Small Craft Advisory 145, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
435 PM AKST SUN FEB 15 2015

.ANALYSIS AND UPPER LEVELS...
A DEEP 970 MB LOW IS APPROACHING THE ALASKA PENINSULA FROM THE
SOUTH AND BRINGING WITH IT A STRONG PUSH OF WARM MOIST AIR. THE
BULK OF THE WARM AIR IS HEADED TOWARDS THE SOUTHWEST AND NORTH
GULF COAST AND IS ACCOMPANIED BY STRONG WINDS. OVER THE SOUTHERN
PORTIONS OF MAINLAND ALASKA SOME WARM AIR STILL REMAINS FROM THE
PREVIOUS FRONT THAT PUSHED THROUGH.

&&

.MODEL DISCUSSION...
THE MODELS ARE IN GOOD AGREEMENT WITH THE MAIN LOW APPROACHING THE
ALASKA PENINSULA. THEY ARE ALL CLOSE WITH INTENSITY AND KEEP IT ON
THE SAME TRACK INTO THE EASTERN BERING AND TOWARDS NUNIVAK ISLAND.
HOWEVER...THERE ARE SOME DISCREPANCIES WITH ANOTHER LOW THAT IS
MOVING INTO THE GULF TUESDAY NIGHT. THE EC IS MUCH FARTHER EAST
THAN THE OTHER MODELS AND THE NAM IS LAGGING BEHIND. THIS PATTERN
GETS WORSE AS WE MOVE INTO WEDNESDAY.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE FRONT ASSOCIATED WITH THE LOW NEAR THE ALASKA PENINSULA WILL
MAKE IT TO THE NORTH GULF COAST THIS EVENING BRINGING RAIN WITH
IT. OVERNIGHT THE PRECIPITATION WILL ALSO PUSH INTO THE REST OF
THE SOUTHCENTRAL BUT THE QUESTION WILL BE HOW MUCH AND WHAT KIND.
WITH THE STRONG SOUTHEASTERLY FLOW THERE LOOKS TO BE ENOUGH
DOWNSLOPING TO KEEP THE MAJORITY OF THE PRECIPITATION AWAY FROM
AREAS EAST OF COOK INLET AND UP INTO THE MAT VALLEY.
HOWEVER...THERE REMAINS A POSSIBILITY THAT SOME SHOWERS WILL MAKE
IT INTO THOSE AREAS. TEMPERATURES ARE CURRENTLY JUST ABOVE
FREEZING FOR ANCHORAGE INTO THE MAT VALLEY AND ARE NOT EXPECTED TO
DROP TOO MUCH MOVING INTO THE NIGHT. THIS LEAVES SOME UNCERTAINTY
AS TO WHETHER RAIN OR FREEZING RAIN WOULD FALL LATE TONIGHT AND
EARLY MONDAY MORNING IF THOSE SHOWERS DO DEVELOP.

MONDAY AFTERNOON THERE WILL BE ANOTHER PUSH OF MOISTURE FROM THE
SOUTH THAT IS SUPPORTED BY A SHORT WAVE AND THE UPPER LEVEL FLOW
WILL SHIFT TO BECOME MORE SOUTHERLY. THIS GIVES HIGHER CONFIDENCE
IN PRECIPITATION BECOMING MORE WIDESPREAD. BUT THERE SHOULD BE
ENOUGH WARM AIR WITH THIS SECOND PUSH TO KEEP MOST AREAS IN RAIN.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

A LARGE LOW PRESSURE SYSTEM WILL MOVE THROUGH THE EASTERN BERING
TONIGHT THROUGH TUE. DURING THIS TIMEFRAME AN ASSOCIATED FRONT
WILL BRING WARM AIR INTO SW AK WITH MAINLY RAIN AND GUSTY WINDS IN
THE BRISTOL BAY ZONE...AND SNOW IN THE KUSKOKWIM VALLEY. AS THE
WARM AIR OVERRUNS COLD AIR AT THE SURFACE IN THE KUSKOKWIM
DELTA...PERIODS OF FREEZING RAIN WILL DEVELOP TONIGHT THROUGH
MONDAY MORNING...AND AGAIN MONDAY EVENING. PRECIPITATION WILL THEN
CHANGE TO A MIX OF RAIN AND SNOW THROUGH TUESDAY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

LOW PRESSURE MOVING INTO THE EASTERN BERING WILL BRING RAIN AND
SNOW AND STRONG WIND TO THE EASTERN ALEUTIANS AND AKPEN
TONIGHT...BECOMING ALL RAIN MON THROUGH TUE. THE PRIBILOFS WILL BE
MAINLY SNOW TONIGHT WITH SIGNIFICANT BLOWING SNOW THROUGH MID
MORNING ON MON. AT THAT TIME RAIN WILL BEGIN TO MIX WITH THE SNOW
AND THIS WILL PERSIST INTO TUE. THE WESTERN ALEUTIANS WILL HAVE
RAIN AND SNOW SHOWERS ON PERSISTENT NORTHEAST FLOW THROUGH TUE.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE MODEL SPREAD REGARDING THE LOW MOVING INTO THE GULF TUESDAY
NIGHT LENDS RELATIVELY LOW CONFIDENCE TO THE PRECIPITATION
FORECAST FOR SOUTHCENTRAL ALASKA DURING THE MIDDLE OF THE WEEK. A
FARTHER EAST SOLUTION WOULD KEEP MOST OF THE ACTIVITY CONFINED TO
THE EASTERN GULF...WHEREAS A MORE WESTERN TRACK TOWARDS PRINCE
WILLIAM SOUND WOULD BRING MORE WIDESPREAD PRECIPITATION TO THE
AREA. FOR NOW...THE FORECAST REFLECTS A MORE EASTWARD TRACK FOR
THE LOW AND THUS A LOWER CHANCE OF PRECIPITATION THROUGH
WEDNESDAY. WILL CONTINUE TO MONITOR MODEL TRENDS IN THE COMING
DAYS.

AFTER THAT...CONFIDENCE REMAINS LOW WITH RESPECT TO INDIVIDUAL
DISTURBANCES MOVING TOWARDS THE MAINLAND FROM THE NORTH
PACIFIC...BUT THE GENERAL CONSENSUS IS FOR A WARM AND MOIST
PATTERN TO CONTINUE THROUGH NEXT WEEKEND AS A RIDGE OVER THE WEST
COAST OF NORTH AMERICA KEEPS BROAD SOUTHERLY FLOW FOCUSED ON THE
MAINLAND AND PARTICULARLY ALONG THE GULF COAST. THE BERING WILL
ALSO REMAIN IN A SHOWERY REGIME BENEATH CYCLONIC FLOW ALOFT.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...DK
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DS
LONG TERM...CB