THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD


ALASKA EXTENDED FORECAST DISCUSSION




ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
252 PM EDT SAT SEP 20 2014

VALID 12Z WED SEP 24 2014 - 12Z SUN SEP 28 2014

NORTHERN PACIFIC AND ARCTIC REGION SHOULD SEE A PATTERN SHIFT IN
THE MEDIUM RANGE PERIOD. INITIAL TROUGHING IN THE BERING SEA
SHOULD BE REPLACED BY RIDGING AS NORTHERN STREAM ENERGY MOVING
ACROSS EASTERN RUSSIA FORCES TROUGHING WEST OF 170E. TROUGHING
SOUTH OF THE PANHANDLE MIDWEEK SHOULD RETROGRADE DUE TO THE ENERGY
MOVING OUT OF THE BERING SEA. THE MODELS/ENSEMBLES CONTINUE TO
STRUGGLE WITH THE MULTIPLE ENERGY SOURCES AND EVOLUTION THEREOF...
THOUGH AT LEAST SHOW SOME CLUSTERING AT THE START OF THE PERIOD.
THE 12Z GFS AND 00Z ECMWF ARE CLOSE ENOUGH TO USE A BLEND BETWEEN
THE TWO ON WED/D4... MAINTAINING THE DEFINITION OF THE RATHER
STRONG SYSTEM SOUTH OF THE PANHANDLE. THEREAFTER... THAT SFC LOW
SHOULD DRIFT NORTH NORTHWESTWARD INTO THE GULF AS ANOTHER SYSTEM
IN THE NORTH PACIFIC PUSHES EASTWARD. THAT SHOULD LIKELY END OF IN
THE GULF BY NEXT WEEKEND BUT THERE HAS BEEN LITTLE CONSISTENCY IN
TIMING/LOCATION. AN ENSEMBLE MEAN BLEND WAS IMPLORED FOR THE DAYS
6-8.

IN THE NORTH... CONSENSUS OF THE MODELS WAS FOR A QUICKER BUT
STRONGER SHORTWAVE AND ASSOCIATED SFC FRONT TO CROSS THE NORTH
SLOPE AND INTERIOR... BUT LOSING SUPPORT AS IT PUSHES EAST BY
FRI/D6. TEMPERATURES SHOULD BE NEAR TO BELOW AVERAGE... WITH 850
TEMP ANOMALIES IN THE -1 TO -2 RANGE PER THE EC ENSEMBLES.
PRECIPITATION SHOULD MOSTLY FOCUS ALONG THE PANHANDLE...
ESPECIALLY AS THE FLOW TURNS MORE ONSHORE... BUT ALSO NORTH OF 65N
WITH THE SHORT WAVE PASSAGE.


FRACASSO





Last Updated: 252 PM EDT SAT SEP 20 2014