Small Craft Advisory 35, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
1242 PM AKDT THU JUL 7 2011

.DISCUSSION...
SYNOPTIC SCALE MODELS IN GOOD AGREEMENT THROUGH SATURDAY WITH UPPER
LEVEL TROUGH REMAINING IN PLACE OVER THE BERING SEA. BOTH THE GFS
AND ECMWF CONTINUE TO DEPICT THE 500MB LOW NOW CENTERED JUST
SOUTH OF ST LAWRENCE ISLAND MOVING SLOWLY TO THE SOUTH AND WEST
AND WEAKENING. A WEAK RIDGE IS NOTED OVER WESTERN YUKON AND
EASTERN ALASKA WHILE HIGH PRESSURE ALOFT IS NOTED OVER THE HIGH
ARCTIC. THE UPPER LEVEL LOW IN THE BERING IS PROGGED TO WEAKEN AS
IT CONTINUES TO WOBBLE SOUTH AND WEST IN THE CENTRAL BERING SEA
THOUGH THE WEEKEND AND BEYOND. 12Z ECMWF RUN IS IN BETTER AGREEMENT
WITH THE 12Z GFS THAN WAS THE 00Z RUN WITH AN UPPER LEVEL LOW
MOVING WEST AND SOUTH OUT OF THE CANADIAN HIGH ARCTIC TO THE NORTH
SLOPE AND BROOKS RANGE OVER THE WEEKEND AND EARLY NEXT NEXT WEEK.

SATELLITE IMAGERY REVEALS OCCLUDED LOW IN THE BERING SEA JUST WEST
OF ST MATTHEW ISLAND WITH WEAK FRONT STRETCHING FROM PAMC
NORTHWESTWARD TO PATC. MOSTLY CLEAR SKIES NOTED IN THE WESTERN AND
CENTRAL INTERIOR WITH RAPIDLY BUILDING TCU NOTED ON VISUAL IMAGERY
TO THE EAST OF PAFA. SATELLITE ALSO REVEALING RAPID DEVELOPMENT OF
THUNDERSHOWERS IN THE CENTRAL AND EASTERN INTERIOR AS UPPER LEVEL
EASTERLY WAVE CONTINUES TO MOVE WEST INTO THE CENTRAL INTERIOR.
THERMAL TROUGH IS NOTED ALONG A SOUTHEAST TO NORTHWEST LINE FROM
PAEG TO PABL.

PAFA SOUNDING ALONG WITH FORECASTED SOUNDINGS REVEALING FAVORABLE
CONDITIONS FOR THUNDERSTORMS THIS AFTERNOON AND EVENING ACROSS
THE CENTRAL AND EASTERN INTERIOR WITH CAPE PROGGED TO BE NEAR 650
IN THE EARLY AFTERNOON INCREASING TO NEAR 1000 BY EVENING. LIFTED
INDEX VALUES BETWEEN MINUS 2 AND MINUS 4. THE ATMOSPHERE WILL
LOOSE ITS CAP BY EARLY AFTERNOON AS THE EASTERLY WAVE CONTINUES TO
MOVE WEST. THUNDERSTORMS WITH BRIEF HEAVY RAIN HAIL AND GUSTY
WINDS ARE EXPECTED TO DEVELOP THIS AFTERNOON AND CONTINUE WELL
INTO THE EVENING. CONVECTION FIRING UP ON RADAR ATTM. WILL NEED TO
MONITOR POTENTIAL FOR TRAINING THUNDERSTORMS DROPPING HEAVY RAIN
ON RECENTLY RAIN SOAKED TERRAIN ESPECIALLY AS MANY RIVERS AND
SMALL STREAMS IN THE CENTRAL AND EASTERN INTERIOR CONTINUE TO RUN
HIGH.

COASTAL HAZARD POTENTIAL DAYS
3 AND 4...NONE

&&

.FIRE WEATHER...AFTERNOON AND EVENING WET THUNDERSTORM ACTIVITY
WITH VARIABLE AND GUSTY WINDS OVER MUCH OF THE INTERIOR AND BROOKS
RANGE.

&&

.HYDROLOGY...
NO LARGE SCALE RAINFALL EVENTS ARE EXPECTED HOWEVER LOCALLY HEAVY
RAIN COULD OCCUR WITH TRAINING THUNDERSTORMS THIS AFTERNOON AND
EVENING.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY FOR PKZ210-PKZ225-PKZ230.
&&

CC JUL 11