436  
FXHW01 KWNH 201223  
PMDHI  
 
HAWAII EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
722 AM EST TUE FEB 20 2018  
 
VALID 00Z WED FEB 21 2018 - 00Z WED FEB 28 2018  
 
UPPER LOW TO THE NORTH OF THE REGION WILL CONTINUE TO LIFT  
NORTHWARD AND WEAKEN, ALLOWING DRIER AIR TO REMAIN OVER HAWAI'I.  
PRECIPITABLE WATER VALUES WILL GENERALLY BE UNDER 1.25 INCHES  
THROUGH WEDNESDAY. BY THURSDAY, ANOTHER UPPER LOW IS FORECAST TO  
FORM TO THE NORTHWEST OF THE AREA (AROUND 30N/170W OR OVER THE  
PAPHANAUMOKUAKEA MARINE NATIONAL MONUMENT) WITH A DOWNSTREAM  
NARROW RIDGE ALONG 150W. THIS WILL ALLOW DEEP TROPICAL MOISTURE TO  
SURGE NORTHWARD ACROSS THE STATE WITH LOCALLY MODERATE TO HEAVY  
RAIN AND EMBEDDED THUNDERSTORMS. PRECIPITABLE WATER VALUES ARE  
FORECAST TO RISE TO BETWEEN ABOUT 1 1/3 TO 1 3/4 INCHES THROUGH  
THE PERIOD (NEXT TUESDAY) WHICH IS WELL ABOVE AVERAGE FOR LATE  
FEBRUARY. ENSEMBLES INDICATE A RELOADING OF THE UPPER LOW NEAR OR  
JUST WEST OF THE SAME LOCATION NEXT WEEK WHICH MAY PULL THE  
PRECIPITABLE WATER AXIS WESTWARD NEXT WEEK, PERHAPS WEST OF  
KAUAI/NI'IHAU. LATEST 06Z GFS AND 00Z ECMWF GENERALLY FALL IN LINE  
WITHIN THE ENSEMBLE SPREAD, AND A BLEND OF THESE SOLUTIONS SHOULD  
SUFFICE, THOUGH THEIR QPF DIFFERENCES ARE MUCH LARGER THAN THEIR  
500MB OR SURFACE PATTERNS.  
 
FRACASSO  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page