Prognostic Meteorological Discussion
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FXAK02 KWNH 241836
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ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
235 PM EDT SUN JUL 24 2016

VALID 12Z THU JUL 28 2016 - 12Z MON AUG 01 2016

...HEAVY RAIN POTENTIAL FOR SRN/SERN AK THEN WRN AK AND THE
INTERIOR...

...GUIDANCE ASSESSMENT AND WEATHER HIGHLIGHTS/THREATS...

TODAYS WPC MEDIUM RANGE PRODUCT SUITE WAS AGAIN PRIMARILY DERIVED
FROM A BLEND OF THE REASONABLY COMPATABLE 12 UTC GFS AND 00/12 UTC
ECMWF ALONG WITH THE 00 UTC NAEFS/ECMWF ENSEMBLES DAY4/THU BEFORE
QUICKLY TRANSITIONING DAY5/FRI TO JUST THESE ENSEMBLE MEANS
THEREAFTER CONSISTENT WITH INCREASING FORECAST SPREAD. THIS
SOLUTION MAINTAINS GOOD WPC CONTINUITY.

AN AMPLIFIED CLOSED LOW/TROUGH IS EXPECTED TO TRACK NEWD OVER THE
GULF OF AK THU. THIS WILL SUPPORT SIGNIFICANT LOWER ATMOSPHERIC
LOW/FRONTAL DEVELOPMENT TO PROVIDE FOCUS FOR HEAVY WIND/WAVES AND
LEAD/WRAPPED HEAVY RAINFALL WITH MAX POTENTIAL INLAND INTO FAVORED
COASTAL TERRAIN OF SRN/SERN AK AS FUELED BY A PRECIPITATBLE WATER
PLUME UPWARDS TO 1-1.25". THE SUBSEQUENT SRN TIER SYSTEM ENERGY
PATTERN IN THE WAKE OF THIS LOW SEEMS LESS AMPLIFIED/ORGANIZED IN
MORE PROGRESSIVE FLOW UNDERNEATH AN INCREASINGLY DOMINANT ARCTIC
TO WRN/NRN AK MID-UPPER LEVEL TROUGH. THIS AMPLIFYING NRN STREAM
SYSTEM WILL SUPPORT AN ANOMOLOUSLY WELL DEFINED MID-SUMMER FRONTAL
PASSAGE GRADUALLY ACROSS THE INTERIOR. THIS MAY LEAD TO SOME
POTENTIALLY HEAVY CONVECTION/RAINFALL AS FUELED BY DYNAMICS ALOFT
AND FAVORABLE SWRLY INFLOW AS PER A PLUME OF 1"+ PRECIPIATBLE
WATER VALUES FROM THE BERING SEA IN ADDITION TO WIDESPREAD
UNSETTLED WEATHER/POST-FRONTAL COOLING WED THROUGH NEXT WEEKEND.
ACTIVITY MAY ALSO SPREAD ACROSS SWRN AK INTO THE NRN GULF OF AK
AND SRN AK INTO EARLY NEXT WEEK WITH CONTINUED FLOW AMPLIFICATION
POTENTIAL.

SCHICHTEL

$$




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