powderfreak
New member
Wow. What an October storm we have on our hands. Regardless of whether or not you recieve rain, snow, sleet, wind, or all of them, this should be a memorable storm.
Bottom Line Forecast by region (I did not include any wording such as "heavy at times" or "heavy snow" or "heavy rain" as it is implied that precipitation will be heavy at times throughout until ending showery in nature...windy conditions should also be assumed throughout):
Central Apps (WV,PA) and southern tier of NY between Elmira and Jamestown: Rain changing to wet snow tonight above 1,500ft with 2-5" accumulating by morning above 2,000ft and 1-3" above 1,500ft. Wet snow continues above 1,500ft but dropping to 1,000ft throughout the day...mostly rain below...tapering off to snow showers by evening. Total Accumulations of 4-8" above 2,000ft with 2-4" above 1,000ft.
Catskills: Snow above 2,000ft changing to rain everywhere overnight. Rain continues tomorrow changing to snow above 2,000ft by noon and then to 1,500ft by 6pm. Snow level tomorrow night drops to 1,000ft with rain/snow mix in the valleys. Snow and rain showers quickly end on Wednesday morning with total accumulations of 1-3" above 1,000ft...3-5" above 1,500ft...and 6-9" above 2,000ft.
Berkshires: Rain tonight and tomorrow...changing to snow above 1,000ft tomorrow night and tapering to snow showers Wednesday morning. Total accumulations of 1-3" above 1,000ft with 3-5" above 2,000ft.
Adirondacks: Rain/Snow mix above 2,000ft tonight briefly changing to all rain around daybreak. Rain quickly changes back to snow above 2,000ft and then the snow level drops to 1,500ft around noon. Snow in the afternoon dropping to the valley floors by evening. Snow then continues to fall Tuesday night and tapers off on Wednesday with occasional backlash snow showers throughout the day. Total accumulations of 3-6" above 1,000ft with 6-12" above 1,500ft. Some of the highest inhabited areas of the Adirondacks could see 12-14".
Green Mountains From Killington northward: Snow possibly starting above 2,000ft before changing to rain quickly. Rain tomorrow morning changing to snow above 3,000ft around noon with snow levels dropping to 2,000ft by 6pm and 1,000ft by 12am Wed. Snow continues overnight above 1,000ft with rain mixed with snow below 1K ft. Precipitation ends as snow showers everywhere on Wednesday with upslope favored areas seeing persistent snow showers till Wednesday night. Total Accumulations: 6-12" above 2,000ft with 3-6" above 1,500ft and a coating to 3" below 1,500ft.
Green Mountains south of Killington: Snow and rain above 2,000ft changing to all rain overnight. Rain changing to snow above 2,000ft early tomorrow night (9pm) then down to 1000ft overnight. Snow showers all elevations on Wednesday with total accumulations of 4-8" above 2,000ft and 2-4" above 1,000ft...with a coating to 2" below 1,000ft.
White Mountains: Rain beginning by tomorrow morning. Rain changing to snow above 3,000ft in the early afternoon with snow levels falling to 2,000ft by 9pm. Snow continues overnight above 2,000ft and snow levels falling to 1,000ft early at night in the north and by morning in the south. Snow ends by noon on Wednesday with 4-8" above 2,000ft and 2-4" above 1,000ft...with a coating to 2" below 1,000ft.
My Discussion:
Wilma has already done her damage in Florida and is racing off to the northeast between 30 and 40mph. While the airmass behind the storm is not impressively cold aloft, there could be some areas of frost tomorrow morning as far south as north-central Florida. It is currently snowing in parts of the central Appalachians (mostly West Virgina but some snow was reported in Garret County, Maryland as well as extreme NE Kentucky) as well as the highest terrain of PA and the southern tier of NY. It appears as though 2,000ft has been the level where heavy rain turns to snow across western NY and PA at this time. The upper level low appears to be crossing WV and the 500mb trough is digging strongly into the Ohio Valley. The IR satellite view shows that there is one last peice of energy digging southward across Lake Michigan on the western side of the trough. Current 300mb upper air analysis also shows a very impressive jet streak up the east coast from NC to ME which will provide ample upper air divergence in the right rear exit region over the northeast...this region is currently located across portions of the mid-Atlantic but as the coastal low forms, the jet streak will be pushed northwest allowing the heavy precip down south to move into upstate NY, VT, NH, and ME.
Strong pressure falls have been noted just off the NC coast indicating the formation of the coastal low as the Ohio Valley low weakens. Wilma will remain her own storm for the time being but eventually the upper level trough will absorb her energy and that will turn the coastal low on a negative tilt. The models differ significantly with regards to the exact track of the surface low and the upper level low. This is where the forecast becomes very difficult because a slight change in track will significantly alter already marginal temperature profiles.
The NAM actually takes the low on such a negative tilt that it enters the lower Hudson River Valley and traverses southern New England after that. The GFS is much further east with a track that stays just off shore near Cape Cod. Both have been very bullish on their projected tracks, however, the 00z NAM continues this trend of the low going inland...it also has some support from the RUC to some extent and the NGM for what little that's worth. A more inland surface low track would be caused by a further west upper level low track which cannot happen if VT and NH want to see heavy snow. The upper level low needs to stay to the southeast of the North Country in order to see snow but the NAM tracks it pretty much over the area resulting in a dryslot and less QPF as snow. GFS has been staying off-shore and still shows a significant snowfall for the Adirondacks and Green Mountains.
What I believe will happen is the surface low will track between the two models as I think the NAM has some weight to it, but a true on-shore track doesn't make sense with a baroclinic zone just off-shore. I believe it will track from the NC coast to Maine crossing over Cape Cod in the process.
850mb temperatures are starting out at -2 across most of the north country but rising to 0 or even slightly positive tomorrow morning with warm air advection from winds out of the SE. Areas such as the southern tier of NY state from BGM to Buffalo and the higher elevations of western and central PA will not have this warm air advection so as they are changing to snow as I write, they should remain snow. Tomorrow night, as the low passes, temperatures aloft will fall from the NW to SE resulting in snow levels falling, possibly to the valley floors across NY and VT by Wednesday morning. It appears as though the rain/snow line will be around 2,000ft elevation at first while slowly dropping or mixing to the 1500 or 1000ft elevations...from there, I expect most regions to switch to snow below 1000ft at around the same time as cold enough air seems to work its way in quickly as the storm wraps up. Proximity to colder air, higher elevation, and a further west track than earlier anticipated should lead to the highest snowfall totals occuring in the Adirondacks...and possibly another snowfall maximum down in NY's southern tier along with the higher elevations of north-central PA.
Along with all of this, high wind will be a factor. Heavy rain and wind can cause problems with loose soil, but heavy wet snow and wind will cause serious problems. Expect power outages in areas that recieve more than 4" of wet snow.
-Scott
Bottom Line Forecast by region (I did not include any wording such as "heavy at times" or "heavy snow" or "heavy rain" as it is implied that precipitation will be heavy at times throughout until ending showery in nature...windy conditions should also be assumed throughout):
Central Apps (WV,PA) and southern tier of NY between Elmira and Jamestown: Rain changing to wet snow tonight above 1,500ft with 2-5" accumulating by morning above 2,000ft and 1-3" above 1,500ft. Wet snow continues above 1,500ft but dropping to 1,000ft throughout the day...mostly rain below...tapering off to snow showers by evening. Total Accumulations of 4-8" above 2,000ft with 2-4" above 1,000ft.
Catskills: Snow above 2,000ft changing to rain everywhere overnight. Rain continues tomorrow changing to snow above 2,000ft by noon and then to 1,500ft by 6pm. Snow level tomorrow night drops to 1,000ft with rain/snow mix in the valleys. Snow and rain showers quickly end on Wednesday morning with total accumulations of 1-3" above 1,000ft...3-5" above 1,500ft...and 6-9" above 2,000ft.
Berkshires: Rain tonight and tomorrow...changing to snow above 1,000ft tomorrow night and tapering to snow showers Wednesday morning. Total accumulations of 1-3" above 1,000ft with 3-5" above 2,000ft.
Adirondacks: Rain/Snow mix above 2,000ft tonight briefly changing to all rain around daybreak. Rain quickly changes back to snow above 2,000ft and then the snow level drops to 1,500ft around noon. Snow in the afternoon dropping to the valley floors by evening. Snow then continues to fall Tuesday night and tapers off on Wednesday with occasional backlash snow showers throughout the day. Total accumulations of 3-6" above 1,000ft with 6-12" above 1,500ft. Some of the highest inhabited areas of the Adirondacks could see 12-14".
Green Mountains From Killington northward: Snow possibly starting above 2,000ft before changing to rain quickly. Rain tomorrow morning changing to snow above 3,000ft around noon with snow levels dropping to 2,000ft by 6pm and 1,000ft by 12am Wed. Snow continues overnight above 1,000ft with rain mixed with snow below 1K ft. Precipitation ends as snow showers everywhere on Wednesday with upslope favored areas seeing persistent snow showers till Wednesday night. Total Accumulations: 6-12" above 2,000ft with 3-6" above 1,500ft and a coating to 3" below 1,500ft.
Green Mountains south of Killington: Snow and rain above 2,000ft changing to all rain overnight. Rain changing to snow above 2,000ft early tomorrow night (9pm) then down to 1000ft overnight. Snow showers all elevations on Wednesday with total accumulations of 4-8" above 2,000ft and 2-4" above 1,000ft...with a coating to 2" below 1,000ft.
White Mountains: Rain beginning by tomorrow morning. Rain changing to snow above 3,000ft in the early afternoon with snow levels falling to 2,000ft by 9pm. Snow continues overnight above 2,000ft and snow levels falling to 1,000ft early at night in the north and by morning in the south. Snow ends by noon on Wednesday with 4-8" above 2,000ft and 2-4" above 1,000ft...with a coating to 2" below 1,000ft.
My Discussion:
Wilma has already done her damage in Florida and is racing off to the northeast between 30 and 40mph. While the airmass behind the storm is not impressively cold aloft, there could be some areas of frost tomorrow morning as far south as north-central Florida. It is currently snowing in parts of the central Appalachians (mostly West Virgina but some snow was reported in Garret County, Maryland as well as extreme NE Kentucky) as well as the highest terrain of PA and the southern tier of NY. It appears as though 2,000ft has been the level where heavy rain turns to snow across western NY and PA at this time. The upper level low appears to be crossing WV and the 500mb trough is digging strongly into the Ohio Valley. The IR satellite view shows that there is one last peice of energy digging southward across Lake Michigan on the western side of the trough. Current 300mb upper air analysis also shows a very impressive jet streak up the east coast from NC to ME which will provide ample upper air divergence in the right rear exit region over the northeast...this region is currently located across portions of the mid-Atlantic but as the coastal low forms, the jet streak will be pushed northwest allowing the heavy precip down south to move into upstate NY, VT, NH, and ME.
Strong pressure falls have been noted just off the NC coast indicating the formation of the coastal low as the Ohio Valley low weakens. Wilma will remain her own storm for the time being but eventually the upper level trough will absorb her energy and that will turn the coastal low on a negative tilt. The models differ significantly with regards to the exact track of the surface low and the upper level low. This is where the forecast becomes very difficult because a slight change in track will significantly alter already marginal temperature profiles.
The NAM actually takes the low on such a negative tilt that it enters the lower Hudson River Valley and traverses southern New England after that. The GFS is much further east with a track that stays just off shore near Cape Cod. Both have been very bullish on their projected tracks, however, the 00z NAM continues this trend of the low going inland...it also has some support from the RUC to some extent and the NGM for what little that's worth. A more inland surface low track would be caused by a further west upper level low track which cannot happen if VT and NH want to see heavy snow. The upper level low needs to stay to the southeast of the North Country in order to see snow but the NAM tracks it pretty much over the area resulting in a dryslot and less QPF as snow. GFS has been staying off-shore and still shows a significant snowfall for the Adirondacks and Green Mountains.
What I believe will happen is the surface low will track between the two models as I think the NAM has some weight to it, but a true on-shore track doesn't make sense with a baroclinic zone just off-shore. I believe it will track from the NC coast to Maine crossing over Cape Cod in the process.
850mb temperatures are starting out at -2 across most of the north country but rising to 0 or even slightly positive tomorrow morning with warm air advection from winds out of the SE. Areas such as the southern tier of NY state from BGM to Buffalo and the higher elevations of western and central PA will not have this warm air advection so as they are changing to snow as I write, they should remain snow. Tomorrow night, as the low passes, temperatures aloft will fall from the NW to SE resulting in snow levels falling, possibly to the valley floors across NY and VT by Wednesday morning. It appears as though the rain/snow line will be around 2,000ft elevation at first while slowly dropping or mixing to the 1500 or 1000ft elevations...from there, I expect most regions to switch to snow below 1000ft at around the same time as cold enough air seems to work its way in quickly as the storm wraps up. Proximity to colder air, higher elevation, and a further west track than earlier anticipated should lead to the highest snowfall totals occuring in the Adirondacks...and possibly another snowfall maximum down in NY's southern tier along with the higher elevations of north-central PA.
Along with all of this, high wind will be a factor. Heavy rain and wind can cause problems with loose soil, but heavy wet snow and wind will cause serious problems. Expect power outages in areas that recieve more than 4" of wet snow.
-Scott
