One Of The Greatest Due West Coast Atmospheric Rivers On Record
The to a greater extent than I await at the rigid atmospheric river that volition strike California tomorrow, the to a greater extent than amazing it becomes. In some, only non all, respects it is 1 of the to a greater extent than extreme atmospheric rivers on record.
Today's H2O vapor satellite imagery shows a huge feather of wet stretching from the torrid zone towards California (see below)
And the values of vertically integrated H2O vapor (total H2O vapor inwards a vertical column of air) forecast for tomorrow (Friday) at two PM are immense, alongside the blueish colors indicating values of xl mm (1.6 inches) or more. That agency if 1 condensed out all the wet inwards a vertical column, 1.6 inches of pelting would result. That is a really large amount.
But for me, the most extraordinary purpose of this lawsuit is how odd it volition be, together with then allow me demonstrate that to you. Here is a plot of the forecast integrated H2O amount (also known every bit Total Precipitable Water) for San Francisco from the National Weather Service ensemble organisation (many forecasts using the GFS model). The amounts teach to 1.65 inches tomorrow together with Saturday--and this is a confident forecast (all the ensemble members are going for it). The dark work is the ensemble average...a really adept forecast to use.
So to repeat...this is belike the strongest atmospheric river, inwards damage of H2O vapor content, to receive got e'er hitting fundamental California when it actually counted (during the non-summer subdivision of the year). Just extraordinary.
But every bit rigid every bit this atmospheric river is inwards damage of wet content, it volition non move the wettest on tape (in damage of accumulated precipitation). Why? Because the incoming current has been much stronger inwards some past times events. And what actually counts inwards damage of producing atmospheric precipitation on the California mountains is both wet content AND the charge per unit of measurement at which air is forced to ascent on the terrain. Stronger incoming winds promote to a greater extent than rising, upward motion, together with hence precipitation.
What virtually the rigid oceanic cyclone approaching the Northwest on Saturday?
It is nevertheless coming.
Here is the latest sea degree pressure level forecast for two PM Saturday. Influenza A virus subtype H5N1 980 hPa depression off our coast alongside a really large pressure level slope due south of it. Very rigid winds offshore together with along the WA together with Oregon coastlines.
The depression volition tardily drift northwest of Seattle together with the latest UW air current gust forecasts over Seattle for v PM Sat shows 50-60 mph gusts over portions of Seattle, alongside xl mph+ gusts over much of the city. That volition make some ability outages, alongside some mitigation past times the fact that nosotros are at the halt of the winter, alongside a break of storms already clearing the weak stuff. And the trees are non leafed out yet.
Anyway, the entire West Coast volition move inwards for really active atmospheric condition the side past times side 72 hour.
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Announcement: The Northwest Weather Workshop is on Apr 27-28
The NW Weather Workshop is the large annual coming together for those interested inwards Northwest meteorology. This yr nosotros volition receive got a major session on the meteorology of NW wildfires together with others on other aspects of our regional weather. The gathering takes house at the NOAA facility inwards Seattle. To stance the agenda together with to register, move to the meeting website. The workshop is opened upwardly to everyone, only registration is required.
Today's H2O vapor satellite imagery shows a huge feather of wet stretching from the torrid zone towards California (see below)
This intense feather of H2O vapor volition tardily displace downward the California coast, reaching southern CA on Sat morn (below is the forecast map for 8 AM Saturday).
The latest forecasts hope major pelting (and considering the warmth of this atmospheric river, that is what it volition be, fifty-fifty over high terrain). For the 72-h ending v AM Sunday, the full amounts achieve 5-10 inches over the coastal mountains together with Sierra Nevada of fundamental together with northern CA--and nosotros likewise make "well" inwards the atmospheric precipitation arena.
But for me, the most extraordinary purpose of this lawsuit is how odd it volition be, together with then allow me demonstrate that to you. Here is a plot of the forecast integrated H2O amount (also known every bit Total Precipitable Water) for San Francisco from the National Weather Service ensemble organisation (many forecasts using the GFS model). The amounts teach to 1.65 inches tomorrow together with Saturday--and this is a confident forecast (all the ensemble members are going for it). The dark work is the ensemble average...a really adept forecast to use.
We tin teach a experience for how odd this is past times looking at the climatology of these precipitable H2O values using the nearby radiosonde (balloon-launched atmospheric condition observations) at Oakland, across the bay from San Francisco (see below). The averages for each twenty-four hours of the yr are shown inwards dark together with the daily records are indicated past times the upper carmine lines that gyrate upwardly together with down. The forecast value for tomorrow is shown past times the dark dashed line.
This is amazing: the forecast value tomorrow is higher than ANY DAY for the entire tape at Oakland (about seventy years) from the menses Oct 1 through July 1. So tomorrow volition non solely shell the daily record, only the tape for ANY twenty-four hours during the wet flavour of yr inwards California.
There receive got been some higher values during the summer, only that reflects to a greater extent than wet inwards the warmer summertime atmosphere...moisture that doesn't lawsuit inwards heavy precipitation, mainly because the incoming current is weak that fourth dimension of the year. To show this to you, hither are the extreme atmospheric precipitation events at Yosemite National Park for each twenty-four hours of the year. Extreme atmospheric precipitation is wimpy during the dry out summer.
So to repeat...this is belike the strongest atmospheric river, inwards damage of H2O vapor content, to receive got e'er hitting fundamental California when it actually counted (during the non-summer subdivision of the year). Just extraordinary.
But every bit rigid every bit this atmospheric river is inwards damage of wet content, it volition non move the wettest on tape (in damage of accumulated precipitation). Why? Because the incoming current has been much stronger inwards some past times events. And what actually counts inwards damage of producing atmospheric precipitation on the California mountains is both wet content AND the charge per unit of measurement at which air is forced to ascent on the terrain. Stronger incoming winds promote to a greater extent than rising, upward motion, together with hence precipitation.
What virtually the rigid oceanic cyclone approaching the Northwest on Saturday?
It is nevertheless coming.
Here is the latest sea degree pressure level forecast for two PM Saturday. Influenza A virus subtype H5N1 980 hPa depression off our coast alongside a really large pressure level slope due south of it. Very rigid winds offshore together with along the WA together with Oregon coastlines.
The depression volition tardily drift northwest of Seattle together with the latest UW air current gust forecasts over Seattle for v PM Sat shows 50-60 mph gusts over portions of Seattle, alongside xl mph+ gusts over much of the city. That volition make some ability outages, alongside some mitigation past times the fact that nosotros are at the halt of the winter, alongside a break of storms already clearing the weak stuff. And the trees are non leafed out yet.
________
Announcement: The Northwest Weather Workshop is on Apr 27-28
The NW Weather Workshop is the large annual coming together for those interested inwards Northwest meteorology. This yr nosotros volition receive got a major session on the meteorology of NW wildfires together with others on other aspects of our regional weather. The gathering takes house at the NOAA facility inwards Seattle. To stance the agenda together with to register, move to the meeting website. The workshop is opened upwardly to everyone, only registration is required.
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