Brisk Wind Advisory 139, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
211 PM AKDT SAT JUN 23 2012

.DISCUSSION...
ALOFT...RIDGE OVER EASTERN HALF OF THE STATE WILL SHIFT EAST INTO
CANADA THROUGH THE WEEKEND. VORTICITY MAX OVER NORTON SOUND MOVING
TO 60 MILE WEST OF POINT HOPE 4PM SUN AND CONTINUING NORTH. SEVERAL
LOWS WILL MOVE ACROSS THE SOUTH BERING SEA. THE FIRST LOW NEAR THE
PRIBILOFS WILL MOVE OVER SOUTHWEST ALASKA AND NORTON SOUND SUN
AND MON. THE SECOND ONE WILL MOVE ACROSS BRISTOL BAY MON TO THE
NORTHERN GULF OF ALASKA 4PM TUE. WITH THE FIRST LOW LIGHT TO
MODERATE SOUTHERLY FLOW WILL OCCUR OVER NORTHERN ALASKA WITH A
SHORT WAVE TROUGH MOVING NORTH TO NOME-FAIRBANKS-NORTHWAY 4PM SUN.
AS THE SECOND LOW MOVES INTO THE GULF OF ALASKA THE FLOW ACROSS
THE NORTHERN ALASKA WILL BECOME SOUTHEASTERLY MON NIGHT AND TUE
WITH A STRONG VORTICITY CENTER MOVING FROM THE CANADA BORDER NEAR
NORTHWAY TO DELTA JUNCTION BY 4PM TUE.

SURFACE...THERMAL TROUGH FROM GALENA TO FAIRBANKS WILL MOVE NORTH
OVERNIGHT TO LIE FROM KOBUK TO FORT YUKON 4PM SUN WHILE DEEPENING.
ON MON AND TUE THE TROUGH WILL THEN WEAKEN. HIGH PRESSURE OF 1015
MB NORTH OF BARTER ISLAND WILL DRIFT NORTHEAST.

MODELS...NEITHER NAM OR GFS INITIALIZING WELL ON WEAK VORT MAX
OVER NORTON SOUND THIS AFTERNOON WHICH MOVES NORTH...AND PRECIP
OUTPUT ALSO APPEARS LAGGING WITH THIS FEATURE. ON THE OTHER
FEATURES ALOFT AND AT SURFACE MODELS AGREE WELL. BOTH ARE
INDICATING SIGNIFICANT QPFS OVER SOUTHEAST INTERIOR TUE WITH
VORTICITY MAX APPROACHING DELTA JUNCTION. IN MEDIUM TERM MODELS
AGREE OK...THE SOUTHEAST FLOW WILL WEAKEN SOME AND A NEW LOW IN THE
HIGH ARCTIC DRIFTS SOUTH TOWARD ALASKA.

NORTH SLOPE...EAST WINDS INCREASING SOME AS HIGH DRIFTS NORTH AND
THERMAL TROUGH MOVES NORTH OVER INTERIOR. WINDS WILL DIMINISH SUN
NIGHT AS THERMAL TROUGH WEAKENS. EXPECT DIURNAL COASTAL FOG. AS
THERMAL TROUGH MOVES TO NORTHERN INTERIOR SUNDAY EXPECT ISOLATED
THUNDERSTORMS SUN PM OVER BROOKS RANGE.

WESTERN ALASKA...TONIGHT SCATTERED SHOWERS OR AREAS OF RAIN WILL
MOVE NORTH OVER THE COASTAL AREAS WHILE DIMINISHING FROM THE
SOUTH. ON SUNDAY RAIN WILL SPREAD NORTH AGAIN WITH A NEW VORTICITY
CENTER COVERING ZONES 214 AND 215 MOVING INTO 227 216 212 AND
211. WITH THE THERMAL TROUGH OVER ZONE 216 TONIGHT EXPECT
ISOLATED THUNDERSTORMS FOR THAT ZONE AND 227 THIS EVENING. WITH
THERMAL TROUGH MOVING NORTH AND STRENGTHENING SUN THIS WILL
PROVIDE SOME ISOLATED THUNDERSTORMS OVER AT LEAST ZONE 217 AND 216
NORTH OF GALENA. MONDAY NIGHT AND TUE THE VORT MAX WILL DRIFT
NORTH AND COVER MUCH OF THE REGION WITH SCATTERED SHOWERS.

CENTRAL AND EASTERN INTERIOR...WARM TEMPERATURES CONTINUING TODAY
AND SUNDAY WITH THE HIGH ALOFT BEING REPLACED BY SOUTHERLY
FLOW...THEN COOLING SOMEWHAT THEREAFTER AS FLOW BECOMES
SOUTHEASTERLY AND A BIT LIGHTER. THE FAVORED AREA FOR INSTABILITY
THIS AFTERNOON AND EVENING LIES SOUTH OF THE ARCTIC CIRCLE AND
EXPECT ISOLATED THUNDERSTORMS OVER THIS AREA....THOUGH SOUTHEAST
OF FAIRBANKS THERE APPEARS TO BE ENOUGH MOISTURE TO HAVE SCATTERED
THUNDERSTORMS. ON SUNDAY WITH THE THERMAL TROUGH MOVING NORTH
ZONES 218 219 220 AND NORTHERN 224 APPEAR THE BEST FOR
THUNDERSTORMS AND WITH THE THERMAL TROUGH EVEN STRONGER EXPECT
SCATTERED STORMS 218 AND AND 219. ON MONDAY THE THERMAL TROUGH
SHOULD BE WEAKER SO EXPECT LESS IN CONVECTION OVERALL...MAYBE
ISOLATED THUNDERSTORMS IN ZONE 218. ON TUESDAY HAVE MUCH OF THE
REGION SOUTH OF THE ARCTIC CIRCLE UNDER CHANCE OF SHOWERS BUT IF
THE VORT MAX MOVING TO DELTA JUNCTION CONTINUES TO BE AS STRONG AS
SHOWN BY MODELS THEN SIGNIFICANT RAIN WITH SOME HEAVY SHOWERS
WOULD OCCUR.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.FIRE WEATHER...THUNDERSTORM ACTIVITY MOVING NORTH SUNDAY WITH
HUMIDITIES RUNNING SOMEWHAT HIGHER OVER NORTHERN INTERIOR. SOUTH
WINDS DEVELOPING IN AK RANGE SUN. RED FLAG CONDITIONS MAY OCCUR
IN AK RANGE ZONES THEN IF HUMIDITIES DROP LOW ENOUGH.

&&

.HYDROLOGY...NONE FOR NOW. HIGH FREEZING LEVELS OVER ALASKA RANGE
IS CAUSING TANANA RIVER LEVELS TO RISE SOME DURING NEXT FEW DAYS.
SOME POTENTIAL FOR EXTENDED RAIN WITH LOCALLY HEAVY AMOUNTS
OVER SOUTHEAST INTERIOR EARLY NEXT WEEK...BEARS WATCHING AT THIS
TIME.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FOR AKZ220.
&&

JL JUN 12