Small Craft Advisory 4, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
1244 PM AKDT SUN MAY 4 2014

.DISCUSSION...

MODELS...GOOD RUN TO RUN CONTINUITY. SURFACE LOW OVER THE
NORTHWEST COAST INITIALIZED ABOUT 5MB HIGHER THAN MODELS. THE
MODELS REMAIN IN GOOD AGREEMENT OUT TO AROUND 90 HOURS BEFORE
DIVERGING. WILL LEAN ON A BLEND OF ECMWF...NAM AND GFS FOR POPS
AND QPF.

ALOFT...AT 500 HPA...RIDGE OVER EASTERN HALF OF THE STATE IS
SLIDING EAST AS 514 DAM CLOSED LOW OVER THE NORTHWEST COAST
CONTINUES TO DEEPEN AND MOVE NORTH NORTHEAST. THE LOW WILL MOVE
BE 250 NM NORTH OF BARROW BY EARLY MONDAY MORNING...AND 500 NM
NORTH OF BARROW BY MONDAY AFTERNOON AS HEIGHTS FALL TO 500 DAM.
THE ASSOCIATED TROUGH WILL EXTENDS FROM OVER POINT LAY TO TO
DEERING TO NOME AND SOUTHWEST TODAY...TO OVER WAINWRIGHT TO
SELAWIK TO KOYUK TO TOKSOOK BAY AND SOUTHWEST TONIGHT...THEN FROM
KAKTOVIK TO BETTLES TO ANIAK AND SOUTHWEST BY MONDAY AFTERNOON.
THE RIDGE WILL BE PUSHED DOWN A BIT AS THE TROUGH MOVES EAST AND
THEN BEGINS TO RIDE OVER IT. HEIGHTS OVER THE INTERIOR WILL FALL
FROM AROUND 560 DAM TODAY TO 544 DAM BY MONDAY AFTERNOON. A 534
DAM CLOSED LOW IN THE NORTHWEST PACIFIC WILL HELP TO DAMPEN THE
RIDGE AS IT MOVES NORTHEAST FROM 44N 166W TO NEAR 53N 157W BY
TUESDAY AFTERNOON. AT 850 HPA...TEMPERATURES ABOUT 6 DEGREES
CELSIUS COLDER TODAY OVER FAIRBANKS THAN ON SATURDAY...THAT TREND
WILL CONTINUE AS COLD AIR ADVECTION PUSHES TEMPERATURES DOWN TO
AROUND 1 BELOW ZERO CELSIUS BY MONDAY AFTERNOON. THE MODELS ARE
UNCERTAIN AS TO WHAT HAPPENS AFTER THAT AS THE ZERO ISOTHERM
WOBBLES AROUND OVER FAIRBANKS AND THE INTERIOR THE NEXT FEW DAYS.
A STRONGER BLAST OF COLD AIR WILL SWEEP OVER THE NORTHWEST COAST
PUSHING THE 10 BELOW CELSIUS ISOTHERM AS FAR SOUTH AS NORTON SOUND
AND EAST TO BARTER ISLAND BEFORE IT SLIDES BACK NORTH.

SURFACE...LOW JUST NORTH OF BARROW INITIALIZED AT 15Z AT 1005MB.
WEAK COLD FRONT LIES FROM NEAR BARROW TO MANLEY HOT SPRINGS TO
COOK INLET TODAY AND WILL CONTINUE TO WEAKEN AS IT MOVES TO LIE
FROM MCKENZIE BAY TO CHICKEN AND SOUTHWEST BY EARLY MONDAY
MORNING. LOW WILL CONTINUE NORTH TO 76N 160W BY MONDAY AFTERNOON
THEN CONTINUE NORTHEAST. ASSOCIATED COLD FRONT IS SPREADING A
MIXTURE OF SHOWERS OVER THE WEST COAST AS FAR EAST AS THE MIDDLE
YUKON VALLEY AND SOUTH TO NORTON SOUND. SOME OF THE CLOUDS ARE
WORKING INTO THE HIGH PRESSURE BUT NOT EXPECTING MUCH
PRECIPITATION EAST OF THE YUKON AS THE FRONT DECAYS AS IT MOVES
INTO THE DRY AIR. THERMAL TROUGH STRENGTHENS OVER THE UPPER
TANANA VALLEY TODAY AND REMAINS OVER THE AREA INTO MID WEEK.

ARCTIC COAST...SATELLITE NOT MUCH HELP TODAY. OBSERVATIONS KEEP
BOUNCING AROUND BUT LOOKS LIKE THE WORST HAS NOT MADE IT TO THE
NORTHWEST COAST YET. EXPECT THAT TO OCCUR THIS EVENING.
CONDITIONS EAST OF BARROW WILL BE MUCH DIFFERENT THAN FROM BARROW
WEST AS THE LOW MOVES NEARLY STRAIGHT NORTH TONIGHT AND THE
COLDEST AIR REMAIN WEST OF DEADHORSE. PRECIPITATION WILL ALSO STAY
MAINLY WEST OF NUIQSUT. NEAR BLIZZARD CONDITIONS THIS EVENING FROM
BARROW WEST WITH STRONG WINDS GENERATED BY COLD AIR ADVECTION AND
THE TIGHT GRADIENT NEAR THE LOW. A COUPLE INCHES OF SNOW POSSIBLE
FROM BARROW WEST BUT HARD TO VERIFY SINCE IT WILL BE BLOWING
AROUND PRETTY GOOD. WILL CONTINUE THE ADVISORIES FOR Z201 AND
Z202.

WEST COAST AND WESTERN INTERIOR...FRONT SHOWS UP PRETTY GOOD ON
VISIBLE SATELLITE AT 19Z. LEADING EDGE OF FRONT APPEARS TO BE
NEAR BETTLES TO MCGRATH. SNOW SHOWERS BEING REPORTED FROM NORTON
SOUTH NORTH. EXPECT THAT THAT WILL CONTINUE INTO THE EVENING THEN
DISSIPATE FROM SOUTH TO NORTH THROUGH THE NIGHT. WITH SOME
LINGERING SHOWERS ALONG THE SOUTH SLOPES OF THE BROOKS RANGE. WITH
GOOD COLD AIR ADVECTION EXPECT TEMPERATURES TO BE 15 TO 20 DEGREES
COOLER THAN THE LAST WEEK. WINDS WEST TO NORTHWEST THIS EVENING
TAPERING OFF BY MORNING FOR AREAS SOUTH OF KIVALINA TO LESS THAN
10 MPH. FROM KIVALINA NORTH WINDS WEST WINDS TO 25 MPH WILL TAPER
TO SOUTHWEST AT 10 TO 15 MPH BY MONDAY MORNING.

CENTRAL AND EASTERN INTERIOR...SOME WEAK LOW TOP SHOWERS OVER THE
FORTYMILE COUNTRY THIS EVENING WITH DECAYING FRONTAL SYSTEM
MOVING OVER THE AREA AND INTERACTION WITH THE THERMAL TROUGH.
GENERALLY STABLE ATMOSPHERE WILL CONTINUE WITH NO THUNDERSTORM
ACTIVITY INTO MID WEEK. TEMPERATURES 15 TO 20 DEGREES COOLER THIS
WEEK THAN LAST. WINDS GENERALLY LESS THAN 10 MPH.

&&

.FIRE WEATHER...SOME CONVECTIVE POTENTIAL OVER THE FORTYMILE
COUNTRY THIS AFTERNOON...BUT LOOKS TO BE LOW TOP STUFF WITHOUT ANY
LIGHTNING. RELATIVE HUMIDITY VALUES WILL BE HIGHER THE NEXT
SEVERAL DAYS AS DEWPOINTS HAVE RISEN 3 TO 5 DEGREES AND COOLER
TEMPERATURES WILL PREVAIL. WEDNESDAY LOOKS TO BE THE NEXT DAY FOR
POTENTIAL THUNDERSTORM ACTIVITY

&&

.HYDROLOGY...PRETTY QUIET BREAKUP WISE IN THE INTERIOR AND EXPECT
IT TO REMAIN THAT WAY AS FREEZING LEVELS FALL AND SLOW DOWN THE
MELTING PROCESS AT HIGHER ELEVATIONS.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FOR AKZ201-AKZ202.

SMALL CRAFT ADVISORY FOR PKZ210.

GALE WARNING FOR PKZ230-PKZ235.

BRISK WIND ADVISORY FOR PKZ225-PKZ240-PKZ245.
&&

SDB MAY 14