textproduct: Fairbanks

KEY MESSAGES

Central and Eastern Interior... -Fire weather concerns remain elevated in the Upper Tanana Valley due to low chances of wetting rains, near-critical temperatures/RHs, and a non-zero chance for an isolated thunderstorm.

-Rain showers continue Tuesday (except for in the Upper Tanana), with up to 0.5 inches possible in the valleys and 0.5 to 1.25 inches of precipitation possible over terrain, with the highest amounts west of Fairbanks.

-Temperatures will be below normal Tuesday, with highs in the low/mid 60s throughout most of the region. Temperatures briefly warm on Wednesday as ridging builds into the Central and Eastern Interior. High temperatures are expected to be in the mid/upper 60s.

West Coast and Western Interior... -A Hydrologic Outlook is in effect until 4 PM Tuesday for headwater streams of the Koyukuk and Middle Yukon River Basins as 0.5-1.25 inches of rainfall has fallen so far, with another 0.5-1.25 inches possible through Tuesday, which may cause significant rises in smaller headwater streams. Showery conditions continue through the weekend, though precipitation totals will be lighter (<0.5 inches a day).

-Northerly winds continue in the Bering Strait through Wednesday evening, with gusts up to 45 mph expected.

-Another low is set to enter the Bering Sea on Friday. Model guidance is still not in agreement on location and specific intensity, though there is agreement that it will be weak.

North Slope and Brooks Range... -A Hydrologic Outlook is in effect until 4 PM Tuesday for headwater streams of the Koyukuk Headwaters as 1 inch of rainfall has fallen so far with another 0.5-1.25 inches possible through Tuesday, which may cause significant rises in smaller headwater streams. Rain continues in the Brooks Range and along the North Slope, with daily totals ranging from 0-0.5 inches and 0-0.25 inches respectively.

-Temperatures cool off on the North Slope Tuesday and Wednesday, with high temperatures in the mid/upper 50s from Point Lay south and upper 30s/40s north of Point Lay Tuesday and in the upper 30s/low 40s everywhere except for around Point Lay and Umiat (which will be in the low 50s) on Wednesday. Temperatures then warm into the mid 40s/mid 50s on the coast and into the 60s inland to finish out the week.

SHORT TERM /THROUGH FRIDAY NIGHT/

The upper level low that has been moving across the state over the last few days has moved into Canada, leaving weak troughing for most of Northern Alaska in its wake. Post-frontal showers linger in the Central and Northern Interior on Tuesday, with chances for a rumble of thunder or two in the White Mountains/Fortymile Country where temperatures have been warmer. Most lowland areas will see 0.5 inches of rain or less. Between 0.5 inches and 1.25 inches could fall over higher terrain in the Central and Northern Interior Tuesday, especially over southwest aspects. Northerly winds increase in the Bering Strait with continued cold air advection in the region, with the potential for gusts up to 45 mph.

On Wednesday, ridging builds into the Central and Eastern Interior from Fairbanks East, while two weak lows arrive on the West Coast- one over the Brooks Range and one over Bristol Bay. The low over Bristol Bay stays our of our AOR for now, while the low over the Brooks will bring another round of showers along the North Slope and in the Northwest Interior. Totals will be lighter than earlier this week, with 24 hour totals between 0.05 and 0.25 inches expected over lower terrain, with 0.25 to 0.5 inches over higher terrain. Ridging in the Central/Eastern Interior will briefly warm temperatures into the mid/upper 60s. If shortwaves being advected from the low over Bristol Bay arrive in the Upper Tanana Valley and/or Fortymile Country around/after peak heating, isolated thunderstorms could develop.

All 3 features shift east on Thursday. Isolated rain showers remain primarily in the Northern/Western Interior and on the West Coast, but few, if any, will be wetting. Another round of isolated thunderstorms is possible in the Upper Tanana/Fortymile Country on Thursday if the same conditions required on Wednesday are met. Another trough associated with a weak surface low into the Bering moves over Western Alaska on Thursday/Friday. There is disagreement both among ensemble members and between ensemble means in intensity and location, though the most aggressive members have the low bottoming out at only 980 hPa. Coastal flooding concerns are minimal to none at this time, since the system is quick-moving and wind gusts will be relatively calm (50+ mph gusts don't show up in the NBM until the 90th percentile). This low will also bring more widespread precipitation for the West Coast and Western Interior. Given the uncertainty of the low placement/strength there is considerable uncertainty in precipitation totals. This is especially true for the southern Seward Peninsula, because if flow is more southerly, orographic lift over the higher terrain in the middle of the peninsula will be much more effective than if flow is southwesterly/southeasterly. There is over 1 inch of spread between the NBM 25th and 75th percentiles around Nome for 24 hour precip totals on Friday.

LONG TERM /SATURDAY THROUGH MONDAY/

At the start of the long term period the low pressure that will bring moderate to heavy rainfall and gusty winds to parts of the West Coast, will be moving southeast towards the Gulf of Alaska. This low is paired with an arctic trough stemming from an area of low pressure in the high arctic. As these features move eastward it will bring isolated to scattered rain showers with it across the Eastern half of Northern Alaska. Behind this system a ridge of high pressure stemming from the North Pacific Ridge is expected to build into the Bering Sea. This ridge will help to influence the movement of lows in the North Pacific and Arctic as we move into early next week.

Model Ensembles are in good agreement on the ridge axis developing in the Bering Sea, and a strong Arctic low moving towards Wrangel Island in the Chuckchi Sea. Where models begin to diverge is how the low interacts with the ridge axis. This arctic low could potentially flatten and shift the ridge axis eastward. If this occurs we could see an atmospheric river develop and move onto the West Coast. The flattened ridge would allow for southwest flow to tap into tropical moisture and advecting it onto the West Coast. The GFS ensemble is much more aggressive in advecting this tropical moisture, but the ECMWF ensemble still has this southwest flow. Regardless of how strong the moisture advection will be, it could be a wet start for the work week across the West Coast and Western Interior.

Coastal Hazard Potential... No Coastal Hazards are expected in the forecast period.

FIRE WEATHER

Fire weather concerns will be quickly dropping over the next few days across much of Northern Alaska. Temperatures will be cooling across the Interior and Arctic Plains to the 50s/60s. These cooler temperatures will be accompanied with cloud cover and isolated to scattered rain showers. We will continue to see moderate rainfall up to an inch across the Koyukuk Valley and Central Brooks Range. Across the rest of the Western/Central Interior we can expect 0.10" to 0.40" of rainfall. This rainfall will steadily become more isolated as we move into Wednesday. There is a non zero chance that we could see a thunderstorm or two Tuesday afternoon across the Central/Eastern Brooks Range and in the higher terrain from Eagle Summit to Eagle.

The exception to fire weather concerns dropping will be the Upper Tanana Valley as downsloping will be able to persist Tuesday and Wednesday. Conditions will not be at the critical threshold like they were Monday afternoon, but over the next few days they will be near critical. Temperatures will slightly cool to around 70, and with downsloping the minimum RHs will be in the upper 20s. Winds in the valleys will generally be from the southwest and light, but during peak heating we could see some mixing occuring allowing for gusts of 20 mph to mix down into the valley. Overnight if the southwesterly winds persist similar to Tuesday morning there will not be that much recovery. As of now we dont expect these southwesterly winds to mix down into the valley for the next couple of nights, so the overnight RH recovery should be in the 70s. Rain chances don't return to the region till around Thursday afternoon, but they would come in the form of thunderstorms if they do develop. These chances are going to heavily rely on a wave of upper-level energy and if it moves through the region during the daytime. There is not a lot of model agreement on the timing, and we are continuing to monitor the feature.

HYDROLOGY

0.5 to 1.25 inches of rainfall has fallen across the Central Interior and Brooks Range in the past 24 hours. A stalled front will allow for an additional 0.5 to 1.5 inches of rainfall over the next 24 hours across the region. This could lead to river rises across the Koyukuk and the Middle Yukon Rivers headwaters. While no flooding is anticipated, some smaller creeks and streams could become bankfull.

AFG WATCHES/WARNINGS/ADVISORIES

AK...None. MARINE...Small Craft Advisory until 4 PM AKDT this afternoon for PKZ806- 807. Small Craft Advisory until 1 PM AKDT this afternoon for PKZ808- 855-856. Small Craft Advisory until 10 AM AKDT this morning for PKZ809. Small Craft Advisory until 10 AM AKDT this morning for PKZ854.