Jump to content
  • Member Statistics

    17,606
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

West Coast storm attack 2017


janetjanet998

Recommended Posts

an endless parade of storms on the way 

WPC has up to 25 inches of precip in the CA mountains next 7 days

first storm to prime the area today...

 

DAY 1


 

NORTHERN TO CENTRAL CALIFORNIA    

 

THE CLOSED LOW OFF THE WASHINGTON/OREGON COAST EXPECTED TO MOVE   LITTLE DURING THE UPCOMING DAY 1 TIME PERIOD. A SURGE OF ABOVE   AVERAGE PW VALUES---2.0 TO 2.5 STANDARD DEVIATIONS ABOVE THE   MEAN---EXPECTED TO PUSH EAST NORTHEASTWARD IN THE WEST SOUTHWEST   MID TO UPPER LEVEL FLOW TO THE SOUTH OF THIS CLOSED   LOW---INITIATING AN ATMOSPHERIC RIVER EVENT THIS PERIOD FOR   NORTHERN TO CENTRAL CALIFORNIA. THIS WILL SUPPORT INCREASING   HEAVY PRECIPITATION FOR MOST OF CENTRAL TO NORTHERN CALIFORNIA DAY   1---WITH 1 TO 3 INCH AMOUNTS IN THE NORTHERN TO CENTRAL CALIFORNIA   COAST RANGE---WHILE 3 TO 5 INCH LIQUID EQUIVALENTS ARE EXPECTED   THROUGH THE SIERRA. VERY HEAVY SNOWS LIKELY IN THE SIERRA WITH 1   TO 3 FOOT AMOUNTS DAY 1 AND ADDITIONAL VERY HEAVY TOTALS LIKELY   DAY 2.


 

AYS 2 AND 3...  
   
..CA INTO THE CENTRAL GREAT BASIN/ROCKIES  
  
AN EXTREMELY WET ANOMALOUS PATTERN IS BEGINNING TO TAKE SHAPE FOR  
CA AND SPREADING DOWNSTREAM INTO THE CENTRAL GREAT BASIN AND  
ROCKIES. AN IMPRESSIVE CLOSED POLAR/ARCTIC UPPER LOW NEAR COASTAL  
WA/OR WILL SLOWLY PRESS SOUTH AND EAST ON WED BEFORE FLATTENING OR  
SHEARING-OUT SOME TO REACH THE FOUR CORNERS STATES BY FRI MORNING.  
MEANWHILE UPSTREAM OVER THE EAST CENTRAL PAC... AN EXTREMELY  
DYNAMIC CLOSED LOW IS PRESENT WITH A COPIOUS AMOUNT OF MOISTURE  
AVAILABLE. AS THE FEATURE NEAR WA/OR PRESSES SOUTH ON WED... A  
PIECE OF UPPER DYNAMICS FROM THIS PAC SYSTEM ADVECTS DOWNSTREAM  
TOWARD CA. GFS AND ECMWF 850-700MB STANDARDIZED MOISTURE FLUX  
ANOMALIES WILL REACH 4 TO 5 TIMES ABOVE AVG ON WED WITHIN THIS  
MOISTURE WRLY FLOW OF PAC AND SUBTROPICAL MOISTURE. THE RESULT  
WILL BE VERY IMPRESSIVE RAINFALL AND SNOWFALL AMOUNTS FOR CA AND  
SPREADING DOWNSTREAM INTO THE CENTRAL GREAT BASIN AND FOUR CORNERS  
REGION. WPC FOLLOWED A BLEND OF THE GFS/ECMWF THROUGHOUT THE FCST  
FOR QPF... SUGGESTING 2 TO 4 INCHES ALONG COASTAL RANGES FROM  
SOUTH OF SFO TO SBA AND 3 TO 6 INCHES WITH LOCALLY HIGHER AMOUNTS  
ALONG THE ENTIRE SIERRA... WHERE MUCH OF THIS WILL BE IN THE FORM  
OF HEAVY SNOW ACCUMULATIONS. THE MOIST FLOW WILL ADVANCE  
DOWNSTREAM WITH THE SHORT WAVE DIGGING INTO THE FOUR CORNERS  
REGION ON THURS AND EXPECT HEAVY QPF FROM THE WASATCH TO THE CO  
ROCKIES AND SAN JUANS.   

Link to comment
Share on other sites

  • Replies 102
  • Created
  • Last Reply

 

SFO

OVERALL, RAINFALL WILL BE DECREASING NORTH TO SOUTH LATER TODAY  
AND INTO THE EVENING HOURS. HOWEVER, THE BREAK WILL BE BRIEF AS A  
WEAK SECONDARY WAVE THEN MOVES ACROSS TONIGHT INTO THURSDAY.  
MODELS ARE IN FAIRLY POOR AGREEMENT ALTHOUGH THE NAM CONTINUES TO  
INDICATE THE POTENTIAL FOR ANOTHER ROUND OF MODERATE TO EVEN  
HEAVY RAINFALL IN THE SANTA LUCIAS. THAT RAINFALL SHOULD BE  
THROUGH BY MID-AFTERNOON WITH CLEARING CONDITIONS LIKELY BY  
THURSDAY NIGHT. THIS WILL LEAD TO A SUBSTANTIAL DROP IN  
TEMPERATURES FOR FRIDAY MORNING WITH MANY LOWS GETTING INTO THE  
30S. FREEZING CONDITIONS ARE POSSIBLE OVER PORTIONS OF THE NORTH  
BAY. FRIDAY WILL ALSO BE THE ONLY DRY DAY FOR THE WEEK.  
 
STARTING ON SATURDAY ANOTHER ATMOSPHERIC RIVER SETUP OF MUCH  
GREATER CONCERN WILL BRING WIDESPREAD RAINFALL TO OUR REGION.  
MODELS HAVE BEEN HIGHLIGHTING THE WEEKEND INTO MONDAY FOR MULTIPLE  
DAYS NOW AS AN AREA OF CONCERN. PW VALUES IN EXCESS OF 1.30" ALONG  
WITH IVT VALUES POSSIBLY ABOVE AN INCREDIBLE 1000 KG/M/S WILL BE  
ALONG OUR COAST FOR AROUND 48 HOURS. DURING THAT TIME MODERATE TO  
HEAVY RAIN WILL BLANKET OUR REGION WITH VERY HIGH RAINFALL AMOUNTS  
LIKELY. EARLY GUIDANCE INDICATES THE POTENTIAL FOR MANY URBAN AREA  
PICKING UP 2 TO 5 INCHES WITH MUCH HIGHER AMOUNTS LIKELY FOR LOCAL  
HILLS AND MOUNTAINS. SIMILAR TO LAST NIGHT, GUSTY SOUTH TO  
SOUTHEAST WINDS CAN ALSO BE EXPECTED. 924 MB SPEEDS ARE FORECAST  
TO AGAIN BE AROUND 50 KTS.  
 
UNLESS THERE IS A MAJOR DEVIATION FROM THE CURRENT SUITE OF  
MODELS, WE WILL LIKELY HAVE MANY HYDRO ISSUES. IN FACT, "IF THE  
FORECAST ABOVE IS REALIZED, THE HYDROLOGIC IMPACTS OF SUCH A  
WEATHER PATTERN ARE EXPECTED TO BE NUMEROUS AND WIDESPREAD THROUGH  
MANY SECTORS OF THE SERVICE AREA." PLEASE SEE THE DETAILED  
HYDROLOGIC OUTLOOK (SFOESFMTR) FOR MORE INFORMATION.  
 
FINALLY, AFTER THE WEEKEND STORM, THERE ARE SEVERAL MORE SYSTEMS  
LINED UP GOING THROUGH THE END OF NEXT WEEK AND POTENTIALLY  
BEYOND. NEEDLESS TO SAY, RAINFALL TOTALS BY THE MIDDLE OF JANUARY  
ARE GOING TO BE QUITE IMPRESSIVE.

Link to comment
Share on other sites

one more wave for the "moderate primer" then a break before the monster this weekend, it was a wet december and reservoirs are rather full

 

just for fun....

9 day precip totals in the 1997 flood

SAC 3.71

Redding 5.29

Blue Canyon 36.34 (22 inches in 72 hours)

 

 

info on 1997 flood

 

http://www.cnrfc.noaa.gov/storm_summaries/jan1997storms.php

 

Link to comment
Share on other sites

1 minute ago, janetjanet998 said:

 

 

just for fun....

9 day precip totals in the 1997 flood

SAC 3.71

Redding 5.29

Blue Canyon 36.34 (22 inches in 72 hours)

 

 

 

 

2 day totals ending at noon for this event

SAC  .26 + .87 = 1.13

Redding  .16 + 1.89 = 2.05

Blue Canyon 1.27 + 3.02 = 4.29

Link to comment
Share on other sites

237 PM PST WED JAN 4 2017  
  
...FLOOD WATCH IN EFFECT FROM SATURDAY AFTERNOON THROUGH MONDAY  
AFTERNOON...  
  
THE NATIONAL WEATHER SERVICE IN SACRAMENTO HAS ISSUED A  
  
* FLOOD WATCH FOR A PORTION OF NORTHERN CALIFORNIA...INCLUDING   
  THE FOLLOWING BURNEY BASIN .../ EASTERN SHASTA COUNTY...   
  CARQUINEZ STRAIT AND DELTA...CENTRAL SACRAMENTO VALLEY...CLEAR   
  LAKE/SOUTHERN LAKE COUNTY...MOTHERLODE...MOUNTAINS   
  SOUTHWESTERN SHASTA COUNTY TO NORTHERN LAKE COUNTY...NORTHEAST   
  FOOTHILLS/SACRAMENTO VALLEY...NORTHERN SACRAMENTO VALLEY...   
  NORTHERN SAN JOAQUIN VALLEY...SHASTA LAKE AREA / NORTHERN   
  SHASTA COUNTY...SOUTHERN SACRAMENTO VALLEY...WEST SLOPE   
  NORTHERN SIERRA NEVADA AND WESTERN PLUMAS COUNTY/LASSEN PARK.   
  
* AN ATMOSPHERIC RIVER WILL LIKELY PRODUCE A PROLONGED PERIOD OF  
  OCCASIONALLY INTENSE RAINFALL WITH SNOW LEVELS ABOVE 7000 TO   
  8000 FEET LATE SATURDAY THROUGH MONDAY. AMOUNTS NOT SEEN SINCE   
  DECEMBER 2005.  

  
* COASTAL RANGE, SHASTA COUNTY MOUNTAINS, AND CENTRAL VALLEY: A  
  TOTAL OF 5 TO 8 INCHES OF ADDITIONAL RAINFALL WILL BE POSSIBLE  
  OVER HIGHER TERRAIN WHILE THE VALLEY IS EXPECTED TO RECEIVE 2 TO  
  5 INCHES. THE GREATEST VALLEY AMOUNTS MAY BE ACROSS THE SOUTHERN  
  SACRAMENTO AND NORTHERN SAN JOAQUIN VALLEYS.  
  
* WEST SLOPE SIERRA NEVADA: A TOTAL OF 8 TO 15 INCHES OF  
  ADDITIONAL RAINFALL WILL BE POSSIBLE. 

Link to comment
Share on other sites

SAC 

   
DISCUSSION (TONIGHT THROUGH MONDAY)  
  
A PACIFIC FRONTAL SYSTEM CONTINUES OVER NORTHWEST CALIFORNIA THIS  
AFTERNOON AND EVENING WITH PRECIPITATION GENERALLY SOUTHWARD OF  
THE SUTTER BUTTES. THE FRONT HAS STAGNATED TODAY WITH MUCH OF OUR  
FORECAST AREA WITHIN THE WARM SECTOR AHEAD OF THE FRONT WITH SNOW  
LEVELS ABOVE 5000 TO 6000 FEET OVER THE SIERRA. SHOWERS SHOULD BE  
DIMINISHING OVER THE VALLEY TONIGHT AND LINGER OVER THE SIERRA   
INTO THURSDAY. UPPER LEVEL RIDGING AND NORTHERLY FLOW SHOULD   
BRING AN END OF PRECIPITATION OVER NORCAL ON THURSDAY NIGHT AND   
FRIDAY. A COOL AIRMASS OVER THE REGION WILL KEEP DAYTIME HIGHS   
FROM WARMING MUCH FRIDAY.   
  
THE NEXT WAVE WITH ATMOSPHERIC RIVER MOISTURE BREAKS DOWN THE   
TRANSITORY RIDGE QUICKLY LATE FRIDAY EVENING. AN UPPER LOW SITS   
OUT OVER THE EASTERN PACIFIC WITH WEST-SOUTHWEST FLOW OVER REGION  
THAT IS FORECAST TO BRING VERY SIGNIFICANT RAINFALL TO THE AREA   
SATURDAY THROUGH MONDAY. MODELS HAVE THE INTEGRATED WATER   
TRANSPORT CENTERED OVER THE NORTHERN AND CENTRAL SIERRA, SO A PLETHORA  
OF RAINFALL COULD FALL OVER THE SIERRA, POSSIBLY 10 TO 15 INCHES   
OVER THE SIERRA AND 3 TO 5 INCHES IN THE VALLEY.   
  
WITH THESE NUMBERS IN THE SIERRA/FOOTHILLS, MODELS SHOW RETURN  
RAINFALL INTERVALS OF EVERY 5 TO 10 YEARS NORTHWARD OF I-80 AND   
10 TO 25 YEAR RETURNS SOUTHWARD. THIS ADDITIONAL RAIN ON TOP OF  
ALREADY SATURATED SOIL WILL LIKELY CAUSE SOME RIVER, STREAM,   
CREEK AND STREET FLOODING. NON-REGULATED RIVERS (NON-DAMMED) LIKE  
THE COSUMNES RIVER, THE AMERICAN RIVER ABOVE FOLSOM DAM,AND OTHER  
SIERRA RIVERS SOUTH OF I-80 HAVE NOT SEEN POTENTIAL FLOODING OF   
THIS NATURE SINCE DECEMBER 2005. THIS THREE DAY EXPECTED SIERRA   
RAINFALL AMOUNTS ARE APPROXIMATELY TWICE THE JANUARY MONTHLY   
AVERAGE.    JCLAPP  
  
   
  
  
.EXTENDED DISCUSSION (MONDAY NIGHT THROUGH WEDNESDAY)   
A BRIEF BREAK IN THE RAIN MON NITE INTO TUE MORNING AS THE WET   
WEEKEND STORM AND ITS ASSOCIATED TPW PLUME MOVE THROUGH NORCAL.   
BY TUE AFTERNOON AND EVENING, ANOTHER LAND-FALLING TPW PLUME HITS   
NORCAL AS ANOTHER SURGE OF ENERGY AND AN UPPER TROF ROTATE EWD   
AROUND THE UPPER LOW OVER THE NERN PAC. THE GEFS ENSEMBLE MEAN   
FROM 1/4/17 00Z SUGGESTS THIS PLUME WON'T BE QUITE AS MOIST AS   
THE WEEKEND PLUME, ALTHOUGH THE DAY OPERATIONAL RUN IS RELATIVELY   
SIMILAR TO ITS PREDECESSOR.  

Link to comment
Share on other sites

.CA AND PACIFIC NORTHWEST  
  
THE NEXT SURGE OF MOISTURE AND INCREASED SYNOPTIC SUPPORT WILL  
MOVE INTO THE WEST COAST SATURDAY INTO SATURDAY NIGHT. THIS IS  
SETTING UP TO BE AN IMPRESSIVE EVENT...WITH BOTH INTEGRATED  
MOISTURE TRANSPORT AND PRECIPITABLE WATER VALUES APPROACHING  
CLIMATOLOGICAL RECORD VALUES ACROSS CALIFORNIA BY LATER SATURDAY.  
LOW LEVEL WIND FIELDS ALSO WILL APPROACH AND/OR EXCEED THE 99TH  
PERCENTILE WITH THIS SYSTEM HELPING ENHANCE UPSLOPE PRECIPITATION  
EFFICIENCY. THUS EXPECT TO SEE IMPRESSIVE QPF AMOUNTS WITH THIS  
SYSTEM...WHICH WILL EXTEND BEYOND THE DAY 3 PERIOD AS WELL. THIS  
RAINFALL COMBINED WITH THE HEAVY ANTECEDENT RAINFALL WILL LIKELY  
RESULT IN INCREASED HYDROLOGICAL CONCERNS...ESPECIALLY AS SNOW  
LEVELS RISE. HAVE THUS INTRODUCED A BROAD MARGINAL RISK ACROSS CA  
ON DAY 3...WITH ONE SLIGHT RISK ALONG THE COASTAL RANGES...AND  
ANOTHER ALONG THE WEST FACING SLOPES OF THE SIERRAS. WPC QPF WAS  
GENERALLY DERIVED FROM A BLEND OF THE GFS/NAM/ECMWF/UKMET FOR THIS  
SYSTEM. GOOD AGREEMENT FOR 1-3" ALONG THE COASTAL AREAS OF  
CENTRAL/NORTHERN CA...AND 3-5" (LOCALLY HIGHER) ACROSS THE SIERRAS  
THROUGH 12Z SUNDAY. AS MENTIONED ABOVE ADDITIONAL PRECIPITATION IS  
LIKELY AFTER 12Z.  
  
Link to comment
Share on other sites

15 hours ago, janetjanet998 said:

All systems still go

vanguard rain starting tonight..main wave saturday night into Sunday

then a couple of slightly weaker but decent systems next week

 

 

 

janetjanet998....  do you live in the west ? can't tell from your signature.  Thanks for posting this week.  Pretty amazing event for sure!

 I live in Central Oregon so colder here and most of the storms since early December have been frozen.  I have had 15 snows of 1/2" or more in the past 31 days and 51-1/2" of snow total .. snowing today and next Tuesday could be another decent snow??  Happy Winter and Cheers to a reduced west coast fire season this summer !! 

Link to comment
Share on other sites

57 minutes ago, snownut said:

janetjanet998....  do you live in the west ? can't tell from your signature.  Thanks for posting this week.  Pretty amazing event for sure!

 I live in Central Oregon so colder here and most of the storms since early December have been frozen.  I have had 15 snows of 1/2" or more in the past 31 days and 51-1/2" of snow total .. snowing today and next Tuesday could be another decent snow??  Happy Winter and Cheers to a reduced west coast fire season this summer !! 

No,  I'm in dry and cold IL 

12z NAM has 850MB winds of 80 kts at 18z sunday,   GFS 70 kts

Link to comment
Share on other sites

On January 5, 2017 at 1:05 PM, janetjanet998 said:

3 day totals ending for this event..it will likely be dry the next 36 hours

SAC  .26 + .87  + .25 =  1.38 

Redding  .16 + 1.89 +0 = 2.05

Blue Canyon 1.27 + 3.02 + 1.47 = 5.76

 

part 1 of round 2  as of noon saturday(last 24 hours of precip)...a brief break in the valley before the huge event tonight..still getting rates up to .25/in per hour in the hills even after this lull

SAC  .91

Redding  .79

Blue Canyon  .50

 

Link to comment
Share on other sites

Historic winter continues here in Central OR.. I have had 59" of snow at my house in the past 34 days.  Today was to be in the 30's with rain and freezing rain.  So far inversion is holding and mix of sleet and snow with temperature of 12 degrees at 12 noon.. after another night in the single digits last night.  

Potential for a big snowstorm again on Tuesday and Wednesday.  Doubt I will see the ground again for a long time and snow pile long into the spring months.  

 

Some photos.  Parking lot at my office this morning ... sea of snow piles ... picture of my back yard yesterday ... we had 6 more inches after I took that photo ! 

 

 

Back yard.jpg

Parking lot.jpg

Link to comment
Share on other sites

8 station index now at 41.9 inches over 200% of normal and a record for this time of year(average is 50 inches oct-oct and record is 88.5 in 1982-3)

in 1982-83 on Feb 1st the index was about 41

 

good news is that look like a 5-6 day break or so after this system

 

http://cdec.water.ca.gov/cgi-progs/products/PLOT_ESI.pdf

Link to comment
Share on other sites

Talk about ice :yikes:

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE PORTLAND OR
453 AM PST TUE JAN 17 2017

...MAJOR ICE STORM LIKELY TODAY THROUGH WEDNESDAY FOR THE HOOD
RIVER AND WIND RIVER VALLEYS...THE COLUMBIA RIVER GORGE...AS WELL
AS MANY VALLEYS WITHIN THE GIFFORD PINCHOT NATIONAL FOREST...

...FREEZING RAIN EXPECTED TUESDAY FOR THE GREATER PORTLAND AND
VANCOUVER METRO AREA...NEARBY VALLEYS IN THE COAST RANGE AND
CASCADES...AND THE CENTRAL AND SOUTH WILLAMETTE VALLEY...

.TEMPERATURES ARE EXPECTED TO REMAIN AT OR BELOW FREEZING UNDER
VALLEY INVERSIONS TONIGHT AND TUESDAY MORNING. MEANWHILE...A VERY
MOIST PACIFIC FRONTAL SYSTEM WILL SPREAD RAIN ACROSS THE REGION
THIS MORNING...INCREASING THIS AFTERNOON AND EVENING. THERE WILL
LIKELY BE SEVERAL HOURS OF RAIN BEFORE WARM AIR ALOFT CAN WORK ITS
WAY DOWN TO THE VALLEY FLOORS...LEADING TO THE POTENTIAL OF
SEVERAL HOURS OF FREEZING RAIN. AREAS IN AND NEAR THE COLUMBIA
GORGE WILL BE HARDEST HIT...AS THEY WILL BE THE LAST TO CLIMB
ABOVE FREEZING.

ORZ014>016-WAZ045-046-180100-
/O.CON.KPQR.IS.W.0002.170117T1400Z-170119T0200Z/
UPPER HOOD RIVER VALLEY-WESTERN COLUMBIA RIVER GORGE-
CENTRAL COLUMBIA RIVER GORGE-
INCLUDING THE CITIES OF...ODELL...CORBETT...HOOD RIVER...CARSON...
UNDERWOOD
453 AM PST TUE JAN 17 2017

...ICE STORM WARNING REMAINS IN EFFECT UNTIL 6 PM WEDNESDAY BELOW
2500 FEET FOR UPPER HOOD RIVER VALLEY AND THE COLUMBIA GORGE...

AN ICE STORM WARNING BELOW 2500 FEET FOR FREEZING RAIN AND SLEET REMAINS
IN EFFECT UNTIL 6 PM PST WEDNESDAY.

* TIMING...OCCASIONAL LIGHT PRECIPITATION TODAY. LATER TODAY AND
  TONIGHT...PRECIPITATION WILL INCREASE AND BECOME HEAVY AT TIMES.

* ICE ACCUMULATION...GENERALLY LESS THAN A TENTH OF AN INCH OF
  ACCUMULATION THROUGH EARLY THIS AFTERNOON. BUT AS PRECIPITATION
  INCREASES LATER TODAY AND TONIGHT...EXPECT MAJOR ICE
  ACCUMULATIONS. GENERALLY...ICE ACCUMULATIONS OF A HALF INCH TO
  ONE INCH WILL BE FAIRLY WIDESPREAD. SOME LOCATIONS MAY EXCEED
  ONE AND A HALF OF INCHES OF ICE FROM THIS STORM.

* IMPACTS...THIS IS EXPECTED TO BE YET ANOTHER MAJOR ICE STORM
  FOR THE WESTERN AND CENTRAL COLUMBIA GORGE AND SURROUNDING
  VALLEYS. HEAVY ICE ACCUMULATION WILL LIKELY BRING DOWN SOME
  LARGE BRANCHES AND POWER LINES. POWER OUTAGES MAY LAST
  MULTIPLE DAYS DEPENDING ON HOW WIDESPREAD THESE IMPACTS ARE.
  THIS EVENT WILL ONLY ADD TO THE EXISTING HEAVY SNOW AND ICE
  LOADING ON ROOFTOPS...WHICH MAY CAUSE SOME ROOFTOPS TO FAIL.
Link to comment
Share on other sites


URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE PORTLAND OR
453 AM PST TUE JAN 17 2017

...MAJOR ICE STORM LIKELY TODAY THROUGH WEDNESDAY FOR THE HOOD
RIVER AND WIND RIVER VALLEYS...THE COLUMBIA RIVER GORGE...AS WELL
AS MANY VALLEYS WITHIN THE GIFFORD PINCHOT NATIONAL FOREST...

...FREEZING RAIN EXPECTED TUESDAY FOR THE GREATER PORTLAND AND
VANCOUVER METRO AREA...NEARBY VALLEYS IN THE COAST RANGE AND
CASCADES...AND THE CENTRAL AND SOUTH WILLAMETTE VALLEY...

.TEMPERATURES ARE EXPECTED TO REMAIN AT OR BELOW FREEZING UNDER
VALLEY INVERSIONS TONIGHT AND TUESDAY MORNING. MEANWHILE...A VERY
MOIST PACIFIC FRONTAL SYSTEM WILL SPREAD RAIN ACROSS THE REGION
THIS MORNING...INCREASING THIS AFTERNOON AND EVENING. THERE WILL
LIKELY BE SEVERAL HOURS OF RAIN BEFORE WARM AIR ALOFT CAN WORK ITS
WAY DOWN TO THE VALLEY FLOORS...LEADING TO THE POTENTIAL OF
SEVERAL HOURS OF FREEZING RAIN. AREAS IN AND NEAR THE COLUMBIA
GORGE WILL BE HARDEST HIT...AS THEY WILL BE THE LAST TO CLIMB
ABOVE FREEZING.

WAZ019-180100-
/O.CON.KPQR.IS.W.0002.170117T1400Z-170119T0200Z/
SOUTH WASHINGTON CASCADES-
453 AM PST TUE JAN 17 2017

...ICE STORM WARNING REMAINS IN EFFECT UNTIL 6 PM WEDNESDAY BELOW
3000 FEET IN THE SOUTH WASHINGTON CASCADES...

AN ICE STORM WARNING BELOW 3000 FEET FOR FREEZING RAIN AND SLEET
REMAINS IN EFFECT UNTIL 6 PM PST WEDNESDAY.

* TIMING...OCCASIONAL LIGHT PRECIPITATION TODAY. BUT LATER TODAY
  AND TONIGHT...PRECIPITATION WILL INCREASE AND BECOME HEAVY AT
  TIMES.

* ICE ACCUMULATION...GENERALLY LESS THAN A TENTH OF AN INCH OF
  ACCUMULATION THROUGH EARLY THIS AFTERNOON. BUT AS PRECIPITATION
  INCREASES LATER TODAY AND TONIGHT...EXPECT MAJOR ICE
  ACCUMULATIONS. GENERALLY...ICE ACCUMULATIONS OF A HALF INCH TO
  ONE INCH WILL BE FAIRLY WIDESPREAD. SOME LOCATIONS COULD GET AS
  MUCH AS 2 INCHES OF ICE FROM THIS STORM.

* IMPACTS...HEAVY ICE ACCUMULATION WILL LIKELY BRING DOWN SOME
  LARGE BRANCHES AND POWER LINES. POWER OUTAGES MAY LAST
  MULTIPLE DAYS DEPENDING ON HOW WIDESPREAD THESE IMPACTS ARE.
  THIS EVENT WILL ONLY ADD TO THE EXISTING HEAVY SNOW AND ICE
  LOADING ON ROOFTOPS...WHICH MAY CAUSE SOME ROOFTOPS TO FAIL.
Link to comment
Share on other sites

  • 3 weeks later...

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...