967
FXAK69 PAFG 121456
AFDAFG
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
656 AM AKDT SUN JUL 12 2020
SYNOPSIS
HIGHLIGHTS ARE:
DENSE FOG ALONG THE YUKON DELTA AND BERING STRAIT WILL DIMINISH
LATE THIS MORNING.
A WEAK LOW PRESSURE TROUGH OVER THE BROOKS RANGE WILL PERSIST
THROUGH TONIGHT. THIS WILL CAUSE SCATTERED SHOWERS AND ISOLATED PM
THUNDERSTORMS THROUGH THIS EVENING OVER ZONES 218 AND 219.
A THERMAL LOW PRESSURE TROUGH THAT STRETCHES FROM CHICKEN
TO FAIRBANKS TO ANVIK WILL REMAIN IN PLACE TODAY, THEN MOVE NORTH
TO OLD CROW TO BETTLES TO ANVIK BY MON AFTERNOON, THEN WEAKEN IN
PLACE THROUGH TUE. MOISTURE ALONG AND SOUTH OF THIS TROUGH WILL
MOVE NORTH ON MON. SCATTERED SHOWERS AND ISOLATED PM THUNDERSTORMS
WILL OCCUR ALONG AND JUST SOUTH OF THIS TROUGH TODAY, AND SHOWERS
WILL SPREAD NORTH ON MON AND BECOME SCATTERED TO WIDESPREAD ON MON
WITH ISOLATED THUNDERSTORMS THROUGH THE DAY.
EXPECT HIGHS IN THE 70S AND MIN RH IN THE 22-42% RANGE TODAY OVER
THE INTERIOR, WITH THE DRIEST CONDITIONS OVER THE YUKON FLATS.
TEMPERATURES WILL COOL ON MON AND RH WILL RISE. SCATTERED SHOWERS
AND NEAR NORMAL TEMPERATURES WILL CONTINUE TUE THROUGH NEXT
WEEKEND.
ALOFT...
THE LONG WAVE PATTERN CONSISTS OF A RIDGE STRETCHING FROM THE
BERING SEA NORTH TO THE NORTH POLE, AND A TROUGH OVER MAINLAND
ALASKA. AS A SERIES OF SHORT WAVE TROUGHS MOVE SOUTHWEST OVER
WESTERN ALASKA THE LONG WAVE TROUGH WILL RETROGRADE AND ELONGATE
FROM ALASKA INTO NE RUSSIA ON MON AND TUE, WITH WEAK WESTERLY
ZONAL FLOW DEVELOPING OVER NORTHERN ALASKA BY TUE AND CONTINUING
THROUGH FRI. THIS WILL CAUSE SCATTERED SHOWERS AND NEAR NORMAL
TEMPERATURES TUE THROUGH NEXT WEEKEND.
ONE LOW ALOFT NEAR MCGRATH WILL MOVE SOUTHEAST TODAY. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS WITH THIS FEATURE WILL MOVE
SOUTHEAST TODAY.
A SHORT WAVE FROM OLD CROW TO MCGRATH WILL MOVE TO EAGLE TO DENALI
BY 4PM SUN, THEN WEAKEN, THERE WILL BE SCATTERED SHOWERS AND
ISOLATED PM THUNDERSTORMS ALONG AND SE OF THIS FEATURE.
A SECOND SHORT WAVE OVER THE WESTERN NORTH SLOPE WILL MOVE TO
ARCTIC VILLAGE TO AMBLER BY 4PM SUN, TO ARCTIC VILLAGE TO MCGRATH
BY 4AM MON, AND THEN PERSIST INTO MON PM. EXPECT SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS ALONG THIS TROUGH TO SPREAD SOUTH
TONIGHT, WITH SHOWERS BECOMING WIDESPREAD ALONG THE TROUGH MON,
WITH THUNDERSTORMS ALONG AND EAST OF THE TROUGH ALL DAY ON MON.
SURFACE...
HIGH PRESSURE FROM THE CHUKCHI SEA SOUTH OVER THE BERING SEA
WILL PERSIST THROUGH MON. THIS IS CAUSING STRATUS AND FOG ALONG
NORTH FACING SHORES OF WEST COAST, AND ALONG MUCH OF THE ARCTIC
COAST, WHICH WILL CONTINUE THROUGH MON.
AN ARCTIC COLD FRONT THAT LIES FROM BARTER ISLAND TO POINT LAY
WILL MOVE SOUTH ALONG THE BROOKS RANGE TODAY AND THEN WEAKEN IN
PLACE ON MON. THIS IS BRING MUCH COLDER AIR TO THE NORTH SLOPE
WEST OF DEADHORSE TODAY, AND WILL BRING A CHANCE OF SNOW TO THE
AREA WEST OF DEADHORSE THROUGH TONIGHT.
A WEAK LOW PRESSURE TROUGH OVER THE BROOKS RANGE WILL PERSIST
THROUGH TONIGHT. THIS WILL CAUSE SCATTERED SHOWERS AND ISOLATED PM
THUNDERSTORMS THROUGH THIS EVENING OVER ZONES 218 AND 219.
A THERMAL LOW PRESSURE TROUGH THAT STRETCHES FROM CHICKEN
TO FAIRBANKS TO ANVIK WILL REMAIN IN PLACE TODAY, THEN MOVE NORTH
TO OLD CROW TO BETTLES TO ANVIK BY MON AFTERNOON, THEN WEAKEN IN
PLACE THROUGH TUE. MOISTURE ALONG AND SOUTH OF THIS TROUGH WILL
MOVE NORTH ON MON. SCATTERED SHOWERS AND ISOLATED PM THUNDERSTORMS
WILL OCCUR ALONG AND JUST SOUTH OF THIS TROUGH TODAY, AND SHOWERS
WILL SPREAD NORTH ON MON AND BECOME SCATTERED TO WIDESPREAD ON MON
WITH ISOLATED THUNDERSTORMS THROUGH THE DAY.
DISCUSSION
AT 00Z, MODELS INITIALIZE WELL ALOFT AND SHOW SIMILAR SOLUTIONS
THROUGH 4PM MON. AFTER THAT TIME, THE NAM IS A BIT FASTER THAN THE
GFS AND ECMF BRINGING A SHORT WAVE AND MOISTURE INTO THE WEST
COAST OF ALASKA ON MON NIGHT AND TUE. PREFER THE SLOWER GFS AND
ECMF SOLUTIONS FOR MON NIGHT AND TUE, SINCE THE LONG WAVE TROUGH
SHOULD BE SLOW IN RETROGRADING.
WITH PRECIPITATION, THE NAM HAS A SMALL AREAL COVERAGE TODAY THAN
THE GFS AND ECMF. SINCE THE NAM COVERS A SMALL AREA THAN
IS CURRENTLY OCCURING, FAVOR THE BROADER AREAL COVERAGE SHOWN BY
THE GFS AND ECMF.
AT THE SURFACE, MODELS VERIFY WELL AT 06Z, AND SHOW SIMILAR
SOLUTIONS THROUGH 4PM MON, THEN THE NAM MOVES THE LOW FROM
SIBERIA INTO THE WEST COAST OF ALASKA MORE QUICKLY THAN THE GFS
AND ECMF. FAVOR THE GFS AND ECMF FOR REASONS STATED ALOFT.
BOTTOM LINE, IS WE FAVOR A BLEND OF THE GFS AND ECMF THROUGH TUE.
COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE.
FIRE WEATHER
A WEAK LOW PRESSURE TROUGH OVER THE BROOKS RANGE WILL PERSIST
THROUGH TONIGHT. THIS WILL CAUSE SCATTERED SHOWERS AND ISOLATED
PM THUNDERSTORMS THROUGH THIS EVENING OVER ZONES 218 AND 219.
A THERMAL LOW PRESSURE TROUGH THAT STRETCHES FROM CHICKEN
TO FAIRBANKS TO ANVIK WILL REMAIN IN PLACE TODAY, THEN MOVE NORTH
TO OLD CROW TO BETTLES TO ANVIK BY MON AFTERNOON, THEN WEAKEN IN
PLACE THROUGH TUE. MOISTURE ALONG AND SOUTH OF THIS TROUGH WILL
MOVE NORTH ON MON. SCATTERED SHOWERS AND ISOLATED PM THUNDERSTORMS
WILL OCCUR ALONG AND JUST SOUTH OF THIS TROUGH TODAY, AND SHOWERS
WILL SPREAD NORTH ON MON AND BECOME SCATTERED TO WIDESPREAD ON MON
WITH ISOLATED THUNDERSTORMS THROUGH THE DAY.
EXPECT HIGHS IN THE 70S AND MIN RH IN THE 22-42% RANGE TODAY, WITH
THE DRIEST CONDITIONS OVER THE YUKON FLATS. TEMPERATURES WILL COOL
ON MON AND RH WILL RISE. SCATTERED SHOWERS AND NEAR NORMAL TEMPERATURES
WILL CONTINUE TUE THROUGH NEXT WEEKEND.
HYDROLOGY
MOST AREA ON SAT HAS LESS THAN 0.25 INCH OF RAIN. WITH ANOTHER
0.25-0.50 INCH EXPECTED IN THE ALASKA RANGE TODAY THROUGH MON,
COULD SEE RISES ON ALASKA RANGE STREAMS, BUT NOT FLOOD ISSUES.
&
AFG WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY FOR PKZ210.
JB JUL 20
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