Small Craft Advisory 43, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
137 PM AKDT TUE JUL 12 2011

.DISCUSSION...
CURRENT OCCLUDED FRONT OVER WESTERN INTERIOR WILL FALL APART
WITHIN THE NEXT 12 HOURS...HOWEVER SOUTHWEST TO WEST FLOW WILL
CONTINUE OVER MOST OF THE INTERIOR AND THIS WILL CONTINUE TO
SPREAD MOISTURE INTO NORTHERN ALASKA THROUGH THURSDAY. A BREAK OFF
UPPER LEVEL LOW WILL SHOOT OFF FROM THE MAIN UPPER LEVEL LOW AND
END UP IN THE SOUTHEASTERN PORTION OF THE INTERIOR. ALL OF THE
MODELS ARE PUTTING COPIOUS AMOUNTS OF PRECIPITATION OVER THIS AREA
IN SOUTHERN ZONE 224...226 AND 223 BY WED EVENING. IF THIS COMES
TRUE...WE MAY VERY WELL HAVE HYDRO ISSUES THRUST UPON US AS THE
MODELS ARE GENERATING QPF AMOUNTS IN THE 2 INCH RANGE OVER 24 HOUR
PERIOD.

MODELS IF FAIRLY CLOSE AGREEMENT THROUGH ABOUT 60 HOURS. AFTER
THAT TIME FRAME THE MODELS BEGIN TO DIVERGE GREATLY. THE GFS AND
THE ECMWF TAKE THE BERING STRAIT LOW EASTWARD TO THE WESTERN
INTERIOR BY EARLY FRI MORNING BUT WITH POSITIONING AND STRENGTH
DIFFERENCES. THE ECMWF IS A MUCH COLDER AND LOWER HEIGHT FEATURE
WHILE THE GFS IS ALTHOUGH WELL BELOW NORMAL HEIGHT IS ABOUT 70 DM
HIGHER THAN THE ECMWF. THE POSITION IS ALSO A DIFFERENCE WITH THE
ECMWF POSITIONED NEAR EMMONAK AND THE GFS UPPER LEVEL LOW IS
POSITIONED NEAR KALTAG. ECMWF MOVES THE UPPER LEVEL LOW NORTHWARD
WHILE THE GFS MOVES THE LOW DUE EASTWARD SO THAT THE ECMWF LOW IS
ON THE BROOKS RANGE NORTH OF AMBLER AND THE GFS LOW IS NEAR
MINCHUMINA BY SAT EVENING. THE ECMWF IS MUCH COLDER AT 850H THOUGH.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.FIRE WEATHER...
AN UPPER LEVEL LOW OVER ST LAWRENCE ISLAND WILL MOVE OVER THE WESTERN SEWARD
PENINSULA THURSDAY. SOUTHWEST FLOW WILL BRING SCATTERED RAIN SHOWERS OVER MOST
OF WESTERN ALASKA AND THE INTERIOR THIS AFTERNOON AND EVENING. SHOWERS ARE
EXPECTED TO BECOME MOSTLY ISOLATED OVER THE CENTRAL AND EASTERN INTERIOR
TONIGHT AND WEDNESDAY. THE END OF THIS WEEK WILL SEE AN INCREASE IN RAIN
AND RAIN SHOWERS AS THE UPPER LOW MOVES EAST. MINIMUM RH VALUES WILL GENERALLY
BE ABOVE 40 PERCENT AND NO WET THUNDERSTORMS FOR THE NEXT SEVERAL DAYS.

&&

.HYDROLOGY...NONE AT THIS TIME. HOWEVER...THE SOUTHEASTERN
INTERIOR MAY EXPERIENCE HEAVY RAINFALL BEGINNING WED EVENING AND
LAST THROUGH MUCH OF THU WHILE THE PRECIPITATION SHIELD MOVES
NORTHWARD ALONG THE ALCAN BORDER AND JUST WESTWARD A BIT.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY FOR PKZ200-PKZ210-PKZ220-PKZ225.

GALE WARNING FOR PKZ210-PKZ220.
&&

CF JUL 11