KSLC → 21AK

Executive Summary

This is a summer convective/terrain day — the primary concern is not a widespread weather system but rather localized convection near departure, afternoon heating turbulence over interior terrain, and critically, the complete absence of a TAF or reliable forecast for the arrival airport (21AK, Montana Creek near Talkeetna). At KSLC, the TAF shows VFR conditions with SCT130 and light southerly winds at the 14:00Z ETD — a clean departure window. The western and Pacific Northwest portions of the route are largely benign at 9,000 ft. The biggest operational risk is arriving at a remote Alaskan airstrip without any terminal forecast, in mountainous terrain where local conditions can change rapidly. MARGINAL GO — proceed only after obtaining the best available Alaska-area weather information (Talkeetna ASOS, PANC TAF trend, Alaska FSS briefing) and confirming acceptable conditions along the Susitna Valley corridor. The single most important trigger: any confirmed ceiling below 600 ft AGL or visibility below 2 SM in the Talkeetna/Montana Creek area at or near your ETA changes this to a NO-GO.

Route Hazards

Before Departure — What to Recheck

• Alaska weather — most critical item: Call Alaska FSS (1-800-WX-BRIEF) or check PANC TAF, Talkeetna ASOS (PATK), and any available PIREPs in the Susitna Valley / Talkeetna Mountains corridor. Confirm ceilings and visibility at 21AK vicinity meet your personal minimums (600 ft / 2 SM) at your estimated arrival time of approximately 02:26Z July 8.
• Convection at KSLC: Check current radar and any updated SIGMETs for the Salt Lake City area. The AFD noted the main thunderstorm threat was 00–04Z with storms possible off the Oquirrh Mountains. Verify storms have cleared before 14Z departure. If radar shows active cells within 20 nm of the field, delay until clear.
• TFR confirmation: NOTAM 6/3018 (Provo, UT — surface to 400 ft) is active at ETD; NOTAM 6/3019 (Sun Valley, ID — surface to 400 ft) starts at ETD. Both are surface-only and should not conflict with cruise, but verify your filed route is clear of both TFR areas before taxi. Also confirm NOTAM 6/3017 (26NM W Yakima — surface to 9,000 ft) has expired as scheduled at 04:00Z before departure — it is scheduled to end about 10 hours before ETD, but confirm it has not been extended.
• Hazard TFRs near Pendleton OR and Chelan WA: NOTAM 6/3022 (15NM E Pendleton, surface to 8,000 ft) and NOTAMs 6/3023, 6/2958, 6/3024 near Chelan/Wenatchee are active during the flight window. At 9,000 ft you will be above most of these, but verify your route does not penetrate these areas below 9,000 ft during any descents.
• Winds aloft update: Check the 12Z or 00Z winds aloft forecast for stations along the route (SLC, BOI, GEG, YXC, YYC toward Alaska) for any significant headwind or crosswind component updates that could affect fuel planning.
• Fuel planning for a 12+ hour flight: Distance is 1,867 nm; estimated block time is roughly 747 minutes. Confirm fuel reserves are adequate for contingencies including a possible divert from 21AK.
• Alternate planning: Identify a solid alternate in the Talkeetna/Wasilla/Palmer area. PATK (Talkeetna Airport) is the closest identifiable alternate. Confirm alternates have forecast conditions meeting your alternate personal minimums (1,000 ft / 3 SM) near your ETA.

Leaving KSLC — Departure at 2026-07-07 14:00Z

The TAF group valid at your 14:00Z ETD is FM070600: 15006KT, P6SM, SCT130. This is a clean VFR departure — scattered clouds at 13,000 ft MSL, light southerly winds at 6 kt, visibility greater than 6 SM. No precipitation, no convection in the forecast at departure time.

At generation time, KSLC was reporting scattered towering cumulus and broken layers between 11,000 and 25,000 ft with very light winds — a summertime convective environment. The AFD noted thunderstorm activity between 00–04Z with possible outflow winds up to 30–40 kt overnight, but these should be clearing well before your 14:00Z departure. Verify via morning radar that any overnight storm activity has cleared the departure corridor.

Departure density altitude at KSLC is operationally significant — at generation time the field was reporting approximately 7,476 ft density altitude in the afternoon heat. At 14:00Z the air will still be warm; account for reduced climb performance accordingly. The departure is effectively VMC with a potential for residual morning convective debris — verify radar before start.

The PROB30 group (00–04Z) showed possible TSRA with gusty winds and broken cumulonimbus; this window expires well before your ETD. The next FM group after departure (FM071800: 30009KT, P6SM, SCT140) shows afternoon wind shift to northwest with continued VFR — departure timing at 14Z catches the favorable morning/midday window.

The Ride at 9,000 ft

Winds Aloft

No winds aloft data was explicitly provided for this briefing. Based on synoptic pattern analysis from the surface prog charts, here is what the pattern suggests for the route corridor at 9,000 ft MSL:

• KSLC departure (Great Basin): Light southerly to variable flow near the surface; light westerly flow at cruise altitude typical for July. Afternoon pressure gradient weak. Expect minimal headwind component initially.
• Idaho / Montana corridor: A frontal system is positioned across the northern Rockies and northern tier states per the 18Z Tue surface prog (valid at your approximate enroute time). Flow ahead of this boundary could produce increased southwesterly component winds at altitude over southern Montana/Idaho — possible 15–25 kt headwind component in this segment. Confirm with updated winds aloft forecast before departure.
• Pacific Northwest (OR/WA): High pressure dominating the eastern interior; light to moderate westerly flow. Minimal headwind component through this segment.
• British Columbia / Alaska corridor: Flow becomes more northwesterly as you approach Alaska. The 18-hr surface prog shows the Pacific High well-established. Winds at 9,000 ft over southern Alaska likely light to moderate from the west or northwest. No component should exceed your 40 kt headwind personal minimum based on available synoptic data, but confirm with actual winds aloft forecast.

Critical note: At 1,867 nm and roughly 747 minutes estimated block time, even a 10–15 kt average headwind materially affects fuel. Pull the current winds aloft forecast before departure and recompute.

Ride Quality

The GTG turbulence product at FL090 valid near your departure time (Tue 12Z) shows light to moderate turbulence (yellow-green EDR values) over the Idaho/Montana mountain terrain. The main areas of concern at 9,000 ft:

• Wasatch Front / Uintas departure: Afternoon heating turbulence — expect light chop to light turbulence climbing out of KSLC over the mountains. This is the typical summertime fare.
• Idaho / Montana terrain: GTG at FL090 shows persistent yellow areas (light-moderate) over the higher terrain. With afternoon solar heating still active at 14:00Z departure, expect light to moderate turbulence over the elevated terrain. Smooths progressively as you get into lower terrain of eastern Washington.
• Pacific Northwest / inland: Smooth to light chop. High pressure dominating, minimal forcing.
• Alaska approach corridor: The PIREP from BIG (UA at FL065, MOD turbulence, BE23, approximately 53°N 180°W area) is roughly consistent with light to moderate ride over the lower Alaska terrain. CDV PIREP at FL040 showed negative turbulence on approach. KTN at FL100 showed light occasional moderate turbulence surface to FL100.

The G-AIRMET Turb/LLWS at +12hr (valid Tue 06Z) shows high-level turbulence (FL300–FL430) well above your cruise altitude — not applicable to your 9,000 ft flight. No low-level turbulence G-AIRMET is depicted at +12hr, which is consistent with a generally benign low-level ride except over active terrain heating.

Overall ride quality forecast: Smooth to light chop over the Great Basin and Pacific Northwest; light to moderate turbulence expected over Idaho and Montana mountain terrain, particularly during the first several hours of the flight when afternoon heating is still active. Severe turbulence is not expected outside of any convective cells.

Icing

Freezing level: The G-AIRMET Freezing valid at +12hr (Tue 06Z) shows the freezing level at approximately 16,000 ft over the Great Basin/Rocky Mountain region. This places your 9,000 ft cruise altitude well below freezing level — meaning temperatures are above freezing at cruise over the lower-elevation portions of the route. Over the Alaska Range and higher Alaskan terrain, the freezing level will be lower; check Alaska-specific freezing level data before the Alaska portion of the route.

SLD risk: No SLD signal exists anywhere along the planned route at any altitude based on available FIP products.

The G-AIRMET Icing valid at Mon 18Z (+12hr Tue 06Z) shows icing from FZL to FL250 over the northeastern US — well off your route and not relevant. The icing G-AIRMET over northwest Montana (FL130–FL230 at Mon 18Z) is above your cruise altitude.

Bottom line: Icing is not a significant factor for this flight at 9,000 ft. Monitor for localized icing conditions in the Alaska Range crossing segment and in any cloud layers encountered at altitude.

Altitude Strategy

• Best altitude band: 9,000 ft MSL is a reasonable cruise for the CONUS portion — below most icing, above most terrain IFR issues, and within a manageable turbulence band. Over the high Rocky Mountain terrain of central Idaho and Montana (terrain often 6,000–8,000 ft MSL), this gives only 1,000–3,000 ft of clearance. If your personal minimums require 1,500 ft of ceiling buffer above terrain, you are operating near the edge in some segments — consider 10,500–11,500 ft over the highest terrain.
• Worst altitude band: 6,000–8,000 ft MSL over central Idaho and Montana high terrain — in any cloud, you could be in terrain-proximate icing and low clearance simultaneously. Avoid sustained flight in this band through cloud over mountainous terrain.
• Escape option: Over CONUS terrain, climb to 11,500+ ft for terrain clearance if ceilings lower. Over Alaska, the primary escape is turning back or diverting to Talkeetna (PATK) or Anchorage (PANC). Do not press into deteriorating Alaska terrain weather. Identify divert options before entering the Alaskan mountain corridor.

Getting Into 21AK

Estimated arrival: Approximately 02:26Z on July 8 (roughly 747 minutes / 12.5 hours after 14:00Z departure). This is late evening local time in Alaska (approximately 6–7 PM Alaska Daylight Time), well within daylight in summer.

At generation time: No METAR is available for 21AK (Montana Creek). The nearest relevant Alaska PIREP is from BIG (Big Delta, AK) at FL065, which reported moderate turbulence and scattered-to-broken layers at 7,000–8,000 ft MSL. CDV (Cordova) at FL040 reported negative turbulence on approach with broken clouds at 4,000 ft. KTN (Ketchikan) at FL100 reported light occasional moderate turbulence. These PIREPs are geographically scattered across Alaska and do not represent conditions at Talkeetna.

No TAF is available for 21AK. This is the single most significant planning gap for this flight. Montana Creek (21AK) is a private/public airstrip in the Susitna Valley north of Anchorage, in mountainous terrain near Talkeetna. Local weather can be strongly influenced by the Alaska Range to the north and the Talkeetna Mountains to the east.

The WFO AFC aviation discussion noted VFR conditions and light winds at PANC with westerly winds late morning through late evening on Tuesday, with a possible shower near PANC in the afternoon. This is broadly favorable for the Anchorage basin, but Talkeetna weather can diverge significantly from PANC, particularly with orographic effects.

Practical alternates: PATK (Talkeetna Airport) is the nearest identifiable alternate to 21AK. PANC (Anchorage Ted Stevens International) is approximately 60–80 nm south and has full TAF coverage. Strongly recommend pre-briefing alternates and confirming both have forecast conditions meeting your alternate personal minimums (1,000 ft / 3 SM) near your ETA. Confirm the alternate requirement under 14 CFR 91.169 using the destination TAF and your ETA window — no TAF is available for 21AK, which materially affects this determination.

Runway wind estimate: With the synoptic pattern showing light westerly flow dominating Alaska on Tuesday, surface winds at 21AK near arrival time are likely to be light and variable to light westerly, typical for summer evening in the Susitna Valley. However, local drainage flow and valley channeling can produce winds significantly different from the synoptic pattern. This is a high-uncertainty estimate — verify via Alaska FSS and any available Talkeetna ASOS observations before departure.

This is a terrain-localized weather uncertainty problem, not a broad weather system problem. The broad Alaska picture on Tuesday evening looks acceptable; the question is local valley/terrain conditions specific to the Talkeetna area.

Fly or No

MARGINAL GO — with specific conditions that must be met before departure.

This flight is operationally feasible based on available data. KSLC departure is clean at 14Z. The enroute weather over the CONUS is a manageable summer terrain-turbulence scenario, not a systemic weather problem. Icing is not a factor at cruise. No active SIGMETs or AIRMETs conflict with the route during the flight window. The two active CONUS TFRs (Provo UT surface to 400 ft, Sun Valley ID surface to 400 ft) are surface-only and should not conflict with your 9,000 ft cruise altitude — but verify route clearance before taxi.

The MARGINAL GO (rather than GO) is driven entirely by the absence of a TAF or reliable forecast for 21AK in complex mountainous Alaskan terrain, combined with a 12.5-hour estimated flight where conditions can evolve significantly. This is not a hard stop by itself — remote Alaskan operations routinely require pilot judgment in the absence of terminal forecasts — but it demands thorough pre-departure Alaska weather research and a solid alternate plan.

Hard stops:

• Alaska area weather at or near 21AK shows ceilings below 600 ft AGL or visibility below 2 SM with no improvement trend near your ETA — NO-GO.
• Active radar or fresh PIREPs show embedded convection directly on the route corridor through the Idaho/Montana segment that cannot be deviated around — reassess altitude or timing.
• NOTAM 6/3017 (26NM W Yakima, surface to 9,000 ft) has been extended beyond its scheduled 04:00Z expiration — verify before departure and reroute if still active.

Watch items:

• Updated winds aloft showing average headwind component exceeding 40 kt — would significantly impact fuel and potentially trip your headwind personal minimum threshold.
• Any new convective activity developing along the Idaho/Montana corridor during your enroute phase — monitor ATC and onboard weather if equipped.
• Talkeetna-area weather deterioration reported via PIREP or ASOS during the flight — identify decision point for divert to PATK or PANC early in the Alaska portion.

What changes this call

• Alaska area ceilings confirmed below 600 ft AGL or visibility below 2 SM near 21AK at your ETA — changes to NO-GO.
• Updated winds aloft showing headwind component exceeding 40 kt average for a significant portion of the route — reassess fuel and timing.
• Morning radar showing active convective cells within 20 nm of KSLC or directly on route through Idaho at departure time — delay for cell clearance.
• NOTAM 6/3017 (Yakima hazard TFR, 0–9,000 ft) confirmed extended beyond 04:00Z — reroute required to stay clear.

If You Go — Do This

1. Alaska briefing first: Call Alaska FSS (1-800-WX-BRIEF) before departure. Get the latest Talkeetna ASOS observations (PATK), any available PIREPs in the Susitna Valley, and the outlook for the Talkeetna Mountain corridor near 02Z July 8. This single action is the most important pre-departure step.
2. Confirm alternates before departure: Brief PATK (Talkeetna) and PANC (Anchorage) as alternates. Confirm both have forecast conditions meeting your 1,000 ft / 3 SM alternate personal minimums at your ETA. Confirm the 14 CFR 91.169 alternate requirement determination with your actual destination TAF status and ETA.
3. TFR verification before taxi:
   • NOTAM 6/3018 (Provo, UT — active at ETD, surface to 400 ft): verify your departure route avoids the Provo TFR area.
   • NOTAM 6/3019 (Sun Valley, ID — starts at 14:00Z ETD, surface to 400 ft): verify your enroute path avoids the Sun Valley TFR area.
   • NOTAM 6/3017 (26NM W Yakima — scheduled to expire at 04:00Z, about 10 hours before ETD): confirm it has not been extended or amended before taxi. Check tfr.faa.gov or call FSS.
   • NOTAM 6/3022 (15NM E Pendleton, OR — surface to 8,000 ft): confirm your route at 9,000 ft clears this area; avoid any descent below 9,000 ft near Pendleton unless clear of the TFR.
4. Fuel: Distance is 1,867 nm; block time is roughly 747 minutes. With no alternate TAF for 21AK, plan fuel generously. Carry enough to fly to 21AK, miss the approach, divert to PATK or PANC, and hold for 45 minutes minimum.
5. Departure window: 14:00Z is favorable — overnight convection should have cleared, and the daytime heating cycle is still relatively early. Departing significantly later (after 18Z) risks increasing afternoon convective activity over the Idaho/Montana terrain and reduces the safety margin for the Alaska arrival in deteriorating evening weather.
6. Altitude over Idaho/Montana terrain: Consider 10,500–11,500 ft over the central Idaho and southwestern Montana high terrain segments (terrain often 6,000–8,000 ft MSL) to ensure 1,500 ft minimum terrain clearance buffer per your personal minimums. Descend back to 9,000 ft over lower terrain of eastern Washington/Oregon.
7. In-flight: Get updated PIREPs and Alaska weather from ATC or FSS as you approach the Alaska border. Establish your divert decision point — if Alaska area conditions are not confirmed acceptable by the time you reach the vicinity of Anchorage, divert to PANC rather than pressing into the Talkeetna corridor in deteriorating conditions.

Confidence

Medium confidence.

The CONUS departure and enroute portion of this briefing carries relatively high confidence — the TAF at KSLC is clear for the 14Z ETD, the icing products show a benign environment at cruise altitude, and the surface prog and QPF products consistently show no significant weather system affecting the KSLC → Pacific Northwest → southern Alaska corridor during the flight window. The turbulence assessment over Idaho/Montana terrain is supported by GTG products and consistent with the season and synoptic pattern.

Confidence is capped at Medium for three reasons:

• No TAF for 21AK — the most significant data gap. Without a terminal forecast for the destination in mountainous Alaska terrain, any arrival assessment is inherently limited. This single factor prevents a High confidence rating regardless of how clean the rest of the route looks.
• Enroute wind uncertainty — no explicit winds aloft data was provided for this briefing. A 12.5-hour flight at 9,000 ft over 1,867 nm is highly sensitive to wind component changes; a 20 kt error in headwind assumption materially affects fuel and block time.
• Convective evolution near departure — while the 14Z departure timing is favorable, overnight convection near KSLC adds some morning-of uncertainty. The AFD noted low confidence in the wind direction and timing, with storms capable of 30–50 kt outflow winds overnight. This is expected to clear well before 14Z, but requires morning-of confirmation.

Elements that could change the call: an Alaska FSS briefing showing deteriorating conditions in the Talkeetna area near 02Z would shift this to NO-GO. Updated winds aloft showing unexpectedly strong headwinds over the route would require a fuel and timing reassessment. Any extension of the Yakima hazard TFR (NOTAM 6/3017) above 04Z would require routing verification.