW SHOULD LIMIT THE TIME STRONG
WINDS WILL BE AFFECTING THE STATE.

THIS KONA LOW FORECAST IS CONFIRMED BY THE DEVELOPMENT OF A LOW
ALONG THE FRONT FAR NORTHEAST OF THE MAIN HAWAIIAN ISLANDS. THIS
LOW IS FORECAST TO BECOME STRONGEST AT MID-LEVELS OF THE
ATMOSPHERE...THUS EVENTUALLY FORMING A CLASSIC KONA LOW AS IT MOVES
SOUTHWEST TOWARDS THE ISLANDS. THROUGH THE SYNOPTIC PROCESS OF
DISCONTINUOUS RETROGRESSION...THE LOW WILL BE PASSED FROM ONE
SHORTWARD NORTHEAST OF THE STATE TO ANOTHER DIGGING SOUTH JUST WEST
OF THE STATE. THIS WILL BRING THE EFFECTS OF THE LOW OVER THE STATE
EARLY NEXT WEEK...WITH THE ACCOMPANYING BANDS OF SURFACE CONVERGENCE
AND INSTABILITY BRINGING POSSIBLE HEAVY RAINFALL TO SOME PARTS OF
THE STATE.

&&

.MARINE...AS THE FRONT MOVES THROUGH THE ISLANDS TODAY...GALE FORCE
WINDS ARE LIKELY IN THE ALENUIHAHA CHANNEL. THE VERY STEEP PRESSURE
GRADIENT BETWEEN THE HIGH AND THE APPROACHING LOW WILL PRODUCE AN
AREA OF NORTHEASTERLY STORM FORCE WINDS NORTHEAST OF THE
ISLANDS...WHICH WILL SEND LARGE OCEAN SWELLS TOWARDS THE STATE. THIS
HAS PROMPTED THE ISSUANCE OF A HIGH SURF ADVISORY FOR EAST AND
NORTHEAST FACING SHORES...AND WILL PROBABLY REQUIRE A HIGH SURF
WARNING WITH LEVELS OF 15 FEET LIKELY BY THURSDAY. THE SWELL WILL
ALSO CAUSE STRONG SURGES IN NORTH FACING HARBORS SUCH AS THE KAHULUI
AND HILO HARBORS.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
GALE WARNING FOR THE ALENUIHAHA CHANNEL
SMALL CRAFT ADVISORY FOR ALL HAWAIIAN WATERS
HIGH SURF ADVISORY FOR EAST AND NORTHEAST FACING SHORES

&&

FARRELL