Prognostic Meteorological Discussion
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FXHW01 KWNH 051219
PMDHI

HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
819 AM EDT THU MAY 05 2016

VALID 00Z FRI MAY 06 2016 - 00Z FRI MAY 13 2016

AN UPPER TROUGH AND EMBEDDED UPPER LOW THAT WILL CLOSE OFF DURING
THE DAY FRI WILL TRACK TO THE NORTH OF THE STATE, PUSHING A FRONT
INTO THE ISLANDS LATE THIS WEEK.  THE FRONT AND ASSOCIATED BAND OF
MOISTURE, WITH PRECIPITABLE WATER VALUES PERHAPS AS HIGH AS 1.50
INCHES OR SO AT TIMES, WILL LIKELY BECOME STALLED OVER THE
SOUTHEASTERN HALF OF THE ISLANDS DURING THE WEEKEND AND INTO NEXT
WEEK.  AS A RESULT THIS PART OF THE STATE WILL SEE POTENTIAL FOR
INCREASED RAINFALL, EITHER FROM LOCALIZED HEAVIER DOWNPOURS OR
FROM THE MULTI-DAY ACCUMULATION OF PERSISTENT BUT LESS INTENSE
ACTIVITY.  ONE OR MORE WEAK SHORTWAVE IMPULSES DRIFTING INTO THE
REGION FROM THE WEST MAY HELP TO ENHANCE RAINFALL AS WELL.  THE
FRONT WILL SEPARATE LEADING SOUTHEASTERLY/EASTERLY WINDS FROM
NORTHEASTERLY LOW LEVEL FLOW.

MODEL/ENSEMBLE GUIDANCE AGREES WITH MOST ASPECTS OF THE FORECAST.
HOWEVER BY EARLY NEXT WEEK THE 00Z GEFS MEAN BECOMES MORE
AMPLIFIED THAN OTHER SOLUTIONS WITH THE UPPER TROUGH EXTENDING
SOUTHWARD/SOUTHWESTWARD TOWARD THE ISLANDS AND BY NEXT THU THE 00Z
ECMWF/ECMWF MEAN HOLD BACK UPPER TROUGHING A BIT RELATIVE TO OTHER
SOLUTIONS.  THE ECMWF SCENARIO WOULD KEEP THE BAND OF HIGHER DEEP
MOISTURE OVER THE SOUTHEASTERN HALF OF THE STATE FOR A LONGER
PERIOD OF TIME.  AT THIS THIS TIME THERE DOES NOT APPEAR TO BE A
COMPELLING SIGNAL TO FAVOR ONE SCENARIO OVER THE OTHER AND IN THE
PAST DAY BOTH CLUSTERS HAVE MAINTAINED CONTINUITY.  THEREFORE
WOULD RECOMMEND AN INTERMEDIATE APPROACH IN THE LATTER PART OF THE
FORECAST PERIOD AFTER FOLLOWING A NON-00Z GEFS CONSENSUS EARLY IN
THE WEEK.

RAUSCH

$$





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