Prognostic Meteorological Discussion
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FXAK02 KWNH 301805
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ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
204 PM EDT SAT JUL 30 2016

VALID 12Z WED AUG 03 2016 - 12Z SUN AUG 07 2016

...GUIDANCE/UNCERTAINTY ASSESSMENT...

THE WPC ALASKAN MEDIUM RANGE PRODUCT SUITE MAINTAINS CLOSE WPC
CONTINUITY AS PRIMARILY DERIVED FROM A COMPOSITE BLEND OF
REASONABLY WELL CLUSTERED GUDIANCE FROM THE 12 UTC GFS/00 UTC
ECMWF AND THE GEFS/NAEFS/ECMWF ENSEMBLE MEANS DAYS 4-6 WED-FRI IN
A PERIOD WITH SEEMINGLY AVERAGE OR BETTER PREDICTABILITY. SPREAD
INCREASES RAPIDLY BY NEXT WEEKEND SO OPTED FOR JUST AN ENSEMBLE
MEAN BLEND AMID GROWING UNCERTAINTY.

...PATTERN AND WEATHER HIGHLIGHTS/THREATS...

THE CONTINUED STEADY PASSAGE OF AN AMPLIFIED MID-UPPER LEVEL
LOW/TROUGH SPLIT OVER THE GULF OF AK WED AND THU WILL SUPPORT
COMPACT SURFACE LOW/FRONTAL SYSTEM AND MOISTURE ENHANCEMENT. THIS
WILL FUEL HEAVIER RAINS WRAPPED INTO SRN AND ESPECIALLY SERN AK
THIS PERIOD AS ENHANCED BY FAVORED COASTAL TERRAIN.
MEANWHILE...ENERGETIC NRN STREAM ARCTIC TROUGHING ALOFT SHOULD
SUPPORT ORGANIZED BUT MODEST TRAILING SURFACE FRONTAL
PRECIPITATION PASSAGE/COOLING INLAND DOWN ACROSS WRN/N-CENTRAL AK
AND NRN BERING SEA MID-LATE NEXT WEEK. LATER...GUIDANCE STILL
SHOWS SIGNALS FOR APPROACH INTO THE BERING SEA/ALEUTIANS THEN
SW/WRN AK OF ERN ASIAN ENERGY THAT WOULD FAVOR LEAD SYSTEM
EFFECTS/PCPN OVER THE REGION LATE WEEK/NEXT WEEKEND IN ADVANCE OF
DEEPER SURFACE SYSTEM POTENTIAL MOVING IN UPSTREAM NEXT WEEKEND.

SCHICHTEL

$$





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