The NAM is giving a number of 1.50" of liquid through 10 pm this eve and considering the fact that the Head is starting out colder than expected. at least half of that liquid could equate to 10-12" and as temperatures get a little milder with the nearing of the face this afternoon snow amounts will be smaller. We are even look at amounts up to 2 feet. Winds are even on tap to increase today as the frontal boundary nears. Another 0.40" of fluid is expected to come tonight through Friday which would be to 3 or 4 inches.
Older post:
It's been a while since we have seen a full luck for up to 2 feet of snow above 2500 ft. A real deep low will track north into the Behring Sea and offer an occluded front our way. As the front nears us the southerly flow aloft will increase and bring moisture with it in the frame of coke for lots of the region starting Thursday morning. Once the open region of the face makes it through the country by Thursday afternoon then it should be capable to pull milder air (forcing the precip. to mix with rain or changing to rain altogether) into the Port and tied into the Lowe River valley just under the Pass. Also the strong southerly flow will also induce chinook winds north of the Head which would provide for temperatures into the 30s and 40s and rain. If this happens then when the precipitation ends by Friday night then there could be a considerable quantity of fog that develops in the areas that see rain. Gusty east to south winds to 35 mph will be experienced at the Pass (Thursday) but since the blow will be wet it likely won't get blown around as often as drier snow would.
This morning's run of the GFS gives us 39 mm (1.53") of swimming and if you have been following the posts it has been fluctuating from 1.50 all the way up to 2.00". At any place we could see a foot and a half of the white stuff fall at the Head and higher amounts in the colder reaches of higher elevations. Once the movement moves through expect southerly flow to fall in strength which will slow down the inflow of moisture. Could see showery weather Friday evening through the weekend. Showers are sometimes difficult to call so there is the opportunity to see a small bit more snow over the weekend. But we will experience a respectable measure of dusty air above us combined with the stronger April sun with available moisture we should see some decent showers around.
Temperatures should be near freezing from the Run up to around 3500 ft during this snow event. There could be some clearing north of the Pass Friday night, but fog may prevent temperatures from cooling off. Expect 20s at nighttime and 30s during the day over the weekend.
The lookout for next week we will see a passage to a convention with a ridge over the Bering Sea and offshore flow. This will bring moderately strong gap winds, drier conditions, more sun, cooler temperatures especially in the mornings with temperature inversions but by late morning into afternoon expect them to break. The upper ridge in the Bering will avail to get some colder Siberian air downward into Alaska, but the heat of the sun should serve to change the air mass faster than if it were the heart of the winter.
This is the NAM forecast of moisture centered over Valdez. you can see how rich the moisture is from the rise all the way up to 30,000 feet ahead of the occluded front.
No comments:
Post a Comment