THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD


ALASKA EXTENDED FORECAST DISCUSSION




ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
255 PM EDT THU MAR 26 2015

VALID 12Z MON MAR 30 2015 - 12Z FRI APR 03 2015

WPC LATEST ALASKAN MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500
MB PROGS HAVE BEEN PRIMARILY DERIVED FROM A BLEND OF THE 00 UTC
GFS/ECMWF AND ECMWF ENSEMBLE MEAN DAYS 4/5 MONDAY/TUESDAY.
FORECAST SPREAD AND EMBEDDED SYSTEM UNCERTAINTY GROWS RAPIDLY
THEREAFTER LEADING TO PREFERENCE FOR HEAVIER EMPHASIS ON THE ECMWF
ENSEMBLE MEAN INTO DAYS 6-8 THAT HAS BETTER COMPATABILITY WITH THE
MORE VARIED SMALL TO MID SCALE DETAILS FROM GFS/ECMWF
DETERMINISTIC MODELS. THIS OVERALL FORECAST STRATEGY MAINTIANS
GOOD WPC CONTINUITY THROUGH THESE LONGER TIME FRAMES.

THIS OVERALL SOLUTION WAS ALSO DETERMINED AFTER PATTERN
CONSIDERATION AND AS PER COLLABORATION WITH THE LOCAL NATIONAL
WEATHER SERVICE EXPERTS FROM THE FAIRBANKS...ANCHORAGE...AND
JUNEAU WFO OFFICES. FAIRBANKS SUPPORTED MORE AMPLIFIED MEAN
MID-UPPER LEVEL TROUGHING TRENDS OVER NWRN ALASKA COMPARED TO
YESTERDAY. THIS OFFERS SOME ADDITIONAL COOLING AND LIGHT-SIDE
PCPN. ANCHORAGE SUGGESTED GUIDANCE THAT BLENDED WELL FROM THE DAY
3 00 UTC ECMWF LOW OVER THE GULF OF AK...THEN PROBABLY MOST IN
LINE WITH THE GFS/ECMWF AND ENSEMBLES FOR MEDIUM RANGE TIME SCALES
UPSTREAM NEAR THE ALEUTIANS AND THE GULF OF AK WHERE THE LOWS WERE
LESS PREDICTABLE. ORGANIZED LOW DEVELOPMENT OVER THIS PERIOD OFFER
MODEST PCPN POTENTIAL OVER THE ALEUTIANS AND FROM SRN TO SERN
ALASKA. JUNEAU WAS FINE WITH THAT THOUGHT PROCESS/SCENARIO FOR
THEIR FORECAST AREA OF RESPONSIBILITY.

SCHICHTEL





Last Updated: 255 PM EDT THU MAR 26 2015