Small Craft Advisory 3, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
209 PM AKDT THU MAY 1 2014

.SYNOPSIS...
ALOFT...
A STRONG 575 DM HIGH AT 500 MB OVER INTERIOR ALASKA WILL PERSIST
THROUGH FRI THEN SLOWLY SLIDE SOUTHEAST AND WEAKEN OVER THE
WEEKEND. WILL SEE WEAK RIDGE OVER SE INTERIOR INTO NEXT WEEK. THIS
WILL CAUSE DRY AND MUCH WARMER THAN NORMAL CONDITIONS OVER MOST OF
NORTHERN ALASKA THROUGH FRI WITH WARM AND DRY CONDITIONS REMAINING
IN THE INTERIOR SAT AND THE SE INTERIOR SUN.

A LOW NEAR MAGADAN WILL MOVE TO THE CHUKOTSK PENINSULA SAT AND TO
NW ALASKA SUN. THIS WILL BRING COLDER TEMPERATURES AND SNOW TO
WESTERN ALASKA SAT AND TO NW ALASKA AND WESTERN INTERIOR SUN.

SURFACE...
A 1004 MB LOW 200 NM NORTHWEST OF WRANGEL ISLAND WILL MOVE NORTH.
A WARM FRONT FROM THIS LOW TO DEMARCATION POINT WILL MOVE NORTH.
A COOL FRONT FROM THIS LOW STRETCHING SOUTH ALONG THE 170W
LONGITUDE LINE WILL ROTATE CLOCKWISE TO A 100 NM N OF BARROW TO
POINT HOPE TO GAMBELL BY 4AM FRI...AND PERSIST THERE UNTIL 4AM
SAT. S WINDS 20-30KT ALONG THE FRONT WILL DECREASE TONIGHT AS THE
LOW MOVES N AND THE GRADIENT WEAKENS. EXPECT A BAND OF RAIN ALONG
THE FRONT TO BECOME MORE SCATTERED SHOWERS SAT AS THE FRONT
WEAKENS.

A WEAK THERMAL TROUGH WILL DEVELOP TONIGHT FROM MCGRATH TO DELTA
JUNCTION AND STRENGTHEN FRI...THEN MOVE TO DELTA TO EAGLE ON SAT
AND PERSIST THERE INTO SUN. NE WINDS 10-15 MPH WITH A FEW GUSTS
TO 25 MPH WILL DEVELOP NORTH OF THE TROUGH FRI. WILL SEE DRIEST
CONDITIONS ALONG THIS TROUGH FRI AND SAT. INCREASING MOISTURE ON
SUN WILL ALLOW ISOLATED TO SCATTERED SHOWERS SUN ALONG THE TROUGH.

A SECOND LOW DEVELOPING NEAR MAGADAN WILL MOVE TO THE CHUKCHI SEA
AS A 1018 MB LOW BY 4AM SAT AND TO 150 NM NW OF BARROW AS A 1013
MB LOW BY 4PM SAT...THEN MOVE NORTHEAST. A COLD FRONT WITH THIS
FEATURE WILL MOVE TO MERGE WITH THE FIRST COOL FRONT BY 4AM
SAT...THEN TO POINT LAY TO NOME BY 4PM SAT...AND TO PRUDHOE BAY TO
MCGRATH BY 4PM SUN. EXPECT MIXED RAIN AND SNOW JUST AHEAD OF THE
FRONT CHANGING TO SNOW ALONG AND WEST OF THE FRONT. MAY SEE
SEVERAL INCHES OF SNOW ALONG THE WEST COAST WITH THIS. WILL ALSO
SEE A DRAMATIC DROP TO BELOW NORMAL TEMPERATURES WEST OF THIS
FRONT.

&&

.DISCUSSION...
MODELS INITIALIZE WELL AND SHOW SIMILAR SOLUTIONS THROUGH 4PM
FRI. AFTER THAT TIME THE GFS MOVES THE LOW ALONG THE WEST COAST TO
THE NORTHEAST FASTER THAN THE NAM AND MUCH FASTER THAN THE ECMF.
FAVOR THE FASTER GFS SOLUTION SINCE IT IS SUPPORTED BY A FAST
MOVING JET STREAK.

IN THE MEDIUM RANGE MODELS DIVERGE ON TIMING AND STRENGTH OF LOW
NORTH OF ARCTIC COAST MON AND ON STRENGTH OF RIDGE OVER INTERIOR
ALASKA NEXT WEEK.

&&

.FIRE WEATHER...
A WEAK THERMAL TROUGH WILL DEVELOP TONIGHT FROM MCGRATH TO DELTA
JUNCTION AND STRENGTHEN FRI...THEN MOVE TO DELTA TO EAGLE ON SAT
AND PERSIST THERE INTO SUN. NE WINDS 10-15 MPH WITH A FEW GUSTS
TO 25 MPH WILL DEVELOP NORTH OF THE TROUGH FRI. WILL SEE DRIEST
CONDITIONS ALONG THIS TROUGH FRI AND SAT WITH RH 15-25%.
INCREASING MOISTURE ON SUN WILL ALLOW ISOLATED TO SCATTERED
SHOWERS SUN ALONG THE TROUGH.

&&

.HYDROLOGY...
FREEZING LEVELS OF 5000-7000 FT OVER THE INTERIOR...WILL RISE TO
9000 FT FRI AND REMAIN HIGH INTO SAT. THIS WILL CAUSE HIGH LEVEL
SNOW TO MELT AND CAUSE WATER TO START FLOWING INTO INTERIOR RIVERS
THIS WEEKEND RAISING WATER LEVELS THERE.

OVER THE ARCTIC COASTS FREEZING LEVELS TO 5000 FT WILL PERSIST
INTO SAT CAUSING SNOW MELT TO START THERE.

OVER THE WEST COAST FREEZING LEVELS OF 3000-5000 WILL PERSIST
THROUGH FRI CAUSING HIGH LEVEL SNOW TO CONTINUE MELTING.

RIVER ICE IS REPORTED TO BE SLOWLY WEAKENING IN PLACE ON MOST
RIVERS RIGHT NOW AND WITH LOW RIVER LEVELS NO PROBLEMS HAVE BEEN
REPORTED.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FOR AKZ221-AKZ222-AKZ223-AKZ225-AKZ227.

SMALL CRAFT ADVISORY FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ230.
&&

JB MAY 14