000
FXAK69 PAFG 061335
AFDAFG
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
435 AM AKST TUE JAN 6 2009
.DISCUSSION...
THE WEATHER PATTERN WILL GRADUALLY BE UNDERGOING CHANGES DURING THE
SHORT TERM. THE CHANGES IN THE SHORT TERM WILL LEAD TO CHANGES IN
THE MEDIUM RANGE...BUT THE DETAILS BEYOND A FEW DAYS AS STILL
SKETCHY AS RUN TO RUN CONTINUITY HAS BEEN LACKING. DURING THE NEXT
48 TO 60 HOURS THE MODELS ARE IN DECENT AGREEMENT THAT THE COLD
LOW ACROSS THE NORTHEAST GULF AND SOUTHERN YUKON THAT ELONGATES
BACK INTO THE INTERIOR WILL SLOWLY LIFT OUT TOWARD GREAT BEAR LAKE
ON THURSDAY. THIS WILL OCCUR IN RESPONSE TO AN AMPLIFYING RIDGE
ACROSS THE EASTERN PACIFIC AND AHEAD OF AN INCOMING LOW THAT WILL
BE PASSING SOUTH OF THE ALEUTIANS LATE IN THE WEEK.
INTERIOR...THE COLD IS CERTAINLY GOING TO DO IT`S BEST TO HANG ON
IN THE VALLEYS AS LONG AS POSSIBLE. NO CHANGES ARE EXPECTED THE
NEXT FEW DAYS...WITH MOST OF THE VALLEYS HANGING OUT IN THE 40 TO
55 BELOW RANGE THROUGH THURS. AS THE LOW ALOFT EXITS TO THE EAST
ON THURSDAY SOME WEAK RIDGING WILL AT TIMES DEVELOP ACROSS THE
INTERIOR...ALTHOUGH IT MAY GET SQUASHED DOWN SAT BY AN UPPER
TROUGH THAT SWINGS ACROSS THE HIGH ARCTIC. MODELS AND ENSEMBLES
ARE NOW IN MUCH BETTER AGREEMENT THAT THIS HIGH ARCTIC FEATURE
DOES NOT DIVE SOUTH INTO INTERIOR ALASKA. BY THE TIME WE GET TO
THE WEEKEND...BOTH THE GFS AND ECMWF HAVE 850MB TEMPS ABOUT 10C
WARMER THAN THEY ARE AT PRESENT...BUT IT DOES NOT LOOK LIKE THERE
WILL BE A STRONG MECHANISM TO SCOUR THE COLD AIR OUT OF THE
VALLEYS. THERE WILL LIKELY BE SOME SLIGHT MODERATION IN
TEMPS...BUT MOST NOTICEABLE ON THE HILLS. CERTAINLY IF THERE IS A
GOOD MID DECK OF CLOUDS AT SOME POINT OVER THE WEEKEND THAT COULD
ACT TO MODERATE TEMPS A BIT MORE IN THE VALLEYS.
WEST COAST...RELATIVELY QUIET WEATHER FOR THE NEXT FEW DAYS. MAINLY
LIGHT WINDS WITH THE EXCEPTION OF ANY LOCAL DRAINAGE WINDS AND
SOME STRONGER CHANNELED FLOW THROUGH THE BERING STRAIT COAST. THE
PRESSURE GRADIENT INCREASES SOME BY THURS AS THE NEXT PACIFIC LOW
PASSES SOUTH OF THE CENTRAL ALEUTIANS AND A RIDGE REMAINS IN PLACE
ACROSS SIBERIA. THE NEXT CHANCE OF ANYTHING MORE THAN FLURRIES
WILL LIKELY HOLD OFF UNTIL SUNDAY WHEN SOME LIGHT SNOW IS POSSIBLE
SOUTH OF THE SEWARD PENINSULA AS THE PACIFIC LOW RE-DEVELOPS IN
THE NORTHERN GULF AND WEAKENS ACROSS THE SOUTHERN MAINLAND.
NORTH SLOPE...ALSO FAIRLY BENIGN ALONG THE NORTH SLOPE. A WEAK
SURFACE TROUGH MAY PRODUCE SOME FLURRIES OR LIGHT SNOW ALONG PARTS
OF THE COASTAL PLAIN WED-THURS...BUT NO SIGNIFICANT SNOW IS EXPECTED
IN THE FORESEEABLE FUTURE. THE AIRMASS MODERATES A BIT MID-WEEK BUT
THEN ANOTHER SHOT OF COLDER AIR IS EXPECTED ALONG THE BEAUFORT SEA
COAST LATE IN THE WEEK AS AN UPPER LOW ACROSS THE HIGH ARCTIC SLIDES
OFF TOWARD BANKS ISLAND OVER THE WEEKEND.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY FOR AKZ222.
&&
$$
CB JAN 09
