Scientific Forecaster Discussion

NWS Discussion
			
				

Northern Alaska forecast discussion 
National Weather Service Fairbanks Alaska 
348 am akdt Sat may 18 2013 


Discussion... 
aloft...deep long wave trough over western Alaska extending from 
Kodiak to northwest of wrangel island continues to rotate eastward 
with axis over central Alaska Sunday evening. A weak short wave 
rounding the bottom of the long wave separates and continues east 
into the southern Yukon while most of the energy rotates northward 
into the Arctic as an upper level ridge builds into the southern 
Bering Sea Sunday and into southwest Alaska Monday. The upper 
level ridge continues to build into central Alaska into next week 
with a gradual warm up to more seasonal temperatures. 


Surface...very cold air mass for middle of may entrenched over 
western and central Alaska with very strong cold front moving east 
out of eastern Alaska into the Yukon at this time. Paor dropped 
from the low 60s yesterday afternoon ahead of the front to snow 
and the upper 20s this morning. Many locations in the western 
interior have dropped into the middle teens while low visible and snow 
with temperatures in the middle 20s are found across the central 
interior. Winter storm warnings hoisted for eastern Brooks range 
and eastern Alaska Range look to be on track with reports of 
nearly two feet of snow near Black Rapids Glacier in eastern 
Alaska Range. Over a quarter of an inch of snow fell at valley 
level in Fairbanks yesterday while reports of 1 to 2 inches fell 
in the hills above 1500 feet. Expect similar snow fall across the 
interior today with less than 1 inch in the valleys and 1 to 2 
inches above 1500 feet. Winter weather advisories hoisted for 
zones 220...221...222...223 and zone 224 with another 1 to 2 
inches of snow expected to fall today...especially above 1500 
feet. 


Models...are in good agreement on main features in the short and middle 
terms however considerable model and run to run spread exists in 
the long term which reduces forecaste confidence to below normal. 
Gradual warming indicated into the middle of next week. 


&& 


Fire weather... 
none 


&& 


Hydrology... 
breakup in progress on the upper Yukon river and will proceed 
slowly over the next couple of days with unseasonable cold 
temperatures. More snow melt is expected next week as temperatures 
warm across the central and eastern Alaska. Flood Watch for ice 
jam flooding for the Yukon river for Circle City. 


&& 


Afg watches/warnings/advisories... 
Winter Storm Warning for akz218-akz225-akz226. 


Flood Watch for akz220. 


Winter Weather Advisory for akz220-akz221-akz222-akz223-akz224. 


Brisk Wind Advisory for pkz200-pkz210-pkz220-pkz225-pkz230- 
pkz240-pkz245. 
&& 


$$ 


Ccc may 13