Prognostic Meteorological Discussion
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FXHW01 KWNH 261219
PMDHI

HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
718 AM EST FRI DEC 26 2014

VALID 00Z SAT DEC 27 2014 - 00Z SAT JAN 03 2015

THE 26/00Z ECENS/GEFS AND THEIR DETERMINISTIC SOLUTIONS WERE A TAD
SLOWER/FASTER RESPECTIVELY THAN THEIR 25/00Z SOLUTIONS---BUT
MAINTAIN A MID-LEVEL TROUGH MIGRATION ACROSS HAWAI`I BETWEEN
31/00Z AND 1/00Z. THIS IS CONSISTENT WITH THE 25/00Z CYCLE BUT THE
DETERMINISTIC 26/00Z GFS CONTINUES TO BE THE FASTER SOLUTION IN
THE SUBTROPICS AND DOWNSTREAM ACROSS THE EAST CENTRAL PACIFIC AND
US MAINLAND---BEYOND DAY 5 (WEDNESDAY).

THE SYSTEM---MIGRATING ACROSS THE DATELINE ON SUNDAY AND REACHING
155W NEXT WEDNESDAY---REMAINS `ON TRACK`---WITH THE DETERMINISTIC
ECMWF A MORE AGGRESSIVE FORECAST APPROACH VERSUS THE GFS---BECAUSE
THE GFS IS FASTER AND WEAKER ALOFT.

AT 500MB (BETWEEN 1/00Z AND 3/00Z), THIS TRANSLATES TO 10 DEGREES
OF SEPARATION (LONGITUDE) ALONG 40N LATITUDE BETWEEN THE 26/00Z
GFS DETERMINISTIC (150W) AND THE 26/00Z DETERMINISTIC ECMWF
(160W). WITH THIS NEXT WEST-TO-EAST MOVING MID-LEVEL TROUGH IN THE
PATTERN/SEQUENCE---THE ECMWF AGAIN WOULD BE THE AGGRESSIVE
SOLUTION IN THE SUBTROPICS AND HAWAI`I.

FOR THE DAY 5-7...RECOMMEND A BLEND OF THE LAST 2 ECENS MASS FIELD
FORECASTS---THE 25/12Z AND 26/00Z CYCLES. PRIOR TO DAY 5...THE
26/00Z DETERMINISTIC APPEARED TO HAVE UTILITY IN HANDLING THE
SMALLER-SCALE DETAILS AND THE REGIONAL SENSIBLE WEATHER PATTERN IN
AND AROUND HAWAI`I.

VOJTESAK

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