Prognostic Meteorological Discussion
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000
FXHW01 KWNH 271215
PMDHI

HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
714 AM EST THU NOV 27 2014

VALID 00Z FRI NOV 28 2014 - 00Z FRI DEC 05 2014

FROM NOW THROUGH ABOUT MON A GENERAL BLEND OF MODEL/ENSEMBLE
GUIDANCE SHOULD PROVIDE A REASONABLE STARTING POINT FOR THE
FORECAST GIVEN FAIRLY MINOR DIFFERENCES AT THE SURFACE AND ALOFT.
DURING THIS PERIOD HIGH PRESSURE WELL NORTH OF THE ISLANDS WILL
SUPPORT FAIRLY BRISK TRADES, THOUGH WITH A GRADUAL SLACKENING
TREND AS THE HIGH WEAKENS AND TRACKS EASTWARD.  EXPECT
WINDWARD-FAVORED SHOWERS TO BE ON THE LIGHT SIDE WITH PRECIPITABLE
WATER VALUES NEAR OR BELOW AN INCH OVER CENTRAL/NORTHERN ISLANDS,
AND EVEN THE BIG ISLAND BY SUN-MON.  THE FORECAST BECOMES MORE
UNCERTAIN BY TUE-THU AS DIFFERENCES ALOFT AFFECT THE SURFACE
GRADIENT AS WELL AS HOW MUCH MOISTURE INCREASES OVER THE ISLANDS.
GIVEN TYPICAL GUIDANCE ERRORS IN THE DAYS 5-7 TIME FRAME, A
COMPROMISE BETWEEN THE 00Z GEFS AND ECMWF ENSEMBLE MEANS SHOULD
PROVIDE THE MOST MODERATE SOLUTION WITH RESPECT TO THE
TIMING/SHAPE OF SHORTWAVE ENERGY ALOFT, DEGREE OF INCREASE IN DEEP
MOISTURE, AND THE STRENGTH OF THE SURFACE GRADIENT/TRADES.

RAUSCH

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