HAWAII EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
659 AM EST TUE JAN 20 2009
 
VALID 00Z WED JAN 21 2009 - 00Z WED JAN 28 2009
 



CURRENT SEMIZONAL PAC FLOW WITH THE ISLANDS UNDER THE SRN FRINGE
OF THE PAC WESTERLIES WILL GIVE WAY TO A HIGHLY AMPLIFIED PATTERN
WITH RIDGING BUILDING OVER AND NE OF THE ISLANDS AND A DEEP TROF
AND POTENTIAL CUTOFF LOW FORMING TO THE NORTHWEST. GOOD MODEL
AGREEMENT ON THIS EVOLUTION.
FRONT COMING THRU THE REGION TODAY WILL BE FOLLOWED BY HIGH
PRESSURE BUILDING N OF THE ISLANDS WED THEN NEWD AND SETTLING IN
NEAR 40N 140W OVER THE WEEKEND AND EARLY NEXT WEEK. THIS WILL
BRING A TRADE RETURN FOR SEVERAL DAYS WHICH MAY WELL BE DISRUPTED
OVER WRN PORTIONS OF THE ISLANDS AS POTENTIAL CLOSED TO CUTOFF MID
LEVEL FORMS WITH A FAIRLY STRONG SFC REFLECTION. A MOSTLY N-S
ORIENTED FRONT MAY LINGER OR ONLY VERY SLOWLY PROGRESS EWD OVER
WRN PORTIONS LATE IN THE PERIOD. CURRENT GFS PCPN GUIDANCE
INDICATES SOME SHOWERS WITH THE CURRENT FRONT FOLLOWED BY DRY
CONDS EXCEPT FOR SOME WINDWARD SHOWERS WITH TRADE FLOW LATER IN
THE WEEK. POTENTIAL FOR HVIER RAINS MAY AFFECT FAR NW PORTIONS MON
AND TUES
ROSENSTEIN