683 FXAK68 PAFC 101220 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 420 AM AKDT Wed Oct 10 2018 .ANALYSIS AND UPPER LEVELS... A storm force surface low is in the process of crossing the Alaska Peninsula early this morning. Ahead of and to the north of the low, east to northeasterly winds are increasing across much of Southwest Alaska and coastal Southcentral particularly through channeled terrain and downwind of gaps and passes. To the south and west of the low the ASCAT scatterometer indicates storm force west to northwesterly winds with strongest winds to the south of the tip of the bent back occlusion. Along the eastern portions of the Alaska Peninsula and in the greater Bristol Bay area there have been a couple isolated thunderstorms embedded in the precipitation along the back edge of the front. To the east of the low, the ridge aloft has shifted east over the Southeast Alaska Panhandle and Yukon Territory, while to the west a multi-center upper level low stretches across the Bering. && .MODEL DISCUSSION... Models are in good synoptic agreement regarding the current low and the next two troughs which follow it. By Thursday night and Friday, some differences start creeping into the model runs regarding which features become closed triple point surface lows as opposed to remaining open troughs however the timing of the waves does remains similar between models. && .AVIATION... PANC...Wind shear will become an increasing concern this morning as east to southeasterly gap winds strengthen through Turnagain Arm. Northerly down inlet surface flow however, should keep these strong winds from surfacing until after the front moves through midday. Following that expect strong, gusty southeasterly winds turning more southerly through the afternoon and early evening. && .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)... The front stretching across the Kenai Peninsula and northern Gulf will move rapidly northward today, pushing across the Alaska Range this afternoon. The main surface low associated with this front will move from near King Salmon this morning to the Yukon Delta this afternoon. A triple point surface low forming on the front near Kamishak bay this morning will race up Cook Inlet to near Denali this afternoon, though this feature is somewhat obscured by the terrain in the model plots. The result of all of this will be windy conditions over most of the area. Ahead of and with the front, the winds will be easterly, and favor gaps in the terrain. Behind the front and triple point low, the winds will be southerly and more widespread with the strong pressure rises as surface high pressure follows the front. Rain will also be more widespread with and just behind the front, as the flow aloft becomes southwesterly and downsloping ends. Winds will diminish through tonight into Thursday as the pressure gradient relaxes. Some showers will continue as the southwesterly flow aloft remains. Another front will approach from the southwest Thursday and Thursday night. This front is not as strong as the Wednesday front. The low level flow with this front will be more easterly, and thus favor gaps in the terrain. Some downslope drying will occur, but with plenty of moisture and fast upper level flow, some showers are still expected. && .SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)... (Today through Friday) The much-talked about remnants of the former typhoon are working across the AKPEN now, spreading widespread light to moderate rainfall across almost all of the region, with even a few lightning strikes from the AKPEN to north of King Salmon. This general theme of wet weather looks to continue over the next few days, as this system lifts north before retrograding towards Saint Matthews Island, with another developing low moving from the central Aleutians into the Bristol Bay region for Thursday into Friday. The combination of cyclonic flow around the first storm and a renewed moisture surge with the next low will maintain a chance of rainfall across all of southwest Alaska through the period. && .SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3)... (Today through Friday) The remnants of the former typhoon are moving ashore along the peninsula now, with sustained storm force winds expected to continue through late morning for locations near Shelikof Strait, before gradually subsiding this afternoon. Sustained gales will continue for Bristol Bay on the bay side of the ex-tropical system, with widespread rainfall continuing from coastal locations of the AKPEN north across the eastern Bering Sea. Farther west, sustained low-end gales are expected on the Bering side of the central Aleutians, as disturbances rotating around the Bering low help mix down some stronger winds aloft. Otherwise, precipitation will be more showery compared to locations further east. Heading into Thursday and Friday, look for winds to be at or below small craft conditions with no significant seas expected, and showers continuing. && .LONG TERM FORECAST (Days 3 through 7)... The mid to long term begins Friday with the models in overall agreement with a low over the eastern to northern Bering Sea and a ridge of high pressure extending into southeast Alaska. The models have also come into good agreement with respect to the next storm on tap for the western Bering Sea, moving into the western Aleutians late Friday. This storm is taking a track along the Aleutian chain to the western Alaska Peninsula through Monday morning. This is where the models then begin to show more significant differences in the solutions for it. At that point the ensemble and WPC solutions will be used. The current forecast have a slightly faster track for the low along the Aleutians, and we will nudge toward this solution, primarily resulting in adjusting the wind direction to better align with the WPC solution. && .AFC WATCHES/WARNINGS/ADVISORIES... PUBLIC...None. MARINE...Gale 119 120 125 130 131 136 137 139 140 141 150 155 160. Storm 132 138. && $$ SYNOPSIS AND MODEL DISCUSSION...JER SOUTHCENTRAL ALASKA...BL SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PD LONG TERM...SA