Prognostic Meteorological Discussion
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FXHW01 KWNH 211204
PMDHI

HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
804 AM EDT MON AUG 21 2017

VALID 00Z TUE AUG 22 2017 - 00Z TUE AUG 29 2017

THROUGH TUESDAY EXPECT AN INVERTED UPPER TROUGH (LIKELY CONTAINING
A LOW CENTER TO THE NORTH-NORTHWEST OF THE STATE) PLUS FAIRLY HIGH
PRECIPITABLE WATER VALUES TO PROMOTE SOME ENHANCED SHOWER
ACTIVITY.  THEN A DRIER TREND WILL COMMENCE AS THE UPPER FEATURE
AND DEEP MOISTURE CONTINUE WESTWARD.  BY NEXT MONDAY MODEL
DIFFERENCES EMERGE REGARDING A POTENTIAL INCREASE OF MOISTURE
COMING INTO THE BIG ISLAND AND VICINITY, WITH 00Z/06Z GFS RUNS
BEING SOMEWHAT QUICKER THAN THE PAST COUPLE ECMWF RUNS.  THE 00Z
GEFS MEAN IS SLIGHTLY SLOWER THAN THE GFS RUNS WITH THE MOISTURE`S
ARRIVAL, SO A COMPROMISE APPEARS TO BE A REASONABLE FORECAST AT
THIS TIME.  OVER THE COURSE OF THE PERIOD TRADES WILL FLUCTUATE IN
RESPONSE TO EVOLUTION/PROGRESSION OF MID-LATITUDE HIGH PRESSURE,
TENDING TO BE IN THE MODERATE RANGE OVERALL.  THE MAJORITY OF
SHOWER ACTIVITY SHOULD BE WINDWARD-FOCUSED.  A LITTLE SEA-BREEZE
INFLUENCE MAY BE POSSIBLE DURING PERIODS OF RELATIVELY LIGHTER
TRADE FLOW FROM NOW INTO TUESDAY AND DURING FRIDAY-SATURDAY.

RAUSCH

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