textproduct: Fairbanks

SYNOPSIS

Red Flag Warnings are scattered across the Interior once again due to lightning and dry fuels. Similar to yesterday, the SW Interior and Northern Interior will be the hot spot again, but we will see an uptick in activity along the AlCan Border as well. Otherwise, a front has dropped temperatures dramatically on the North Slope and brought a return of stratus/fog to the area. Then in the Interior, we were moderately confident in heavy rain occurring this weekend, however, the main source of energy that was causing this rain is drifting too far south and east to bring very impactful rain. However, we are still expecting rain, though not as heavy as initially thought.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Red Flag Warnings in effect for the AlCan Border and Northern Interior, particularly around the Dalton, Allakaket and south slopes of the Brooks Range.

- Temperatures remain warm through Saturday, then take a tumble on Sunday as a front brings rain and cooler temperatures.

- What was once heavy rain, looks to be more of a light to moderate rain from Saturday afternoon through Sunday with 0.25 to 0.50" around the Interior, heaviest in the Northern Interior due to upslope flow.

- The one caveat is downpours and thunderstorms which will make locally higher amounts this weekend.

West Coast and Western Interior... - Red Flag Warning in effect for the SW Interior from McGrath to St. Mary's to Kaltag. Numerous thunderstorms will develop once again this evening.

- Heavy rain is likely in these thunderstorms with localized spots receiving over 1" of rain, especially under the most persistent storms.

- A cooling trend arrives this weekend with continued chances for showers.

- The Kobuk Valley has been warm and dry, but there is an increasing chance for showers and a period of rain by Sunday and into early next week as a front approaches from the south.

North Slope and Brooks Range.. - Much colder in the Plains and along the coast today with highs in the 30s to low 40s and areas of stratus and fog.

- A gradual warm up is expected into the weekend and next week as a front brings more southerly flow.

- The Brooks Range will get some rainfall on Sunday and into Monday with localized areas approaching 0.5" to 1.0", especially on the south facing slopes. Lighter showers expected north of Range.

FORECAST ANALYSIS AND DISCUSSION

The overall pattern is the same, but moving forward is quite different than what we saw yesterday. The main difference is with the orientation/movement of a shortwave over the Gulf and and the front moving through from the Bering Sea Low.

To get into the pattern, we have a 539 decameter low over the Central Bering, an elongated shortwave trough in the eastern Gulf which extends to Washington state and a 516 decameter low in the Arctic. In the middle of this is a ridge in Canada which is extending into the Interior. The elongated trough is still going to break off of the parent low, however the front moving from west to east from the Bering is a bit slower and will aid in pushing this vorticity maximum out. Yesterday, it was slightly faster and phased with the vort max which then prompted it to lift north and unleash a firehose of moisture. Today, every piece of model guidance pushes the main energy away from Alaska. This leaves us with a more typical front moving south to north. In the Interior, expect a front on Saturday which pushes north of the AK Range during the afternoon and evening. Thunderstorms will precede this front on the north side during this time, then showers and will follow. Around 0.25" inches can be expected in the southern Interior with around 0.5" in the northern Interior. Needless to say, if there are persistent heavier showers and storms, some spots will receive higher amounts. However, the heaviest widespread rain will now be in the upslope areas of the southern Brooks Range where up to 1" is still possible. This front will also approach the very dry northwest Interior and Kobuk Valley on Sunday. This is increasing chances for wetting rains there and may put the fire season on a brief pause.

Otherwise, the weather does not look too impactful heading into next week, but given the model inconsistencies within 48 hours, I am taking them with a grain of salt.

FIRE WEATHER

Red Flag Warnings are in effect for SW AK, the Northern Interior, Central Brooks Range and Eastern Interior for lightning. The most robust lightning activity is expected in the SW Interior and around Coldfoot this evening.

Ridging across the Interior will continue today bringing another warm day for most. Temperatures will continue to rise into the 70s and low 80s across the Interior Valleys. The main areas of concern for relative humidity will be the Kobuk and Lower Koyukuk Valleys with RHs bottoming out around 25%. Sustained winds are expected to remain mostly less than 15 mph but gusts may approach 18 to 20 mph at times this evening.

Saturday and Sunday will see a major pattern shift as a low in the Bering Sea brings a front from south to north over most of Northern Alaska. Compared to yesterday, wetting rains are still likely for most of the area north of the Alaska Range, but the heavy rain (1.00"+) is no longer expected in the Interior. In general, the southern Interior should receive around 0.25" of rain with localized higher amounts under persistent thunderstorms. The northern Interior should see the heaviest rain, especially near the southern slopes of the Brooks Range with upwards of 0.50". The southern Slopes of the Brooks Range may receive near 1" of rain.

Temperatures will be much cooler by Sunday with widespread high temps in the 60s across Northern Alaska. RHs will also be much higher with minimums in the 40s and 50s. A cool and wet trend continues through early next week.

HYDROLOGY

Rain is still expected in the Interior and Denali National Park area this weekend, but with much lower rainfall totals than models initially suggested. River rises are expected in conjunction with this precipitation but because water levels are normal (low) these rises will not result high or impactful water levels.

The heaviest rain will likely be along the southern Brooks Range and northern Interior, but it does not seem too impactful as of now.

See water.noaa.gov for current and forecast water levels.

EXTENDED FORECAST DAYS 4-7

An active weather pattern is expected to continue throughout the week as multiple areas of low pressure influence the state. A trough stretching from Southcentral Alaska northward into the Arctic gradually shifts east through midweek as a low slowly moves inland from the Bering Sea. This Bering system will bring the greatest chances for precipitation to Western Alaska Wednesday before showers spread eastward across portions of the Interior on Thursday. Meanwhile, ridging remains anchored over the Gulf of Alaska and western Canada, helping keep much of the Eastern Interior comparatively drier through much of the period. By Friday, however, another low in the Bering may move into the Gulf while an Arctic low drops farther south towards the Bering Strait. Scattered showers remain possible across much of the Interior and Brooks Range, though confidence in the exact location and timing of precipitation decreases late in the week as model solutions begin to diverge.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Red Flag Warning for AKZ926-929-930-952. Red Flag Warning for AKZ912-931>933-935. PK...Small Craft Advisory for PKZ806. Brisk Wind Advisory for PKZ810. Small Craft Advisory for PKZ811. Small Craft Advisory for PKZ812-857. Small Craft Advisory for PKZ854. Small Craft Advisory for PKZ856.