912
FXAK67 PAJK 191433
AFDAJK
SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
533 AM AKST TUE NOV 19 2019
SHORT TERM
RAIN AND HEAVY RAINS ARE MOVING INTO SOUTHEAST
ALASKA FROM THE WEST IN A SLOW MOVING SOUTH TO NORTH ORIENTED
ATMOSPHERIC RIVER. THE SOUTHERN PANHANDLES RAIN IN MORE DELAYED
AND THEY SHOULDN'T SEE THE LARGER RAIN TOTALS UNTIL WEDNESDAY INTO
THURSDAY. SPECIAL WEATHER/HYDRO STATEMENTS HAVE BEEN ISSUED FOR
THE QUANTITY OF RAIN EXPECTED AND POSSIBILITY OF FLOODING ISSUES.
STILL SOME COOLER AIR AT WHITE PASS LEVEL, AND THE WARMER AIR WILL
NOT SPREAD INTO THAT ARE UNTIL LATER TUESDAY NIGHT SO A WET SNOW
ABOVE 2500 FEET OR SO IS EXPECTED. WHITE PASS TEMPERATURES ARE
UPPER 20S ON TUESDAY MORNING. SNOW ACCUMULATIONS LIKELY TO START
AFTER NOON, WITH THE BETTER SNOW RATES TUESDAY EVENING TO A FEW
HOURS AFTER MIDNIGHT. AM EXPECTING 4 TO 7 INCHES OF SNOW TO FALL
THROUGH TUESDAY NIGHT. BREEZY WINDS WITH GUST TO 40 MPH OVER NIGHT
WOULD BE EXPECTED TO BLOW SNOW AROUND, HOWEVER, WITH THE
TEMPERATURES WARMING AND EVENTUALLY MIXING RAIN INTO THE SNOW, NOT
EXPECT BLOWING SNOW OR WHITE OUT CONDITIONS.
A WARM TONGUE OF AIR WITH THE SLOW MOVING FRONT WILL HAVE TEMPS
IN TO THE MID TO 40S OR NEAR 50 TODAY, AND A COUPLE OF DEGREES
WARMER FOR WEDNESDAY. SOME OF THESE TEMPERATURE COULD BE BE WITHIN
REACH OF RECORD WARMTH FOR THE DAY. OVERALL CONFIDENCE OF A WET
AND WARM NEXT COUPLE OF DAYS IS HIGH. LOCALIZED PONDING OF WATER
IN LOW LYING AREAS AND RAPID RISES TO STREAMS AND RIVERS WILL
OCCUR, WE WILL MONITOR THE RIVERS AND STREAMS FOR THREAT OF MINOR
FLOODING.
LONG TERM
THURSDAY OUR FIRST ATMOSPHERIC RIVER OVER THE
PANHANDLE BEGINS TO PUSH EAST INTO CANADA BEFORE PRIMING SOILS
ACROSS THE SOUTHERN PANHANDLE FOR SOME FLOODING POTENTIAL LATE IN
THE WEEK. THERE ARE STILL ISSUES YET TO SOLVE AS THE THE GFS
HOLDS ON TO A SLIGHTLY SLOWER INITIAL STORM EXIT THURSDAY. BUT AS
A RESULT, IT ALSO ESCORTS THE LATE WEEK SYSTEM AS MUCH AS 9 HOURS
BEHIND THE ECMWF AND THE NAM. WHETHER ONE SOLUTION SUGGESTS ONE
STORM IS EXITING AND ANOTHER MOVES THAT A SECOND IS ENTERING, THE
MEANING TO MOST SOUTHEAST ALASKANS IS THAT THE WEEK WILL
DEFINITELY END WITH RAIN AND LOTS OF IT. AND HYDROLOGY AND A
POSSIBILITY OF SOME FLOODING WILL BE ISSUE ONE FOR THE NEXT
SEVERAL DAYS AS DETAILS EMERGE. BOTH THE NAEFS AND THE ECMWF
ENSEMBLE INDICATE PW VALUES OF 3 STANDARD DEVIATIONS HIGHER THAN
NORMAL DURING THE HEART OF THE WET SEASON TUESDAY THROUGH THURSDAY
NIGHT. ASIDE FROM THE RAIN, WE DID INCREASE WINDS THROUGH THE
INNER CHANNELS ON THURSDAY AND THURSDAY NIGHT AS THE RAIN WILL NOT
ARRIVE WITHOUT WIND.
THE EXTENDED FORECAST DOES POSE MORE CHALLENGES FOR HIGHER
ELEVATIONS. AFTER THE FIRST STORM EXITS, THE SECOND WILL COME IN
WITH LOWER SNOW LEVELS ALLOWING THE HEAVIER PRECIPITATION TO FALL
AS SNOW. THUS THE KLONDIKE HIGHWAY AT WHITE PASS COULD SEE THE
FIRST SIGNIFICANT SNOWFALL FOR THE REGION LATE THURSDAY INTO EARLY
FRIDAY. A WINTER STORM WATCH MAY NEED TO BE CONSIDERED AS
CONFIDENCE RISES.
DETAILS BECOME MURKIER FOR THE WEEKEND, BUT ALL ENSEMBLES COOL
TEMPERATURES ACROSS SOUTHEAST AND THE GULF IN ONSHORE FLOW, SO
MUCH SO THAT WE INTRODUCE THE POSSIBILITY OF SOME SNOW MIXING IN
WITH RAIN SHOWERS OVER THE NORTHERN PANHANDLE EARLY NEXT WEEK. BUT
AT THIS STAGE, WE DO NOT EXPECT ANY ACCUMULATIONS. ONSHORE FLOW
OFTEN DISAPPOINTS FOR SNOW LOVERS AS THE BOUNDARY LAYER IS OFTEN
TOO MOIST FOR SUBSTANTIAL SNOW-MELT COOLING TO OCCUR. THE SOUTHERN
PANHANDLE WILL CONTINUE TO NEGATE SHORT-TERM IMPACTS OF THE
MODERATE DROUGHT CURRENTLY IN EFFECT.
AVIATION
PATCHY FOG EARLY THIS MORNING ACROSS THE SOUTHERN
PANHANDLE, WHERE BREAKS IN THE CLOUDS ALLOWED BETTER RADIATIVE
COOLING TO REACH SATURATION POINT. NORTHEASTERN GULF COAST HAVE
LOWER CLOUDS WITH START OF THE RAIN FROM INCOMING FRONTAL BAND AND
ATMOSPHERIC RIVER. LOCALIZED MARGINAL TO IFR CONDITIONS FROM THE
LOWER CEILINGS. WINDS ALOFT WILL BE INCREASING THROUGH THE DAY AS
THE FRONT APPROACHES SO WILL NEED TO WATCH FOR LLWS IN THE
YAKUTAT AND SITKA AREAS.
MARINE
GALES DEVELOPING OVER THE NORTHERN GULF COASTAL WATERS
AS THE FRONT MOVES ACROSS THE GULF. SOUTHERLY WINDS IN LYNN CANAL
INCREASING TO 30 TO 35 KT FOR TUESDAY INTO TUESDAY NIGHT. SEAS OUT
OVER THE GULF INCREASING ABOVE 15 FEET FOR STRONG SOUTHERLY FLOW
AND FOLLOWING SEAS/SWELL.
HYDROLOGY
HYDRO OUTLOOK AND SPECIAL WEATHER STATEMENT (SPS)
OUT FOR THE SE AK AND THE NORTHEAST GULF COAST. TWO ATMOSPHERIC
RIVERS OVER THE NEXT 2 TO 5 DAYS, THE NORTHEAST GULF COAST
EXPECTS 5 TO 6 INCHES IN THE YAKUTAT AREA TO WEDNESDAY. THE
PANHANDLE SHOULD BE SEEING 2 TO 4 INCHES. THIS WILL MEAN HIGH
RIVER AND LAKE LEVELS THROUGH MID-WEEK. HOWEVER, NO FLOODING IS
EXPECTED WITH THIS SYSTEM. STRONG WINDS IN AREAS OF STEEP TERRAIN
MAY POSE A RISK OF MUDSLIDES.
AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...WINTER WEATHER ADVISORY FROM NOON TODAY TO 5 AM AKST WEDNESDAY
FOR AKZ018.
STRONG WIND FROM 3 PM AKST THIS AFTERNOON THROUGH LATE TONIGHT
FOR AKZ018.
MARINE...GALE WARNING FOR PKZ012-051-052.
SMALL CRAFT ADVISORY FOR PKZ013-021-022-031-032-034-041>043-053.
BEZENEK/JWA
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