Small Craft Advisory 237, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
459 PM AKDT MON MAR 16 2015

.ANALYSIS AND UPPER LEVELS...

THE UPPER LEVEL PATTERN IS SIMILAR TO YESTERDAY EXCEPT THE TROUGH
IN THE EASTERN BERING SEA IS DIGGING SOUTHWARD PRODUCING SOUTH TO
SOUTHWEST FLOW ALOFT OVER SOUTHWEST MAINLAND AND SOUTHCENTRAL
ALASKA.

THE MAIN SURFACE LOW HAS MOVED INTO THE LOWER COOK INLET REGION
THIS AFTERNOON AND WILL RAPIDLY WEAKEN AS IT CONTINUES TO MOVE
NORTHWEST. A SECOND LOW NEAR THE EASTERN ALEUTIANS WILL DRIFT
SOUTHWEST AND THEN STRENGTHEN AGAIN AS ANOTHER LOW FROM THE NORTH
PACIFIC MERGES WITH IT TONIGHT.

&&

.MODEL DISCUSSION...

MODELS ARE IN BETTER OVERALL AGREEMENT THAN THEY WERE YESTERDAY.
THE BIGGEST ISSUE WAS THE HANDLING OF A LOW MOVING THROUGH THE
GULF FROM THE SOUTHEAST TUESDAY AND A LIKELY SOLUTION IS NOW
EMERGING. THE LOW MOVING THROUGH THE GULF WILL NOT BE ABLE TO
STRENGTHEN MUCH AS IT MOVES THROUGH THE GULF AS MOST OF THE ENERGY
WILL BE GOING INTO THE LOW NEAR DUTCH HARBOR. THAT LOW WILL
ACTUALLY ABSORB THE GULF LOW BY TUESDAY NIGHT. AFTER THAT THE
MODELS BEGIN TO STRUGGLE AGAIN IN THE GULF AS ANOTHER SERIES OF
WEAK LOWS MOVE THROUGH THE REGION IN THE SOUTHEAST FLOW.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2...TUE AND
WED)...THE UPPER LEVEL LOW THAT PUSHED THROUGH THE AREA MON WILL
BE A THING OF THE PAST BY TUESDAY...BUT IT WILL LEAVE ALL OF THE
AREA OPEN TO WARM AND MOIST SOUTHERLY FLOW FOR THE NEXT COUPLE OF
DAYS. TUESDAY WILL BRING A RELATIVE BREAK IN THE PATTERN. WINDS
WILL DIMINISH IN ALL AREAS AS THE GRADIENT RELAXES. TUESDAY IS
ACTUALLY SHAPING UP TO BE AN ALMOST "SPRING-LIKE" DAY FOR MANY
PLACES WITH TEMPERATURES REACHING INTO THE LOW 40S AND A DECENT
AMOUNT OF BREAKS IN THE CLOUD COVER. OVERNIGHT TUESDAY INTO
WEDNESDAY...THE NEXT SYSTEM WILL MOVE FROM THE NORTH PACIFIC
THROUGH THE GULF AND TOWARD SOUTH CENTRAL. THIS SYSTEM DOES NOT
LOOK NEARLY AS STRONG AS THE ONE FROM MONDAY. THERE WILL NOT BE
THE ANTECEDENT COLD AIR IN PLACE LIKE THERE WAS FROM OVER THE
WEEKEND. SO WHILE IT WILL BRING ANOTHER ROUND OF PRECIPITATION TO
COASTAL AREAS AS IT STRETCHES FROM YAKUTAT TO KODIAK ISLAND...IT
LOOKS LIKE IT WILL BE NEARLY ALL RAIN INSTEAD OF MIXED PRECIPITATION.
THIS SYSTEM FALLS APART ALONG THE NORTH GULF COAST...SO INLAND
LOCATIONS WILL BE HARD PRESSED TO SEE MUCH IN THE WAY OF PRECIPITATION.
ANOTHER WAVE FOLLOWS A NEARLY IDENTICAL TRACK LATE WEDNESDAY
REINFORCING THE DECAYING BOUNDARY OVER COASTAL AREAS. THIS WILL
KEEP WARM TEMPERATURES THROUGHOUT THE REGION WITH MORE RAIN MAINLY
CONFINED TO THE COAST.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
A STRONG CYCLONE MOVING NORTH ALONG THE SPINE OF THE ALASKA RANGE
WILL CONTINUE MOVING INTO THE WESTERN INTERIOR AND WEAKEN THROUGH
TONIGHT. ANOTHER WEAKER DISTURBANCE WILL THEN QUICKLY MOVE IN
THIS EVENING...BRINGING A SECOND ROUND OF SNOWFALL FROM WESTERN
BRISTOL BAY INTO THE KUSKOKWIM DELTA INTO TUESDAY WITH
ACCUMULATIONS UP TO 2 INCHES. WINDS ALONG COASTAL BRISTOL BAY
WILL INCREASE TONIGHT AS ANOTHER LOW MOVES NORTH TO THE WEST OF
THE AKPEN...BUT WIDESPREAD AREAS OF BLOWING SNOW SHOULD NOT BE A
PROBLEM AS WARM ADVECTION WILL WARM MOST AREAS RECEIVING SNOWFALL
TO AROUND 30 DEGREES BY TUESDAY MORNING. A THIRD SYSTEM BEGINS TO
MOVE TOWARD BRISTOL BAY FROM THE WESTERN GULF LATE
WEDNESDAY...BRINGING ANOTHER CHANCE OF RAIN AND SNOW.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE FOCUS OVER THE BERING SEA CONTINUES TO CENTER AROUND THE
COMPLEX LOW CENTERED NEAR DUTCH HARBOR. A LOW AND ASSOCIATED
FRONT CURRENTLY DEVELOPING OVER THE NORTH PACIFIC WILL BRING
ACTIVE WEATHER BACK TO THE AREA FOR TONIGHT THROUGH TUESDAY. THIS
NEXT LOW WILL BRING RAIN AND STRONG SOUTHERLY WINDS TO THE AKPEN
BEGINNING THIS EVENING...AND WILL BRING BLIZZARD CONDITIONS TO
THE PRIBILOF ISLANDS BY LATE TUESDAY MORNING THROUGH LATE TUESDAY
AFTERNOON AS THE LOW DRAGS A FRONT TOWARD THE AREA FROM THE EAST.

ANOTHER POTENTIAL AREA OF CONCERN LATER TUESDAY INTO WEDNESDAY
IS THE CENTRAL ALEUTIANS AS THE LOW NEAR THE EASTERN ALEUTIANS
DRIFTS WEST TOWARD THE AREA...BRINGING HEAVIER SNOW TOWARD THE
AREA IN THE PROCESS. ALONG WITH CONTINUED UNCERTAINTY OF WHERE
EXACTLY THE LOW WILL BE LOCATED...AS WELL AS HOW QUICKLY
TEMPERATURES WILL WARM AS THIS SYSTEM APPROACHES...WILL DECIDE
WHETHER SNOW WILL FALL IN A SUFFICIENT CHARACTER FOR THERE TO BE
ENOUGH BLOWING SNOW RESULTING IN SEVERE VISIBILITY REDUCTIONS.
WILL WITHHOLD ISSUING A WATCH AT THIS TIME GIVEN BUT WILL CONTINUE
TO WATCH THIS POTENTIAL WEATHER EVENT CLOSELY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...

MODELS SUPPORT THE IDEA THAT THE BROAD CYCLONIC JET SUPPORTING A
CUT-OFF UPPER LOW OVER THE AKPEN AND EASTERN ALEUTIANS WILL BUCKLE
THIS WEEKEND. THIS WILL ALLOW THE LOW TO MOVE SOUTHEAST INTO THE
PACIFIC. SURFACE FEATURES ARE NOT WELL HANDLED BY OPERATIONAL
MODELS AND WPC GUIDANCE ATTEMPTS TO CONSOLIDATE THE CONFUSION INTO
A REASONABLE SOLUTION BY USING A FAIR AMOUNT OF EC ENSEMBLE.

THE SURFACE LOW OVER DUTCH HARBOR WILL DISSIPATE...A WAVE MOVING
ALONG THE EASTERN FLANK OF THE UPPER LOW WILL MOVE INTO THE
EASTERN BERING SAT THROUGH SUN...AND A NEW NORTH PACIFIC FRONT
WILL SKIRT THE ALEUTIANS EARLY NEXT WEEK. THE FORECAST BRIEFLY
UTILIZES THE EC IN THE MID TERM WHICH TRANSITIONS INTO THE WPC
SOLUTION.

THIS WILL BRING SOME RAIN AND SNOW TO GULF COASTAL LOCATIONS WITH
LESSER AMOUNTS INLAND...AND SNOW SHOWERS TO THE ALEUTIANS THROUGH
MONDAY.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...BLIZZARD WARNING 195. WINTER WEATHER ADVISORY 145.
MARINE...STORM WARNING 173.
	GALE WARNING 120 121 130 131 137 138 139 150 155 170 172 174 175
	176 177 179.
	HEAVY FREEZING SPRAY WARNING 179 185.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...MO
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CC
LONG TERM...DS