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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