Prognostic Meteorological Discussion
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FXAK02 KWNH 051807
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
206 PM EDT SUN JUL 05 2015

VALID 12Z THU JUL 09 2015 - 12Z MON JUL 13 2015

...PATTERN HIGHLIGHTS AND GUIDANCE/UNCERTAINTY ASSESSMENTS...

TODAYS WPC ALASKAN MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500
MB PROGS ALONG WITH ASSOCIATED SENSIBLE WEATHER GRIDS ARE
PRIMARILY DERIVED FROM A COMPOSITE BLEND OF THE HIGHLY COMPATABLE
06 UTC GEFS MEAN AND 00 UTC NAEFS/ECMWF ENSEMBLE MEANS. THESE
OFFER GOOD CONTINUITY. HOWEVER...OPTED TO ALSO INCLUDE SOME INPUT
AND USED MANUAL ADJUSTMENTS TO INCORPORATE MORE DETAILED
DETERMINISTIC GUIDANCE OF THE 12 UTC GFS AND 00 UTC ECMWF DAYS
4-8. THESE MODELS HAVE CONVERGED UPON A MORE COMMON SOLUTION
COMPARED TO YESTERDAY...BOLSTERING FORECAST CONFIDENCE SOME.

THE OVERALL PATTERN EVOLUTION OFFERS ABOVE AVERAGE PREDICTABILITY
AND FEATURES A SLOWLY EASTWARD TRANSLATING CLOSED BERING SEA MEAN
LOW. LESS CERTAIN EJECTING IMPULSES AND ATTENDANT SURFACE
LOWS/WIDESPREAD DAILY PCPN POTENTIAL INCREASINGLY WORK OVER TIME
DOWNSTREAM AND INLAND THROUGH SW/SRN ALASKA INTO THE INTERIOR AND
ALSO THE GULF OF AK. THIS OCCURS AS AN AMPLIFIED LEAD MID-UPPER
LEVEL RIDGE GRUDGINGLY WEAKENS AND SHIFTS FOCUS OVERTOP...ALSO IN
CONJUCTURE WITH PASSAGE OF A MORE DEFINED YET UNCERTAIN ARCTIC SEA
LOW OFF THE NORTH SLOPE MID-LATE WEEK.

SCHICHTEL

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