099
FXAK69 PAFG 181324
AFDAFG
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
524 AM AKDT WED SEP 18 2019
DISCUSSION
SYNOPSIS...A WEATHER FRONT WILL SPREAD RAIN TO THE SOUTHERN
INTERIOR TODAY TAPERING TO SHOWERS TONIGHT. THE SOUTHEAST INTERIOR
WILL BE IN THE RAIN SHADOW SO WILL ONLY SEE A FEW SPRINKLES AT
BEST. THE ARCTIC WILL REMAIN MOSTLY CLOUDY TO CLOUDY WITH A MIX
OR RAIN AND SNOW SHOWERS. THE WEST COAST WILL BE PARTLY TO MOSTLY
CLOUDY WITH COOLER TEMPERATURES.
MODELS...RUN TO RUN CONTINUITY IS GOOD AND 18/00Z SOLUTIONS ARE
IN VERY GOOD AGREEMENT THROUGH ABOUT 48 HOURS. THERE CONTINUES TO
BE SOME DISAGREEMENT ON POSITION AND STRENGTH OF THE LOW OVER THE
CHUKCHI SEA AND ITS EVOLUTION AS IT ABSORBS A COUPLE OF LOWS
BEYOND 48 HOURS. PRECIPITATION SOLUTIONS ARE SIMILAR, SO WILL USE
A BLEND FOR LOCATION, AND THE SREF TO INCREASE THE PROBABILITIES.
ALOFT...AT 500 HPA...A TRIO OF LOWS OVER THE AREA WITH A 525 DAM
LOW OVER THE CHUKCHI SEA, A 528 DAM LOW OVER DEADHORSE, AND A 531
DAM LOW OVER THE SOUTHWEST MAINLAND. WEAK RIDGING OVER THE
SOUTHEAST MAINLAND WILL SLIDE OVER CANADA AS THE LOWS ROTATE WITH
THE LOW OVER THE CHUKCHI SEA MOVING OVER THE CENTRAL CHUKCHI SEA
AT 523 DAM, THE LOW OVER DEADHORSE MOVING 50 NM OF PRUDHOE BAY,
AND THE LOW OVER THE SOUTHWEST MAINLAND MOVING NORTH OVER SELAWIK
AS IT MERGES WITH THE LOW OVER THE CHUKCHI SEA. A STRONG SHORTWAVE
ASSOCIATED WITH THE LOW OVER THE SOUTHWEST MAINLAND WILL LIE FROM
SELAWIK TO KING SALMON THIS AFTERNOON, AMBLER TO MCGRATH AND SOUTH
THIS EVENING, ALLAKAKET TO KANTISHNA EARLY THURSDAY, AND OVER THE
ALCAN BORDER BY THURSDAY AFTERNOON. WEAK RIDGING WILL MOVE OVER
THE THE STATE SOUTH OF THE BROOKS RANGE BEHIND THE SHORTWAVE WITH
SOUTHWEST FLOW ACROSS THE AREA. THE LOWS OVER THE ARCTIC WILL
CONTINUE TO ROTATE WITH THE LOW OVER THE CHUKCHI SEA MOVING OVER
THE CHUKOTSK PENINSULA COAST AT 525 DAM, AND THE LOW IN THE ARCTIC
MOVING TO 200 NM NORTH OF POINT BARROW AT 527 DAM. A STRONG
SHORTWAVE WILL MOVE AROUND THE CHUKCHI SEA LOW TO LIE OVER 170W BY
THURSDAY MORNING. THE SHORTWAVE WILL MOVE OVER THE SOUTHWEST
MAINLAND BY THURSDAY EVENING AS THE LOW NORTH OF POINT BARROW
MERGES WITH THE LOW OVER THE CHUKOTSK PENINSULA BY FRIDAY MORNING.
BROAD CYCLONIC FLOW ALOFT WILL PERSIST OVER THE STATE. AT 850
HPA...0C ISOTHERM LIES FROM OLD CROW YT TO LIVENGOOD TO SCAMMON
BAY THEN SOUTH OF ST MATTHEW ISLAND THIS MORNING. BY THURSDAY
MORNING IT WILL LIE FROM OLD CROW YT TO MINCHUMINA TO BETHEL AND
SOUTHWEST. BY FRIDAY MORNING IT WILL LIE FROM OLD CROW YT TO
TANANA TO TOGIAK.
SURFACE...BROAD AREA OF CYCLONIC FLOW OVER THE STATE AND ARCTIC
WITH A 1001 MB LOW 50 NM NORTH OF DEADHORSE THIS MORNING, 1003 MB
LOW OVER POINT HOPE, AND THE PRIMARY LOW OVER KUSKOKWIM BAY AT 987
MB. WEAK HIGH PRESSURE IS OVER THE UPPER YUKON FLATS. BY THIS
AFTERNOON THE LOW IN KUSKOKWIM BAY WILL BE IN THE FORTYMILE
COUNTRY AT 990 MB WITH A SECOND LOW NEAR MINCHUMINA AT 991 MB. THE
LOWS OVER THE ARCTIC WILL DISSIPATE. WEATHER FRONT ASSOCIATED WITH
THE PRIMARY LOW WILL MOVE INTO THE ALASKA RANGE AND SOUTHERN
INTERIOR THIS MORNING SPREADING RAIN NORTH OVER THE MIDDLE TANANA
VALLEY. THIS EVENING THE LOW WILL MOVE TO THE UPPER YUKON FLATS AT
992 MB WITH TROUGHING EXTENDS SOUTHWEST TO A 996 MB LOW NEAR
MCGRATH THEN SOUTHWEST TO THE PRIBILOFS. A 1000 MB LOW WILL
DEVELOP NEAR DEMARCATION POINT LATE THIS MORNING AND MOVE TO POINT
BARROW BY THURSDAY MORNING, THEN INTO THE CHUKCHI SEA BY FRIDAY
MORNING AT 998 MB. WEAK HIGH PRESSURE WILL DEVELOP BETWEEN THE
RANGES BEHIND THE FRONT THURSDAY AFTERNOON.
ARCTIC COAST AND BROOKS RANGE...A MIX OF RAIN AND SNOW SHOWERS
WILL CONTINUE ON AND OFF THE NEXT COUPLE DAYS AS LOW PRESSURE
REMAINS OVER THE AREA. TEMPERATURES WILL CONTINUE TO TREND DOWN
WITH LOWS IN MOST AREAS AROUND 30. WINDS GENERALLY NORTH TO
NORTHEAST TO 10 MPH.
WEST COAST AND WESTERN INTERIOR...SHOWERS GENERALLY SOUTH OF
GALENA TODAY AND TONIGHT. PARTLY TO MOSTLY CLOUDY FOR THE
REMAINDER OF THE AREA. WINDS NORTH TO NORTHEAST AT 5 TO 15 MPH.
TEMPERATURES WILL CONTINUE TO SLOWLY COOL.
CENTRAL AND EASTERN INTERIOR...RAIN HAS MOVED INTO THE SOUTHERN
INTERIOR AND WILL CONTINUE INTO THE AFTERNOON BEFORE TAPERING TO
SHOWERS. SHOWERS WILL PERSIST THROUGH THURSDAY. RAINFALL AMOUNTS
WILL BE LESS THAN 0.50 INCH. SNOW MAY MIX WITH THE RAIN AT HIGHER
ELEVATIONS, AND IN AREAS NORTH OF THE YUKON RIVER. WINDS GENERALLY
NORTH TO NORTHEAST TO 10 MPH EXCEPT NEAR EASTERN ALASKA RANGE
PASSES WHERE WIND ADVISORIES ARE IN EFFECT FOR SOUTH WINDS 20 TO
30 MPH GUSTING TO 55 MPH.
COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE.
FIRE WEATHER
SHOWERS IN THE LOWER YUKON DELTA AND THE CENTRAL
AND EASTERN INTERIOR TODAY. TEMPERATURES COOLING, RELATIVE
HUMIDITY VALUES ABOVE 40 PERCENT WITH EXCELLENT OVERNIGHT
RECOVERY. WINDS GENERALLY NORTH TO NORTHEAST 5 TO 15 MPH. SOME
GUSTY GAP WINDS NEAR ALASKA RANGE PASSES TODAY TO 55 MPH.
HYDROLOGY
NO AREAS OF CONCERN AT THIS TIME.
EXTENDED FORECAST FOR DAYS 4 TO 7...GENERALLY CLOUDY AND SHOWERY
CONDITIONS WILL CONTINUE. TEMPERATURES WILL BE COOLING.
AFG WATCHES/WARNINGS/ADVISORIES
WIND ADVISORY FOR AKZ224-AKZ226.
SMALL CRAFT ADVISORY FOR PKZ200-PKZ210.
SDB SEP 19
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