Area Forecast Discussion
Issued by NWS Fairbanks, AK

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
000
FXAK69 PAFG 061121
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
321 AM AKDT WED MAY 6 2015

.DISCUSSION...

MODELS...GOOD RUN TO RUN CONTINUITY CONTINUES. INITIALIZED WELL
AGAINST THE 06Z SURFACE ANALYSIS. POSITIONS OF MAJOR FEATURES
WERE ALMOST SPOT ON AND HEIGHTS WERE WITHIN A COUPLE MB. MODELS
ARE MORE AGGRESSIVE IN BRINGING A LOW NORTH INTO THE KUSKOKWIM
VALLEY AND UP THE WEST COAST TONIGHT AND FRIDAY. PRECIPITATION
COVERAGE LOOKS A BIT UNDERDONE ON THE NAM SO WILL LEAN ON THE
GFS...ECMWF AND SREF FOR COVERAGE AND PROBABILITIES. WILL USE A
BLEND OF GFS AND ECMWF FOR PRECIPITATION AMOUNTS. FOR REMAINDER
OF THE FORECAST WILL USE A BLEND OF MODELS OUTPUT TO NUDGE THE
CURRENT FORECAST DATABASE.

ALOFT...AT 500 HPA...RIDGE WILL CONTINUE TO ROTATE OVER MAINLAND
ALASKA TODAY AND WILL LIE OVER THE ALCAN BORDER BY THURSDAY
MORNING WITH A RIDGE EXTENDING WEST OVER NORTON SOUND. A SHORTWAVE
OVER EASTERN SIBERIA WILL BOUNCE OVER THE TOP OF THE RIDGE
WEDNESDAY NIGHT INTO THURSDAY. TROUGH WILL DIG SOUTH OVER THE
EASTERN BERING SEA AT THE SAME TIME. THE RIDGE WILL SLOWLY BE
PUSHED INTO CANADA AS THE TROUGH MOVES EAST OVER THE WEST COAST
LATE THURSDAY NIGHT AND MERGES WITH A 534 DAM LOW OVER THE ALASKA
PENINSULA. THE LOW OVER THE PENINSULA THEN DROPS INTO THE SOUTHERN
GULF OF ALASKA FRIDAY BEFORE MOVING OVER THE NORTHERN GULF OF
ALASKA AND STRENGTHENING TO 530 DAM EARLY SATURDAY MORNING.
RIDGING WILL PERSIST OVER THE CENTRAL AND EASTERN INTERIOR. AT 850
HPA...TEMPERATURES RISE TO AROUND 2 ABOVE CELSIUS IN THE INTERIOR
TODAY...THEN TO AROUND 5 ABOVE SATURDAY BEFORE COOPING BACK DOWN
TO AROUND ZERO CELSIUS ON SUNDAY. THE LOWER YUKON DELTA WILL SEE
TEMPERATURES WARM TO AROUND ZERO BY FRIDAY MORNING THEN COOL BACK
DOWN TO NEAR 5 BELOW. OVER THE NORTHWEST COAST TEMPERATURES WILL
REMAIN STEADY AROUND 5 BELOW CELSIUS.

SURFACE...THERMAL TROUGH WILL PERSIST NORTH OF THE ALASKA RANGE.
THE RIDGE TO THE SOUTH WILL STRENGTHEN A BIT AND GAP FLOW WINDS
WILL DEVELOP TODAY AND CONTINUE INTO THURSDAY. THE BIG PLAYER WILL
BE THE LOW THAT DEVELOPS OVER THE ALASKA PENINSULA AND MOVES TO
THE KUSKOKWIM DELTA TONIGHT...THEN CONTINUES NORTH SPREADING
CLOUDS AND PRECIPITATION OVER THE WESTERN INTERIOR AND COAST.
THIS WILL DAMPEN THE THERMAL TROUGH A BIT AND HELP INJECT SOME
MOISTURE INTO THE WESTERN AND MAYBE EVEN THE CENTRAL INTERIOR.
WEAK HIGH PRESSURE OVER THE ARCTIC COASTAL WATERS WILL MOVE
NORTHEAST AS A 1026 MB CENTER DEVELOPS OVER THE EASTERN BEAUFORT
SEA AND MOVES TO THE CANADIAN ARCHIPELAGO BY THURSDAY MORNING. A
WEAK TROUGH WILL DEVELOP OVER THE COAST AS THE RIDGE MOVES OUT.

ARCTIC COAST AND BROOKS RANGE...STILL A LOT OF STRATUS OVER THE
AREA. DO NOT EXPECT MUCH CHANGE AS LOW STRATUS WILL CONTINUE TO
HANG AROUND. MAY SEE SOME IMPROVEMENT AS THE STRATUS LIFTS A
LITTLE...BUT AT BEST ONLY EXPECT CEILINGS TO LIFT TO AROUND 2000
FEET. A FEW FLURRIES WILL BE POSSIBLE...ESPECIALLY FROM BARROW
WEST AS THE SHORTWAVE ALOFT PUSHES OVER THE TOP OF THE RIDGE
TONIGHT INTO THURSDAY MORNING. PATCHY FOG MAY ALSO BE AN ISSUE AS
IT MAY BE PRETTY DENSE FOR A FEW HOURS OVERNIGHT. UNFORTUNATELY
WHEN AND WHERE WILL BE VERY DIFFICULT TO FORECAST...BUT IT LOOKS
LIKE A GOOD CHANCE OF DENSE FOG FRIDAY MORNING. EAST WINDS OVER
MOST OF THE AREA AT 10 TO 20 MPH TODAY. WINDS WILL DIMINISH TO 5
TO 15 MPH THURSDAY.

WEST COAST AND WESTERN INTERIOR...A FEW SHOWERS OVER THE LOWER
YUKON DELTA THIS EVENING...THEN THE LOW MOVES NORTH TO THE
KUSKOKWIM DELTA AND THAT WILL BRING A GOOD ROUND OF SHOWERS TO
THE AREAS AS THEY MOVE SOUTH TO NORTH BEGINNING EARLY THURSDAY
MORNING AND CONTINUING THROUGH LATE FRIDAY. SOME CLEARING OVER
THE LOWER YUKON DELTA AND ADJACENT COASTAL AREAS BEGINNING FRIDAY
MORNING. LOW STRATUS CEILINGS WILL PERSIST OVER THE EASTERN
BERING SEA AND BERING STRAIT. PRECIPITATION WILL BE MOSTLY RAIN
SOUTH OF KOTZEBUE WITH A MIX OF RAIN AND SNOW FROM KOTZEBUE NORTH.
WINDS GENERALLY 5 TO 15 MPH...THE EXCEPTION WILL BE THE BERING
STRAIT AND ST LAWRENCE ISLAND WHERE WINDS WILL BE 15 TO 30 MPH
THIS MORNING DIMINISHING TO 10 TO 20 MPH THIS AFTERNOON. GOES IFR
PROBABILITY PRODUCT AT 06/0900Z INDICATES A LARGE AREA OF LOW
STRATUS AND POSSIBLY FOG OVER ST LAWRENCE ISLAND AND THE BERING
STRAIT.

CENTRAL AND EASTERN INTERIOR...MOSTLY SUNNY TODAY. CONDITIONS
WILL BE DRIER TODAY SO NOT EXPECTING MUCH IN THE WAY OF LOW LEVEL
CONVECTION OR CLOUDS TODAY. WARMER CONDITIONS TODAY THAN YESTERDAY
AS WE GET BETTER SOLAR HEATING. MANY AREAS WILL SEE TEMPERATURES
RISE TO THE MID 50 TO MID 60S. GAP FLOW WINDS DEVELOPING NEAR THE
ALASKA RANGE TODAY...EXPECT WINDS FROM DELTA JUNCTION SOUTH AND
NEAR ALASKA RANGE PASSES TO INCREASE TO 20 TO 35 MPH. WIND WILL
DIMINISH FRIDAY MORNING. REMAINDER OF THE AREA WILL HAVE WINDS
GENERALLY LESS THAN 15 MPH.

EXTENDED FORECAST FOR DAYS 5 TO 8...LONG WAVE TROUGH MOVING EAST
INTO CANADA AND WEAK RIDGING ALOFT BUILDING OVER THE INTERIOR.
THERMAL TROUGH OVER THE INTERIOR WITH DRY CONDITIONS CONTINUING
INTO AT LEAST THE MIDDLE OF NEXT WEEK. SOUTH FLOW UP THE WEST
COAST WILL BRING PERIODS OF SHOWERS OVER THE AREA. ALONG THE
ARCTIC COAST EXPECT STRATUS TO PERSIST AS RIDGE BUILDS OVER THE
ARCTIC AND WEAK ONSHORE OR EASTERLY FLOW CONTINUES.

&&

.FIRE WEATHER...FOR THE INTERIOR RED FLAG WARNINGS HAVE BEEN
ISSUED IN ZONES 223 225 AND 226 FOR TODAY AND WILL MOST LIKELY BE
CONTINUED INTO THURSDAY. MOST INTERIOR AREAS HAD RELATIVE
HUMIDITY VALUES IN THE 20 TO 30 PERCENT RANGE YESTERDAY AND THOSE
VALUES SHOULD BE LOWER TODAY. GAP WINDS KICKING UP IN THE
AFTERNOON TO 20 TO 35 MPH WILL PERSIST INTO THURSDAY EVENING.
OVERNIGHT RELATIVE HUMIDITY RECOVERY WILL BE POOR TO FAIR THROUGH
FRIDAY. IN THE WESTERN ZONES...RELATIVE HUMIDITY VALUES WILL BE
AROUND 30 PERCENT SO NEAR RED FLAG CONDITIONS WILL BE POSSIBLE IN
ZONE 227 NEAR THE ALASKA RANGE AS WINDS GUST UP TO AROUND 30 MPH.
RAIN MOVING INTO THE AREA TONIGHT WILL PUSH RELATIVE HUMIDITY
VALUES UP ABOVE 30 PERCENT FOR THE REMAINDER OF THE WEEK.

&&

.HYDROLOGY...LOTS OF REPORTS OF ICE MELTING PRETTY SIGNIFICANTLY
IN PLACE WITH LOTS OF WATER ON TOP OF THE ICE. MOVEMENT OF THE
ICE REPORTED FROM SEVERAL LOCATIONS ALONG THE YUKON RIVER BUT NO
SIGNIFICANT MOVEMENT. ALSO A FEW REPORTS OF SIGNIFICANT OPEN
STRETCHES OF WATER IN THE YUKON RIVER. REPORTS FROM OBSERVERS AND
SPOTTERS CONTINUE TO INDICATE THAT WATER LEVELS ARE BELOW NORMAL.
RIVER WATCH MISSION WILL BE OVER THE UPPER YUKON BETWEEN THE
YUKON RIVER BRIDGE AND EAGLE.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

FIRE WEATHER WATCH FOR AKZ223-AKZ225-AKZ226.

RED FLAG WARNING FOR AKZ223-AKZ225-AKZ226.

&&

$$

SDB MAY 15


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.