8:00 start fri dec 1st no abs

MOUNTAIN WEATHER FORECAST

Time and Day: 0630 Thursday

The Snapshot: Snow begins today and continues through early Sunday morning. A prolonged dry period begins on Sunday and will likely last through most of the first week of December.

The Science

Current Observations:

The temperature is 29^0f , the RH is 92%, the barometer has fallen to 1018mb and the winds are +-5mph and out of the east.  The sky is mostly clear with high clouds beginning to move in.

The Forecast:

A cold front, currently just off the coastal waters, is pushing the next batch of moisture into the region.  Radar has light snow starting to fall along the western slopes and is expected move east and intensifies through the day. 

The cold front is timing out to reach the Cascade Crest sometime late this afternoon or early evening.  As with typical cold frontal passages, the precipitation will shift to light showers and the freezing levels will drop.  Therefore, expect the snow to diminish overnight with a brief dry period starting out the day tomorrow.     

A low-pressure trough, powered by cool NW flow, will swing in tomorrow afternoon bringing with it a steady stream of moisture.  Fairly steady snowfall is expected to continue into early Sunday morning. 

The Long Range:  Sunday marks the start of a prolonged dry period with a strong blocking ridge of high pressure developing over the PNW.        

24hr Precipitation ending at 4am: Today 24hr water: .5” snow: 3-5” Tomorrow’s 24hr water: .75+  snow: 6-8” Trend and Timing: Snow today tapering off tonight.  Snow returns tomorrow afternoon.

24hr temperature ending at 4 am:  Low: 26    High: 32 Freezing level: +- 3500’-3000’ Trend and Timing:    With the aid of east flow, the freezing levels should hold at or just above 3500’ today.  Cooler air begins to arrive early tomorrow morning.

24hr Winds (mph) ending at 4 am: Base: 0-5 E shifting W Ridge Top: 0-10 SSW Trend and Timing: East flow at the surface with southerly flow aloft will be the general wind pattern today.  Once the front passes east of the crest, the winds will shift westerly and strengthen a bit.

jM

8:00 start thur nov 30th no abs

MOUNTAIN WEATHER FORECAST

Time and Day: 0700 Wednesday

The Snapshot: Light snow showers with sun breaks can be expected today.  More snow is expected to arrive tomorrow afternoon and then again on Friday.  Snow will continue into Saturday with a drying trend beginning on Sunday.  

The Science

Current Observations: 

.87” of water produced 11” of snow over the past 24hrs.  The temperature is 30^0f , the RH is 93% and the barometer is 1021mb and rising.  The winds are blowing 10-15mph and out of the west. The cloud deck is broken with spotty showers showing up out to the west. 

The Forecast:

A weak upper-level ridge is drifting over the region this morning, hence the broken clouds and stabilizing atmosphere. There will be a few remnant snow showers from time to time, but for the most part, the next 24-36hrs will be dry.

The leading edge of the next frontal system swings through the mountains tomorrow.  The GFS model has this system arriving late tomorrow afternoon with freezing levels holding near 4000’.  The ECMMF model has it arriving early tomorrow morning with slightly higher temperatures.  – time will tell.  Cooler NW flow develops behind this system with snow likely on Friday and Saturday.

The Long Range:  The weekend will start out snowy as the final trough of this storm cycle moves through.  High pressure is expected to move in on Sunday for a prolonged dry period setting up for early next week.        

24hr Precipitation ending at 4am: Today 24hr water: .10 snow: 0-1 Tomorrow’s 24hr water: .25-.5  snow: 3-5 Trend and Timing: Mostly dry today with some flurries possible. Snow returns late tomorrow afternoon.

24hr temperature ending at 4 am:  Low: 28    High: 32 Freezing level: +-4000’ Trend and Timing:    Temperatures will be fairly consistent (at or near freezing) for the next several days.

24hr Winds (mph) ending at 4 am: Base: 5-10 W Ridge Top: 5-15 W Trend and Timing: Winds will diminish this morning and begin to shift SW tonight.

jM

6:15 start wed Nov 29th no abs

MOUNTAIN WEATHER FORECAST

Time and Day:  0800 Tuesday

The Snapshot:  Increasing snow today, light snow showers with sun breaks tomorrow.   A few inches of snow is expected on Thursday with more active weather expected for the weekend.   

The Science

Current Observations:

 2” of snow fell last night.  The temperature is 30 degrees, the RH is 90% and the barometer is 1014mb and falling and the winds have shifted easterly.  The radar has a band of moderate to heavy moisture just about to enter the mountains.

Forecast:

The cold front, still just offshore, is expected to move east of the mountains sometime this afternoon.  Freezing levels should hold around 4000’ through the day with the exception of a short jump just prior to the arrival of the front. 

Temperatures will fall, the winds will shift westerly and the precipitation will increase this afternoon/evening.  There could be a nice period of heavy snow as good westerly WNW flow sets up.  The snow will shift to showers overnight with a few lingering snow showers and sun breaks expected through the day tomorrow.

The Long Range:  The next frontal system arrives late on Thursday with a few inches of snow expected.  Friday will be interim day between storms with another system expected over the weekend.  The models are all over the board for the weekend's weather, so we will have to wait as they work out their differences.       

24hr Precipitation ending at 4am: Today 24hr water: 1  snow: 8-12 Tomorrow’s 24hr water: .25   snow: 1-3 Trend and Timing: Moderate snow is expected today.  A convergence zone formation will likely provide a few hours of heavy precipitation between 2 pm and 10 pm.   Snow tapers off during the early morning hours.

24hr temperature ending at 4 am:  Low: 28    High:34 Freezing level: +-4000’ Trend and Timing:    Surface temperatures will bump up a few notches this morning and then fall in the wake of the front later today.  Freezing levels will be consistently around 4000’ through tomorrow and likely Thursday as well.

24hr Winds (mph) ending at 4 am: Base: 0-5 E shifting W Ridge Top: 0-10 E shifting W Trend and Timing: Winds will shift westerly later today and strengthen for a few hours tonight.

jM

MOUNTAIN WEATHER FORECAST

Time and Day:  0730 Monday

The Snapshot:  Windy with light snow showers and some clear periods today. Moderate to heavy snow is expected tomorrow.  Wednesday will be an interim day with more systems arriving on Thursday and then again over the weekend.    

The Science

Current Observations:  .57” of water with 3” of snow is reading on the telemetry stake.  The temperature is 29^0f ,  the RH is 87%, the barometer has bumped up a notch to 1010mb’s and ridge top winds are strong and out of the west.  Spotty snow showers are popping up on radar along the western slopes of the mountains.

Cool unstable NW air is beginning to flow with snow showers for mountains likely. However, some weak upper-level ridging could allow some clearing today and tonight.  

The next frontal system is timing out to hit the mountains early tomorrow morning.  This is a nice looking triple point storm with cool NW flow following the leading warm front.  East flow will be a key feature for keeping the precipitation snow for the start of this event.  A quick spike in freezing levels is expected with a short period of mixed rain possible, but it should be short-lived. Steady westerly flow with falling temperatures will fill in tomorrow afternoon for a possible convergence development and thus a period of moderate to heavy snow.   The snow diminished to showers heading into Wednesday morning.

    

The Long Range:  The next storm of interest arrives on Thursday.  This storm has a similar warm-cold dynamic with the potential to add to the snowpack. The good news is that the long range temperatures regime is beginning to fall to its seasonal average – so for the time being, the next few systems should be mostly snow.      

24hr Precipitation ending at 4am: Today 24hr water: lt. 25 snow: 0-2 Tomorrow’s 24hr water: .75-1  snow: 5 -10 Trend and Timing: Light intermittent snow showers today.  Moderate snow begins after 4 am tomorrow.

24hr temperature ending at 4am:  Low:28     High:32 Freezing level: 3500’ - 4500’ Trend and Timing:    Freezing levels will sit around 4000’ through the night.  A quick spike of temperatures will accompany the front tomorrow with freezing levels falling back down to 3500’ late in the day.

24hr Winds (mph) ending at 4am: Base: 5-10 W gusty  shifting E Ridge Top: 10-20 W Trend and Timing: Gusty winds this morning will diminish this afternoon and shift easterly overnight.

jM

MOUNTAIN WEATHER FORECAST

Time and Day:  0800 Sunday

The Snapshot: Rain this morning changing to snow showers tonight.  Light snow can be expected on Monday with heavier snow on Tuesday.

The Science

Current Observations: 2” of snow was squeezed out of .19” of water last night. The temperature is currently 32 degrees, the RH is 96%, the barometer has dropped to 1004mb and the winds are easterly at 5-10mph.   The radar has a band of heavy rain falling in the mountains with a few spots of mixed snow.

The falling barometer is an indicator of the low-pressure trough with an embedded cold front tracking towards the Cascade Mountains.  Freezing levels are expected to drop with the passing of the cold front later today.  The passing of the front will also shift the rain to snow and then diminish the precipitation to intermittent showers through the night.   Cool unstable westerly flow will keep snow showers persistent tomorrow.   

 The Long Range:  A good looking frontal system with cool NW flow will bring moderate to heavy snow on Tuesday.  Wednesday looks relatively quiet with more active weather returning towards the end of the week.     

24hr Precipitation ending at 4am: Today 24hr water: .5-.75” snow: 2-5” Tomorrow’s 24hr water: .5 -75”  snow:4-6” Trend and Timing: Rain is expected for most of the day with snow entering the mix around 4 pm. A weak convergence period could enhance snowfall for a few hours this evening.

24hr temperature ending at 4 am:  Low: 28    High: 36 Freezing level: 6500’- 4000’ Trend and Timing:    Surface temperature will bump up a few degrees this morning and then drop to or below 32 degrees late this afternoon.  Freezing levels are expected to drop to or below 4000’ after 4 pm or so.

24hr Winds (mph) ending at 4 am: Base: 0-5 E shifting W Ridge Top: 5-10 ESE shifting W Trend and Timing: Winds will shift westerly and strengthen with the passing of the front later this afternoon.

jM

MOUNTAIN WEATHER FORECAST

Time and Day:  0900 Saturday

The Snapshot: Light mixed precip this afternoon and evening, moderate to occasionally heavy snow Sunday afternoon/evening.

Current Observations:  Partly cloudy skies and light east winds at Stevens Pass this morning, 30 degrees in the base area and 27 up top. There was a very light trace of new snow yesterday, RH values are in the 90’s and the barometer has been steady for the past 12 hours.

The Science: Clouds in advance of the next weather system to affect Washington are spreading east this morning. A low pressure system off the coast will deepen today, allowing upper level flow from the south to bring a warm front, and then the trailing cold front, across the region. Free air freezing levels will rise during the day Saturday but precipitation shouldn’t begin until the afternoon. Precip may start as light rain or freezing rain at Stevens Pass, but with cool air in place to the east and light east winds indicated thru the night, snow isn’t out of the question either. Either way, precip amounts look pretty light by mid-morning Sunday.

The trailing cold front will swing thru mid day Sunday, bringing a dramatic drop in freezing levels and increase in westerly winds. Precip may start out as rain but should quickly changeover to snow Sunday afternoon. Moderate snow looks to continue into Monday, with a few heavy showers indicated and potential convergence centered over Stevens Pass during the day Monday.

The Long Range:  The trough passes Monday, with zonal flow during the day bringing continued snow showers. Another trough approaches and crosses the area Tuesday, bringing moderate to heavy snow to Stevens Pass. 72 hour snow amounts ending Wednesday afternoon look to be around 18+”. Upper level ridging begins Wednesday with Thursday and Friday looking dry before yet another system approaches Friday afternoon.

24hr Precipitation ending at 4am: Today 24hr water: >.25  snow:0-2” Tomorrow’s 24hr water: .75  snow: 6+” Trend and Timing: Light precip beginning late Saturday afternoon, ending briefly Sunday morning before becoming moderate to heavy Sunday night and Monday.

24hr temperature ending at 4am:  Low: 27    High: 36 Free Air Freezing level: 3500-6500’ Trend and Timing:    Freezing level will rise dramatically during the day Saturday and thru Sunday morning; however, east flow could limit local snow levels to Pass level Sunday morning.

24hr Winds (mph) ending at 4am: Base: E 5-10, Ridge Top: SSE 10-20 Trend and Timing: Easterly flow looks to hang in there thru Sunday morning, before switching to gusty and westerly in the base area and on ridge tops. DV

MOUNTAIN WEATHER FORECAST

Time and Day: 0800 Black Friday

The Snapshot:  We should expect intermittent snow showers with some clear periods today.  Snow changing to rain arrives late tomorrow night.

Not so fun fact: 7.67” of rain fell since Monday with a peak temperature of 48 degrees on Wednesday.       

The Science

Current Observations:  Since 4 am yesterday, 1.44” of water fell with just an inch or two of snow.  The temperature is 32 degrees, the RH is 84%, the barometer is 1013mb and holding steady, the westerly winds are still gusty.  The radar has mostly clear skies over the mountains with spotty showers out to the west.

A weak high pressure ridge developing over the panhandle of Idaho will create a bit of a blocking pattern for the incoming precipitation. A few snow showers will make it through from time to time. The temperatures profile will sit near 32 degrees with freezing levels around 4500’.  

Another warm front is expected to lift up from the south tomorrow for another mixed snow/rain changing to a rain event.  East flow development will keep the moisture as snow for the start; however, the freezing level will likely lift above 5000’ on Sunday morning.  A cold front will swing through Sunday afternoon, dropping temperatures and shifting the rain back to snow showers.  Sound familiar?       

The Long Range:  Monday and Tuesday will be snowy with some potential accumulation.  Then this storm cycle series comes to and end as high pressure begins to build over the region.  So as of now, the last week of November will likely end dry with sunshine and seasonally normal temperatures. 

24hr Precipitation ending at 4am: Today 24hr water:.25  snow: 1-2 Tomorrow’s 24hr water:.25 - .5  snow: 1-4 Trend and Timing: Intermittent snow showers today with tomorrow morning starting out dry.  Snow showers turning to rain showers begin late Saturday night.

24hr temperature ending at 4 am:  Low: 30    High: 34 Freezing level: +-4000’ Trend and Timing:    Freezing levels will hover around 4500’ with some normal daytime warming today.  Cool east flow development will help hold early morning temperatures at or just below freezing.

24hr Winds (mph) ending at 4 am: Base: 0-5 W shifting E Ridge Top: 5-15 W gusty Trend and Timing: The winds will begin to taper off today and then shift easterly tomorrow.

jM

MOUNTAIN WEATHER FORECAST

Time and Day:  0830 Thursday

The Snapshot:  Windy with rain changing to snow today, snow showers can be expected tomorrow with the weekend starting out dry.     

The Science

Current Observations:  1.69” of rain fell over the last 24hrs, the temperature is 43f.  The Rh=97% and the barometer is at 1009mb and falling, the winds are out of the SW at 10-15m ph.

An approaching cold front will push another band of heavy precipitation into the Cascade Mountains today.  Once the front passes east of the crest, the temperature will fall and the heavy precipitation will begin to diminish. Strong westerly flow will also fill in behind the front for a period of convergence zone activity. If the timing of the convergence zone and the cool air works out well, there could be up to 6” of fresh snow on the ground for tomorrow.   

The Long Range:  Saturday will start out mostly dry with another strong southerly push of moisture moving up through the region late Saturday night.   This system appears to have snow changing to rain and then back to snow component – stay tuned as those details become more apparent. The long-range models have a drying trend beginning on Tuesday or Wednesday of next week.

   

24hr Precipitation ending at 4am: Today 24hr water: 1 snow: 4-6 Tomorrow’s 24hr water: .25  snow: 2-4 Trend and Timing: Heavy rain today will slowly shift to snow showers tonight.  Light intermittent snow showers are expected through the day tomorrow.

24hr temperature ending at 4 am:  Low: 32    High: 46 Freezing level: 7500’ – 4000’ Trend and Timing:    Freezing levels will fall today dropping to 5000’ by +- 2 pm and then 4000’ sometime after 7 pm.

24hr Winds (mph) ending at 4 am: Base:  5-10 W Ridge Top: 10-20 W gusty 30+ Trend and Timing:  Winds will strengthen today with strong westerly ridge top winds likely.

jM

MOUNTAIN WEATHER FORECAST

Time and Day:  0800 Wednesday

The Snapshot:  Rain showers today with temperatures reaching into the upper 40’s.  Another batch of heavy precipitation arrives tomorrow with cooling.   

Seattle is expecting record high temperatures to be reached today with flood warnings in effect.   

The Science

Current Observations: 2.63” of rain fell over the last 24hrs, it is 47^0f  at the top of Brooks and currently raining. The Rh is 97%, the barometer has bumped up a notch to 1016mb and the southerly winds are gusting around 10mph.  The bulk of moisture has moved east with moderate rain showers still tracking through the Cascades.

The warm frontal system, that brought us the lovely weather, is now heading into the inter-mountain west.  A record-setting warm air mass with an unstable atmosphere has been left in its wake. This all equates to rain showers and high freezing levels for Stevens Pass.  Another batch of heavy precipitation, out ahead of the approaching cold front, will bring the next round of heavy rain tomorrow. 

The good news: Cooler air associated with this slow moving cold front, is expected to reach the North Central Cascades tomorrow. The freezing levels should begin to fall tomorrow afternoon and drop to or below 4000’ sometime early Friday morning.  We should see some fresh snow beginning to accumulate Friday and Saturday.   

The Long Range:  The PNW storm machine will continue to pound the region through the weekend.  Freezing levels will bounce between 3500’ and 5000’ with several pulses of moisture expected.      

24hr Precipitation ending at 4am: Today 24hr water: .5-.75 snow: 0 Tomorrow’s 24hr water: 1 snow: 2-6 Trend and Timing: Rain showers today.  Moderate to heavy rain starts the day tomorrow and slowly changes to snow.

24hr temperature ending at 4 am:  Low: 38    High: 48 Freezing level: 8- 6000’. Trend and Timing:    Surface temperatures could briefly hit 500f today.  Freezing levels will start to fall tomorrow and drop to or below 4000’ sometime early Friday morning.

24hr Winds (mph) ending at 4 am: Base: 0-5 SSE Ridge Top: 5-15 SW Trend and Timing: This southerly flow pattern will begin to shift westerly and strengthen tomorrow afternoon.

jM