Prognostic Meteorological Discussion
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000
FXHW01 KWNH 291207
PMDHI

HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
804 AM EDT SAT AUG 29 2015

VALID 00Z SUN AUG 30 2015 - 00Z SUN SEP 06 2015

THE 29/00Z GFS/ECMWF AND THEIR ENSEMBLES ARE IN GOOD ALIGNMENT
WITH THE SYNOPTIC-SCALE PATTERN---PRIMARY SENSIBLE WEATHER
FEATURES THROUGH 132 HOURS (3/12Z)---AND THE CURRENT HAWAI`I
FORECASTS.

MID-LATITUDE PACIFIC HAS BECOME HIGHLY-AMPLIFIED ALONG 130W AND
THE DATELINE WITH A SPRAWLING DEEP-LAYERED RIDGE CENTERED INVOF
40N 160W.

THE ONE REGION OF THE PACIFIC---IN THE CURRENT PATTERN--- THAT
WARRANTS SOME MENTION IS INVOF 30N 170W. THIS REGION OF THE
PACIFIC IS A SHORT-TERM `SPAWNING GROUND` FOR SHALLOW CUTOFF LOWS.
THE NEGATIVE-TILT TROUGH AND BLOCKY UPSTREAM PATTERN IS ASSOCIATED
WITH THE REMNANT CIRCULATION FORMERLY KNOWN AS `ATSANI`. THIS
CIRCULATION WHISKED `LOKE` DOWNSTREAM A COUPLE OF DAYS AGO...AND
HAS GENERATED A CUTOFF LOW NEAR 26N 165W (ON CURRENT SATELLITE).

IT`S AN UNUSUAL PATTERN TO SAY THE LEAST---AND THE CUTOFF PROVIDES
ADDITIONAL CONCERN FROM A DYNAMICAL SHEAR PERSPECTIVE.

THIS 29/00Z DETERMINISTIC RUN, THE GFS/ECMWF HAVE THE CUTOFF ON AN
INTRIGUING `PATH` THAT FILLS THE REGION CURRENTLY SERVING AS THE
`COL` PROVIDING SEPARATION BETWEEN `KILO` AND `IGNACIO`. THE MEANS
DO NOT NECESSARILY ACCOUNT FOR THE WELL-CONSTRUCTED FEATURE IN THE
`BIG-PICTURE` LONGER-RANGE SOLUTION --- GIVEN THE PRESENCE OF THE
DEEP-LAYERED RIDGE. AND,

WITH THE GLOBAL GUIDANCE MAINTAINING THE DEEP-LAYERED RIDGE
CONFIGURATION, ITS GRADUAL SHIFT ---SLIGHTLY SOUTH OF DUE
EAST---THROUGH THE END OF THIS FORECAST PERIOD (CLOSER TO A
LAT/LONG POSITION NEAR 150W)---THE INTERACTION BETWEEN THE CUTOFF,
`KILO` AND `IGNACIO` DO NOT SEEM TO ALTER THE
OVERALL---SYNOPTIC-SCALE PROGRESSION OF THIS PARTICULAR TRIO OF
TROPICALS FOR THE DAY 4-7 PERIOD.

VOJTESAK



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