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FGAK78 PACR 312339 CCA
ESFAK

Hydrologic Outlook
NWS Alaska Pacific River Forecast Center Anchorage AK
400PM AKDT FRI MAY 31 2024


...UPDATED BREAKUP OUTLOOK USING AN EXPERIMENTAL GRAPHICAL FORMAT...


The Alaska-Pacific River Forecast Center is updating the format of
its breakup outlook and summary products. The new experimental
format proposes to move to a more graphical presentation, away from
the historically text-based product below. The likelihood of
flooding from snowmelt and/or ice jams is initially calculated based
on the flood frequency for the current 2000 to 2021 historical
record and adjusted to reflect current conditions. The experimental
graphical format Alaska Spring Breakup Outlook products are posted
to the Alaska-Pacific River Forecast Center website at:
www.weather.gov/aprfc/breakupProducts


A direct link to the latest graphical product is:
www.weather.gov/media/aprfc/BreakupProducts/ESFAK_ACR_20240531.pdf


...Spring Breakup and Flood Potential Outlook for Alaska...
Current Conditions as of May 31:
* With the exception of the North Slope rivers, all major river
  systems across the state are completely open and ice free.
* Along the North Slope there is a fairly uniform, though shallow,
  snowpack remaining from the winter.  Snow along the lower
  elevation northern slopes of the Brooks Range has been greatly
  depleted from recent warm temperatures.
* Rivers on the North Slope are beginning to open up.   * The
  Sagavanirktok River is mostly open down to about the Franklin
  Bluffs with areas of aufeis seen further downstream.  Water is
  flowing out of the mouth into the Arctic Ocean.  Webcams along the
  Sag river and a UAF river gage all show water levels have been
  steadily rising this week, though still well within bank.
   * The Kuparuk River is also beginning to open up though there
  seems to still be plenty of in-place ice on the lower half of the
  river.  Water on top of ice can be seen at the mouth of the river.
   * The Colville River has plenty of open areas and separated ice
  sheets along most of the river, especially at and a little bit
  downstream of the confluence with the Anaktuvuk River, which is
  mostly open.  Water can be seen flowing out of the river mouth
  over in-place sea ice.
* Water levels at Fort Yukon have dropped through the week after
  cresting earlier this week.  The Porcupine River has steadily
  receded this week, though recent warm temperatures have restarted
  snow melt in the headwaters causing the Porcupine at Old Crow to
  begin to rise.  Forecast Conditions
* Temperatures are expected to fall well below average across the
  North Slope this weekend through mid week, with temperatures
  generally ranging between the mid 20s and mid 30s.  Snow is also
  likely during the first half of next week.  This will slow breakup
  along the rivers until warmer temperatures arrive by the end of
  next week.
* For the Porcupine, temperatures are expected to warm into the mid
  60s-70s through the weekend, leading to increased snowmelt rates
  in the headwaters and slowly rising water levels in Fort Yukon by
  next week, though no flooding is expected.

Forecast Conditions
* Temperatures are expected to fall well below average across the
  North Slope this weekend through mid week, with temperatures
  generally ranging between the mid 20s and mid 30s.  Snow is also
  likely during the first half of next week.  This will slow breakup
  along the rivers until warmer temperatures arrive by the end of
  next week.
* For the Porcupine, temperatures are expected to warm into the mid
  60s-70s through the weekend, leading to increased snowmelt rates
  in the headwaters and slowly rising water levels in Fort Yukon by
  next week, though no flooding is expected.

The Climate Prediction Center temperature outlook for the 2nd week
of June indicates an increased chance of warmer than normal
temperatures for the northern half of Alaska and normal temperatures
for the rest of the state, except for the southwest coast, where
there is a slight tilt towards cooler than normal temperatures.

This will be the final Spring Breakup Outlook for the season.

KVP