Flash Flood Warning 1, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
242 PM AKDT WED JUN 30 2010

.DISCUSSION...

UPPER AIR: MODELS IN AGREEMENT THROUGH SAT. DEFORMATION ZONE OVER
WESTERN INTERIOR WASHES OUT BY THU MORNING. LOW PRESSURE OVER
SOUTHEAST BERING SEA ROTATES OVER THE PRIBILOFS. RIDGE OVER
BEAUFORT SEA WILL WEAKEN THU. NORTH POLE LOW WILL REMAIN NORTH OF
80N.

SURFACE: 1003 MB MACKENZIE BAY LOW SHOULD WEAKEN THU AS 1018 MB
HIGH OVER ARCTIC OCEAN BUILDS TO 1022 MB. THERMAL TROUGH OVER
NORTHERN INTERIOR WILL DRIFT SOUTH TO THE CENTRAL INTERIOR ON THU.
1002 MB LOW NEAR PRIBILOFS WILL PERSIST THROUGH SAT. WEAK LOW WILL
FORM OVER THE NORTHERN GULF OF ALASKA THU NIGHT THEN DISSIPATE
SAT.

NORTH SLOPE: MESOSCALE NORTH WIND OVER THE EASTERN BEAUFORT SEA
COAST WILL TAKE ON A LARGER SCALE DIRECTION ON THU AS MACKENZIE
BAY LOW COLLAPSES DUE TO HIGH PRESSURE BUILDING OVER THE ARCTIC.
THIS WILL END THE LIGHTING STRIKES OVER ZONE 204 WITH A RATHER DRY
PERIOD AND BOUTS OF STRATUS CONTINUING...AND POSSIBLE SMALL CRAFT
ADVISORIES DEVELOPING BY FRI.

WEST COAST: STUBBORN SOUTHEAST BERING SEA LOW AND THERMAL TROUGH
EXTENDING WEST FROM THE INTERIOR WILL PROVIDE MOISTURE AND ENERGY
TO THE SEWARD PENINSULA...NULATO HILLS AND ADJOINING AREAS TO FUEL
AFTERNOON AND EVENING CONVECTION THROUGH SAT. GRADIENT OFF OF
BERING SEA LOW IS NOT EXPECTED TO BE TIGHT ENOUGH FOR MARINE
ADVISORIES.

INTERIOR: ISOLATED AFTERNOON AND EVENING THUNDERSTORMS WILL
PERSIST THROUGH THE WEEKEND. SEE FIRE WEATHER. RIVER RISES WILL
ALSO BE AN ISSUE. SEE HYDROLOGY.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.FIRE WEATHER...RH'S WILL CONTINUE ABOVE 30%...WITH HIGHEST RH'S
TO 60+% OVER THE ALASKA RANGE AND SOUTHEAST INTERIOR. THIS
EVENING... THUNDERSTORMS WILL BE MOST PROMINENT OVER THE NORTHERN
AND WESTERN INTERIOR. FOR THU PM...NAM20 LI'S OF ZERO TO -4C WILL
BE PREVALENT OVER THE ENTIRE INTERIOR...THOUGH THERE WILL CONTINUE
TO BE ENOUGH MOISTURE TO KEEP THE THUNDERSTORMS WET.

&&

.HYDROLOGY...OBSERVATIONS FROM THE CHESANA AND NEBESNA RIVERS
SHOW A POSSIBLE FALL ALREADY UNDERWAY. THE FORECAST CREST FOR THE
TANANA RIVER AT BIG DELTA MAY BE SIGNIFICANTLY IMPACTED BY THIS
NEW INFORMATION.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
FLOOD WARNING FOR PARTS OF ZONES 223-224-226.

&&

JUN 10

DA